Associated reference telecentric measurement quick calibration method under super-field-of-view scale

Abstract

The invention provides an associated reference telecentric measurement quick calibration method under a super view field scale, and the calibration method achieves the associated reference telecentric measurement calibration under the view field scale based on a telecentric vision system through an in-situ calibration method and a dimension chain correlation method from a measurement region to a measurement reference axis. The telecentric vision system comprises a workbench, a precise pose adjusting mechanism, a measuring camera, a to-be-measured workpiece, a background light source, a triggering photoelectric sensing mechanism, a transmission target and a three-dimensional correlation target. According to the invention, image feature extraction and accurate position measurement of local to-be-measured elements of a long-scale workpiece are realized, then a measurement transfer chain of the local to-be-measured elements and axis reference elements outside a camera imaging field of view is established, and the local elements are converted into global radial dimensions through calculation. Therefore, quick and precise measurement beyond the imaging view field scale is realized.

Description

technical field [0001] The invention belongs to the technical field of rapid and high-precision online visual calibration measurement in industrial inspection of production lines, and in particular relates to a rapid calibration method for associated reference telecentric measurement under the super-field scale. Background technique [0002] In industrial inspection applications, there is a class of parts whose topological structure is as follows: figure 1 As shown, this kind of parts has the actual demand of on-line measurement. The distance between the edge elements of the protruding tip of the cross section and the axis of the long rod is the key geometric quantity for measurement, which is related to the rotation accuracy after assembly, but its own structural characteristics are not It brings some difficulty to online measurement. This type of parts is similar to the precision shaft system, with the technical characteristics of long rods and rotary technology; the part...

AI Technical Summary

Problems solved by technology

[0003] Due to the special structure of this type of workpiece, the application of existing non-contact measurement methods and equipment is limited, such as grating projection measurement, which is sensitive to reflective materials on metal surfaces, and the elements to be measured are sharp corner points, and the precise extraction of elements is limited; When using three-coordinate measuring machine laser triangulation for measurement, it also faces the above-mentioned similar problems. It is difficult to accurately obtain the corner point elements of the tip; the more common image measurement method has the ability to measure when the parts on the shaft are at the end faces of both sides of the long rod. However, when the part on the shaft is located in the middle shaft diameter, how to realize the distance from the edge tip element to the axis has become a difficult problem. At present, most of the methods used are artificial image decomposition measurement, but the efficiency is low, and the assembly accuracy cannot be objectively evaluated.

In addition, due to the radial scale extension of the parts on the shaft, high-precision optical measurement systems generally cannot image the shaft end face and the tip of the part at the same time under a large optical aperture, because the large optical aperture will affect the measurement accuracy. The optical aperture covers a larger mechanical aperture, which means that the cost increases and the system design is more expensive

Images