Samsung has announced the next generation of its 50 megapixel sensor called ISOCELL GN2. It follows last year’s GN1 and promises significant autofocus improvements thanks to a new phase detection advancement that the company calls ‘Dual Pixel Pro’.
Dual Pixel is a technology that is mostly associated with Canon cameras and divides a pixel so that it can detect a phase change per pixel rather than relying on alternating phase detection pixels on the sensor, leading to the loss of image quality since the pixels are not used to capture image data.
As Canon puts it:
Each pixel on the CMOS image sensor has two separate, light-sensitive photodiodes, which convert light into an electronic signal. Independently, each half of a pixel detects light through separate micro-lenses, on top of each pixel. During AF detection, the two halves of each pixel – the two photodiodes – send separate signals that are analyzed for focus information. A moment later, when a real image or a video frame is recorded, the two separate signals of each pixel are combined into one single image, to capture the image. It improves the AF speed in most of the area you focus on. The result is phase detection autofocus, which examines the scene and not only recognizes whether a subject is in focus or not, but in which direction (near or far) and how much.
Samsung says the concept is similar to how human eyes work. Each eye sees slightly different versions of the same scene and focuses by comparing the two differences and finding the mean. Similarly, phase detection works by comparing the phase differences in images generated by pixels that look left and right, allowing the camera to calculate the focus distance or the location where the two phases are aligned.
With this first generation Dual Pixel autofocus, the pixel is split in the middle. In Dual Pixel Pro, the distribution is shifted diagonally so that pixels can not only see phase differences between the left and right sides of a pixel, but also top and bottom.
“Dual Pixel Pro takes autofocus to a new level,” Samsung writes. ‘It uses green pixels that divide photodiodes with diagonal structures. These diagonally split pixels compare the phase differences between the top and bottom of the pixel, in addition to phase differences on the left and right sides. ”
The result is a sensor that has faster and more accurate autofocus in more conditions. According to Samsung, the focus in low light or on fast-moving subjects makes it even more reliable and addresses the limitations of the original Dual Pixel technology.
Dual Pixel Pro technology uses 100 million phase-detecting photodiodes that detect phases vertically and horizontally for faster and more accurate autofocus.
“Dual Pixel technology … struggles to distinguish between the left and right sides of patterns such as parallel horizontal stripes,” Samsung explains. “The addition of top and bottom phase detection means your camera can better distinguish these patterns so it can grab focus quickly, even if your subject is wearing a patterned shirt with horizontal lines.”
The new sensor can also create 100-megapixel images.
“In 100MP mode, the GN2 accurately arranges the color pixels using an intelligent re-mosaic algorithm, which creates three individual layers of 50MP frames in green, red and blue,” says Samsung. “These frames are then enlarged and merged to produce a single ultra-high 100MP resolution photo.”
The GN2 can also enhance its dynamic range with what Samsung describes as a ‘long jump HDR’ feature. It uses shutters over the same pixel arrays to capture multiple frames of short, medium and long exposure in one image. It is an adaptation to the real-time HDR mode on previous sensors that need to be active for longer, and consequently this new HDR technology reduces the energy consumption of the sensor by 24%.
As expected, the GN2 uses Smart ISO Pro, a technology the company announced earlier in February. You can read more about Smart ISO Pro here, but in short, it is a technology that intelligently sets the conversion gain of a sensor and creates a finished image by taking readings of both high and low ISO to instantly take photos creating a high dynamic range with fewer motion artifacts.
Finally, the GN2 can record 1080p Full HD videos at up to 480 frames per second and 4K videos can shoot as fast as 120 frames per second, which matches the speed of top quality cameras.
Samsung says that the ISOCELL GN2 is currently in mass production, which means that it may appear in new smartphones in the next few months, and one of the obvious candidates is Samsung’s next Note device which will probably come later this year.
(via GSM Arena)