| 摘要 |
<p>In methods of digital image processing, it is a problem to automatically adjust the contrast of an image that contains a bimodal distribution of tone values, such as a back-lit scene, or some close-up flash pictures. The invention solves the problem in a digital image processing method employing a tone reproduction function generated by normalizing a sample of tone values, by statistically testing the sample of tone values for bimodal distribution, and if the sample is determined to be bimodal, testing the statistics of the sample of tone values to determine whether the image contains useful information in the shadows, and if so, adjusting the contrast of the image by increasing the contrast of the shadow portions of the image, and decreasing the contrast of the highlight portions.</p> |
