A Bridge Type CNC Vision Measuring System is an advanced piece of metrological equipment used primarily for precise dimensional and geometrical measurements of manufactured components. This type of system typically features a bridge structure that supports a high-resolution camera system and lighting, moving over a stationary object table.

Video Measuring Machine (VMM), also known as a vision measuring system, operates based on the principles of optical non-contact measurement technology. It combines high-resolution video imaging, precise optical and lighting systems, and advanced software to measure the dimensions of objects with great accuracy and speed. Here's a detailed look at the working principle of a Video Measuring Machine:
1. Image Capture: At the core of a VMM is a high-resolution digital camera, which captures images of the object placed on the machine's stage. The object is illuminated by a combination of bright-field and dark-field lighting to enhance various features and edges for better visibility and measurement accuracy.
2.  Optical System: The camera is often equipped with a zoom lens system that can be adjusted to view the object at different magnifications. This allows for flexibility in measuring objects of various sizes and details.
3.  Stage Movement: The object is placed on a flat, stable stage that can move in X, Y, and sometimes Z axes. This movement is typically controlled by computer-driven motors that position the object precisely under the camera. In some machines, the camera and optics move instead, while the object remains stationary.
4.  Software Processing: The captured images are processed using specialized software. This software applies various algorithms to recognize edges, shapes, and features of the object. It calculates dimensions such as distances, angles, radii, and other geometric parameters by comparing the known scale of the image with the pixel dimensions in the captured image.
5.  Edge Detection: One of the key functions of the software is edge detection. It identifies the exact points on the object where edges occur, which is critical for dimensional measurement. The software determines these points based on changes in contrast or color detected by the camera.
6.  Calibration: To ensure accuracy, the VMM is calibrated using standards or known references. Calibration compensates for any optical distortions or inaccuracies in the machine's mechanics or imaging system.
7.  Data Output: Finally, the measurements are displayed to the user and can be exported to other systems or used to generate detailed reports. The software may also provide statistical analysis to monitor quality control processes.