说明：  matlab 图形图像处理。通过GUI，用户可以自由的变换RGB颜色等等。
(The color of each pixel in an image is specified by a combination of three values: red, green, and blue. These values typically take 256 levels, leading to 256^3 ~ 17 million possible colors. In this GUI you can set a threshold value for each channel (R/G/B). If the color is above the threshold, it takes the maximum value (255) if not, it takes the minimum value (0). This "all or nothing" approach means that each color channel has only two possible levels, resulting in only 2^3 = 8 colors. Hence, each of the 17 million possible colors is "rounded" to one of: red, green, blue, cyan, yellow, magenta, black, and white. The result is an effect reminiscent of Andy Warhol s iconic celebrity paintings. )