What HDR Means in Camera Settings • BYRGPUB.COM

HDR mode in a smartphone: what is it?

01.12.2017 12:00:00

Smartphone camera, by default, and will not be able to match the quality of pictures with a professional DSLR. Of course, modern technologies make it possible to place advanced matrices, lenses in a mobile device, as well as the number of megapixels to the maximum. However, such means, as a rule, lead to the fact that the smartphone itself is more expensive than a regular “DSLR”.

In inexpensive phones, it is much more practical and convenient to use special frame processing technologies, which help to achieve a spectacular picture without numerous settings. In this article we will tell you about the most common snapshot algorithm. HDR technology.

HDR mode in a smartphone: what is it?

HDR stands for High Dynamic Range. high dynamic range). This mode allows you to programmatically select the ratio of brightness, color and contrast in the picture. The smartphone camera sequentially shoots three frames with different exposure, that is, the ratio of shutter speed and illumination. At the same time, automatic focus captures areas of the frame with different degrees of brightness and focal length.

After shooting, the system automatically analyzes the received frames and combines the final image, taking into account the clearest areas. The output is a photo with the perfect combination of dark, light, bright and contrasting details.

What is HDR mode for?

Thanks to the high dynamic range function, smartphone users can take better pictures than the standard mode. HDR helps to make the photo more detailed and rich. For example, when shooting landscapes or architectural objects in good lighting, only the details of the frame that have captured the focus of the camera will be perfectly worked out. In this case, the HDR mode will provide High definition objects that differ in color, brightness and distance from the photographer.

Here’s the simplest example. The top photo was taken with a Fly Cirrus 12 smartphone camera without HDR, the bottom one. with high dynamic range enabled.

A clever algorithm slightly darkened the wallpaper and made more contrasting areas where light tones combine with dark ones, in particular, the joints between the mosaic areas.

Disadvantages of HDR

Like most sophisticated technologies, the HDR shooting mode in a smartphone has a downside to its functionality:

This mode does not allow shooting subjects in motion. Since the camera takes at least three shots, in these fractions of a second, the object moves in the frame, so that the output is a blurry photo with knocked down layers;
HDR will NOT allow you to take a bright photo, since the built-in processor outputs the average brightness value over the frame;
With HDR, the camera shoots slightly slower than with standard settings. You will also have to wait while the camera software processes the image. So in some cases it is easier to shoot 10 frames in series than to wait until one is processed.

How to enable HDR in a smartphone camera

In order to take a picture using HDR, there is a need to get deep into the camera settings. It is enough to launch the system application, select the drop-down menu and click on the HDR icon.

There are several apps on Google Play that extend the functionality of the built-in HDR mode. The most popular and thoughtful are Pro HDR Camera and Ultimate HDR Camera.

Pro HDR Camera

This application costs 62 rubles, but the lack of a free version is fully justified by the fine settings of the HDR mode and the high quality of the finished images. The utility works in manual and automatic modes. In the first case, the user himself adjusts the areas that should be exposed, specifies the contrast, saturation, temperature and brightness.

Key features of the app:

Fast HDR Shooting
Built-in hints for the best shot
Three speeds of image capture
Sophisticated image alignment algorithm
Layered overlays of basic characteristics
Built-in HDR gallery
The ability to share the finished photo on social networks and blogs.

Ultimate HDR Camera

The Ultimate HDR Camera is free to download, so you’ll have to endure the built-in ads. over, the utility has a very sophisticated functionality. When you launch Ultimate HDR Camera, the application shell is embedded in the smartphone’s camera control. After taking a picture, the user can adjust the basic parameters of the image:

Shadow level
HDR level
Saturation
Brightness

The app also contains a built-in gallery, allows you to set a timer for shooting, turn on the flash and switch to the front camera.

Below are a couple of sample photos taken with the Ultimate HDR Camera:

What does HDR mean in camera settings. What is HDR and how HDR works in a smartphone camera?

High Dynamic Range (abbreviated. HDR) mode has recently appeared in smartphone cameras. However, the novelty of the technology did NOT prevent HDR from penetrating into both expensive flagships and mobile devices with more modest capabilities. But is this mode as good as smartphone marketers say it? Let’s try to deal with this issue and find out who and when will need High Dynamic Range.?

What is HDR

High Dynamic Range (high dynamic range). this is a special mode of operation that starts shooting a series of frames with subsequent processing of the results. The result of processing is one single snapshot, Assembled like a puzzle from the most successful pieces of the series.

The presence of the HDR mode in the phone allows you to take good shots Not only in ideal conditions. The fact is that each of the pictures in the series, taken apart into puzzles, is taken at different camera settings. In total, one part of the frame is better, and the other. worse.

Then a special algorithm collects from the Most Focused, Contrasting and Sharp Puzzles the Virtually Perfect Frame, suppressing all noise and increasing clarity and saturation. This is how the perfect shot is formed in non-ideal conditions.

How HDR works

The HDR mode in the smartphone camera is realized through the use of software and hardware. The former are responsible for post-processing, and the latter. information accumulation.

Of the smartphone camera hardware, the autofocus module is most involved in HDR. It is he who directs the lens alternately at the objects of the foreground, then at the elements of the background. In addition, the brightest / darkest objects, as well as elements of the frame with different contrast ratios, attract the attention of the automatic focus. All of them are filmed both “in focus” and in defocus mode.

In addition, HDR also puts a load on the mechanisms responsible for the shutter speed and exposure of the smartphone camera. All frames in the series are shot with a different exposure period, so along with autofocus, the electronic shutter also works to create the perfect picture. Variable intervals during which the shutter transmits light to the sensor can enhance both the light and dark areas of the image. The former are shot with a short shutter speed, and the latter with a long exposure.

Example. When shooting a cityscape or landscape on a sunny day, as well as when shooting in the evening, there is one difficulty. Well-lit areas will get overexposed if you set the exposure for shady areas, and vice versa, the “shadow” will be too dark if you optimize shutter speed and exposures for bright areas. HDR allows you to take multiple pictures. some with ideal shadow settings, others. with tinctures for the bright area, and then collect the Flawless (as far as possible) frame. As a result of all THESE dances with a tambourine, the light areas will turn out to be slightly darker, and the dark ones. slightly lighter, which can be clearly seen in the example of the image from the Google Pixel camera. (In-camera HDR is enabled in second shot).

After the accumulation of information, the second stage of HDR work on the phone is turned on. processing of the obtained puzzle frames and forming a picture from them with perfect detail and picture clarity. For this, special algorithms and programs are written that are optimized for the capabilities of the processor chipsets and camera characteristics (shutter speed and autofocus aiming speed, sensor light sensitivity, camera lens aperture, and so on).

After reworking the puzzles, the user gets a finished picture with improved characteristics. In this case, there is no way to delve into intermediate frames; for a smartphone owner, this whole procedure looks like displaying a snapshot on the screen with a slight delay.

Cons of HDR mode

Optimization delays framing and overloads the smartphone chipset, consuming computing resources. But you can put up with these shortcomings. After all, almost all applications freeze and suspend the chip. However, the HDR mode, activated in the smartphone camera, has more serious drawbacks that limit its scope.

First, we are talking about the impossibility of fixing Dynamic objects. Simply put, humans, animals, vehicles and other moving animate and inanimate objects cannot be filmed using HDR on a phone. This will give you blurry spots instead of a clear shot, because the subject moves towards the photographer.

Secondly, active HDR in a smartphone camera suppresses, or rather, averages the brightness of the frame. The simplest processing algorithm involves the trivial overlaying of puzzle pictures in layers, so a picture without active dynamic mode will have a brighter foreground or background than in an HDR frame.

And the speed of the smartphone camera with active HDR suffers greatly. This is especially noticeable on gadgets with weak processors, which cannot boast of computing speed. Some owners of such phones even claim that it is easier for them to take 5-10 simple frames and choose the most successful one than to wait for the HDR image to be processed.

All this, of course, imposes its own limitations on the practice of using HDR mode in the phone.

Who needs HDR and when

You should enable HDR on your smartphone camera in the following cases:

We are drawn to such conclusions by analyzing the advantages and disadvantages of the High Dynamic Range mode. Well, if our readers have their own opinion, supported by practical experience, then they can Supplement our conclusions in the comments to this article.

In-camera HDR shooting mode. what it is?

The contemporary art of photography is not only about capturing the beauty of the moment or capturing the subject in the best possible angle. Many photographers today strive to enhance their photos by passing them through various filters and adding Special Effects. One of these effects will be discussed today. It is called High Dynamic Range (abbreviated as HDR) or high dynamic range.

A little about technology

Many digital camera owners have heard of HDR technology, but not all of them understand how it works. So what exactly is HDR? The human eye is truly a miracle of technology. Unlike cameras, it easily adapts to changes in lighting up to 24 stops of exposure, thanks to which we can distinguish fine details equally well against dark and light backgrounds. The dynamic range of most digital cameras is much lower, it is difficult for them to adapt to the light, so they only capture well areas with a certain level of illumination.

So, if we succeed in capturing a dark building against the background of a light sky, the latter often turns into a blurry whitish spot and vice versa, if the light sky comes out well, the detail of the dark building is lost, and the area of the photo where it is located turns out to be noisy. These flaws are especially evident in photographs taken with imperfect mobile phone cameras. HDR technology is aimed at eliminating this shortcoming. When using the HDR mode, the camera takes a series of shots with different shutter speeds and exposures, while autofocus during the shooting is alternately concentrated on areas with different illumination levels and distance from the lens.

Having created several frames, the camera then combines them with the software method into one saturated and detailed image in dark and light areas. This is the key difference between HDR shots and regular photos. The quality of the resulting image depends on the algorithm used. The photos are of lower quality, in which the pictures are simply superimposed on each other and slightly shaded. To obtain HDR photos of a higher quality, various sections of the frames are additionally analyzed in order to identify the most successful.

HDR mode in camera phone and camera

When working with a camera, there are two ways to create a high dynamic range photo. The first is more complex, longer and is used mainly when shooting with professional digital cameras. Its essence is as follows. The photographer takes three to five shots in Bracketing mode, and then stitches the resulting frames on a computer using Photomatix or another similar program. Then the resulting image is optimized for correct display on displays.

But there is also an easier way to get HDR photos. Many modern cameras, including those built into phones, allow you to shoot HDR in automatic mode. The camera does everything for you. She herself sets the required exposure, takes continuous shots herself, glues and processes the resulting frames herself. In Nikon cameras, for example, you can enable the HDR option in the Photo Shooting Menu settings. HDR. HDR mode. On.

The automatic HDR mode in a smartphone works on the same principle. The phone’s built-in camera takes two or three frames and immediately saves them into a single JPEG image. As a rule, HDR in the phone camera is enabled in its settings. In some models of accessories, the option is located in the subsection of effects, in others, a separate icon next to the flash is provided to activate it. Often, the options provide the ability to manually adjust the exposure.

HDR TVs

HDR technology today is supported not only by cameras, but also by some TVs with 4K resolution, for example, Vizio P50-C1, Sony XD8005 or Samsung KU7000. The picture in such TVs has more saturated colors, dark areas look even darker, and light ones. even lighter, due to which greater detail is achieved.

However, HDR support in a TV is not at all possible that HDR support in cameras. If in cameras the effect is applied at the time of creating a photo, then in TV. at the moment of showing the picture. In fact, this means that in order to obtain the HDR effect, the content itself must initially support, which is currently very small.

What you need to know when shooting HDR

Use HDR mode when shooting landscapes, single subjects, and for detailing in low light conditions. It is strongly recommended to use a tripod in order to avoid shifting and, as a consequence, misalignment of frames when shooting. But for photographing moving objects, HDR shooting is not suitable, since the photos will turn out to be blurry.

It is preferable to create HDR photos in the classical way with the introduction of manual settings and third-party desktop programs, in this case the photo is of higher quality. At the same time, if the original images were created in RAW format, tone compression will be required, otherwise the HDR photo will look somewhat unnatural on computer monitors.

HDR imaging software

It is important to understand that you can get real HDR photos only by merging and processing several frames taken with different exposures, and it does not matter whether the photos are created manually or automatically by the device camera. As for creating HDR images from regular JPEG or even RAW files using programs like Dynamic photo HDR or Photomatix Pro, then in this case we can only talk about giving a high dynamic range effect, but perhaps not creating a full HDR.

It is impossible to create an HDR photo from 8-bit images, which you usually have to deal with on the Internet, nor can you create it by lightening shadows and darkening highlights from one RAW file. In either case, the resulting file will be a pseudo HDR image. Nevertheless, using applications such as EasyHDR, Photomatix Pro, HDR Efex Pro, Adobe Photoshop, Dynamic photo HDR, Corel PaintShop Pro and the like, you can give ordinary images like HDR, improve color, add a surreal effect to them.

Perfect photo. What is HDR and how to activate it on your smartphone

What is HDR

To fully understand how HDR works, you’ll first have to deal with regular HDR.

The main problem with all smartphone cameras. small size of the matrix (or rather, photo cells) and, as a consequence, insufficient coverage of the dynamic range. To correct this drawback, an HDR (High-Dynamic Range) algorithm was developed, the principle of which is as follows: the camera takes a frame with a standard exposure level for a given scene, then takes an underexposed frame, in which only overexposed areas of the original image will be clearly visible, then it is performed an overexposed photo, in which only the darkened details of the original image are visible, and everything else is overexposed. Then the images are superimposed on each other and combined using Special algorithms, the quality of which depends on the manufacturer of the camera software. The result is a shot with good detailing both in the shadows and in lighter areas.

The disadvantages of HDR are obvious: a long shooting time leads to the fact that moving objects caught in the frame will double, and even a slight shaking will blur the picture.

What is HDR

Smart heads have come up with an algorithm devoid of HDR flaws. However, it has only a name in common with HDR.

HDR stands for High-Dynamic Range Low Noise. He gained his fame for a number of outstanding features: the algorithm is able to eliminate noise with virtually no loss of detail, higher color reproduction quality, which is extremely important in low light and at the edges of the frame, at the same time it greatly expands the dynamic range of photography. HDR, unlike standard HDR, Almost not afraid of smartphone shaking and movement in the frame.

The first smartphone with HDR support was the Nexus 5. Due to more than one better white balance and a small aperture (f2.4), the camera of this smartphone was considered no more than a strong middling. That all changed with the release of the Android 4.4.2 update. It was this that brought with it support for HDR mode and Amazing quality of night shots. Although they did NOT differ in high brightness across the entire field of the frame, thanks to HDR, they practically did NOT contain noise while preserving fine details and had excellent (for smartphones in 2013) color reproduction.

Nexus 5 HDR

The history of HDR creation

How did a company that has NEVER dealt with cameras create an algorithm that works wonders using conventional Nexus and Pixel cameras by flagship standards??

It all started in 2011, when Sebastian Thrun, CEO of Google X (now just X), was looking for a camera for Google Glass augmented reality glasses. The weight and size requirements were very strict. The size of the camera matrix had to be even smaller than in smartphones, which would have an extremely bad effect on the dynamic range and would lead to a lot of noise in the photo.

There was only one way out. try to improve the photo programmatically, using algorithms. This task was to be solved by Marc Levoy, a professor of computer science at Stanford University, an expert in the field of computational photography. He worked in software-based image capture and processing technology.

Mark formed a team known as Gcam to explore the Image Fusion method, which combines a series of images into a single frame. Photos processed using this method turned out to be brighter and sharper, had a small amount of noise. In 2013, the technology debuted in Google Glass, and then, in the same year, renamed HDR, appeared in the Nexus 5.

Another night shot from the Nexus 5

How HDR works

HDR. An extremely complex technology, which cannot be analyzed in detail within the framework of this article. Therefore, we will consider the general principle of operation, and not dwelling on the details.

Fundamental principle

After pressing the shutter button, the camera captures a series of underexposed (fast shutter speeds) frames (this is necessary to preserve the maximum amount of detail in the image). The number of frames depends on the complexity of the lighting conditions. The darker the scene or the more details in the shadow need to be illuminated, the more frames the smartphone takes.

When a series of shots has been taken, it is combined into one shot. A slow shutter speed comes in handy here, thanks to which every photo in the series looks very clear. Of the first three frames, the most acceptable in terms of both sharpness and detail is selected to use as a basis. Then the obtained images are divided into fragments and the system checks whether it is possible to combine adjacent fragments and how to do it. Having found unnecessary objects in one of the fragments, the algorithm removes this fragment and selects a similar one from another frame. The resulting images are processed using a special algorithm based on the method of successful exposures (it is mainly used in astrophotography to reduce image blur caused by the twinkling atmosphere of the Earth).

Next, a sophisticated noise reduction system comes into play, which includes both a simple method of averaging the color of pixels based on several images, and a system for predicting the appearance of noise. The algorithm works very gently at the edges of key transitions to minimize loss of detail, even at the cost of a small amount of noise in such places. But in areas with a uniform texture, “noise reduction” evens out the picture up to an almost perfectly uniform tone while maintaining the transition of shades.

Shumodav work in difficult conditions. On the left for processing, and on the right. after

But what about the expansion of the dynamic range? As we already know, using a fast shutter speed saves us from overexposed areas. It remains only to remove noise in the dark area using the previously described method.

At the final stage, post-processing of the resulting image is performed: the algorithm minimizes vignetting caused by light hitting the matrix at an oblique angle, corrects chromatic aberration by replacing pixels in high-contrast edges with neighboring ones, increases the saturation of greens, blues and magenta shades are shifted towards cyan, sharpens ) and performs a number of other steps to improve the quality of the photo.

An illustration of the HDR pipeline algorithm from the developer’s talk

On the left is a photo from a stock Samsung camera in HDR, and the case is a photo taken in Gcam in HDR. It can be seen that the algorithm sacrificed sky detail to draw objects on the ground.

HDR update on Google Pixel

In Google Pixel, the algorithm has undergone significant changes. Now the smartphone starts shooting immediately after starting the camera and, depending on the degree of illumination, takes from 15 to 30 frames per second. This technology is called ZSL (Zero Shutting Lag) and was invented to take snapshots. But Pixel uses it to work HDR: when you press the shutter button, the smartphone selects from 2 to 10 frames from the ZSL buffer (depending on lighting conditions and the presence of moving objects). Then the best one is selected from the first two or three frames, and the rest, as in the previous version of the algorithm, are layered on the main one.

Along with this, a division into two modes appeared: HDR Auto and HDR. The latter takes as many shots as possible to create the final photo. It turns out to be more juicy and bright.

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HDR mode in a smartphone: what is it?

01.12.2017 12:00:00

HDR mode in a smartphone: what is it?

What is HDR mode for?

Here’s the simplest example. The top photo was taken with a Fly Cirrus 12 smartphone camera without HDR, the bottom one. with high dynamic range enabled.

A clever algorithm slightly darkened the wallpaper and made more contrasting areas where light tones combine with dark ones, in particular, the joints between the mosaic areas.

Disadvantages of HDR

Like most sophisticated technologies, the HDR shooting mode in a smartphone has a downside to its functionality:

This mode does not allow shooting subjects in motion. Since the camera takes at least three shots, in these fractions of a second, the object moves in the frame, so that the output is a blurry photo with knocked down layers;
HDR will NOT allow you to take a bright photo, since the built-in processor outputs the average brightness value over the frame;
With HDR, the camera shoots slightly slower than with standard settings. You will also have to wait while the camera software processes the image. So in some cases it is easier to shoot 10 frames in series than to wait until one is processed.

How to enable HDR in a smartphone camera

In order to take a picture using HDR, there is a need to get deep into the camera settings. It is enough to launch the system application, select the drop-down menu and click on the HDR icon.

There are several apps on Google Play that extend the functionality of the built-in HDR mode. The most popular and thoughtful are Pro HDR Camera and Ultimate HDR Camera.

Pro HDR Camera

This application costs 62 rubles, but the lack of a free version is fully justified by the fine settings of the HDR mode and the high quality of the finished images. The utility works in manual and automatic modes. In the first case, the user himself adjusts the areas that should be exposed, specifies the contrast, saturation, temperature and brightness.

Key features of the app:

Fast HDR Shooting
Built-in hints for the best shot
Three speeds of image capture
Sophisticated image alignment algorithm
Layered overlays of basic characteristics
Built-in HDR gallery
The ability to share the finished photo on social networks and blogs.

Ultimate HDR Camera

Shadow level
HDR level
Saturation
Brightness

The app also contains a built-in gallery, allows you to set a timer for shooting, turn on the flash and switch to the front camera.

Below are a couple of sample photos taken with the Ultimate HDR Camera:

The shooting process in the application can be viewed here:

Now you know what HDR is in a smartphone camera and what factors to consider when taking HDR shots. Do you have spectacular footage captured in this mode? Share your best work in the comments to this article!

HDR in a phone camera: what is it?

You’ve probably heard that modern smartphones support HDR shooting mode. This article will give you an idea of what its essence is.

HDR technology was NOT inventions yesterday. However, its appearance could not have happened in the era of film cameras. Also, the HDR mode could not be present in the first digital cameras and smartphones. they simply wouldn’t have the power to process the images at the speed they needed. It is now such devices that allow you to make a couple of frames in a matter of seconds. So, let’s already understand what HDR is in a smartphone camera.

When to turn on HDR mode?

Any digital camera, including the one built into a phone, has a limited dynamic range. This means that if there are very bright areas in the frame, problems with dark objects begin. For example, you are photographing a building in its shadow. Most likely, this will lead to one of two versions of the resulting image:

The clouds in the sky will be clearly visible, but the details of the building itself will be almost indistinguishable;
The house will turn out to be detailed, but the sky will turn into white Gruel. in some cases, it hides the roof of the building in its colors.

This is where HDR comes in handy. This mode allows, roughly speaking, to make two shots with different exposures, then combining them into one. As a result, there will be no very dark areas in the picture, nor will there be too bright areas. The detail will increase significantly. absolutely all objects will be distinguishable. But do not use this mode on an ongoing basis. The fact is that HDR photos often look a little fake. It is worth activating the mode if the device camera does not cope with its task. For example, you are shooting against the light of the sun or in the shadow of a building. then you can use HDR.

Pay attention to the area in the shadow: it turned out to be light, and the details are clearly visible

It is noted that owners of budget smartphones use HDR mode much more often than owners of top-end devices. The fact is that expensive devices are equipped with a better camera with a wide dynamic range.

How it works?

When HDR is activated, be prepared for the camera to take multiple shots at once. two or even three. Therefore, it is not worth photographing moving objects in this mode, they can split in two, turning into a kind of ghosts, or blurred. Pictures will be taken with different shutter speeds and exposures. Specific shutter speed values depend on the optical aperture ratio, matrix size and many other parameters. That is why full-fledged cameras cope with this task much faster.

Then the received frames are merged into one. The more powerful the processor is installed in the camera or smartphone, the less time this process will take. Although you should NOT forget about the resolution of the matrix. Of course, 24-megapixel images are more difficult to process than 8-megapixel frames. In any case, even on budget devices, you will see the result in a couple of seconds.

Another example of an HDR shot

When taking photographs, autofocus focuses on areas with different indicators of brightness, contrast and distance from the camera. When frames are superimposed on each other, the system analyzes their quality, selecting areas with the highest clarity. Also, the final image will consist of areas with better saturation and less noise.

High Dynamic Range technology in different smartphones can be implemented in completely different ways. Somewhere the pictures are simply superimposed on each other, and then slightly blurred. And on more powerful and new devices, the above process takes place.

How to shoot in HDR mode?

Now almost all Camera applications, which are equipped with modern smartphones, are endowed with the corresponding function. This means that you do not need to install any additional photography applications. The HDR icon can be found in the mode selection menu. And in many cases it can be found right on the main Camera screen, next to the flash activation. Be that as it may, but you need to touch this icon.

Then you take a picture with the usual touch of the shutter button. But if a regular photo is created in a split second, then in the case of HDR mode, you will have to wait a while. Try to hold your smartphone still for one or two seconds. It is important! Otherwise, you will succeed.

Some third party applications Provide HDR mode settings. That is, you can choose how much the exposure will change when creating multiple frames. In the preinstalled programs “Camera” this setting is usually available.

The difference between regular photo and HDR is obvious.

That’s it, HDR photography is ready! Nothing complicated!

Disadvantages of HDR

Let’s summarize briefly. The main advantage of the HDR mode should be clear to you: all areas of the frame made in it will be equally detailed and bright. And what are the disadvantages of such a regime?

Shooting multiple shots takes time. and the worse the camera built into the smartphone, the more chances you have to get an image with blurred objects at the output. Unnatural lighting. the reality in the final photo will be far from what you saw with your own eyes. You can miss the moment. processing images in HDR-mode Takes at least a couple of seconds. Burst shooting is thus excluded.

Now you understand the beauty of HDR shooting, as well as its main disadvantages. We hope you have learned something new for yourself. Be sure to share your opinion in the comments if you use the HDR function and if it is well implemented in your smartphone.

What does HDR mean in camera settings

Want to photograph a shaded object against the sun? With conventional cameras, either the sky is too bright or the subject is too dark. HDR lets you take the best of both.

What is HDR?

The abbreviation HDR stands for High Dynamic Range. In HDR mode, the Camera app on iPhone, iPad, and iPod touch automatically combines the best portions of three quick shots at different exposures: normal, dark, and high. A total of one shot with excellent detail and color rendition.

Underexposure

Sky exposure makes the subject too dark.

Overexposure

Exposure to subject makes the sky too bright.

HDR mode

With HDR, you get an image with optimal light and detail.

Taking photos in HDR mode

Open the Camera app on your iPhone, iPad, or iPod touch.
Press HDR and set it to HDR On or “HDR auto”.
Point the camera at the subject.
Click the icon.

When you take a photo in HDR mode, your device saves two versions of the image in Photos, with and without HDR. This allows you to compare the results and choose your Most liked. To save space, you can turn this feature off and save only the HDR version to your library. Select “Settings” Camera “Leave original” and Turn off this mode.

In HDR on mode the device creates an HDR version of each shot. In HDR auto mode, the device determines for each shot which version looks better: with or without HDR.

Until recently, the cameras of cell phones from the Pixel and Nexus line were nothing special, but Google developers implemented a new HDR photo post-processing engine, thanks to which they climbed to the first positions of various ratings. And if you’re curious about how HDR works and how to activate it on your smartphone.

What is normal HDR

To understand how HDR works, let’s start with regular HDR.

The coverage of the dynamic range is insufficient due to the small size of the matrix. the main disadvantage of all smartphone cameras. To solve this problem, an HDR (High-Dynamic Range) algorithm was developed, the principle of which is to superimpose and combine three images: a frame with a standard exposure level for a given scene, an underexposed frame, where only overexposed areas of the original image and the overexposed one are clearly visible. a frame in which only the dark areas of the original image are visible. The result is a snapshot with a good study of all the details. This method can be called a small revolution in smartphone photography.

The disadvantages of the HDR algorithm include: long shooting time, bifurcation of objects moving in the frame, as well as blurring the entire picture even with minimal movement or camera shake.

What is HDR

HDR (High-Dynamic Range Low Noise). it is an algorithm that has a number of outstanding features while free from the disadvantages of HDR. Unlike HDR, the new HDR algorithm is almost not afraid of smartphone shaking and movements in the frame. In addition, this algorithm is capable of improving the quality of color reproduction, which is extremely important in low light and at the edges of the frame, at the same time it greatly expands the dynamic range of the photo. Finally, the HDR algorithm is able to remove noise with virtually no loss of detail.

The first smartphone to have HDR support in 2013 was the Nexus 5. Android 4.4.2 update, which brought with it HDR support, which radically changed the quality of night shots. The brightness across the entire field of the frame has not changed very much, of course, but while maintaining small details, the noise practically disappeared. And of course, I could not fail to please the excellent color reproduction, which sharply distinguished the pictures of the Nexus 5 from the pictures of the second smartphones of that time.

The history of HDR creation

The story of creating an algorithm that works wonders using conventional Nexus and Pixel cameras began in 2011, when the head of Google X Sebastian Thrun decided to find a camera for Google Glass augmented reality glasses. He had very strict requirements for weight and dimensions. The size of the camera matrix had to be made even smaller than in a smartphone, which would have led to the appearance of a large amount of noise in the picture. Therefore, it was decided to try to improve the quality of the photo using algorithms. This is what Marc Levoy, a professor of computer science at Stanford University, an expert in computational photography, took up. Yakiy was engaged in software-based image capture and processing technology.

The Gcam team, led by M. Leva, began to study the method of combining several images into one frame (Image Fusion). The quality of photos processed with this method has improved markedly. They became brighter and clearer, and the amount of noise significantly decreased.

This technology debuted in 2013 on Google Glass. Then, renamed to HDR, appeared in the Nexus 5 the same year.

Another night shot from the Nexus 5

How HDR works

HDR technology. Extremely challenging. Therefore, we will NOT disassemble it in detail within the framework of this article, but we will consider the main principle of operation.

The basic principle of HDR

To preserve as much detail as possible in the final photo, after pressing the shutter button, the camera captures a whole series of frames at fast shutter speeds, i.e. Underexposed shots. The number of frames depends on the light level and the amount of shadow detail. Then the entire series of images is combined into one.

Thanks to the slower shutter speed, every photo in the series is sharp. For the base, the best of the first three frames is used in both sharpness and detail. After that, the system divides all received frames from this series into fragments and checks the neighboring fragments for compatibility. In case of detecting unnecessary objects in one of the fragments, the algorithm removes this fragment and selects a similar one from the other frame. Then the images are processed using a special algorithm to reduce image blur, which is mainly used in astrophotography.

So, the use of a fast shutter speed relieves our photos of overexposed places, Expand the dynamic range of the image. It remains only to remove noise in dark areas with a special algorithm.

After that, the photo is processed by a noise reduction system. The system includes a method for averaging pixel color based on multiple images and a noise prediction system. At the boundaries of tone transitions and texture changes, the purpose of the “noise reduction” is to minimize the loss of detail even at the cost of a little noise, but in areas with a uniform texture, the algorithm aligns the picture in an almost perfectly uniform tone and with excellent preservation of transitions of all shades.

Shumodav work in difficult conditions. On the left for processing, and on the right. after

Finally, post-processing of the resulting image is performed. The algorithm minimizes the partial darkening resulting from light falling at an oblique angle (vignetting). Replaces pixels of high-contrast edges with adjacent ones (chromatic aberration). The shades of green are richer, blues and magentas are shifted towards cyan. It also enhances sharpness (sharpening) and makes other operations that significantly improve the quality of the final photo.

HDR pipelined algorithm at work.

A photo taken with Samsung’s stock HDR camera, on the left, and a photo taken with Gcam in HDR on the right. When comparing THESE two photos, it is striking that due to the loss of sky detail, objects on the ground are better drawn.

Google Pixel HDR update difference

ZSL (Zero Shutting Lag) technology was invented to take snapshots. The smartphone immediately after starting the camera shoots from 15 to 30 frames per second, depending on the degree of illumination. Pixel decided to use this technology to work HDR in its own way. When you press the shutter button, the smartphone selects from 2 to 10 frames from the ZSL buffer. Then the best one is selected from the first two or three frames, and the rest, as in the previous version of the algorithm, are layered on the main one.

Along with this, a division into two modes appeared: HDR Auto and HDR. The latter takes as many shots as possible to create the final photo. It turns out to be more juicy and bright.

HDR Auto takes fewer photos, making moving subjects less blurry, less hand shake, and a photo ready almost instantly after pressing the capture button.

In the Pixel 2 / 2XL version of Google Camera, HDR Auto has been renamed to HDR On and HDR has been renamed HDR Enhanced.

The second generation Google Pixel has a special coprocessor called the Pixel Visual Core. Currently, the chip is only used for accelerated processing of photos in HDR mode, and also provides third-party applications with the ability to take pictures in HDR. The quality of photos taken by Google camera, its presence or absence does NOT affect in any way.

Google even uses HDR to fix hardware issues. Due to a constructive error on the Google Pixel / Pixel XL, it could take a photo with a lot of light. Google has released an update that uses HDR to remove this light by combining shots.

HDR advantages and disadvantages

Let’s highlight the main advantages of HDR:

The algorithm remarkably removes noise from photos, practically without distorting details.
Colors in dark scenes are much richer than in single-frame shooting.
Moving subjects are less likely to double in images than when shooting in HDR mode.
Even when framing in low light conditions, camera shake is minimized for blurring.
Wider dynamic range than without HDR.
Color reproduction is mostly more natural than with single-frame shooting (not for all smartphones), especially in the corners of the picture.

In the illustrations below, on the left is a photograph from the stock camera of the Galaxy S7, and on the right. photo in HDR via Google Camera on the same device.

Night photos of the city. Here you can clearly see that HDR gives us the opportunity to get a clear image of a group of people located under the Beeline sign. The sky looks clear, the road sign is clear. The grass is green, as it should be. Beeline sign with correct color rendering. Distinct drawing of balconies, wires and tree crowns. Important. the elaboration of details on the trees, the case (in the shadow) in HDR is slightly worse than in the stock camera.

There are few shortcomings in HDR, and they are insignificant for most scenes. First, it takes a lot of CPU and RAM to create HDR photos, which leads to a number of negative consequences:

Battery drain increases and device gets warm when Combining a series of pictures;
Multiple shots cannot be taken quickly;
Instant preview is not available; the photo will appear in the gallery after the end of processing, which on Snapdragon 810 lasts from up to four seconds.

Some of these problems have already been resolved using Pixel Visual Core. But this coprocessor will most likely remain the Google Pixel’s trump card.

Secondly, for the algorithm to work, at least two photos are required, and on average four to five frames are captured. Therefore:

Situations will surely arise in which the algorithms will fail;
HDR loses slightly to classic HDR in terms of dynamic range coverage;
The creation of one photo and its processing with the introduction of a fast ISP coprocessor will be preferable in action scenes, because it allows you to avoid ghosting and blurring of objects at low exposure.

Disadvantages of HDR from its developers’ report

Night photography with many moving objects

What devices does HDR work on

Theoretically, HDR can work on any smartphone with Android version 5.0 or higher (Camera2 API is required). But for marketing reasons, and also due to the presence of Some optimizations requiring Special hardware components (Hexagon coprocessor in Snapdragon), Google deliberately blocked the inclusion of HDR on any device other than the Pixel. However, Android would not be Android if enthusiasts did NOT find a way to get around this limitation.

In August 2017, one of the w3bsit3-dns.com users managed to modify the Google Camera application so that HDR mode can be used on any smartphone with a Hexagon 680 signal processor (Snapdragon 820) and Camera2 API enabled. At first, the mod did NOT support ZSL, and in general it looked damp. But even this was enough to improve the quality of photography of smartphones Xiaomi Mi5S, OnePlus 3 and others to a previously unattainable level for them, and HTC U11 got the opportunity to compete on equal terms with Google Pixel.

Later, other developers joined in adapting Google Camera to third-party phones. After a while, HDR even worked on devices with Snapdragon 808 and 810. Today, for almost every smartphone based on Snapdragon ARMv8 running Android 7 (in some cases Android 6) and having the ability to use the Camera2 API, there is a ported version of Google Camera. It is often maintained by an individual enthusiast, but usually there are several such developers at once.

In early January 2018, XDA users miniuser123 managed to run Google Camera with HDR on their Galaxy S7 with Exynos processor. A little later it turned out that Google Camera also worked on Galaxy S8 and Note 8. The first versions for Exynos were unstable, often crashed and freezed, they did not work with optical image stabilization and ZSL. Version 3.3 is already quite stable, it supports optical image stabilization and ZSL and all Google Camera features except for portrait mode. Supported devices now include multiple Samsung A series smartphones.

How to enable HDR on your phone

If you have an Exynos smartphone, then the choice is limited. Transitions to the topic of discussion on XDA. Open the spoiler V8.3b Base (if you have Android or Pixe2Mod Base (for Android 7) and download the latest version. You can also visit the group on Telegram. Where all Google Camera updates are quickly posted.

Smartphone owners with the Qualcomm process will have to look around. Enthusiasts actively support HDR versions of Google Camera for a variety of smartphones. I recommend to google and walk around the topics of discussion of the camera and the device itself in forums such as XDA. At least there will be users trying to trigger HDR.

In addition to all of the above, I will mention that there is a page on the Internet that contains almost all versions of Google Camera. On which it is convenient to test various Gcam on little-known devices.

HDR is a powerful demonstration of the power of mobile digital photography. This is perhaps the most efficient image processing algorithm available today. HDR, one photomodule is enough to create a picture that bypasses the double photomodule of some gadgets in quality.

A little about technology

So, if we succeed in capturing a dark building against the background of a light sky, the latter often turns into a blurry whitish spot and vice versa, if the light sky comes out well, the detail of the dark building is lost, and the area of the photo where it is located turns out to be noisy. These flaws are especially evident in photographs taken with imperfect mobile phone cameras. HDR technology is aimed at eliminating this shortcoming. When using the HDR mode, the camera takes a series of shots with different shutter speeds and exposures, while autofocus during the shooting is alternately concentrated on areas with different illumination levels and distance from the lens.

HDR mode in camera phone and camera

HDR TVs

What you need to know when shooting HDR

HDR imaging software

What is HDR Auto HDR and Smart HDR in iPhone camera, should it be turned on, and how does it affect photo quality

Smart HDR is, as the name suggests, similar to normal HDR, but smarter. This feature first appeared on the iPhone XS, iPhone XS Max, and iPhone XR in 2018. It takes full advantage of all camera sensors, the power of the A12 Bionic neural chip, machine learning, artificial intelligence, computer vision and the latest advances in mobile photography. Smart HDR makes it easy for all iPhone users to take photos with sufficient light and high dynamic range.

The user is NOT required to delve into fine-tuning. you just press the shutter button and the iPhone does the rest. But behind such a simple feature lies sophisticated technology that takes full advantage of Apple-designed processors and graphics chips. This hardware is optimized to interact with the camera software to take beautiful pictures effortlessly.

Previous iPhones already had regular HDR and Auto HDR, but Smart HDR debuted on the iPhone XS / XR series.

Smart HDR delivers better color quality and allows you to capture more light and dark details in your photos

On older models, it will NOT be possible to implement the function due to the lack of the required fast sensors, shutter lag and other new improvements. Auto HDR users are mainly used to capture a moment in time with more detail and take clearer realistic shots.

What is HDR

This abbreviation itself literally stands for High Dynamic Range. This is the name given to a digital photography technique that allows you to take great pictures in scenes with high contrast levels. HDR allows you to compose something into several similar images to expand the dynamic range beyond the built-in capabilities of the capture device. This feature works best when photographing a shaded subject against a bright background.

Only HDR makes such shots possible: excellent detail in low light, no sky too bright on the right side of the shot

On traditional DSLR cameras, you have to choose between too bright a background or a shaded subject. HDR, on the other hand, allows you to display high-quality both. With this feature enabled, iOS quickly takes three consecutive shots, each with a different exposure level. One. with a normal level, another. for the brightest part of the scene, and the third. for the darkest. The best parts of each exposure are combined into a single high dynamic range frame. HDR is especially useful in challenging lighting conditions such as harsh bright backlights.

The images below clearly show how the HDR function works.

In the first photo (left), the shutter speed was balanced for the best shot of the subject in the foreground. This made the sky overexposed or just too bright. In the image on the far right, the exposure has been balanced to best represent the sky. This made the object too dark. HDR will blend all three frames to enhance detail and present them in bright and midtones.

As you can see, HDR took the best parts of the overexposed and underexposed shots and combined them with the third shot taken at normal exposure. This made it possible to get a detailed photo (it is located in the center) with high contrast.

The sophisticated displays of Apple gadgets are capable of displaying a wide color gamut. Cameras of THESE devices can also create it. They allow you to increase the dynamic range of HDR images by 60%.

Auto HDR on iPhone X, iPhone 8 and 8 Plus

On iPhone X, iPhone 8 and 8 Plus and newer, this feature is enabled by default in iOS. The latest smartphones from Apple are actively using HDR Not only on the rear cameras, but also on the front cameras, when the device considers it possible to improve the photo. But this behavior of the iPhone can be turned off. The Auto HDR switch can be set to inactive in the camera settings (Settings → Camera app), in the HDR section.

As mentioned above, devices such as the iPhone XS, iPhone XS Max, and iPhone XR have improved camera sensors and chips to create better HDR. Based on THESE benefits, Apple has created an even more advanced version of Auto HDR. It’s not for nothing that it got the name Smart HDR.

Smart HDR on iPhone XS, iPhone XS Max and iPhone XR

Smart HDR activates by default whenever needed to improve image quality based on shooting conditions. Unlike previous HDR modes, this smart one works with more scene types. Some of them could not use traditional HDR: “Portrait” and “Portrait Lighting” modes, panoramic and burst shots, live photo and other similar real-life scenarios.

All HDR-embedded images taken on iPhone X or later are marked with the HDR Icon in the very corner. On the iPhone XS, iPhone XS Max, and iPhone XR, Smart HDR is involved in almost all images, but the icon at the bottom of the photos appears only if it is significantly processed.

Below is an example with two different Apple devices to showcase Smart HDR image enhancement with faster sensors, better chips, and improved processing algorithms for newer devices.

Left: Auto HDR on iPhone X; Right: Smart HDR on iPhone XS. Notice the overexposed clown in the photo with Auto HDR.

The difference is obvious. The image on the iPhone X is clearly disrupted in tricky lighting, but the image on the iPhone XS looks much better. This happened precisely due to Smart HDR. Note the possibility to read the Shelton Theater inscription on the back of the clown’s mouth. But you can also turn off Smart HDR in the camera settings, so as not to use this function every time you press the shutter button in the Camera app. To manually control HDR, do the following:

On iPhone XS / XS Max / XR, turn off Smart HDR in Camera → Settings.
On iPhone X / 8/8 Plus, turn off Auto HDR in Camera → Settings.
On previous models, turn off HDR in Camera → Settings.

On all iPhone models that support HDR, this function can be controlled directly in the Camera app, not in Settings. To do this, in the top panel, you just need to click on the HDR icon and select the On or Off mode.

All iPhone models introduced with the iPhone X always save a normal exposure image in the Photos app along with its HDR counterpart. This is because the technology has not yet been fully developed, and the photos were not always perfect. Of course, storing two versions of a photo at once, normal and HDR, doubles the amount of memory required for each shot.

If the issue with the availability of free space is relevant, then you can save only the version with HDR, abandoning the source. To do this, go to Camera → Settings and enable the “Leave original” option. And the latest iPhones with advanced chips and sensors, such as the iPhone XS and above, by default do NOT save the image at normal exposure along with the HDR version of the image.

In fact, this is the main thing to know about HDR on iPhone.

Sources:

http://turbocomputer.ru/nastrojki/chto-oznachaet-HDR-v-nastrojkah-kamery
http://reshu-otvet.ru/chto-oznachaet-HDR-v-nastrojkah-kamery/
http://yablyk.com/992077-what-is-HDR-in-iphone-camera/