What cheap setup or technique works for truly flat photos for use in CAD? (lemmy.world)

submitted 5 days ago by j4k3@lemmy.world to c/asklemmy@lemmy.world

22 comments fedilink hide all child comments

I've managed to do reverse engineering of circuit boards using GIMP and rough alignment of layers using images like the one pictured. I want to use images to reverse engineer parts in CAD, but the minor lens distortion of a camera on a phone at ~20cm high on top of a stack of objects to keep it eyeballed flat is not enough. The result is off in multiple planes. There are minor errors in my curves in the transparent CAD part pictured, but the hole pattern is correct. The picture has been calibrated to 20mm against the ruler. Any suggestions on how to make this usable for replicating the ellipse that crosses the holes ±0.05mm?

you are viewing a single comment's thread
view the rest of the comments

[-] NeoNachtwaechter@lemmy.world 7 points 5 days ago* (last edited 5 days ago)

I see 2 problems. Both can be solved.

Position of the camera sensor plane parallel to your object's plane.

Place a sheet of squared paper on the table for the test shot. So you can see the proper alignment in both dimensions at once. Use a tripod to fix your camera above the table.

Tell the camera to insert a little time delay (3-5 seconds) when shooting to eliminate the motion from your finger's push.

(Edit: if you really want to stay very cheap, you could try without the tripod. But use the squared paper behind your object. Then do it all in the post processing).

Lens distortion.

Use a lens of a well known brand.(I don't know if it is possible with a phone instead of a real camera). Then use the software "darktable" for post processing, because it has a library of lenses and can properly correct the distortion with 1 click.

this post was submitted on 02 Jan 2025

45 points (97.9% liked)

Ask Lemmy

27352 readers

2473 users here now

A Fediverse community for open-ended, thought provoking questions

Rules: (interactive)

1) Be nice and; have fun

Doxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them

2) All posts must end with a '?'

This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?

3) No spam

Please do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.

4) NSFW is okay, within reason

Just remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either !asklemmyafterdark@lemmy.world or !asklemmynsfw@lemmynsfw.com. NSFW comments should be restricted to posts tagged [NSFW].

5) This is not a support community.

It is not a place for 'how do I?', type questions. If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email info@lemmy.world. For other questions check our partnered communities list, or use the search function.

6) No US Politics.

Please don't post about current US Politics. If you need to do this, try !politicaldiscussion@lemmy.world or !askusa@discuss.online

Reminder: The terms of service apply here too.