614 results about "Dark zone" patented technology

Disclosed is a method for generating transfer curves for adaptive contrast enhancement. Transfer curves are generated so as to enhance the bright pixels in mostly dark images and the dark pixels in mostly bright images. For a dark image, a transfer curve is generated which increases luminance in high-luminance regions of the image without substantially changing the luminance in the mid- and low-luminance regions of the image. For a bright image, a transfer curve is generated which decreases the luminance in the dark areas of the image without substantially changing the luminance in the mid- and high-luminance regions of the image. For a medium-bright image, a transfer curve is generated with increases the luminance in the high-luminance range and decreases the luminance in the low-luminance range of the histogram without substantially changing the luminance in the medium-luminance range of the image.

The invention provides a human visual perception simulation-based self-adaptive low-illumination image enhancement method. The method is put forwards based on characteristics of low brightness and low contrast of a low-illumination color image and through researching an automatic adjustment process of pupils and photoreceptor cells for an environment. The method includes the following steps that: the adjustment process of the pupils for light is simulated, and the total brightness level of the image is improved; and the self-adaptive adjustment and control ability of eye vision for a low-illumination environment is simulated, and a nonlinear mapping model is designed to simulate the adjustment process of rod cells and cone cells, so that a bright and dark self-adaptation function can be obtained, and a bright and dark information fusing function is determined according to illumination distribution, and global self-adaptive adjustment is performed on brightness components; and the local contrast of the enhanced brightness image will be decreased, so that local self-adaptive contrast enforcement is performed on the image through adopting an exponential function; and finally, and color restoration is performed on the enhanced image. With the human visual perception simulation-based self-adaptive low-illumination image enhancement method of the invention adopted, the brightness, local contrast and detail information of the low-illumination color image can be effectively improved, and especially, the method has obvious effects in dark area and highlight area enhancement.