Improved correction for hot pixels in digital imagers

Abstract

From extensive study of digital imager defects, we found that “Hot Pixels” are the main digital camera defects, and that they increase at a nearly constant temporal rate over the camera's lifetime. Previously we characterized the hot pixels by a linear function of the exposure time in response to a dark frame setting. Using a camera with 55 known hot pixels, we compared our hot pixel correction algorithm to a conventional 4-nearest neighbor interpolation techniques. We developed a new “moving camera” method to exactly obtain both the actual hot pixel contribution and the true undamaged pixel value at a defect. Using these calibrated results we find that the correction method should be based on the hot pixel severity, the illumination intensity at the pixel, camera parameters such as ISO and exposure time, and on the neighboring pixels' variability.