J Christmas

Publications (2)3.33 Total impact

• Article: Liquid crystal over silicon device characteristics for holographic projection of high-definition television images.

  A Georgiou, J Christmas, J Moore, A Jeziorska-Chapman, A Davey, N Collings, W A Crossland
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  ABSTRACT: We discuss some fundamental characteristics of a phase-modulating device suitable to holographically project a monochrome video frame with 1280 x 720 resolution. The phase-modulating device is expected to be a liquid crystal over silicon chip with silicon area similar to that of commercial devices. Its basic characteristics, such as number of pixels, bits per pixel, and pixel dimensions, are optimized in terms of image quality and optical efficiency. Estimates of the image quality are made from the noise levels and contrast, while efficiency is calculated by considering the beam apodization, device dead space, diffraction losses, and the sinc envelope.
  Applied Optics 10/2008; 47(26):4793-803. · 1.41 Impact Factor
• Source

  Available from: N. Collings

  Article: Aspects of hologram calculation for video frames

  A Georgiou, J Christmas, N Collings, J Moore, W A Crossland
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  ABSTRACT: This paper presents a modified version of the Fienup algorithm that can compute an image projecting hologram significantly faster. The proposed method, referred to as Fienup with don't-care (Fidoc), is sufficiently fast to enable real-time hologram calculation for video projection purposes. It achieves high speed and excellent image quality by dispersing noise in 'don't-care' areas around the image. Through simulations it was shown that for the same amount of computation, reconstruction quality is significantly better when using the Fidoc method instead of the simple GS (Gerchberg–Saxton) and Fienup algorithms.
  Journal of Optics A Pure and Applied Optics 02/2008; 10(3):035302. · 1.92 Impact Factor