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 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
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 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
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 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
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 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
asked Nov 13 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
edited Nov 13 '18 at 19:29
Tecnologia da Net
asked Nov 13 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
asked Nov 13 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
asked Nov 13 '18 at 18:32
Tecnologia da NetTecnologia da Net
979
979
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 '18 at 19:21
RafazZRafazZ
1,037624
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 '18 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 '18 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 '18 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 '18 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 '18 at 21:31
|
show 4 more comments
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
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 '18 at 19:21
RafazZRafazZ
1,037624
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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 at 19:21
RafazZRafazZ
1,037624
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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 at 19:21
RafazZRafazZ
1,037624
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 '18 at 19:21
RafazZRafazZ
1,037624
edited Nov 13 '18 at 19:39
answered Nov 13 '18 at 19:21
RafazZRafazZ
1,037624
answered Nov 13 '18 at 19:21
RafazZRafazZ
1,037624
answered Nov 13 '18 at 19:21
RafazZRafazZ
1,037624
1,037624
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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 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 '18 at 21:31
|
show 4 more comments
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