2005.02.02 09:56 "[Tiff] Tiff differences", by Duarte Costa

2005.02.02 09:56 "[Tiff] Tiff differences", by Duarte Costa

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