Development of a composing method using color information for multiple three dimensional data

Three-dimensional (3-D) model can be constructed by composing multiple 3-D data obtained by non-contact 3-D measurement equipment Recent equipment can obtain not only 3-D position data but also red, green and blue color brightness data. This paper describes an automatic method that utilizes the color information for composing the multiple 3-D data. United distance that is sum of 3-D distance and color distance multiplied by weighted coefficients is defined. Also the mean for calculating the closest point that minimizes the united length using triangular area co-ordinate is devised. The method obtains conversion matrix that minimizes average united distance (3) among closest points of two 3-D data by improving the matrix and closest points repeatedly. Also two-step process is applied; first best conversion matrix is derived from the extracted data points; and next all data are moved and the matrix is improved. The results of the experiment show that when the coefficient 0.9 is used for 3-D distance and 0.1 for color distance, two data can be composed in the position where not only shape but also color of the surface is matched. Also processing time can be reduced one sixth of whole data process by extracting from one thirty-second to one sixteenth data points.