The entire system of 3D structured light includes structured light projection equipment, cameras, image acquisition and processing systems. The process is that the projection equipment emits light onto the object to be measured, the camera captures the three-dimensional light pattern formed on the object to be measured, and the captured image is processed by the acquisition and processing system to obtain the surface data of the object to be measured. In this system, when the relative position of the camera and the projection device is fixed, the degree of change of the light projected on the measured object depends on the depth of the object surface, so a light image with depth can be obtained in the captured image.
The 3D structured light mode includes point, line, and surface modes, which refer to the type of light projected. For example, here the phase difference between point A and point C is needed to calculate the height. How are these two points reflected in the fringe image captured by the camera?
This is the fringe image before and after modulation. The red points in the picture are equivalent to points A and C in the above picture. The pixel coordinates of the two points are the same, but the phases are different. The phase difference under the same coordinates is obtained. The height of point D that can be obtained indirectly. That is to say, the speckle or stripe structured light patterns at any two places in space are different. As long as such structured light is applied in the space, the entire space is marked. Put an object into this space, and you can know where the object is by looking at the speckle pattern on the object. Of course, the speckle pattern of the entire space should be recorded before this, so the light source calibration should be done first, and the distance between the current object and the camera can be accurately calculated by comparing the light spot distribution on the calibration plane.
