Digital photogrammetry system for non-contact measurement

Photogrammetry system V-STARS (Video Analog Triangulation and Research System) is a three-coordinate measurement system developed by GSI Company of the United States for industrial digital close-range photography. The system mainly has the advantages of high three-dimensional measurement accuracy (relative accuracy can reach1/200,000), high measurement speed, high degree of automation, and can work in harsh environment (such as thermal vacuum). It is the most mature commercial industrial digital photogrammetry product in the world.

The system is a large-scale coordinate measurement system based on digital photography, also known as industrial photogrammetry system, digital close-range photogrammetry system, digital close-range photogrammetry system, digital three-dimensional photogrammetry system and three-dimensional optical image measurement system.

It uses V-STARS software (as shown in Figure 3) to process the collected photos and get the three-dimensional coordinates of the points to be measured. These photos are obtained by shooting the same object in different positions and directions with high-precision professional cameras (such as INCA3 camera of GSI Company of the United States). V-STARS software will automatically process these photos, and get the accurate three-dimensional coordinates of the points to be measured through image matching and related mathematical calculations. Once processed, the three-dimensional data of the measured object will enter the coordinate system, just like it was measured or processed before. If necessary, V-STARS software also has built-in analysis tools, which can output 3D data. Generally, these measured objects are manually affixed with reflective signs in advance, or projected by points through point projectors, or detected by points on sticks. (1) High accuracy: the measurement accuracy of single camera system can reach 0.08mm in the range of 100 m, and that of double camera system can reach 0.17 mm; ;

(2) Non-contact measurement: the measurement method of optical photography, which does not contact the workpiece;

(3) Fast measurement speed: a single camera can complete a large number of point cloud measurements in a few minutes, and dual cameras can measure in real time;

(4) It can measure (temperature, vibration) in unstable environment: the measuring time is short, and it is less affected by temperature, so the dual camera system can measure in unstable environment;

(5) Especially suitable for measurement in narrow space: as long as the space is 0.5m, it can be photographed and measured;

(6) The data rate is high, and a large amount of data can be easily obtained: image points are automatically extracted and measured by computer software, and the speed of measuring 1000 points is almost the same as that of 10 points;

(7) Good adaptability: one system can measure the size of the measured object within the range of 0.5m to 100m;

(8) Good portability: single camera system 1 person can be carried to the site or other places for measurement.