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A Study of Image Stereography Display and Techniques Harsh Pratap Singh Assist. Professor SSSUTMS, Sehore ABSTRACT Stereographic image is the art of interpretation of 3-d image by combing the pair of 2-d image. It is widely used area of transmission, storage and standardization matters associated to stereo imaging. The stereography is a method to produce stereographic video, images and films. The stereography method uses different equipment to form images such as, stereo camera, and single camera with or without any attachment and different technique also comprises to develop stereo image. This paper, discusses about the overview of stereography techniques and different kinds of photography to form stereo images. Keywords Setereography, Video, stereo image, photography, camera 1. INTRODUCTION One of the most astonishing properties of the human vision system is its capability to undergo the depth of the scenes being viewed. Stereography is the knowledge (typically) of rendering a 3-d image in the mind of the viewer by using a pair of 2-d images. The word "stereo" instigated from the Greek and meaning is that "relating to space". Nowadays, as we talk about stereo, we generally refer to stereophonic sound. At first, the term was connected with stereoscopic pictures, which were either strained or photographed. In order to evade confusion with stereophonic sound, one at present often talks about 3D pictures and particularly 3D-film, where 3D, of course, stands for threedimensional. This is made probable by a process named stereopsis. The procedure takes benefit of the binocular nature of human vision - each eye perceives a slightly dissimilar 2-dimensional image, and the brain uses the differences to renovate the third dimension, regularly called depth. Stereography impersonates this process. By "tricking" each eye into viewing a different image, where each image corresponds to the same scene but from somewhat dissimilar angles, the brain will rebuild the third dimension just as in normal binocular vision. There are numerous ways of accomplishing it. This easy geometrical arrangement has significant consequence: because the world shows dissimilar from any of these viewpoints, the image we distinguish of the world is never recorded straight by any sensory array, but constructed by our neural hardware. On the other hand, it is probable to motivate our sense of stereo vision synthetically by acquiring two pictures of the same scene and afterward presenting the left image to the left eye and right image to the right eye, consent to the brain to mingle them mutually for three-dimensional Rashmi Singh Assist. Professor RITS, Bhopal (3D) perception. The skill and science of capturing, storing, editing, transmitting and exhibiting such ‘still’ and ‘moving’ images is defined as stereo imaging. [1] The most primitive interests in stereo imaging were directed on stereo photography. The invention of the first binocular camera by Sir David Brewster in 1949 resulted in a gigantic trade in stereoscopes and stereo images. The initiation of London Stereoscopic and Photographic Company in 1850 and the growth of the Stereoscopic Society in 1893 are considered two untimely milestones in stereo imaging. as a result, with the 3D movie craze of the early 1950’s and the wonder of holography in the 1960’s, the excitement about the feeling of depth and reality grew exponentially, leading research teams around the world to explore the possibilities of making free viewing, “ultimate 3D experience” systems. After the rapid development of the computer graphics industry in the 1990’s, there was a general realization that the two-dimensional projections of three-dimensional scenes, traditionally referred to as "three-dimensional computer graphics", are insufficient for inspection, navigation, and comprehension of some types of multivariate data. For such data, the often neglected human depth cues of stereopsis, motion parallax and to a lesser extent, ocular accommodation, are essential for an image understanding. In this paper, we present the literature study of image stereography techniques and its types. The organization of the remaining section is arranged in this way: Section II discusses about the literature work. In section III discusses about the image display of stereoscopy and Section IV present types of image stereography & different techniques of stereography and last concludes the whole paper. Fig. 1 Image stereography process 1 2. RELATED WORK Chuang et al [2] proposed a novel projection model for mapping a hemisphere to a plane. Such a model can be functional for viewing wide-angle images. Their model consists of two steps. In the initial step, the hemisphere is anticipated onto a swung surface constructed by a spherical profile and a rounded rectangular trajectory. The subsequent step maps the projected image on the swung surface onto the image plane throughout the perspective projection. They also proposed a method for robotically determining proper parameters for the projection model based on image content. The proposed model has numerous advantages. It is uncomplicated, proficient and simple to control. Most prominently, it makes a better conciliation among distortion minimization and line preserving than accepted projection models, such as stereographic and Panini projections. Experiments and analysis make obvious that the effectiveness of their model. Antoine et al. [3] oppressed the continuous wavelet transform (CWT) on the two-dimensional sphere S2, introduced formerly by two of us, to fabricate associated discrete wavelet frames. They initially explore half-continuous frames, i.e., frames where the position remnants a continuous variable, and then move on to a fully discrete theory. They introduced the notion of controlled frames, which reflects the scrupulous nature of the underlying theory, in scrupulous the apparent divergence between dilation and the compactness of the S2 manifold. They also highlight some implementation issues and present numerical illustrations. Sochan et al. [4] offered a tool for online compression and streaming of stereoscopic video and images and contemplation on adaptation of the video stream to network conditions. The software consent to to use dissimilar encoding schemes for video compression and streams the stereo frames using UDP protocol. They give measurements of the frame delays in the transmission for diverse codec configurations. Hwang et al. [5] anticipated a novel directional backlight system based on volumeholographic optical elements (VHOEs). Now, VHOEs are employed to organize the direction of light for a time-multiplexed display for each of the left and the right view. Those VHOEs are fabricated by recording interference patterns among collimated reference beams and diverging object beams for each of the left and right eyes on the volume holographic recording substances. For this, self-developing photopolymer films (Bayfol HX) were used, since those abridge the manufacturing process of VHOEs substantially. At this time, the directional lights are analogous to the collimated reference beams that were used to record the VHOEs and create two diffracted beams analogous to the object beams used for recording the VHOEs. Subsequently, those diffracted beams read the left and right images alternately exposed on the LCD panel and form two converging viewing zones in front of the user's eyes. By this he can distinguish the 3-D image. Speculative predictions and experimental consequences are presented and the performance of the developed prototype is exposed. Chen et al. [6] developed a beam splitter based on a holographic optical ingredient in polymer dispersed liquid crystals (PDLC) to engender a stereogram. To engender a stereogram on a liquid crystal panel, a beam splitter is principally required to direct the image on odd pixels to reproduce to right eye, and direct the image on even pixels to disseminate to left eye of the spectator. The commercial method to stimulate the obligatory beam splitter is using a barrier or a ventricular array. The former method may lessen the brightness of the stereogram, and the later method may stimulate more cross talk noise. Instead of that, they proposed a novel technology for a beam splitter based holography. The whole beam splitter is a holographic optical element composited of plentiful sub-holograms attached on each column pixels. The odd column pixels are marked with R and even column pixels are marked with L. The sub-holograms above the odd column pixels will diffract the images revealed on R column pixels to proliferate to right eye, and subholograms above the even column pixels will diffract the images shown on L column pixels to proliferate to left eye. They find these two images can be separated successfully. The diffraction effectiveness for each image is about 40% in our experimental element, and consequently the brightness of the stereogram is about 40% of the original brightness on panel. The brightness performance is much superior to the barrier technology, which produce stereogram with low brightness only 23% of the inventive brightness on panel. Feng et al. [9] developed a method for extending existing image warping algorithms to stereoscopic images. This technique divides stereoscopic image warping into three steps. Our method first applies the user-specified warping to one of the two images. Our method then computes the target disparity map according to the user specified warping. The target disparity map is optimized to pre-serve the perceived 3D shape of image content after image warping. Their method lastly warps the other image using a spatiallyvarying warping method guided by the target disparity map. The experiments demonstrated that their technique enables existing warping methods to be efficiently applied to stereoscopic images, ranging from parametric global warping to non-parametric spatially-varying warping. 3. STERIEOSCOPIC IMAGE DISPLAY Stereo vision developed hundreds of millions of years before in invertebrates as a significant survival method. The primary definitive manifestation of stereovision in insects was just accomplished by a Swiss researcher who glued minute prisms to the eyes of a praying mantis, which then missed its quarry by precisely the 2 calculated quantity. Humans have become so genetically deteriorate that severe visual problems including loss of stereo perception are common [7]. The immense majority has good depth perception but sophisticated tests show broad variations. The individual variations in stereovision should be of imperative concern in the creation and use of stereo systems but are typically completely ignored. As with every one other physiological system, stereovision may recover swiftly with use, both short term and long term. Repeated use of a stereo display can lead to more express fusion and larger comfort. Apart from for a only some persons who practice frequently with a wide assortment of stereo displays and images, it is not probable to appraise a stereo display system or image by casual examination. As with any other parameter, a haphazardly selected individual may be numerous standard deviations from the mean in either direction including perhaps 10% who have severe problems with stereo under whichever conditions and 10% who qualify as stereo prodigies due to their quick, prolonged and comfortable fusion of images which may be unpleasant or impracticable for the average person, or to their other abilities such as making very excellent depth determinations. Discrepancy with age is to be expected as is a circadian rhythm. Evaluation by a battery of users with recognized stereovision abilities using the hardware and software precisely as it will be employed by the end user is essential. This should include frequency and duration of use, similar imagery, ambient illumination, viewing distance and exactly the same monitor. The latter is indispensable since in the dominant field sequential method the exact hues and saturations of the images, contrast and brightness and the different persistence’s of different phosphors are very important. Also, the same hardware and software may yield dramatically different results if the color of figure and background are altered. Long persistence green phosphors are a general problem. Screen size and viewing distance, horizontal and vertical parallax, binocular asymmetries (enlightenment etc.) and nonstereo depth cues are critical. Most stereo displays and images are created and used with little attention to these factors even when highly skilled personnel are involved. A vital component of a stereo project should be a stereoscopist having extensive experience with many systems and images. This is rarely considered necessary, resulting in defects in hardware, software, viewing conditions and viewers and less than optimal images that are regarded as natural restrictions of electronic stereoscopy or of field sequential input or head mounted displays. It is still said that these are unnatural ways to look at images (as though 2D CRT'S, photos, and books grew on trees). This conveys to mind the classic experiments with prism glasses performed three generations ago. As soon as one initial puts on glasses which turn the visual world upside down, it is nearly impracticable to function. Following a few days subjects learn to navigate and the world progressively appears more or less normal. The key phrase in the advancement of most organic systems is "plasticity equals survival". There is even some current substantiation that many strabismus (cross eyed) subjects have some depth perception due to a type of field sequential commencement of the optic pathways by the reticular activating system in the brain stem. 4. TYPES OF IMAGE STEREOGRAPHY There are copious ways to accomplish the process of image stereography: 4.1 Anaglyphic Stereography Anaglyphic stereography [8] is the category used in 3-d movies: each image is presented in a unusual color, and colored filters in front of each eye consent to only the suitable image to pass. Some international standards body has decided that the right eye filter should be blue, while the left eye filter is red, but this can be different. For example, the image below requires the red filter over the right eye. These images can be produced using just about any graphics program - just coalesce the blue and green channels of the left image with the red channel of the right image. It is probable to use other colors, but cyan and red, being complementary colors, produce a truecolor image in the mind of the viewer. The subject of the images should be coincident on the image (as in the dragonfly nymph's head in the above image) to make the image easier to view. Fig. 2 Anaglyphic Stereogram of a Dragonfly Nymph One problem with true color anaglyphs is that any item that happens to be the same color as either filter will only be visible to one eye. Try viewing the above cyan and red images above through anaglyph glasses and you'll see why this is a problem. Fig. 3 True Color Anaglyphic Stereo 3 4.2 Orthostereography Orthostereography uses images presented side-by-side. This kind of stereography goes back a long time, and was quite popular around the turn of the 19th century. Orthostereographs have a distinct advantage over anaglyphic stereographs - many stereographs may, with sufficient practice, be viewed without special equipment. Fig. 4 An c.1900 Orthostereogram Methods A. Autostereoscopy This display technologies use optical components in the display, rather than worn by the user, to enable each eye to see a different image. Because headgear is not required, it is also called "glasses-free 3D" [10]. The optics split the images directionally into the viewer's eyes, so the display viewing geometry requires limited head positions that will achieve the stereoscopic effect. Automultiscopic displays provide multiple views of the same scene, rather than just two. Each view is visible from a different range of positions in front of the display. This allows the viewer to move left-right in front of the display and see the correct view from any position. The technology includes two broad classes of displays: those that use head-tracking to ensure that each of the viewer's two eyes sees a different image on the screen, and those that display multiple views so that the display does not need to know where the viewers' eyes are directed. Examples of autostereoscopic displays technology include lenticular lens, parallax barrier, volumetric display, holography and light field displays. B. Holography Holography is a technique that is used to display objects or scenes in three dimensions. Such three-dimensional (3D) images, or holograms, can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. The concept of 3D telepresence, a real-time dynamic hologram depicting a scene occurring in a different location, has attracted considerable public interest since it was depicted in the original Star Wars film in 1977. However, the lack of sufficient computational power to produce realistic computer-generated holograms1 and the absence of large-area and dynamically updatable holographic recording media2 have prevented realization of the concept. Here we use a holographic stereographic technique3 and a photorefractive polymer material as the recording medium4 to demonstrate a holographic display that can refresh images every two seconds. A 50 Hz nanosecond pulsed laser is used to write the holographic pixels5. Multicoloured holographic 3D images are produced by using angular multiplexing, and the full parallax display employs spatial multiplexing. 3D telepresence is demonstrated by taking multiple images from one location and transmitting the information via Ethernet to another location where the hologram is printed with the quasireal-time dynamic 3D display. Further improvements could bring applications in telemedicine, prototyping, advertising, updatable 3D maps and entertainment 5. CONCLUSION The stereography is extensively use technology which measures the depth and perspective of image in respect to 2D or 3D environment. This technology is used in many application areas such as Simulator, CAD, endoscopic surgery and remote control vehicle tec. In this paper we present types of stereography, method and literature of the stereography. To provide higher definition and eminence, information redundancy removal of the large amount of resulting data is the major issues. So in future work, design such technique and tools which will provide better quality of image and able to remove the redundancy easily from the large set of information. REFERENCE [1]. E. A. Edirisinghe, J. Jian, “Stereo Imaging, an Emerging Technology”, http://www.ssgrr.it/en/ssgrr2000/papers/067 .pdf Fig. 5 Parallax barrier autostereoscopy to display a 3D image [2]. Che-Han Chang, Min-Chun Hu, Wen-Huang Cheng and Yung-Yu Chuang “Rectangling Stereographic Projection for Wide-Angle Image Visualization”, supported by grants NSC101-2628E-002-031- MY3 and NSC102-2622-E-002-013CC2. [3]. I. Bogdanova, P. Vandergheynst, J-P. Antoine, L. Jacques b and M. Morvidone, “Stereographic wavelet frames on the sphere”, Applied and 4 Computational Harmonic. Analysis 19 (2005) 223– 252. [4]. Krzysztof Grochla, Arkadiusz Sochan, “Adaptive Streaming of Stereographic Video”, Communications in Computer and Information Science, 16th Conference, CN 2009, Wisła, Poland, June 16-20, 2009. [5]. Hwang YS, Bruder FK, Fäcke T, Kim SC, Walze G, Hagen R, Kim ES “Time-sequential Autostereoscopic 3-D display with a novel directional backlight system based on volumeholographic optical elements”, 2014 Apr 21;22(8):9820-38.doi: 10.1364/OE.22.009820. [6]. Wei-Chia Su ; Nat. Changhua, Changhua, ChienYue Chen ; Hsin-Wei H, “Autostereoscopic display using a holographic splitter in polymerdispersed-liquid crystals-May 2011, Print ISBN: 978-1-4577-0533-5. [7]. Reginald L. Lagendijk, Ruggero E.H. Franich and Emile A. Hendriks, “Stereoscopic Image Processing”, supported by European Union under the RACE-II project DISTIMA and the ACTS project PANORAMA. [8]. http://www.3dglassesonline.com/ourproducts/anaglyphic. [9]. Yuzhen Niu Wu-Chi Feng Feng Liu, “Enabling Warping on Stereoscopic Images”. [10]. Dodgson, N.A. (August 2005). "Autostereoscopic 3D Displays". IEEE Computer 38 (8): 31–36. doi:10.1109/MC.2005.252. ISSN: 0018-9162. [11]. S.A.Benton, “The second generation of the MIT holographic video system.”, TAO First Int. Symp.,1993. [12]. P.-A. Blanche, A. Bablumian, R. Voorakaranam, “Holographic three-dimensional telepresence using large-area photorefractive polymer”, Nature 468, 80–83 (04 November 2010). 5