In this report, we describe in detail the design and usability testing of a touchscreen interface for multimodal biometric capture, an application called WSABI, Web Services for the Acquisition of Biometric Information. The application code is publicly available online at https://github.com/NIST-BWS/wsabi2
. The interface is a tablet-based reference application for the Web Services for Biometric Devices (WS-BD) protocol. Just as WS-BD specifies a method of communication between client and sensors (i.e., machine-to-machine communication), WSABI provides a consistent and modality-independent method of interaction between human operators and sensors (i.e., human-to-machine communication). The interfaces common capture cards look and function the same across all modalities and all sensors; regardless of the biometric modality or sensor, users perform the same actions to capture, annotate, clear, and retake biometric data. Similarly, users perform the same method of sensor setup regardless of the biometric modality or sensor. Most importantly, this design and functionality has been tested and found successful with real users, participants ranging in age, education, and tablet experience, who were unfamiliar with biometrics and given no training on the application. Given the success of the user-centered WSABI design, NIST recommends that requirements for new systems include the guidelines in the Design Recommendations section of this document; including requirements will yield a more effective and efficient user interface for biometric operators, saving both time and money on operator training.