Technology Selection
Curtin supports three major display technologies – Projection, LCD displays and LED Walls. Devices should be first selected from the approved equipment list. Alternative devices will be considered for special purpose applications.
Due to the superior clarity and readability in bright spaces, DTS prefers the use of emissive and transmissive technologies like LCD and LED over the use of reflective technologies such as projection, with a preference to higher quantities of smaller, localised displays rather than the use of large video walls and projections
Flat Panel Displays
Flat panel displays (FPD) are to have a minimum resolution of 3840x2160
Displays are to be mounted such that the power, data and signal connectors are serviceable.
Where the screen is rebated into a wall, a pop-out bracket is to be utilised.
FPD’s are to be configured in line with either the model specific device configuration guidelines (where existing) or in accordance with the general device guidelines to ensure unused inputs are locked out, onscreen display elements are hidden and the display performance aligns to Curtin standards.
As display technology is constantly evolving and manufacturer model turn over is significantly high, DTS will attempt to maintain a list of supported displays, however this may not always be possible. Alternatives should be selected from the equivalent brands and ranges as the current approved models.
LED/Pixel Displays
LED Displays/walls require approval of DTS prior to deployment outside of digital signage applications
The primary issue is pixel pitch to closest viewer ratio. The closest viewer should be no closer than 1200 times the pixel pitch away from the screen (ie 0.9mm screen, closest viewer should be 1080mm from the screen).
Panel resolutions also need to conform with a 16:9 aspect ratio.
Colour reproduction is to be calibrated to sRGB and assurances of batched and matched LED spares needs to be established.
LED walls in teaching spaces are to be of Chip-on-Board (COB) type
Projection
Projectors should be placed such that the projected image requires no keystone or corner correction and minimal lens shift. The projected image should fill the screen surface edge to edge, corner to corner with no aberration due to lens curvature.
Projectors should be placed such that the projector lens is not sitting at the extreme edges of its zoom range.
The projector should also be placed at the top of the screen so as to give presenters a larger stage to work within.
Additionally, consideration should be given to the following:
- Projection path should be clear of obstructions
- Projector and screen should be accessible for maintenance
- Projector should have adequate room for ventilation
- Projectors shall not be keystoned or warped
- Projectors shall not be placed so as to be at the extremes of either zoom or lens shift.
- Projectors shall be mounted so that they are not effected by vibration from air handling or traffic on the floor above.
Projectors should be pole mounted in most circumstances. Where the ceiling height would put the projector in a location unreachable from an 8ft tall ladder, a motorised projector hoist with service height shall be used – this includes spaces with high ceilings and tiered lecture theatres.
All projectors must have a minimum native resolution of 1920x1080
Projection should be avoided where possible.
Projection Screens
Projection screens are to be from approved manufacturers. The surface shall be white unity gain (1.0) material to ensure optimum viewing angles.
Screens can be either fixed frame or motorised. Fixed Frame is preferred. Screens are to be 16:9 aspect. Motorised screens are to have IP control, and have a leader of no more than 600mm without approval from DTS AV. Where a screen needs to be more than 600mm from the ceiling, a double deploy arrangement can be used. Alternatively, the screen canister can be affixed to the wall, however the preference is for ceiling installation in a hide-away box.
Whiteboard surfaces are not acceptable surfaces owing to their extreme reflectivity. Where interactive projectors are being used, these should be paired with whiteboards designed for the associated ultrashort throw projector.
Walls may be utilised but only when painted with an approved projection paint. Standard flat white paint is not an acceptable surface finish.
Scaling & EDID management
Many Curtin University systems will contain a mixture of projection and flat panel displays. The integrator is required to manage EDIDs and ensure that all input points to the system are configured to limit available resolutions to those supported throughout all endpoints without the use of downscaling (ie if the venue has a projector with a native 1920x1200 panel supports 4k through the use of scaling as well as a pair of 4k FPD’s, the system resolution should be set to 1920x1080 as that is the highest common resolution with no scaling).
All destinations must be capable of 1920x1080@50Hz.
Where there are output devices which do not support 1920x1080, the video transport is to provide scaling of the signal at the destination.
Where AV over IP systems are being used for video transport, scaling may be enabled at either encode or decode – but not at both points. Scaling should only occur at one point in the system. In room displays should never downscale an input source.
Contrast Ratio
Appropriate contrast ratio is a critical criteria within Curtin University to ensure legibility of material, and it is a nexus point of a number of disciplines – including interiors, lighting and electrical and AV.
Utilising the PISCR classifications above, minimum ratios for contrast are described below. Noting however that these contrast ratios are not based on vendor contrast ratios, but rather established through the use of onsite testing once in situ.
Required contrast ratios under normal viewing conditions are:
| Room Type | PISCR Ratio |
|---|---|
| Passive Viewing | 7:1 |
| Basic Decision Making | 15:1 |
| Analytical Decision Making | 50:1 |
| Full Motion Video | 80:1 |
To calculate system contrast ratios in a projected room:
- Construct a 4x4 checkerboard test pattern and project it onto screen
- Allow system to warm up for a few minutes
- Set room lighting to standard mode
- Measure spot brightness using a spot photometer with a < 2° acceptance angle in the centre of each square
- Average the white measurements, then average the black measurements. Divide white by black
- Divide the left number by the right number of the PISCR ratio and compare the two values. If the measured value is higher, it has exceeded the contrast requirement
- Test for all light modes the screen may be utilised within
Contrast ratios may be improved by implementing automated blockout blinds, specialised lighting scenes, optimised surface treatments