We are developing 8K cameras capable of high-speed shooting at 120 fps or higher in order to support the highest video format of ultra-high-definition television and shoot slow-motion video. In 2018, we developed a 1.25-in 3-CMOS 8K 240-fps high-speed camera system capable of capturing a smooth slow-motion 8K video at 1/4 speed and used it in the 8K live production of a global sports competition. In this paper, we report a 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 is 480-fps shooting, which is twice the conventional frame frequency. The second is random noise reduction at 120-fps shooting. The third is reduction of flicker that occurs when shooting at 120-fps in areas with a utility frequency of 50-Hz.
In the first feature of the 480-fps shooting mode, we achieved twice the frame frequency of a conventional camera system by operating the analog-to-digital converter (ADC) at twice the speed in the image sensor. The video signal was processed in GBR 4:2:0 format for processing on conventional hardware, and finally the video signal was output in YCbCr 4:2:0 format. The slow-motion replay server was also upgraded to support YCbCr 4:2:0 video format at 480 fps and could generate smooth 1/8-speed 8K slow-motion video.
In the second feature of 120-fps random-noise-reduction shooting mode, we applied the multi-sampling technique to reduce random noise in the image sensor. This technique can reduce the random noise caused by the readout circuit after the pixel via the multi-sampling integration function in the ADC. By using this function, the signal-to-noise ratio of this camera was improved by approximately 3 dB.
In the third feature of the 120-fps flicker reduction mode, we generated an image with an exposure time of 1/100 s by combining the three successive frames of short- (1/600 s), long- (1/150 s), and short-exposure-time images to suppress the 20-Hz flicker caused under the illumination with a utility frequency of 50-Hz. From the experimental results, it was found that the flicker could be reduced to 1/8 or less.
We plan to use the camera for various 8K content productions including international sport competitions.
Technical Depth of Presentation
Fundamental or intermediate.
What Attendees will Benefit Most from this Presentation
Engineers and producers of television and film, Engineers of camera manufacturers
Take-Aways from this Presentation
This camera is the highest resolution high-speed camera capable of capturing slow motion video and supports frame frequencies up to 480-fps. In addition, taking advantage of the high-speed operation of the image sensor, we introduced new technologies such as multi-sampling noise reduction and reduction of flicker caused by 100Hz lighting at frame frequency of 120-fps operation.