Problem reading 16bit grayscale image

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Dimitris M 2013-10-11

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https://ww2.mathworks.cn/matlabcentral/answers/89885-problem-reading-16bit-grayscale-image

评论： Image Analyst 2013-10-11

Hello

I have a strange problem when trying to read in a grayscale image of 16bit. So despite the fact that these images are well displayed in some other software I use, when I am trying to load them in Matlab as tiff files a very strange thing occurs.

So the images are read in as uint16 (which is correct). Some values such as the maximum are also detected correctly but the most of the rest values are imported as zeros, which is absolute wrong !

I trying to read them both with imread() and geotiffread() --- as these files are georeferenced images

Do you know what may be the reason for such a problem ?

Thanks in advance

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Dimitris M 2013-10-11

No one had similar problem before ?

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Answer 1

Sean de Wolski 2013-10-11

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编辑：Sean de Wolski 2013-10-11

在 MATLAB Online 中打开

Perhaps they should be int16's and the values below zero are saturating to zero since they can't be represented as a uint16?

If you could attach an image, that would help.

More per size clarification

It sounds like the file might actually be a BigTIFF file. You could try using the MATLAB interface to LibTIFF to see if it can be read directly from there:

doc tiff

You can also read in just certain tiles at a time.

This blog may interest you as well:

http://blogs.mathworks.com/steve/2013/08/07/tiff-bigtiff-and-blockproc/

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Dimitris M 2013-10-11

编辑：Dimitris M 2013-10-11

在 MATLAB Online 中打开

Thanks for the tip - I will look into it

Nevertheless this are the metadata I was able to retrieve with imfinfo()

If you see anyhing 'strange' with it let me know ( this is the small tile file)

                  FileSize: 9579
                         Format: 'tif'
                  FormatVersion: []
                          Width: 57
                         Height: 53
                       BitDepth: 16
                      ColorType: 'grayscale'
                FormatSignature: [73 73 42 0]
                      ByteOrder: 'little-endian'
                 NewSubFileType: 0
                  BitsPerSample: 16
                    Compression: 'Uncompressed'
      PhotometricInterpretation: 'BlackIsZero'
                   StripOffsets: []
                SamplesPerPixel: 1
                   RowsPerStrip: 4.2950e+09
                StripByteCounts: []
                    XResolution: 1
                    YResolution: 1
                 ResolutionUnit: 'None'
                       Colormap: []
            PlanarConfiguration: 'Chunky'
                      TileWidth: 64
                     TileLength: 64
                    TileOffsets: 8
                 TileByteCounts: 8192
                    Orientation: 1
                      FillOrder: 1
               GrayResponseUnit: 0.0100
                 MaxSampleValue: 65535
                 MinSampleValue: 0
                   Thresholding: 1
                         Offset: 8890
                       Software: [1x163 char]
                   SampleFormat: 'Unsigned integer'
             ModelPixelScaleTag: [1.2500 1.2500 0]
               ModelTiepointTag: [0 0 0 6.9696e+05 4.1508e+06 0]
             GeoKeyDirectoryTag: [1x24 double]
              GeoAsciiParamsTag: [1x130 char]

Dimitris M 2013-10-11

在 MATLAB Online 中打开

This is my large file - with which I have a problem !

                FileSize: 3.9159e+09
                       Format: 'tif'
                FormatVersion: []
                        Width: 36800
                       Height: 53200
                     BitDepth: 16
                    ColorType: 'grayscale'
              FormatSignature: [77 77 0 42]
                    ByteOrder: 'big-endian'
               NewSubFileType: 0
                BitsPerSample: 16
                  Compression: 'Uncompressed'
    PhotometricInterpretation: 'BlackIsZero'
                 StripOffsets: [1x53200 double]
              SamplesPerPixel: 1
                 RowsPerStrip: 1
              StripByteCounts: [1x53200 double]
                  XResolution: []
                  YResolution: []
               ResolutionUnit: 'Inch'
                     Colormap: []
          PlanarConfiguration: 'Chunky'
                    TileWidth: []
                   TileLength: []
                  TileOffsets: []
               TileByteCounts: []
                  Orientation: 1
                    FillOrder: 1
             GrayResponseUnit: 0.0100
               MaxSampleValue: 65535
               MinSampleValue: 0
                 Thresholding: 1
                       Offset: 3.9155e+09
       ModelTransformationTag: [1.2500 0 0 662500 0 -1.2500 0 4214000 0 0 0 0 0 0 0 1]
           GeoKeyDirectoryTag: [1x52 double]
           GeoDoubleParamsTag: [0 500000 0.9996 117 0]
            GeoAsciiParamsTag: 'Zone utm50N|'