python - 未显示多条水平和垂直线
问题描述
在这里,我试图使用opencv,霍夫变换找到水的高度。该程序由精明边缘检测、背景减除、霍夫变换和高度估计组成。然后使用它绘制图形的高度。但这只会检测垂直线。未显示多条水平和垂直线。代码有问题吗?
from imutils.perspective import four_point_transform
from imutils import paths
import numpy as np
import imutils
import argparse
import cv2
import random
import math
import matplotlib.pyplot as plt
scaling_factorx = 0.8
scaling_factory = 0.8
cap = cv2.VideoCapture(0)
fgbg = cv2.createBackgroundSubtractorMOG2()
cap.set(3,640)
cap.set(4,480)
count = 0
height = []
while(1):
ret, frame = cap.read()
if frame is None:
break
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray, 1, 100)
lines = cv2.HoughLinesP(edges, rho = 1,theta = 2*np.pi/180,threshold = 10,minLineLength = 100,maxLineGap = 10);
if lines is not None:
for line in lines[0]:
dot1 = (line[0],line[1])
dot2 = (line[2],line[3])
cv2.line(frame, dot1, dot2, (255,0,0), 3)
length = line[1] - line[3]
print(length)
height.append(length)
cv2.imshow("output", frame)
frame = cv2.resize(frame, None, fx = scaling_factorx, fy = scaling_factory, interpolation = cv2.INTER_AREA)
fgmask = fgbg.apply(frame)
cv2.imshow('frame', fgmask)
gray_vid = cv2.cvtColor(frame, cv2.IMREAD_GRAYSCALE)
cv2.imshow('Original', frame)
edged_frame = cv2.Canny(frame, 1, 100)
cv2.imshow('Edges', edged_frame)
if cv2.waitKey(1) & 0xFF ==ord('q'):
break
x = []
y = []
for i in range(len(height)):
x.append(i)
y.append(height[i])
cap.release()
cv2.destroyAllWindows()
print(x,y)
plt.plot(x, y)
plt.xlabel('x - axis')
plt.ylabel('y - axis')
plt.title('Height')
plt.show()
解决方案
你只画一条线,因为你的 for 循环只在一条线上循环。
if lines is not None:
for line in lines: #for each line...not just one of them
for x1,y1,x2,y2 in line:
dot1 = (x1,y1)
dot2 = (x2,y2)
cv2.line(frame, dot1, dot2, (255,0,0), 3)
length = y1 - y2
print(length)
height.append(length)
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