The DepthQ^® 360 is a greyscale 1280x720 DLP projector that outputs luminance frames at 360Hz. Developed in collaboration with scientists at HHMI Janelia Farm, this novel display solution was engineered specifically for rendering high temporal and spatial resolution images for vision research. Use it with ViSaGe, or Bits# and Psychtoolbox for wide field of view visual neurophysiology studies or combine with active shutter glasses to create immersive, stereoscopic environments.

Technical Description

The DepthQ^® 360 is a single chip DLP projector with no colour wheel. It has a standard analogue VGA input and will synchronise to any computer graphics card that can produce 1280x720 24 bits per pixel RGB encoded video at 120Hz (i.e. screen resolution 1280x720, frame rate 120Hz, 16.7 million colours). It outputs 1280x720 8 bits per pixel greyscale displays at up to 360Hz. By sacrificing all colour capability, additional luminance temporal resolution is obtained.

• 360Hz control is achieved by encoding the usual RGB planes in each 24-bit video frame as three unique 8-bit greyscale sub-frames (i.e. the Red channel is now sub-frame A, the Blue channel is now sub-frame B, and the Green channel is now sub-frame C). Note that sub-frames are transferred from the graphics card memory to the projector in the usual RGB order but are output by the projector in the order BRG.
• Each 8.33ms input frame of 120Hz RGB video is output as 2.78ms sub-frame 1, 2.78ms sub-frame 2, 2.78ms sub-frame 3. 
• Each sub-frame is separated by 100 microseconds of darkness.
• All 1280x720 pixels on the DMD update simultaneously with no scanning.
• There is a fixed 20ms latency between the input and output.
• There are no added luminance frames or other contrast enhancing effects.
• The usual nonlinear processing of video frames to add a CRT-like gamma function has been deactivated in the projector firmware as much as possible.
• The projector has a highly linear transfer function with no observable hysteresis.
• Further firmware modifications allow the supplied arc lamp light source to be easily removed from the projector and an alternative light source substituted in its place.
• Optical spacers for the built-in (but removable) lens have been developed to allow the projectors to produce focused images from 1cm to a meter+ in size.

Screen Sizes

The default integrated zoom lens supports the following screen sizes: