Photogrammetry vs. 'Real' 3D Scanner

In this video, we compare photogrammetry with a real, structured-light 3D scanner! I look at Detail reproduction, usability, cost and everything else that differentiates these two scanning technologies to help you decide which one is right for you!

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[wayneparris]

I used photo for a LOT of years in Aerospace to measure large tools and we never used it for 3D mapping.
We always used a lot of tie points (fixed points in space larger than the object under inspection that the camera could see from multiple angles. This helps to stitch the photos) We also used scale bars with accurately located targets of a highly accurate distance in multiple locations.
You can use reference points on the scale bars as tie points. The bars need to be in location for the whole photo session in all locations with known good distances.
LOL I almost cried for you when you said it takes roughly 15 min to process the photos. When we first started using Photo, we might have had 200 points to map and used 3 scale bars in X, Y, Z orientation so the software could establish scale in 3D. Add to that a hundred or so tie in points and we could measure 3 stories tall, 300 feet long and 30 feet wide in space to 0.015" (fifteen one THOUSANDTHS of an inch. Or less than half a MM.
Remember this is just points in space, not 3D mapping. We would load the pictures into the computer and start the computing at roughly Noon. THE NEXT MORNING when we came into work the computing MIGHT have been finished! LOL!
Leica came out a few times to try to sell us a scanner setup like what you show but on an industrial size and portable . It never worked for us. It was not as accurate as we needed and we did not need to have a detailed 3D map of the surface so we never did any of that.
We DID use Laser Trackers to do a lot of work and with multiple stations we could map the points in the tool referenced above to plus or minus 0.007" or less than half the error of photo and we could do it in an 8 hour shift or less start to finish.
The laser trackers were easy to use but were not as accurate as Theodolites. Theodolites could measure again to less than half the error of the laser tracker but it took a skilled 3 to 4 man team to do the same job as above.
It is all about the job that needs to be done as to what tool to use. We would map the critical points of joining the wings on an aircraft with Theodolites within the same 7 thou and that is a 3D object 250+ feet wide, 40 feet deep and roughly 4 to 6 feet thick in about 5 hours but again, we were not mapping the contour.
For mapping contour we would use Laser trackers set to measure a point every time the reflector moved a programmed distance, say every one tenth of an inch. We would sweep the reflector over the surface in a grid pattern then take that resulting hundreds of thousands of points and mesh them into a CAD model of what the part SHOULD be in a perfect world.
Uh LOL I guess most of this really does not apply! It is your fault LOL, measurements were my life for over 36 years and I guess I tend to get excited when I see tech being used that I used for so long :D Now that I am retired for 3 years, I miss it and talking about
If you made it this far.. GOD BLESS YOU! now CARRY on :P

[richardphatthenguyen]

Baby powder works well if you don't want to ruin your object with paint or anything. Apply on it prior to taking picture or scanning. It does increase the quality on shiny or darkish mat texture.

[Vatharian]

Einscan is based on open source technology. You can actually build your own from scratch. Actually, ideal for a Maker's project. The 'parent' project was called DAVID Laser Scaner, and it had two generations - first one used line laser (you had to buy the laser diode at prohibitively large cost of $5), and used motorized setup and video footage to generate vertex cloud, and second generation included a projector shining stripes onto the object with set of photographs - it increased the cost, but removed the need for perfect mechanical setup for moving laser, or at least prism or mirror. Einscan's dual camera setup is improvement over the original idea, btw which sprung around the time Microsoft's Kinect SDK became available. LED projectors can be had now for less than $15 (they have wild resolution of 320x240, but since all it does is display bars, it should be fine), so it's not that expensive.


Sadly DAVID's site was hit with users' data leak at some point, so it had some dark side to it.


Edit: I believe it might have been some time since I looked it up. It had became paid, closed software. What a shame :(

[timwilliams]

Tom, I love your channel and thanks for introducing some people to photogrammetry. Those with access to an SLR or at least a tripod with their phone are going to fair a lot better. Keep that Aperature up in the F11 range: the tripod will allow that shutter to be as slow as necessary. Most phones can be set to voice-operation, "cheese, cheese, cheese..." as the tripod gets moved around or the turntable spun with the object.
A light dusting of powder or a polarizer or both helps with the glares. Spray chalk is also great for items that are ok to rinse with water.
Those reading: please join some of the photogrammetry groups online and get ready for a vertical but satisfying learning curve!

[xile]

i brought an einscan a few months back. It works great and turns out 100% usable scans and models. I try the laser scanners and photo ones. They simply didnt work for me.
So i say if you needs a working scanner and have the money the Einscan SE is the way to go.
Also if you want to scan bigger thing its pretty easy to use a tripod and simply rotate the item for each scan.

[powertomato]

There is sophisticated all-in-one package photogrammetry 3D scan solutions out there as well. Although you don't need it and as you said, you can do it on the go, you always get better results with a calibrated well-known setup. By the way, the technique Einscan is using is called "stuctured-light scanning".
I think if you compared the two techniques of two machines in the same price range you wouldn't notice much of a difference accuracy-wise.

[Andrewatnanz]

You are practically one of the few Youtubes I can listen to and believe.

[robertlinder]

Add a polarizing filter to the camera. It will remove most reflections, except for the chrome skull.

[faxxzc]

Hi Tom, good video but i believe the einscan is also "just" a souped-up camera. They can measure the distances thanks to the projected lines and interpolate thanks to photogrammetry too, but this is not how "real" 3d scanners work. Real 3D scanners use Lasers to measure distances and give you a live preview of the appearing mesh and let you know where you have to go over again (yes you have the scanner hand-held and go around the subject to be scanned). Check out the Artec Eva and Artec Spider for "real" 3D scanners

[teresashinkansen]

For me is photogrammetry all the way, its incredibly versatile cheap and has pretty good precision if you know what you are doing, you can scan from insects to mountains!

[Isaacrl]

I know this is an older video, but I wanted to point out that there are now cellphone apps for photogrammetry that work about as well as shown here, but they generate the model automatically on the cellphone. It's pretty fast, but the detail levels haven't improved much.

[tinkertv]

It is indeed sad that EU approved article 13 :( My country is affected too.
Very nice comparison, Thomas! I love how you make your videos!
I used in the past the photogrammetry to scan some household stuff. It is good enough to get a rough model of a thing, but you always have to correct the scan in meshmixer or other software.
Keep up the good work! :) Cheers!

[rethonn]

I recommend dry shampoo spray for matting the objects (washes off with water)

[CenterpointConnect]

You know.... I woke up this morning not having a clue about this technology and now after your video randomly popping into my suggestions, I really am excited to try this out. Great subject matter!

[maficstudios]

Meshroom has its own limitations, and you can help deal with smoother surfaces with more photos with a higher res camera.

[craftedminer]

thanks nerdy pewdiepie, you helped me a lot bro.

[alanday]

If a specialized product is NOT better than a manual process the company is NOT doing their job.

[FabioFerrettiD]

Knowing your love for opensource, I'm supprised you didn't include opensource scanner like the cyclop, freelss or my sardauscan (it is hard to calibrate, but it only cost 30$ is much faster than 30min with decent machine and can be used to automate photogametry process)

[Dindonmasker]

It's really sweet of you to thank patreons who support other creators. It's gonna be more important now.

[MakerFarmNL]

Good subject! This is quite a question nowadays. I use photogrammetry for anatomical objects and with a 50 Megapixel camera I reach a level of detail that I could never reach with any other method, so for me and for many of us who already own a good camera, i would definitely conclude that for organically shaped objects photogrammetry is the way to go. Not for reverse engineering purposes perhaps and not for real-time capture needs of course.