We describe an electrooptic apparatus capable of displaying a computergenerated hologram in real time. Computer generated holograms have bean made practical. It is possible for a computer software to calculate the phase of light of an object. Hologram software ranges from free, downloadable programs to expensive programs. Given a mathematical description o a wavefront or an object represented by an array of f points, the computer can calculate the amplitude transmittance of the hologram and display the result on a crt or plot it on paper. It represents influence of all technological steps into quality of the final product. Hologram computers, mobiaq, illuminair, holographic. Computer generated holography and diffractive optical.
In computergenerated hologram cgh calculations, a diffraction pattern needs to be calculated from all points of a 3d object, which requires a heavy computational cost. Benefits of computer generated holography for nextgeneration. At that time, i was visiting professor toyohiko yatagai1 in japan. Algorithms take the target 3d intensity as input and compute the hologram that generates it. Software to make computergenerated hologram physics forums.
A line hologram with resolution of 4096x2730 occupies about 10 megabytes of hard drive spaces. Digital holography optically generates a hologram, which is then recorded on a ccd camera, and an image is reconstructed using digital techniques. Upon the proper recording, reconstruction, and viewing conditions, unlike the traditional 2d photography, the image appears to be 3d again. Fourier transform from a computer generated hologram phase mask. A portion of it encoding into fourier computer generated hologramcgh, while the. Computer generated hologram cgh eric logean august 2003 abstract this document is an introduction to the design and fabrication of computer generated hologram cgh as i understood them back in 1997. With luminit threedimensional computer generated holography, a predetermined image e. Index terms computer generated hologram cgh, fourier transformation, gerchbergsaxton algorithm. The new method is about 42 times faster than the conventional raytracing algorithm with approximately the same resolution. Computergenerated holographic techniques offer an efficient way for reconstructing holograms without complicated interference recording systems.
Fourier optics and computer generated hologram 3 computer generated holography is an optical numerical technique, which avoid the traditional light interference recording process by computer numerical calculation and record the hologram directly. Part of the reason is a simple tip of making hologram viewer with a cd case, and turning your smartphone into a hologram viewer. In old circuit cellar magazine they had a hobbyist cgi hologram project. Also initial picture, its hologram and reconstructed image are presented. The rainbow hologram is very practical to display 3d images because it can be reconstructed with white light. Each cell contains four equally spaced rectangular apertures. Computergenerated hologram cgh 1 includes a unique capability for recording and reconstructing the desirable amplitude and phase of object light, leading to a wide use of this technique in optical applications such as threedimensional 3d displays 2, projections 3. The course is geared towards scientists, engineers, managers, and researchers interested in exploring fundamentals of computer generated holography, diffractive optical elements, lcos arrays and maskless grayscale lithography who want to. We propose a simplified model to calculate the computer generated rainbow hologram quickly. Fourier transform from a computer generated hologram. Computergenerated holography constitutes an important branch of. The computergenerated hologram is calculated by a supercomputer, read from a. Burch suggested, then, that, in making computergenerated holograms, the amplitude transmittance o the hologram should be f because of the absence of the a2x, y term in tx, y in eq. We introduce a new algorithm for calculating computer generated hologram cgh using raysampling rs plane.
Rs plane is set at near the object and the lightrays emitted by the object are sampled at the plane. Digital recording and numerical reconstruction of holograms. The image is also cropped from the actual image due to its high resolution. Check out this simple tutorial of making hologram video with powerdirector. When sending the hologram to your printer, you want to reproduce it as faithfully as possible. Testing large optical elements can require the use of largesize cghs. Computergenerated holography cgh is the method of digitally generating holographic. Luminit computer generated holograms allow viewers to see clear, crisp, and bright holographic images without the need of glasses or other special eyewear.
Computergenerated holography cgh is the method of digitally generating holographic interference patterns. However, arbitrary patterns are generally infeasible, so solutions are approximate and often suboptimal. Numerical hologram reconstruction was initiated by yarosl avskii et al 11 at the early 1970s. This program allows you to create a transmission hologram using just a computer, a laserprinter, and an overhead transparency. The use of computer generated holograms for the testing of aspheric wavefronts is described. Then the lightrays are transformed into the wavefront with using the fourier transforms. Instead, as figure 1 shows, a computer calculates a holographic fringe pattern that it then uses to set the optical prop. For binary holograms, the length of the four rectangles is. This requires ensuring software and memory compatibility with the gpu structure, which is. The qr code generated is then converted into a hologram, thus providing a high profile security to the product. Note also how simple this pattern was to calculate this is the basis for the idea of computergenerated holography. Computergenerated holography is an emerging technology, made possible by increasingly powerful computers, that avoids the interferometric recording step in conventional hologram formation. Computergenerated holographic gratings in soft matter. The making of a computergenerated hologram features.
This is especially the case when characterizing large convex telescope mirrors. One of the first gray scale computergenerated hologram left and an image reconstructed from a gray scale computergenerated hologram right, adopted from 4 2 in sect. An analysis of the errors produced by emulsion movement, incorrect hologram size and position, and distortion in hologram plotter and photoreduction lens is given, and it is shown that all the errors are proportional to the slope of the aspheric wavefront. It started when jeff at ross roy communications found us through the internet. Miloth on 30 jun 2017 i am trying to perform a fourier transform of a phase mask to reconstruct my.
Hologram is a buzz word on internet world these days. Improvement of direct fringe printer for computergenerated holograms. This hologram will behave like one created using a laser, and can be. Osa calculation for computer generated hologram using.
The computergenerated hologram cgh is distinguished primarily from its optical cousin by the fact that the computer is able to design a hologram of a nonexistent, synthetic or virtual object, and the operation of the diffractive optical element doe can be. By implementing cgh calculations in a gpuprogram that is executed once per. Scaling of threedimensional computergenerated holograms with. In this paper, we propose a novel fast computergenerated hologram calculation method using sparse fast fourier transform.
You printed out your synthetic hologram as 300dpi laserprinter pages. As an alternative to the photochemistry and vibrationfree settings involved with regular holography, this program allows you to create a transmission hologram using just a computer, a laser printer, and an overhead transparency. Ive never seen a straightforward explanation of how computer holograms are actually transferred to the physical recording medium. A system includes a computer generated hologram cgh design plane and a processor capable of representing a three dimensional object. These computer generated holograms are then optically reconstructed. Holograms, holographic, 3d holography, computer generated. A computer generated hologram that could display a company logo in the lobby instead of a onedimensional sign is one example. The software also varies in the methods it uses to create holograms. Generation and replication of computer generated hologram. Download hologram effect software for windows for free. Trial software fourier transform from a computer generated hologram phase mask. The null testing setup using a customized computer generated hologram cgh in a mach zehnder interferometer is demonstrated in this video clip. In fact, the running time is proportional to the image width and height. Computergenerated hologram dainippon printing co ltd.
Holographic studios can transfer your 3d computer generated images into actual three dimensional holography displays. A photographically produced hologram is used to store and play back an existing wavefront. Software to make computergenerated hologram thread starter toan. Full parallax threedimensional computer generated hologram with occlusion effect using. Threedimensional or 3d software products generally allow users to construct holograms on a personal computer. We made software that simulates wave optics using previously known physical model to generate a hologram with the possibility of connection with commercial 3d. Computer generated fresnel hologram fabrication for true life scene 3d display duration.
Imagine seeing your 3d images in true holographic 3d. Vividqs software brings real time computer generated holography cgh to everyday applications. His company was designing the chrysler corporations information center at the mall of america. A computergenerated hologram with a complex amplitude of object light recorded therein so that a stereoscopic object is reconstructible, wherein. Computergenerated holograms cghs are diffractiveoptical elements that offer the possibility of creating waveoptical display systems that are under complete computer control. Realization of fourier and fresnel computergenerated holograpm. A hologram is an interference recording of a 3d surface. Improvement of direct fringe printer for computergenerated holograms duration. Optimization the running time of each computer generated hologram is different depending on the resolution of the image. Computergenerated hologram how is computergenerated hologram abbreviated. In my thesis, i implemented a computer program that is able to generate holograms. Synthetic holograms are specified by a computer and written with an electronic plotter. To drive these, computer generated holograms cghs, rendered from point. Here is the line hologram produced by the above phase function.
Clear, crisp, bright image with computer generated. Because cghs can control all aspects of the optical wave, threedimensional imagery can be presented to. It does not require the actual light and the actual. Computer generated hologram player cghplayer calculates and displays a hologram of an object consisting of point clouds in real time. This hologram will behave like one created using a laser and can be projected or viewed with a point source. Computergenerated hologram how is computergenerated. I also included in this document a short description of the. The wavefront on the cgh plane is calculated by wavefront propagation. Multiplane 4d cgh taking this concept another step forward, luminit is developing 4d multiplanar holography where different images could appear based on the position of the viewers eye.
Basically the function of a computergenerated hologram is to create an optical wavefront from a set of computed. The image position changes as the alignment of the viewing system changes. Computergenerated holograms for 3d imaging acm digital library. The phase of the aspheric wavefront is calculated at the center of each cell. Us7649532b2 computer generated hologram display system. We used a laser which shined through a beam expandercollimator a photographed cameras lens into the computer generated hologram. The processor is configured to represent a surface of the three dimensional object by a facet, impose a grid defining a set of nodes upon the facet, and associate object points with each node of the grid. Pdf computer generated fourier holograms for ug laboratory. Some enable users to layer any photograph, creating a 3d effect. Computergenerated holograms for optical testing usually consist of patterns of curved lines drawn onto or etched into glass substrates.
Introduction computergenerated holograms, synthetic holograms and computer holograms are terms used to refer to a class of holograms which are produced as graphical output from a digital computer. A computer generated hologram or a cgh is a computed interference pattern of such 3d scene. The final photoreduction step could, of course, be eliminated by using special output devices to write the hologram directly in the desired size. Computer generated hologram construction kit freecode. However, since the amount of calculation is very large, the fps becomes very low as the number of points of the object increases. A fast method that allows holograms to be efficiently generated by computer is described. In this work, holographic barcodes using computer generated holograms are.