# RGB value ranges 0-1 after rescaling, How do I normalize images?

I wrote a class to rescale images, but the RGB value became ranging from 0 to 1 after preocessing. What happened to the RGB which intuitively should be ranging from 0-255 ? Following are the Rescale class and the RGB values after rescaling.

Question:

1. Do I still need a Min-Max Normalization, map the RGB value to 0-1?

2. How do I apply transforms.Normalization, where do I put the Normalization, before or after the Rescale, how do I calculate the mean and variance, use the RGB value ranging from 0-255 or 0-1？

``````class Rescale(object):
def __init__(self, output_size):
assert isinstance(output_size, (int, tuple))
self.output_size = output_size

def __call__(self, sample):
image, anno = sample['image'], sample['anno']

# get orginal width and height of image
h, w = image.shape[0:2]
# if output_size is an integer

if isinstance(self.output_size, int):
if h > w:
new_h, new_w = h * self.output_size / w, self.output_size
else:
new_h, new_w = self.output_size / h, w * self.output_size / h

# if output size is a tuple (a, b)
else:
new_h, new_w = self.output_size
new_h, new_w = int(new_h), int(new_w)

image = transform.resize(image, (new_h, new_w))
return {'image': image, 'anno': anno}
``````
``````[[[0.67264216 0.50980392 0.34503034]
[0.67243905 0.51208121 0.34528431]
[0.66719145 0.51817184 0.3459951 ]
...
[0.23645098 0.2654311  0.3759458 ]
[0.24476471 0.28003857 0.38963938]
[0.24885877 0.28807445 0.40935877]]

[[0.67465196 0.50994608 0.3452402 ]
[0.68067157 0.52031373 0.3531848 ]
[0.67603922 0.52732436 0.35839216]
...
[0.23458333 0.25195098 0.36822142]
[0.2461343  0.26886127 0.38314558]
[0.2454384  0.27233056 0.39977664]]

[[0.67707843 0.51237255 0.34766667]
[0.68235294 0.5219951  0.35553024]
[0.67772059 0.52747687 0.35659176]
...
[0.24485294 0.24514568 0.36592999]
[0.25407436 0.26205475 0.38063318]
[0.2597007  0.27202914 0.40214216]]

...

[[0.2957549  0.37119608 0.35928922]
[0.30588235 0.37932353 0.36563725]
[0.31078569 0.38772197 0.36392157]
...
``````

The following is RGB values before scaling

``````[[[172 130  88]
[172 130  88]
[172 130  88]
...
[ 63  74 102]
[ 65  76 106]
[ 67  77 112]]

[[173 131  89]
[173 131  89]
[173 131  89]
...
[ 65  74 103]
[ 64  75 105]
[ 63  73 108]]

[[173 131  89]
[174 132  90]
[174 132  90]
...
[ 63  72 101]
[ 62  71 102]
[ 61  69 105]]

...
``````