ch8.py

import cv2
import numpy as np
#Note detecting shapes and identify shapes..
def stackImages(scale,imgArray):
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range ( 0, rows):
            for y in range(0, cols):
                if imgArray[x][y].shape[:2] == imgArray[0][0].shape [:2]:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (0, 0), None, scale, scale)
                else:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]), None, scale, scale)
                if len(imgArray[x][y].shape) == 2: imgArray[x][y]= cv2.cvtColor( imgArray[x][y], cv2.COLOR_GRAY2BGR)
        imageBlank = np.zeros((height, width, 3), np.uint8)
        hor = [imageBlank]*rows
        hor_con = [imageBlank]*rows
        for x in range(0, rows):
            hor[x] = np.hstack(imgArray[x])
        ver = np.vstack(hor)
    else:
        for x in range(0, rows):
            if imgArray[x].shape[:2] == imgArray[0].shape[:2]:
                imgArray[x] = cv2.resize(imgArray[x], (0, 0), None, scale, scale)
            else:
                imgArray[x] = cv2.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None,scale, scale)
            if len(imgArray[x].shape) == 2: imgArray[x] = cv2.cvtColor(imgArray[x], cv2.COLOR_GRAY2BGR)
        hor= np.hstack(imgArray)
        ver = hor
    return ver

def getContours(img):
    contours,hierarchy = cv2.findContours(img,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE)#outlines or bounding shapes..
    for cnt in contours:
        area = cv2.contourArea(cnt)#get total area of shapes..
        print(area)
        if area>500:
            cv2.drawContours(imgContour, cnt, -1, (255, 0, 0), 3)#draw baoundry on area
            peri = cv2.arcLength(cnt,True)#get arc/lenth of shape
            #print(peri)
            approx = cv2.approxPolyDP(cnt,0.02*peri,True)#get no of corner points
            print(len(approx))
            objCor = len(approx)
            x, y, w, h = cv2.boundingRect(approx)

            if objCor ==3: objectType ="Tri"
            elif objCor == 4:
                aspRatio = w/float(h)
                if aspRatio >0.98 and aspRatio <1.03: objectType= "Square"
                else:objectType="Rectangle"
            elif objCor>4: objectType= "Circles"
            else:objectType="None"



            cv2.rectangle(imgContour,(x,y),(x+w,y+h),(0,255,0),2)#draw rectangle on shapes..
            cv2.putText(imgContour,objectType,
                        (x+(w//2)-10,y+(h//2)-10),cv2.FONT_HERSHEY_COMPLEX,0.7,
                        (0,0,0),2)#put text of each shapes..




path = 'Resources/shapes.png'
img = cv2.imread(path)
imgContour = img.copy()

imgGray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)#convert into gray image
imgBlur = cv2.GaussianBlur(imgGray,(7,7),1)#make blur image
imgCanny = cv2.Canny(imgBlur,50,50)#make canny image
getContours(imgCanny)

imgBlank = np.zeros_like(img)
imgStack = stackImages(0.7,([img,imgGray,imgBlur],
                            [imgCanny,imgContour,imgBlank]))

cv2.imshow("Stack", imgStack)

cv2.waitKey(0)