A detailed description of the angle measurement technology of the image measuring instrument

A detailed description of the angle measurement technology of the image measuring instrument. Improving the angle measurement accuracy of automatic imagers has always been a problem. There are two main methods for automatic imager angle measurement: tangent method and sampling point calculation method. The tangent method only requires the operator to rotate the inner line of the lens or the screen, align the two edges of the measuring workpiece, and then use the encoder or circular grating to count to measure the angle. The tangent method is easy to operate, but the reading density is low, which is suitable for rapid batch inspection . If the DUT is required to have a higher angular density reading, it is more suitable to use another method, that is, the sampling point calculation method. All geometric elements have a certain combination, including the basic elements of straight lines, curves and arcs. The two-dimensional plane angle is composed of two basic geometric element straight lines, and the straight line is composed of countless points, so no matter whether the angle measurement is accurate or not, the mining point is more critical.

Automatic imager: The angle measurement technique used for linear acquisition is as long as possible. Due to the limited screen display, the magnification is usually 0.7-4.5-34x-220x, and the size of the workpiece displayed on the screen is only a few millimeters. Many surveyors only use the points and lines collected on the screen during the test. If there is a deviation in the collection point, the shorter the straight line segment, the greater the deviation of the angle measurement value, the longer the straight line segment, the smaller the deviation of the angle measurement value, so when we measure the angle, we try to collect the lines on both sides of the angle, If the screen display range is too small, we can move the table, select a point at the starting point of the straight line where the angle is located, and then select a point at the end point, which can greatly reduce the error. Image measuring instrument angle measurement technology: the deviation of the regression line is very small. Many inspectors replied that the repeatability when measuring angles is very poor. In the same method of the same person, the repeat error of the two measurements is as high as 0.5 degrees. Many image measurement software, including three-coordinate measurement software, default to two points for straight line collection. For some conventional parts with good linearity, it will not cause too much However, for parts with poor linearity and more burrs, the two-point linear collection method will bring greater errors and poor repeatability. Such a linear angle is definitely not suitable for repeated measurement.