about tiff image

imfinfo of my image gives the following:

Filename: 'drosophila.tif'
                  FileModDate: '10-Nov-2009 18:52:42'
                     FileSize: 264768
                       Format: 'tif'
                FormatVersion: []
                        Width: 512
                       Height: 512
                     BitDepth: 8
                    ColorType: 'grayscale'
              FormatSignature: [73 73 42 0]
                    ByteOrder: 'little-endian'
               NewSubFileType: 0
                BitsPerSample: 8
                  Compression: 'PackBits'
    PhotometricInterpretation: 'BlackIsZero'
                 StripOffsets: [32x1 double]
              SamplesPerPixel: 1
                 RowsPerStrip: 16
              StripByteCounts: [32x1 double]
                  XResolution: 72
                  YResolution: 72
               ResolutionUnit: 'Inch'
          开发者_如何学C           Colormap: []
          PlanarConfiguration: 'Chunky'
                    TileWidth: []
                   TileLength: []
                  TileOffsets: []
               TileByteCounts: []
                  Orientation: 1
                    FillOrder: 1
             GrayResponseUnit: 0.0100
               MaxSampleValue: 255
               MinSampleValue: 0
                 Thresholding: 1
                       Offset: 264322

how many strips are there?

generic logic:

  ceil(Height/RowsPerStrip)

The TIFF specifications states that the last strip need not be full (hence the CEIL call).

Or, the length of the StripOffsets from the info structure. As the name implies, this is a vector of byte offsets to each strip in the file (so there has to be one offset per strip).

32.

Height: 512
RowsPerStrip: 16

512 = 2^9; 16=2^4. Divide to get 2^5 which is 32.