Patent Number: 7,102,697

Title: Contrast enhancement of digital images

Abstract: An adaptive histogram equalization method is introduced which allows the histogram equalization amount to automatically adapt to the original image contrasts, which can be measured from the originals. Contrast over-enhancement is avoided by limiting the spatial frequency response of the histogram. Besides that, methods to remedy the brightness change problem encountered by histogram equalization are described.

Inventors: Lei; Zhichun (Stuttgart, DE), Sartor; Piergiorgio (Fellbach, DE), Inescu; Yalcin (Hamburg, DE), Wagner; Peter (Waiblingen, DE)

Assignee: Sony Deutschland GmbH

International Classification: H04N 5/52 (20060101)

Expiration Date: 9/05/02018