Modifying pixel values to improve iterative process for holographic display

摘要

A method of projecting alpha-numeric characters on a screen comprises receiving a frame of alpha-numeric characters (figure 2) defined as intensity varying pixels 101, modifying the pixel values to enhance a subsequent iterative process 102 and modulating a light source to produce an interference signal 103. Thus the alpha-numeric characters can be displayed on a screen and the screen and projector may be placed a long way apart. The iterative process may take the form of a repeated Fourier transform process for a predetermined number of iterations or until a detected error threshold is reached. Modification of the pixels may involve applying a high pass filter to the source image or edge sharpening of the image. The light source may be a laser and the moderator may use phase responsive liquid crystals. Only a part of the display may be used, avoiding using the origin or centre of the display (figure 16).