Method and apparatus for measuring three-dimensional curved surface based on instantaneous accidental light irradiation

Abstract

The invention provides a three-dimensional curved surface measuring device and a method based on instant random illumination. The device comprises two digital cameras, a control circuit board, an instant random light field projection device, a computer and a calibration board. The computer controls the two cameras through the control circuit board to synchronically take a three-dimensional image pair without auxiliary light projection, then a projecting apparatus is immediately started to project a purely random image onto the surface of an object to be measured, and the two cameras synchronically re-take another three-dimensional image pair of the object to be measured under the irradiation of a random light field; the first three-dimensional image pair is used for synthesizing multi-angle measurement and generating textures of a three-dimensional model; according to the three-dimensional image pair of the measured object under the irradiation of the random light field (the second three-dimensional image pair), a weighted least square method is adopted with the constraints of geometry and grayscale to build sub-pixel correspondence among image points, and at the same time, a dense three-dimensional point cloud is acquired. The method is characterized by short measurement duration, simple structure, easy realization, and suitability for on-site measurement.

Description

technical field [0001] The invention belongs to the field of three-dimensional sensing and measurement, in particular to a three-dimensional curved surface measurement device and method based on instantaneous random illumination. Background technique [0002] Three-dimensional surface measurement technology is one of the research hotspots in the field of three-dimensional sensing and measurement at home and abroad. It is widely used in various fields such as aerospace, automobile and ship, machinery manufacturing, and biomedicine. At present, the mainstream non-contact measurement methods mainly include the following: ①Laser single-point measurement method, because this method can only measure one point at a time, although the measurement accuracy is high, but the efficiency is extremely low; ②Laser line scanning method, this method It is single-line scanning, which has higher efficiency and higher measurement accuracy than single-point measurement. It is a relatively mature...

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Problems solved by technology

At present, the mainstream non-contact measurement methods mainly include the following: ①Laser single-point measurement method, because this method can only measure one point at a time, although the measurement accuracy is high, but the efficiency is extremely low; ②Laser line scanning method, this method It is single-line scanning, which has higher efficiency and higher measurement accuracy than single-point measurement. It is a relatively mature method, but the measurement of the surface of the object to be measured by this method must be realized by precise motion control of the laser line;③ Moiré fringe method, this method is to superimpose the deformed grating image with the reference grating with the same period, and use the obtained pattern to draw the contour line of the measured object. It belongs to the whole field measurement and can measure dynamic objects, but the measurement accuracy is not high. , the device is more complicated; ④ structured light coded projection method, which projects structured light containing coded information to the measured object, and realizes point cloud measurement of three-dimensional object surface by analyzing the image of the measured object illuminated by structured light, the most common one is grating projection , this method can achieve high precision and data density, and is relatively mature, but because it needs to project grating stripes multiple times and take multiple images in time series, the measurement duration is relatively long, during which the measured object Both the measurement equipment and the measurement equipment need to be kept absolutely still, so this method is sensitive to the environmental vibration and the structural stability of the measurement equipment, which limits its application in some special occasions.

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