Darkroom NotesSeason 3STIL.BIZPart 5 of 6
I stopped saying "the focus seems soft" — facing a placeholder number
A perfectly readable card sometimes got dropped with "the focus seems soft." Tracing the cause led to a gate placed before text recognition, and a single number left standing there. "Provisional — tune on device": a number marked that way, and then never touched again.
Last time was about freezing during continuous scans. Today, one more thing I fixed in the field. A readable card gets dropped before recognition even starts — and the cause was a single number left alone for too long.
"The focus seems soft"
Scan a card, and sometimes "the focus seems soft" appears and the read fails. But look at that card, and it's a perfectly readable one. Readable to the human eye, yet the app was rejecting it without so much as trying text recognition.
The cause: a number left alone
Looking into it, here was the setup. Before starting text recognition, STIL.BIZ placed a gate that measured the image's blur and rejected anything too blurry up front.
And the number the gate judged by carried a note, still attached: "provisional — tune on device." A placeholder, meant to be tuned properly later. But no one tuned it, and that provisional number kept standing at the gate.
A measured number drifts
A blur metric drifts a lot with lighting, the color of the card, the resolution. So deciding "reject before reading" by that one number means even a slightly soft but actually readable card gets dropped along with the rest. The gate was stopping the very ones it should have let through.
So I removed the gate
The fix was simple. Stop rejecting before reading.
Run every card through text recognition first. Let "is it readable" be decided not by a measured number but by the result of actually reading it. Only when recognition reads nothing at all is it a failure. And at that point, if the image is clearly blurry, then show "the focus seems soft" — that is, I demoted the blur number from rejecting cards to choosing the words.
I'd trusted the number too much
Looking back, this was a story of trusting a measured number too much.
Numbers are convenient. Set one threshold and you can sort mechanically. But what that number is quietly dropping is hard to see. One placeholder number had been dropping readable cards, all along, with no one noticing. What I fixed, perhaps, was less the code than my relationship with numbers. Anything you can measure is tempting to trust. But what decides "is it readable," in the end, isn't the gate — it's actually reading it.
Next time
Next is the finale. Tracing how a captured card becomes a contact, start to finish, and writing what I came to think after building a fourth tool — and with that, Darkroom Notes closes Season 3.
STIL.BIZ is out on the App Store.
