Particle Shadow Velocimetry Packaged System 

Superior Safety - Educational Price

Cost and safety issues associated with laser-based particle image velocimetry systems effectively eliminate their use in undergraduate student training.  ISSI has developed a cost-effective alternative, Particle Shadow Velocimetry (PSV), illustrated below:

PSV Setup


PSV uses light extinction (particle shadows) rather than light scattering in a laser sheet, resulting in high-quality particle imaging at much lower illumination levels.  These safe illumination levels can be generated by a pulsed-LED system at a fraction of the cost of a pulsed laser.  Multi-color LED illumination permits the use of a low-speed camera, further reducing system cost.  Different color LEDs are sequentially pulsed, at high speed, and the sequential particle images are captured in a single frame on the camera’s three color planes.  Narrow depth-of-field optics are employed to image a two-dimensional plane within the flow volume, similar to what is achieved with a laser sheet.  Measurement close to surfaces is possible because the system is not degraded by surface reflections which severely limit laser-based systems.  The PSV approach is fully compatible with the seeding approaches and specifications used with conventional PIV systems.

PSV Config

System Components

3-Color RGB LED Light SourceRGB


The LM2X-DMHP-RGB is an LED light source that provides 3 color (Red, Green, and Blue) outputs from its LED head. This LED is used for Particle Shadow Velocimetry (PSV) to illuminate small seed particles in a flow field to measure velocity and particle density. The LM2X-DMHP-RGB has 3 BNC inputs to control the timing and pulse width of each of the output colors from an external pulse generator. The pulsed LED operation is controlled by applying a TTL voltage to the external BNC(s) on the module. The rise time is less than 200-ns and the fall time is less than 100-ns and the duty cycle is 5%. The light distribution from the unit is approximately Gaussian for distance greater than 18 inches from the source.


3-Color RGB LED Datasheet.pdf


Pulse/Delay GeneratorPSG-3

(Product ID: PSG-3)  


The PSG-3 is a four channel pulse/delay generator used for controlling the timing of experiment parameters and can be used as an experiment master clock or externally triggered (or gated) by an external event. Pulse width, delay, repetition rate, and other timing parameters are controlled by a simple internet browser interface and communication is via ethernet connection. No software installation is needed and the PSG-3 is Mac or PC compatible. API commands also available to allow the PSG-3 to be incorporated into a larger data acquisition system via either ethernet or USB 2.0.


PSG-3 Datasheet.pdf

PSG-3 User Manual.pdf

3D CAD Drawing.pdf

User Interface: PSG-3 User Interface v1.5.3

Drivers: PSG-3 Drivers

Latest Firmware: PSG-3 Firmware


Product ID: PSP-CCD-C

The PSP-CCD is a 2-megapixel CCD camera.   The camera is small and lightweight at 210g allowing for an array of cameras to be mounted in a tight place for larger scale models and applications.  Communication with the PSP-CCD is via Gigabit Ethernet.  The camera comes in two styles, one with a color array and one with a monochrome array.  The color camera is used in Binary PSP and particle shadow velocimetry applications whereas the monochrome version is used in monochrome PSP or S3F applications. 




PSP-CCD Datasheet.pdf

PSP-CCD User Manual.pdf

User Interface: ProAcquire 2.5.3_GigE x64.exe

User Interface: ProAcquire 2.5.3 GigE x86.exe


Optical Kit

Product ID: OP-K-PSV

Between the camera and the lens, variable width AF bellows are used to move the lens away from the CCD sensor of the camera.  The bellows will provide a magnified field of view wiith narrow depth of field.  This also reduces the amount of light coming into the camera, further narrowing the depth of field.  The ideal depth of field for PSV is 0.5 to 1.0 mm.  This is done so that a 2D sheet of particles is imaged, with all out of plane particles out of focus.  The velocity vectors obtained are only in 2-dimensions.  A similar technique is used in Particle Image Velocimetry (PIV), except a laser is used in place of an LED to illuminate particles.  

PSV Optics KitVariable AF Bellows with Canon® EF Lens Controller





OP-K-PSV Datasheet.pdf


Example Data

PSV System User Manual.pdf

PSV Setup

PSV Experimental Setup


Cylinder in Cross-Flow

PSV Data

Velocity Vectors

For ordering information, please contact our sales department: or call us at (937) 630-3012