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

Abstract

We develop UHD-2/8K cameras capable of high-speed recording at 120 frames/sec or more to support the highest video format of ultrahigh definition television and for shooting slow-motion video. Previously, we developed a 1.25-in. 3-CMOS UHD-2/8K 240-frames/sec high-speed camera system capable of capturing smooth slow-motion video at one-fourth speed. In this article, we describe a multi-functional high-speed 8K camera system with significantly upgraded functionality, compared with the conventional UHD-2/8K 240 frames/sec camera system. The upgraded high-speed camera has three new features. The first feature is a 480-frames/sec 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 on conventional hardware and was output in YCbCr 4:2:0 format. The second feature is a 120-frames/sec random-noise-reduction shooting mode. We applied the multisampling 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-frames/sec flicker reduction mode. We generated an image with an exposure time of 1/100 sec by combining three successive frames of short- (1/600 sec), long- (1/150 sec), 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 .