added shape detection python script

Author: NEEHITGOYAL

Python/shape-detection/images/Test1.png

@@ -0,0 +1,202 @@
+import cv2
+import numpy as np
+import os
+shapes = {}
+#calculates the area of the shape
+
+def area(cnt):
+    area = cv2.contourArea(cnt)
+    return area     
+                      
+#calculates the centroids of the shape
+                                                             
+def centroids(cnt):
+    M = cv2.moments(cnt)
+    cx = int(M['m10']/M['m00'])
+    cy = int(M['m01']/M['m00'])
+    #print(cx,cy)
+    return cx,cy         
+
+
+if __name__ == '__main__':
+    global shapes
+    img = cv2.imread("img.png",0)
+    image = cv2.imread("img.png")
+    h_img,w_img=img.shape
+    shapes = {} #creates an empty dictionary
+        
+    ret,thresh = cv2.threshold(img , 240, 255, cv2.THRESH_BINARY)#calculates threshold of the gray image
+    contours,hierarchy= cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
+    
+    
+                                
+    for cnt in contours:#loops through each shape
+        approx = cv2.approxPolyDP(cnt, 0.01*cv2.arcLength(cnt, True), True)#it approximates a contour shape 
+        cv2.drawContours(image , [approx], 0, (0), 5)
+        x = approx.ravel()[0]
+        y = approx.ravel()[1]
+
+        if len(approx) == 3:
+            shapes["Triangle"]=[]#initialising the key "Triangle" with an empty list
+            
+            ar=area(cnt)#calling area function
+            cx,cy=centroids(cnt)#calling centroids function
+            color = image[cy,cx]#gives pixels of point(cx,cy) 
+            blue,green,red=color#unpacking of tuple
+
+            m=max(blue,green,red)
+            if color[0]==m:
+                col="blue"
+            elif color[1]==m:
+                col= "green"
+            else:
+                col="red"
+            shapes["Triangle"].append(col)#appending the list with property color 
+            shapes["Triangle"].append(ar)#appending the list with property area 
+
+            shapes["Triangle"].append(cx)#appending the list with property cx 
+
+            shapes["Triangle"].append(cy)#appending the list with property cy
+
+            
+        elif len(approx) == 4 : 
+            (x, y, w, h) = cv2.boundingRect(approx)# to highlight the region of interest 
+            arr = w / float(h)#calculates aspect ratio
+            areaa=area(cnt)
+            if arr >= 0.95 and arr <= 1.05 and w<(w_img-10) :#if aspect ratio is approximately equal to one then it is a square
+#w<1000 because the w of the whole image is 1024 
+        
+                shapes["Square"]=[]
+                ar=area(cnt)
+                cx,cy=centroids(cnt)
+                color = image[cy,cx]
+                blue,green,red=color
+
+                m=max(blue,green,red)
+                if color[0]==m:
+                    col="blue"
+                elif color[1]==m:
+                    col= "green"
+                else:
+                    col="red"
+                shapes["Square"].append(col)    
+                shapes["Square"].append(ar)
+                shapes["Square"].append(cx)
+                shapes["Square"].append(cy)        
+            elif(w<(w_img-10) and areaa>=0.99*w*h):
+                shapes["Rectangle"]=[]
+                ar=area(cnt)
+                cx,cy=centroids(cnt)
+                color = image[cy,cx]
+                blue,green,red=color
+
+                m=max(blue,green,red)
+                if color[0]==m:
+                    col="blue"
+                elif color[1]==m:
+                    col= "green"
+                else:
+                    col="red"
+                shapes["Rectangle"].append(col)    
+                shapes["Rectangle"].append(ar)
+                shapes["Rectangle"].append(cx)
+                shapes["Rectangle"].append(cy)
+
+            elif(w<(w_img-10)):
+                shapes["Rhombus"]=[]
+                ar=area(cnt)
+                cx,cy=centroids(cnt)
+                color = image[cy,cx]
+                blue,green,red=color
+
+                m=max(blue,green,red)
+                if color[0]==m:
+                    col="blue"
+                elif color[1]==m:
+                    col= "green"
+                else:
+                    col="red"
+                shapes["Rhombus"].append(col)    
+                shapes["Rhombus"].append(ar)
+                shapes["Rhombus"].append(cx)
+                shapes["Rhombus"].append(cy)
+           
+            
+        elif len(approx) == 5:
+            shapes["Pentagon"]=[]
+            ar=area(cnt)
+            cx,cy=centroids(cnt)
+            color = image[cy,cx]
+            blue,green,red=color
+
+            m=max(blue,green,red)
+            if color[0]==m:
+                col="blue"
+            elif color[1]==m:
+                col= "green"
+            else:
+                col="red"
+            shapes["Pentagon"].append(col)
+            shapes["Pentagon"].append(ar)
+            shapes["Pentagon"].append(cx)
+            shapes["Pentagon"].append(cy)
+        elif len(approx) == 6:
+            shapes["Hexagon"]=[]
+            ar=area(cnt)
+            cx,cy=centroids(cnt)
+            color = image[cy,cx]
+            blue,green,red=color
+
+            m=max(blue,green,red)
+            if color[0]==m:
+                col="blue"
+            elif color[1]==m:
+                col= "green"
+            else:
+                col="red"
+            shapes["Hexagon"].append(col)
+            shapes["Hexagon"].append(ar)
+            shapes["Hexagon"].append(cx)
+            shapes["Hexagon"].append(cy)    
+        elif 6 < len(approx) < 15:
+            shapes["Ellipse"]=[]
+            ar=area(cnt)
+            cx,cy=centroids(cnt)
+            color = image[cy,cx]
+            blue,green,red=color
+
+            m=max(blue,green,red)
+            if color[0]==m:
+                col="blue"
+            elif color[1]==m:
+                col= "green"
+            else:
+                col="red"
+            shapes["Ellpise"].append(col)
+            shapes["Ellpise"].append(ar)
+            shapes["Ellpise"].append(cx)
+            shapes["Ellpise"].append(cy)
+        else:
+#if contour has no vertex then it is a circle
+            shapes["Circle"]=[]
+            ar=area(cnt)
+            cx,cy=centroids(cnt)
+            color = image[cy,cx]
+            blue,green,red=color
+
+            m=max(blue,green,red)
+            if color[0]==m:
+                col="blue"
+            elif color[1]==m:
+                col= "green"
+            else:
+                col="red"
+            shapes["Circle"].append(col)
+            shapes["Circle"].append(ar)
+            shapes["Circle"].append(cx)
+            shapes["Circle"].append(cy)
+
+
+  
+    
+    print(shapes)