Compression of corneal images for use in telemedicine systems

JPEG (Joint Photographic Experts Group) and IFS fractal compression technique were tested on corneal images and evaluated for use in teleophthalmology systems. In order to minimise the transmission time, images captured using a slit-lamp biomicroscope were compressed and transmitted through telephone lines to specialists for diagnosis of corneal diseases. These included traucomatous scarring, cataract, injuries or bacterial and viral infections. Subjective evaluation was performed by an ophthalmologist and the objective comparison was made using Root Mean Square (RMS) error between the original and the decompressed images. An average compression ratio of 73.1 was obtained using JPEG algorithm. A compression ratio of 23:1 was achieved using IFS fractal compression technique. The results indicate that JPEG compressed images were of diagnostic quality and could be used in teleophthalmology systems to achieve high compression reducing transmission time.