The Basic principles and applications of image RTK measurement
Image measurement usually uses cameras and other shooting equipment to take pictures at two or more different known locations, or by arranging object image control points and taking pictures at any location to form a stereo image pair, and then post-processing the photos to obtain the three-dimensional coordinates of each observation point. Integrating RTK positioning technology with close-range photogrammetry technology, and combining the advantages of real-time RTK, high accuracy, high efficiency of close-range photogrammetry, and rich measurement results, can effectively solve the problem of RTK without fixed measuring stations or control points. In the urban measurement environment, the problem of poor signal and photogrammetry relies on control points, and has higher operating efficiency for traditional point measurement (photos or images as information carriers contain the largest information of the measured target, surface measurement), and more Rich measurement results (various data, graphics, images, digital surface models and three-dimensional dynamic sequence images).
Common usage scenarios of image RTK include:
● Suitable for urban measurement environments where satellite signals are blocked or RTK fixation effects are poor in building blind spots.
● Non-contact measurement, suitable for dangerous and enclosed areas.
● Building facade measurement, earthwork measurement, etc.
● It can supplement ground image data and match UAV air-ground integrated modeling.
The entrance to the image measurement function of Hi-Survey software is as shown in the figure. After entering the image measurement, you can see the camera interface. Use the camera on the side of the GNSS to aim at the object to be measured and adjust the angle by yourself. It is recommended to take at least 6 photos with a certain degree of overlap at a certain arc shooting position for software calculation. After the solution is completed, use the software cursor to hit the same feature point on at least two photos to obtain the three-dimensional coordinates of the measuring point.
The high-performance image processing technology of the Image Disk is adapted to the Android platform, and the calculation speed is extremely fast. It can complete the calculation of 6 photos in about 20 seconds. The coordinates of all points in the picture can be obtained directly on site in real time. The typical measurement accuracy is 2-4cm.
Post time: Nov-09-2023