Development of Automatic Identification for Color Coded Targets

Abstract

The 3 Dimensional Measuring System is a device to obtain the 3 dimensional coordinates of an object, using its numerous photo-images taken from different angles. This method basically requires the exact identification of the same corresponding points of all the obtained photo-images. But the more numerous are the images, the longer and harder it becomes if we depend on the manual work. To solve this problem we have developed colour-coded targets and a special algorithm with software, which automatically identifies the corresponding targets. The color code target that we developed has several features. The kinds of the color used for the code is six. On each target the same color should be used only in one place. Thus we could obtain 720 different combinations for the codes. However, in every actual situation, the condition of light, photo-taking and printing varies or is different and this create color-shift. To solve this problem, we added the sections to the target as a standard color reference or criterion parts. Thus by comparing the color in code-color section with these reference parts the correct identification of the color is always guaranteed and the color shift can be completely ignored. We made careful experiments and verified its efficiency with the very satisfactory result.