High-Speed Line-Scan Camera with Multi-Line CMOS Color Sensor

Abstract

A new camera technology for high-speed color scanning is presented that is based on a novel multi-line CMOS color image sensor. A pixel matrix consisting of multiple red-, green-, and blue-sensitive lines allows acquisition of dense RGB color information at every pixel location including the possibility of improving the signal to noise ratio by summing up multiple exposures in the analog domain of the chip. Therefore, compared to common cameras with Bayer filters, the acquired image data are more robust against color artifacts like Moiré effects. Consequently, images with good quality are possible even at high object speeds, where lighting power may become limiting otherwise. This work describes an algorithm for improving low-light image quality by accumulating multiple exposures acquired by a multi-line color pixel matrix. Furthermore it is shown how this algorithm's implementation is effectively split up into an FPGA part and an image sensor part. Finally, the increase of responsivity due to this algorithm is shown, which is regarded as a key requisite for implementing high-speed cameras.