Patent Document ID: 20060152764
Application ID: 11034057
Patent Status: 0

Claim One:
1. A method for controlling a tone reproduction curve of a halftone digital image, the method comprising: receiving the halftone digital image; selecting a target pixel and a neighborhood area of the selected target pixel; estimating a local gray value of the selected target pixel and the selected neighborhood area; determining a modification value for the selected target pixel based a relationship between the estimated local gray value and a desired gray level; modifying a pixel value of the selected target pixel using the determined modification value; determining a quantization error for the selected target pixel, wherein if the determined quantization error is a not equal to zero, the method further comprising: selecting a diffusion mask, the mask relating to the target pixel and pixels neighboring thereto; and diffusing the determined quantization error to at least one pixel based on the selected diffusion mask.