A method of characterizing and enhancing the pixels in an image, which is
captured at all lighting conditions. The method enable dynamically
enhancement of images captured at extremely low lighting conditions. Each
pixel of the image, represented by I SUB (x, y) where x is the horizontal
axis coordinate value and y is the vertical axis coordinate value,
contains three color-components. Each pixel is characterized by defining
a relationship between the three color-components of that pixel in its
initial state. A nonlinear expansion function, which adaptively adjusts
the expansion rate with respect to the statistical property of the
original image, is used for enhancing the brightness of the image so that
the poorly lighted pixels are enhanced in intensity more as compared to
the amount of enhancement for the brighter pixels. The color property of
each pixel in the enhanced image is then restored using the
characteristic features previously defined by the relationship of the
color components. This procedure provides an enhanced image, which is
natural in its appearance and has sharp visibility to human observation.
In addition, this new technique is fast enough to provide a real time
enhancement of images from a video stream.