Week 4

Week 4 Overview (August 3rd, 2012)

This week consisted solely of photogrammetry. Georgia O’Keeffe’s home is quite large and we still have a lot of images to capture of the interior; however, on August 1st we finished capturing the entire exterior of the house, not including the courtyard and studio. Every time we are on site, the process goes much smoother and quicker. For the entire perimeter of the house we have taken over 1200 photographs that need to be processed.

The exterior of the front side of Georgia O’Keeffe’s home.

Joey and Greg capture the outside of the kitchen.

Before this week, we would place two rows of dennison dots all 4 feet apart. We figured this would allow for accurate scale within the mesh. It would also help the software with finding overlapping points on the highly textured wall. This week we reduced the number of rows to one, all the same distance from the ground, and 4 feet apart.  This proved sufficient for the mesh to be able to create accurate measurements. It saved a lot of time too!

Two rows of dennison dots.

One row of dennison dots.

We began processing our images and received the highest quality mesh to date! We did several tests on what kind of image quality is necessary for our own documentation. Using Photoshop CS6 we exported all the jpegs at 10 quality. Each image was around 10-12MB. We attempted to export at 8 quality but the images were only 3-5MB and the point cloud was too scarce. We processed the images at 10 quality, and in PhotoScan we made the Geometry in medium quality. Here are the comparisons:

JPEG: Photoshop exported 10 quality
PhotoScan Geometry: Medium quality
Number of Photos: 38 pictures
Time to Process: 1 Hour

JPEG: Photoshop exported 10 quality
PhotoScan Geometry: High quality
Number of Photos: 38 pictures
Time to Process: 7 Hours

There is a significant processing difference in adjusting the geometry quality. At medium it took an hour and at high it took seven hours. We also compiled a mesh of 84 images at high and left it overnight. It was finished by the morning but we don’t know exactly how long processing took for that batch. Comparing the textured meshes in PhotoScan showed some difference. The medium was more pixelated than the high as you zoomed in. Ultra quality would take several days to process so we haven’t tested that yet.

Mesh with a medium quality geometry

Mesh with a high quality geometry.

It would be of great help if we could create a queue to process in PhotoScan. We could then leave several “chunks” to process over a weekend and clean the meshes up during the week. We will have to request this feature from Agisoft!

Here are some of the 3D renderings we got of the front of the house!

The wireframe PhotoScan compiled.

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