|| STUDY OF IMAGE MEASURING TECHNOLOGY BASED ON INFORMATION FUSION|
|| image measurement, information fusion, edge detection, subpixel edge location|
Image measuring technology based on computer vision theory has such advantages as non-contact, full viewing field and low cost. And information fusion technology could coordinate several sensors’ information from different time, space or type to get characteristics of a unified expression. This paper makes use of information fusion technology in image measuring technology, and constructs mathematical model of multi-source image measuring system. Measuring principal is analyzed and core measuring scheme is designed in detail.
For diameter parameter measuring problem of single-crystal silicon during its manufacturing procedure, image filtering algorithm and edge detection algorithm are respectively simulated and experimented. More proper processing algorithm is chosen according to experimenting results and specific applying object. Then several objects are measured utilizing trimmed mean-based weighed fusion algorithm in information fusion technology. Experiments results show fusion estimation value is closest to real value when trimmed ratio ranges between 0.2 and 0.3.
Subpixel location technology is developed from classical edge location algorithm, achieving effectively improving measuring accuracy at low cost relatively. Existing subpixel edge detection operators are introduced in this paper, and then an improved Orthogonal Fourier-Mellin Moment subpixel edge location algorithm is presented. This algorithm firstly makes use Canny operator to extract all possible edge points at pixel level and then utilizes subpixel-level edge detection operator, Orthogonal Fourier-Mellin Moment operator to location subpixel level edge location. Experiment results show that this algorithm could achieve equal location accuracy compared with Zernike and OFMM subpixel edge location operator but consume less operating time. It can be concluded that such location algorithm is efficient.
Illumination design is an essential issue in vision measuring technology. Several measuring-influencing factors of non-coherent lighting illumination are discussed in the paper, consisting of illumination mode, illumination level, lighting quality and surface characteristic of object to be measured. Then measuring system is constructed to test different characteristics of different lighting mode, and measuring results of different illumination level and image histogram are analyzed to get system lighting illumination scheme. System error sources are analyzed at last.