|
||||||||||
The development of the 360° Panoramic Optic for Photographic Intersection The productivity of using photography as a measurement tool really manifested itself in 1973 when I was required to map Annesley Hall (north of Nottingham) in its entirety at a scale of 1:50. The building was a myriad of rooms. There was a cellar and four floors with mezzanine floors between and the roof space and roofscape to map. The nature of the building meant that the rooms were not rectangular and the walls were not parallel. Also, there were many hidden spaces including priest holes and a completely sealed off room above the main entrance. It was also a requirement to map the facades and for this Close Range Photogrammetry using the recently acquired Wild P32 camera proved to be an efficient and productive method. To tie the rooms together I used a technique which was considered controversial at the time. I traversed through the building using a Wild T2 and Wild DI10, but most of the measurements were made by tape and using tools that I had to specially develop for the task. As the use of photography proved such an efficient method for mapping the external walls, perhaps there was a solution involving photography to make the task of measuring each and every room less labour intensive and laborious.
The principle
was there and this lead to my invention of the conical mirror or
conical prism. This provided a distorted image, but one in which
all the points of detail were radial from the centre of the image.
The images produced from such a device could be used in the same
In the 19070s the personal computer was science fiction, but with today's technology the circular images could be digitised and the points calculated on the computer. However, the need for these specialised images has been nullified by the power the computer as the same results can be achieved with 'conventional' images if we know their location and orientation in space, but I still feel that being able to capture a full 360° panoramic image in an instant has its advantages. If you are interested in Photographic Intersection, or wish to comment on the subject, please contact me on PhotoIntersect@AOL.com.
|
||||||||||
|
|
||||||||||
My
first thoughts were to use a fish-eye on camera on its back so that
the image surface (film plane) was horizontal. Such lenses produce
tremendous distortions in the image, but with the film plane
horizontal, all the rays from the centre point to features around
the rim of the image are true. With the camera at a know location
all the angles to the points of interest would be the same as if
measured with a theodolite. At that time the plotting of detail
measured by theodolite was done by placing a large protractor under
the plotting trace at the point representing the Theodolites
location and orientating it to another identifiable point. The
image from the fish-eye lens could be used in the same way. The
intersection of rays from different images taken at different
locations would plot the points of interest in exactly the same way
as in Plane Table surveying. Using a photographic solution
meant that all the detail on the room was capture at one time so
that if additional detail needed to be plotted, this could be done
without having to revisit the site. However, this idea had one
major drawback, all the information was compressing into a narrow
band around the perimeter of the image making it very difficult to
interpret. Also, getting the exposure right, especially
outdoors, can be tricky.
way
as those from a fish-eye lens, but it is also possible to calibrate
the image so that the radial distance from the centre could be used
to calculate the vertical angle above and below the horizon to
calculate heights. I was granted a
