Recognition Symbols

Recognition Symbols

What OMRFlow writes when a mark is not a single clean answer. These values appear in the Scan table, the Resolve queue, CSV exports and the Processing Log sheet of a generated report.

The rule behind all of them: OMRFlow never resolves an ambiguous mark silently. If it cannot read a bubble confidently, it says so and sends it to a person.

Answer values

Symbol	Meaning
A, B, C, D, …	One bubble marked, confidently. The answer
_	Blank — no bubble marked, and the darkest candidate is confidently below the blank threshold
B-D	Multiple marks — two or more bubbles marked. Every mark is kept, joined by -, so nothing is discarded
(empty)	No value recorded for this question

A multiple-mark value lists all the marks it found, in order: A-C, B-D, even A-B-C-D. It is never reduced to "the darkest one" — which bubble a candidate meant is not a decision software should make.

Mark statuses

Each recognised field carries a status as well as a value:

Status	Meaning
resolved	Read confidently. The value stands
blank	Confidently nothing marked
multiple	Two or more marks, all kept
uncertain	Read, but not confidently — either the darkest mark is too close to the next darkest, or the darkest sits between the blank and marked thresholds. The value is still recorded, and the field is flagged for review
unreadable	The field could not be measured at all

uncertain is the status the Calibrate stage exists to reduce: it usually means the recognition thresholds do not match your scanner and paper. See Processing.

Sheet statuses

Each sheet in a batch has one of these:

Status	Meaning
pending	Imported, not yet processed
queued	Waiting for a worker
processing	Being read now
completed	Read, with nothing needing attention
warning	Read, but something needs review — an uncertain field, a multiple mark, or a registration concern
failed	Could not be processed. Usually registration: the four printed markers could not be found, so the page could not be aligned
cancelled	The batch was stopped before this sheet was read

completed and warning both mean the sheet was read. warning is not an error; it is OMRFlow asking you to look.

What to do about each

You see	Do this
Many uncertain fields	Run the Calibrate stage against representative scans and adjust the thresholds
Many failed sheets	Check the scan resolution, that the whole page including all four markers is on the image, and that the template matches the printed sheet
multiple marks	Resolve each in the Resolve stage. This is a candidate behaviour, not a recognition fault
_ where you expected an answer	Usually genuine. Check one against the paper to be sure the threshold is not too strict

Related

• Processing — the Calibrate stage and thresholds
• Review & Resolution — deciding flagged fields
• docs/recognition_engine.md — how the decision is actually made, with the thresholds named