How to mark the center and calculate the diameter of an image using opencv - python?
I am working on the recognition of the center and the image rendering. I'm using cv2.findContours to delimit the edges of the image of interest. And using cv.minEnclosingCircle (cnt) to circumnavigate my region of interest. The code below I can identify the center of each ROI, but I am not able to mark in the output of the image the circle corresponding to the image that I want to calculate and also I want to mark with a pqno point the exact location where the algorithm identified the center.
import cv2
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.offsetbox import AnchoredText
thresh = cv2.imread('IMD044.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
print (len(contours))
cnt = contours
for i in range (len(cnt)):
(x,y),radius = cv2.minEnclosingCircle(cnt[i])
center = (int(x),int(y))
radius = int(radius)
cv2.circle(thresh,center,radius,(0,255,0),2)
print ('Circle: ' + str(i) + ' - Center: ' + str(center) + ' - Radius: ' + str(radius))
plt.text(x-15, y+10, '+', fontsize=25, color = 'red')
plt.text(10, -10, 'Centro: '+str(center), fontsize=11, color = 'red')
plt.text(340, -10, 'Diametro: '+str((radius*2)/100)+'mm', fontsize=11, color = 'red')
plt.Circle(x, y, color='red', fill=False)
plt.imshow(thresh, cmap='gray')
plt.show()
I used the Opencv documentation to demarcate the contours and get the regions, but the green circle mark does not appear.
Exit:
Exit expected:
updating the question I was able to add the information, it's only necessary to add the circle and check if the diameter is correct.
python image opencv image-processing
asked Nov 13 at 18:32
Tecnologia da Net
929
add a comment |
I am working on the recognition of the center and the image rendering. I'm using cv2.findContours to delimit the edges of the image of interest. And using cv.minEnclosingCircle (cnt) to circumnavigate my region of interest. The code below I can identify the center of each ROI, but I am not able to mark in the output of the image the circle corresponding to the image that I want to calculate and also I want to mark with a pqno point the exact location where the algorithm identified the center.
import cv2
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.offsetbox import AnchoredText
thresh = cv2.imread('IMD044.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
print (len(contours))
cnt = contours
for i in range (len(cnt)):
(x,y),radius = cv2.minEnclosingCircle(cnt[i])
center = (int(x),int(y))
radius = int(radius)
cv2.circle(thresh,center,radius,(0,255,0),2)
print ('Circle: ' + str(i) + ' - Center: ' + str(center) + ' - Radius: ' + str(radius))
plt.text(x-15, y+10, '+', fontsize=25, color = 'red')
plt.text(10, -10, 'Centro: '+str(center), fontsize=11, color = 'red')
plt.text(340, -10, 'Diametro: '+str((radius*2)/100)+'mm', fontsize=11, color = 'red')
plt.Circle(x, y, color='red', fill=False)
plt.imshow(thresh, cmap='gray')
plt.show()
I used the Opencv documentation to demarcate the contours and get the regions, but the green circle mark does not appear.
Exit:
Exit expected:
updating the question I was able to add the information, it's only necessary to add the circle and check if the diameter is correct.
python image opencv image-processing
asked Nov 13 at 18:32
Tecnologia da Net
929
add a comment |
I am working on the recognition of the center and the image rendering. I'm using cv2.findContours to delimit the edges of the image of interest. And using cv.minEnclosingCircle (cnt) to circumnavigate my region of interest. The code below I can identify the center of each ROI, but I am not able to mark in the output of the image the circle corresponding to the image that I want to calculate and also I want to mark with a pqno point the exact location where the algorithm identified the center.
import cv2
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.offsetbox import AnchoredText
thresh = cv2.imread('IMD044.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
print (len(contours))
cnt = contours
for i in range (len(cnt)):
(x,y),radius = cv2.minEnclosingCircle(cnt[i])
center = (int(x),int(y))
radius = int(radius)
cv2.circle(thresh,center,radius,(0,255,0),2)
print ('Circle: ' + str(i) + ' - Center: ' + str(center) + ' - Radius: ' + str(radius))
plt.text(x-15, y+10, '+', fontsize=25, color = 'red')
plt.text(10, -10, 'Centro: '+str(center), fontsize=11, color = 'red')
plt.text(340, -10, 'Diametro: '+str((radius*2)/100)+'mm', fontsize=11, color = 'red')
plt.Circle(x, y, color='red', fill=False)
plt.imshow(thresh, cmap='gray')
plt.show()
I used the Opencv documentation to demarcate the contours and get the regions, but the green circle mark does not appear.
Exit:
Exit expected:
updating the question I was able to add the information, it's only necessary to add the circle and check if the diameter is correct.
python image opencv image-processing
asked Nov 13 at 18:32
Tecnologia da Net
929
I am working on the recognition of the center and the image rendering. I'm using cv2.findContours to delimit the edges of the image of interest. And using cv.minEnclosingCircle (cnt) to circumnavigate my region of interest. The code below I can identify the center of each ROI, but I am not able to mark in the output of the image the circle corresponding to the image that I want to calculate and also I want to mark with a pqno point the exact location where the algorithm identified the center.
import cv2
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.offsetbox import AnchoredText
thresh = cv2.imread('IMD044.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
print (len(contours))
cnt = contours
for i in range (len(cnt)):
(x,y),radius = cv2.minEnclosingCircle(cnt[i])
center = (int(x),int(y))
radius = int(radius)
cv2.circle(thresh,center,radius,(0,255,0),2)
print ('Circle: ' + str(i) + ' - Center: ' + str(center) + ' - Radius: ' + str(radius))
plt.text(x-15, y+10, '+', fontsize=25, color = 'red')
plt.text(10, -10, 'Centro: '+str(center), fontsize=11, color = 'red')
plt.text(340, -10, 'Diametro: '+str((radius*2)/100)+'mm', fontsize=11, color = 'red')
plt.Circle(x, y, color='red', fill=False)
plt.imshow(thresh, cmap='gray')
plt.show()
I used the Opencv documentation to demarcate the contours and get the regions, but the green circle mark does not appear.
Exit:
Exit expected:
updating the question I was able to add the information, it's only necessary to add the circle and check if the diameter is correct.
python image opencv image-processing
python image opencv image-processing
asked Nov 13 at 18:32
Tecnologia da Net
929
asked Nov 13 at 18:32
Tecnologia da Net
929
edited Nov 13 at 19:29
asked Nov 13 at 18:32
Tecnologia da Net
929
asked Nov 13 at 18:32
Tecnologia da Net
929
asked Nov 13 at 18:32
Tecnologia da Net
929
929
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
You are using a single channel image, but trying to show 3-channel color. Add the following:
...
thresh = cv2.imread('IMD016.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
thresh = cv2.cvtColor(thresh, cv2.COLOR_GRAY2RGB)
print (len(contours))
...
Also, be extra careful when mixing the OpenCV and PyPlot drawing routines. OpenCV uses BGR by default, while PyPlot uses RGB. Also, cv2 drawing routines don't add extra channels, while the plt does. Just need to keep that in mind
answered Nov 13 at 19:21
RafazZ
1,007624
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert tomm
– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know thedpiof the image.diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming1 dpi = 0.393701 pixel/cm
– RafazZ
Nov 13 at 21:31
|
show 4 more comments
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
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oldest
votes
active
oldest
votes
You are using a single channel image, but trying to show 3-channel color. Add the following:
...
thresh = cv2.imread('IMD016.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
thresh = cv2.cvtColor(thresh, cv2.COLOR_GRAY2RGB)
print (len(contours))
...
Also, be extra careful when mixing the OpenCV and PyPlot drawing routines. OpenCV uses BGR by default, while PyPlot uses RGB. Also, cv2 drawing routines don't add extra channels, while the plt does. Just need to keep that in mind
answered Nov 13 at 19:21
RafazZ
1,007624
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert tomm
– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know thedpiof the image.diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming1 dpi = 0.393701 pixel/cm
– RafazZ
Nov 13 at 21:31
|
show 4 more comments
You are using a single channel image, but trying to show 3-channel color. Add the following:
...
thresh = cv2.imread('IMD016.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
thresh = cv2.cvtColor(thresh, cv2.COLOR_GRAY2RGB)
print (len(contours))
...
Also, be extra careful when mixing the OpenCV and PyPlot drawing routines. OpenCV uses BGR by default, while PyPlot uses RGB. Also, cv2 drawing routines don't add extra channels, while the plt does. Just need to keep that in mind
answered Nov 13 at 19:21
RafazZ
1,007624
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert tomm
– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know thedpiof the image.diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming1 dpi = 0.393701 pixel/cm
– RafazZ
Nov 13 at 21:31
|
show 4 more comments
You are using a single channel image, but trying to show 3-channel color. Add the following:
...
thresh = cv2.imread('IMD016.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
thresh = cv2.cvtColor(thresh, cv2.COLOR_GRAY2RGB)
print (len(contours))
...
Also, be extra careful when mixing the OpenCV and PyPlot drawing routines. OpenCV uses BGR by default, while PyPlot uses RGB. Also, cv2 drawing routines don't add extra channels, while the plt does. Just need to keep that in mind
answered Nov 13 at 19:21
RafazZ
1,007624
You are using a single channel image, but trying to show 3-channel color. Add the following:
...
thresh = cv2.imread('IMD016.png',0)
_, contours,hierarchy = cv2.findContours(thresh,2,1)
thresh = cv2.cvtColor(thresh, cv2.COLOR_GRAY2RGB)
print (len(contours))
...
Also, be extra careful when mixing the OpenCV and PyPlot drawing routines. OpenCV uses BGR by default, while PyPlot uses RGB. Also, cv2 drawing routines don't add extra channels, while the plt does. Just need to keep that in mind
answered Nov 13 at 19:21
RafazZ
1,007624
edited Nov 13 at 19:39
answered Nov 13 at 19:21
RafazZ
1,007624
answered Nov 13 at 19:21
RafazZ
1,007624
answered Nov 13 at 19:21
RafazZ
1,007624
1,007624
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert tomm
– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know thedpiof the image.diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming1 dpi = 0.393701 pixel/cm
– RafazZ
Nov 13 at 21:31
|
show 4 more comments
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert tomm
– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know thedpiof the image.diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming1 dpi = 0.393701 pixel/cm
– RafazZ
Nov 13 at 21:31
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I saw that I updated the question. Is the above code correct to measure the diameter of the region of interest? yes, I just need to add the circle to the plot, I'm trying here
– Tecnologia da Net
Nov 13 at 19:30
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
I understand, I'm learning now to work with opencv. While to the diameter of the image, the code described above is correct? Can you help me about this?
– Tecnologia da Net
Nov 13 at 19:43
1
1
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert to
mm– RafazZ
Nov 13 at 19:45
I believe this is a diameter of the contour in terms of pixels. pixels don't automatically convert to
mm– RafazZ
Nov 13 at 19:45
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
hey guy, I discovered that my cv2.imshow is no longer displaying any output image, it happened after I updated the version of opencv to 4. What will happen? I already researched in several corners, and some people going through it, but no answer. Eh so, I can not get outputs in the algorithm above.
– Tecnologia da Net
Nov 13 at 21:29
If you want to convert the diameter to mm, you need to know the
dpi of the image. diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming 1 dpi = 0.393701 pixel/cm– RafazZ
Nov 13 at 21:31
If you want to convert the diameter to mm, you need to know the
dpi of the image. diameter_in_mm = dpi * 3.93701 * diameter_in_pixels. Of course, this is assuming 1 dpi = 0.393701 pixel/cm– RafazZ
Nov 13 at 21:31
|
show 4 more comments
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