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Can number of resolution levels be different for different components in a single jp2 image?

For example,

maxlevel = 5 for component 1
maxlevel = 7 for component 2
mexlevel = 5 for component 3
maxlevel = 5 for component 4

Correct me if any.

Manish Gautam
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1 Answers1

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Yes, you can specify a different number of wavelet decomposition levels for each component (in fact, for each tile-component). Of course, the number of wavelet decomposition levels is also the number of resolution levels available.

If you are using the Kakadu implementation (www.kakadusoftware.com), the parameters would look something like

Clevels:C0=5 Clevels:C1=7 Clevels:C2=5 Clevels:C3=5

In fact, you can omit everything except Clevels:C1=7, because 5 levels are applied by default.

If you use another JPEG2000 implementation, then you will need to see whether this option is available.

(Edited answering comments): In general, using more than 5 decomposition levels will not give you any extra functionality or coding performance. Roughly explained, the first level divides the image into 4 approximately equal parts. The second level takes the top left quarter and divides it into 4 parts, and so on. Each resolution level besides the original image has the same size as one of this top-left corners, at the first, second or n-th level. Because of this:

  • Adding extra levels will only add very small resolution levels, unless the original image is very large
  • In terms of coding performance, you won't see any noticeable changes unless, again, if the original image is huge.
mhernandez
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  • "If you use another JPEG2000 implementation, then you will need to see whether this option is available." Which option are you talking about? Is "Clevels:C1=9" a valid value? – Manish Gautam Jan 30 '17 at 06:27
  • What about max level values for different components? Can max level values for different component be different? – Manish Gautam Jan 30 '17 at 06:59
  • @mhernandez interesting. Why would someone want to use different number of decompositions for different components ? – Jacko Jan 31 '17 at 16:47
  • @Jacko Good question. You probably don't for normal images, but perhaps you do for huge synthetic ones, for instance if you don't want to use the DWT in one or more components... – mhernandez Jan 31 '17 at 17:39
  • @mhernandez not to nitpick, but `resolution levels = decomposition levels + 1` . – Jacko Jan 31 '17 at 23:50
  • @mhernandez thanks, it makes sense to skip dwt on synthetic components that will not benefit from transform – Jacko Jan 31 '17 at 23:52
  • @manish-gautam Yes, it should be a valid value. And yes, since resolution levels equals the number of decomposition levels + 1 (thaks Jacko for pointing that out), you can set any number of levels for each component independently. – mhernandez Feb 01 '17 at 17:38