图像匹配导致图像不应该是一个（Python opencv 教程）

Question

我正在使用 following python opencv 示例：

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread('messi5.jpg',0)
img2 = img.copy()
template = cv2.imread('template.jpg',0)
w, h = template.shape[::-1]

# All the 6 methods for comparison in a list
methods = ['cv2.TM_CCOEFF', 'cv2.TM_CCOEFF_NORMED', 'cv2.TM_CCORR',
            'cv2.TM_CCORR_NORMED', 'cv2.TM_SQDIFF', 'cv2.TM_SQDIFF_NORMED']

for meth in methods:
    img = img2.copy()
    method = eval(meth)

    # Apply template Matching
    res = cv2.matchTemplate(img,template,method)
    min_val, max_val, min_loc, max_loc = cv2.minMaxLoc(res)

    # If the method is TM_SQDIFF or TM_SQDIFF_NORMED, take minimum
    if method in [cv2.TM_SQDIFF, cv2.TM_SQDIFF_NORMED]:
        top_left = min_loc
    else:
        top_left = max_loc
    bottom_right = (top_left[0] + w, top_left[1] + h)

    cv2.rectangle(img,top_left, bottom_right, 255, 2)

    plt.subplot(121),plt.imshow(res,cmap = 'gray')
    plt.title('Matching Result'), plt.xticks([]), plt.yticks([])
    plt.subplot(122),plt.imshow(img,cmap = 'gray')
    plt.title('Detected Point'), plt.xticks([]), plt.yticks([])
    plt.suptitle(meth)

    plt.show()

匹配在一组选定的图像上效果很好，这些图像清楚地包含模板。我的问题是，即使在明显不包含模板的图像中，也会绘制一个矩形。我怎样才能适应源代码，所以它可以处理根本不匹配的图像。

提前致谢

Answer 1

文档中：

It returns a grayscale image, where each pixel denotes how much does the neighbourhood of that pixel match with template

所以为res设置一个阈值，如果图像中没有相似性，它什么都不做。

res = cv2.matchTemplate(img,template,method)
if res<0.8:
    return
...

就像在 Template Matching with Multiple Objects part

Answer 2

您的代码始终显示最佳匹配，无论匹配有多好。

您可以检查 max_val 的值（或 min_val 当使用 SQDIFF 时），并且仅当该值超过特定阈值时才显示匹配项。

图像匹配导致图像不应该是一个（Python opencv 教程）

Image Matching result in images where it shouldn't be one (Python opencv tutorial)

python

opencv

image

template-matching