Image Processing Performance Issue | JAI

Question

I am processing TIFF images to generate several JPG files out of it after applying image processing on it.
Following are the transformations applied:
1. Read TIFF image from disk. The tiff is available in form of a PlanarImage object
2. Scaling
     /* Following is the code snippet */
     PlanarImage origImg;
     ParameterBlock pb = new ParameterBlock();
     pb.addSource(origImg);
     pb.add(scaleX);
     pb.add(scaleY);
     pb.add(0.0f);
     pb.add(0.0f);
     pb.add(Interpolation.getInstance(Interpolation.INTERP_BILINEAR));
     PlanarImage scaledImage = JAI.create("scale", pb);3. Convertion of planar image to buffered image. This operation is done because we need a buffered image.
     /* Following is the code snippet used */
     bufferedImage = planarImage.getAsBufferedImage();4. Cropping
     /* Following is the code snippet used */
     bufferedImage = bufferedImage.getSubimage(artcleX, artcleY, 302, 70);The performance bottle neck in the above algorithm is step 3 where we convert the planar image to buffered image before carrying out cropping.
The operation typically takes about 1120ms to complete and considering the data set I am dealing with this is a very expensive operation. Is there an
alternate to the above mentioned approach?
I presume if I can carry out the operation mentioned under step 4 above on a planr image object instead of buffered image, I will be able to save
considerable processing time as in this case step 3 won't be required. (and that seems like the bottle neck). I have also noticed that the processing
time of the operation mentioned in step 3 above is proportional to the size of the planar image object.
Any pointers around this would be appreciated.
Thanks,
Anurag
Edited by: anurag.kapur on Oct 4, 2007 10:17 PM
Edited by: anurag.kapur on Oct 4, 2007 10:17 PM

Answer 1

It depends on whether you want to display the data or not.
PlanarImage (the subclass of all renderedOps) has a method that returns a Graphics object you can use to draw on the image. This allows you to do this like write on an image.
PlanarImage also has a getAsBufferedImage that will return a copy of the data in a format that can be used to write to Graphics objects. This is used for simply drawing processed images to a display.
There is also a widget called ImageCanvas (and ScrollingImagePanel) shipped with JAI (although it is not a committed part of the API). These derive from awt.Canvas/Panel and know how to render RenderedImage instances. This may use less copying/memory then getting the data as a BufferedImage and drawing it via a Graphics Object. I can't say for sure though as I have never used them.
Another way may be to extend JComponent (or another class) and customize it to use calls to PlanarImage/RenderedOp instances directly. This can hep with large tiled images when you only want to display a small portion.
matfud