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Noise Characteristics of a High Dynamic Range Camera with Four-Chip Optical System



Author(s)

Takayuki YAMASHITA and Yoshihiro FUJITA

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DOI:10.17265/2328-2223/2018.02.001

HDR (high dynamic range) imaging has recently been applied to video systems, including the next-generation UHDTV (ultrahigh definition television) format. This format requires a camera with a dynamic range of over 15 f-stops and a signal to noise SN-ratio that is the same as that of HDTV systems. However, current UHDTV cameras cannot satisfy these conditions. We proposed a four-chip capturing method that combines three-chip and single-chip systems. A prism divides incident light into two rays. Most of the incident light is directed to the three-chip capturing block; the remainder is directed to a single-chip capturing block, avoiding saturation. High quality HDR video can then be obtained by synthesizing the images obtained from the two systems. In this paper, we detail this image synthesis method, and analyze the differences between the three-chip and single-chip capturing systems. In particular, we focus on noise analysis of the single chip system. Most of the noises do not affect to image quality but those at around the switching point degrade the visual picture quality. To improve the degradation we propose a new switching method for smooth matching between different noise characteristics of the two systems. Finally, we discuss the results of a simulation used to verify its effectiveness.

HDR, UHDTV, camera, image processing, single-chip imaging.