Image contrast enhancement using fuzzy logic based histogram equalization techniques

Abstract

Nowadays devices are able to capture and process images from complex surveillance monitoring systems or from simple mobile phones The visual quality of the most recorded or captured images are inevitably degraded during the image acquisition process because of inadequate lighting and incorrect setting of the aperture or the shutter speed or both Deficiencies in the image acquisition process often result in low contrast images which normally contain noisy backgrounds In addition there are several reasons for an image video to have poor contrast the poor quality of the used imaging device lack of expertise of the operator and the adverse external conditions at the time of acquisition These effects result in under utilization of the offered dynamic range As a result such images and videos may not reveal all the details in the captured scene and may have a washed out and unnatural look Contrast enhancement targets to eliminate these problems thereby to obtain a more visually pleasing or informative image or both This thesis focuses to solve the above mentioned problems and proposes three methodologies for fast image contrast enhancement methods The proposed methods are based on Histogram Equalization HE for handling gray level and color images