TIF file converted to PNG Pure Black about sharp HOT 4 OPEN

I think this image might be slightly corrupt (there are quite a few unknown TIFF tags) and/or have invalid/unexpected data.

This is likely to relate to bit depth - the image claims to be 16-bit but contains what appears to be 8-bit values.

Depth: 16/8-bit
Channel depth:
gray: 8-bit

Using vips at the command line, the maximum pixel value is only 161. I would expect this to be 65535.

$ vips max 澳门WGS84.tif
(vips:21878): VIPS-WARNING **: 12:40:10.974: Unknown field with tag 33550 (0x830e) encountered
(vips:21878): VIPS-WARNING **: 12:40:10.974: Unknown field with tag 33922 (0x8482) encountered
(vips:21878): VIPS-WARNING **: 12:40:10.974: Unknown field with tag 34735 (0x87af) encountered
...
161.000000

Do you know the source of this image e.g. which software was used to create it?

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@lovell Thanks!
I can use your method to convert TIF to digits and browse PNG thumbnails normally

I use the Python OpenCV library to implement it

The code is as follows

import cv2
image_16bit = cv2.imread('am.tif', cv2.IMREAD_UNCHANGED)
image_8bit = cv2.normalize(image_16bit, None, 0, 255, cv2.NORM_MINMAX, dtype=cv2.CV_8U)
cv2.imwrite('am2.tif', image_8bit)

am2.zip

But I cannot effectively convert TIF files to 8-bit using Sharp
Can Sharp find a way to solve the conversion problem?

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reply “Do you know the source of this image e.g. which software was used to create it?“

This TIF image is DEM digital elevation data captured by Advanced Land Observing Satellite 1
https://search.asf.alaska.edu/#/

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