Low-cost compact cameras: a medical application in CMT disease monitoring

Abstract

Recently, the price of low-cost compact cameras has fallen further, while in many brands and models the image pixel count has improved. These factors have increased their potential for photogrammetric measurement. In a recent event, there was a need for practitioners to have access to a photogrammetric technique for an application relating to Charcot–Marie–Tooth (CMT) disease. In this investigation, a low-cost multi-camera imaging system was developed for use by health-care practitioners. A case study of CMT disease of the upper limb was provided to demonstrate the suitability of the imaging system using these compact cameras. The objective of this paper is, therefore, to discuss the methodology and test results of an investigation into the suitability of these cameras for application in CMT disease. The imaging system was evaluated using four compact cameras, namely: Sony DSC-S700; Fujifilm A170;Canon A495; and Canon A490. Twenty-four calibrated slope distances were used for comparison of 3D measurement precisions with the different cameras used at two different object distances. The investigation showed that these compact cameras produced less precise measurements compared to the more expensive (above US$700)compact or SLR cameras. However, the current desired accuracy requirement for CMT disease applications is around 1 mm; hence these cameras are appropriate for the planned application.