Preventing color artifacts in overexposed regions and preserving maximum signals in near-overexposed regions of digital images

摘要

Distortions in digital image data, for example, radial falloff and improper white balance, are corrected without introducing artifacts in saturated regions or causing near-saturated regions to become saturated. The approach avoids pushing near-saturated colors into saturation by assuring that the total gain applied to a pixel channel is always less than 1. A spatially adaptive clamp threshold is used to clamp color values for a pixel after the color channel color values have been gain-adjusted. In this manner, saturated pixel color values that have been shifted-down into non-saturated regions are clamped to a maximum valid value and are presented as white in images generated from the gain-adjusted image data. One example embodiment may calculate an adaptive clamp threshold for each pixel in the image data. Another example embodiment may calculate an adaptive clamp threshold for each pixel in a row of pixels in the image data.