chapter1.py

import cv2.cv2 as cv2
import numpy as np

# READ WEBCAM #
frameWidth = 640
frameHeight = 480
cap = cv2.VideoCapture(0)
cap.set(3, frameWidth)
cap.set(4, frameHeight)
cap.set(10, 130)  # brightness

# orange green purple
myColors = [[0, 187, 6, 149, 214, 255],
            [38, 134, 68, 132, 214, 255],
            [98, 109, 43, 142, 202, 202]]

# BGR
myColorValues = [[51, 153, 255],
                 [0, 255, 0],
                 [255, 0, 255]]

myPoints = []


# to detect color
def findColor(img, myColors, myColorValues):
    imgHSV = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
    count = 0
    newPoints = []
    for color in myColors:
        lower = np.array(color[0:3])
        upper = np.array(color[3:6])
        mask = cv2.inRange(imgHSV, lower, upper)
        x, y = getContours(mask)
        cv2.circle(imgResult, (x, y), 10, myColorValues[count], cv2.FILLED)
        if x != 0 and y != 0:
            newPoints.append([x, y, count])
        count += 1
    return newPoints

    # cv2.imshow(str(color[0]),mask)


# to create bounding box
def getContours(img):
    contours, hierarchy = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
    x, y, w, h = 0, 0, 0, 0
    for cnt in contours:
        area = cv2.contourArea(cnt)
        if area > 500:
            # cv2.drawContours(imgResult, cnt, -1, (255, 0, 0), 4)
            perimeter = cv2.arcLength(cnt, True)
            approx = cv2.approxPolyDP(cnt, 0.02 * perimeter, True)
            x, y, w, h = cv2.boundingRect(approx)
    return x + w // 2, y


# to draw
def drawOnCanvas(myPoints, myColorValues):
    for point in myPoints:
        cv2.circle(imgResult, (point[0], point[1]), 10, myColorValues[point[2]], cv2.FILLED)


while True:
    success, img = cap.read()
    imgResult = img.copy()
    newPoints = findColor(img, myColors, myColorValues)
    if len(newPoints) != 0:
        for newP in newPoints:
            myPoints.append(newP)
    if len(myPoints) != 0:
        drawOnCanvas(myPoints, myColorValues)
    # cv2.imshow("Output",img)
    cv2.imshow("Contour", imgResult)
    if cv2.waitKey(1) & 0xFF == ord('Q'):
        break