COMPARATIVE TuSTS OF THZ ACCURACY OT PANCHROMATIC, INFRA-RED 
AD COLOUR PICTURES FROM Ti AIR FOR PHOTOGRAZHETRIC PURPOSZSS 
  
DL. Ottoson 
Stockholm 70 
The so called y-parallax method to determine the radial 
distortion of a lens from aerial »hotozraphs, which is de- 
scribed in [1] and [2], has been used for comparative tests 
of the geometrical properties of panchromatic, infra-red and 
colour photosraphs. 
The three pairs of stereoscopic pictures examined were 
photographed by the Swedish Geographical Survey Office over 
the same piece of ground. They were aporoximately vertical 
photographs with normal overlapping. An Aviogon lens was 
used for the panchromatic photographs, an Infragon lens for 
the infra-red ones, and an Aviotar lens for the colour photo- 
graphs (Kodak jktachromo). The flying altitude for the two 
first pairs of photographs was about 3.900 meters and for the 
colour photozravhs about 1000 meters. 
The three pairs of stereoscopic pictures were oriented 
in the Autograrh A7 at the Photogranmetric Division of the 
Royal Institute of Technology. The original film of the 
colour photogra hs was used, while contact diapositive plates 
were made of the pictures in black and white. The relative 
orientation was executed roughly empirically, after which the 
y-parallaxes were measured in © points and the numerical ori- 
ontation was carried out [5]. No absolute orientation was 
made, 
From repeated series of y-p2rallax measurements in the 
rientation points the following standard errors of the mea- 
“urements wore computed from wellknown formulas: