How to draw rectangles around every blue object?-CodePudding

I have found lots of information about how to draw rectangles around the biggest blue object in the frame but I need to draw rectangles around all of the blue objects.

This is my current code

import numpy as np
import cv2  

cap = cv2.VideoCapture(0)

while True:
    _, frame = cap.read()
    # Convert BGR to HSV
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
    # define range of blue color in HSV
    lower_blue = np.array([100,50,50])
    upper_blue = np.array([130,255,255])
    # Threshold the HSV image to get only blue colors
    mask = cv2.inRange (hsv, lower_blue, upper_blue)
    bluecnts = cv2.findContours(mask.copy(),
                              cv2.RETR_EXTERNAL,
                              cv2.CHAIN_APPROX_SIMPLE)[-2]


    if len(bluecnts)>0:
        blue_area = max(bluecnts, key=cv2.contourArea)
        print(blue_area)
        (xg,yg,wg,hg) = cv2.boundingRect(blue_area)
        cv2.rectangle(frame,(xg,yg),(xg wg, yg hg),(0,255,0),2)

    result = cv2.bitwise_and(frame, frame, mask=mask)

    cv2.imshow('frame',frame)
    cv2.imshow('mask',mask)
    cv2.imshow('blue', result)

    if cv2.waitKey(1) == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

And this is what it currently does, draw one rectangle around the biggest blue object but I need it around each one.

One Blue Rectangle

CodePudding user response：

In your Python/OpenCV code, try replacing

   if len(bluecnts)>0:
        blue_area = max(bluecnts, key=cv2.contourArea)
        print(blue_area)
        (xg,yg,wg,hg) = cv2.boundingRect(blue_area)
        cv2.rectangle(frame,(xg,yg),(xg wg, yg hg),(0,255,0),2)

with

   if len(bluecnts)>0:
        for cnt in bluecnts:
            area = cv2.contourArea(cnt)
            print(area)
            (xg,yg,wg,hg) = cv2.boundingRect(cnt)
            cv2.rectangle(frame,(xg,yg),(xg wg, yg hg),(0,255,0),2)

(Untested)