Options and Specifications
The Video Gauge is available as either a laptop or desktop based system. All drivers and software are pre-installed and the system is ready to use.
The system is delivered in a rugged flight-case which houses:
- One or more digital video cameras
- Lenses suitable for application (see options below)
- Voltage input/output module (optional)
- Target marking kit
- Laptop (if laptop version has been chosen)
The various system options are detailed below.
Lenses
Lenses are characterised by their Field of View (FOV). This is the size of the area that is visible in the image. A lens should be chosen so that its field of view is suitable for the application.
Another important characteristic of a lens is its Working Distance (WD). This is the distance between the lens and the object being measured. Some lenses have a fixed working distance but most operate over a range.
The following general-purpose lenses are suitable for most applications. They operate over a large range of working distance. Their field of view is proportional to the working distance: doubling the working distance will double the field of view.
| Focal length (mm) | Min WD (mm) | Max WD (mm) | At min WD | At 1m WD | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FOV (mm) | Displacement resolution (μm) | Strain resolution (με) | Gauge length (mm) | FOV (mm) | Displacement resolution (μm) | Strain resolution (με) | Gauge length (mm) | |||
| 16 | 142.2 | ∞ | 52.9 | 0.53 | 20 | 13-40 | 372 | 3.7 | 20 | 93-279 |
| 25 | 148.3 | ∞ | 35.3 | 0.35 | 20 | 9-26 | 238 | 2.4 | 20 | 60-179 |
| 50 | 191.8 | ∞ | 22.8 | 0.23 | 20 | 6-17 | 119 | 1.2 | 20 | 30-89 |
| 75 | 497.0 | ∞ | 39.4 | 0.39 | 20 | 10-30 | 79 | 0.8 | 20 | 20-59 |
The minimum WD of these lenses can be reduced with the use of extension rings. This results in a reduced FOV and enables smaller gauge lengths.
The following lenses are specifically for material testing applications. They offer superior resolution over the general purpose lenses and are ideal if the test may involve out-of-plane movement. These lenses have a fixed working distance.
| WD (mm) | FOV (mm) | Min gauge len (mm) | Max gauge len (mm) | Max out-of-plane movement (mm) | Strain resolution (με) |
|---|---|---|---|---|---|
| 70 | 24 | 6 | 19 | +/- 4 | 5 |
| 543 | 25 | 6 | 19 | +/- 5 | 5 |
The working distance of these lenses can also be reduced with the use of extension rings.
The 543mm working distance lens is ideal for applications where it is not possible to get the camera close to the test specimen such as high-temperature testing.
Camera
This is a high-resolution monochrome digital camera. Multiple cameras can be connected allowing measurements in multiple areas simultaneously.
- 1/2” monochrome CCD
- 1280 x 960 pixels
- 4.65μm square pixels
- 15, 7.5, 3.75 or 1.875 frames/s
- Shutter speed 1/10,000s to 17.5s
- Trigger input: TTL, >10μs pulse width
When trigger function is disabled a signal indicating exposure time is output. This may be connected to the trigger input of other cameras to synchronise them. - Connects to PC via 1394a firewire port
Each camera is supplied with a firewire cable and standard tripod mount adapter.
Voltage input/output module
This module provides both analogue and digital inputs and outputs.
- Analogue inputs
- Channels: 16 single ended / 8 differential
- Resolution: 16 bit
- Voltage ranges: +/- 0.2V to +/- 10V (4 ranges)
- Analogue outputs
- Channels: 2
- Resolution: 16 bit
- Voltage range: +/- 10V
- Digital inputs
- Channels: 4
- Logic levels: TTL
- Digital outputs
- Channels: 4
- Logic levels: TTL
- Input/output connector: screw terminals
- Connects to PC via the USB port
Imetrum can also supply BNC sockets with leads suitable for connecting to the screw terminals.
Lighting
The light system is fitted with three low energy fluorescent lamps. These give a cool diffuse light that is as bright as a 250W tungsten lamp.
It is safe to use, even when measuring objects that are easily affected by heat. The light is supplied complete with fully adjustable stand.
- Height: 85cm to 195cm
- Power: 230VAC
(can be supplied for 120VAC if required)
Tripod
This is a sturdy and flexible tripod for mounting the camera. Supplied with a 3-way pan-tilt-swivel head that incorporates a spirit level to ensure the camera is set up level.
- Height: 77cm to 178cm