The interpretation of radiograms is ordinarily done by the eye of an attending physician or dentist and, for this reason, there is much possibility for subjective difference to creep in this kind of diagnostic information handling. The subjective difference is principally accounted for by the degree of familiarity which the physician or dentist has with his specialized subject and that of his experience in the art of radiographic interpretation. At any rate, it is believed that the physician or dentist will increase his skill in proportion to his exposure to the clinical experience. Although this belief is by no means wrong, there is lacking a definite metrical element in this kind of subjective analysis. The present report is concerned with our efforts of indroducing as much objective interpretation as possible into the radiographic analysis in dental field by the conjoint use of an electronic computer and micro-photometer.