SAMSUNG

Details on the new ISOCELL GN1 sensor

In May, Samsung, as expected, introduced the 50 megapixel image sensor for ISOCELL GN1 smartphone cameras. As the manufacturer said then, the 50-megapixel sensor will allow for brighter images and faster autofocus, and is the first to implement Tetracell and Dual Pixel technologies. Now, Samsung has published a video and details about this curious sensor.
As usual today, GN1 uses Quad Bayer technology (Tetracell in Samsung terminology): unlike conventional RGB sensors, in which pixels with different color filters are arranged in a mosaic pattern, Samsung Tetracell pixels with the same color filters are arranged side by side in groups of four. In bright light, the sensor receives an image close to 50 megapixels and, when there is a lack of light, neighboring pixels are combined in a 2 × 2 matrix to produce diodes. 2.4 μm with the resulting 12.5 megapixel image.
One of the main indicators of the cameras is the speed of focus on the subject. Fast autofocus will help you not miss a precious moment - for that, the ISOCELL GN1 sensor uses Dual Pixel technology with 100 million units of phase detection focus. Each pixel in ISOCELL GN1 consists of two photodiodes that receive light rays from a microlens placed at the top of the pixel. Then, in the automatic focus process with deduction of the phase difference, two “copies” of the incident light image are created, one in each photodiode, evaluated by the sensor. After that, the lens is adjusted until the two images become identical - meaning that the object is in perfect focus. The technology also allows you to improve quality using HDR technology in real time: instead of combining multiple photos, each pixel in a cluster of four takes a photo with a different exposure time: two pixels are photographed with an average exposure time, one with a long exposure and one with a short one. The result is a photo in a range of colors stretched across a frame.



This autofocus is much faster than traditional contrast analysis systems. In addition, the speed of the process depends on the number of pixels with phase detectors installed on the sensor. On many smartphones, the number of pixels with phase detection support is only 5 to 10%, but ISOCELL GN1 uses two photodiodes per pixel.
The sensor, of course, uses Samsung's innovative pixel isolation technology, the Samsung ISOCELL Plus, which uses a physical barrier that allows microlenses to direct more light to photodiodes. As a result, color accuracy is improved and photosensitivity, which means that rich, vivid colors are provided.
Finally, unlike traditional image sensors, GN1 does not have one, but two “native” ISO values: low and high. Thanks to this, it guarantees precise operation in bright conditions and Smart-ISO technology selects the ideal conversion factor for various conditions. This allows you to choose the most optimal dynamic range and reduce noise.Therefore, when shooting portraits on the beach on a sunny day, the technology selects a low value of its own ISO sensitivity to increase the full capacity of the potential well and expand the dynamic range of the image to bright parts of the scene. And when taking a selfie with friends at a party at the end of the night, Smart-ISO technology selects a higher native ISO for optimal brightness with less noise.

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