The secrets of BOLDscreen 3D...

As a scientist, you need to know the advantages and limitations of the technology you use, and understand which features really affect the quality of your stimulus. There are no secrets to Cambridge Research Systems' products - just good engineering, which we are happy to explain. If you don't find the answers you're looking for here, please drop us an email.

My experiment requires accurate stimulus timing.
Can I rely on BOLDscreen 3D to present my images synchronous with the display driver in the source PC?

Yes - all our BOLDscreen monitors offer uniquely accurate timing.

Most MR Safe monitors were originally designed for TV or PC use, and will lag behind the input signal by many frames, in an uncontrolled way. But timing can be crucial in scientific applications. BOLDscreens are designed to deliver your video signal directly to the screen. There is a very small fixed delay equal to just one horizontal line (~100 microseconds).

Do I need a bigger display?

The 23” display provides a reasonable field of view for a 60cm bore. BOLDscreen 3D is designed to be placed in close proximity to the viewer right at the exit of the bore of the scanner. This keeps the viewing distance is as short as possible - about 1m. Since viewing distance dramatically affects the field of view, BOLDscreen 3D can often achieve a larger field of view than bigger monitors with longer viewing distance. If you want a bigger monitor or have a 70cm bore, consider the larger BOLDscreen 32 design.

How do I create dichoptic displays? Do I need a special graphics card?

The BOLDscreen 3D monitor has a single-link DVI input and can be used with any computer and graphics card that has a DVI, HDMI or DisplayPort output. For dichoptic displays, stimuli must be created so that the left/right views are encoded on alternate lines (horizontal spatial interleaving). For example: image line 0 = left eye image line 0, image line 1 = right eye image line 0, image line 2 = left eye image line 1, image line 3 = right eye image line 1 etc. - the LCD panel has 1080 lines in total, so the left eye image contributes 540 lines and the right eye image contributes 540 lines on each 1080 line video frame.

What's the trade-off when BOLDscreen 3D is displaying dichoptic stimuli? Are 2D images compromised?

The LCD panel native resolution is 1920x1080. When used as a standard 2D display device the full spatial resolution is available as all pixels and lines are seen by both eyes. However when used as a dichoptic display device and the observer wears circular polarising glasses, the left eye will see 1920x540 and the right eye will also see 1920x540 within the same video frame. The important point is that all video frames encode left and right eye images, just at half the vertical spatial resolution. The pixels are not compressed or stretched; it's just the aspect ratio that changes. The FPR layer has no effect on contrast, but the circular polarising filters attenuate the light transmission.

How does BOLDscreen's fixed resolution ensure that what you put in is what you get out?

BOLDscreen 3D operates at a fixed resolution of 1920 x 1080 @ 60Hz.

Scaling and resampling by the stimulus monitor is highly undesireable, as it changes your stimulus and timing in uncontrolled ways. BOLDscreen is purposefully designed with no image processing circuitry, so that unlike other monitors, you can be sure that what you put in is what you get out. If you need to scale you image, we recommend using your computer's graphics card.

How does BOLDscreen's contrast ratio compare with other displays?

Some manufacturers quote high contrast figures which compare white versus black with the screen switched off. We don't think that's a useful measurement, as the screen is not switched off when you're presenting stimuli! We measure the contrast between the emitted light though the panel with the pixels set to white versus set to black with the same backlight intensity – what you see in actual use. Measured in this way, BOLDscreen D3 has a typical contrast ratio of 1000:1, similar to most high quality LCD displays.

Why is built-in calibration an essential feature?

The output of an LCD display varies greatly over time – typically luminance will change by up to 20% in the first hour and a half after turning the screen on. BOLDscreen 3D offers real time luminance calibration ensuring a stable, calibrated display immediately from switch-on, and maintaining the same level of output even when BOLDscreen 3D has been running for hours.

Can I change any settings on BOLDscreen itself?

Yes. We designed BOLDscreen 3D without physical buttons, as they can cause electromagnetic interference, and are susceptible to accidental changes! Instead, all settings are easily configured on a removable SD card.

If my subjects view BOLDscreen 3D via a headcoil mounted mirror, how will “mirror-mode” make things easier?

The mirror mode feature allows you to automatically left/right flip your image when your subject is viewing the display via a single mirror, without the requirement to manually adjust your stimuli.

What fibre optic cables are included when purchasing BOLDscreen 3D?

We provide a 20m single link DVI fibre optic cable with each BOLDscreen 3D display. This is passed through the waveguide into the control room and connected to your host computer DVI output. The cable has integrated transmitter and receiver elements, so there's no chance of them getting lost.

Can BOLDscreen 3D really be placed right next to my scanner without causing interference?

We are the only manufacturer and vendor that provides a MR Safe LCD monitor that you can site anywhere inside the MRI room, even directly at the exit of the rear of the magnet bore so that you can maximise the visual field of view.

BOLDscreen 3D has no observed effect on functional and structural MRI scans at 3T, even when located at directly at the exit of scanner bore, and no effect on displayed image whilst scanning.

How can an electronic device like a monitor be MR Safe?

BOLDscreen 3D is constructed mostly from aluminium, 316 stainless steel, glass and plastic. These materials are non-magnetic. There is a very small amount of ferro-magnetic content due mainly to nickel plating on some miniature electronic components, and some tiny ferrite components. This content is of the order of a few grammes in a total monitor mass of about 10kg. The BOLDscreen electronics have been designed to work in the high magnetic field (it is not just a normal LCD monitor in a screened box). There is therefore no electrical hazard from operating BOLDscreen 3D in the magnetic field of any field strength. The display is MR Safe, and the power supply and cables are MR Conditional, as defined by ASTM F2503-08.

I'm still not sure - can I try out BOLDscreen 3D for 60 days before I decide?

We want all of our customers to be very happy with the equipment we supply. Please contact us to discuss your requirements, and we will help you to assess whether BOLDscreen 3D or another one of our BOLDscreen monitors is the best solution for your research.

If you're still not sure, ask us for a 60 day trial: you place an order for BOLDscreen 3D in the normal way, then you have 60 days to try it out with your scanner, with the option to cancel if you decide that it's unsuitable in any way.