userblock25 userblock25 - 1 month ago 25
Python Question

Error at template matching in OpenCV-Python

I'm trying to template matching using my web cam.I used web cam feed as source and used a template as small image that taken from web cam. Both template and source have same bit depth.(uint8).

I'm using OpenCV3.0 with python 2.7 in VS 2013 IDE I got this error:


C:\builds\master_PackSlaveAddon-win32-vc12-static\opencv\modules\imgproc\src\templmatch.cpp:1062: error: (-215) (depth == CV_8U || depth == CV_32F) && type == _templ.type() && _img.dims() <= 2 in function cv::matchTemplate


This is my code:

import cv2
import numpy as np

cam=cv2.VideoCapture(1)
template = cv2.imread("C:/Users/user/Desktop/ttt.jpg",0)
w, h = template.shape[::-1]

method=cv2.TM_CCOEFF_NORMED

while 1:
_,img=cam.read()
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)

cv2.imshow('img',img)


if cv2.waitKey(1) & 0xFF == ord('q'):
cv2.destroyAllWindows

Answer

Convert source image to gray

while 1:
_,img=cam.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # !!
res = cv2.matchTemplate(gray, template,method)
min_val, max_val, min_loc, max_loc = cv2.minMaxLoc(res)
...
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