An Image Processing Pipeline with Digital Compensation of Low Cost Optics for Mobile Telephony

As digital imaging becomes more prevalent in consumer products, the industry strives to reduce the cost and the complexity of imaging solutions and, at the same time, to improve the color quality and resolution of the images. The proliferation of imaging in mobile phones, digital cameras, webcams, toys, etc. creates the need for a low cost, small footprint image sensor. Nowadays, sensor optics account for approximately half the cost of an image sensor system for a camera phone, and their cost does not scale down as fast as the cost of semiconductors. In this paper, we describe the algorithms and the hardware implementation of a novel color processing chain that uses image processing techniques to compensate for the spatial variations in image attributes and quality due to low cost optics. If left uncorrected, these variations produce undesirable visual effects and lead to unacceptable image quality. Besides the correction of artifacts due to lenses, the image processing chain performs a sequence of corrections for real time dead pixel replacement, color correction, filtering, color space transformations for subsequent compression, etc