Tiefu Ding

Self-Adaptive Threshold Canny Operator in Color Image Edge Detection

It needs to set the two thresholds of classical Canny Operator manually, which confined this algorithm. A lot of research on adaptive thresholds choice method has been done to conquer this shortcoming. Based on the gradient histogram, which is studied constantly in the past, a method of gradient histogram difference diagram with adaptive image classification techniques is proposed in this paper. It automatically sets the two thresholds, and avoids disconnected or false edges in detection. Experiments prove that the method is threshold-adaptive and the edge detection performs well in color image whose larger gradient amplitude pixels are mainly located in the edges between the target and background.

The Deviation of Color Matching Algorithm in the Field of Full-Color LED Display

In this paper, a color gamut transformation method which transformed the different color gamut into a same one has been proposed. In the transforming process, the deviation which was arose from the quantization error and the truncation error were existing. If the deviation was out of the color tolerance, the uniformity of the screen color will be deteriorated. Firstly, the color tolerance of vision was calculated by the color-difference formula. Secondly, in the full-color LED display experiments, it was analyzed that the tri -color tolerance values are respectively 2.5, 2.8 and 1.3. According to the tri -color tolerance values and the color difference formula, the express of the quantization precision, gray value and the color difference was set up. Finally the gray-scale range of the color uniformity was analyzed by the collected data, it was concluded that the uniformity of the display was satisfied the requirement of the visual when the range of the gray level was (11, 14), and when the range was (1, 11), the value of the color difference was also reduced significantly.