Metric oblique image collection with UAVs

November 3, 2016  - By

Combining the best of two technologies for rapid situational awareness

Sometimes we get stuck looking in our own backyard for solutions, only to discover that those on the other side of the fence have been solving similar problems in a parallel effort. That was the case with metric oblique imagery when I joined Pictometry in 2007 and learned a little about the history of the players.

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Idan oblique imagery software ObliMapper.

Seems that a year after Pictometry inventors and patent holders, John Champa and Steve Schultz, filed their patent in 2002, another company, Idan, located in Israel, came up with the same solution. Idan filed for a U.S. patent in 2003, only to learn that they were too late.

Ironically, I learned from Joseph Freund, CEO and founder of Idan, that the Idan system was actually developed in 1996, but kept secret until declassified in 2003.

Although too late for Idan’s patent application, a mutual respect grew between the oblique pioneers. Over the years, Idan and Pictometry worked a number of joint efforts. Idan brought an especially unique perspective to technology, because for them, it was a matter of life and death. When you are a country the size of New Jersey and surrounded by countries literally dedicated to your destruction, your collective mind gets focused very sharply. That was exactly the case with the geospatial firm Idan, who worked very closely with the Israeli Defense Force (IDF) to protect their country.

Over the years, Pictometry became the leading collector of metric oblique imagery and focused on exploiting its vast image library for both public and private users. Today, after merging with Eagle View, Pictometry focuses on commercial application with remote roof measurement being its dominant business. Idan, however, never lost focus on its prime mission: defense. Idan continued to hone the technology and added new tools and hardware with the goal of building the most effective early-warning system with superb analysis capabilities.

A Robust Viewer

Idan developed and battlefield-tested tools to exploit oblique imagery. Its Oblivision viewer is different from other oblique image viewing systems in that it shows five synchronized views — an ortho view and four oblique views — with all views moving together as the operator shifts locations.

At first, this can be a bit overwhelming, with a lot of movement and much data to take in. But with use, the rich visual environment becomes second nature and provides the operator with an effective visualization environment.

In addition to multiple views, Oblivision provides measuring tools, both horizontal and vertical, GIS vector-data overlay, and analysis tools such as line-of-sight visibility, shadow and explosion vulnerability.

Here is an interactive example of a joint effort using Oblivision Online to view oblique imagery of Sacramento captured by Pictometry.

An interactive example of a joint effort using Oblivision Online to view oblique imagery of Sacramento captured by Pictometry.

An interactive example of a joint effort using Oblivision Online to view oblique imagery of Sacramento captured by Pictometry.

Improved Image Quality

Freund explained that Idan’s image quality has seen steady improvement through a joint project with Simplex using Idan’s own-built oblique camera system based on the 100-mp Phase One iXU camera. This has resulted in image resolutions exceeding 3 centimeters ground sample distance (GSD) from flight altitudes of 450 meters.

ObliMapper: The UAV link

A shortcoming of most oblique capture systems is that image capture is a complex and cumbersome process not suited for nimble response. The cameras and aircraft require significant preparation, on-station time and extensive post processing. The need for rapid image capture with oblique capabilities prompted Idan engineers to test options that take advantage of small, rapidly deployed UAVs.

Idan engineers developed a capture system capable of rapid focused area of interest image capture that fills the need: ObliMapper. Using compact georeferenced cameras mounted on COTS (commercial-off-the-shelf) UAVs, the ObliMapper system not only captures the imagery; the same system pre-plans and directs the flight of the UAV to optimize the entire capture process.

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The DJI Mavic UAV.

Simply stated, the work process can be summed up as follows:

  • Flight planning
    • The user selects the area of interest and identifies the camera being used.
    • The system then creates a route file and uploads it to the drone.
  • Image capture
    • The drone flies autonomously according to the flight plan.
    • The camera captures the imagery.
    • The images are downloaded to the user’s computer.
  • Processing
    • The system automatically processes the images and metadata.
  • Analyze
    • The user views the up-to-date oblique images from all directions with accurate measurements on the oblique images and overlaid GIS data, contour lines, slopes, visibility, etc.

Two YouTube videos provide an excellent overview of the system and process:

oblimapper-wNumerous enhancements of ObliMapper are being tested, including 3D model creation using Agisoft or Pix4D, image capture at night, and even the use of a swarm of UAVs to rapidly capture an area of interest in a single pass in hostile areas.

The images captured by the system have a positional accuracy of 5-15 meters, but post processing can result in accuracies in the 30-60 centimeter range.

Now that the Pictometry patents have expired, many companies are entering the oblique image market. I expect that improvements and new capabilities will follow regularly; however, from my view at this time, no one comes close to the vast oblique image library built by Pictometry (now over 4 Petabytes and 150,000,000 images) and no one seems to have the technical expertise that Idan has developed to exploit oblique imagery.

For more information, visit the following websites:

This article is tagged with and posted in GeoIntelligence Insider, Opinions
Art Kalinski

About the Author:

A career Naval Officer, Art Kalinski established the Navy’s first geographic information system (GIS) in the mid-1980s. Completing a post-graduate degree in GIS at the University of North Carolina, he was the Atlanta Regional Commission GIS Manager from 1993 to 2007. He pioneered the use of oblique imagery for public safety and participated in numerous disaster-response actions including GIS/imagery support of the National Guard during Hurricane Katrina; the Urban Area Security Initiative; a NIMS-based field exercise in Atlanta; and a fully manned hardware-equipped joint disaster response exercise in New York City. Kalinski retired early from ARC to join Pictometry International to direct military projects using oblique imagery, which led to him joining SPGlobal Inc. He has written articles for numerous geospatial publications, and authors a monthly column for the GeoIntelligence Insider e-newsletter aimed at federal GIS users.

1 Comment on "Metric oblique image collection with UAVs"

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  1. George says:

    Really nice article!!!