Images loaded with "Image Reader (Table)" node are not closed?


I've been playing around with the image processing nodes for the first time today and they look quite exciting, thank you for the great work!

I'm currently simply trying to extract features for a big collection of images. My simplified workflow looks like this:

  1. Table with image paths
  2. Chunk Loop Start
  3. Image Reader (Table)
  4. Image Cropper (to get R/G/B channels)
  5. Image Features
  6. Loop end

Note that the result which is collected by the "Loop End" node does not contain any image cells, but only a bunch of numeric features. The mentioned workflow was running for a while and then suddenly failed with an exception stating "Too many open files". I checked for open files on the system and noticed that all of the processed image files from the dataset so far (8000+) were still open by KNIME (lsof | grep 'train_photos' | wc). (even when closing the workflow, the files remain open).

Is there anything I'm missing here? Do I need to close images manually?


[edit] Potentially related to this issue?

[edit2] Most recent KNIME 3.1 on Mac OS X 10.11.3

Hoi Philipp,

This is a bug. Can you tell me the image format (png, jpeg, tiff, ...?) or even provide me with a simple example workflow? Then I can try to reproduce the problem and fix it.

Thanks for reporting!


PS: Try the "Splitter" to get RGB ;-)

Hi Christian,

thank you for getting back! I'll send you a sample workflow via PM.


PS: Thx about the "Splitter" hint. Much more convenient!

Hi Philipp,

we fixed the problem and the fix will be available with the next bug-fix release. Thanks for the example workflow etc.



1 Like

Awesome, thank you guys!

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