OpenCv Get edge distance to circle center - opencv

Question

A bit off an intro, i need to make a visual aid to align sheets against fixed points.
My setup has 3 points, a sheetmetal plate needs to be positioned against these points using a forklift.
Its a gentle task, we cant use brut force to align the sheet, so i want to install camera's to help them align there sheetmetal plate.
Code so far:
import sys
import cv2 as cv
import numpy as np
cap = cv.VideoCapture(0)
val = 50
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
gray = cv.GaussianBlur(gray, (5,5), 0)
rows = gray.shape[0]
circles = cv.HoughCircles(gray, cv.HOUGH_GRADIENT, 1, rows / 8,
param1=100, param2=30,
minRadius=1, maxRadius=30)
edges = cv.Canny(gray,val,val*3,apertureSize = 3)
lines = cv.HoughLines(edges,1.2,np.pi/180,200)
font = cv.FONT_HERSHEY_SIMPLEX
color = (255, 255, 255)
thickness = 2
index = 1
if len(circles[0]) > 2 :
circles = np.uint16(np.floor(circles))
circles2=sorted(circles[0],key=lambda x:x[0],reverse=False)
print (circles2)
for i in circles2:
center = (i[0], i[1])
cv.circle(frame, center, 1, (0, 255, 0), 3)
text = str(index) +' ' + str(i[0]) +' ' + str(i[1])
cv.putText(frame, text, center, font, 1, color, thickness, cv.LINE_AA)
index += 1
cv.imshow("detected circles", frame)
cv.imshow("detected edges", edges)
if cv.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv.destroyAllWindows()
So the points are found, somehow i need to find the first 255 value in edges right 'above' the 2nd and 3th point, and the last 255 value next to the first point
i'm struggling too slice? the array, find the value 255, returns its index, so i can calculate the distance between point and plate.
any ideas on how to get the distance between?
Thank you in advance

Answer 1

I got it.
the code:
import sys
import cv2 as cv
import numpy as np
cap = cv.VideoCapture(0)
val = 50
singleprint = 0
# Dots per millimeter
dpmm = 2
def distance(circle):
# Calculating the distance np.where(array[row, column])
p = 0
if axis == 1:
p = np.where(edges[:,circle[0]] == 255)[0][0]
return (circle[1] - p - circle[2])/dpmm
else:
p = np.where(edges[circle[1],:] == 255)[0][-1]
return (p - circle[0] - circle[2])/dpmm
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
gray = cv.GaussianBlur(gray, (5,5), 0)
rows = gray.shape[0]
circles = cv.HoughCircles(gray, cv.HOUGH_GRADIENT, 1, rows / 8,
param1=100, param2=30,
minRadius=1, maxRadius=30)
edges = cv.Canny(gray,val,val*3,apertureSize = 3)
lines = cv.HoughLines(edges,1.2,np.pi/180,200)
# Text property's
font = cv.FONT_HERSHEY_SIMPLEX
color = (255, 255, 255)
thickness = 2
index = 1
axis = 0
if len(circles[0]) > 2 :
circles = np.uint16(np.floor(circles))
circles2=sorted(circles[0],key=lambda x:x[0],reverse=False)
for i in circles2:
center = (i[0], i[1])
cv.circle(frame, center, 1, (0, 255, 0), 3)
text = str(distance(i))
cv.putText(frame, text, center, font, 1, color, thickness, cv.LINE_AA)
index += 1
axis = 1
cv.imshow("detected circles", frame)
if cv.waitKey(1) & 0xFF == ord('q'):
break
# When everything done, release the capture
cap.release()
cv.destroyAllWindows()
Key was learning to use Numpy in a specific row or column
np.where(edges[:,circle[0]] == 255)[0][0]
resource: https://youtu.be/GB9ByFAIAH4?t=1103
Hope this helps others.
Thanks all