By Construction Tech Review | Tuesday, May 14, 2019
The rapid development of automatic image analysis has opened new doors for users having no specific knowledge about photogrammetry. The digital transformation has boosted the evolution of 3D measurement technologies ranging from low-cost sensors to expensive and sophisticated systems. Traditional photogrammetric approaches are being integrated with methods like visual odometry, structure from motion (SfM), and simultaneous localization and mappings (SLAM) to enhance the control and sensor systems of autonomous vehicles (AVs) and unmanned aerial vehicles (UAV).
Close-range photogrammetry offers sophisticated sensor technology to UAVs and AVs, including industrial cameras, metric cameras for specific photogrammetric applications, cameras for professional applications, high-speed cameras, multi-camera systems, panoramic cameras, action cameras, and fisheye cameras.
The latest imaging sensors utilize complementary metal-oxide-semiconductor (CMOS) technology. These sensors are mostly used for advanced applications like high-speed imaging. In hybrid sensor systems, the camera sensors are integrated with measuring devices. Terrestrial laser scanners are equipped with specialized cameras for capturing panorama images and recording color values of the laser scan. Some scanners come with thermal cameras with the capability of measuring temperatures.
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In the case of 3D object reconstruction, the outer orientations of the image need to be measured. The system utilizes space resections and intersection and relative and absolute directions to calculate the approximate values. The bundle adjustment minimizes the residuals of the observations and determines the desired calibration and coordinates of the tie points. The statistical quality parameters are carefully examined to generate a picture of internal precision of adjustment.
UAV photogrammetry has become a standard measurement technology with the development of AVs and drones. It is an essential tool for tasks such as road mapping, construction site observation, archaeological surveys, environmental mapping, and others. For optimum results, UAV photogrammetry requires not only extensive skills but also a high-quality lens system, camera stabilization, enhanced intersection angles, as well as an ideal distribution of control points.
The evolution of photogrammetry is transforming the traditional measurement technologies, giving rise to new possibilities. The sophisticated imaging technologies call for advanced skill sets to maintain optimum quality in photogrammetry. Hence, there is a need for meticulous training to develop the mastery of evolving photogrammetry techniques.