SprayQuantAI® SQA1

SprayQuantAI® SQA1 is the compact single-channel configuration of the SprayQuantAI® measurement platform. It combines the LSS1 optical probe with the ZEON control unit for time-resolved measurement and evaluation of individual droplets or particles.

SQA1 is designed for applications where droplet or particle properties need to be measured with compact optical hardware. The system records one time-resolved light-scattering signal for each detected particle event and evaluates this signal using the configured SprayQuantAI® calculation method.

A central application of SQA1 is AI-based individual-particle evaluation, where a trained machine-learning model determines particle properties directly from a single measured light-scattering waveform.

SQA1 consists of three main elements: the optical measurement probe, the control and acquisition unit, and the SprayQuantAI® measurement software.

Component	SQA1 Configuration	Function
Optical probe	LSS1	Generates the measurement region and detects the time-resolved scattered light
Detector channels	1	Records one optical waveform for each detected particle event
Control unit	ZEON	Signal acquisition, processing, calculation and process communication
Evaluation	SprayQuantAI®	Individual-event evaluation and spray monitoring

The LSS1 optical probe creates a specifically shaped illumination field. When a droplet or particle passes through the measurement region, it scatters light toward the optical detector.

The motion of the particle through the spatial light distribution generates a characteristic time-dependent light-scattering waveform. This signal contains information about the interaction between the particle and the optical measurement field.

ZEON acquires the signal with high temporal resolution and transfers the measured waveform to the configured SprayQuantAI® evaluation method.

SQA1 uses one active optical detector channel. This makes it the most compact standard configuration within the SprayQuantAI® platform.

The detector records a complete time-resolved waveform rather than only a single intensity value. Information can therefore be distributed across the signal shape, amplitude, characteristic positions, widths, and temporal structure.

For AI-based operation, a trained machine-learning model can use this waveform to determine particle properties such as size and velocity.

A key concept behind SQA1 is the use of artificial intelligence to extract quantitative particle information from a single measured light-scattering waveform.

During development of the AI model, reference measurements can be generated using a more extensive multi-detector measurement configuration. Known reference values, such as particle size and velocity, are assigned to the corresponding single-channel waveform.

After training and validation, the model can analyze newly measured LSS1 signals and predict the required particle properties using the compact SQA1 hardware configuration.

This concept makes it possible to reduce the optical and electronic complexity required for specific measurement tasks while retaining quantitative particle information.

Depending on the configured measurement method and AI model, SQA1 can provide information such as:

• droplet or particle size
• droplet or particle velocity
• particle or droplet number
• particle event rate
• size distributions
• velocity distributions
• temporal spray trends
• spray stability indicators
• process monitoring values

The exact available parameters depend on the optical configuration, measured material, operating range, and validated evaluation model.

The LSS1 is the single-channel optical probe used by SQA1. It generates the illumination field, defines the measurement region, and detects the scattered light produced by individual droplets or particles.

The probe is connected to ZEON by optical fiber. This allows the optical measurement location to be separated from the control and acquisition electronics.

Parameter	LSS1
Measurement principle	Time-resolved light scattering
Active detector channels	1
Wavelength	405 nm
Dimensions	182 × 74.9 × 32 mm
Mechanical mounting	M3
Control unit	ZEON

Technical details for LSS1

The ZEON control unit provides signal acquisition, calculation, system control, communication, and interfaces for external process integration.

ZEON receives the optical signal from LSS1 and converts it into digital measurement data. Depending on the configured operating mode, the system evaluates individual events, calculates spray parameters, stores measurement values, and transfers selected results to external systems.

Parameter	ZEON
Optical signal inputs	1
Host communication	Ethernet
Digital inputs	4 × 24 V
Digital outputs	4 × 24 V
Analog inputs	4 × 4–20 mA
Analog outputs	4 × 4–20 mA
Trigger	Trigger input and output
Dimensions	251 × 211 × 109 mm

Technical details for ZEON

SQA1 is designed not only for laboratory measurements but also for continuous monitoring of spray processes. Individual droplet measurements can be accumulated over defined evaluation intervals to generate continuously updated process values.

Parameters such as average droplet size, velocity, particle number, or spray stability can therefore be monitored over time. Changes in the measured spray can be compared with defined reference conditions.

The ZEON interfaces allow selected measurement values and system status information to be transferred to external monitoring and automation systems.

SQA1 can be integrated into existing laboratory or industrial infrastructure through standard communication and process interfaces.

• Ethernet communication with the host computer
• digital inputs and outputs
• 4–20 mA analog inputs and outputs
• external trigger input and output
• transfer of calculated process values
• integration into monitoring and automation systems

The 4–20 mA interfaces are particularly useful for connecting SprayQuantAI® measurement values to established industrial process-control environments.

• paint and coating spray monitoring
• spray gun characterization
• nozzle development
• atomizer development
• droplet size and velocity measurements
• spray stability monitoring
• quality assurance
• laboratory spray research
• integration into automated production systems

SQA1 can be adapted to the measurement task. The appropriate configuration depends on the spray system, material, expected droplet properties, atomizer geometry, available installation space, and required process information.

Possible adaptations include optical working distance, probe geometry, mechanical mounting, illumination configuration, software settings, AI model, and process interfaces.

For industrial applications, the mechanical integration of the LSS1 probe with the spray gun, nozzle, atomizer, or production equipment can form an important part of the measurement solution.

SQA1 and SQA2 use the same SprayQuantAI® measurement concept but differ in the number of active optical detector channels.

Parameter	SQA1	SQA2
Optical probe	LSS1	LSS2
Control unit	ZEON	IMEA
Detector channels	1	2
Measurement concept	Individual particle events	Individual particle events
Primary advantage	Compact optical configuration	Additional synchronized optical information

SQA1 is particularly suitable when a compact single-channel configuration provides sufficient information for the required measurement model. SQA2 provides a second synchronized detector channel when additional optical information is required.

SQA1 and ParticleTensorAI® PTA1 use the same LSS1 and ZEON hardware platform. The difference lies in the acquisition and evaluation concept.

SQA1 focuses on individual droplet or particle events. Each event is detected and evaluated separately before the results are combined into statistical spray parameters.

PTA1 instead retains longer buffered signal sequences and evaluates them using the ParticleTensorAI® tensor-based AI approach.

The measurement technology behind SQA1 builds on the Time-Shift-Time-of-Flight approach for optical characterization of droplets and particles and subsequent research into machine-learning-based evaluation of individual light-scattering signals.

Experimental research demonstrated that particle size and velocity can be predicted from a single light-scattering signal using a machine-learning model trained with reference information from a more extensive TSTOF measurement configuration.

[1] Schaefer, W.; Li, L. Particle characterization by analyzing light scattering signals with a machine learning approach. Applied Optics 2024, 63(29), 7701–7707. https://doi.org/10.1364/AO.531346

[2] Schaefer, W.; Li, L.; Stegmann, P.; Terada, M. Technical Report on the TSTOF Measurement Method: Technical Basics, Historical Development, and Comparison with Other Laser-Based Measurement Methods. Photonics 2026, 13(1), 56. https://doi.org/10.3390/photonics13010056

[3] Schäfer, W. Verfahren und Vorrichtung zur Charakterisierung der Teilcheneigenschaften durch Auswertung eines Streulichtsignals mittels eines maschinellen Lernmodells und Reduzierung des primären Apparates. German Patent Application DE102023134228A1. Patent applicant: ai-quanton GmbH.

• SprayQuantAI® Overview
• SprayQuantAI® SQA2
• LSS1 Optical Probe
• ZEON Control Unit
• ParticleTensorAI® PTA1

For an application-specific SQA1 configuration, contact ai-quanton with information about the spray, atomizer or nozzle, material, expected droplet properties, operating conditions, and required measurement results.