matchTemplate (-215:Assertion failed) corr.rows <= img.rows + templ.rows - 1 && corr.cols <= img.cols + templ.cols - 1 in function 'cv::crossCorr'

问题描述

我在 python 中使用模板匹配进行对象检测。 给定两张图片，一张源图片和一张模板图片，我打算在背景图片中找到模板图片匹配的位置。

函数代码：

def __init__(self,piece_path,background_path):
    self.piece_path = piece_path
    self.background_path = background_path

def __img_to_grayscale(self,img):
    tmp_path = "/tmp/sobel.png"
    cv2.imwrite(tmp_path,img)
    return cv2.imread(tmp_path,0)

def get_position(self):
    # some code for template and background processing
    background = self.__img_to_grayscale(self.background_path)
    template = self.__img_to_grayscale(self.piece_path)

    res = cv2.matchTemplate(background,template,cv2.TM_CCOEFF_norMED)
    min_val,max_val,min_loc,max_loc = cv2.minMaxLoc(res)
    top_left = max_loc

    origin = x_inf
    end = top_left[0] + PIXELS_EXTENSION
    
    return end - origin

输入： bg.png 是 76 kb 并且 12 kb 的模板.png

解决方法

确保在每个位置使用的文件路径（绝对/相对）遵循操作系统约定。

对于 Linux：

def __img_to_grayscale(self,img):
    tmp_path = "/tmp/sobel.png"
    cv2.imwrite(tmp_path,img)
    return cv2.imread(tmp_path,0)

对于 Windows：

def __img_to_grayscale(self,img):
    tmp_path = "../sobel.png"
    cv2.imwrite(tmp_path,0)