Lie detection on pupil size by back propagation neural network

A pupillometry is a device that measures diameter of pupil. Measuring diameter can be done for different reasons. However, if person is not fixed to the pupillometry, diameter value could vary depending on distance between subject and device. To overcome this problem radius of iris was taken as reference to pupil as output will be ratio of pupil diameter to iris diameter. In this paper one of cues of deception, pupil dilation was studied, the dilated and non-dilated iris images were image pre-processed and segmentation of pupil and iris was achieved. Images were chosen from MMU Iris database and images with big pupils are assumed to be dilated pupils that are indication of lying and small ones were assumed to be neutral. After pre-processing that follows segmentation of pupil and iris, pupil to iris ratios as 60 samples of 1 element with 10 hidden neurons were fed into neural network for classification by neural network pattern recognition tool. All images were correctly classified.