Samsung announced the next generation of its 50 megapixel sensor called ISOCELL GN2. It follows last year’s GN1 and promises significant improvements in autofocus thanks to a new phase detection advance that the company calls “Dual Pixel Pro”.
Dual Pixel is a technology most commonly associated with Canon cameras and splits a pixel to allow detection of a phase shift per pixel, instead of relying on phase detection pixels interspersed in the sensor, resulting in loss of image quality since those pixels are not being used to capture image data.
As Canon explains:
Each pixel in the CMOS image sensor has two separate, light-sensitive photodiodes that convert the light into an electronic signal. Regardless, each half of a pixel detects light by means of separate microlenses, at the top of each pixel. During AF detection, the two halves of each pixel – the two photodiodes – send separate signals, which are analyzed for focus information. Then, an instant later, when a real image or video frame is recorded, the two separate signals from each pixel are combined into one, for the purpose of image capture. This greatly improves the speed of the AF in most of the area you are focusing on. The result is phase detection autofocus, which examines the scene and recognizes not only whether the subject is in focus or not, but in which direction (near or far) and by how much.
Samsung says the concept is similar to the functioning of human eyes. Each eye sees slightly different versions of the same scene and focuses by comparing these two differences and finding the mean. Likewise, phase detection works by comparing the phase differences in images generated by pixels on the left and right, which allows the camera to calculate the focus distance or the location where the two phases align.
With this first generation Dual Pixel autofocus, the pixel has been split in half. In Dual Pixel Pro, this division is shifted diagonally so that the pixels not only see the phase differences between the left and right sides of a pixel, but also the top and bottom.
“Dual Pixel Pro takes auto focus to a new level,” writes Samsung. “It uses green pixels that divide photodiodes with a diagonal structure. These diagonally divided pixels compare the phase differences between the top and bottom of the pixel, in addition to the phase differences on the left and right sides. “
The result is a sensor with fast and accurate autofocus in more conditions. Samsung says this arrangement makes focusing on low light or fast-moving subjects even more reliable and addresses the limitations of the original Dual Pixel technology.
Dual Pixel Pro technology uses 100 million phase detection photodiodes that sense phases both vertically and horizontally for faster and more accurate autofocus.
“Dual Pixel technology… strives to differentiate between the left and right sides of patterns, such as parallel horizontal stripes,” explains Samsung. “The addition of upper and lower phase detection means that your camera can better distinguish these patterns, making it able to quickly capture focus, even when the subject is wearing a shirt printed with horizontal lines.”
The new sensor is also capable of creating 100 megapixel images.
“In 100MP mode, GN2 painstakingly rearranges colored pixels using an intelligent reclassification algorithm, creating three individual layers of 50MP frames in green, red and blue,” says Samsung. “These frames are then enlarged and merged to produce a single 100 MP ultra-high resolution photograph.
GN2 can also increase its dynamic range with what Samsung describes as a “scaled HDR” feature. It uses rolling shutters on the same pixel arrays to capture multiple frames of short, medium and long exposures in an image. This is an adjustment to the real-time HDR mode on previous sensors that would need to be active longer, and as a result, this new HDR technology reduces the sensor’s power consumption by 24%.
As expected, GN2 takes advantage of Smart ISO Pro, a technology the company announced in early February. You can read more about Smart ISO Pro here, but in summary, it is a technology that intelligently defines the conversion gain of a sensor and creates a final image, taking high and low ISO readings to instantly create high images dynamic range with less movement. artifacts.
Finally, GN2 will allow Full HD 1080p videos to be captured at up to 480 frames per second and 4K videos at up to 120 frames per second, matching the speeds of cutting-edge dedicated cameras.
Samsung says ISOCELL GN2 is currently in mass production, meaning it could start appearing on new smartphones in the coming months, with an obvious candidate being Samsung’s next Note device, due out later this year.
(via GSM Arena)