Gesture recognition approaches broadly fall into three categories: rule-based geometric methods, classical
machine learning classifiers, and deep learning models. Rule-based methods, which compute explicit geometric
features such as inter-landmark distances, finger extension ratios, and angular relationships, remain widely
used due to their interpretability, low computational overhead, and absence of training data requirements.
[15]
The pinch detection mechanism employed in this system computing the Euclidean distance between thumb and
index finger landmarks is representative of this approach. Machine learning-based classifiers, including Support
Vector Machines (SVMs) and Random Forests trained on hand landmark feature vectors, have been reported to
perform well on static gesture recognition tasks.
[16]
Dynamic gesture recognition, which requires temporal
modelling of landmark sequences, has been addressed through Hidden Markov Models (HMMs) and, more
recently, through recurrent neural networks (RNNs) and Long Short-Term Memory (LSTM) networks.
[17]
While
these approaches offer greater expressiveness, they introduce training data collection burdens and inference
latency that complicate deployment on edge hardware. A relevant design idea is evidence accumulation for
gesture intent classification. Rather than triggering an action on a single-frame threshold crossing, confidence
accumulation integrates evidence across multiple frames. Real-time gesture recognition systems such as that
of Köpüklü et al. likewise make multi-frame decisions, using sliding-window detector and classifier queues with
post-processing and a single-time activation mechanism so that each performed gesture is activated once; that
work is based on 3D CNN models and does not evaluate a pinch-confidence accumulator or demonstrate a false-
positive reduction from the mechanism used here.
[18]
The intent engine in this paper applies multi-frame
accumulation as a design rationale, namely that a click should be registered only after sustained evidence, and
adds a velocity gate that suppresses click accumulation during rapid hand movement. The effect of this design
on false positives was not measured in this work.
2.3 Signal smoothing and cursor stabilization
A persistent challenge in webcam-based cursor control is the translation of noisy, jittery landmark coordinates
into stable, usable pointer positions. Casiez et al. introduced the 1€ Filter (One Euro Filter), an adaptive low-
pass filter that dynamically adjusts its cutoff frequency based on the signal's instantaneous velocity.
[19]
At low
velocities, strong smoothing suppresses jitter; at high velocities, the filter relaxes to preserve responsiveness.
This filter is widely used in interactive systems, and it is applied in this work to address the tremor and
quantization noise in Media Pipe landmark output; its effect here was assessed only in a single stationary-hold
pilot (Section 6.5). Physics-based cursor models, which simulate Newtonian dynamics including mass,
momentum, and friction, represent a complementary approach to stability. By giving the cursor virtual inertia,
abrupt directional changes caused by hand micro-movements are naturally attenuated while intentional large
movements remain responsive. Prior work in pointing facilitation, including the Bubble cursor technique, has
examined how cursor behaviour can affect target acquisition, although it does not use inertial dynamics.
[20]
The
physics-based cursor implemented in this system is therefore motivated as a design rationale for attenuating
jitter rather than by direct evidence from.
[21]
2.4 Touchless interfaces for public environments
The design of touchless interfaces for public kiosks and shared terminals has received growing attention,
particularly following the COVID-19 pandemic. The multi-mode interaction design adopted in this work uses
distinct cursor, scroll, and pause states. This design is intended to reduce the cognitive load associated with
continuous gesture maintenance. Leap Motion Controller-based systems have been demonstrated for
contactless ATM and touchless elevator interaction, but they depend on dedicated hardware.
[21,22]
Vision-only
approaches using standard RGB cameras, as proposed in this work, may be more economical to deploy at scale
and require no modification to existing terminal hardware beyond software installation and a camera;
economic viability was not assessed. Accessibility considerations further motivate touchless gesture interfaces.
Users with motor impairments that prevent reliable touchscreen contact, individuals with prosthetics, and
elderly users with reduced fine motor control may benefit from gesture-based alternatives; touch-free gesture
interaction for users with dexterity impairments is examined in.
[23]
The user-defined gesture learning
subsystem introduced in this work is intended to support accessibility by allowing individuals to define
gestures suited to their physical capabilities; this was not evaluated with users.
3. System design and architecture
3.1 Design philosophy and goals
The architecture of the AI-Powered Gesture Control system for public touchscreens was guided by four primary
design principles. First, modularity each functional concern is encapsulated in an independent, replaceable
module, allowing individual components to be upgraded or substituted without affecting the rest of the pipeline.
Second, low latency the system is designed to minimize end-to-end delay from hand movement to cursor
response, targeting real-time performance on commodity hardware without GPU acceleration. Third,
robustness the system must tolerate natural hand tremor, involuntary micro-movements, transient pose