Photogrammetry - 3D scan with just your phone/camera

3D scanning with just your phone? In todays video we’re going to take a look at photogrammetry Most of us do not have access to high end 3D scanners, they can be quite expensive And they can also be somewhat limited in the size of the scanned object With photogrammetry all you’re gonna need is a camera and a reasonably powerful PC Before you start taking pictures, try and lit the object evenly from all sides and avoid creating hard shadows Circle around the object and try to get pictures from as many angles as possible Don’t forget to take pictures from top and bottom as well Do not move the object or it’s surroundings between shots The photogrammetry software is looking for features not only on your object, but also in the background, so this would really confuse it This is an example of a decent set of photos for photogrammetry There are lots of options in terms of software However most of them are either expensive or very limited in the free version We’ll be using Colmap, it’s available for all Windows, Mac and Linux For windows and Mac, you can donwload the pre-built binaries On windows you’ll find two batch files inside the downloaded archive One tests your machine and confirms, that everything is ready to run Colmap The other batch file launches the application Prepare 2 folders. One of them should include all your photos and the other will be used as an output directory In Colmap select Reconstruction - Automatic reconstruction Set the workspace folder, which is the output directory, and the Image folder, which is the one you just placed all your pictures in Change the quallity to medium and hit Run This can take a while, especially if you took a lot of pictures Colmap will show you the estimated camera positions and point preview of the tracked object To actually create a printable mesh, we’ll use Meshlab Import fused.ply file, which you’ll find in Colmap’s output directory Now you can see all the points that got reconstructed We only want to keep the points on our object, so we’ll delete everything else In our example, the extra points are various contrast features in the room we took the pictures in Use the Select vertexes tool from the main toolbar By holding down the Ctrl key, you can add to the selection Then click on the Delete vertices in the main toolbar Repeat this process until you’re left with mostly just the points representing the model to be reconstructed Select Filters - Remeshing - Screened Poisson Surface Reconstruction Change the Reconstruction depth to a value between 10 to 15 and hit Apply This make take a minute to process You can toggle visibility of objects in the top right corner with the eye icon This looks pretty rough, so let’s try to increase the reconstruction depth The higher value you’ll set, the longer it’s going to take to compute And at some point, usually at values above15, the model won’t get any more detailed This looks much better, we’ll use this model going forward. Here you can see the difference between reconstruction depth 14, 15 and 17 To get rid of the weird shape often generated at the bottom of your scanned object select Filters - Selection - Select faces with edges longer than. Toggle preview and adjust the Edge threshold value until the vast majority of the faces you want to delete are selected, but all faces you want to keep are still unselected Then use the delete faces tool from the main toolbar You can also use the select faces tool, which works the same way as the select vertexes tool You can smooth your model with the Laplacian Smooth Smoothing steps between 8-20 usually work well Be aware that too much smoothing will remove valuable detail from your model We are now ready to export the mesh Use PLY or 3DS if you want to keep the texture, for example for publishing the file online Or STL if you really want to save just the geometry of the model Doing photogrammetry with glossy objects is tricky Glossy surfaces will change in appearance as you circle around the object You can easily prevent this from happening with painters tape, which will add detail and created matte textured look Here you can see the difference this made on the reconstruction The same applies to transparent objects, like glass Spray it with chalk spray or cover it up with painters tape, otherwise the reconstruction won’t succeed Statues are perfect for photogrammetry Their surface is rough and won’t cast any reflections They have a lot of tiny features to be tracked and reconstruced Your model will amost always end up with a hole on the bottom But that’s very easy to fix in for example Meshmixer And in this case, it’s even better to just cut the stand and create a perfect surface to be placed on the print bed Check our older tutorials to learn how to these edits in Meshmixer Now you’re ready to slice and print your reconstructed model

Channel: Prusa 3D by Josef Prusa

Views: 2,052,299

Rating: 4.9244876 out of 5

Keywords: slicer, prusai3, Prusa Slicer, priginal prusa i3 mk3, Joe Prusa, 3D tiskárna, stavebnice, 3d tisk prusa, original prusa i3, 3d tiskárna prusa, Josef Prusa, Prusa i3 MK3, 3D tisk, Prusa MK2, Prusa Research, Prusa 3D printer, Prusa, Prusa i3, multimaterial, multi material, photogrammetry, 3D scan, 3D scanning

Id: ye-C-OOFsX8

Length: 7min 31sec (451 seconds)

Published: Fri Mar 23 2018

Reddit Comments

[u/squirreloak]

This is an interesting YouTube video about photogrammetry with just a phone, camera and free software.

[u/parundrum]

Can people just talk on videos anymore? Seems like they all have a chill downtempo music bed. Maybe I'm just grumpy today.

[u/P4guy]

I tried to make a good 3D model of a cliff face from my phone and it sucked. I’ll tell you what didn’t, when I help my drone and did it