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February 2005
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2005.02.02 09:56 "Tiff differences", by <duarte_costa@clix.pt>
Hello I have recently known about libtiff and all of the tiff issues, as a result of an issue my organization is dealing at this moment. We have rasterized some plants in a scanner. Next step would be the use of Intergraph's software IRAS/C to perform an image to map operation, thus we get georeferenced images. However, the results of this operation is not the expected, since the residual error values exceed all tolerances. In the past, with other scanner, we got tiff images that gave us nice results. I believe that this is a tiff internal structure issue, so to compare, both images, from the same plant, i gave you the structure read by TiffTagViewer. Tiff 1 - Size 211306 kb SubFileType (1 Long): Zero OldSubFileType (1 Short): 1 ImageWidth (1 Short): 8418 ImageLength (1 Short): 8568 BitsPerSample (3 Short): 8, 8, 8 Compression (1 Short): Uncompressed Photometric (1 Short): RGB Tresholding (1 Short): 1 FillOrder (1 Short): Msb2Lsb StripOffsets (17 Long): 276, 12930324, 25860372, 38790420, 51720468,... Orientation (1 Short): TopLeft SamplesPerPixel (1 Short): 3 RowsPerStrip (1 Long): 512 StripByteCounts (17 Long): 12930048, 12930048, 12930048, 12930048,... MinSampleValue (1 Short): 0 MaxSampleValue (1 Short): 1 XResolution (1 Rational): 300 YResolution (1 Rational): 300 PlanarConfig (1 Short): Contig ResolutionUnit (1 Short): Inch Tiff 2 - size 257296 kb SubFileType (1 Long): Zero ImageWidth (1 Short): 10576 ImageLength (1 Short): 8304 BitsPerSample (3 Short): 8, 8, 8 Compression (1 Short): Uncompressed Photometric (1 Short): RGB FillOrder (1 Short): Msb2Lsb Make (21 ASCII): i2s Digibook Scanner Model (23 ASCII): Suprascan A0 10000 RGB StripOffsets (1 Long): 8 Orientation (1 Short): TopLeft SamplesPerPixel (1 Short): 3 RowsPerStrip (1 Short): 31728 StripByteCounts (1 Long): 263469312 XResolution (1 Rational): 300 YResolution (1 Rational): 300 PlanarConfig (1 Short): Contig ResolutionUnit (1 Short): Inch Software (29 ASCII): Digibook Version :5, 4, 1, 0 DateTime (20 ASCII): 2005:01:19 12:04:27 HostComputer (9 ASCII): PUESTO2 Other fact is that IRASC/C takes much more time to read Tiff2 then Tiff1, despite their similarity in size. This loading time disparity is not detected when Photoshop is used. Detected main differences are related to strips. I think that Tiff 1 has more strips then Tiff 2. In this case, i think that Tiff2 is much more heavy (i am using 2Gb memory) Any feedback is welcomed in detecting differences that can cause this issues, as well as the best way to make tiff2 similar to tiff 1. thanks in advance D.Costa ----------------------------------- Chegou o Clix Turbo ADSL a 8 Megas Internet + Telefone sem assinatura telefónica Saiba mais em http://adsl.clix.pt