How matplotlib.pyplot.imshow deal with over 255 pixel value magically? [duplicate]
This question already has an answer here:
matplotlib imshow - default colour normalisation
1 answer
Matplotlib : What is the function of cmap in imshow?
1 answer
Recently I've been working with matplotlib to deal with image.
And I found one thing interesting is that "matplotlib.pyplot.imshow" seems to work
the issue out magically that if you have pixel value more than 255 which in opencv with function
imshow would completely be mess up the image
Here's what I try：
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt
img=cv.imread("image1.jpg",cv.IMREAD_GRAYSCALE)
img
array([[ 69, 69, 68, ..., 191, 184, 180],
[ 65, 65, 65, ..., 197, 191, 188],
[ 61, 61, 62, ..., 200, 197, 195],
...,
[ 75, 73, 73, ..., 96, 88, 65],
[ 84, 80, 76, ..., 145, 135, 111],
[ 90, 82, 73, ..., 216, 215, 217]], dtype=uint8)
img=img.astype(np.int32)
img+=500
plt.imshow(img, cmap="gray")
plt.show()
>>>img
array([[567, 567, 566, ..., 689, 682, 678],
[563, 563, 563, ..., 695, 689, 686],
[559, 559, 560, ..., 698, 695, 693],
...,
[573, 571, 571, ..., 594, 586, 563],
[582, 578, 574, ..., 643, 633, 609],
[588, 580, 571, ..., 714, 713, 715]], dtype=int32)
At the end ,you can find out that the array actually is not changed
but it gives the perfectly original image
I wonder how they deal with this problem,Thanks in advance!
python opencv matplotlib overflow
asked Nov 15 '18 at 11:44
kriskris
345
marked as duplicate by Matthieu Brucher, ImportanceOfBeingErnest matplotlib
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Nov 15 '18 at 14:34
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
This question already has an answer here:
matplotlib imshow - default colour normalisation
1 answer
Matplotlib : What is the function of cmap in imshow?
1 answer
Recently I've been working with matplotlib to deal with image.
And I found one thing interesting is that "matplotlib.pyplot.imshow" seems to work
the issue out magically that if you have pixel value more than 255 which in opencv with function
imshow would completely be mess up the image
Here's what I try：
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt
img=cv.imread("image1.jpg",cv.IMREAD_GRAYSCALE)
img
array([[ 69, 69, 68, ..., 191, 184, 180],
[ 65, 65, 65, ..., 197, 191, 188],
[ 61, 61, 62, ..., 200, 197, 195],
...,
[ 75, 73, 73, ..., 96, 88, 65],
[ 84, 80, 76, ..., 145, 135, 111],
[ 90, 82, 73, ..., 216, 215, 217]], dtype=uint8)
img=img.astype(np.int32)
img+=500
plt.imshow(img, cmap="gray")
plt.show()
>>>img
array([[567, 567, 566, ..., 689, 682, 678],
[563, 563, 563, ..., 695, 689, 686],
[559, 559, 560, ..., 698, 695, 693],
...,
[573, 571, 571, ..., 594, 586, 563],
[582, 578, 574, ..., 643, 633, 609],
[588, 580, 571, ..., 714, 713, 715]], dtype=int32)
At the end ,you can find out that the array actually is not changed
but it gives the perfectly original image
I wonder how they deal with this problem,Thanks in advance!
python opencv matplotlib overflow
asked Nov 15 '18 at 11:44
kriskris
345
marked as duplicate by Matthieu Brucher, ImportanceOfBeingErnest matplotlib
Users with the matplotlib badge can single-handedly close matplotlib questions as duplicates and reopen them as needed.
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Nov 15 '18 at 14:34
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
This question already has an answer here:
matplotlib imshow - default colour normalisation
1 answer
Matplotlib : What is the function of cmap in imshow?
1 answer
Recently I've been working with matplotlib to deal with image.
And I found one thing interesting is that "matplotlib.pyplot.imshow" seems to work
the issue out magically that if you have pixel value more than 255 which in opencv with function
imshow would completely be mess up the image
Here's what I try：
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt
img=cv.imread("image1.jpg",cv.IMREAD_GRAYSCALE)
img
array([[ 69, 69, 68, ..., 191, 184, 180],
[ 65, 65, 65, ..., 197, 191, 188],
[ 61, 61, 62, ..., 200, 197, 195],
...,
[ 75, 73, 73, ..., 96, 88, 65],
[ 84, 80, 76, ..., 145, 135, 111],
[ 90, 82, 73, ..., 216, 215, 217]], dtype=uint8)
img=img.astype(np.int32)
img+=500
plt.imshow(img, cmap="gray")
plt.show()
>>>img
array([[567, 567, 566, ..., 689, 682, 678],
[563, 563, 563, ..., 695, 689, 686],
[559, 559, 560, ..., 698, 695, 693],
...,
[573, 571, 571, ..., 594, 586, 563],
[582, 578, 574, ..., 643, 633, 609],
[588, 580, 571, ..., 714, 713, 715]], dtype=int32)
At the end ,you can find out that the array actually is not changed
but it gives the perfectly original image
I wonder how they deal with this problem,Thanks in advance!
python opencv matplotlib overflow
asked Nov 15 '18 at 11:44
kriskris
345
This question already has an answer here:
matplotlib imshow - default colour normalisation
1 answer
Matplotlib : What is the function of cmap in imshow?
1 answer
Recently I've been working with matplotlib to deal with image.
And I found one thing interesting is that "matplotlib.pyplot.imshow" seems to work
the issue out magically that if you have pixel value more than 255 which in opencv with function
imshow would completely be mess up the image
Here's what I try：
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt
img=cv.imread("image1.jpg",cv.IMREAD_GRAYSCALE)
img
array([[ 69, 69, 68, ..., 191, 184, 180],
[ 65, 65, 65, ..., 197, 191, 188],
[ 61, 61, 62, ..., 200, 197, 195],
...,
[ 75, 73, 73, ..., 96, 88, 65],
[ 84, 80, 76, ..., 145, 135, 111],
[ 90, 82, 73, ..., 216, 215, 217]], dtype=uint8)
img=img.astype(np.int32)
img+=500
plt.imshow(img, cmap="gray")
plt.show()
>>>img
array([[567, 567, 566, ..., 689, 682, 678],
[563, 563, 563, ..., 695, 689, 686],
[559, 559, 560, ..., 698, 695, 693],
...,
[573, 571, 571, ..., 594, 586, 563],
[582, 578, 574, ..., 643, 633, 609],
[588, 580, 571, ..., 714, 713, 715]], dtype=int32)
At the end ,you can find out that the array actually is not changed
but it gives the perfectly original image
I wonder how they deal with this problem,Thanks in advance!
This question already has an answer here:
matplotlib imshow - default colour normalisation
1 answer
Matplotlib : What is the function of cmap in imshow?
1 answer
python opencv matplotlib overflow
python opencv matplotlib overflow
asked Nov 15 '18 at 11:44
kriskris
345
asked Nov 15 '18 at 11:44
kriskris
345
asked Nov 15 '18 at 11:44
kriskris
345
asked Nov 15 '18 at 11:44
kriskris
345
asked Nov 15 '18 at 11:44
kriskris
345
345
marked as duplicate by Matthieu Brucher, ImportanceOfBeingErnest matplotlib
Users with the matplotlib badge can single-handedly close matplotlib questions as duplicates and reopen them as needed.
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Nov 15 '18 at 14:34
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
marked as duplicate by Matthieu Brucher, ImportanceOfBeingErnest matplotlib
Users with the matplotlib badge can single-handedly close matplotlib questions as duplicates and reopen them as needed.
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Nov 15 '18 at 14:34
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
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