Sanzo Ugawa

A 2.2/3-inch 4K2K CMOS image sensor based on dual resolution and exposure technique

The recent trend in ultra-high-density cameras is running from HD to 4K2K, which will further extend to 8K4K / portable 4K2K. With advancements in device fabrication process technologies, there has been a pressing need for the miniaturization as well as high resolution and high sensitivity in image sensors [1].

Image reconstruction for high-sensitivity imaging by using combined long/short exposure type single-chip image sensor

We propose a image reconstruction method and a sensor for high-sensitivity imaging using long-term exposed green pixels over several frames. As a result of extending the exposure time of green pixels, motion blur increases. We use motion information detected from highframe-rate red and blue pixels to remove the motion blur. To implement this method, both long- and short-term exposed pixels are arranged in a checkerboard pattern on a single-chip image sensor. Using the proposed method, we improved fourfold the sensitivity of the green pixels without any motion blur.

Performance evaluation of high sensitive DRE camera for cultural heritage in subdued light conditions

We proposed a color video generation method for spatio-temporal high resolution video imaging in dark conditions.[1] The method (dual resolutions and exposures(DRE) method) consists of a high sensitive imaging with employing long time exposure and a subsequent spatio-temporal decomposition process which suppresses a motion blur caused by the long time exposure. Imaging step captures RGB color video sequences with different spatio-temporal resolution sets to increase light amount. Processing step reconstructs a high spatio-temporal resolution color video from those input video sequences using the regularization framework. The performance of DRE is regard to the spectral distribution of a subject was evaluated in this study. Firstly, the spectral distribution of a green subject (which is though to be unfavorable from the viewpoint of imaging with DRE) was measured. Secondly, this subject was captured on video with DRE, the peak signal-to-noise ratio (PSNR) of the video images was evaluated. Experimental results showed that the DRE method is effective in regard to green subjects. As for subjects that are commonly seen, their spectral distribution showed a broad shape, and the reconstructed images with DRE had high PSNRs. Moreover, even for the subject with a peaky spectral distribution (such as an LED), PSNR value was high. This is because the spectral characteristic of the color filter used with DRE has a wide crosstalk region across the colors