|
In typical digital projection systems, increasing resolution
requires increasing the number of pixels in the spatial light
modulator (SLM). This significantly increases the area,
complexity, and cost of the SLM. SLMs are often the most
expensive component in a digital projection system.
"Wobulation" is a breakthrough method of increasing the
resolution of digital projection systems using a low-cost
relatively low resolution SLM. Multiple low-resolution
sub-frames of data are generated from each hi-resolution frame
of image data. An optical image shifting mechanism displaces the
projected image of each sub-frame by a non-integral number of
pixels. The sub-frames are projected in rapid succession so as
to appear as if they were projected simultaneously and
superimposed.
                   
Technology contributions:
- Developed a general signal processing model for Wobulation.
The model supports arbitrary pixel shapes, sampling grids and
relative "wobble" offsets.
- Formulated a general theory of Wobulation as an inverse
super-resolution reconstruction. The theory lies at the
intersection of halftoning (bit-depth reduction), image
deconvolution, multidimensional sampling, and super-resolution.
- Formulated key algorithms for optimal wobulated image
quality. The following are examples of key signal processing
problems that were solved
-
Optimal subframe generation:
An optimal algorithm was developed to process
a high-resolution image into the component low-res subframes for
the best overall image quality. Naive approaches that seek to
directly sample the high-resolution image into subframes discard
important image features that "fall through the cracks in the
sampling" (see center image). Naive pixel interpolation approaches produced blurry
output images.
-
Optimal bit-depth recovery: Since the Wobulation relies on temporal
multiplexing of subframes, the available bit-depth per subframe
is significantly reduced leading to visible contouring artifacts
if precautions are not taken. By processing the subframes using novel algorithms the bit-depth may be recovered
when the subframes overlap on the screen. This allows wobulation
to reproduce graylevels without any visible artifacts.
News Links:
Patents (HP Internal)
|
 |
|
Printable version
