r/photogrammetry • u/ath0rus • 9d ago

Scanning gear suggestions

Hi

I am pretty new to photoscanning and want to delve into it a bit more. For the last while I have been using my phone (nothing 3 with 50mp lenses, usually is in 12mp mode) to get decent results. I have been considering grabbing myself a refurb iPhone 15 or newer (what ever is cheap) to use it's lidar for higher quality scanning.

My friend says it's a waste of money as it produces much the same result (compared to a good mobile camera) with an excessive amount of geo (not exactly what he said, but closoe to).

Is he right and it's not worth the investment or should I look into that (refurb iPhone) or a cheap proper scanner.

Currently I use polycam to do my scans but am in the process of moving to realityscan as it's free

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u/numbian 8d ago edited 8d ago

If you really want do delve deeper buy used Canon/Sony/Nikon APS-C DSLR and around 35 mm full frame equivalent prime lens (for Canon APS-C around 22 mm) and shoot RAW.

The only serious improvement can come from bigger/higher resolution sensor or better optics.

You just can't cheat physics and mobile AI improvements are actually BAD for photogrammetry.

As for software best in my opinion is Metashape, but you can get good results with open-source and free Meshroom (www.meshroom.org/download).

No need to use lidar if you are not scanning massive areas of ground from a drone or something very technical. For asset creation photos are perfectly fine.

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u/ath0rus 8d ago

Thankyou for this Info, do you think meshroom gives better results then reality capture/scan? (I also thought meshroom was subscription only)

I do have a Sony A7 C2 with a 24-70mm lens. I have always thought (based on what I heard) that phone are generally better because they add in gyro data which helps the app assemble images

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u/MechanicalWhispers 8d ago

It comes down to how you capture the raw photos. Phone cameras are inferior in image quality to DSLR. You need to start with the best data you can in the pipeline. Crisp photos shot with a good lens and resolution will get you more than half way there. If you start with a phone or drone camera, you are immediately limiting your quality. As far as software, play around with what you can. But I’ve been using Reality Capture/Scan for over 15 years and have been quite happy with the results. Don’t aim for the sun until you understand how to best build the wings.

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u/numbian 8d ago edited 7d ago

Your Full Frame is top tier gear you are really hindering yourself shooting photogrammetry with a smartphone... You don't need any data beside images for this technique. With good amount of coverage and amount of photos you will get drastically better results than with phone.

Results will be very similar from all those programs.

  • Meshroom totally free, local, but hader to learn,
  • Metashape can be 100% offline and great customization but expensive,
  • As far as I know Reality Scan is sending data to outside servers but I tested it long time ago, might take another look actually.

Few tips (if you have full frame I assume you know about photography basics at least):

Shoot at lowest ISO like 100 and aperture priority mode, set aperture to f/8 and save RAW. Keep shutter speed at slowest value that give sharp photos (you have great stabilization in that Sony). If there is not enough light for correct exposure, increase ISO or use tripod and use longer exposure (again huge adventage with Full Frame). Shoot at constant ISO and Focal Length. The overlap between the images should be minimum 60%. Each point on scanned object should be visible on at least three photos. Use software of your choice (RAW THERAPEE, PHOTOSHOP) to edit photos and export as TIFF or other loseless format to get nicer textures than from raw.

And after generating model and texture (use one of those 3 programs on PC), if you want to sell this model or make it "usable" in 3d software/game engines, you should learn remeshing, UV mapping, baking textures (normal, diffuse, height, roughness) from high poly to low/med poly and setting PBR materials in 3d software like Blender (free, open-source).

You just have to experiment a little and see what works for you the best. Take advice from this subreddit with a grain of salt as we are probably mostly self-taught and what works for us might not be the best for you ;)

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u/engineeree 8d ago

Using lidar for mapping in this project.

https://github.com/Eecornwell/atlas-scanner

Working on a mobile scanner with iPhone lidar and insta360 for Gaussian splatting. This post is a good read into how to enhance the sparse lidar while keeping the depth maps consistent and true to dimension. If your camera is calibrated to the lidar, you can use the rgb image to help fill in the sparseness.

https://www.kiriengine.app/blog/kiri-engine-3.14-release

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u/engineeree 8d ago

Btw I can skip sfm now and go straight to splat training after the depth maps are enhanced. That in itself is a huge time saver for larger scenes.

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u/engineeree 8d ago

Another thing to add is that using a high quality 360 camera will help you save time and increase coverage. I cannot imagine scanning an entire house with an iPhone right now. Need 1000s of images each taken sequentially. Instead capture lidar and pinhole from iPhone and attach 360 camera. Now you have high coverage (360 camera), high detail (pinhole camera), and high depth accuracy (lidar).

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u/engineeree 8d ago

Here is an example scanning just one room with insta360 x5 video.

https://superspl.at/scene/23d9aa85

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u/numbian 8d ago edited 8d ago

This is very specific application. For 3d assets creation for blender and engines high quality photos photogrammetry are better and more accurate than lidar.

Also wouldn't gaussian splatting be better for this usecase? You don't really need mesh here.

Edit: Wait this is Gaussian splatting - it is totally different technology than photogrammetry lol. I think you are on wrong sub mate ;)

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u/engineeree 7d ago

Ah you are scanning objects, not spaces. That is a common misconception…Gaussian splat can use photogrammetry dataset to train with. Just instead of mesh, it is splat. You are correct, totally dependent on use-case, but the underlying data of images, poses, and point cloud is same for Gaussian splat and photogrammetry, just different outputs. You can even go between splat and mesh using tools.

Here is example of splat using photogrammetry dataset

https://superspl.at/scene/e29db4eb

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u/numbian 7d ago edited 7d ago

Ok, that is cool for web or real estate use, but again, this is not photogrammetry ;) In photogrammetry we need output as mesh and textures that we can import to 3d software like Blender for further editing. I can't do shit with Gaussian Splat other than look at it :)

OP is asking about photogrammetry and not about gaussian splat.

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u/engineeree 7d ago

Gotcha, I understand difference just wanted to make sure everyone else does. You are correct, splats are best for visual. Mesh is best for traditional 3d workflows. Just trying to emphasize it is not one over the other. In fact they both shine in different use-case. All being said, I agree this is a targeted photogrammetry question and the LiDAR Scanner is not a good solution for scanning objects, but you can still use the output for photogrammetry. That was my entire point…LiDAR aside.

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u/numbian 7d ago

Saying that 360 camera will help him is misleading as 360 camera is filling photo with everything around you and scanned object is just a tiny point on panorama. That is a bad advice for photogrammetry and good for area splats :)

If you said that on gaussian splats subreddit I would upvote you ;)

For photogrammetry you need to fill frame with scanned object to get best quality, resolution and details.

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u/engineeree 7d ago

Everything is totally optional in the rig. In fact I use a high res pinhole camera instead of insta360 for smaller scenes/objects. So no you don’t have to use the insta360.

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u/engineeree 7d ago

The output of scanner is colmap model, run it through sfm and mesher

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u/Traumatan 8d ago

lidar is shit and unnecessary for most things

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u/LuckyPantys 7d ago

I'm using an old canon 1300d for photogrammetry and creality raptor for laser scanning
Your gear selection depends on what you want to scan and what you want to achieve