Machine vision system has measurement function, which can automatically measure the appearance size of products, such as outline, aperture, height, area and other dimensions.
Dimension measurement is an indispensable step both in the production process and in the quality inspection after the product is produced. Machine vision has its unique technical advantages in dimension measurement.
Measurement Principle of Machine Vision
Industrial vision measurement technology (or digital near-field photogrammetry) is a kind of stereo vision measurement technology. Its measurement system is simple in structure, easy to move, fast and convenient in data acquisition, easy to operate, low in measurement cost, and has the potential of on-line and real-time three-dimensional measurement, especially suitable for three-dimensional space points. Detection of dimension or contour of large workpiece.
This non-contact measurement method can not only avoid the damage to the tested object, but also suit the non-contact situation of the tested object, such as high temperature, high pressure, fluid, environmental hazards, etc. Meanwhile, machine vision system can simultaneously measure multiple sizes together to achieve the rapid completion of the measurement work, which is suitable for on-line measurement. The measurement of small size is also the advantage of machine vision system. It can magnify the measured object with high magnification lens, so that the measurement accuracy can reach more than micron.
For product size measurement, including one-dimensional, two-dimensional and three-dimensional measurement, machine vision measurement method is not only fast, non-contact, easy to automate, but also high precision. Among them, the CCD camera combined with the microscope can be used for fine size measurement, such as wafer measurement, chip measurement and so on.
Measuring Principle: Two-dimensional image of three-dimensional object can be obtained by using CCD camera, which can realize perspective transformation between actual space coordinate system and camera plane coordinate system. Through two or more frames of two or more images taken by multiple cameras from different directions, the three-dimensional surface contour or the three-dimensional space point position and size of the object can be measured synthetically.
At present, the highest accuracy achieved by machine vision measurement technology has reached the sub-micron level, and can meet the accuracy requirements of most automated production at this stage. Measuring and positioning through machine vision system can make the production line faster and more efficient.
AI Intelligent One-button Measuring Instrument
Advantages of Machine Vision Measurement
1. Machine vision measurement uses advanced sub-pixel surface scanning method to meet the needs of high-quality point cloud scanning. The system uses a high resolution digital industrial camera to collect image data. Through the fringes of the light source on the surface of the object, the dense point clouds on any complex surface can be obtained in a few seconds (the specific density depends on the size of the object being measured, the resolution of the camera and the measuring distance, in general, the point distance is 0.05-0.5mm). The resolution adopted by the system is 0.05-0.5mm. From 1.3 million to 5 million pixels, it can meet the needs of different customers.
2. Machine vision measurement of true color object surface reconstruction method, visual measurement equipment system uses advanced image texture analysis and acquisition technology, while reconstructing three-dimensional data to maintain the true color display of the object surface. This technology retains the true color of the object to be measured and restores the true features of the object to the greatest extent.
3. Automatic mosaic method for machine vision measurement. Image data from different perspectives are automatically combined in a unified coordinate system based on the texture of the object itself, so that the overall scanning data of the three-dimensional image can be obtained. When scanning texture-rich objects, the system can complete the stitching function without pasting any reference points on the surface of the object, which greatly improves the stitching efficiency.
4. The accuracy of the measurement system is the lowest dependence on hardware. The optical calibration module of the whole system adopts ultra-high precision semiconductor technology products, which maximizes the calibration accuracy. In the process of acquisition, the software corrects errors in real time, and corrects many kinds of lens distortion strictly.
5. Machine vision measurement system is simple to set up and easy to use. In the overall development process of the three-dimensional scanner, the concept of "software can handle, never let users handle" is adhered to, so as to minimize the number of user settings parameters of the whole system. The running period of the scanning software will dynamically calculate the required parameters in a more precise way, which not only avoids the unnecessary settings that the user participates in manually, but also makes the whole system more adaptable, more automated and less likely to make human errors.
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