Study On Three-Dimension Measurement Based On Digital Image Transformation

The research purpose of computer vision is to make computer perceive surroundings information. The image-based measurement technique is one kind of novel noncontact measurement technique, which develops from the computer vision realm and primarily regards images as the carrier and means to detect or transfer the information. The image-based measurement technique can bring us the depth information of the examined object after dealing with the characters detected from the images. Moreover, this measurement technique has very strong adaptability in the aspects of accuracy, speed, intelligence and so on.Use the digital camera to take the drier's cab images, analyze and compare the common digital image transformation technique, find the digital image transformation which are fit for textual, then can easily to take the point coordinate from the edge image.Compare the calibration precision of simple Direct Linear Transformation in the case of different quantity and distributing figure reference point, choose good reference point of calibration precision distributing figure. Adopt DLT calibration to work out eleven linearity calibration parameters. Take eleven linearity parameters as initial value, and resolving nonlinearity model camera calibration parameter which contain distorted lens parameter (k₁, k₂, k₃) with the iteration method. Using some extra not participation DLT reference point's residual to participation error fitting, and then improves calibration precision. Make these measured value error of the additional reference point to achieve the minimum value with the optimization algorithm, reduces survey error of object three dimensional.According to the basic principle of stereoscopic vision, with parts of parameters in the car drive for test object, carry on a three dimension reconstruction, get the three dimension information of the object and the opposite position of the object. The experiment verified a method which based on digital image transformation of three dimension measurement possibility. This text optimized the calibration method and raising survey precision.