The High-precision Measurement Technology Of Distance Of Small Area Light Screen

The double-slit light screen velocity measuring system calibration of 20mm small target distance measurement with high accuracy demand, the way to use a linear CCD camera measuring the distance of the double light curtains is presented, the double light curtains has been projected from array LED light source to the aperture of the receiving device. According to the image processing algorithm, the middle distance of the double light curtains has been calculated, the new method of high accuracy distance measurement has been achieved, the distance measurement system and algorithm has been studied.Firstly, the spatial distribution of dual screen in double-slit light screen has been analyzed. According to the technical indicator, the whole scheme of the distance measurement system has been designed. The working principle and component of the measurement has been introduced in detail. At the same time, the selection of the key components of the CCD camera, camera lens, one-dimensional linear motion guide has been completed.Secondly, the working principle of double-slit light screen has been analyzed. The function and structure of the device of transmit and receive in double-slit light screen has been introduced. According to the overall plan of the measurement system, it gave out the structure of the movable camera support mechanism, vertical fixed, camera fixed pasts, adjustable flat base. Through the distance measurement system has been accurately installed and aligned; the real-time acquisition of the double curtains has been completed.Thirdly, according to the characteristics of the image information of the double curtains has collected. In image pre-processing, the median filtering method is used. In the threshold segmentation, the Otsu threshold method is used. In curve fitting, the method of least squares is used. For double curtains in an ideal state, the algorithm has been proposed in this paper, the center distance of double curtains has been accurately extracted. According to the double curtains in non ideal state, the new algorithm of the image detection and recognition has also been proposed in this paper, the trapezoidal distortion screen has been detected.Finally, according to the prototype in the size of 300×150mm and the distance measurement system are achieved. After the validation experiments, the analysis of the influence of each error source for precision of distance measurement, the results show that the distance measurement method is feasible, the non parallel light curtain also has been recognized and detected through this method.