Lecturer in Sarjanawiyata Tamansiswa University, I Nyoman Jelun Erosa, explained that Acquisition System of Stereo Images (SACiS) is a terrestrial based method to measure distance and elevation of static and dynamic objects. SACiS consists of a number of imaging objects (ball or disc), imaage scale, a pair of stereo cameras, camera synchronisers, computer, and sofware to reconstruct stereo image into 3D image. "For application of terrain map or topography, image scale can be integrated with a reference coordinate on the ground,” he said at KPTU building of Faculty of Engineering, Universitas Gadjah Mada on Friday (27/1), when sitting for an open examination for his doctoral program in Electrical Engineering UGM.
The principle of SACiS is that some image objects are located on the surface of object that will be measured. The image of the objects is acquired using a stereo camera.The stereo image is then reconstructed into 3D image. As such, the reconstructioninto 3D image is a process to measure the distance and elevation (coordinate) of relative image objects toward the position of the camera, the coordinate of relative image projects toward the position of the camera, so the coordinates of image objects can be extracted from the 3D image. “If the object measured is dynamic, the acquisition stereo image is with a video camera or camcorder so changes in coordinates of image objects are resulted in intervals of image acquisition or during measurement,” he stated.
Results showed that tests related to optimalisation of stereo image acquisition techniques and optimalisation of management technique of 3D image, an optimum SACiS performance can be gained. In optimum performance condition, SACiS is used to measure the distance of some relative static objects toward a reference point on the ground and sea wave model. “One by one the result is verified to the measurement using theodolite and probe,” he added.
Defending his dissertation entitled Development of Acquisition System of Stereo Images (SACiS) to Measure Distance and Elevation of Static and Dynamic Objects, Nyoman Jelun described that SACiS proved that it can be used to measure the multi-coordinates of relative static and dynamic objects toward the position of camera simultaneously.
SACiS can also be used to measure sea waves, trajectory and velocity of surface flow of sea wave, river stream, and other objects related to static and dynamic objects. “In terms of accuracy, SACiS is very dependent on the image object, contrast of object colour with background colour, video camera type, length of camera focus, stereo image similarities, target marking technique and calibration techniques,” he explained.