Photogrammetry Introduction l Projects l Camera Systems l Aircraft l Image Interpretation Systems l The Digital Age
Our use of 5" format military reconnaissance cameras for marine mammal surveys began in 1979, with a KA45 camera that was modified and loaned to us by the US Navy. We used this camera system from a helicopter that was based aboard a chartered tuna purse seiner. The goal of our experiment was to determine the accuracy of counts of dolphins made from vertical aerial photographs.
The field test demonstrated that counts from vertical photographs did provide accurate estimates of true school size. We also found that the lengths of individual dolphins could be determined from these high-resolution images. As the program has evolved over the years we have moved through several former military cameras (KA62, KA51) to the KA76 cameras that we use today. Like all of our previous cameras, this former US Army camera has a forward image motion compensation system (FMC) that eliminates the loss in image resolution caused by the forward movement of the aircraft while the shutter is open.
We have collected images from several older aircraft (PBYs, AT11s) but now all of our missions are conducted from modern twin engine aircraft like the NOAA Twin Otter. Our standard configuration consists of two cameras mounted side by side. One camera is loaded with high resolution black and white film and fitted with a 6" (152 mm) lens. The adjacent camera uses color positive film and a wide angle 3" (76mm) lens. Typically, we use the black and white film images for measurements of the animals, and the color film for counting the number of individuals in large aggregations. As each camera fires, a data acquisition system records time, GPS position, and altitude.