Calibration‐Free Height Estimation for Person

Abstract

Demand for use of indoor and outdoor surveillance cameras to prevent crime, analyze customer behavior in commercial facilities and other purposes has been increasing. For these types of applications, it is important to be able to estimate information that cannot be observed directly from the images, using the image data. One such type of information is the height of people appearing in the video. People's heights can be used, for example, to help identify a suspect in a crime investigation or as an attribute to understand customers better for marketing. However, many conventional technologies for estimating height from images have required special calibration, or the acquisition of other information in addition to the video. This paper proposes a method for estimating a person's height using only an image, without the need for any special calibration. The key points of the proposed method involve the following two processes. In the first process, a reference object of known size and the person are recognized and the person's height is estimated based on the relative sizes of the person and reference object in the image. The second process involves selecting frames from the video that are appropriate for use in the estimation process. In practical experiments using real video, the method was able to estimate people's heights with an average estimation error of 1.9%. © 2024 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.