023 - Mini Project 2 - Identifying Contours by Shape.ipynb

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    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "#Load and then grayscale the image\n",
    "image = cv2.imread(\"images/project01.png\")\n",
    "gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)\n",
    "\n",
    "cv2.imshow(\"Identifying Shapes\",image)\n",
    "cv2.waitKey()\n",
    "\n",
    "ret, thresh = cv2.threshold(gray, 127, 255, 1)\n",
    "\n",
    "#Extract contours\n",
    "_,contours, hierarchy = cv2.findContours(thresh.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_NONE)\n",
    "\n",
    "for cnt in contours:\n",
    "    \n",
    "    #Get approximate polygons\n",
    "    approx = cv2.approxPolyDP(cnt, 0.01*cv2.arcLength(cnt,True),True)\n",
    "    \n",
    "    if len(approx)==3:\n",
    "        shape_name=\"Triangle\"\n",
    "        cv2.drawContours(image,[cnt],0,(0,255,0),-1)\n",
    "        \n",
    "        #Find contour center to place text at the center\n",
    "        M=cv2.moments(cnt)\n",
    "        cx=int(M['m10']/M['m00'])\n",
    "        cy=int(M['m01']/M['m00'])\n",
    "        cv2.putText(image, shape_name, (cx-50, cy), cv2.FONT_HERSHEY_SIMPLEX,1,(0,0,0),1)\n",
    "        \n",
    "    elif len(approx)==4:\n",
    "        x,y,w,h = cv2.boundingRect(cnt)\n",
    "        M=cv2.moments(cnt)\n",
    "        cx=int(M['m10']/M['m00'])\n",
    "        cy=int(M['m01']/M['m00'])\n",
    "        \n",
    "        #check to see if 4-side polygon is square or rectangle\n",
    "        #cv2.boundingRect returns the top left and the width\n",
    "        if abs(w-h)<=3:\n",
    "            shape_name=\"Square\"\n",
    "            #find contour center to place text at the center\n",
    "            cv2.drawContours(image,[cnt],0,(0,125,255),-1)\n",
    "            cv2.putText(image, shape_name, (cx-50,cy), cv2.FONT_HERSHEY_SIMPLEX,1,(0,0,0),1)\n",
    "        else:\n",
    "            shape_name=\"Rectangle\"\n",
    "            #find contour center to place text at the center\n",
    "            cv2.drawContours(image,[cnt],0,(0,0,255),-1)\n",
    "            cv2.putText(image, shape_name, (cx-50,cy), cv2.FONT_HERSHEY_SIMPLEX,1,(0,0,0),1)\n",
    "            \n",
    "    elif len(approx)==10:\n",
    "        shape_name=\"Star\"\n",
    "        cv2.drawContours(image,[cnt],0,(255,255,0),-1)\n",
    "        M=cv2.moments(cnt)\n",
    "        cx=int(M['m10']/M['m00'])\n",
    "        cy=int(M['m01']/M['m00'])\n",
    "        cv2.putText(image, shape_name, (cx-50,cy), cv2.FONT_HERSHEY_SIMPLEX,1,(0,0,0),1)\n",
    "        \n",
    "    elif len(approx)>=15:\n",
    "        shape_name=\"Circle\"\n",
    "        cv2.drawContours(image,[cnt],0,(0,255,255),-1)\n",
    "        M=cv2.moments(cnt)\n",
    "        cx=int(M['m10']/M['m00'])\n",
    "        cy=int(M['m01']/M['m00'])\n",
    "        cv2.putText(image, shape_name, (cx-50,cy), cv2.FONT_HERSHEY_SIMPLEX,1,(0,0,0),1)\n",
    "        \n",
    "    \n",
    "    cv2.imshow(\"Indentifying shapes\",image)\n",
    "    cv2.waitKey()\n",
    "    \n",
    "cv2.destroyAllWindows()"
   ]
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