Grating stripe image projection sequence fast switching system and method

Abstract

The invention discloses a grating stripe image projection sequence fast switching system, which comprises an upper computer, a 3D scanner and an FPGA. The FPGA comprises a first storage region and a second storage region. The second storage region is divided into a plurality of storage sub-regions Ci, i=1,2, 3...m, m being the number of different vehicle models to be tested. The first storage region is used for providing a memory required for program running; and the plurality of storage sub-regions Ci are used for storing grating fringe image projection sequences required for measurement of different vehicle models, wherein each grating fringe image in each grating fringe image projection sequence has a corresponding image number. Grating images for projection can be directly taken from adynamic memory through FPGA logic control, and delay in switching from a sequence to a projection process is less than 1ms; the system is especially suitable for projection of high-resolution gratingimages; and in the whole vehicle body measurement process, the system can load the projection sequences of the different vehicle models to the storage sub-regions while carrying out projection measurement, thereby reducing early-stage preparation time in measurement of other vehicle models.

Description

technical field [0001] The invention relates to the field of three-dimensional scanning measurement, in particular to a system and method for switching grating fringe image projection sequences. Background technique [0002] The three-dimensional scanning measurement method uses a three-dimensional scanner to project multiple raster image projection sequences onto the surface of the object to be measured in sequence, and the camera obtains the deformed grating image. It is a non-contact optical measurement system that realizes the point cloud through grating projection. Acquisition, equipped with moving mechanisms such as robots, guide rails, and turntables to achieve large-scale flexible measurement, high-density point cloud measurement, and truly restore the rich surface details of objects. [0003] The higher the resolution of the 3D scanner, the more information contained in the raster projection image, and the more abundant point cloud data obtained. Projecting a high-r...

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Problems solved by technology

[0003] The higher the resolution of the 3D scanner, the more information contained in the raster projection image, and the more abundant point cloud data obtained. Projecting a high-resolution projection image can bring about an exponential increase in image information and improve the overall 3D scanning. The measurement accuracy of the measurement system, but with the improvement of the projection image resolution, it will directly affect the projection rate and switching time of the projection sequence. The usual practice is to first store the raster image projection sequence in the memory device Flash outside the scanner. The control chip reads the required raster image projection sequence from Flash to DRAM (Dynamic Random AccessMemory). In this way, when the projected image is high-resolution, a main control chip needs to be added to meet the requirements. For example, TI's DLPC900 is used. As the main control chip, when the projection resolution is increased from 1920x1080, there are more than 2 million digital micromirrors on the corresponding DMD chip (Digital Micromirror Device, that is, a data micromirror device) to 2560x1600, and there are 4 million digital micromirrors on the corresponding DMD chip Micromirror, the data volume of the projected image has doubled, which is equivalent to the original need to drive a 2 million-level digital micromirror, but now it needs to drive two 2 million-level digital micromirrors. At this time, two main control chips are required DLPC900, the cost increases; at the same time, in the traditional sequence switching and storage method, because the DRAM space is not large enough, when the measured object changes, such as the automobile body-in-white measurement process, when the measured model changes and the raster image projection sequence needs to be changed, the 3D scanner The projection main control chip needs to take pictures from the flash again, and then input them into DRAM. The whole process takes a long time. Taking the TI control chip to realize the switching of 20 projection pictures of 1920x1080x8bit as an example, each time a new sequence is switched, the DLPC900 needs to re Read the image sequence from Flash, and recombine the original 8bit projection image into a 1bit bitmap and store it in the internal cache of the chip. The whole process takes more than 1s

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