Abhishek Sebastian.

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UWB Gestures · 2023–2024 · Radar sensing · Samsung PRISM

Seeing a gesture without a camera.

Turning ultra-wideband radar measurements into recognisable hand gestures, from noisy sensor data to a working inference interface.

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Inside the system / interactive concept

A signal becomes a gesture.

01 / 03

Capture static gestures at 10, 25, and 50 cm, including periods where no gesture is being made.

Conceptual pipeline. Selecting a stage does not run radar inference.

Published UWB radar heatmaps before and after outlier mitigation
Figure 2 · Radar representations before (a) and after (b) outlier mitigation. Sebastian & Pragna, UWB project report ↗

Findings from the project report

Gesture vocabulary
5 + 1

Five static gestures, plus a no-gesture class for inactivity.

Capture distances
10–50 cm

Measurements at 10, 25, and 50 centimetres.

Reported best accuracy
96.78%

CNN v3 superclass accuracy in Table 1 of the project report.

Source: arXiv:2310.15036v3. The report uses a random 70:15:15 train/validation/test split; this is not evidence of performance on entirely new users or a deployed consumer device.

Give the radar a vocabulary

The collection covered OK, VICTORY, STOP, PALM, and LIKE at three distances. A no-gesture class gave the system a way to recognise inactivity. The report records 9,360 seconds of data, with 5–12 participants across the gesture groups.

The work before the network

Rolling-median and Z-score processing reduced outliers. Measurements became false-colour images, then were resized while preserving aspect ratio. The before-and-after figure shows this step: the model receives a representation of radar returns, not a photograph of a hand.

Accuracy was only one part

We compared CNN and MobileNet variants, then built a GUI to inspect predictions, processing time, and memory use. The best reported superclass accuracy was 96.78%. Evaluating resource use alongside predictions made the result more useful than an accuracy number alone.

UWB project GUI displaying a gesture prediction, measured processing time, memory usage, and processed radar image
Figure 4 · The evaluation interface used to inspect predictions and resource use. Values are from the published screenshot. UWB project report ↗