empty `targets` list

[keighrim]

Bug Description

Originally reported by @wricketts

---

For some Sentence objects, we see targets are empty lists. While investigating the app code, I realized this is the only spot where the sentences' targets prop is written;

app-doctr-wrapper/app.py

Lines 134 to 141 in 780430f

	for word in line.words:
	if word.confidence > 0.4:
	start = text_document.text_value.find(word.value)
	end = start + len(word.value)
	token = self.Token(view.new_annotation(at_type=Uri.TOKEN), text_document, start, end)
	token_bb = create_bbox(view, word.geometry, "text", representative.id)
	create_alignment(view, token.region.id, token_bb.id)
	sentence.add_token(token)

So an empty targets list seems to mean the OCR result showed no words in that line...? In that case , I think this wrapper app should ignore such lines instead of generating empty sentences.

Reproduction steps

(screenshot from @wricketts 's report)

Expected behavior

No response

Log output

No response

Screenshots

No response

Additional context

No response

[keighrim]

Based on the newly documented input spec of the RFB (downstream) app (clamsproject/app-role-filler-binder#3), here's some additional implementation plans;

1. no more filtering out of low-confidence recognition results, and keep all tokens from the model
   • means all extraneous text from "screen bugs" (https://github.com/clamsproject/aapb-collaboration/issues/29) will be kept in the TextDocument
2. @text value should reflect the structure, even when it means to have redundant information available Sentence and Paragraph annotations
   • we actually talked about removing Sentence and Paragraph annotations to reduce the redundancty, but I realized that is not a good idea, in that it probably means that we also remove block- and line-level bounding boxes, and that's actually loss of information.
   • so for doing this, it's probably easier to build the @text values in bottom-up way, instead of using render() call available in the docTR library