Aerial photo scanning!
Damn, what's next? Televisions that get programs from space? Phones you can carry in your pocket? Computers that can talk to each other?
Why, I'll bet that by 2013 we'll even have cars that fly, just like George Jetson's!
Showing posts with label aerial photography. Show all posts
Showing posts with label aerial photography. Show all posts
Thursday, September 19, 2013
It's New! It's Revolutionary! It's...
Damn, what's next? Televisions that get programs from space? Phones you can carry in your pocket? Computers that can talk to each other?
Why, I'll bet that by 2013 we'll even have cars that fly, just like George Jetson's!
Sunday, September 1, 2013
Thinking in 3D
This week at work, just for fun, I set up a stereoscope and slid some stereo photos underneath the mirrors. These photos are high resolution, large scale shots taken back in April when we had a new orthorectified aerial image of the airport developed. I asked the contractor to send me a stereo pair from the project that I could play around with. It's been years since I spent any time peering though the optics of a stereoscope and it was fun to look over the images and realize just how much a stereo view adds to one's ability to pick out details.
There was a time when analyzing stereo images was a critical skill in my field and other related fields. But with the rise of commercial satellite imagery, the slow demise of wet process aerial film cameras and the development of digital imagery analysis systems like ERDAS Imagine and ESRI's improved raster management routines in ArcGIS there has been less and less call for hard copy stereo image analysis. Software routines now handle most analysis tasks. Of course photogrammetrists still process, manage and analyze stereo imagery, but it's all done on high end digital systems these days. The fields that used to derive benefit from hard copy stereo imagery - topography, geology, forestry, hydrology, even the US military - all seem to have lost their institutional 'feel' for the usefulness of stereo imagery analysis.
The issue was brought home to me this week when I invited a small group of GIS professionals and Engineering staff (both licensed civil engineers and engineering technicians) to drop by my desk to have a look at these stereo photos. Most could not get the photos properly aligned underneath the stereoscope. Few recognized any real benefit from seeing the structures in stereo. Most thought it was just a cute parlor trick. That's a shame because the stereo photos permitted quick and easy identification of features that are not readily apparent in the same 2D images. Things like antenna masts and raised utility piping on the roofs of concourses, raised concrete pads and curbing in the aircraft gate areas and even small assemblies like receiver domes on the tops of aircraft fuselages stood out in clear detail when viewed in stereo.
.
So how does one use stereo photos for analysis? Check out this blog posting from a while back.
Conducting stereo analysis using hard copy photos should be much cheaper and easier these days. Years ago in the era of wet process film cameras making copies of stereo photos was time consuming and expensive. Someone had to pull a roll of film negatives, go into a darkroom and make prints one by one. With today's digital imagery systems all one has to do is download the image files from a server and print them out using relatively cheap but very high quality color ink jet printers. The images I received from our contractor were full resolution TIFF files, each about 1.4 gigabytes. I was able to subset just the areas I wanted to view and print them out at full resolution using only the image management software that comes with Windows 8. Fast and cheap!
Federal and state governments are sitting on a gold mine of historical stereo aerial photos. The Federal government (USGS, USC&GS, Soil Conservation Service, Department of Agriculture, Tennessee Valley Authority, Army Corps of Engineers, etc.) started using stereo aerial photography for mapping as early as the mid-1920s and over the course of the next 90 years proceeded to photograph virtually all of the United States in stereo. Stereo aerial photography was the foundation of all of our topographic mapping activities through most of the 20th century and it remains so today. Much of this photography is still held in individual agency archives or has been turned over to the National Archives. I'd love to see the National Archives digitize and post nationally significant stereo pairs of images online for downloading and viewing. Places like the Grand Canyon, Yosemite and Yellowstone or historic events like the Mount St. Helens post-eruption photos or levee breaches along the Mississippi River during the spring floods. Even historic shots of our cities and suburbs that will help students understand how topography impacts issues like urban sprawl.
Humans view and relate to their world in three dimensions. It's a shame that today we are relegated to investigating it via boring 2D computer displays. I think it's time to bring back 3D image analysis!
There was a time when analyzing stereo images was a critical skill in my field and other related fields. But with the rise of commercial satellite imagery, the slow demise of wet process aerial film cameras and the development of digital imagery analysis systems like ERDAS Imagine and ESRI's improved raster management routines in ArcGIS there has been less and less call for hard copy stereo image analysis. Software routines now handle most analysis tasks. Of course photogrammetrists still process, manage and analyze stereo imagery, but it's all done on high end digital systems these days. The fields that used to derive benefit from hard copy stereo imagery - topography, geology, forestry, hydrology, even the US military - all seem to have lost their institutional 'feel' for the usefulness of stereo imagery analysis.
The issue was brought home to me this week when I invited a small group of GIS professionals and Engineering staff (both licensed civil engineers and engineering technicians) to drop by my desk to have a look at these stereo photos. Most could not get the photos properly aligned underneath the stereoscope. Few recognized any real benefit from seeing the structures in stereo. Most thought it was just a cute parlor trick. That's a shame because the stereo photos permitted quick and easy identification of features that are not readily apparent in the same 2D images. Things like antenna masts and raised utility piping on the roofs of concourses, raised concrete pads and curbing in the aircraft gate areas and even small assemblies like receiver domes on the tops of aircraft fuselages stood out in clear detail when viewed in stereo.
.
So how does one use stereo photos for analysis? Check out this blog posting from a while back.
Conducting stereo analysis using hard copy photos should be much cheaper and easier these days. Years ago in the era of wet process film cameras making copies of stereo photos was time consuming and expensive. Someone had to pull a roll of film negatives, go into a darkroom and make prints one by one. With today's digital imagery systems all one has to do is download the image files from a server and print them out using relatively cheap but very high quality color ink jet printers. The images I received from our contractor were full resolution TIFF files, each about 1.4 gigabytes. I was able to subset just the areas I wanted to view and print them out at full resolution using only the image management software that comes with Windows 8. Fast and cheap!
Federal and state governments are sitting on a gold mine of historical stereo aerial photos. The Federal government (USGS, USC&GS, Soil Conservation Service, Department of Agriculture, Tennessee Valley Authority, Army Corps of Engineers, etc.) started using stereo aerial photography for mapping as early as the mid-1920s and over the course of the next 90 years proceeded to photograph virtually all of the United States in stereo. Stereo aerial photography was the foundation of all of our topographic mapping activities through most of the 20th century and it remains so today. Much of this photography is still held in individual agency archives or has been turned over to the National Archives. I'd love to see the National Archives digitize and post nationally significant stereo pairs of images online for downloading and viewing. Places like the Grand Canyon, Yosemite and Yellowstone or historic events like the Mount St. Helens post-eruption photos or levee breaches along the Mississippi River during the spring floods. Even historic shots of our cities and suburbs that will help students understand how topography impacts issues like urban sprawl.
Humans view and relate to their world in three dimensions. It's a shame that today we are relegated to investigating it via boring 2D computer displays. I think it's time to bring back 3D image analysis!
Friday, April 22, 2011
Terrain Analysis
Last week I stumbled across this gem on YouTube -
It is a slightly dry film put out by the US Geological Survey in 1955 showing the modern (for the time) processes developed for natural resource analysis using aerial photography.
The guy narrating it sounds about as excited by his work as a dry goods salesman discussing the newest laundry soap. Zzzzzzzzz...
But once past the dry narration I was interested by the methods demonstrated for geological, hydrological, soils and forestry analysis. What struck me was that these were the precise methods we were taught at the Defense Mapping School as late as the early 1990s. These photo analysis processes formed the basis for what we called Terrain Analysis, and in fact my job title for much of my Army career was Terrain Analysis Technician (MOS 215D).
This film approaches each type of analysis as an independent process - an end in itself. We carried the analysis to the next level and merged the output from each of these four disciplines, mixed in some military-specific data like vehicle off-road capabilities, tossed in some road network analysis, some urban analysis and a pinch of weapon systems analysis and produced what we called a military terrain analysis. Our products were usually delivered in the form of map overlays known as a combined obstacle study. The process was very labor intensive and usually tightly focused on specific geographic areas like the Fulda Gap in Germany or the Koksan Bowl in Korea, natural movement corridors that had been used by armies for centuries.
Soldiers going into the Army's Terrain Analysis field received extensive training in field identification methods like geological and soils analysis, hydrological analysis and route engineering studies. They were taught to observe, test and measure in the field using a variety of hands-on methods. Next they moved to the classroom and were taught advanced aerial photo analysis techniques and applied their field knowledge to what they saw in the photos. It was hours and hours of peering at photos through stereoscopes, analyzing texture, tone and pattens to develop a detailed analysis of the terrain and it's impacts on military operations.
Computers have taken on the burden of much of this analysis, and today you can feed a digital image into a sophisticated image analysis package like ERDAS Imagine and have it analyze huge swaths of territory in a small fraction of the time it took using the old manual methods shown in the film. Still, it is fun to see how things were done in the good old days when men were men, hardhats were made out of aluminum and the science of aerial photo analysis found new applications in the civilian and military worlds.
It is a slightly dry film put out by the US Geological Survey in 1955 showing the modern (for the time) processes developed for natural resource analysis using aerial photography.
The guy narrating it sounds about as excited by his work as a dry goods salesman discussing the newest laundry soap. Zzzzzzzzz...
But once past the dry narration I was interested by the methods demonstrated for geological, hydrological, soils and forestry analysis. What struck me was that these were the precise methods we were taught at the Defense Mapping School as late as the early 1990s. These photo analysis processes formed the basis for what we called Terrain Analysis, and in fact my job title for much of my Army career was Terrain Analysis Technician (MOS 215D).
This film approaches each type of analysis as an independent process - an end in itself. We carried the analysis to the next level and merged the output from each of these four disciplines, mixed in some military-specific data like vehicle off-road capabilities, tossed in some road network analysis, some urban analysis and a pinch of weapon systems analysis and produced what we called a military terrain analysis. Our products were usually delivered in the form of map overlays known as a combined obstacle study. The process was very labor intensive and usually tightly focused on specific geographic areas like the Fulda Gap in Germany or the Koksan Bowl in Korea, natural movement corridors that had been used by armies for centuries.
Soldiers going into the Army's Terrain Analysis field received extensive training in field identification methods like geological and soils analysis, hydrological analysis and route engineering studies. They were taught to observe, test and measure in the field using a variety of hands-on methods. Next they moved to the classroom and were taught advanced aerial photo analysis techniques and applied their field knowledge to what they saw in the photos. It was hours and hours of peering at photos through stereoscopes, analyzing texture, tone and pattens to develop a detailed analysis of the terrain and it's impacts on military operations.
Computers have taken on the burden of much of this analysis, and today you can feed a digital image into a sophisticated image analysis package like ERDAS Imagine and have it analyze huge swaths of territory in a small fraction of the time it took using the old manual methods shown in the film. Still, it is fun to see how things were done in the good old days when men were men, hardhats were made out of aluminum and the science of aerial photo analysis found new applications in the civilian and military worlds.
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