This repostitory contains images of hand-drawn electrical circuit diagrams as well as accompanying annotation and segmentation ground-truth files.

The folder structure is made up as follows:

cghd
│   classes.json
└───drafter_D
│   └───annotations
│   │   │   CX_DY_PZ.xml
│   │   │   ...
│   │
│   └───images
│   │   │   CX_DY_PZ.jpg
│   │   │   ...
│   │
│   └───segmentation
│   │   │   CX_DY_PZ.jpg
│   │   │   ...
│
│   LICENSE
│   README.md

Where:

• D is the (globally) running number of a drafter
• X is the (globally) running number of the circuit (12 Circuits per Drafter)
• Y is the Local Number of the circuit's Drawings (2 Drawings per Circuit)
• Z is the Local Number of the Drawings's Image (4 Pictures per Drawing)

Every image is RGB-colored and stored as either jpg or jpeg.

A complete list of class labels including a suggested mapping table to integer numbers can be found in classes.json. The annotations contain bounding boxes of contained symbols and are stored in the PASCAL VOC format.

Segmentation images are available for some samples and bear the same resolution as the respective image files. They are considered to contain only black and white pixels indicating areas of drawings strokes and background respectively.

For some images, there are also netlist files available, which are stored in the ASC format.

The dataset ist still beeing extended and this repostiry is currently under construction. If you are interested in this domain and would like to contribute, please write an email to: [email protected]

If you use this dataset for scientific publications, please consider citing us as as follows:

@inproceedings{thoma2021public,
  title={A Public Ground-Truth Dataset for Handwritten Circuit Diagram Images},
  author={Thoma, Felix and Bayer, Johannes and Li, Yakun and Dengel, Andreas},
  booktitle={International Conference on Document Analysis and Recognition},
  pages={20--27},
  year={2021},
  organization={Springer}
}

These guidelines are used throughout the generation of the dataset. They can be used as an instruction for participants and data providers.

• 12 Circuits should be drawn, each of them twice (24 drawings in total)
• Most important: The drawing should be as natural to the drafter as possible
• Free-Hand sketches are preferred, using rulers and drawing Template stencils should be avoided unless it appears unnatural to the drafter
• Different types of pens/pencils should be used for different drawings
• Different kinds of (colored, structured, ruled, lined) paper should be used
• One symbol set (european/american) should be used throughout one drawing (consistency)
• It is recommended to use the symbol set that the drafter is most familiar with

• For each drawing, 4 images should be taken (96 images in total per drafter)
• Angle should vary
• Lighing should vary
• Moderate (e.g. motion) blur is allowed
• All circuit-related apsects of the drawing must be human-recognicable
• The drawing should be the main part of the image, but naturally occuring objects from the environment are welcomed
• The first image should be clean, i.e. ideal capturing conditions
• Kinks and Buckling can be applied to the drawing between individual image capturing

• General Placement
  • A symbol should be completely surrounded by its box
  • Boxes should be as tight as possible to the symbol
  • In case of connecting lines not completely touching the symbol, the bounding box should extended (only by a small margin) to enclose those gaps (epecially considering junctions)
• Annotations of subcomponents should be avoided (e.g. LED of an optocoupler)
• Junction annotations
  • Used for both actual junction points and wire line corners
  • Should not be used for corners or junctions that are part of the symbol definition (e.g. Transistors)
• Text annotations
  • Semmantically meaningful chunks of information
    • component characteristics enclosed in a single annotation (e.g. 100Ohms, 10% tolerance, 5V max voltage)
    • Component Terminal Labels
    • Individual Lines in text blocks
  • Texts not related to the Circuit should be ignored (e.g. Brief paper, Company Logos)
  • Characters which are part of the Symbol Definition should not be annotated (e.g. Schmitt Trigger S, and gate &, motor M, Polarized capacitor +)
    • Only add text annotation if they indicate non-standard terminals

• Areas of Intended drawing strokes (ink and pencil abrasion respectively) should be marked black, all other pixels (background) should be white
• shining through the paper (from the rear side or other sheets) should be considered background