AnthSpace@PSU: Photography Archives

Super Simple KAP and PhotoScan Example

By Nathan M. Craig on April 7, 2011 6:56 PM | 0 Comments | 1 TrackBack

This post illustrates the use of a simple KAP rig in conjunction with structure from motion photogrammetry to generate a dense surface model of a threatened archaeological site.

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Pukara Sunken Plaza 3D Model

By Nathan M. Craig on April 1, 2011 5:21 PM | 0 Comments | 0 TrackBacks

This post displays a 3D model of one of the sunken plazas from the site of Pukara, Puno, Peru. During July, 2009 I was visiting excavations by my colleague Liz Klarich (Smith) and using the opportunity to practice photogrammetry on large architecture that had been previously reconstructed. The sunken plaza shown was excavated and reconstructed in the 1970's under Plan COPESCO. In the past, I had collaborated with Liz on aspects of mapping the site of Pukara. The sunken plaza has always captured my interest. This model was the first large architectural feature I attempted to record using photogrammetry. The uneven surface of the ichu grass presented some challenges, but these were overcome by aggressive decimation of the surface. The model was generated with PhotoScan and is displayed on this website as a PDF. The file is large, it may take a moment to download, and may strain computers with low RAM.

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Make a DEM from a Photosynth Point Cloud

By Nathan M. Craig on January 17, 2011 8:52 PM | 0 Comments | 0 TrackBacks

Archaeologist and elite low elevation aerial photographer Mark Willis recently posted a wonderful and informative tutorial on how to create a DEM from a Photosynth Point cloud. The photographs used in his tutorial example were captured by KAP, and the site is Palmitopamba in Ecuador. KAP is probably the most inexpensive LEAP technique, so this was a great proof of concept. Mark also strove to use free and open source applications through the entire work flow. Again, this low cost approach means that the methods should be available to nearly any researcher. One of the stages in Mark's procedures draws inspiration from an earlier post on this site regarding the transformation of structure from motion point clouds to real world coordinates. Mark simplified and clarified the process. This was exciting for me because it was Mark's earlier work with photosynth that stimulated my interests in KAP and structure from motion photogrammetry.

Blaise Aguera y Arcas demos augmented-reality maps

By Nathan M. Craig on May 4, 2010 6:29 PM | 0 Comments | 0 TrackBacks

Camera Remote Controllers for aerial photography

By Nathan M. Craig on April 13, 2010 7:22 PM | 0 Comments | 0 TrackBacks

Low altitude small format aerial photography requires some kind of remote shutter release. I'm a user of Canon's, and the G11 is presently the camera I use for aerial work. I am presently aware of three camera controllers that permit shutter and zoom. As I become aware of additional systems, I'll include them here.

The URBI R/C interface with zoom works with a suite of cameras, and even allows zoom with some Canon Powershot cameras.

The gentLED family of products is another possible solution for controlling a camera remotely. I have a gentLED Focus on my DuneCam KAP rig. I like the fact that the gentLED products are so light weight (9g). It looks like the gentLED CHDK2 has zoom capabilities as well, but I've yet to try it out. Both the URBI and the gentLED CHDK2 connect to an r/c receiver.

CAMremote works with several cameras including my G11. CAMremote has a wide range of functions that includes shutter, zoom, shutter speed, and aperture.

Geotagged Photo Survey to GIS point data

By Nathan M. Craig on April 9, 2010 4:51 PM | 0 Comments | 0 TrackBacks

This post describes the process of recording surface artifacts by means of geotagged and hierarchically coded photographs.

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Panorama of Slope at the Fortress of Visquira

By Nathan M. Craig on January 17, 2010 7:34 PM | 0 Comments | 0 TrackBacks

A large and steep slope with many fragments of wall. This version of the image only has a single annotation to give some sense of the nature of the constructions on the slope. Look for the two human figures (Margaret Brown Vega and Albino Pilco Quispe) that are located to the right hand side of the image. When exploring the image, be sure to click on the full window button on the far right.

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1906 San Francisco Earthquake by kite

By Nathan M. Craig on January 16, 2010 9:41 PM | 0 Comments | 0 TrackBacks

The photograph displayed in this famous and historic panorama was taken by George Lawrence shortly following the 1906 San Francisco earthquake. The photograph is entitled, "Photograph of San Francisco in ruins from Lawrence Captive Airship, 2000 feet above San Francisco Bay overlooking water front. Sunset over Golden Gate." The image is composed of multiple frames. The camera used to take the photographs weighed 46 pounds, it was hoisted 800ft into the air, and the shutter was triggered with an electrical impulse generated by an old style telephone magnet. A diagram of the rig can be found on this page. Some images of the camera and Lawrence sending it into the air can be found here. Several groups have attempted to replicate the photograph. One group did so using a replica of the camera, but the shot was taken from a helicopter. Another group, employed a kite but used modern cameras. The image that is displayed in this post is a digital copy of an 18 x 48" gelatin silver print that is stored at the Library of Congress. Here in this post, for display I have piped that image through the Seadragon plugin. Another version can be found at the USGS.

PhotoSynth Projects Feed

By Nathan M. Craig on December 26, 2009 2:10 PM | 0 Comments | 0 TrackBacks

I have started using PhotoSynth to generate dense point clouds to map archaeological sites. This post contains the RSS feed of the synths that I am creating. A future post will document the processes that I am using to generate the point clouds.

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Stereo Pair Photographs to ArcMap Digital Elevation Model

By Nathan M. Craig on October 24, 2009 12:00 AM | 0 Comments | 0 TrackBacks

In archaeology it is often useful to represent a surface as a digital elevation model (DEM). With just about any data collection process, there is a tradeoff between the extent of the coverage and the amount of detail that is captured within this coverage. Greater detail takes more time to collect, and smaller spaces can be characterized.

Fieldworkers create DEMs by means of a total station, and this is frequently an efficient method of generating data on surface undulations. However, even with a fast total station it can be extremely time consuming to generate high resolution surface models. Laser scanners may be a useful solution, but these instruments are expensive. Stereo pair photographs can provide a lower cost solution to generating high resolution surface models.

In this post, I describe a workflow that involves processing stereo photographs of a surface to generate a high resolution (50mm) digital elevation model of a space that is roughly 2x4m. The procedure entails generating a dense surface model, or point cloud, in PhotoModeler Scanner. This point cloud is saved as a text file, converted to an Excel spreadsheet, and imported into ArcMap where a DEM is generated.

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Heart Rate and GPS

By Nathan M. Craig on July 22, 2009 3:39 PM | 0 Comments | 0 TrackBacks

I wanted a device that would serve two simultaneous purposes 1) track caloric effort as I move across space and 2) geocode photographs. Neither of these purposes requires high accuracy GPS, but these tasks do require a small GPS device. The Garmin Forerunner 405CX seems like a perfect device.

Canon EF 20mm f/2.8 lens specs

By Nathan M. Craig on July 9, 2009 8:27 AM | 0 Comments | 0 TrackBacks

Panoramic Photography Lens Database

Full frame=20mm, HFOV: 84° | VFOV: 62° | DFOV: 94°
1.3x=26mm, HFOV: 69° | VFOV: 50° | DFOV: 80°
1.6x=32mm, HFOV: 59° | VFOV: 41° | DFOV: 68°

Min. shots (full frame): N, 8 images every 45° at -60° pitch, 8 images every 45° at 0° pitch, 8 images every 45° at +60° pitch, Z
Min. shots (1.3x): N, 9 images every 40° at -50° pitch, 9 images every 40° at 0° pitch, 9 images every 40° at +50° pitch, Z
Min. shots (1.6x): N, 10 images every 36° at -45° pitch, 10 images every 36° at 0° pitch, 10 images every 36° at +45° pitch, Z Discuss this lens in our forum.

Geotagging and Photographic Mapping Software

By Nathan M. Craig on April 12, 2009 8:36 PM | 0 Comments | 0 TrackBacks

Image geotagging is a wonderful way to organize photographs spatially. The following post details some programs that will perform this task.

At present my two favorite geotagging programs are RoboGeo (ca. $30) and GeoSetter (FREE).

RoboGeo
Though it costs money, RoboGeo performs some fantastic functions that are not offered by many geotagging programs. Among the features that I like are:

Time stamp images
Geocode RAW (.CR5) files.
Export to KML, KMZ, Google Maps
Export ESRI shapefile. (Note, I'll be writing a post on this at a later date. The ability to export a geocoded photograph to a shapefile is a very powerful GIS data collection tool).
Export to Autocad DXF
Upload to Flickr and Yahoo Maps
Associate Dictation files with individual photos. (This is very handy for note taking in the field).

In another post, I describe a workaround for converting Trimble .SSF data into a format that RoboGeo (and other widely used geotagging programs) can use. Otherwise without Trimble's expensive software, SSF can be hard to use for geotagging.

GeoSetter
Free and powerful, GeoSetter is a GUI frontend for ExifTool--the mother of all image metadata editing programs. Unlike many free geotagging tools, GeoSetter will process RAW (.CR5) files. In my opinion, if you want to get started with geotagging this is the program to use.

GPS-Photo Link: GIS Pro Series
A somewhat expensive geotagging and photographic mapping software. It appears to also work with a laser rangefinder. Here is some information from their website:

• Users will now be able to indicate the direction they were facing when they took the photo.
GPS-Photo Link will automatically include directional information from a GPS's digital compass or the Ricoh camera's memo fields.
• A wedge indicating the Ricoh camera's field of view can be displayed as a shape file so users will know what is included in the picture when looking at the map.
• GPS-Photo Link now supports high resolution color photography from the USGS,
making your background maps more detailed and easier to read.
• USB capability allows the use of GPS receivers on PC's without a serial port hook-up.
• There are also changes to the ArcView Ricoh plug-in included with GPS-Photo
Link. The new version will output Personal GeoDatabases along with shape files
• Waypoint comments entered in the GPS can now be used as the default file
names for photos making it easier to find specific photos.
• Audio captured with a photo will be available to play as you enter attribute data

The following are a couple of GPS units that are used with a camera for geotagging. I do not use one of these units, I use a Garmin Forerunner 405cx. The advantages are that the unit is a wrist watch and it also has a heart rate monitor. The disadvantage is that the 405cx will only run for eight hours. During fieldwork I frequently have battery problems. Another disadvantage is that the 405cx does not output digital compass information.

GlobalSat BT-359 review

Qstarz BT Q1300 review

ATP PhotoFinder Mini review and another and yet one more and still another.

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