Image contrast enhancement based on histogram smoothing and continuous intensity relocation

Image contrast enhancement is a fundamental and important pre-processing stage in the application of image processing techniques. Among revenues of possible approaches, histogram equalization is a popular and attractive candidate method to produce resultant images of increased contrast. However, images obtained from canonical histogram equalization frequently produce artefacts and give rises to uncomfortable viewing particularly in homogeneous regions. In this work, the problem is tackled using the histogram matching concept where the intensity histogram of the input image is matched to its smoothed version for contrast enhancement. Furthermore, pixel intensities are randomly perturbed for a remedy of artefacts. The resultant image intensities are thus distributed over the available range and an increased image contrast is derived. Satisfactory results are obtained from experiments using a collection of outdoor scenery pictures to verify the effectiveness of the proposed approach.