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Proceedings Paper

A proposal of sensor-based phase detection method in 3-CMOS 8K 240-fps imaging
Author(s): Kodai Kikuchi; Toshio Yasue; Ryohei Funatsu; Kohei Tomioka; Tomoki Matsubara; Takayuki Yamashita
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Paper Abstract

Focusing difficulty has become a critical issue in 8K ultra-high definition television (UHDTV) production. Especially in 8K high-speed shooting, defocus blur significantly degrades a user's experience of slow-motion playback video. For this reason, incorporating a sensor-based phase detection autofocus (PDAF) system that can adjust the focus of a lens quickly into an 8K UHDTV camera has been strongly desired. Although conventional sensor-based PDAF systems have been designed for single-chip cameras capable of using optional color filters, the application of phase detection (PD) in professional broadcasting cameras with three-chip imaging has not been studied, in which incident light separates into three color components (red, green, and blue) by a separation prism. This paper presents an investigation into the PD property among the color channels using a newly prototyped 1.25-inch 8K 240-fps complementary metal-oxide-semiconductor (CMOS) image sensor with two types of horizontal PD pixels (left- and right-phase). Our experiment showed that crosstalk over angler responses of the PD sensor became larger as the wavelength of light increased, and that the crosstalk in each color component reduced the accuracy of the PD amount between a set of stereo images. Consequently, these results demonstrated that utilizing the phase-differential information from the blue component enables a high-precision sensor-based PDAF operation in three-CMOS imaging when shooting black and white objects

Paper Details

Date Published: 21 February 2020
PDF: 9 pages
Proc. SPIE 11305, Ultra-High-Definition Imaging Systems III, 113050V (21 February 2020); doi: 10.1117/12.2545672
Show Author Affiliations
Kodai Kikuchi, NHK Science and Technology Research Labs. (Japan)
Toshio Yasue, NHK Science and Technology Research Labs. (Japan)
Ryohei Funatsu, NHK Science and Technology Research Labs. (Japan)
Kohei Tomioka, NHK Science and Technology Research Labs. (Japan)
Tomoki Matsubara, NHK Science and Technology Research Labs. (Japan)
Takayuki Yamashita, NHK Science and Technology Research Labs. (Japan)

Published in SPIE Proceedings Vol. 11305:
Ultra-High-Definition Imaging Systems III
Seizo Miyata; Toyohiko Yatagai; Yasuhiro Koike, Editor(s)

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