Infrared Weight Estimation

Senior Capstone Project

In emergency situations, it is critical to obtain an accurate estimate of a patient's weight prior to administering any kind of weight-based medication. My final project involved estimating a patient's body weight using a set of infrared cameras and code to send information to hospital charting software. This device offers a quick and safe alternative to mechanical scales and subjective visual estimation. The infrared system is able to accurately estimate the weight in the range of children through obese patients, with database controls for body type, clothing weight, and anatomical abnormalities. Below is a comparison of the methods for weight estimation that are currently in use, as well as the associated resources, time, and error amounts for each.

This new device is necessary for getting an accurate weight estimate of stroke or spinal trauma patients upon first response. The University of Cincinnati's Medical Device Innovation Entrepreneurship Program provided my team with a budget and the necessary infrared camera resources for completing the project. Another biomedical engineer and myself learned how to develop mobile applications, process infrared data sets, and create dynamic database tabulation systems for accumulating and processing weight data. The final prototype boasts an accuracy within 5% of actual body weight, a low-profile for use in ambulances, helicopters, & emergency rooms, and reliability across a multitude of body types. Pictured below is a simple diagram showing how both the Anterior and Lateral pictures come together to form a simple volume model from which weight can be categorized and obtained.

Shown below are some of the input images that the code uses to output a weight estimate. These images were taken using the FlirOne infrared iPhone camera.

The algorithm we created uses a series of iterative volume calculations to zero in on an appropriate weight estimate.

This program required me to take all of the skills learned in my engineering classes and on Co-op to complete a final medical device design project. During the process, we discovered that the amount of design necessary to compensate for all possible scenarios would be extremely expensive. As a result, my team proposed an alternate solution to add force guages to the legs of modern emergency stretchers. This method outputs an accurate weight, with simple calculations and ease of connectivity to charting systems.