Three dimensional surface reconstruction of lower limb prosthetic model using infrared sensor array

Abstract

This thesis addresses the development of a shape detector device using infrared sensor to reconstruct a three-dimensional image of an object. The threedimension image is produced based on the object surface using image processing technique. Conventionally, infrared sensors are used for detection of an obstacle and distance measurement to avoid collisions. However, it is not common to use infrared sensors to measure the size of an object. Hence, this research aims to investigate the feasibility of infrared sensors in measuring the object dimension for three-dimension image reconstruction. Experiments were executed to study the minimum distance range utilising GP2D120 infrared sensor. From the experiment, the distance between the sensor and object surface should be more than 5 cm. The scanning device consists of the infrared sensor array was placed in a black box with the object in the center. The scanning process required the object to turn 360 ° clockwise in an xy plane and the resolution for z-axis is 2 mm, in order to obtain data for the image reconstruction. Reference polygon shape models with various dimensions were used as scanning objects in the experiments. The device scans object diameter every 2 mm in thickness, 100 mm in height, and the total time required to collect data for each layer is 60 seconds. The reconstructed object accuracy is above 80 % based on the comparison between a solid and printed model dimension. Four different lower limb prosthetic models with different shapes were used as the object in the scanning experiments. The experimental findings show that the prosthetic shapes reconstructed with an average accuracy of 97 %. This system shows good reproducibility where the collected data using the infrared sensor device need further improvement so that it can be applied in medical field for orthotics and prosthetics purpose.