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Object tracking using OpenCV ..I am not able to understand some part of code

asked 2017-12-16 18:22:52 -0500

KRK gravatar image

updated 2017-12-17 08:39:21 -0500

berak gravatar image

Hello, I am completely new to OpenCV, I am also a bit afraid of asking so basic questions ..I hope I would be helped......Questions: a). Didn't understood this part of code..

# Bitwise-AND mask and original image
res = cv2.bitwise_and(frame,frame, mask= mask)

k = cv2.waitKey(5) & 0xFF
if k == 27:
    break


import cv2
import numpy as np

cap = cv2.VideoCapture(0)

while(1):

    # Take each frame
    _, 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([110,50,50])
    upper_blue = np.array([130,255,255])

    # Threshold the HSV image to get only blue colors
    mask = cv2.inRange(hsv, lower_blue, upper_blue)

    # Bitwise-AND mask and original image
    res = cv2.bitwise_and(frame,frame, mask= mask)

    cv2.imshow('frame',frame)
    cv2.imshow('mask',mask)
    cv2.imshow('res',res)
    k = cv2.waitKey(5) & 0xFF
    if k == 27:
        break

cv2.destroyAllWindows()
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answered 2017-12-18 04:02:13 -0500

supra56 gravatar image

Here is example that make you understand: Drawing and Bitwise Operations

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answered 2017-12-17 14:12:16 -0500

ArkadiuszRaj gravatar image

Usually mask is used to limit area of image for some operation. Like copying fragment of original image, or applying some math operation.

In this case bitwise operation is used to not alter image itself, but to extract only part of it (mask) and copy to res variable.

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Asked: 2017-12-16 18:22:52 -0500

Seen: 140 times

Last updated: Dec 18 '17