python - How to detect the end of a crop row with opencv?

Question

I am writing a program to detect crop rows in uav imagery and I have successfully managed to detect crop rows in cropped sections of the image using opencv and python, however the issue I am running into now is how to go about detecting the end of a crop row.

The image is of a field(Cant share it publicly) and I am attempting to detect all the rows in that field, I can detect the rows however currently I am simply draw the line along the row from the top to bottom of the image. Instead I would like draw this line from the start to end of the crop row.

i.e. smething like this https://i.stack.imgur.com/WUkg6.jpg (Not enough rep to post images yet) But essentially I need to detect the end of the row so I can draw the line to the just the end of the row.

Any Ideas on how this might be done?

Answer 1

Use the Probabilistic Hough Line Transform:

import cv2
import numpy as np

cap = cv2.VideoCapture(0)

frame = cv2.imread("crop.jpg")
# It converts the BGR color space of image to HSV color space
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

# Threshold of blue in HSV space
lower_green = np.array([21, 115, 0])
upper_green = np.array([179, 255, 255])

# preparing the mask to overlay
mask = cv2.inRange(hsv, lower_green, upper_green)

mask = cv2.blur(mask, (5,5))
ret, mask = cv2.threshold(mask, 128, 255, cv2.THRESH_BINARY)

edges = cv2.Canny(mask,100,200)

# The black region in the mask has the value of 0,
# so when multiplied with original image removes all non-blue regions
result = cv2.bitwise_and(frame, frame, mask = mask)

cdst = cv2.cvtColor(mask, cv2.COLOR_GRAY2BGR)
linesP = cv2.HoughLinesP(edges, 1, np.pi / 180, 50, None, 100, 30)

if linesP is not None:
    for i in range(0, len(linesP)):
        l = linesP[i][0]
        cv2.line(cdst, (l[0], l[1]), (l[2], l[3]), (0,0,255), 3, cv2.LINE_AA)

cv2.imshow("Detected Lines (in red) - Probabilistic Line Transform", cdst)
cv2.imshow('frame', frame)
cv2.imshow('mask', mask)
cv2.imshow('result', result)

cv2.waitKey(-1)