Mobile Imaging Black Technology: DRAM Makes Your Video | 'Slow' | Down

Here are two terms to explain first, one is CMOS (Complementary Metal Oxide Semiconductor), that is complementary metal oxide semiconductor, in the field of digital imaging is called a photosensitive element. Digital camera imaging principle is: Light through the lens projection The surface of the photosensitive element, the light is decomposed into different shades of light by the filter on the surface of the photosensitive element, the colored light is perceived by the photosensitive cells corresponding to each filter, and generates analog current signals with different intensities. These signals are then collected by the circuit of the photosensitive element. The analog signal is converted into a digital signal by a digital-to-analog converter and then processed by an image processor. The signal is then transferred to a memory card and stored as a picture that we see in a cell phone camera. Larger, the better the imaging effect is. This is the origin of the 'big-by-one-dead-people' that is circulating in the camera circle.

The second is DRAM (Dynamic Random Access Memory), which is a dynamic random access memory. DRAM can only hold data for a short period of time. In order to maintain data, DRAM uses capacitor storage, so it must be refreshed at intervals, if the storage unit is not Refresh, the stored information will be lost. Common DRAM is the computer's running memory, which is what we often say memory. The role of DRAM for the computer is used to temporarily store the calculation data in the CPU, and with the hard disk and other external Memory exchange data.

The CMOS embedded DRAM cache helps imaging similar to that used in computers. DRAM is used to store captured high-speed image information and output at the optimal rate of the sensor interface. Through the DRAM cache, the performance of CMOS can be fully squeezed. It solves the problems such as the uncomfortable speed of the continuous shooting of the mobile phone, poor video quality, and low video frame numbers. The most intuitive improvement to the user lies in the ability to use mobile phones to take slow-motion video at 960 fps, and can be reduced accordingly. The jelly effect produced when shooting high-speed moving objects greatly improves the imaging effect.

And not only in terms of video, but also for shooting ordinary still photos, DRAM is also very useful. Specifically to the Sony IMX400 this world's first embedded DRAM cache CMOS image sensor, it can be read in 1/120 seconds A 19.3 million-pixel still photo. This means that when you press the camera button, the image sensor CMOS of the mobile phone can capture and cache multiple pictures via DRAM, and after being synthesized by image processing in the background, An image with the best image quality. Early HDR photographs were achieved using this principle. By taking an overexposure, an underexposure, and a normal exposure of three photographs, they were combined to achieve optimal results. Best exposure. At that time, it took a long time to take a HDR photo without the help of DRAM cache. Now, with the help of DRAM, it is easier to take HDR photos.

In short, for CMOS with embedded DRAM cache, it is equivalent to a lot of functions from scratch. It is believed that with the advancement of technology, more and more mobile phones will carry similar CMOS image sensors. Share slow-motion video, shoot more Good effect photo, Technology inadvertently changes our life.