colors - How to find HSV values from a certain area as average in a video, python?

Question

I'd like to extract the lower and upper of HSV values from area after click and crop it by mouse in video instead of an image.

Note: if you run this code, press key "c" to see the values.

The source of the code: here or here with a good explanation how to work, he creates a good code to find them in video here but I'd like to use the mouse to extract them as average similar to this code.

I did it by image, but I'd like to use it in video.

How to convert it from image to video?

The full code.

import cv2
import numpy as np

x_start, y_start, x_end, y_end = 0, 0, 0, 0
cropping = False
getROI = False
refPt = []



# load the image, clone it, and setup the mouse callback function
image = cv2.imread('exp2.png')
clone = image.copy()




def click_and_crop(event, x, y, flags, param):
    # grab references to the global variables
    global x_start, y_start, x_end, y_end, cropping, getROI

    # if the left mouse button was clicked, record the starting
    # (x, y) coordinates and indicate that cropping is being
    # performed
    if event == cv2.EVENT_LBUTTONDOWN:
        x_start, y_start, x_end, y_end = x, y, x, y
        cropping = True

    elif event == cv2.EVENT_MOUSEMOVE:
        if cropping == True:
            x_end, y_end = x, y

    # check to see if the left mouse button was released
    elif event == cv2.EVENT_LBUTTONUP:
        # record the ending (x, y) coordinates and indicate that
        # the cropping operation is finished
        x_end, y_end = x, y
        cropping = False
        getROI = True


cv2.namedWindow("image")
cv2.setMouseCallback("image", click_and_crop)

# keep looping until the 'q' key is pressed
while True:


    i = image.copy()


    if not cropping and not getROI:
        cv2.imshow("image", image)
        # print 'fff'

    elif cropping and not getROI:
        cv2.rectangle(i, (x_start, y_start), (x_end, y_end), (0, 255, 0), 2)
        cv2.imshow("image", i)
        # print 'bbb'

    elif not cropping and getROI:
        cv2.rectangle(image, (x_start, y_start), (x_end, y_end), (0, 255, 0), 2)
        cv2.imshow("image", image)
        # print 'mmm'

    key = cv2.waitKey(1) & 0xFF

    # if the 'r' key is pressed, reset the cropping region
    if key == ord("r"):
        image = clone.copy()
        getROI = False

    # if the 'c' key is pressed, break from the loop
    elif key == ord("c"):   # please press "c" key to get values.
        break

# if there are two reference points, then crop the region of interest
# from teh image and display it
refPt = [(x_start, y_start), (x_end, y_end)]
# print len(refPt)
if len(refPt) == 2:
    roi = clone[refPt[0][1]:refPt[1][1], refPt[0][0]:refPt[1][0]]
    cv2.imshow("ROI", roi)

    hsvRoi = cv2.cvtColor(roi, cv2.COLOR_BGR2HSV)
    print('min H = {}, min S = {}, min V = {}; max H = {}, max S = {}, max V = {}'.format(hsvRoi[:, :, 0].min(),
                                                                                          hsvRoi[:, :, 1].min(),
                                                                                          hsvRoi[:, :, 2].min(),
                                                                                          hsvRoi[:, :, 0].max(),
                                                                                          hsvRoi[:, :, 1].max(),
                                                                                          hsvRoi[:, :, 2].max()))

    lower = np.array([hsvRoi[:, :, 0].min(), hsvRoi[:, :, 1].min(), hsvRoi[:, :, 2].min()])
    upper = np.array([hsvRoi[:, :, 0].max(), hsvRoi[:, :, 1].max(), hsvRoi[:, :, 2].max()])

    image_to_thresh = clone
    hsv = cv2.cvtColor(image_to_thresh, cv2.COLOR_BGR2HSV)

    kernel = np.ones((3, 3), np.uint8)
    # for red color we need to masks.
    mask = cv2.inRange(hsv, lower, upper)
    mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel)
    mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)

    cv2.imshow("Mask", mask)
    cv2.waitKey(0)
# close all open windows
    cv2.destroyAllWindows()

Please help me.

Thanks in advance.

Answer 1

after the

cv2.namedWindow("image")
cv2.setMouseCallback("image", click_and_crop)

replace your while True: with:

video_path = "your_video.mp4"
cap = cv2.VideoCapture(video_path)

while(cap.isOpened()):
    ret, image = cap.read()

So the now the image is your frame from the video.