Stewart Gresty Smith

A CMOS image sensor with a double-junction active pixel

A CMOS image sensor that employs a vertically integrated double-junction photodiode structure is presented. This allows color imaging with only two filters. The sensor uses a 184*154 (near-QCIF) 6-transistor pixel array at a 9.6-/spl mu/m pitch implemented in 0.35-/spl mu/m technology. Results of the device characterization are presented. The imaging performance of an integrated two-filter color sensor is also projected, using measurements and software processing of subsampled images from the monochrome sensor with two color filters.

Fast Noise Level Estimation using a Convergent Multiframe Approach

Image denoising is one of the most recurrent problems to face in the design of image generation pipelines. This paper proposes a novel method for the estimation of the noise level in images contaminated by additive white Gaussian noise (AWGN). The estimated noise level is updated on a frame basis allowing convergence to the optimal value. At the same time, dynamic adjustment to changing noise levels is permitted. The proposed technique has been successfully implemented in a real system, demonstrating the validity of the proposed solution.