Normalization of brightness and contrast in video displays

Abstract

The nonlinearity of the video display, together with variations in brightness and contrast arising from variability in the data, will affect the visual discrimination of features of interest. The loss of displayed information is due to environmental and instrumentation effects, and can be partially corrected for in real-time (i.e. at video frame rates) if the data is digitized and approriately normalized. Methods are described for normalizing the contrast and brightness of video displays and for correcting for luminance compression. Experimental results for a sidescan sonar display demonstrate that statistical normalization and gamma-compensation improve the visibility of seabed features and..