Dynamic recursive subimage histogram equalization algorithm for image contrast enhancement

Contrast enhancement plays a fundamental role in image processing. Histogram equalization is a well-known and effective technique for enhancing the contrast of the input image, however it fails to preserve the brightness of the image. In order to preserve natural appearance and brightness of enhanced images, we propose a new dynamic recursive sub-image histogram equalization method for contrast enhancement. Experimental results show that, for the variety of test images, the proposed method enhances contrast effectively, while preserving brightness and natural appearance.

I. Introduction

Image processing has many applications in everyday life tasks, from medicine to industry [1]–[4]. It includes all operations applied to digital images that change the photometric or structural characteristics of the image. Image contrast enhancement represents an important stage in almost every image processing system. The aim of image contrast enhancement is to improve the perception of information in images for human viewers, or to provide better input for other automated image processing techniques. The need for the contrast enhancement is necessitated because of the limited capabilities of the hardware used for capturing the image, the uneven lighting conditions and other disturbances.