[Insight-developers] how to make a procedural image?

[Paul Koshevoy]

Hi,

I need some advice on the implementation a large image mosaic class
(on the order of 500 tiles, where each tile is about 5000x5000
resolution).  Storing this mosaic in memory at full resolution is
not practical, because it's size will be roughly 11GB. I will
have to develop some kind of mechanism for on-demand assembly of the
required mosaic regions from the tiles stored on the file system.

I will need to do some image processing on the mosaic for automatic
feature detection -- processing with a Contrast Limited Adaptive
Histogram Equalization (CLAHE), building a Gaussian image pyramid as
well as Gradient image pyramid, subtracting two mosaics from each
other, thresholding, multiplying, etc...

What I've been doing so far, on a much smaller scale with mosaics of
12 tiles, is generating the mosaic image and operating on that
directly. Even for these small mosaics I had to down sample each
tile by a factor of 16 to speed up the feature detection.

I've been thinking about creating a procedural mosaic class that would
be like a read-only image, providing a subset of the interface of
itk::Image. I am not sure if that is useful. Would such a class be
usable with the ITK image filters such as the DiscreteGaussianImageFilter?

Or, should I instead develop an ITK independent mosaic class that
handles its memory management, and provide a method for generating an
itk::Image for a requested region of the mosaic?

Perhaps you have some other suggestions?

Thank you,
      Paul.