Recent developments in a new method of holographic computer-aided imaging are reviewed. The proposed hologram is computed from angular viewpoints of the observed three-dimensional scene. The recorded data are processed to yield a two-dimensional computer-generated hologram. When this hologram is illuminated properly, a three-dimensional image of the scene is reconstructed.
It is discussed a 3-D pattern recognition technique in which, the holograms of objects is recorded as a form of electric signal and 3-D pattern recognition by digital processing of the holograms is achieved. In this technique, is not necessary to record a series of 2-D images for representation of a 3-D object because the holographic information of the object is utilized.
At this chapter the method of 3-dimensionl image reconstruction, based on the acoustooptical interaction of reference light beam at the hologram that created by high frequency acoustic wave field, is discussed. Such, acoustically created hologram is electronically controlled and as a sequence the moving bulk scene reconstruction is possible. The mathematical modeling of step-by-step image capturing and reconstruction is discussed. The architecture of such king of system is considered.
A method for synthesizing computer-generated holograms of real-existing objects is described. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD camera. According to the principle of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel computer-generated hologram(CGH) is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary for recording. The use of a color CCD in recording enables us to record and reconstruct colorful objects. Finally, we demonstrate color reconstruction of objects both numerically and optically.
The peculiarities of the development of various steereodisplays are analyzed. The new variant of parallax barrier with the neural network information processing and stereoadapter for the usual display is described. The influence of functionality of the optical elements of stereodisplays on the parameters of stereo information human perception is considered.
The principles of design, the basis of functioning and characteristics of 3-dimensional (3D) visual information systems synthesis and analysis are analyzed. In the first part of paper the modern state of 3D video information synthesis and reproduction systems development is considered, like: stereoscopic, auto-stereoscopic, and holographic. In the second part the principles of machine-vision systems are considered, that the analysis of 3D video-information are realized.
The main principles of various glasses-based stereoscopic systems and their significances are discussed. Practical results of developed and produced by Russian companies original ready-to-use stereoscopic add-ons (attachments) to standard computer and television displays are described.
Stereo-glasses with PDLC shutters are compared with glasses based on other electro-optic modes in nematic LC. The PDLC glasses provide high speed of response as well as low fatigue of operator’s eyes. Additionally a method of writing dynamical pictures with non-compact scenes for the purposes of information displaying or holography is described. Each section of a non-compact scene is registered by an independent TV camera and projected onto a multilayer PDLC screen. The success of driving pulses to change the PDLC layer transparency is selected in accordance with the section number.
Requirements to the volumetric displays and their features in comparison with 2-D screen based 3-D displays are considered. The main difference of a volumetric display is a possibility to look around displayed 3-D object by many observers from other sides simultaneously, and no points of view are calculated for this. Optical, optical-mechanical and optical-electrical methods of addressing the voxels in a volumetric media are discussed. Basic features, advantages and disadvantages of concrete volumetric display developments on the base of the two-photon absorption, rotating helix or disc, light scattering in liquid crystal shutters are presented. Problems and prospects of volumetric displays are discussed.
The paper is devoted to the method of 3D image reconstruction by means of volumetric display application. The problems of syntheses and coding of 3D images are considered. Peculiarities of volumetric image creation are discussed.
Moire patterns originated from overlapping display panel with the viewing zone forming optics are one of major factors of deteriorating the visual image quality of contact-type 3 dimensional imaging systems. An analysis showed that the visual effects of the patterns can be minimized at a specific overlapping angle between the panel and the plate. This angle is implemented by approximating each side of a pixel cell as a discrete line which is drawn along the boundaries of each pixel which lies along the side of the cell. The slope of the line is presented by as the ratio of pixel numbers in vertical and horizontal directions and equals to the tangential value of 1/2 of the angle. This method allows creating pixel cells with shapes of parallelograms and rhombs with a desired vertex angle for minimizing the moire pattern, especially in full-parallax imaging systems. The image generated reveals almost invisible moire pattern at the predefined viewing distance range.
General method is suggested for construction of the non-lens digital microscopes of optical range. This article demonstrates that non-lens microscopes of average magnification can be created on the basis of inexpensive digital cameras. Only disadvantage of the camera that is considered, as a candidate for this application is - that such camera still has the objective.
De Montfort University (DMU) has developed an autostereoscopic display that is targeted specifically at television applications. The display is capable of supplying 3D images to multiple viewers who are not required to wear special glasses, and who are able to move freely over a room-sized area. It operates by producing regions (exit pupils) in the viewing field where either a left or a right image is seen. The positions of the exit pupils are steered to the viewers’ eyes by the use of head tracking. The DMU display consists of an LCD whose conventional backlight is replaced by a steerable optical configuration that is capable of producing several pairs of exit pupils. Left and right images are produced on alternate pixel rows of a single UXGA LCD. This spatial image multiplexing is achieved by the use of a lenticular sheet located between the steering optics and the LCD. The steering optics can produce exit pupils over a large area, but without the aberration and coloration effects associated with other methods. This is achieved using arrays of coaxial lenses in conjunction with high-density white LED array sources.