Application And Research Of Image Fusion Technology In Sheep Body Size Measurement

Sheep body size data, such as height, length, hip width and so on, directly reflect thesize of the sheep body and the situation of growth. Most of the current methods are stillpersonally measurement by the meter stick, tape, etc. The measurement results aremanually recorded which is a heavy task. In recent years, a number of studies on livestockbody size measurements based on machine vision are on research. Background subtraction,threshold segmentation method are commonly used in the extraction of livestock contour.However, in the practical application of contour extraction with color, light and otherinterference, background subtraction result is bad and threshold is much difficult to choice,so that the outline of target sheep can’t be separated. When a certain angle exists betweenthe sheep body posture plane and image plane, the sheep body size data is not real,generally smaller than the true value. Obviously, using color image alone can neitherobtain the sheep body space contour precisely nor be rectified.To solve the problem of bad background subtraction result and hard–determinedthreshold caused by complex background and color interference, Kinect sensor as theimage acquisition device is used to acquire the sheep color image and depth image aftercalibrated, achieving the fusion of multi-source data. Color and depth information can getby two kind images. Because depth information is not affected by light or color and colorinformation is not affected by depth, sheep body contour is gained precisely by the way ofcolor and depth fusion. After median filtering and threshold segmentation, the sheep bodyregion is extracted from original image by pixel expansion method and the sheep bodyclosed contour is gotten.In feature extraction of sheep body contour, analyzing the contour with U-chordcurvature at the corresponding position on the back line, and the maximum curvature pointis the position of the buttocks. In order to ensure the accuracy of the search process, thefoot points can be gotten by scanning from the button of the image. With the association ofthe foot points position, the neck point is gotten. To solve the problem of standing interference, sheep body space contour is gottenbased on depth information of the sensor. The sheep body contour fitting plane isestablished according to the sample point. Sheep body size data is calculated on the fittingsurface according feature point to rectify standing posture. Finally, measure system is builtbased on VS2010, Windows SDK and OpenCV. The test results show the proposed methodcan accurately measure the sheep body size, and the relative error is within4.3%.