Abstract

The objective of this project is to determine the area of a skin lesion from a photo and calculate the lesion diameter to help automatically diagnose melanoma. The American Cancer Society recognizes the guidelines of asymmetry, border irregularity, color irregularity and diameter as markers for possible melanomas; lesions with a diameter greater than 6 mm may need to be examined by a doctor. Because of variable distances between the phone camera and the lesion in question, the size of the lesion changes in comparison to the picture. Two methods have been developed for determining the area of a lesion within a close proximity to the camera. The reference-based method uses a coin of known size as a reference and utilizes the automatic image segmentation and recognition capabilities of OpenCV on Android to calculate the area of a lesion. The focus-distance-based method uses the focus distance returned by the phone camera to determine the distance from the camera to the lesion. Then from the size of the lesion image and the corresponding distance, the actual size of a lesion can be calculated. The two methods were tested through experiments with various objects at different distances from 10 to 15 cm. Experimental results show that the reference-based method produces diameter estimations with errors typically less than 3% and an average error of 0.96%. The errors of the focus-distance-based method are less than 13% with an average error of less than 5%. Though more accurate, the reference-based method requires the user to have a coin with them when they use the app. Both methods are successful and are being incorporated into our automatic melanoma detection app on Android smartphones.