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Robotic Drawing of Pointillism Style Images

RBE 4815 B18 Team 6:

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Hannah Baez, Nikolas Gamarra, Ryan O’Brien, Jacob Remz,

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Project Description

  • Using expo markers to replicate images�in the artistic style of pointillism

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  • Pointillism is a technique in painting where small dots are used to form an image.

A Sunday Afternoon on the Island of La Grande Jatte

Painting by Georges Seurat

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Dithering(1:2)

  • Dithering is an application of noise that randomizes error

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  • A common use is converting grayscale to black and white

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  • On color images, can convert to three or six colors

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  • We used a Stucki dithering algorithm
    • Chooses a color for each pixel, then distributes error to subsequent pixels

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Dithering(2:2)

Colors Used:

Red, Green, Blue, Cyan, Magenta, Yellow,

Black, White

Colors Used:

Orange, Brown,

Black, White

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System Architecture

  • Python node sends control messages with ROS actionlib

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  • Sent motion goals of (x, y, z, r, p, y, tool, mode)

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  • Motion server executes goals using ROS-I and MoveIt

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  • Client reads force values from Arduino (Implemented but not used)

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Mechanical Design

  • Spring loaded Expo markers to maintain chisel tip integrity
  • Force sensing package mounted between tool flange and EOAT to prevent overloading
  • Multiple markers mounted radially to allow for more colors on same tooling
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Problem Solving

  • Determining prefered spring strength

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  • URDF corrections to improve motion

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  • Reorganized code to speed up drawing

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Calibration

  • Calibration of marker tip locations in X and Y

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  • Tuning of scaling factor to determine optimal point positioning

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Results

  • First attempt was a three color spiral
  • Attempted a six color 100x100 pixel drawing
  • For the sake of completion, we drew a simpler pixel art image

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cbputnam.jpg

Original image

cbputnam.png

100x100 pixels

cbputnam.png

300x300 pixels

Drawn By seurobot

100x100 pixels

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Questions?

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Works Cited

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https://drj11.wordpress.com/2009/04/03/dither-and-gamma/

https://www.widewalls.ch/pointillism-dotted-art/

https://www.metmuseum.org/toah/works-of-art/51.112.6/

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