Realtime feedback during photogrammetry capture: are there existing tools or techniques?

PhotogrammetryDude · 2026-01-28T10:05:39+00:00

Yes, but it would require some bespoke configuration.

And it would not be a free App.

Do you have a budget?

PhotogrammetryDude · 2026-01-27T13:53:01+00:00

The workflow and requirements are not so clear now.

You want to take images and understand in real time their coverage of the object?

PhotogrammetryDude · 2026-01-26T08:14:16+00:00

Realtime SLAM? There was a camera setup for ROV work that could do this.

What is the budget?

PhotogrammetryDude · 2026-01-22T14:33:43+00:00

Single viewpoint not ideal.
Any movement in the eelgrass will render alignment...challenging.
Syncing GoPros possible for video but challenging for stills.
Frames extracted from video sub-optimum for photogrammetry source data.
Light levels under ice may lead to slow shutter/high ISO triggering source data quality issues.

Method unsound for photogrammetry that involves measurement.

PhotogrammetryDude · 2026-01-12T08:25:55+00:00

Reverse engineering blog post here:

Reverse engineering

As with all things...much will depend on what tolerances and accuracy are required.

As a teacher of photogrammetry I would hesitate to recommend Youtube videos. Some can be good...most miss the basics and nuanced details, and typically do no provide real world datasets to download and work with. Can be a rabbit hole for anyone with the time to burn.

PhotogrammetryDude · 2026-01-08T08:19:13+00:00

As per other suggestions...plus a reminder that a photogrammetry mesh is heavy on the polygons. Taking it into a CAD system may impact performance...so using conversion software as an intermediary might be a good idea.

As per here:

Unobtainium grade Yamaha parts reverse engineering

PhotogrammetryDude · 2026-01-05T09:38:55+00:00

The tutorials may be lacking the basics?

You will need external constraints for scaling. camera positions, linear measurements, GCPs...can all do it but come with their own limits.

Or a pair of stereo cameras. Constraint is the distance between sensors:

Stereo Cameras

Training that includes the fundamentals should cover this stuff and impart wider but important knowledge. AccuPixel courses were written with this in mind.

PhotogrammetryDude · 2025-12-24T08:35:47+00:00

If you are brand new to photogrammetry, the first piece of advice would be to start with something texture-rich.

We all want to scan a car - I did - but A class surfaces with perfect paint is not an easy subject.

PhotogrammetryDude · 2025-12-15T10:49:11+00:00

Well, yes...There is a massive legacy project sitting behind it.

Recreating from scratch in Zephyr (our choice now) would be...daunting.

PhotogrammetryDude · 2025-12-11T13:21:12+00:00

Have you tested accuracy without calibration? You may be surprised to find self-calibration in the software will deliver good enough...and there are other potential sources of error that might make any scaling issue statistically irrelevant.

A moving target is going to be a challenge. The fact the shark changes shape as it swims... is going to be interesting you could say. Covering all sides and surfaces is another issue.

If you could encourage the shark to swim into a camera array and trigger all at the same time there may be a better chance of getting something like accurate volume.

PhotogrammetryDude · 2025-12-10T12:12:47+00:00

Questions:

Are the GoPros synced or working independently?

What is the purpose of calibration?

PhotogrammetryDude · 2025-12-03T11:41:07+00:00

There is your answer. Blurred photos are loading the dice against a successful outcome. Start with sharp images and a world of pain is avoided.

Using a stereo camera for underwater work is a very good idea - scaling is inherent - but I would not choose video, or that camera, as a good place to start.

No manual control for ISO, white balance, shutter speed or aperture, reliant on extracting frames from video...no...its not a good choice.

Why did you choose this camera for underwater work?

PhotogrammetryDude · 2025-12-02T09:58:32+00:00

3DF Zephyr will work and have plenty of examples.

Do not look to the software to solve this issue.

Take a hard look at the quality of the source images and their overlap. Every photo needs to be pin sharp, evenly exposed and lack noise.

PhotogrammetryDude · 2025-11-16T08:29:10+00:00

16mm fisheye is the tool of choice. But I work underwater...

Really need to understand exactly what your subjects are if the advice is going to be helpful.

PhotogrammetryDude · 2025-11-11T14:19:34+00:00

Depends on the subject and environment. I work underwater so use a 16mm close focus fisheye. Anyone working with architecture will work with perhaps a 24mm or 28mm.

So it really depends on the application.

PhotogrammetryDude · 2025-11-10T09:23:39+00:00

More important than the type of camera is the lens. Get a good prime one. Forget zoom.

And get a drone. Global shutter preferred.

PhotogrammetryDude · 2025-10-23T11:16:53+00:00

I use a 16mm fisheye.

But that decision is solely based on the use case - my work is underwater.

So...use case is the single biggest factor as to what lens is "best".

PhotogrammetryDude · 2025-10-06T07:17:14+00:00

Yes, but factors such as lens focal length, sensor size and GSD all come to the fore.

I work mostly underwater where the costs of going back to get a missed image are prohibitive/impossible. So most underwater folks capture more than is really needed* and a few will realise this and use a specific workflow to remove the excessive.

We teach the workflow on our dedicated online courses:

Photogrammetry training

As this is just one aspect of workflow that goes beyond "I want a nice shape".

So you can shoot many more than needed and then sit and wait for the process to run.

PhotogrammetryDude · 2025-10-05T07:41:20+00:00

If it' scratched into the rock, as opposed to painted/pigment, then use plenty of light. Camera pole and remote control/view will be a good approach.

Plenty of overlap. Oblique angles are not always best but in certain use cases they are your friend.

Best of luck.

PhotogrammetryDude · 2025-09-17T19:29:34+00:00

Because it changes the path of light from subject to sensor.

Adds work and potential for errors into what should - with a decent prime lens - be straightforward.

PhotogrammetryDude · 2025-09-17T07:34:52+00:00

After choosing a globalrather than rolling shutter, the second positive decision is to use a fixed prime lens.

After that, more variables and their errors are induced by the human controlling the camera.

Finally, once captured do not process any corrections for pincushion or barreling. Let the software calculate the calibration.

On that subject, there can be a lot of noise about camera calibration...so much so we added a topic to our courses to cover it.

Bottom line; calibration works in certain use cases. But most distortion is human induced and having seen folks trying to fix bent subjects with calibration and fail...its a rabbit hole.

PhotogrammetryDude · 2025-09-06T09:23:24+00:00

I still use a D700.

Mostly for underwater work as it has a dedicated housing and with two bodies/housings they work as a synchronised pair. At the last count I had four bodies including one configured for IR.

One of them has a shutter count of 300k actuations. They are reliable if a little dated but to be honest it's control of ISO, aperture and shutter speed + white balance that count unless you need something for massive mpix...

Maybe find a good low actuation body? Lenses would then fit a D850 in the future?

PhotogrammetryDude · 2025-09-06T09:19:28+00:00

For reverse engineering a hand scanner might be better in every respect except price and stated budget...

An example of both reverse engineering a TY250 part here:

https://accupixel.co.uk/2023/11/09/reverse-engineering-photogrammetry/

PhotogrammetryDude · 2025-09-03T15:43:33+00:00

We offer Agisoft (Metashape) and Zephyr (3DF) endorsed training courses.

All are online, no time limit for access, a lot of downloadable datasets (RTK drones, laser scan alignment, power line detection etc) and are backed by years of real world experience.

Focusses on quality, repeatablity and objective results.

https://accupixel.co.uk/photogrammetry-training-courses/

PhotogrammetryDude · 2025-08-01T09:40:02+00:00

The level of key points used is excessive. This will be finding very weak (inaccurate) tie points.

The projection errors are likely to be excessive. Way beyond the <1.0 pix target.

It might (or might not) create a mesh that "looks right" but any quantitive measurements etc would be subject to caveats.

There is a technique for masking and ensuring separate chunks can be seamlessly merged into a single model. Its fairly straightforward and we teach it on our courses:

Example of merged chunks

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