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pknowledge/opencv_python_object_detection.py

Created March 31, 2019 22:48
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OpenCV Python Tutorial For Beginners - Object Detection and Object Tracking Using HSV Color Space
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opencv_python_object_detection.py
import cv2
import numpy as np
def nothing(x):
pass
cv2.namedWindow("Tracking")
cv2.createTrackbar("LH", "Tracking", 0, 255, nothing)
cv2.createTrackbar("LS", "Tracking", 0, 255, nothing)
cv2.createTrackbar("LV", "Tracking", 0, 255, nothing)
cv2.createTrackbar("UH", "Tracking", 255, 255, nothing)
cv2.createTrackbar("US", "Tracking", 255, 255, nothing)
cv2.createTrackbar("UV", "Tracking", 255, 255, nothing)
while True:
frame = cv2.imread('smarties.png')
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
l_h = cv2.getTrackbarPos("LH", "Tracking")
l_s = cv2.getTrackbarPos("LS", "Tracking")
l_v = cv2.getTrackbarPos("LV", "Tracking")
u_h = cv2.getTrackbarPos("UH", "Tracking")
u_s = cv2.getTrackbarPos("US", "Tracking")
u_v = cv2.getTrackbarPos("UV", "Tracking")
l_b = np.array([l_h, l_s, l_v])
u_b = np.array([u_h, u_s, u_v])
mask = cv2.inRange(hsv, l_b, u_b)
res = cv2.bitwise_and(frame, frame, mask=mask)
cv2.imshow("frame", frame)
cv2.imshow("mask", mask)
cv2.imshow("res", res)
key = cv2.waitKey(1)
if key == 27:
break
cv2.destroyAllWindows()
Raw
opencv_python_object_detection_video.py
import cv2
import numpy as np
def nothing(x):
pass
cap = cv2.VideoCapture(0);
cv2.namedWindow("Tracking")
cv2.createTrackbar("LH", "Tracking", 0, 255, nothing)
cv2.createTrackbar("LS", "Tracking", 0, 255, nothing)
cv2.createTrackbar("LV", "Tracking", 0, 255, nothing)
cv2.createTrackbar("UH", "Tracking", 255, 255, nothing)
cv2.createTrackbar("US", "Tracking", 255, 255, nothing)
cv2.createTrackbar("UV", "Tracking", 255, 255, nothing)
while True:
#frame = cv2.imread('smarties.png')
_, frame = cap.read()
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
l_h = cv2.getTrackbarPos("LH", "Tracking")
l_s = cv2.getTrackbarPos("LS", "Tracking")
l_v = cv2.getTrackbarPos("LV", "Tracking")
u_h = cv2.getTrackbarPos("UH", "Tracking")
u_s = cv2.getTrackbarPos("US", "Tracking")
u_v = cv2.getTrackbarPos("UV", "Tracking")
l_b = np.array([l_h, l_s, l_v])
u_b = np.array([u_h, u_s, u_v])
mask = cv2.inRange(hsv, l_b, u_b)
res = cv2.bitwise_and(frame, frame, mask=mask)
cv2.imshow("frame", frame)
cv2.imshow("mask", mask)
cv2.imshow("res", res)
key = cv2.waitKey(1)
if key == 27:
break
cap.release()
cv2.destroyAllWindows()
@tekrajchhetri
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use cv2.imwrite()

@shrutishrestha
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why trackbar does not appear when we detect videos?

@JenilDave
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Is there a way to save the mask as a png file?
use:
cv2.imwrite('mask.png',mask)

@hissain
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hissain commented Jun 12, 2020

Getting error: (-215:Assertion failed) !empty() in function 'detectMultiScale'

@its-taufiq
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its-taufiq commented Jul 11, 2020 •
edited
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'I tried with the below code , just variable names has been changed , but this code is not working
I don't know what is going ..I tried to figure out the issue , but unable to fix..
can some one please help me with this ...I'll really appreciate ( please ignore the indentation because comment box is not considering the indentation )

import numpy as np
import cv2

cv2.namedWindow('Tracking')

creating tracking empty function

def empty(x):
pass

creating lower hsv paramters

cv2.createTrackbar('lower_H', 'Tracking', 0, 255, empty)
cv2.createTrackbar('lower_S', 'Tracking', 0, 255, empty)
cv2.createTrackbar('lower_V', 'Tracking', 0, 255, empty)

creating the upper hsv parameters

cv2.createTrackbar('upper_H', 'Tracking', 255, 255, empty)
cv2.createTrackbar('upper_S', 'Tracking', 255, 255, empty)
cv2.createTrackbar('upper_V', 'Tracking', 255, 255, empty)

while True:

frame = cv2.imread('smarties.png')

# converting the color of the image to HSV 
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

# getting the lower HSV limit 
lower_H = cv2.getTrackbarPos('lower_H', 'Tracking')
lower_S = cv2.getTrackbarPos('lower_S', 'Tracking')
lower_V = cv2.getTrackbarPos('lower_V', 'Tracking')

# getting the upper HSV limit 
upper_H = cv2.getTrackbarPos('upper_H', 'Tracking')
upper_S = cv2.getTrackbarPos('upper_S', 'Tracking')
upper_V = cv2.getTrackbarPos('lower_V', 'Tracking')

# setting up the lower blue_limit 
lower_blue = np.array([lower_H, lower_S, lower_V])

# setting up the upper blue_limit 
upper_blue = np.array([upper_H, upper_S, upper_V])

Mask = cv2.inRange(hsv, lower_blue, upper_blue)

# since we want only blue color , we will apply and operation 
result = cv2.bitwise_and(frame, frame, mask = Mask)

cv2.imshow('frame', frame)
cv2.imshow('mask', Mask)
cv2.imshow('result', result)

if cv2.waitKey(1) == 27:
    break

cv2.destroyAllWindows()

@surbhiagrawal22
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my code is not working ..have you got any solution @taufiq1001

'I tried with the below code , just variable names has been changed , but this code is not working
I don't know what is going ..I tried to figure out the issue , but unable to fix..
can some one please help me with this ...I'll really appreciate ( please ignore the indentation because comment box is not considering the indentation )

import numpy as np
import cv2

cv2.namedWindow('Tracking')

creating tracking empty function

def empty(x):
pass

creating lower hsv paramters

cv2.createTrackbar('lower_H', 'Tracking', 0, 255, empty)
cv2.createTrackbar('lower_S', 'Tracking', 0, 255, empty)
cv2.createTrackbar('lower_V', 'Tracking', 0, 255, empty)

creating the upper hsv parameters

cv2.createTrackbar('upper_H', 'Tracking', 255, 255, empty)
cv2.createTrackbar('upper_S', 'Tracking', 255, 255, empty)
cv2.createTrackbar('upper_V', 'Tracking', 255, 255, empty)

while True:

frame = cv2.imread('smarties.png')

# converting the color of the image to HSV 
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

# getting the lower HSV limit 
lower_H = cv2.getTrackbarPos('lower_H', 'Tracking')
lower_S = cv2.getTrackbarPos('lower_S', 'Tracking')
lower_V = cv2.getTrackbarPos('lower_V', 'Tracking')

# getting the upper HSV limit 
upper_H = cv2.getTrackbarPos('upper_H', 'Tracking')
upper_S = cv2.getTrackbarPos('upper_S', 'Tracking')
upper_V = cv2.getTrackbarPos('lower_V', 'Tracking')

# setting up the lower blue_limit 
lower_blue = np.array([lower_H, lower_S, lower_V])

# setting up the upper blue_limit 
upper_blue = np.array([upper_H, upper_S, upper_V])

Mask = cv2.inRange(hsv, lower_blue, upper_blue)

# since we want only blue color , we will apply and operation 
result = cv2.bitwise_and(frame, frame, mask = Mask)

cv2.imshow('frame', frame)
cv2.imshow('mask', Mask)
cv2.imshow('result', result)

if cv2.waitKey(1) == 27:
    break

cv2.destroyAllWindows()

Hey,, i am also writing the same code,, but my code is also not working ..have u got the solution?
please let me know

@KorraHaswi
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why is source1 and source2 same as frame in line 33 when creating the mask? also why does mask need an hsv image. why cant i use the same colored image in bgr format? anyone can tell?

@Kennerdol
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Kennerdol commented Jul 18, 2021 •
edited
Loading

@pknowledge i did copy and paste of your code but its not working just like mine is not working
Here is my code:
`import cv2 as cv
import numpy as np

def nothing(x):
pass

cv.namedWindow('Tracking')
cv.createTrackbar('Lower_Hue', 'Tracking', 0, 255, nothing)
cv.createTrackbar('Lower_Saturation', 'Tracking', 0, 255, nothing)
cv.createTrackbar('Lower_Value', 'Tracking', 0, 255, nothing)
cv.createTrackbar('Upper_Hue', 'Tracking', 255, 255, nothing)
cv.createTrackbar('Upper_Saturation', 'Tracking', 255, 255, nothing)
cv.createTrackbar('Upper_Value', 'Tracking', 255, 255, nothing)

while True:
img = cv.imread('opencv_resources/balls.jpeg')
hsv = cv.cvtColor(img, cv.cv2.COLOR_BGR2HSV)

L_Hue = cv.getTrackbarPos('Lower_Hue', 'Tracking')
L_Saturation = cv.getTrackbarPos('Lower_Saturation', 'Tracking')
L_Value = cv.getTrackbarPos('Lower_Value', 'Tracking')

U_Hue = cv.getTrackbarPos('Upper_Hue', 'Tracking')
U_Saturation = cv.getTrackbarPos('Upper_Saturation', 'Tracking')
U_Value = cv.getTrackbarPos('Upper_Value', 'Tracking')

lower_bound = np.array([L_Hue, L_Saturation, L_Value])
upper_bound = np.array([U_Hue, U_Saturation, U_Value])

mask = cv.inRange(hsv, lower_bound, upper_bound)
result = cv.bitwise_and(img, img, mask=mask)

cv.imshow('Original', img)
cv.imshow('MASK', mask)
cv.imshow('RESULT', result)

key = cv.waitKey(0) & 0xff
if key == 27:
    break

cv.destroyAllWindows()
ob_tra

`

`

@rawstar134
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To detect the object from the image from scratch using python; Click here I found the best article https://debuggingsolution.blogspot.com/2022/02/object-detection-from-scratch-in-python.html

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