Adaptive pixel defect correction

Abstract

Although the number of pixels in image sensors is increasing exponentially, production techniques have only been able to linearly reduce the probability that a pixel will be defective. The result is a rapidly increasing probability that a sensor will contain one or more defective pixels. Sensors with defects are often discarded after fabrication because they may not produce aesthetically pleasing images. To reduce the cost of image sensor production, defect correction algorithms are needed that allow the utilization of sensors with bad pixels. We present a relatively simple defect correction algorithm, requiring only a small 7 by 7 kernel of raw color filter array data that effectively corrects a wide variety of defect types. Our adaptive edge algorithm is high quality, uses few image lines, is adaptable to a variety of defect types, and independent of other on-board DSP algorithms. Results show that the algorithm produces substantially better results in high-frequency image regions compared to conventional one-dimensional correction methods.