| JPEG2000 compression [message #43496] |
Tue, 12 April 2005 10:48  |
Roberto Monaco
Messages: 11
Registered: August 2002
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Junior Member |
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I have a question regarding JPEG2000:
How do you control compression ratio when you save an image as JPEG2000
using the IDL object?
The following is curious: within a Photoshop plug-in I use to save JPEG2000
images, "they" define a compression factor. If I save the same image with
different compressions ratios (e.g. 1:1, 1:10, 1:40) I obviously get big
differences in the resulting file sizes. But if you read these files into
IDL objects, surprisingly all properties are exactly the same!! Same
dimensions for the data array, same bit_depth, same number of layers, etc.
?? This does not make any sense to me ... I must be overlooking at something
stupid?
Thanks for any tips.
Roberto
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| Re: jpeg2000 compression [message #66392 is a reply to message #43496] |
Wed, 13 May 2009 06:21  |
Jean H.
Messages: 472
Registered: July 2006
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Senior Member |
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> I
> also gave tiling a try, with various sizes of tile_dimensions. This
> had
> little effect. Smaller tiles actually resulted in a slightly larger
> jp2.
the tiles should only have an effect on the amount of memory required to
decode the image
Jean
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