Nowadays, with the increasingly extensive application of machine vision technology, the demand for machine vision in scientific research and teaching has also become higher and higher. High precision system calibration is the premise and foundation of precision measurement and detection of machine vision system. The application of calibration plate can improve the accuracy of measurement system and solve the problem of machine vision calibration. So why do we use calibration plates in machine vision? Here's a brief introduction:
The use of calibration plates in machine vision mainly includes the following two aspects:
1. Error measurement and evaluation
The high-precision calibration system realizes this process by combining the images collected by the precisely portrayed professional image calibration board in the machine vision system environment with the professional calibration algorithm. The system can accurately obtain the error values at any position within the field of vision, and evaluate the accuracy level of the machine vision system based on the error data.
2. Correction and compensation of error image
The calibration system corrects and compensates the position of each pixel information on the image according to the error data obtained in the first step. This process involves a variety of precision image algorithms such as image translation, rotation, interpolation, reconstruction, and brightness compensation. The image corrected and compensated by using the calibration plate can more accurately reflect the actual situation of the tested object, and achieve the purpose of precision measurement and detection.
Any machine vision system involving position and size accuracy must be calibrated, but the calibration method can be appropriately selected according to different application fields. Generally, the accuracy of the calibration system should be in the same order of magnitude as the accuracy requirements of the measurement system, and the calibration error of the calibration plate should not be greater than one measurement unit. For example, if the accuracy of the measurement system is required to be ± 50 microns, the accuracy of the calibration system must be 10 microns, The calibration system error shall not be greater than 10 μ m.
To sum up, there are two main aspects of using calibration plates in machine vision. In the application of machine vision, the use of calibration plate is very necessary, because for accuracy measurement, the distortion of the lens itself is inevitable, and at the same time, it needs to achieve the accuracy that customers are satisfied with, so the image itself is required to be very real and accurate, otherwise, no matter how high the software level is, it is also based on the image with errors, and the subsequent results must have large errors. However, high-precision system calibration is the premise and foundation of machine vision system for precision measurement and detection. It can improve the accuracy of the entire measurement system through two steps.
