Fryer, John 
  
     
Figures 9 and 10. Typical Scene of Bank Robbers with Guns, Close-up of Shotgun. 
The anharmonic ratio was applied to measurements made on the guns, which had been tendered as exhibits to the court 
case, and on frames printed from the video images. The differences in values obtained for the anharmonic ratios were 
usually less than 1%. Given the relatively coarse nature of the measurements (paper prints of the video scenes, 
magnifying glass, plastic ruler and a tape measure), this was considered to be strong evidence that the weapons 
exhibited in court and those measured off the video were identical. After six hours of presentation of evidence, cross- 
examination and re-examination, both with and without the presence of the jury, all the photogrammetric evidence was 
accepted. 
7 CONCLUSION 
Photogrammetric principles applied to the imagery captured by surveillance cameras can provide strong evidence which 
is acceptable in courts of criminal law. The photogrammetrist must be prepared to be flexible in his methods and 
presentation of results. Conventional mathematical techniques of solution, such as iterative least squares applied to 
linearised collinearity equations, can be difficult to concisely explain to a jury of lay-persons. Physical models must be 
created and simple diagrams prepared to convince the jury that they can comprehend the scientific logic and 
calculations. 
The concept that light travels in straight lines and that a piece of string can replicate a ray of light is an example of the 
type of simple modeling which the photogrammetrist must exploit. Estimates of error must also be capable of 
demonstrable substantiation, not just the submission to the court of the last page of a printout of a computer program. 
A photogrammetrist in court must be thoroughly conversant with his subject and understand the physical realities of 
whatever mathematics he uses. The subtleties of photogrammetry, the source of much pleasure to those working in this 
profession, should be avoided in the court-room. These finer points of photogrammetry will only provide the opposing 
attorney with material which can be used to confuse a jury and thereby undermine the photogrammetric evidence. Keep 
it simple! 
POSTSCRIPT 
It must be stressed that the photogrammetric measurements and height determinations were not the sole items of 
evidence provided in the two court cases referenced in this paper. In one case there were 45, and in the other 72, 
persons who tendered different forms of evidence to the juries. Many belonged to various police departments who had 
been involved with covert surveillance of suspects, phone-tapping and other information gathering tasks. In some ways 
this made the photogrammetric evidence more valuable as juries can sometimes be suspicious when all the evidence is 
provided by the police. Finally, after 3 weeks of trial in one case and 6 weeks in the other, the juries returned guilty 
verdicts. The judges decided upon sentences of 12 and 18 years, with 10 and 14 year non-parole periods respectively 
(Regina v. Hughes, 1999 and Regina v. Gallagher, 1999), 
REFERENCES 
Regina v. Gallagher, 1999, District Court at Sydney, Kinchington QC DCI. 
Regina v. Hughes, 1999, District Court at Newcastle, Armitage QC DCJ. 
Thompson, E.H., 1962. Photogrammetry. The Royal Engineers Journal 76(4): 432-444 and re-printed in 
Photogrammetry and Surveying, A Selection of Papers by E.H. Thompson, 1910-1976, Photogrammetric Society, 
London, 1977, 242-254. 
Wolf, P.R., 1983 , Elements of Photogrammetry, Mc. Graw-Hill, 628pp. 
  
252 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000. 
  
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