Template Design

Template Design

A template is a .omrt document describing where everything is on your answer sheet: the four printed registration markers, the orientation mark, and each region of bubbles. Recognition follows the template, so a template that does not match the printed sheet produces confident nonsense — which is why the Template stage has a Validate button and the Calibrate stage exists.

This page orients you. The detailed, verified walkthrough — every toolbar action, the region types, the bubble-grid generation and the validation rules — is docs/template_designer.md. The .omrt format itself is docs/TEMPLATE_FORMAT.md.

The order of work

1. Load a reference image — a clean scan of a blank sheet, at the resolution you will scan the real ones.
2. Detect finds the four registration markers. Confirm accepts them. Adjust any that are wrong by dragging; everything else is positioned relative to these, so they come first.
3. Orientation sets the mark that tells OMRFlow which way up a page is.
4. Draw the regions:
   • Student ID — the candidate/roll number grid
   • Set — the question-paper set code
   • Questions — an answer block. Array creates a column of them and Distribute spaces them evenly, which is faster and more accurate than drawing each by hand
   • Custom — any other bubble region
   • Reference — a region to ignore, such as a logo or an instruction box
5. Edit Bubbles adjusts individual bubbles where the generated grid does not quite land; Reset regenerates the grid for a region.
6. Bubble radius sets the sampling radius.
7. Validate, then save.

Undo and redo cover the whole session.

Coordinates are normalised

A template stores positions relative to the canonical page the registration markers define, not in pixels of your reference image. The same template therefore works on scans at different resolutions, and a sheet that arrives rotated or skewed is corrected to the canonical page before anything is measured.

Getting started from the example

examples/templates/100_question_4_choice_example.omrt is a complete working template — a 100-question, four-choice sheet. Opening it and looking at how its regions are laid out is the fastest way to understand what the designer expects.

Before using a template for real

Run the Calibrate stage against several representative real scans. The template being geometrically valid is necessary and not sufficient: the recognition thresholds also have to suit your paper, printer and scanner. See Processing.

Related

• Processing
• Recognition Symbols
• docs/template_designer.md — the full walkthrough
• docs/TEMPLATE_FORMAT.md — the file format
• docs/IMAGE_PROCESSING.md — how a page is normalised