# SyntaxError: invalid syntax ---\>frame = cv2.circle(frame, (int(a), int(b)), 5, color\[i\].tolist(), -1)

**URL:** <https://forum.opencv.org/t/syntaxerror-invalid-syntax-frame-cv2-circle-frame-int-a-int-b-5-color-i-tolist-1/9112>\
**Category:** Python\
**Tags:** programming\
**Created:** [June 10, 2022, 4:37pm UTC](https://forum.opencv.org/t/syntaxerror-invalid-syntax-frame-cv2-circle-frame-int-a-int-b-5-color-i-tolist-1/9112 "2022-06-10T16:37:34Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Steve\_Shaw](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@Steve\_Shaw](https://forum.opencv.org/u/Steve_Shaw)\
**Post date:** [June 10, 2022, 4:37pm UTC](https://forum.opencv.org/t/syntaxerror-invalid-syntax-frame-cv2-circle-frame-int-a-int-b-5-color-i-tolist-1/9112/1 "2022-06-10T16:37:34Z")

</div>

Hello guys,  
When I tried to use Lucas-Kanade on optical flow, I couldn’t figure out why there’s always invalid syntax when I use

```
frame = cv2.circle(frame, (int(a), int(b)), 5, color[i].tolist(), -1)

```

```auto
frame = cv2.circle(frame, (int(a), int(b)), 5, color[i].tolist(), -1)
    ^
SyntaxError: invalid syntax

```

Here’s the code, guys please help me. Thanks a lot!!!

```auto
import numpy as np
import cv2

cap = cv2.VideoCapture('02_Video/02_Foreground.avi')
feature_params = dict( maxCorners = 100,
qualityLevel = 0.3,
minDistance = 7 )

lk_params = dict( winSize = (15,15), maxLevel = 2 )

color = np.random.randint(0,255,(100,3))

ret, old_frame = cap.read()
old_gray = cv2.cvtColor(old_frame, cv2.COLOR_BGR2GRAY)
p0 = cv2.goodFeaturesToTrack(old_gray, mask = None, **feature_params)
mask = np.zeros_like(old_frame)

while(True):
ret,frame = cap.read()
frame_gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
p1, st, err = cv2.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None, **lk_params)                         

good_new = p1[st==1]  
good_old = p0[st==1]

for i, (new,old) in enumerate(zip(good_new,good_old)):
    a,b = new.ravel()
    c,d = old.ravel()
    mask = cv2.line(mask,(int(a),int(b),(int(c),int(d)),color[i].tolist(),2)                         
    frame = cv2.circle(frame, (int(a), int(b)), 5, color[i].tolist(), -1) #<-------The problem is here!!!!!!!!!!!!!
    #image = cv2.circle(image, center_coordinates, radius, color, thickness)
img = cv2.add(frame,mask)

cv2.imshow('frame',img)
k = cv2.waitKey(150) & 0xff
if k == 27:
    break
    
old_gray = frame_gray.copy()
p0 = good_new.reshape(-1,1,2)

cv2.destroyAllWindows()
cap.release()

```

---

<div class="post-metadata">

**Author:** ![berak](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@berak](https://forum.opencv.org/u/berak)\
**Post date:** [June 10, 2022, 5:30pm UTC](https://forum.opencv.org/t/syntaxerror-invalid-syntax-frame-cv2-circle-frame-int-a-int-b-5-color-i-tolist-1/9112/2 "2022-06-10T17:30:49Z")

</div>

hey, that’s [already solved](https://github.com/opencv/opencv/issues/22085#issuecomment-1152273159), no ?

```auto
mask = cv2.line(mask,(int(a),int(b),(int(c),int(d)),color[i].tolist(),2)                                       

```

closing `)` bracket missing after `int(b)`

---

<div class="post-metadata">

**Author:** ![Steve\_Shaw](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@Steve\_Shaw](https://forum.opencv.org/u/Steve_Shaw)\
**Post date:** [June 11, 2022, 3:10pm UTC](https://forum.opencv.org/t/syntaxerror-invalid-syntax-frame-cv2-circle-frame-int-a-int-b-5-color-i-tolist-1/9112/3 "2022-06-11T15:10:11Z")

</div>

> [@berak](#):
>
> osing `)` bracket missing after `int(b)`

Nice work，bro！I worked it out!!!