"Ultrapixel
"The era of megapixels has come to an end"- the head summarized HTC Peter Chow(Peter Chou) during yesterday's announcement of the new flagship smartphone HTC One
, which was equipped with a revolutionary camera with Ultrapixel technology. The Taiwanese company once again confirmed the rule that a large number of pixels does not guarantee picture quality. But what is the revolutionary nature of the transition? from megapixels to "ultrapixels"?
Camera HTC UltraPixel It differs not in the number of pixels, but in their size. Simply put, the pixels are slightly larger than others mobile cameras Oh (2 microns vs. 1.1-1.4 microns). This allows the camera to capture 300 % more light compared to conventional sensors, even the most advanced ones today 13 - megapixel cameras. As a result, the camera is able to take pictures High Quality in any lighting (even insufficient).
Large pixels capture more light
To keep blur to a minimum, HTC uses multi-axis optical image stabilization in both the main and front cameras, resulting in sharper photos. By the way, 2,1 -megapixel front camera is capable of creating video in high resolution 1080p, and the new graphics chip guarantees continuous autofocus at speeds up to 200 ms.
The difference is obvious: HTC One (top), iPhone5 (bottom).
Example of shooting in HDR mode:
Before release HTC One There's only a short time left on sale and we're looking forward to comparing "ultrapixel" camera with Nokia 808 PureView or Nokia Lumia 920. In general, one can only applaud the Taiwanese company’s desire for innovative technologies and refusal "megapixel race".
HTC UltraPixel camera specifications:
- Sensor type: CMOS BSI
- Sensor size: 1/3 inch
- Pixel size: 2mm x 2mm
- Resolution: 2688 x 1520 with 16:9 aspect ratio = = 4MP
- Shutter speed up to 48fps with limited motion blur
- Video resolutions: 1080p up to 30 fps, 720p up to 60 fps, 1080p with HDR up to 28 fps, 768x432 up to 96 fps
- Focal length: 3.82 mm
- Optical F/# aperture F/2.0
- Number of lenses: 5P
- Optical Image Stabilizer: 2-axis, +/- 1 degree (average), 2000 cycles per second
- Maximum fps: up to 8 fps during continuous shooting
Hello, dear users of the best mobile portal Trashbox. HTC used HTC in its flagship smartphone One newest a camera created using the so-called UltraPixel technology. The innovative technology has created a lot of hype both world wide web, and in reality, so today I want to tell you what UltraPixel is and how it works. The most interesting things are waiting for you under the cut.
UltraPixel is a proprietary technology of the Taiwanese company HTC. Currently used in the HTC One and HTC One Mini smartphones, as well as the yet to be announced HTC One Max. The company characterizes UltraPixel as the latest high-quality shooting technology. The photo resolution of the UltraPixel camera in the HTC One and HTC One Mini is “only” 4 megapixels, but the quality of the resulting images is not inferior to the 8- or even 13-megapixel sensors that are installed in competing flagship smartphones. It's all about the same UltraPixel technology, which I will tell you about in detail below.
Most of the main cameras in mobile devices ah works with the so-called Bryce Bayer filter: a three-color filter is located on top of the sensor, transmitting information about the overall light intensity to each photosensitive element. At the same time, due to slight vibration in the geometry of the filter elements and sensors, the photograph at 100% magnification turns out to be somewhat blurry and even unnatural. A side effect of the Bayer array is the need to use an anti-aliasing filter. It is used to reduce color artifacts.
The operating principle of the matrix with UltraPixel technology is based on a different structure. It uses a Bayer filter, but the surface of the photosensitive elements is increased. Elements in one layer are sensitive to blue, in the second to green, and in the third to red. The area of the sensors is approximately three times larger than in the cameras of other mobile devices - four square macrometers. 
In theory, those same four square macrometers allow the camera to receive 300% more light. The more information a pixel captures, the more reliable information about the objects being photographed it transmits to the photo processor. Comparisons of cameras with different optics have been carried out more than once, and the difference is especially noticeable in photographs taken in low light conditions. 
According to HTC, there is simply no point in increasing the resolution of photos if their quality remains unchanged. The resolution of photos taken with the UltraPixel camera is 2688x1520 - this is enough to view them on your smartphone, tablet or laptop. If additional processing or cropping is applied to the image, the resolution may not be sufficient.
The increased pixel sizes in the UltraPixel camera sensor are one of the other components that affects the quality of the photo. The most sensitive camera contains key ImageSense components, including: UltraPixel matrix - has larger pixels, which allows you to capture 300% more light; HTC ImageChip - provides automatic focusing, noise reduction, color tone compensation and realistic dynamic range; F/2.0 aperture - is the widest aperture among all available smartphone cameras, transmitting 44% more light; Optical image stabilization - reduces blur and distortion in videos shot without using a tripod.
In 2013, the HTC One smartphone was released. Among other advantages, the device was equipped with a non-standard camera, which used technology called Ultrapixel. The Taiwanese manufacturer called the introduction of ultrapixels a breakthrough in the field of mobile photography, since thanks to this event, other manufacturers will finally stop measuring the quality of smartphone cameras using the number of megapixels.
Photosensitive elements in conventional cameras
First, let's take a brief look at the principle of arranging light filters on a matrix according to the Bayer scheme, which is used in almost all mobile photographic modules. The matrix contains light-sensitive elements. They are called "sensels". These elements capture light, converting it into electrical charge. Each senseel can perceive one color - blue, green or red.
The disadvantage of the Bayer array of color filters is the appearance of color artifacts and moire in the photo. To correct the situation, they use a special anti-aliasing filter, which makes the images appear slightly blurred (hence the name “point-and-shoot”). This is clearly visible when changing the scale of photographs taken with amateur cameras and mobile photo modules.
In fact, most smartphone manufacturers try to cram as many pixels onto the sensor as possible in order to increase the native resolution of the resulting photo. As the number of megapixels increases, the area of each pixel decreases. As a result, they become less sensitive to light, photographs turn out darker, and noise appears on them. To compensate for the lack of received illumination, the aperture is opened wider, and to combat noise, they use the combination of neighboring pixels.
The essence of UltraPixel technology and its advantages
HTC approached the issue of improving the camera from the other side: they reduced the resolution to 4 megapixels, but turned the pixels into ultrapixels, increasing their size to 2 micrometers, versus 1.1 micrometers (microns) in 13 megapixel sensors.
UltraPixel technology involves placing sensors on a photo matrix in three layers, each of which separately perceives red, blue and green colors. At the same time, the area of the photosensitive elements is 3 times larger (up to 4 µm square) in relation to “ordinary” sensors.
A similar principle has long been used in Foveon matrices, with which Sigma DSLRs are supplied.
In fact, this solution has several advantages:
- ultrapixels perceive approximately 300% more light, which means you can get better photos in the dark;
- significant reduction in noise when shooting in low light conditions;
- moving people and objects in the resulting photo are practically not blurred;
- thanks to a wider HDR range, dark areas are highlighted, and light areas, on the contrary, are not overexposed;
- There is no need for an anti-aliasing filter, which causes blurring in the Bayer matrix.
Disadvantages of UltraPixel technology
Theoretically, this idea has a lot of advantages. However, the main mistake was the decision to stop at 4 megapixels. Because of this, when shooting distant objects and landscapes, photographs suffer from low detail.
But why only 4 megapixels, isn't there more? Of course you can. However, it is worth considering that ultrapixels will require much more space than “regular” ones. Accordingly, the physical size of the photomatrix will “grow” in size, and with it the module itself. The mass consumer is accustomed to the small, compact camera eye in smartphones, so not everyone will appreciate the sudden change in its diameter. Therefore, at HTC, when introducing UltraPixel, they decided to limit themselves to a lower resolution for the sake of the design of the mobile device case.
Perhaps in the future, camera phones will be equipped with a much larger matrix than today, where ultrapixels will be used instead of “regular” pixels.
Where else are ultrapixels used?
The word “UltraPixel” was coined by HTC marketers, who for the first time tested the technology of increasing pixels on the camera sensor in a smartphone. The idea turned out to be promising, and later found application in Apple devices (iPad Air 2), as well as Google, which together with LG and Huawei released the Nexus 5X and Nexus 6P. The name UltraPixel never caught on, so it is not used in descriptions of the characteristics of these devices.
Samsung later showed at the exhibition new smartphone- Galaxy S7 edge, with a matrix size of 1/2.5”, and increased pixels to 1.4 microns. For reference: in the Galaxy S6, the size of the 16-megapixel photo matrix is 1/2.6″, and each pixel is 1.2 microns.
If you look at these example photos taken with the Note 5 (left) and the Galaxy S7 (right), it looks like both photos are about the same quality.
However, with a 100% magnification of individual fragments, a significant difference in detail is immediately visible.
Enlarged pixels are used in professional-level photographic equipment, that is, in DSLRs. Thanks to this, even the most affordable SLR cameras with a standard (included) lens are significantly ahead of fairly cool point-and-shoot cameras when shooting in low light conditions. They capture more light, and the resulting images tend to have less noise. If the pixel density in DSLRs was the same as in conventional compact cameras, as well as smartphones, the resolution would exceed 120 megapixels. Meanwhile, the most sophisticated models on this moment can shoot with a resolution of 36, maximum 51.4 megapixels.
The difference between shooting in low light between cameras with large pixels and regular ones
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One of the “killer features” of the new product is its camera with “ultra-pixels”, which, according to HTC, will give odds to any 13 megapixel cameras installed on competitors’ smartphones. Let's try to analyze in detail the features of this “ultrapixel” camera.
The new HTC ImageSense technology implemented in HTC One consists of an UltraPixel Sensor, a new ImageChip processor, optics with a maximum aperture of f/2.0 and a two-axis Optical Image Stabilization system.
The UltraPixel Sensor features larger pixels and captures 300 percent more light than typical 8MP and 13MP cameras. The physical size of the UltraPixel Sensor is 1/3”, and the size of the “ultrapixel” is 2 microns. But in a camera with a resolution of 8 and 13 megapixels, which is equipped with a 1/3” sensor, the pixel size is 1.4 and 1.1 microns.
According to HTC, instead of filling the area with smaller pixels, they filled it with larger pixels. Comparison of pixels in the picture below.
The new video signal processor has expanded the capabilities of the HTC ImageChip function. The main innovation can be considered a reduction in the required time to check the distance. This now requires no more than 200 ms.
The next innovation is a wider HDR range. In HDR mode, HTC One can shoot video at 1080p resolution.
In the picture above, HTC shows the superiority of the HTC One camera over Samsung cameras(f/2.6) and Apple iPhone 5 (f/2.4), which shoots better in low light conditions.
HTC notes that the HTC One smartphone camera captures images at maximum resolution in just 1/48 s. The HTC One X and competitors in this price range are characterized by 1/30 sec.
The dual-axis Optical Image Stabilization system makes photos clear and the camera immune to shaky hands.
Examples of photos and videos taken with the HTC One camera can be viewed.
It looks like HTC marketers will no longer worry about finding out from announcements how many tens of megapixels the camera in competitors' smartphones contains. As you know, in the new flagship model the company has used a fresh design HTC solution UltraPixel - “ultrapixels”.
According to the Taiwanese, the principle “the more the better” regarding megapixels in cameras ceases to work, because the new UltraPixel camera with an actual resolution of 4 megapixels in terms of shooting quality will give odds to any used in modern smartphones 8 or even 42 megapixel solution. The One's camera sensor uses a relatively small number of pixels ("ultrapixels"), but they are capable of capturing more light than standard smartphone cameras. According to Simon Whitehorn, HTC's director of special projects, "Megapixels are nothing more than a metric used by vendors to represent camera performance, and is not always used in the right context."
The HTC One camera is built on a fairly standard 1/3-inch back-illuminated CMOS sensor, and its main feature is the pixel size, which is 2 micrometers (microns) on one side, which is significantly larger than modern 8-megapixel mobile cameras with a pixel size of 1.4 micrometers, as in the iPhone 5 and Samsung Galaxy S III or 1.1 micrometers, as in HTC Butterfly.
So-called “ultrapixels” are capable of capturing on average 200% more light, and when compared with 13-megapixel cameras, where the pixel size is 1.1 micrometers, the difference can reach 300%. It is the small pixel sizes that lead to the appearance of grain and noise in photographs when shooting in low light conditions. Of course, 2 micrometer pixels can be used in cameras larger than 4 megapixels, but this will lead to a significant increase in lens size, as in some Nokia smartphone models.
In order to capture the sensor more light, the HTC One smartphone is equipped with an f/2.0 lens with ISO sensitivity ranging from 100 to 1600, which also has a positive effect on shutter speed.
Test photos taken with the HTC One by Wired reviewers in a dimly lit restaurant turned out to be significantly clearer than those taken with the Samsung Galaxy S III. The only good thing about photos taken with the Galaxy's 8-megapixel camera was that you could zoom in on the photos, but that certainly didn't make them any lighter.
Thanks to ultrapixels, the work of the ImageChip 2 post-processing chip has also been simplified, which no longer needs to deal with noise as much as before, and HTC developers were able to use its computing capabilities for other new functions.
One of the most interesting innovations here is the Zoe mode, which allows the user to record video in maximum resolution while simultaneously taking continuous photographs. According to HTC representatives, they were able to develop a dual encoding algorithm, which made it possible to simultaneously shoot photos and videos without losing data and, accordingly, quality. In practice, this means that the user can return to previously captured video content, select the desired frame and save it as a full-fledged photo. It's important to note that in Zoe mode, the device starts recording video before you even press the record button, which will help you avoid missing important moments.
In addition, for video shooting in Full HD and Slow motion formats, the option of a constantly activated HDR mode is available, and thanks to a special gyroscope HTC camera One, similar to the Nokia Lumia 920, implements multi-axis optical stabilization. Unlike digital stabilization, this provides for movement of the lens itself within a millimeter to compensate for hand shake or movements during movement.
Front-camera HTC One has a 2.1 megapixel sensor resolution, supports HDR and is equipped with an ultra-wide-angle (88 degrees) lens, which was first used in the HTC 8X model.
Having finished taking photos and videos, the owner of One turns to the updated Living Gallery, where instead of a chaotic set of thumbnails, an organized catalog of events awaits him. Photos and videos are available for a 30-second preview, and you can apply filters, add music, and other editing techniques.
HTC smartphone One and its UltraPixel camera became the first solutions in the world of mobile devices when the manufacturer, at its own peril and risk, decided to abandon the use of the term “megapixels” in favor of a new, as yet unknown concept. Will this experience be successful?