Visual measurement system dynamic correction method based on zero-expansion ceramic calibration plate

Abstract

The invention provides a vision measurement system correction method based on a zero-expansion ceramic calibration plate, which can overcome the influence of high and low temperature change and transmission path airflow density change on measurement accuracy in a test process. A zero-expansion ceramic calibration plate is placed in a measured view field space of the vision measurement system, and a target point is arranged on the zero-expansion ceramic calibration plate; during measurement, each camera in the visual measurement system performs real-time image acquisition, extracts image coordinates of each target point on the zero-expansion ceramic calibration plate, calculates a re-projection error e, and performs parameter correction when e is greater than a preset threshold s; the parameter correction process comprises the following steps: firstly, establishing a relationship between a real value and a predicted value of each target point on the zero-expansion ceramic calibration plate to obtain a distortion correction model; and then, the measurement point space relative coordinates directly calculated under the static parameter calibration condition of the visual measurement system are input into the distortion correction model for calculation, and the output value is the measurement point space three-dimensional coordinates after distortion correction.

Description

technical field [0001] The invention relates to a correction method, in particular to a dynamic correction method for a visual measurement system based on a zero-expansion ceramic calibration plate. Background technique [0002] Stereo vision measurement technology is realized based on the principle of parallax, using multiple cameras with known spatial position and attitude relationship (one of which is the reference camera, and the spatial position and attitude relationship of the other cameras relative to the reference camera is known) to simultaneously collect the measured objects in different orientations. The image of the feature, through image processing and matching of the same name, obtains the same-name image point pair corresponding to the measured feature; then uses the camera imaging model to establish the imaging ray equation, constructs the ray triangle intersection constraint, and builds a multi-eye vision measurement mathematical model, and then solves the pr...

AI Technical Summary

Problems solved by technology

[0007] In view of this, the present invention proposes a dynamic correction method for the visual measurement system based on a zero-expansion ceramic calibration plate, which can dynamically correct the distortion of the visual measurement system applied in special environments such as wind tunnel tests, and can overcome the high and low temperature changes in the test process and the influence of airflow density changes in the transmission path on the measurement accuracy

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