# OpenCV - Numpy Error **URL:** \ **Category:** Python\ **Tags:** numpy, raspberrypi, programming\ **Created:** [February 3, 2023, 9:17pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866 "2023-02-03T21:17:57Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Dev\_101](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/dev_101/32/6486_2.png) [@Dev\_101](https://forum.opencv.org/u/Dev_101)\ **Post date:** [February 3, 2023, 9:17pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/1 "2023-02-03T21:17:57Z")
Hello, I have been trying to plot a point on a frame in openCV. It is not working and I am getting this error: ````auto Traceback (most recent call last): File "/home/pi/Fair/Code/Software/Curve.py", line 84, in frame,mask,warp,warpThresh,roi,histogram,complete = getCurve(frame) File "/home/pi/Fair/Code/Software/Curve.py", line 48, in getCurve basePoint, histogram = getHistogram(warpThresh,display=True) File "/home/pi/Fair/Code/Software/Curve.py", line 26, in getHistogram cv2.line(img,x,img.shape[0],x,intensity//255,(255,0,255),1) cv2.error: OpenCV(4.5.3) :-1: error: (-5:Bad argument) in function 'line' > Overload resolution failed: > - Can't parse 'pt1'. Input argument doesn't provide sequence protocol > - Can't parse 'pt1'. Input argument doesn't provide sequence protocol``` ```` I am relatively new and a. basing my project on another tutorial, what did I do wrong? OS: Raspberrian 64 Bit Python:3.9.2 OpenCV: 4.5.3 ```auto #1/15/23 import cv2 import numpy as np import Thresh import ROI def empty(x): pass def getHistogram(img,minPer = 0.1,display = False): histValues = np.sum(img,axis=0) maxValue = np.max(histValues) minValue = minPer*maxValue indexArray = np.where(histValues>=minValue) basePoint = np.average(indexArray) basePoint = int(basePoint) print(basePoint) if display: imgHist = np.zeros((img.shape[0],img.shape[1],3),np.uint8) for x,intensity in enumerate(histValues): cv2.line(img,x,img.shape[0],x,intensity//255,(255,0,255),1) return basePoint,imgHist return basePoint def getCurve(frame): # Step 1: Threhold Paper frame,mask,result = Thresh.thresh(frame) frameWPoints = frame.copy() warpThresh = mask.copy() warpFrame = frame.copy() # Step 2: Define ROI hT, wT, c = frame.shape points = ROI.valTrackbars() # Step 3: Warp Image warpFrame = ROI.warpImg(warpFrame,points,wT,hT) warpThresh = ROI.warpImg(warpThresh,points,wT,hT) imgWarpPoints = ROI.drawPoints(frameWPoints,points) # Step 4: Apply Histogram - Summation of Pixels basePoint, histogram = getHistogram(warpThresh,display=True) # Step 5: Calculate Curve # Step 6: Filter Curve # Step 7: Display complete = frame return frame,mask,warpFrame,warpThresh,imgWarpPoints,histogram,complete if __name__ == " __main__": cv2.namedWindow("HSV") cv2.resizeWindow("HSV", 640, 240) cv2.createTrackbar("HUE Min", "HSV", 0, 255, empty) cv2.createTrackbar("HUE Max", "HSV", 179, 255, empty) cv2.createTrackbar("SAT Min", "HSV", 0, 255, empty) cv2.createTrackbar("SAT Max", "HSV", 255, 255, empty) cv2.createTrackbar("VALUE Min", "HSV", 113, 255, empty) cv2.createTrackbar("VALUE Max", "HSV", 255, 255, empty) intialTrackBarVals = [50, 108, 0, 140] ROI.initializeTrackbars(intialTrackBarVals) vid = cv2.VideoCapture(0) while(1): _,frame = vid.read() frame = cv2.resize(frame,(480,240)) frame,mask,warp,warpThresh,roi,histogram,complete = getCurve(frame) l1 =np.concatenate((frame,mask),axis=1) l2 =np.concatenate((roi,warp,warpThresh),axis=1) l3 =np.concatenate((histogram,complete),axis=1) cv2.imshow("THRESH",l1) cv2.imshow("TRANSFORM",l2) cv2.imshow("RESULT",l3) if cv2.waitKey(1) & 0xFF == ord('q'): break vid.release() cv2.destroyAllWindows() ``` ---
**Author:** ![berak](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@berak](https://forum.opencv.org/u/berak)\ **Post date:** [February 3, 2023, 9:20pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/2 "2023-02-03T21:20:28Z")
> [@Dev\_101](#): > > ```auto > cv2.line(img,x,img.shape[0],x,intensity//255,(255,0,255),1) > > ``` all coords must be integer, not float manually cast all 4 of them: `int(x)` , etc ---
**Author:** ![Dev\_101](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/dev_101/32/6486_2.png) [@Dev\_101](https://forum.opencv.org/u/Dev_101)\ **Post date:** [February 3, 2023, 9:27pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/3 "2023-02-03T21:27:04Z")
Hi, I tried that and it did not work. I might have converted the wrong arguments. May you show me which ones? Thanks, Dev\_101 ---
**Author:** ![berak](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@berak](https://forum.opencv.org/u/berak)\ **Post date:** [February 3, 2023, 9:50pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/4 "2023-02-03T21:50:55Z")
there’s always more than one error, right ? look here, you need 2 (x y) points (tuples) not 4 single integers [https://docs.opencv.org/4.x/d6/d6e/group\_\_imgproc\_\_draw.html#ga7078a9fae8c7e7d13d24dac2520ae4a2](https://docs.opencv.org/4.x/d6/d6e/group __imgproc__ draw.html#ga7078a9fae8c7e7d13d24dac2520ae4a2) ---
**Author:** ![Dev\_101](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/dev_101/32/6486_2.png) [@Dev\_101](https://forum.opencv.org/u/Dev_101)\ **Post date:** [February 3, 2023, 10:00pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/5 "2023-02-03T22:00:58Z")
Ok, that helped. Thank you so much. ---
**Author:** ![crackwitz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/crackwitz/32/14_2.png) [@crackwitz](https://forum.opencv.org/u/crackwitz)\ **Post date:** [February 3, 2023, 10:32pm UTC](https://forum.opencv.org/t/opencv-numpy-error/11866/6 "2023-02-03T22:32:04Z")
I would very much recommend that you learn how to use Python’s debugger. Learn this.