geojasper includes a utility that conveniently compares a GeoTif
image to a GeoJp2 image. Greg Coats
$ geoimgcmp
Image Comparison Utility (Version 1.900.1).
usage:
geoimgcmp -f reference_image_file -F other_image_file [-m metric]
The metric argument may assume one of the following values:
psnr .... peak signal to noise ratio
mse ..... mean squared error
rmse .... root mean squared error
pae ..... peak absolute error
mae ..... mean absolute error
equal ... equality (boolean)
$ geoimgcmp -f 18stj940125.tif -F 18stj940125_kdu_reversible.jp2 -m rmse
geojasper info: GeoTiff found, size: 471
geojasper info: TIFF file decoded!
geojasper info: GeoJp2 info found...
0.000000
0.000000
0.000000
$ geoimgcmp -f 18stj940125.tif -F
18stj940125_kdu_irreversible10to1.jp2 -m rmse
geojasper info: GeoTiff found, size: 471
geojasper info: TIFF file decoded!
geojasper info: GeoJp2 info found...
3.706568
3.730488
4.409576
On Jan 21, 2009, at 3:59 AM, Jukka Rahkonen wrote:
Hi,
I have been suspecting that JP2ECW driver does not handle lossless
jpeg2000
images correctly and now I am pretty sure that it is true at least
with images
compressed with Kakadu.
I made a test by using FWTools 2.2.8 on Windows. I took a 100x100
pixel sized
test image in tif format and compressed in with Kakaku tool
'kdu_compress'
Command:
kdu_compress -i JP2ECW_test_original.tif -o kakadu.jp2 Creversible=yes
Then I decompressed the image with kdu_expand
Command:
kdu_expand -i kakadu.jp2 -o kakadu.tif
Then I converted kakadu.jp2 to tif with gdal_translate that has
JP2ECW driver as
default JPEG2000 driver.
Command:
gdal_translate -of gtiff kakadu.jp2 ecw.tif
Tiff image translated with kdu_expand is identical with the
original but the one
translated with gdal_translate for sure is not.
I would say that right now nobody should use JP2ECW driver for
handling lossless
JPEG2000 images.
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