1.25-inch 3-CMOS Multi-Functional High-Speed 8K Camera System

We are developing 8K cameras capable of high-speed recording at 120-fps or more to support the highest video format of ultra-high-definition television and shoot slow-motion video. Previously, we developed a 1.25-inch 3-CMOS 8K 240-fps high-speed camera system capable of capturing smooth slow-motion video at 1/4 speed. — In this paper, we describe a multi-functional high-speed 8K camera system with significantly upgraded functionality, compared to the conventional 8K 240-fps camera system. The upgraded high-speed camera has three new features. — The first feature is a 480-fps shooting mode. With this, we achieved twice the frame frequency of a previously-developed camera system by operating the analog-to-digital converter (ADC) at twice the speed in the image sensor and subsampling the image. The video signal was processed in GBR 4:2:0 format for processing on conventional hardware and was output in YCbCr 4:2:0 format. — The second feature is a 120-fps random-noise-reduction shooting mode. We applied the multi-sampling technique to reduce the random noise caused by the readout circuit in the image sensor. This technique can improve the signal-to-noise ratio of the camera by approximately 4 dB. — The third feature is a 120-fps flicker reduction mode. We generated an image with an exposure time of 1/100 s by combining three successive frames of short- (1/600 s), long- (1/150 s), and short-exposure-time images to suppress the 20-Hz flicker caused by illumination with a power line frequency of 50-Hz. From the experimental results, it was found that the flicker could be reduced to 1/10 or less.