Research On Parking Slot Detection Technology Based On Panoramic Around View System

Aiming at the shortcomings of the broken stitching line segments in the panoramic image,based on the extensive understanding of the domestic and foreign literatures,the Around View Monitor(AVM)systems is built.The effects of different fusion algorithms and different splicing areas on the generation of AVM image are analyzed.The detection and recognition algorithm of "U-shaped" parking slot based on AVM image is studied,which provides a reference for parking slot detection technology based on vision sensor.The work is composed of the following aspects:(1)The fisheye camera model and the calibration principle of internal and external parameters of the fisheye camera is introduced.Among them,the fisheye camera model approximates the equidistant projection model,and deduces the process of imaging a point in the space to the fisheye image.The Zhang Zhengyou calibration algorithm is used to calibrate the camera internal parameters,the conversion relationship between the four around-view camera image coordinate systems and the same world coordinate system is calculated to calibrate the camera external parameters.(2)The effect of the top-view transformation of the trigonometric function method and the checkerboard calibration method is analyzed.The four around-view camera is transformed into a top view to obtain a top view of the camera.In order to speed up the splicing speed,the splicing method based on the pixel lookup table is used to save the conversion relationship between the around-view image and the top view image,and only need to carry the pixel points in the image coordinate system to the top-view image corresponding pixel position for each splicing.The influence of different splicing area selection on the splicing seam was studied.Finally,the splicing area was fused by weighted average fusion algorithm.(3)According to the requirements of the parking slot detection algorithm,the influence of Hough transform and LSD(Line Segment Detector)based line detection algorithm on the detection accuracy of parking slot detection is analyzed.For the large number of "U-shaped" parking slots in the parking lot,the algorithm is designed to filter out the interference line and extract corners of the parking slot,fits the effective parking slot.When the vehicle is in the process of running,the phenomenon of missed detection often occurs.The parking slot is tracked by optical flow tracking algorithm,and the design flow of the parking slot detection system is determined.(4)According to the requirements of parking slot detection,an parking slot detection system based on panoramic around view is built.In order to verify the effectiveness of the algorithm,experimental tests are carried out on different parking scenarios,including sunny and rainy days,underground parking slot and above-ground parking slot.Experimental testing and comparative analysis were carried out on the detection and recognition effects.The experimental results show that the parking slot detection algorithm is suitable for most weather and parking scenarios,and can effectively detect the parking slot and reduce missed detection and false detection.