[SOLVED] 32-bit TIF conversion problems

[swharden]

I have a TIF containing data produced from a 12-bit camera, but it is saved as a 32-bit TIF. I am trying to convert it to JPG using the "convert" command line tool.

• My test image is here: http://swharden.com/tmp/im/test.tif
• The image looks great when opened in ImageJ: http://swharden.com/tmp/im/test.png
• convert test.tif out.jpg produces a flat white image
• convert test.tif -evaluate divide 16 -depth 8 out.jpg produces a flat gray image
• convert test.tif -contrast-stretch 0.15x0.05% out.jpg produces a flat white image

What command arguments can convert this 12-bit data in a 32-bit TIF to a simple JPG? Thanks in advance for your suggestions.

[snibgo]

First, we find what is in the image:

Code: Select all

magick identify -verbose test12.tiff

We get:

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  Geometry: 1392x1040+0+0
  Units: PixelsPerInch
  Colorspace: Gray
  Type: Grayscale
  Endianess: MSB
  Depth: 32/16-bit
  Channel depth:
    Gray: 16-bit
  Channel statistics:
    Pixels: 1447680
    Gray:
      min: 589815  (9)
      max: 5.09207e+007 (777)
      mean: 5.52102e+006 (84.2454)
      standard deviation: 773234 (11.7988)
      kurtosis: 32.3131
      skewness: -2.93325
      entropy: 0
  Colors: 127

Pixels are stored as floating-point data, grayscale. On a scale of 0.0 to 1.0, the minimum (smallest) value is 9. So processing this in the normal way will show all white.

The easiest way to get a visible image is "-auto-level" which reduces the range to 0.0 to 1.0, but with a low mean so also use "-auto-gamma" to raise the mean:

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magick test12.tiff -auto-level -auto-gamma out.png

This is IM v7. If using v6, use "convert" instead of "magick".

The output can be .jpg if you prefer.

[swharden]

Thank you for your input! Unfortunately my problem still is not solved.

This is the output of magick identify -verbose test.tif

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Image: test.tif
  Format: TIFF (Tagged Image File Format)
  Mime type: image/tiff
  Class: DirectClass
  Geometry: 1392x1040+0+0
  Units: PixelsPerInch
  Type: Bilevel
  Base type: Grayscale
  Endianess: MSB
  Colorspace: Gray
  Depth: 32/1-bit
  Channel depth:
    Gray: 1-bit
  Channel statistics:
    Pixels: 1447680
    Gray:
      min: 65535 (1)
      max: 65535 (1)
      mean: 65535 (1)
      standard deviation: 0 (0)
      kurtosis: 0
      skewness: 0
      entropy: -1.#IND
  Colors: 1
  Histogram:
   1447680: (4294967295,4294967295,4294967295) #FFFFFFFFFFFFFFFFFFFFFFFF gray(255)
  Rendering intent: Undefined
  Gamma: 0.454545
  Alpha color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: none
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1392x1040+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: TopLeft
  Properties:
    comment: ImageJ=1.48v
min=9.0
max=105.0

    date:create: 2018-08-01T10:03:32-04:00
    date:modify: 2018-07-30T15:40:17-04:00
    quantum:format: floating-point
    signature: d2d2c6e2965e3feb9390a5ea254753a088989feb8daa664b8834a9217e13c9c0
    tiff:alpha: unspecified
    tiff:endian: msb
    tiff:photometric: min-is-black
    tiff:rows-per-strip: 1040
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 5.791MB
  Number pixels: 1.448M
  Pixels per second: 45.24MB
  User time: 0.063u
  Elapsed time: 0:01.031
  Version: ImageMagick 7.0.2-0 Q16 x64 2016-06-12 http://www.imagemagick.org

I am surprised to see:

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      min: 65535 (1)
      max: 65535 (1)
      mean: 65535 (1)

magick test.tif -auto-level -auto-gamma out.png produces a solid black image.

My test image is here: http://swharden.com/tmp/im/test.tif
I still cannot figure out how to convert it to JPG with ImageMagick...

The image looks great when opened in ImageJ: http://swharden.com/tmp/im/test.png

Thank you in advance for your suggestions!

[snibgo]

quantum:format: floating-point

But you are using non-HDRI IM, which clamps values that are out of range, so the maximum value you can see is 1.0. To use IM on this file, you need an HDRI version.

[swharden]

Thanks for your reply! I now understand.

My problem was: The ImageMagick I had on my system did not support 32-bit images. I required a HDRI (high dynamic range imaging) build of ImageMagick. This is described on https://www.imagemagick.org/script/high ... -range.php

The fix was: Download a HDRI build of ImageMagick from https://www.imagemagick.org/script/download.php

magick identify -verbose test.tif now outputs:

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Image: test.tif
  Format: TIFF (Tagged Image File Format)
  Mime type: image/tiff
  Class: DirectClass
  Geometry: 1392x1040+0+0
  Units: PixelsPerInch
  Colorspace: Gray
  Type: Grayscale
  Endianess: MSB
  Depth: 32/16-bit
  Channel depth:
    Gray: 16-bit
  Channel statistics:
    Pixels: 1447680
    Gray:
      min: 589815  (9)
      max: 5.09207e+007 (777)
      mean: 5.52102e+006 (84.2454)
      standard deviation: 773234 (11.7988)
      kurtosis: 32.3131
      skewness: -2.93325
      entropy: 0
  Colors: 127
  Histogram: [omitted for simplicity]
  Rendering intent: Undefined
  Gamma: 0.454545
  Matte color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: none
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1392x1040+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: TopLeft
  Properties:
    comment: ImageJ=1.48v
min=9.0
max=105.0

    date:create: 2018-08-01T16:42:49-04:00
    date:modify: 2018-08-01T16:42:46-04:00
    quantum:format: floating-point
    signature: 9ad4d28f2dd7badefc9ddd20436c9f00429b55124b343204028f3fb889b768e9
    tiff:alpha: unspecified
    tiff:endian: msb
    tiff:photometric: min-is-black
    tiff:rows-per-strip: 1040
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 5.52263MiB
  Number pixels: 1447680
  Pixels per second: 51.7031MB
  User time: 0.031u
  Elapsed time: 0:01.027
  Version: ImageMagick 7.0.8-8 Q16 x64 2018-07-23 http://www.imagemagick.org

Now this command works for me:
magick test.tif -auto-level -auto-gamma out.png

Personally I enjoy:
convert test.tif -auto-level -contrast-stretch 0.15x0.05% out.png

Thanks!