Photographic Intersection - a brief overview  

Photographic Intersection - a brief overview

The low cost method for accurately measuring 3D points.

     
Photographic Intersection - development  

Photographic Intersection - how I developed my ideas

A brief history of the events and ideas that developed into my views on Photographic Intersection.

   

 

Photographic Intersection - the technicalities  

Photographic Intersection - the technicalities

The technical details that support Photographic Intersection.

     
The Use of Spherical (360) Panoramas for Photogrammetry  

The Use of Spherical (360) Panoramas for Photogrammetry

Spherical Panorama projections are suitable for the extraction of measurements to compute the 3D co-ordinates for points from two or more panoramas.  The mathematics involved is much more straight forward than that required for using photographs for Stereo Photogrammetry and Photographic Intersection.  Horizontal and Vertical angles are easily measured in an Equirectangular projection to provide the same data as if a theodolite was used at the same location.

     
Accuracy for Intersection  

Accuracy for Intersection

The accuracy for a point measured using an Intersection method is determined by three inter-related factors:
the separation of the Stations (Base Line),
the Angle of Intersection and
the Precision of the Angular Measurements.

     
Accuracy Evaluation for Measurements from 360 Panoramas  

Practical Evaluation of Accuracy for Measurements from Panoramas

Practical exercises to evaluate the accuracy of measurements from 360 Panoramas.

     
Spherical Panoramas for Photogrammetry  

Spherical Panoramas for Photogrammetry

 

3D measurement techniques are readily available, but low cost solutions are needed for applications where only a small quantity of data is required.  Measurements can be made from Spherical Panoramas using available techniques, but these are time consuming, error prone and laborious, so this is an appeal to those with skills in software development in the fields of digital imaging and the mathematics to compute intersecting rays in space to provide a viable and cost effective solution.

     
Using 360 iSTAR Panoramas to add Detail to an HDS Point Cloud  

Using 360 iSTAR Panoramas to add Detail to an HDS Point Cloud

Real world colour can be added to the points in a Point Cloud from co-centric 360 (spherical) panoramas and some users have found that it is also beneficial to take additional 360 panoramas.  This task takes this one stage further and uses 360 panoramas to add detail to a survey initially made with an HDS Scanner.

     
Image Assisted Surveying from Leica Geosystems  

Image Assisted Surveying

In October 2010, Leica Geosystems introduced Image Assisted Surveying on their Total Stations with the introduction of the Leica Viva Imaging Total Stations.  This product greatly enhances the functionality, ease of use and productivity of the on-board applications and provides useful features for Photogrammetric and Photographic Intersection surveying and mapping techniques.

     
360 Panoramic Optic for Photographic Intersection  

360 Panoramic Optic for Photographic Intersection

A Conical Mirror or Prism to provide a full 360 panorama for surveying and mapping.

     
Panoramic Photography As A Survey Tool

 

Panoramic Photography As A Survey Tool

 

A paper describing the development of an optical device for use in detail surveying, which enables panoramic photographs to be taken using conventional cameras and lens systems, and suggests how such a device can be used as a tool in some survey disciplines.

Author:  Hugh Anderson,  1st August 1978

     
Determining the Nodal Point of a Lens  

Determining the Nodal Point of a Lens

For a lens to be used effectively for Photographic Intersection the location of the Front Nodal Point must be accurately determined.

     
The case for the Nodal Point   The Nodal Point

The case for the Nodal Point and usage of the term..

     
Light Line for measuring Tunnels  

Photographic Intersection by Light Line for measuring Tunnels

Images of the FITS and  HITS units being used to measure tunnel profiles.  A Light Line is projected onto the tunnel surface defining a plane through the tunnel at the particular chainage require.  This is photographed and digitised to produce an accurate profile of the tunnel.  A 1000 metres of tunnel could be measure every 10 metres in a single nights possession using this technique.

     
Patent No. 1493188  

Patent No. 1493188

Optic for instantaneously photographing an horizon of 360.

     
Optic for instantaneously photographing an horizon of 360  

Optic for instantaneously photographing an horizon of 360

Patent specification GB1493188, 22nd April 1975.

     
Method and apparatus for photographic tunnel sectioning - Patent  

Method and apparatus for photographic tunnel sectioning

European patent application.

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