Digital imaging devices commonly employ two types of image sensors: charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS). While CCDs have been the dominant technology in the past, CMOS sensor-based imaging devices have rapidly gained a market share. One key distinction between the two is the method by which images are captured. CCD devices employ a global shutter, where each pixel of an image is captured concurrently. In contrast, CMOS sensors typically utilize a rolling shutter, where the pixels in an image are captured row-by-row sequentially from top to bottom. The rolling shutter has traditionally been considered detrimental to image quality, because pixels in different rows are exposed to light at different times, which often causes skew and other image artifacts, especially for moving objects. This technology describes a method of improving CMOS imaging techniques by controlling the readout timing and exposure for each row of sensors. This technology thus allows the user to perform high speed imaging, remove motion blur due to instrument instability, and skew compensation.
This technology proposes a readout architecture for CMOS image sensors called coded rolling shutter. The technology takes advantage of the characteristic exposure discrepancy between different parts of the camera lens. By controlling the readout timing and exposure length for each row of the pixel array, one can flexibly sample the 3D space-time volume of a scene and take photographs that effectively encode motion and dynamic range information within a single 2D image. These coded images are useful for many applications in digital photography and computer vision.
The technology has been tested on several instances of blurred and unclear images. The images either required one or more of optical flow and interpolation, motion-deblur, high-speed photography, high dynamic range imaging, or single-shot skew-free video. This coded rolling shutter technology produced clear images from all of the blurred ones.
Tech Ventures Reference: IR M10-039
