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Sensors 2017, 17(2), 293;

G-Channel Restoration for RWB CFA with Double-Exposed W Channel

Yonsei University, Deptartment of Electrical and Electronic Engineering, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
Author to whom correspondence should be addressed.
Academic Editor: Fabrizio Lamberti
Received: 6 December 2016 / Revised: 26 January 2017 / Accepted: 30 January 2017 / Published: 5 February 2017
(This article belongs to the Section Physical Sensors)
Full-Text   |   PDF [4610 KB, uploaded 5 February 2017]   |  


In this paper, we propose a green (G)-channel restoration for a red–white–blue (RWB) color filter array (CFA) image sensor using the dual sampling technique. By using white (W) pixels instead of G pixels, the RWB CFA provides high-sensitivity imaging and an improved signal-to-noise ratio compared to the Bayer CFA. However, owing to this high sensitivity, the W pixel values become rapidly over-saturated before the red–blue (RB) pixel values reach the appropriate levels. Because the missing G color information included in the W channel cannot be restored with a saturated W, multiple captures with dual sampling are necessary to solve this early W-pixel saturation problem. Each W pixel has a different exposure time when compared to those of the R and B pixels, because the W pixels are double-exposed. Therefore, a RWB-to-RGB color conversion method is required in order to restore the G color information, using a double-exposed W channel. The proposed G-channel restoration algorithm restores G color information from the W channel by considering the energy difference caused by the different exposure times. Using the proposed method, the RGB full-color image can be obtained while maintaining the high-sensitivity characteristic of the W pixels. View Full-Text
Keywords: G-channel restoration; red–white–blue color filter array; multispectral image sensor G-channel restoration; red–white–blue color filter array; multispectral image sensor

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Park, C.; Song, K.S.; Kang, M.G. G-Channel Restoration for RWB CFA with Double-Exposed W Channel. Sensors 2017, 17, 293.

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