An infrared diagnosis device provides two-dimensional images and patient-oriented results that can be easily understood by the inspection target by using infrared cameras. However, this device has disadvantages such as large size, high price, and inconvenient maintenance. In this regard. this study has proposed a small diagnosis device for body heat using a single infrared sensor and implementing an infrared detection system using a single infrared sensor and an algorithm that represents thermography using the obtained data on the temperature of the point source. The developed system had a temperature resolution of 0.1 degrees C and reproducibility of +/-0.1 degrees C. The accuracy was 90.39% at the error bound of +/-0 degrees C and 99.98% at that of +/-0.1 degrees C. To evaluate the proposed algorithm and system, the infrared images of the camera method were compared. To verify the device's clinical applicability, thermal images with clinical meaning were obtained from a patient who had lesions. (C) 2009 Elsevier B.V. All rights reserved.