Abstract
In order to operate a camera-based patient monitoring system that detects when a patient gets up from or leaves the bed at hospitals and care facilities, we developed a technology to recognize the position of a bed at a high speed and with high accuracy. The conventional technology is not well-suited for use in a hospital setting because processing requires an excessive amount of time, the camera needs to be set at a particular position, and there must not be any objects on or around the bed. In this paper, we propose a method that distinguishes between a bed and other objects by hierarchically deciding if each line segment in the image comprises the outline of a bed or not. For each level in the hierarchy, we filtered the candidates passed to the next level based on shape features and other shape-independent features. By using the proposed method, we were able to accurately recognize a bed area at a high speed and with high accuracy even when the camera was placed at various positions and other objects were present on or around the bed.
