如何为用户提供输入以检测opencv视频中的特定颜色?

Question

我用python编写了一段代码来检测OpenCV中的红色。我得到了正确的输出，但我想在代码中为用户提供输入以检测特定颜色。例如：如果我将蓝色作为用户输入，它应该在输出上只显示蓝色。我还想添加一些属性作为输出，例如检测到该对象的时间和实时视频的位置。我是python和opencv的新手，如果我能得到一些指导，那就太好了。

我现有的代码如下：

import cv2
import numpy as np
# Capture the input frame from webcam
def get_frame(cap, scaling_factor):
# Capture the frame from video capture object
ret, frame = cap.read()
# Resize the input frame
frame = cv2.resize(frame, None, fx=scaling_factor,
fy=scaling_factor, interpolation=cv2.INTER_AREA)
return frame
if __name__=='__main__':
cap = cv2.VideoCapture(0)
scaling_factor = 0.5
# Iterate until the user presses ESC key
while True:
frame = get_frame(cap, scaling_factor)
# Convert the HSV colorspace
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
# Define 'blue' range in HSV colorspace
lower = np.array([60,100,100])
upper = np.array([180,255,255])
# Threshold the HSV image to get only blue color
mask = cv2.inRange(hsv, lower, upper)
# Bitwise-AND mask and original image
res = cv2.bitwise_and(frame, frame, mask=mask)
res = cv2.medianBlur(res, 5)
cv2.imshow('Original image', frame)
cv2.imshow('Color Detector', res)
# Check if the user pressed ESC key
c = cv2.waitKey(5)
if c == 27:
break
cv2.destroyAllWindows()   

Answer 1

您的代码似乎工作正常。查看有关从 RGB 转换为 HSV 的方程式，请记住 OpenCV 中的边界在 0-180 之间(H通道(和 0-255 (S和V通道(之间，我们可以概括代码以适用于所有颜色。

import cv2
import numpy as np
# Capture the input frame from webcam
def get_frame(cap, scaling_factor):
# Capture the frame from video capture object
ret, frame = cap.read()
# Resize the input frame
frame = cv2.resize(frame, None, fx=scaling_factor,
fy=scaling_factor, interpolation=cv2.INTER_AREA)
return frame
# Define the color range in HSV colorspace
lower1 = np.array([0,100,100])
upper1 = np.array([60,255,255])
lower2 = np.array([120,100,100])
upper2 = np.array([180,255,255])
def color_range(degree):
# Degree is between 0-360
# OpenCV uses 0-180 range for H channel
degree = int(degree/2);
global lower1, upper1, lower2, upper2
if degree < 60:
lower1 = np.array([int(0),100,100])
upper1 = np.array([degree+60,255,255])
lower2 = np.array([degree+120,100,100])
upper2 = np.array([int(180),255,255])
elif degree > 120:
lower1 = np.array([degree-60,100,100])
upper1 = np.array([int(180),255,255])
lower2 = np.array([int(0),100,100])
upper2 = np.array([degree-120,255,255])
else:
lower1 = np.array([degree-60,100,100])
upper1 = np.array([degree+60,255,255])
# ineffective variables
lower2 = np.array([181,100,100])
upper2 = np.array([181,255,255])
if __name__=='__main__':
cap = cv2.VideoCapture(0)
scaling_factor = 0.5
# create trackbar for color change
winname = 'Color Detector'
cv2.namedWindow(winname)
cv2.createTrackbar('Color', winname, 0, 360, color_range)
# Iterate until the user presses ESC key
while True:
frame = get_frame(cap, scaling_factor)
# Convert the HSV colorspace
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
# Threshold the HSV image to get only desired color
mask1 = cv2.inRange(hsv, lower1, upper1)
mask2 = cv2.inRange(hsv, lower2, upper2)
mask = cv2.bitwise_or(mask1, mask2)
# Bitwise-AND mask and original image
res = cv2.bitwise_and(frame, frame, mask=mask)
cv2.imshow('Original image', frame)
cv2.imshow(winname, res)
# Check if the user pressed ESC key
c = cv2.waitKey(1) & 0xFF
if c == 27:
break
cv2.destroyAllWindows()
cap.release()