With the development of the field of computer digital inkjet printing, three common basic image conversion algorithms have been formed. On the basis of the conversion principle and their respective advantages and disadvantages are discussed, and on this basis, according to the characteristics of three-dimensional inkjet printing, the proposed three-dimensional image conversion algorithm.

(1) grey component replacement (GCR)

GCR (Gray Component Replacement) in the "gray component" has two meanings. One of the two colors in the CMY color mixed play a leading role in the color of the decision, and the color of the third

The color is called the grey or color components, which play a role as black filled. If you add too much of the third colors, you will darken the image and destroy the hue. For example, red mainly includes magenta and yellow, if added

Too much cyan, red will be impure, in this process is the dominant color red, cyan is a gray component of the original color. Second, the "gray component" refers to a specific color in the approximate amount of green, magenta, yellow color, which

The three primary colors consist of neutral grey, which can be used to replace the color or color of the color. Gray component instead of fat to describe.

(2) background gain (UCA)

GCR is currently in the image conversion method, but in order to keep the color saturation and depth shadow area in the GCR color, the researchers set up color gain method (Under Color Addition). In this algorithm, some black components are removed in the dark color region, and the green, magenta and yellow three colors are introduced in the corresponding region.

(3) background subtraction (UCR)

GCR is to replace the CMY neutral tone within the scope of any black component, and UCR (Under Color Removal) algorithm is to replace the components in the darkened area in black. It is used in the shadow area to reduce the output of the total amount of ink coverage, while adding details, suitable for the image of the shaded part of the color image. The disadvantage is darkened monotonous and lack of contrast. Thus the neutral grey image darkened mainly to get the best effect.