my OpenCV color detection (red) program doesn't work. it detects all colors instead of red-CodePudding

import numpy as np
import cv2

img=cv2.imread('image.jpg')

hsvFrame=cv2.cvtColor(img ,cv2.COLOR_BGR2HSV)

#SET RANGE FOR RED
#DEFINE MASk

red_lower=np.array([0,0,204],np.uint8)
red_upper=np.array([0,0,255],np.uint8)
red_mask=cv2.inRange(hsvFrame,red_lower,red_upper)
kernel=np.ones((5,5),"uint8")
red_mask=cv2.dilate(red_mask,kernel)
res_red=cv2.bitwise_and(img,img,mask=red_mask)

#creating contour

contours,hierarchy=cv2.findContours(red_mask,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

for pic,contour in enumerate(contours):

    area=cv2.contourArea(contour)
    if area>300:
        x,y,w,h=cv2.boundingRect(contour)
        imageFrame=cv2.rectangle(img,(x,y),(x w,y h),(0,0,255),2)

        cv2.putText(img,"red colour",(x,y),
        cv2.FONT_HERSHEY_SIMPLEX,1.0,(0,0,255))

cv2.imshow("detected red ",img)
cv2.waitKey(0)

tried to detect red color in a given image but the program detects other colors. converted this program from a program that detects red color from the webcam feed and it works fine, but the red detection in images doesn't work

CodePudding user response：

Why are you converting your image to HSV? There appears to be a mismatch between the color range you are trying to match (which appears to be specified in BGR color space) vs the color space your image is in (HSV). I suspect that is the source of your issue.