Pipeline for finding cubes in the 2018 FTC game.

readme.txt

This is a sample image processing pipeline to extract cubes (glyphs) from an image
of an FTC competition arena.  The pipeline is as follows:

1. Resize the image.  This not only increases processing speed of subsequent functions,
   but also removes any higher-freqeuncy information that may cause problems with edge detection.
   (Like image sensor noise, aliasing, or high-frequency patterns in the mats and glyphs)

2. HSV Threshold.  This thresholds image colors to extract regions where the image is similar
   in color to the grey and brown glyphs.
   
3. Bitwise Or.  Combine the two HSV Threshold color masks to simplify extraction of cubes in general.
   Colors can be resegmented between brown and grey can be performed after the countours step.
   
4. Canny Edge Detection.  Extract color/edge transitions in the image.  The min and max thresholds are
   set to approximately emphasize major edge transitions and reduce noise.
   
5. Combine Thresholds and Edges.  Canny edges are binary not-ed so that edge transitions can be
   preserved in the HSV Threshold masks.  This is primarily used to better segment the grey cubes from
   the grey floor mats.  After the edges are inverted the image is binary and-ed with the HSV mask,
   and the resulting image has better masks for cube faces.
   
6. Find and Filter Contours.  Contours are extracted from the combined color and edge mask to find regions
   that approximate the faces of the cubes (Glyphs).  The filters are set such that only relatively large,
   square-ish contours remain.

Glyph_Pipeline.grip

<grip:Pipeline>
  <sources>
    <grip:ImageFile>
      <property name="path" value="glyph2.jpg"/>
    </grip:ImageFile>
  </sources>
  <steps>
    <grip:Step name="CV resize">
      <grip:Input step="0" socket="0"/>
      <grip:Input step="0" socket="1"/>
      <grip:Input step="0" socket="2">
        <value>0.15</value>
      </grip:Input>
      <grip:Input step="0" socket="3">
        <value>0.15</value>
      </grip:Input>
      <grip:Input step="0" socket="4">
        <value>INTER_LINEAR</value>
      </grip:Input>
      <grip:Output step="0" socket="0" previewed="true"/>
    </grip:Step>
    <grip:Step name="HSV Threshold">
      <grip:Input step="1" socket="0"/>
      <grip:Input step="1" socket="1">
        <value>
          <double>0.0</double>
          <double>180.0</double>
        </value>
      </grip:Input>
      <grip:Input step="1" socket="2">
        <value>
          <double>0.0</double>
          <double>47.19015280135823</double>
        </value>
      </grip:Input>
      <grip:Input step="1" socket="3">
        <value>
          <double>0.0</double>
          <double>151.0950764006791</double>
        </value>
      </grip:Input>
      <grip:Output step="1" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="HSV Threshold">
      <grip:Input step="2" socket="0"/>
      <grip:Input step="2" socket="1">
        <value>
          <double>0.0</double>
          <double>37.97872340425532</double>
        </value>
      </grip:Input>
      <grip:Input step="2" socket="2">
        <value>
          <double>43.220338983050844</double>
          <double>171.35638297872342</double>
        </value>
      </grip:Input>
      <grip:Input step="2" socket="3">
        <value>
          <double>9.6045197740113</double>
          <double>110.31914893617021</double>
        </value>
      </grip:Input>
      <grip:Output step="2" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="CV bitwise_or">
      <grip:Input step="3" socket="0"/>
      <grip:Input step="3" socket="1"/>
      <grip:Output step="3" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="CV Canny">
      <grip:Input step="4" socket="0"/>
      <grip:Input step="4" socket="1">
        <value>96.0</value>
      </grip:Input>
      <grip:Input step="4" socket="2">
        <value>29.0</value>
      </grip:Input>
      <grip:Input step="4" socket="3">
        <value>3</value>
      </grip:Input>
      <grip:Input step="4" socket="4">
        <value>false</value>
      </grip:Input>
      <grip:Output step="4" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="CV dilate">
      <grip:Input step="5" socket="0"/>
      <grip:Input step="5" socket="1"/>
      <grip:Input step="5" socket="2"/>
      <grip:Input step="5" socket="3">
        <value>1</value>
      </grip:Input>
      <grip:Input step="5" socket="4">
        <value>BORDER_CONSTANT</value>
      </grip:Input>
      <grip:Input step="5" socket="5"/>
      <grip:Output step="5" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="CV bitwise_not">
      <grip:Input step="6" socket="0"/>
      <grip:Output step="6" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="CV bitwise_and">
      <grip:Input step="7" socket="0"/>
      <grip:Input step="7" socket="1"/>
      <grip:Output step="7" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="Find Contours">
      <grip:Input step="8" socket="0"/>
      <grip:Input step="8" socket="1">
        <value>true</value>
      </grip:Input>
      <grip:Output step="8" socket="0" previewed="false"/>
    </grip:Step>
    <grip:Step name="Filter Contours">
      <grip:Input step="9" socket="0"/>
      <grip:Input step="9" socket="1">
        <value>60.0</value>
      </grip:Input>
      <grip:Input step="9" socket="2">
        <value>0</value>
      </grip:Input>
      <grip:Input step="9" socket="3">
        <value>41.0</value>
      </grip:Input>
      <grip:Input step="9" socket="4">
        <value>1000</value>
      </grip:Input>
      <grip:Input step="9" socket="5">
        <value>0</value>
      </grip:Input>
      <grip:Input step="9" socket="6">
        <value>1000</value>
      </grip:Input>
      <grip:Input step="9" socket="7">
        <value>
          <int>0</int>
          <int>100</int>
        </value>
      </grip:Input>
      <grip:Input step="9" socket="8">
        <value>1000000</value>
      </grip:Input>
      <grip:Input step="9" socket="9">
        <value>0</value>
      </grip:Input>
      <grip:Input step="9" socket="10">
        <value>0.6</value>
      </grip:Input>
      <grip:Input step="9" socket="11">
        <value>1.3</value>
      </grip:Input>
      <grip:Output step="9" socket="0" previewed="true"/>
    </grip:Step>
  </steps>
  <connections>
    <grip:Connection>
      <grip:Output step="0" socket="0" previewed="true"/>
      <grip:Input step="2" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="1" socket="0" previewed="false"/>
      <grip:Input step="3" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output source="0" socket="0" previewed="false"/>
      <grip:Input step="0" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="4" socket="0" previewed="false"/>
      <grip:Input step="5" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="7" socket="0" previewed="false"/>
      <grip:Input step="8" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="6" socket="0" previewed="false"/>
      <grip:Input step="7" socket="1"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="2" socket="0" previewed="false"/>
      <grip:Input step="3" socket="1"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="3" socket="0" previewed="false"/>
      <grip:Input step="7" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="0" socket="0" previewed="true"/>
      <grip:Input step="1" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="5" socket="0" previewed="false"/>
      <grip:Input step="6" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="0" socket="0" previewed="true"/>
      <grip:Input step="4" socket="0"/>
    </grip:Connection>
    <grip:Connection>
      <grip:Output step="8" socket="0" previewed="false"/>
      <grip:Input step="9" socket="0"/>
    </grip:Connection>
  </connections>
  <settings>
    <teamNumber>0</teamNumber>
    <publishAddress>roboRIO-0-FRC.local</publishAddress>
    <deployAddress>roboRIO-0-FRC.local</deployAddress>
    <deployDir>/home/lvuser</deployDir>
    <deployUser>lvuser</deployUser>
    <deployJavaHome>/usr/local/frc/JRE/</deployJavaHome>
    <deployJvmOptions>-Xmx50m -XX:-OmitStackTraceInFastThrow -XX:+HeapDumpOnOutOfMemoryError -XX:MaxNewSize=16m</deployJvmOptions>
  </settings>
  <codeGenerationSettings>
    <language>Java</language>
    <className>GripPipeline</className>
    <implementWpilibPipeline>false</implementWpilibPipeline>
    <saveDir>/home/jordanbrobots/GRIP</saveDir>
    <packageName></packageName>
    <moduleName>grip</moduleName>
  </codeGenerationSettings>
</grip:Pipeline>