How should I convert a float32 image to an uint8 image?

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0
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I want to convert a float32 image into uint8 image in Python using the openCV library. I used the following code, but I do not know whether it is correct or not.

Here I is the float32 image.

J = I*255
J = J.astype(np.uint8)

I really appreciate if can you help me.

edited Nov 10 at 7:54

Greenonline

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asked Nov 10 at 2:56

Hamidreza

145

Since no one explicitly said it, so long as your values are between 0 and 1 in your float image, then yes, your code is correct.
– Alexander Reynolds
Nov 10 at 5:30

add a comment |

up vote
0
down vote

favorite

I want to convert a float32 image into uint8 image in Python using the openCV library. I used the following code, but I do not know whether it is correct or not.

Here I is the float32 image.

J = I*255
J = J.astype(np.uint8)

I really appreciate if can you help me.

edited Nov 10 at 7:54

Greenonline

97121424

asked Nov 10 at 2:56

Hamidreza

145

Since no one explicitly said it, so long as your values are between 0 and 1 in your float image, then yes, your code is correct.
– Alexander Reynolds
Nov 10 at 5:30

add a comment |

up vote
0
down vote

favorite

I want to convert a float32 image into uint8 image in Python using the openCV library. I used the following code, but I do not know whether it is correct or not.

Here I is the float32 image.

J = I*255
J = J.astype(np.uint8)

I really appreciate if can you help me.

edited Nov 10 at 7:54

Greenonline

97121424

asked Nov 10 at 2:56

Hamidreza

145

I want to convert a float32 image into uint8 image in Python using the openCV library. I used the following code, but I do not know whether it is correct or not.

Here I is the float32 image.

J = I*255
J = J.astype(np.uint8)

I really appreciate if can you help me.

python opencv image-processing

edited Nov 10 at 7:54

Greenonline

97121424

asked Nov 10 at 2:56

Hamidreza

145

edited Nov 10 at 7:54

Greenonline

97121424

asked Nov 10 at 2:56

Hamidreza

145

edited Nov 10 at 7:54

Greenonline

97121424

edited Nov 10 at 7:54

Greenonline

97121424

edited Nov 10 at 7:54

Greenonline

97121424

asked Nov 10 at 2:56

Hamidreza

145

asked Nov 10 at 2:56

Hamidreza

145

asked Nov 10 at 2:56

Hamidreza

145

Since no one explicitly said it, so long as your values are between 0 and 1 in your float image, then yes, your code is correct.
– Alexander Reynolds
Nov 10 at 5:30

add a comment |

Since no one explicitly said it, so long as your values are between 0 and 1 in your float image, then yes, your code is correct.
– Alexander Reynolds
Nov 10 at 5:30

Since no one explicitly said it, so long as your values are between 0 and 1 in your float image, then yes, your code is correct.
– Alexander Reynolds
Nov 10 at 5:30

add a comment |

1 Answer
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up vote
0
down vote

If you to convert your image from float32 to uint8 numpy and opencv in python offers two convenient approaches.

If you know that your image have a range between 0 and 255 or between 0 and 1 then you can simply make the convertion the way you already do:

I *= 255 # or any coefficient
I = I.astype(np.uint8)

If you don't know the range I suggest you to apply a min max normalization
i.e. : (value - min) / (max - min)

opencv have that already implemented:

I = cv2.normalize(I,None,0,255,cv2.NORM_MINMAX,cv2.CV_8U)

The returned I will already have the type np.uint8 and a range between 0 and 255

Using numpy you can also write something similar:

def norm8(I):
 mn = I.min()
 mx = I.max()

 mx -= mn

 I = (I - mn)/mx
 return I.astype(np.uint8)

answered Nov 10 at 5:19

John_Sharp1318

399311

add a comment |

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1 Answer
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1 Answer
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active

oldest

votes

up vote
0
down vote

If you to convert your image from float32 to uint8 numpy and opencv in python offers two convenient approaches.

If you know that your image have a range between 0 and 255 or between 0 and 1 then you can simply make the convertion the way you already do:

I *= 255 # or any coefficient
I = I.astype(np.uint8)

If you don't know the range I suggest you to apply a min max normalization
i.e. : (value - min) / (max - min)

opencv have that already implemented:

I = cv2.normalize(I,None,0,255,cv2.NORM_MINMAX,cv2.CV_8U)

The returned I will already have the type np.uint8 and a range between 0 and 255

Using numpy you can also write something similar:

def norm8(I):
 mn = I.min()
 mx = I.max()

 mx -= mn

 I = (I - mn)/mx
 return I.astype(np.uint8)

answered Nov 10 at 5:19

John_Sharp1318

399311

add a comment |

up vote
0
down vote

If you to convert your image from float32 to uint8 numpy and opencv in python offers two convenient approaches.

If you know that your image have a range between 0 and 255 or between 0 and 1 then you can simply make the convertion the way you already do:

I *= 255 # or any coefficient
I = I.astype(np.uint8)

If you don't know the range I suggest you to apply a min max normalization
i.e. : (value - min) / (max - min)

opencv have that already implemented:

I = cv2.normalize(I,None,0,255,cv2.NORM_MINMAX,cv2.CV_8U)

The returned I will already have the type np.uint8 and a range between 0 and 255

Using numpy you can also write something similar:

def norm8(I):
 mn = I.min()
 mx = I.max()

 mx -= mn

 I = (I - mn)/mx
 return I.astype(np.uint8)

answered Nov 10 at 5:19

John_Sharp1318

399311

add a comment |

up vote
0
down vote

If you to convert your image from float32 to uint8 numpy and opencv in python offers two convenient approaches.

If you know that your image have a range between 0 and 255 or between 0 and 1 then you can simply make the convertion the way you already do:

I *= 255 # or any coefficient
I = I.astype(np.uint8)

If you don't know the range I suggest you to apply a min max normalization
i.e. : (value - min) / (max - min)

opencv have that already implemented:

I = cv2.normalize(I,None,0,255,cv2.NORM_MINMAX,cv2.CV_8U)

The returned I will already have the type np.uint8 and a range between 0 and 255

Using numpy you can also write something similar:

def norm8(I):
 mn = I.min()
 mx = I.max()

 mx -= mn

 I = (I - mn)/mx
 return I.astype(np.uint8)

answered Nov 10 at 5:19

John_Sharp1318

399311

If you to convert your image from float32 to uint8 numpy and opencv in python offers two convenient approaches.

If you know that your image have a range between 0 and 255 or between 0 and 1 then you can simply make the convertion the way you already do:

I *= 255 # or any coefficient
I = I.astype(np.uint8)

If you don't know the range I suggest you to apply a min max normalization
i.e. : (value - min) / (max - min)

opencv have that already implemented:

I = cv2.normalize(I,None,0,255,cv2.NORM_MINMAX,cv2.CV_8U)

The returned I will already have the type np.uint8 and a range between 0 and 255

Using numpy you can also write something similar:

def norm8(I):
 mn = I.min()
 mx = I.max()

 mx -= mn

 I = (I - mn)/mx
 return I.astype(np.uint8)

answered Nov 10 at 5:19

John_Sharp1318

399311

answered Nov 10 at 5:19

John_Sharp1318

399311

answered Nov 10 at 5:19

John_Sharp1318

399311

answered Nov 10 at 5:19

John_Sharp1318

399311

add a comment |

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