project2.py

import cv2
import numpy as np

widthImg = 480
heightImg = 640

cap = cv2.VideoCapture(0) #0 means the default camera
cap.set(3,640) #setting height of camera
cap.set(4,480) #setting width of camera
cap.set(10,150) #setting the brightness of the webcam

def preProcessing(img):
    imgGray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    imgBlur = cv2.GaussianBlur((imgGray),(5,5),1)
    imgCanny = cv2.Canny(imgBlur,200,200)
    kernel = np.ones((5,5))
    imgDial = cv2.dilate(imgCanny,kernel,iterations=2)
    imgThres = cv2.erode(imgDial,kernel,iterations=1)

    return imgThres

def getContours(img):
    biggest = np.array([])
    maxArea = 0
    contours, hierarchy = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
    for cnt in contours:
        area = cv2.contourArea(cnt)
        if area>5000:
            # cv2.drawContours(imgContour, cnt, -1, (255,0,0),3)
            peri = cv2.arcLength(cnt, True)
            approx = cv2.approxPolyDP(cnt, 0.02*peri, True)
            if area>maxArea and len(approx) == 4:
                biggest = approx
                maxArea = area
    cv2.drawContours(imgContour, biggest, -1, (255,0,0), 20)
    return biggest

def reorder(myPoints):
    myPoints = myPoints.reshape((4,2))
    myPointsNew = np.zeros((4,1,2),np.int32)
    add = myPoints.sum(1)
    # print("add", add)

    myPointsNew[0] = myPoints[np.argmin(add)]
    myPointsNew[3] = myPoints[np.argmax(add)]
    diff = np.diff(myPoints,axis=1)
    myPointsNew[1] = myPoints[np.argmin(diff)] 
    myPointsNew[2] = myPoints[np.argmax(diff)] 
    print("NewPoints",myPointsNew)
    return myPointsNew
       

def getWarp(img,biggest):
    biggest = reorder(biggest)
    pts1 = np.float32(biggest)
    pts2 = np.float32([[0,0],[widthImg,0],[0,heightImg],[widthImg,heightImg]])
    matrix = cv2.getPerspectiveTransform(pts1,pts2)
    imgOutput = cv2.warpPerspective(img,matrix,(widthImg,heightImg))

    imgCropped = imgOutput[20:imgOutput,shape[0]-20,20:imgOutput.shape[1]-20]
    imgCropped = cv2.resize(imgCropped,(widthImg,heightImg))

    return imgCropped



while True:
    success, img =cap.read()
    cv2.resize(img,(widthImg,heightImg))
    imgContour = img.copy()


    imgThres = preProcessing(img)
    biggest = getContours(imgThres)
    # print(biggest)
    imgWarped=getWarp(img,biggest)


    cv2.imshow("Result", imgWarped)
    if cv2.waitKey(1) & 0xFF ==ord('q'): 
        break