Category Archives: VIDEO

PHOTOGRAPHY TIPS FOR PHOTOGRAMMETRY

EQUIPMENT

For quick shoots, any digital camera will do, including cellphone cameras. But for a controlled shoot, I recommend:

– 50mm lens
– Tripod (depending on conditions)
– Remote shutter release (if using tripod)
– Strong, diffuse lighting
– Polarizing filter (for shiny objects)
– Measuring tape
– Blue masking tape

ENVIRONMENT

Strong, very diffuse light is best. Harsh shadows can create problems.

A motionless, non-reflective, and varied background is good. The more random features there are in the background, the better the system can track points and triangulate.

A monochrome, uniform, featureless background can be problematic. Add clutter or tape marks to the background.

Repeating patterns on carpet or wallpaper are problematic.

SUBJECT

Light-colored, matte materials with some color variation are best. Dull, weathered stone is ideal.

Shiny, reflective surfaces are problematic. A polarizing filter may help reduce specularity in some cases. Dark, shiny bronze statues are very challenging.

EXPOSURE

Use as low an ISO setting as possible, to reduce noise. The software actually matches pixels to pixels from one photo to the next, so sensor noise creates a lot of problems.

Use as small an aperture as possible (high F-stop). The foreground and background both need to be in focus.

Use a tripod and remote shutter release for longer exposures.

If using a high F-stop is not possible, and the background cannot be kept in focus, at least try to keep the subject itself entirely in focus. Filling the frame with the subject can also improve results if a lower F-stop must be used.

SHOOTING

Take a measurement of a linear feature of the subject, or something in the background that will also be picked up in every shot. If feasible, place an object with a straight edge and known size in the scene, near or against the subject, and leave it there for the duration of the shoot. Don’t move it during the shoot. These will provide scale references.

Before shooting, find a distance from and path around the subject and a single zoom length that will allow you to take all your photos without adjusting the zoom. Avoid getting so close that you see big lensing/fish-eye or perspective and foreshortening distortions.

When shooting, don’t change the zoom ring at all. This is critical—you can move the entire camera closer or further away from the subject as needed, but don’t change the lens or exposure settings at all from shot to shot, as doing so will ruin the survey.

Try to have the subject fill the frame as much as possible.

Rotating the camera from shot to shot—from portrait to landscape or anything in between—is OK.

The light source cannot change or move relative to the subject at all from shot to shot. Don’t use a mobile flash. Any light source or flash needs to be fixed relative to the subject.

Take at least three laps around the subject, shooting from medium, high, then low angles, keeping the entire subject in frame. Then for additional close-up detail shots, take additional laps around the subject while aiming the camera so that the lens’ line of sight is perpendicular to the surface of the subject in the frame.

Take all photos in sequence—each shot should overlap with its neighboring shots. Don’t jump around the subject.

Every point on the subject must be in at least one series of at least three consecutive shots. The more series, from multiple angles, and the more consecutive shots per feature, the better the system can match points.

Make sure to take photos of features that are obscured by other features.

If you want to try different exposure settings, treat each shoot as a completely new photoshoot. Never mix settings between complete shoots. Take a photo of something between settings changes so that later you can see at a glance where the different exposure sets start and stop.

PROCESSING

Don’t edit the photos in any way. No cropping, re-sizing, levels adjusting, or masking.

When uploading, start with the shots that loop around the subject while keeping the subject completely in frame. Low, medium, and high angles. Then add any detail shots.

FUTURE-PROOFING

If practical, shoot in RAW, in addition to JPG. Some applications may be able to get better results with different JPG compressions of the original RAW files.

Shoot more photos than current software requires. You may get better results from set-to-set, or from different loops around the object within a set. More powerful applications may soon be able to get better results with more shots, so you may as well take as many as practical instead of going back and starting over a year later when more powerful software is available.

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LIFE-SIZE 3D PRINTED PORTRAIT

My client asked for a life-sized 3D printed portrait of his colleague, venture capitalist Brad Feld. Because the portrait was to be a surprise gift to Feld, there was no opportunity to scan the subject. The piece had to be modeled from photos of him culled from the web.

I proposed a bust, roughly from the shoulders up, with classical allusions, but I was vague about the details beyond that. The final design references the Artemision Bronze, Leighton’s An Athlete Wrestling with a Python and a few other sources.

I took a risk and bet that they’d like something other than a standard chairman-of-the-board type treatment. And what’s the point of having rock & roll hair if you aren’t going to do the whole heroic barbarian-warrior-champion-god thing when you have your life-size 3D printed portrait done?

This is the result.

This kind of remixing is just one small reason the world’s back catalog of public domain sculptural artwork should be digitized and published, freely, and without restriction.

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20140411 Life-size 3D Printed Portrait by Cosmo Wenman 3

20140411 Life-size 3D Printed Portrait by Cosmo Wenman 1

20140411 Life-size 3D Printed Portrait by Cosmo Wenman 2

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RESPONSE TO VENUS DE MILO

I’m tinkering with ideas and images for possible presentation at LACMA. This is a comparison of people’s response to the original Venus de Milo in the Louvre to their response to my 3D captured, 3D printed copy at the 2013 Paris 3D Printshow. The show was in the Louvre expo space, so my print was just a couple hundred feet away from the original.

I’m thinking that the fact that so many people are viewing the original through screens and taking photos undercuts the argument that there’s some essential, ineffable, supernatural awe involved in seeing the original, when really what people want is interaction, touch, control, and possession, all of which they get by mediating their experience with cell phones and cameras (for now).

November 22, 2013

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PERIKLES’ HELMET AT 2013 PARIS 3D PRINTSHOW

I’m working on ideas and images for a possible upcoming presentation to LACMA staff on 3D printing, 3D scanning, art, and museums. Here are photos of people at last week’s 3D Printshow in Paris responding to my 3D printed invention of Perikles’ helmet—a copy of an artifact that hasn’t been discovered and likely does not exist. Photos and touching allowed…

Novermber 22, 2013

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3D PRINTED/BRONZE-CAST MATISSE BOOTLEG AT THE LOUVRE

Because when’s the next time I’m going to be alone, after hours at the Louvre, with Vangelisesque muzak playing on the PA system, with my 3D captured, 3D printed bronze-cast bootleg of a Matisse? I found a buyer too…

From “3D Printed Lost PLA Bronze Casting and the Art of the Living Dead

(Why does YouTube suggest “Nightmare” as a tag for this video?)

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