Basic Image Clustering by Color

Hello everyone,

I'm pretty new to Rapidminer and Data Mining in general and wanted to try to cluster a collection of color images by color. After some time experimenting with rapidminer I managed to create a somewhat correct looking process, but I still get unidentified errors.

Below is the xml of my process.Note that this process is atm just clustering by general image features, not color in particular. Basically what I tried is loading images from multiple sources using the MCIO operator. As a subprocess of this, I use local feature extraction with POIs generated from an integral image source.
The resulting exampleset is then used for clustering by SVM.

Where did I go wrong with this process? Would you mind pointing out my mistakes and propose a possible solution?

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.013">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.013" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="imageprocessing:multiple_color_image_opener" compatibility="1.4.001" expanded="true" height="60" name="MCIO" width="90" x="45" y="30">
        <list key="images">
          <parameter key="birne" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\AbateFetelPear"/>
          <parameter key="acorn" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\Acorn"/>
          <parameter key="almond" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\Almond"/>
        </list>
        <parameter key="assign_label" value="true"/>
        <process expanded="true">
          <operator activated="true" class="multiply" compatibility="5.3.013" expanded="true" height="94" name="Multiply" width="90" x="45" y="30"/>
          <operator activated="true" class="imageprocessing:color_to_grayscale" compatibility="1.4.001" expanded="true" height="60" name="Color to grayscale (3)" width="90" x="179" y="120"/>
          <operator activated="true" class="imageprocessing:integral_image" compatibility="1.4.001" expanded="true" height="60" name="Integral Image" width="90" x="313" y="120"/>
          <operator activated="true" class="imageprocessing:interest_poin_detector" compatibility="1.4.001" expanded="true" height="60" name="interest_poin_detector" width="90" x="447" y="120">
            <parameter key="point_count" value="800"/>
          </operator>
          <operator activated="true" class="imageprocessing:feature_extraction_operator2" compatibility="1.4.001" expanded="true" height="94" name="Local Feature Extractor with Points" width="90" x="581" y="30">
            <process expanded="true">
              <operator activated="true" class="imageprocessing:color_to_grayscale" compatibility="1.4.001" expanded="true" height="60" name="Color to grayscale (4)" width="90" x="45" y="30"/>
              <operator activated="true" class="imageprocessing:contrast_of_gray_level_values" compatibility="1.4.001" expanded="true" height="60" name="contrast_of_gray_level_values" width="90" x="179" y="30"/>
              <connect from_port="image 1" to_op="Color to grayscale (4)" to_port="color image plus"/>
              <connect from_op="Color to grayscale (4)" from_port="grayscale image" to_op="contrast_of_gray_level_values" to_port="grayscale image plus"/>
              <connect from_op="contrast_of_gray_level_values" from_port="feature" to_port="feature 1"/>
              <portSpacing port="source_image 1" spacing="0"/>
              <portSpacing port="source_image 2" spacing="0"/>
              <portSpacing port="sink_feature 1" spacing="0"/>
              <portSpacing port="sink_feature 2" spacing="0"/>
            </process>
          </operator>
          <connect from_port="color image plus" to_op="Multiply" to_port="input"/>
          <connect from_op="Multiply" from_port="output 1" to_op="Local Feature Extractor with Points" to_port="color image plus"/>
          <connect from_op="Multiply" from_port="output 2" to_op="Color to grayscale (3)" to_port="color image plus"/>
          <connect from_op="Color to grayscale (3)" from_port="grayscale image" to_op="Integral Image" to_port="grayscale image plus"/>
          <connect from_op="Integral Image" from_port="integral image" to_op="interest_poin_detector" to_port="Integral Image"/>
          <connect from_op="interest_poin_detector" from_port="Points" to_op="Local Feature Extractor with Points" to_port="points"/>
          <connect from_op="Local Feature Extractor with Points" from_port="example set" to_port="Example set"/>
          <portSpacing port="source_color image plus" spacing="0"/>
          <portSpacing port="sink_Example set" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="support_vector_clustering" compatibility="5.3.013" expanded="true" height="76" name="Clustering (2)" width="90" x="246" y="30"/>
      <connect from_op="MCIO" from_port="example set" to_op="Clustering (2)" to_port="example set"/>
      <connect from_op="Clustering (2)" from_port="cluster model" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>

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StaryVena

Hello Rickyfox,
if you want to cluster images by color, it is maybe better to use global image features.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.009">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.009" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="imageprocessing:multiple_color_image_opener" compatibility="1.3.003" expanded="true" height="60" name="MCIO" width="90" x="45" y="30">
        <list key="images">
          <parameter key="birne" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\AbateFetelPear"/>
          <parameter key="acorn" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\Acorn"/>
          <parameter key="almond" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\Almond"/>
        </list>
        <parameter key="assign_label" value="true"/>
        <process expanded="true">
          <operator activated="true" class="imageprocessing:global_feature_extraction" compatibility="1.3.003" expanded="true" height="60" name="Global Feature Extractor from a Single Image" width="90" x="179" y="30">
            <process expanded="true">
              <operator activated="true" class="imageprocessing:statistics" compatibility="1.3.003" expanded="true" height="60" name="Global statistics" width="90" x="179" y="30"/>
              <operator activated="true" class="imageprocessing:histogram" compatibility="1.3.003" expanded="true" height="60" name="histogram" width="90" x="179" y="120"/>
              <operator activated="true" class="imageprocessing:color_to_grayscale" compatibility="1.3.003" expanded="true" height="60" name="Color to grayscale" width="90" x="45" y="165"/>
              <operator activated="true" class="imageprocessing:obcf" compatibility="1.3.003" expanded="true" height="60" name="OBCF" width="90" x="179" y="210"/>
              <connect from_port="color image plus 1" to_op="Global statistics" to_port="color image plus"/>
              <connect from_port="color image plus 2" to_op="histogram" to_port="color image plus"/>
              <connect from_port="color image plus 3" to_op="Color to grayscale" to_port="color image plus"/>
              <connect from_op="Global statistics" from_port="features" to_port="feature 1"/>
              <connect from_op="histogram" from_port="features" to_port="feature 2"/>
              <connect from_op="Color to grayscale" from_port="grayscale image" to_op="OBCF" to_port="grayscale image plus"/>
              <connect from_op="OBCF" from_port="features" to_port="feature 3"/>
              <portSpacing port="source_color image plus 1" spacing="0"/>
              <portSpacing port="source_color image plus 2" spacing="0"/>
              <portSpacing port="source_color image plus 3" spacing="0"/>
              <portSpacing port="source_color image plus 4" spacing="0"/>
              <portSpacing port="sink_feature 1" spacing="0"/>
              <portSpacing port="sink_feature 2" spacing="0"/>
              <portSpacing port="sink_feature 3" spacing="0"/>
              <portSpacing port="sink_feature 4" spacing="0"/>
            </process>
          </operator>
          <connect from_port="color image plus" to_op="Global Feature Extractor from a Single Image" to_port="color image plus"/>
          <connect from_op="Global Feature Extractor from a Single Image" from_port="example set" to_port="Example set"/>
          <portSpacing port="source_color image plus" spacing="0"/>
          <portSpacing port="sink_Example set" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="support_vector_clustering" compatibility="5.3.009" expanded="true" height="76" name="Clustering (2)" width="90" x="246" y="30"/>
      <connect from_op="MCIO" from_port="example set" to_op="Clustering (2)" to_port="example set"/>
      <connect from_op="Clustering (2)" from_port="cluster model" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>

If you want to use your process, what error appears?

Best,
Vaclav

Rickyfox

Thanks for your answer Vaclav,

when running my process I get a promt basically saying 'no obvious error encountered but something went wrong' . To have a better look at it I activated debug mode and got a 3744 error that shows that a Array Out of Bounds exception happened.

I'll use global features as suggested and come back here with my progres

Rickyfox

With most of the images in my collection being a fruit/vegetable in the center with white background (>70% of the screen in most cases) the background might be a problem for color clustering because on a testset of data I only get one cluster with all images in it.

Taking a closer look at the attributes of different images in this one cluster, I can see that the attribute distribution is pretty dense which explains why there is only one cluster.
Does anyone have an idea how I can fix this? Is it possible to automatically crop the images viewed by the process to the center of the image?

StaryVena

Hello Rickyfox,
maybe you can use segmentation, select segments which are not background, merge them and then use Crop Image By Mask Operator.

Best,
Vaclav

Rickyfox

StaryVena wrote:

Hello Rickyfox,
maybe you can use segmentation, select segments which are not background, merge them and then use Crop Image By Mask Operator.

Best,
Vaclav

How should I tackle that? If I use 'image_k_means' to segment the image it should use basic image features like color values etc in as attributes to segment by - is that a valid approach?
Also, what do I do with the segments I recieve? Would you mind elaborating what you mean by 'select segments which are not background' ?

StaryVena

Hello Rickyfox,
you can use this process:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.009">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.009" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="imageprocessing:open_color_image" compatibility="1.3.003" expanded="true" height="60" name="Open Color Image" width="90" x="45" y="30">
        <parameter key="filename" value="C:\Users\xuherv00\Pictures\fruit-questions-1.jpg"/>
        <parameter key="set_mask" value="false"/>
      </operator>
      <operator activated="true" class="multiply" compatibility="5.3.009" expanded="true" height="94" name="Multiply" width="90" x="112" y="120"/>
      <operator activated="true" class="imageprocessing:color_to_grayscale" compatibility="1.3.003" expanded="true" height="60" name="Color to grayscale" width="90" x="246" y="165"/>
      <operator activated="true" class="imageprocessing:statistical_region_merging" compatibility="1.3.003" expanded="true" height="60" name="statistical_region_merging" width="90" x="246" y="30">
        <parameter key="q" value="1"/>
      </operator>
      <operator activated="true" class="imageprocessing:segment_filter_by_order" compatibility="1.3.003" expanded="true" height="60" name="segment_filter_by_order" width="90" x="380" y="30"/>
      <operator activated="true" class="imageprocessing:merge_segments_to_image" compatibility="1.3.003" expanded="true" height="76" name="merge_segments_to_image" width="90" x="514" y="30"/>
      <operator activated="true" class="imageprocessing:cropimage" compatibility="1.3.003" expanded="true" height="76" name="Crop Image by Mask" width="90" x="514" y="165"/>
      <connect from_op="Open Color Image" from_port="color image plus" to_op="Multiply" to_port="input"/>
      <connect from_op="Multiply" from_port="output 1" to_op="statistical_region_merging" to_port="color image plus"/>
      <connect from_op="Multiply" from_port="output 2" to_op="Color to grayscale" to_port="color image plus"/>
      <connect from_op="Color to grayscale" from_port="grayscale image" to_op="Crop Image by Mask" to_port="greyscale image plus UV"/>
      <connect from_op="statistical_region_merging" from_port="segmented image" to_op="segment_filter_by_order" to_port="seg"/>
      <connect from_op="segment_filter_by_order" from_port="seg" to_op="merge_segments_to_image" to_port="segments"/>
      <connect from_op="merge_segments_to_image" from_port="segmeted image with one mask" to_op="Crop Image by Mask" to_port="greyscale image plus Y"/>
      <connect from_op="Crop Image by Mask" from_port="greyscale image plus UV" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="18"/>
      <portSpacing port="sink_result 2" spacing="126"/>
    </process>
  </operator>
</process>

Unfortunately it works only for gray scale images. But you can use the Evaluation version from http://www.burgsys.com/mumi-image-mining.php#tabs-1. It is free for non commercial use.

Best,
Vaclav

Rickyfox

StaryVena wrote:

Hello Rickyfox,
you can use this process:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.009">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.009" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="imageprocessing:open_color_image" compatibility="1.3.003" expanded="true" height="60" name="Open Color Image" width="90" x="45" y="30">
        <parameter key="filename" value="C:\Users\xuherv00\Pictures\fruit-questions-1.jpg"/>
        <parameter key="set_mask" value="false"/>
      </operator>
      <operator activated="true" class="multiply" compatibility="5.3.009" expanded="true" height="94" name="Multiply" width="90" x="112" y="120"/>
      <operator activated="true" class="imageprocessing:color_to_grayscale" compatibility="1.3.003" expanded="true" height="60" name="Color to grayscale" width="90" x="246" y="165"/>
      <operator activated="true" class="imageprocessing:statistical_region_merging" compatibility="1.3.003" expanded="true" height="60" name="statistical_region_merging" width="90" x="246" y="30">
        <parameter key="q" value="1"/>
      </operator>
      <operator activated="true" class="imageprocessing:segment_filter_by_order" compatibility="1.3.003" expanded="true" height="60" name="segment_filter_by_order" width="90" x="380" y="30"/>
      <operator activated="true" class="imageprocessing:merge_segments_to_image" compatibility="1.3.003" expanded="true" height="76" name="merge_segments_to_image" width="90" x="514" y="30"/>
      <operator activated="true" class="imageprocessing:cropimage" compatibility="1.3.003" expanded="true" height="76" name="Crop Image by Mask" width="90" x="514" y="165"/>
      <connect from_op="Open Color Image" from_port="color image plus" to_op="Multiply" to_port="input"/>
      <connect from_op="Multiply" from_port="output 1" to_op="statistical_region_merging" to_port="color image plus"/>
      <connect from_op="Multiply" from_port="output 2" to_op="Color to grayscale" to_port="color image plus"/>
      <connect from_op="Color to grayscale" from_port="grayscale image" to_op="Crop Image by Mask" to_port="greyscale image plus UV"/>
      <connect from_op="statistical_region_merging" from_port="segmented image" to_op="segment_filter_by_order" to_port="seg"/>
      <connect from_op="segment_filter_by_order" from_port="seg" to_op="merge_segments_to_image" to_port="segments"/>
      <connect from_op="merge_segments_to_image" from_port="segmeted image with one mask" to_op="Crop Image by Mask" to_port="greyscale image plus Y"/>
      <connect from_op="Crop Image by Mask" from_port="greyscale image plus UV" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="18"/>
      <portSpacing port="sink_result 2" spacing="126"/>
    </process>
  </operator>
</process>

Unfortunately it works only for gray scale images. But you can use the Evaluation version from http://www.burgsys.com/mumi-image-mining.php#tabs-1. It is free for non commercial use.

Best,
Vaclav

Thx I used another operator to crop the image to the center of my images, but thanks for the process.
Also, I downloaded the evaluation version which is a really great addition. My problem atm is, that I need an exampleset for the clustering process

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.013">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.013" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="image:read_image_set" compatibility="5.0.000" expanded="true" height="60" name="Read Image Set" width="90" x="45" y="120">
        <list key="categories">
          <parameter key="AbateFetelPear" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\AbateFetelPear"/>
          <parameter key="Acorn" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\Acorn"/>
        </list>
      </operator>
      <operator activated="true" class="loop_collection" compatibility="5.3.013" expanded="true" height="76" name="Loop Collection" width="90" x="246" y="120">
        <process expanded="true">
          <operator activated="true" class="image:crop_image" compatibility="5.0.000" expanded="true" height="60" name="Crop Image" width="90" x="45" y="30">
            <parameter key="x" value="1200"/>
            <parameter key="y" value="600"/>
            <parameter key="width" value="3637"/>
            <parameter key="height" value="2562"/>
          </operator>
          <operator activated="true" class="image:global_feature_extractor" compatibility="5.0.000" expanded="true" height="60" name="Global Feature Extractor (3)" width="90" x="246" y="30">
            <parameter key="include_label" value="false"/>
            <parameter key="include_color_type" value="true"/>
            <parameter key="include_dimensions" value="true"/>
            <process expanded="true">
              <operator activated="true" class="image:global_statistics" compatibility="5.0.000" expanded="true" height="60" name="Global Statistics" width="90" x="112" y="30"/>
              <operator activated="true" class="image:global_histogram" compatibility="5.0.000" expanded="true" height="60" name="Global Histogram" width="90" x="112" y="120">
                <parameter key="color histogram" value="false"/>
              </operator>
              <operator activated="true" class="image:order_based_block_color" compatibility="5.0.000" expanded="true" height="60" name="OBBC" width="90" x="112" y="210"/>
              <connect from_port="image 1" to_op="Global Statistics" to_port="image"/>
              <connect from_port="image 2" to_op="Global Histogram" to_port="image"/>
              <connect from_port="image 3" to_op="OBBC" to_port="image"/>
              <connect from_op="Global Statistics" from_port="feature" to_port="feature 1"/>
              <connect from_op="Global Histogram" from_port="feature" to_port="feature 2"/>
              <connect from_op="OBBC" from_port="feature" to_port="feature 3"/>
              <portSpacing port="source_image 1" spacing="0"/>
              <portSpacing port="source_image 2" spacing="0"/>
              <portSpacing port="source_image 3" spacing="0"/>
              <portSpacing port="source_image 4" spacing="0"/>
              <portSpacing port="sink_feature 1" spacing="0"/>
              <portSpacing port="sink_feature 2" spacing="0"/>
              <portSpacing port="sink_feature 3" spacing="0"/>
              <portSpacing port="sink_feature 4" spacing="0"/>
            </process>
          </operator>
          <connect from_port="single" to_op="Crop Image" to_port="image"/>
          <connect from_op="Crop Image" from_port="image" to_op="Global Feature Extractor (3)" to_port="image"/>
          <connect from_op="Global Feature Extractor (3)" from_port="example set" to_port="output 1"/>
          <portSpacing port="source_single" spacing="0"/>
          <portSpacing port="sink_output 1" spacing="0"/>
          <portSpacing port="sink_output 2" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="k_means" compatibility="5.3.013" expanded="true" height="76" name="Clustering" width="90" x="380" y="120"/>
      <operator activated="true" class="imageprocessing:create_clusters" compatibility="1.4.001" expanded="true" height="60" name="create_clusters" width="90" x="514" y="120"/>
      <connect from_op="Read Image Set" from_port="collection of images" to_op="Loop Collection" to_port="collection"/>
      <connect from_op="Loop Collection" from_port="output 1" to_op="Clustering" to_port="example set"/>
      <connect from_op="Clustering" from_port="cluster model" to_op="create_clusters" to_port="clusters"/>
      <connect from_op="Clustering" from_port="clustered set" to_port="result 2"/>
      <connect from_op="create_clusters" from_port="clusters" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
      <portSpacing port="sink_result 3" spacing="0"/>
    </process>
  </operator>
</process>

Here I use the feature extraction operators in the evaluation version which use the 'ima' input. I was forced to use 'read image set' because the rest of the data import operators for images do not return the necessary formats

StaryVena

Hello Rickyfox,
if you want to read multiple images from multiple folders, you have to use process similar to this one:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.013">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.013" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="loop_files" compatibility="5.3.013" expanded="true" height="76" name="Loop Files" width="90" x="112" y="30">
        <parameter key="directory" value="C:\Users\nick\Pictures\fruitveggiecollection\JPG\"/>
        <parameter key="file_name_macro" value="folder_name"/>
        <parameter key="file_path_macro" value="folder_path"/>
        <parameter key="parent_path_macro" value="folder_parent_path"/>
        <parameter key="iterate_over_files" value="false"/>
        <parameter key="iterate_over_subdirs" value="true"/>
        <process expanded="true">
          <operator activated="true" class="loop_files" compatibility="5.3.013" expanded="true" height="76" name="Loop Files (2)" width="90" x="246" y="30">
            <parameter key="directory" value="%{folder_path}"/>
            <process expanded="true">
              <operator activated="true" class="image:read_image" compatibility="5.0.000" expanded="true" height="60" name="Read Image" width="90" x="246" y="30">
                <parameter key="set_label" value="automatic"/>
                <parameter key="label" value="dfsf"/>
              </operator>
              <operator activated="true" class="image:crop_image" compatibility="5.0.000" expanded="true" height="60" name="Crop Image" width="90" x="447" y="30">
                <parameter key="x" value="1200"/>
                <parameter key="y" value="600"/>
                <parameter key="width" value="3637"/>
                <parameter key="height" value="2562"/>
              </operator>
              <operator activated="true" class="image:global_feature_extractor" compatibility="5.0.000" expanded="true" height="60" name="Global Feature Extractor (3)" width="90" x="715" y="30">
                <parameter key="include_color_type" value="true"/>
                <parameter key="include_dimensions" value="true"/>
                <process expanded="true">
                  <operator activated="true" class="image:global_statistics" compatibility="5.0.000" expanded="true" height="60" name="Global Statistics" width="90" x="447" y="30"/>
                  <operator activated="true" class="image:global_histogram" compatibility="5.0.000" expanded="true" height="60" name="Global Histogram" width="90" x="447" y="120">
                    <parameter key="color histogram" value="false"/>
                  </operator>
                  <operator activated="true" class="image:order_based_block_color" compatibility="5.0.000" expanded="true" height="60" name="OBBC" width="90" x="447" y="210"/>
                  <connect from_port="image 1" to_op="Global Statistics" to_port="image"/>
                  <connect from_port="image 2" to_op="Global Histogram" to_port="image"/>
                  <connect from_port="image 3" to_op="OBBC" to_port="image"/>
                  <connect from_op="Global Statistics" from_port="feature" to_port="feature 1"/>
                  <connect from_op="Global Histogram" from_port="feature" to_port="feature 2"/>
                  <connect from_op="OBBC" from_port="feature" to_port="feature 3"/>
                  <portSpacing port="source_image 1" spacing="0"/>
                  <portSpacing port="source_image 2" spacing="0"/>
                  <portSpacing port="source_image 3" spacing="0"/>
                  <portSpacing port="source_image 4" spacing="0"/>
                  <portSpacing port="sink_feature 1" spacing="0"/>
                  <portSpacing port="sink_feature 2" spacing="0"/>
                  <portSpacing port="sink_feature 3" spacing="0"/>
                  <portSpacing port="sink_feature 4" spacing="0"/>
                </process>
              </operator>
              <connect from_port="file object" to_op="Read Image" to_port="file"/>
              <connect from_op="Read Image" from_port="output" to_op="Crop Image" to_port="image"/>
              <connect from_op="Crop Image" from_port="image" to_op="Global Feature Extractor (3)" to_port="image"/>
              <connect from_op="Global Feature Extractor (3)" from_port="example set" to_port="out 1"/>
              <portSpacing port="source_file object" spacing="0"/>
              <portSpacing port="source_in 1" spacing="0"/>
              <portSpacing port="source_in 2" spacing="0"/>
              <portSpacing port="sink_out 1" spacing="0"/>
              <portSpacing port="sink_out 2" spacing="0"/>
            </process>
          </operator>
          <connect from_port="file object" to_op="Loop Files (2)" to_port="in 1"/>
          <connect from_op="Loop Files (2)" from_port="out 1" to_port="out 1"/>
          <portSpacing port="source_file object" spacing="0"/>
          <portSpacing port="source_in 1" spacing="0"/>
          <portSpacing port="sink_out 1" spacing="0"/>
          <portSpacing port="sink_out 2" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="append" compatibility="5.3.013" expanded="true" height="76" name="Append" width="90" x="246" y="30"/>
      <connect from_op="Loop Files" from_port="out 1" to_op="Append" to_port="example set 1"/>
      <connect from_op="Append" from_port="merged set" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>

Best,
Vaclav