红枣收获机视觉导航路径检测

    Path detection of visual navigation for jujube harvesters

    • 摘要: 针对新疆地区骏枣与灰枣枣园的收获作业,该研究提出一种红枣收获机枣树行视觉导航路径检测算法。通过枣园图像固定区域中B分量垂直累计直方图的标准差d与最小值f的关系对枣园种类进行自动判断。针对灰枣枣园,首先采用色差法与OTSU法对图像进行灰度化与二值化处理,然后进行面积去噪与补洞处理,在处理区域内从上向下逐行扫描,将每行像素上像素值为0的像素点坐标平均值作为该行候补点的坐标,并将所有候补点坐标的平均值作为Hough变换的已知点坐标,最后基于过已知点的Hough变换拟合导航路径;针对骏枣枣园,在处理区域内通过垂直累计R分量的方法确定扫描区间,然后在扫描区间内从上到下逐行扫描,将每行像素上R分量值最小的像素点作为该行的候补点,并将所有候补点的坐标平均值作为Hough变换的已知点,最后使用过已知点的Hough变换拟合导航路径。试验结果表明:对于灰枣枣园与骏枣枣园,该算法的路径检测准确率平均值分别为94%和93%,处理1帧图像平均耗时分别为0.042和0.046 s,检测准确性与实时性满足红枣收获机作业要求,能够自动判别枣园种类进行作业,可为实现红枣收获机自动驾驶提供理论依据。

       

      Abstract: The jujube industry occupies an important position in the social economy of Xinjiang. It is important to realize the automatic driving of the jujube harvester. This study proposes a visual navigation path detection algorithm for the jujube harvester which working above the jujube trees based on image processing, aiming at the harvest operation of the Jun-jujube and Hui-jujube orchards in Xinjiang. First, the variety of the jujube orchard was distinguished. Set the middle 1/3 area in the y-axis direction of the image as the processing area, according to the relationship between the standard deviation d and the minimum value f of the B-component vertical cumulative histogram of the processing area of the image, the jujube orchard variety was automatically determined. If the value of f/d was less than 5, it was the Jun-jujube orchard, and the rest was the Hui-jujube orchard. Secondly, navigation path was extracted based on the results of jujube orchard classification. For the Hui-jujube orchard, the cromatic aberration method and the OTSU method weare first used to transform the image into gray and binary, and then to denoise and fill the pixel hole that the black pixels inside white pixels or the white pixels inside black pixels in the binary image. Then, the pixel rows were scanned from the top to the bottom in the processing area, and then the coordinates average value of the pixel points with pixel value of 0 were taken as the candidate points on each pixel row, and the average value of all candidate points' coordinates was used as the known point coordinates of Hough transform. Finally, the navigation path was fitted based on the Hough transform through the known points. For the Jun-jujube orchard, set the middle 1/3 of the X-axis direction of the image as the processing area. The scan interval was determined by vertically accumulating the R-component in the processing area. Then, in the processing area, the scanning interval was determined by accumulating R-component vertically, and then scanned line by line from top to bottom in the scanning area,,the pixel with the smallest R-component value in each row of pixels was taken as the candidate point of the line, and the average coordinate value of all candidate points was taken as the known point of Hough transform. Finally, the Hough transform of known points was used to fit the navigation path The test results showed that for the Hui-jujube orchard and the Jun-jujube orchard, the average path detection accuracy of the algorithm was 94% and 93%, and the average processing time of one frame image was 0.042 and 0.046 s respectively. The detection accuracy and real-time performance can meet the requirements of jujube harvester operation, and can automatically identify the types of jujube orchard for operation, which can provide theoretical basis for the realization of automatic driving of jujube harvester.

       

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