Principle and Advantages of Machine Vision Measurement

Machine vision systems are capable of measuring the appearance dimensions of products automatically, such as shape contours, aperture, height, area, and other size measurements.

Size measurement is an essential step both in the production process of products and in the quality inspection after production, and machine vision has its unique technical advantages in size measurement.

Principle of Machine Vision Measurement

Industrial vision measurement technology is a type of 3D vision measurement system that features a simple system structure, portability, fast and convenient data collection, easy operation, low measurement costs, and the potential for online, real-time 3D measurement. It is particularly suited for detecting 3D spatial points, dimensions, or large workpiece profiles.

This non-contact measurement method avoids damaging the object being measured and is suitable for situations where the object cannot be touched, such as in high-temperature, high-pressure, fluid, or hazardous environmental conditions. At the same time, the machine vision system can measure multiple dimensions simultaneously, achieving fast measurement completion, making it ideal for online measurement. For measuring small dimensions, machine vision systems excel by using high-magnification lenses to enlarge the object being measured, achieving precision at the micron level.

Machine vision measurement methods can measure product dimensions in one-dimensional, two-dimensional, and three-dimensional formats. Not only are these measurements fast, non-contact, and easy to automate, but they also offer high precision. A measurement approach that combines CCD cameras with microscopes can be used for detailed measurements, such as wafer and chip measurements.

Measurement Principle: By using a CCD camera, it can obtain a two-dimensional image of a three-dimensional object, thus enabling perspective transformation between the actual spatial coordinate system and the camera's plane coordinate system. By capturing two (or more) two-dimensional images from different angles with multiple cameras, the system can comprehensively calculate the 3D surface profile, spatial points, and dimensions of the object.

Currently, the highest precision achievable with machine vision measurement technology has reached sub-micron levels, meeting the precision requirements for most automated production processes. Machine vision systems for measurement and positioning enable faster production line speeds and higher production efficiency.

Advantages of Machine Vision Measurement

Machine vision measurement uses advanced sub-pixel-level object surface scanning methods to meet high-quality point cloud scanning requirements. The system uses high-resolution digital industrial cameras to capture image data. By illuminating the object's surface with stripes, dense point clouds of any complex surface can be obtained in seconds (with point distance depending on the object size, camera resolution, and measurement distance, generally ranging from 0.05–0.5mm). The system's resolution ranges from 1.3 million to 5 million pixels, accommodating different customer needs.
Machine vision measurement uses a true-color object surface reconstruction method. The visual measurement equipment system adopts advanced image texture analysis and acquisition technology, ensuring that while 3D data is reconstructed, the object's surface retains its true color. This technology preserves the object's natural color, maximally restoring its real physical characteristics.
Machine vision measurement employs a fully automated stitching method. Image data from different angles are automatically aligned in a unified coordinate system based on the object's own texture, thereby obtaining complete 3D scanning data. When scanning textured objects, the system does not require placing reference points on the object's surface to complete the stitching, greatly improving stitching efficiency.
The measurement system has minimal dependency on hardware equipment. The optical calibration module of the system uses ultra-high precision semiconductor process products, maximizing calibration accuracy. During data collection, the software performs real-time error correction and strictly corrects multiple lens distortions.