Color compensation of histogram equalized images

Abstract

We present a color correction algorithm for histogram equalized images captured by a digital camera. Current color correction methods are based on human color perception of luminance and hue. However, these techniques do not consider nonlinear camera characteristics, therefore the resulting color images show color distortions where brightness modification is severe. We propose a new effective color correction method that depends on the camera brightness and color curve. It utilizes the relationship of luminance and color variation of a camera used for image capture. We can predict chrominance variation after luminance change by tracing the brightness-chrominance curve of the camera model. Therefore the resulting image shows color that would have been obtained at different exposure using the same camera. We verify that the processed images have natural color and that they are similar to images taken at different exposure conditions. Moreover it is possible to apply the proposed method to software bracketing; we can change the exposure condition of an image at post processing stage. All test results demonstrate that our method is accurate and useful in the enhancement of a color of digital images. © 2009 SPIE-IS&T.