| 摘要 |
Image-dependent tone and color reproduction processing of digital images is accomplished by creating a spatially blurred and sub-sampled version of the original image, and applying knowledge of the capture device physical characteristics to obtain statistics related to the scene or original captured. The statistics are used for image-dependent linearization of the captured image data based on an OECF model, and in conjunction with information about the output medium, to calculate image-specific preferred tone reproduction curves based on a preferred reproduction model. These curves may be applied to the red, green, and blue channels of RGB-type images to produce preferred tone and color reproduction, or to the luminance channel of luminance-chrominance type images to produce preferred tone reproduction. Alternately, the linearized image data may be reproduced directly. Also, if the original is assumed to already possess preferred reproduction, the preferred reproduction model may be used to undo the preferred reproduction on the original. The image data can then be processed for reproduction on output media with different density ranges and color gamuts. All the processing described can be accomplished automatically, but the access to accurate scene information afforded by the image-dependent linearization, and to the perceptually intuitive parameters controlling the calculation of the preferred reproduction curves, also allows for simple, intuitive manual adjustment.
|
