[kepler-users] Help understanding Kepler paradigm for batch processing images

[Ustun Yildiz]

I have the impression that you try to apply an operation (actor) to
the elements in a directory. In order to capture the names of such
elements and pipeline them into subsequent actors, I use

Directory Listing ---> Array to Sequence ---> Record Dissasembler

The first takes a directory name and the last outputs single names (as
many as the elements). The purpose of the Record Dissasembler is to
capture "name" element in the output of Array to Sequence actor. You
have to change the output port of Record Dissasembler to "name".

Ustun.




On Sat, Jul 11, 2009 at 12:51 PM, Jeremy
Douglass<jeremydouglass at gmail.com> wrote:
> I'm a new Kepler and struggling to apply a single actor (e.g. Image
> Converter) to a batch of objects (e.g. a directory of images, as
> represented by the array generated by Directory Listing).
>
> I've read the documentation and searched the forums, and tried
> modifying examples, but I'm not understanding something paradigmatic,
> and would appreciate a tip: how do you pipe an array of files through
> single-file actors?
>
> EXAMPLE:
>
> In Kepler 1.0.0, 03-ImageDisplay.xml uses an SDC director, and specifies:
>   Constant Image Filename --> Image Converter --> ImageJ
>
> In an attempt to converter a *directory* of images, I tried adding a
> Directory Listing actor:
>   Constant Dirname --> Directory Listing --> Image Converter --> ImageJ
>
> ...however this generates an error, as Image Converter will only act
> on a string, not an array. So I tried
>   Constant Dirname --> Directory Listing --> Array to Sequence -->
> Image Converter --> ImageJ
>
> ...which almost works if I hand-specified the number of Array elements
> in the directory ahead of time), but still only processed the first
> file listed in the string (Picture 1.png) -- I'm assuming it just
> throws the rest of the string away.
>
> I'm not understanding something about how one processes a list in a
> Kepler workflow -- I've looked through Array Operation and Iterative
> Operation actors, and none of them seem to be analogous to an
> imperative programming loop. Am I using the wrong kind of director?
> Something else?
>
> Thanks for your help.
>
> BACKGROUND: My larger goal is to adapt a frame based image processing
> workflow into Kepler (it is currently a combination of python,
> javascript, and bash scripts). To illustrate, one part of the workflow
> takes a heterogeneous collection of images (all file types and sizes)
> and copies them to a new directory as a collection of standardized
> collection jpegs. Another part of the workflow dumps a movie to a
> frame directory of jpegs, then runs multiple image measurement and
> image processing operations (e.g. ImageJ, MATLAB) on each frame and
> saves the results to a text file.
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