Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

ORB samples and ic_angle TSDoc use detector border 17, below describe()'s 20 px edge margin

Open Beginner friendly
  • Is something wrong?
#225 0 comments 0 reactions 0 assignees View on GitHub

Maintainers usually reply within 1 day

Nobody has claimed this yet.

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
92/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
typescript
Domain
computer-vision

Research direction

Inspect the three documented calls in examples/sample_orb.html, examples/sample_orb_pinball.html, and the ic_angle TSDoc example in src/orb/orb.ts. Change each detection border from 17 to 20, optionally preserving the rationale in the samples, then verify that no affected example still uses the smaller border.

Written by the indexing model from the issue text.

Description

Summary

The ORB samples and the orb.ic_angle() TSDoc example still detect keypoints with border = 17, which is below the ≥ 20 px edge margin that orb.describe() requires (documented in #146, closing #110). Keypoints detected 17–19 px from an edge therefore get descriptors partly built from rectify_patch's constant fill of 128 rather than image content — the exact silent contamination #110 describes.

Where

File Line Code
examples/sample_orb.html 311 var count = yape06.detect(img, corners, 17);
examples/sample_orb_pinball.html 348 var count = yape06.detect(img, corners, 17);
src/orb/orb.ts (TSDoc of ic_angle) 107 const count = jsfeatNext.yape06.detect(img, corners, 17);

(Checked at 2dfc8ab.)

Why 17 is not enough

From the describe() TSDoc added in #146: the furthest sample of the rotated pattern sits 13·√2 ≈ 18.4 px from the centre, plus the bilinear neighbour, so the safe margin is 20 px. The 360° rotation sweep measured contamination up to distance 18, vanishing from 19. A border of 17 sits inside the contaminated band.

ic_angle() itself only needs 15 px, so 17 is fine for orientation — the problem is only the describe() call that follows.

The TSDoc example is the most important one to fix: it is the snippet people copy, and it currently contradicts the margin note in the same class.

Proposed fix

Change the three occurrences from 17 to 20. No library behaviour changes; the samples lose a 3-px band of keypoints along each edge.

Optionally, for the samples: a short comment next to the call pointing at the describe() margin note, so the value doesn't drift again.

Related

  • #110 — the underlying silent-degradation issue
  • #146 — documented the 20 px margin (the samples were not updated)
  • #83 — where the optional runtime guard was folded

Generated by Claude Code

Dominant language
TypeScript
Stars
12
Forks
4
Avg merge
1d 17m
Merged PRs (30d)
28

Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from webarkit/jsfeatNext

All issues in webarkit/jsfeatNext

Similar issues

More TypeScript issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.