RU2526901C1 - Three-dimensional display and method of forming three-dimensional images - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: device includes an optical system consisting of a fixed part which includes a multi-faceted projector and a mirror polyhedron, and a mobile part which consists of a projection optical system and a screen.

EFFECT: enabling reproduction of full-colour three-dimensional panoramic images in real time without using ultra-high speed data processing and high-speed projection means, without using individual stereoscopic viewing means.

13 cl, 10 dwg

Description

The group of inventions relates to means of displaying information and can be used to display full-color three-dimensional objects and scenes, observed round-the-clock without the use of individual visualization tools. The inventions can be used, in particular, in navigation systems, machine design and construction, for visualizing tomographic information and performing complex operations in medicine, for modeling three-dimensional problems in science and technology, in computer simulators and games, in art, advertising, and entertainment etc.

The development of systems for three-dimensional display of the real world significantly affects all spheres of human activity and initiates the creation and development of a number of scientific areas and technologies. Therefore, attempts to develop effective autostereoscopic displays have not stopped for many years.

The prior art single-angle autostereoscopic displays with a parallax barrier, using, for example, a vertical band-pass polarizing filter [1-3], as well as displays with a lens raster filter [4, 5]. The optical filters of these devices (parallax barrier or raster lens) are used for spatial separation of stereo pairs in the zones of vision. The observer can see a stereoscopic image only when both his eyes are located in the corresponding zones. The width of each of the zones does not exceed the interpupillary distance, while the shift of the eyes relative to the center of the zone by two or more centimeters leads to a significant distortion of the observed image. If the viewer changes position and leaves the zone of vision, the stereo effect is inverted or lost. Strict fixation of the position of the head relative to the zones of vision usually causes a feeling of discomfort and rapid fatigue of the viewer, so the main disadvantage when using these devices is the need to immovably hold the head of the viewer in areas of selective stereoscopic vision.

Known multi-angle autostereoscopic displays [6], in which visibility zones are formed by reproducing six or more angles of a single three-dimensional scene. Moreover, all adjacent images of this group form stereo pairs, and the separation of angles into visibility zones is carried out using, for example, an inclined lens raster. When the angle of the raster is about 10 degrees, it becomes possible to separately reproduce up to nine angles of the object. In this case, the resolution of each angle is reduced horizontally and vertically by three times ^{(Tilted lens raster is used in SynthaGram displays of the American company StereoGraphics, 3DWOW displays of the Dutch company Philips and similar displays of other companies, for example SuperD (HDL-46))} . However, a multi-angle method of image formation requires the use of powerful computing tools, significantly reduces the resolution of a single image and does not provide a full viewing angle of the scene being demonstrated [7].

Also known are methods and devices for creating a volume holographic image using coherent laser radiation [8]. A hologram is the most advanced, but relatively complex way to obtain an autostereoscopic image. Despite the abundance of patents ^{(for example, US patents Nos. 4,359,758 and 4,484,4219 or RF patent No. 215148)} , the practical implementation of the holographic display is fraught with many technical difficulties and, first of all, with the solution of the problem of high-speed data processing, fast recording and erasing of holograms on volumetric environments. This problem is only partially solved, the processing of one frame of a holographic image requires heavy-duty computing tools and time-consuming (about 8 min per frame), which significantly complicates the output of a moving image ^{(The data stream required to recreate a full-fledged image using the holography method reaches about 1 Tb / s (1012 bits per second). It is not yet known how to store and even transmit such an amount of information)} . Moreover, if this problem is successfully solved, nevertheless, the holographic method will remain at the stage of laboratory experiments for a relatively long time. Well-known holographic displays so far reproduce only a monochrome image and, like multi-angle displays, do not provide a circular view of the objects of demonstration ^{(The dimensions of the equipment serving the topography are huge compared to the dimensions of the generated image, and the need to use lasers for shooting and demonstration introduces additional inconvenience and makes playback difficult biological objects)} . Based on these shortcomings, we can conclude that holographic displays in the classical sense, i.e. using the phenomenon of interference on diffraction gratings, they do not have real prospects for wide distribution, including and in the rather distant future.

Devices based on the optical-mechanical principle, the so-called volumetric displays, in which radiation scattering by rapidly moving bodies is used to display data, are deprived of these disadvantages [9]. If the light-scattering body moves with a frequency exceeding the frequency of light flickers visible for a person, and the scanning of radiation is synchronized with the movement of the body, then for the observer averaging of successively illuminated points takes place and from their combination a volumetric image is formed. A quick scan by the initiating beam of a two-dimensional plane allows you to form a luminous point in a given place of the light-scattering body, which provides two coordinates, and the movement of the light-scattering body itself provides the third coordinate of the generated light model of the demonstration object. The movement of the body can be reciprocating, which is realized much more difficult [9, 10], or rotational [11]. The light layout thus formed has all the visual characteristics of a real three-dimensional image and therefore does not require the use of individual means and does not limit viewers in choosing the observation position. In this case, there is no eye and nervous fatigue inherent in the use of stereo glasses, as well as image jumps, often accompanying the movement of viewers relative to autostereoscopic displays, i.e. The most realistic perception of the object of the demonstration is achieved.

The volumetric category also includes the color surround display known from the prior art (Patent RU 2111627 C2, class H04N 9/31, G09G 3/06, publ. 05/20/1998), containing a laser, a scanning unit and modulation of laser radiation, and also a visualizer, which is a body of complex shape with the possibility of rotation around its axis. The display visualizer is made in the form of a set of plates mounted obliquely to a plane perpendicular to the axis of rotation, the number of plates being a multiple of the number of primary colors of the colorimetric system used and each of the plates coated with a substance that converts the laser infrared radiation into visible radiation of one of the primary colors of the colorimetric system used.

The main condition for the successful operation of the volumetric display is the high speed of output and visualization of images of sections or projections of the object. If the visualization time of one section is t, then for high-quality reproduction of a three-dimensional image of an object (scene), the relation t * N≤1 / 25 seconds must be satisfied, where N is the number of sections displayed per revolution of the visualizer. The larger the number of sections used to reproduce the object, the more reliable and voluminous this object appears to the observer, but the faster these sections must be formed and displayed on the visualizer. And vice versa, the known value of the visualization time of one section sets the limit of the number of displayed sections of the object N, which determines the achievable quality of the visualization of the volume of the scene using this display when working in real time.

The main disadvantage of the display (patent RU No. 2111627) is the lack of speed of the image forming apparatus. Indeed, with a laser beam positioning time of about 0.4 μs ^{(The standard laser beam scanning system allows you to project from 30 to 60 thousand dots per second (kpps), the high-precision precision system has a productivity of 1.5-1.8 times higher (www.x-light.ru) )} in 1/25 of a second you can only visualize about 100 thousand points. Given that in order to obtain the required color, the infrared laser beam should highlight the points "... sequentially on each plate, the number of which is a multiple of the number of primary colors of the colorimetric system used ..." (i.e., in RGB there are at least three points on three plates) the number of colored dots for one revolution of the visualizer does not exceed 34 thousand. This is suitable, for example, to indicate the position of aircraft in the specified echelons of the controlled air zone, but it does not provide visualization of a single slice of a standard full-color image, where the minimum requires about half a million pixels (800 × 600).

A significant breakthrough in the creation of volumetric systems was made during the development of the Perspecta Spatial 3D display ^{(the first commercial version of the real-time three-dimensional display Perspecta Spatial 3D Platform with a three-dimensional screen was demonstrated in 2002 by the American company Actuality Systems, Inc. (www. actuality-systems.com). The display used a light-scattering disk screen with a diameter of about 25 cm, which rotated at a speed of 25 r / sec in free space inside a transparent hemisphere 50 cm high)} . From the description of this invention (Patent US 6554430 B2, class G03B 21/28, G09G 5/10, publ. April 29, 2003) a three-dimensional three-dimensional display is known, including transmitting optics with transfer lenses and field lenses, an engine, and a support structure ( platform) connected to the engine, a flat projection screen located on the support structure so that the axis of rotation lies in its plane and the projection lens is located on the axis of rotation so that the axis of the lens makes an angle from 4.9 ° to 5 ° with the axis of rotation. During operation of the display, the transfer lens receives the light beam from the light source and transmits the light beam to the field lens, the field lens transmits the light beam to the projection lens, which projects the light beam onto the projection screen, the engine rotates the support structure, the projection screen and the projection lens around the axis of rotation .

The device may also include three additional mirrors mounted on a support structure so that the first mirror receives a light beam from the projection lens and directs the light beam to the second mirror, the second mirror directs the light beam to the projection screen or third mirror (if any) which directs a ray of light to the projection screen.

Along with such an undoubted advantage of this solution, as the use of visible radiation, this device also has disadvantages. The main one is (as in the previous case) the need for a high speed of formation and output of the image of the sections of the object of the demonstration. With insufficient speed of this process, the quality of the resulting display sharply decreases due to a decrease in the number of displayed sections or a decrease in the coloristic characteristics of images.

Perspecta Spatial 3D displays the cross-sectional image of the displayed object on the basis of a DLP digital three-chip video projector from Texas Instruments, Inc. [12], the fastest existing currently (performance up to 22 Gb / s). The video projector is based on a microdisplay, which is a matrix of light deflectable micromirrors (DMD) operating in a binary system. The gray scale and, accordingly, the shades of colors in the images are provided by the repetition of deviations with different frequency and duty cycle. The projector is capable of real-time output of up to 1000 full-color images in the format of 1024 × 748 pixels per second. However, in relation to the described device, one revolution of the projection screen (at a rotation speed of 25 rpm) accounts for only 40 full-color sections of the object, which does not allow to obtain its high-quality volumetric layout. Therefore, the developers of the device had to abandon the grayscale, which requires a lot of time, respectively, and from color shades, requiring 24 bit representation, and reduce the generated image of the object sections to a 6 bit scheme (three primary, three additional colors plus white and black). This made it possible to increase the output speed by three times and get up to 198 sections of the object in one revolution ^{(In another modification two series of sections are displayed, 198 sections in each, while the output image is reduced to a 3-bit scheme)} at a rotation speed of the projection screen of about 900 rpm / min

For the validity of the presentation, we estimate the output speed that a system for generating a high-quality volumetric full-color image of an object must use when using the above-described optical system scheme of the device.

The average visual acuity of the human eye is approximately one angular minute. When the observer is removed at a distance l from the center of the three-dimensional scene, the necessary resolution of the image output system δ can be calculated according to the expression:

. $$\delta =l\cdot Sin\left(\frac{2\cdot \pi }{360\cdot 60}\right)$$

.

We limit the playback region of a three-dimensional scene to a cylinder of height h and radius r and determine the number of diametral sections of the cylinder N, which is necessary for the continuous perception of scene objects from any azimuthal direction during a circular view of the scene:

. $$N=\frac{2\pi r}{\delta }$$

.

Define the number of planar image units (pixels) k that fit on the area of one diametrical section of the cylindrical playback area:

. $$k=\frac{2\pi r}{\delta }$$

.

векселей.The number of volumetric units of the image (bills) m that make up one frame of a three-dimensional scene in this case is equal to: $$m=k\cdot N=\frac{2\mathrm{<figure-callout\; id="2"\; label="r\; h\; \delta "\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">r\; </figure-callout>}h}{{\delta }^{}}\cdot \frac{2\pi r}{\delta }=\frac{\mathrm{four}\mathrm{<figure-callout\; id="2"\; label="\pi \; r"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">\pi \; </figure-callout>}{r}^{}{}^2\cdot \mathrm{<figure-callout\; id="3"\; label="h\; \delta "\; filenames="00000012.png,00000013.png"\; state="\{\{state\}\}">h\; </figure-callout>}}{{\delta }^{}}=\frac{\mathrm{four}\mathrm{<figure-callout\; id="2"\; label="\pi \; r"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">\pi \; </figure-callout>}{r}^{}{}^2\cdot h}{{\left(l\cdot Sin\left(0.000291\right)\right)}^3}\approx 5.1\cdot {10}^{\mathrm{eleven}}\cdot \frac{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\cdot \mathrm{<figure-callout\; id="3"\; label="h\; l"\; filenames="00000012.png,00000013.png"\; state="\{\{state\}\}">h\; </figure-callout>}}{l^{}}$$

bills.

Let the playback region of the three-dimensional scene have dimensions r = 0.1 and h = 0.2 m. Let us take the distance from the center of the playback volume to the observer l = 1 m (the allowable interval in this case is δ≈0.0003 m), then the number of bills in one frame of the scene is m = 1.021 · 10 ⁹ bills.

At an image output rate of 25 frames / second, the output volume will be 2.55 · 10 ¹⁰ bills per second ^{(The maximum DLP output rate of the projector is 766 Mpixels / sec, which is approximately 30 times lower than the obtained value)} . For a standard 24-bit image, the output system performance should be at least P = 24 · 2.55 · 10 ¹⁰ = 612 Gb / s.

Such a speed of data output with the current level of technology is unattainable and it is not known whether it will be achieved in the near future. For comparison, we recall that the ultimate performance of the fastest of the existing three-chip DLP projectors is about 22 Gb / s, which is ten times less than the calculated value. This assessment was carried out for a very modest-sized cross-sectional area of the reproduction region of three-dimensional objects (a total of 660 × 660 pixels). With an increase in the size of this region, the required image output rate increases in proportion to the third degree of its size.

As follows from the analysis, the main difficulty in creating 3D round-robin displays is that without special measures, displaying three-dimensional scenes even of a small size requires too high information display speeds that are not yet available to modern technology.

In addition to the above drawback, which is typical of existing volumetric display models, the solution according to US patent No. 6554430 has a number of disadvantages, which include, first of all, stringent performance requirements for the graphics processor and data storage and transmission systems. The latter is further complicated by the fact that, to construct an image of a three-dimensional model of an object, the device under consideration displays a sequential series of its two-dimensional azimuthal sections, which assumes the presence of a mathematical model of the object and data processing “per pass” for calculating the current sections of the demonstration object ^{(Performance of the fastest of modern graphic processors does not exceed 76.8 Gb / s, which is an order of magnitude less than the required output performance, not taking into account additional data processing x at passage).}

Additional machine power is also needed to compensate for the scale distortions and optical aberrations introduced by the projection display optics (for example, due to the non-perpendicularity of the optical axis of the system and the plane of the projection screen ^{(Partially scaled distortions and image defocusing arising due to the non-perpendicularity of the screen to the incident light flux are compensated by 5 ° deviation (according to the Scheimpflug principle) of the lens axis from the optical axis of the system. However, completely compensate for this all distortions of the projected image are impossible at once - computer correction is necessary)} ), which should also be attributed to the disadvantages of the device.

Significant disadvantages of the device include the fact that the rotation of the moving part of the optics (lens, mirrors, screen) relative to its fixed part (projector, transmitting optics) causes an undesirable rotation of the image in the plane of the screen (changing the orientation of the image). To eliminate this drawback, the use of special compensating optics with its own drive is required ^{(for example, the use of a “K” -shaped system of mirrors rotating twice as slow as the moving part of the optics and projection screen (see US patent No. 4943851))} or anticipatory rotation of the object’s cross sections before output, which causes additional loads of an already overloaded image preparation system and entails increased requirements for the synchronization of the parts of the display.

Summarizing, it can be argued that the implementation of the device requires the use of expensive complex and therefore not always reliable ^{(The DMD matrix used in the projector is not very reliable and durable (lasts 2-3 years)) of} service systems that are made to the limit of the capabilities of modern technology, but do not provide the full quality of the resulting three-dimensional image.

The disadvantages resulting from the non-optimal configuration of the optical display system according to US patent No. 6554430, partially eliminated in the known device (patent for utility model RU No. 91646, U1, CL G09G 3/00, H04N 3/00, publ. 02.20.2010 ), adopted in this description as the closest analogue to the proposed device.

According to the description, this three-dimensional display contains a rotating scattering screen and a projector mounted on one mounting base with a screen, which reproduces the dynamics of the raster images of a three-dimensional scene, moreover, the projector’s electronics are powered by an induction generator that generates electricity from the energy of mechanical rotation of the screen, and graphic information is transmitted the projector is carried out over the air (for example, using Bluetooth modules).

With such a simple configuration of the optical system, when the image source, the projection lens and the scattering screen are rigidly fixed on the same platform (mounting base), there is no need to tilt the screen relative to the plane of the primary image in the projector, i.e. there is no defocusing and different scale of parts of the image, which eliminates the need to correct images for passage.

The optical path length of the light beam from the projector matrix through the projection lens to the scattering screen does not change when the platform rotates, which avoids dynamic zooming. During skews and beats of the platform, the image does not shift relative to the scattering screen, which avoids image jitter for the observer.

Rotation of the screen and the projection lens of the device does not cause the image to rotate on the screen relative to the image on the projector matrix, which avoids the use of optical or computer image correction systems.

Thus, the optical system of this three-dimensional display for operation does not require mathematical processing and adjustment of data per pass, which makes it possible to use it not only for reproducing 3D computer objects, but also real scenes and objects. In this case, as components of the volumetric image of the object, it is possible to use not only the section of the object (or scene) with azimuthal planes, but the projection of the object on these azimuthal planes, i.e. footage of shooting a real scene in a circular fashion from different angles. The latter greatly simplifies the additional mathematical preparation of the object for demonstration and under certain conditions ^{(these conditions are described in the description below)} may make it unnecessary, which makes it possible to reproduce 3D images of real objects in real time. This important quality is absent in almost all known models of volumetric displays (or in their descriptions), which predetermined the choice of a prototype for the present invention.

Along with the undoubted advantages, this device has obvious disadvantages. These include insufficient information transfer speed. To transmit data in this device, the use of a radio channel, in particular Bluetooth modules, is proposed. National Radio Semiconductor’s Bluetooth RF modules (for example, LMX9820, as follows from the patent description) have a maximum data transfer rate of about 1 Mbps. The fastest known Bluetooth modules have a marginal performance of about 24 Mbps (when using Wi-Fi protocol). Moreover, at a rotation speed of the mounting base of 20-24 r / s per revolution of the screen, i.e. all sections of the object within 360 °) will have only 1 Mbps of transmitted information, which is several orders of magnitude less than in the Perspecta display, and significantly less than the calculated output speeds, i.e. this solution is also not able to provide high-quality reproduction of 3D objects and scenes.

Other disadvantages of this solution include the supply of the projector from an induction generator, which unnecessarily complicates the device, additionally loads the rotating mounting base and entails accelerated wear of the moving parts of the display.

A known method of forming three-dimensional images (US Patent No. 6302542 B1, class G03B 21/28, publ. October 16, 2001), including the sequential display of 2D frames on the image creation panel, the rapid rotation of the display plane (screen) around the first axis, rotation a multi-mirror reflector around a second axis at half the speed of the display rotation speed, projecting two-dimensional image frames first through projection path compensation means, then by reflecting them from the multi-mirrors onto the display. Compensation of the projection path in this case is carried out according to one of the following two variations - transmission of the image beam from the image panel through the lens, then its reflection from the reciprocating reflector system, which performs reciprocating motion in accordance with the angular position of the rotating multi-mirrors or projecting the image beam from image panels through scalable optics and the change in the optical power of this optics in accordance with the angular position of rotating multi-mirrors.

The second variant of the method includes displaying in a sequence of a set of 2D frames on the image creation panel, quickly rotating the display plane and thereby determining the display space, rotating the orthogonal system of switched reflectors at a speed equal to half the speed of the display, and projecting these two-dimensional image frames onto the display plane by reflecting them from said orthogonal system of switched reflectors. At the same time, the reflectors are switched between the transparent and reflective states in accordance with their angular position.

The disadvantages of this method, in the first place, are the sequential output of two-dimensional frames (which are either sections of the displayed object or its projection) to the image creation panel, which entails increased requirements for the speed of their display. As mentioned earlier, with the sequential output of two-dimensional frames on one projection device, the required performance of this device to create high-quality three-dimensional display of a three-dimensional object or scene is beyond the capabilities of modern technology. Attempts to speed up the output process of these frames by existing means lead to a decrease in either color or resolution of the output image, which inevitably entails a decrease in the quality of display of a three-dimensional object.

The disadvantages of this solution include the proposed method of projecting an image onto a screen ^{(“... display plane” in the wording of this patent, however, to avoid confusion with the subject of the invention, the word “screen” will be used when referring to a light-scattering body)} to ensure stable the orientation of two-dimensional projections (sections) relative to the screen, which involves the use of a multi-mirror reflector, or two switchable reflectors rotated at half speed in relative to the screen rotation speed. All this entails an unjustified complication of the optical system and the display drive and reduces the reliability of the device.

In the first version of the method, the use of a multi-mirror system required the introduction of means to compensate for changes in the projection path of the beam based on a reciprocating reflector system or scalable optics (each with its own drive), and in the second version, the introduction of a synchronous switching system for orthogonal reflectors. All this unnecessarily complicates the design of the display and leads to the appearance of additional distortions in the reproduction of two-dimensional slices of a three-dimensional image, reducing the quality of its reproduction.

In addition, the use of a multi-mirror reflector in the form of a polyhedron with an axis of rotation offset from the axis of rotation of the screen (Fig. 10 of US patent No. 6302542), when using one image panel (one image projector) does not provide a circular view of the displayed object ^{(In addition, as If you rotate the screen, a horizontal shift of the center of the image relative to the center of the screen will be observed)} In this case, the display will display the light model of the object only in the azimuthal angle, not exceeding 180 °.

In the second embodiment, the rotation of two orthogonal reflectors at half the speed of the screen speed and their simultaneous switching from the mirror state to transparent when using one image panel (projector) also does not provide a circular view of the observation object. Additionally, it should be noted that the reflection of light rays from the mirror, passing almost parallel to its surface, causes severe distortion of the reflected image caused by the imperfect surface of the mirrors. However, in the method under consideration, the reflecting mirror switches to transparency mode when its surface becomes parallel to the axis of the incident beam, i.e. immediately before the moment of switching the reflectors, the image projected onto the screen is subject to severe distortion. The latter cannot contribute to high-quality reproduction of the displayed object with this method of its formation.

Closest to the technical nature of the claimed solution, the method of forming three-dimensional images (patent US 6554430 B2, class G03B 21/28, G09G 5/10, publ. 04/29/2003), adopted in this description for the closest analogue of the proposed method.

The method includes rotating the projection optics and the projection screen around the axis of rotation, supplying a light beam from a stationary light source and projecting the light beam through the projection lens onto the projection screen, and adjusting the inclination of the projection lens so that its optical axis does not form an angle with the axis of rotation more than 10 degrees. The method further includes rotating the first and second mirrors around the axis of rotation, the projection optics may be a projection lens and this lens projects a light beam onto the first mirror, the first mirror directs the light beam to the second mirror, and the second mirror directs the light beam to the projection screen.

In embodiments, the method further includes rotating the third mirror about the axis of rotation, wherein the third mirror receives a light beam from the second mirror and directs the light beam to the projection screen, and the light beam from the light source to the projection lens is supplied using transmitting optics including a mirror, adjusting which center the beam of light on the projection screen.

As follows from the description, to compensate for trapezoidal distortions of the image in the plane of the screen, the display software first introduces distortion into it and performs adjustment of the orientation of the current section of the object. The latter is done to eliminate image rotation in the plane of the screen as the moving part of the display rotates.

The main disadvantages of this method of forming three-dimensional images include working only with computational models of demonstration objects and requires preliminary preparation of objects for display (for example, in the form of creating a three-dimensional computer model of an object). In the process of demonstration, the method assumes that there is serious processing of data per pass, which is confirmed by the need for operations such as calculating the current section of the object, introducing corrective distortion and adjusting the orientation of the current image in the plane of the screen. The need for these operations follows from the device of the optical display system ^{(see above)} and the sequence of actions for transmitting and forming three-dimensional images according to the formula and description of this method.

The need to use computing tools at all stages of the preparation and formation of three-dimensional images of computing tools at the limit of their performance limits the possibility of improving the quality of the resulting image and does not allow reproducing real objects and scenes in real time.

Other disadvantages of the method include the serial output of the current sections of the visualized object using only one projector, which imposes serious requirements on its performance, often increased by reducing image quality, which severely limits the possibility of using lower-speed, but more reliable analogues and reduces the reliability of the product in whole.

The above analysis of the prior art indicates that the above devices and methods, including such closest analogues as the device according to patent RU No. 91646 and the method according to US patent No. 6554430, do not provide the necessary reliability and durability of the three-dimensional display and limit the quality of the generated three-dimensional image. It is not possible to use this device and method for outputting real three-dimensional images and scenes in real time.

The problem to be solved in the present invention is the creation of a reliable and voluminous display with a circular view, capable of forming and visualizing with high quality in real time and with minimal use of computer technology three-dimensional images of objects and scenes, including real ones.

It follows from the foregoing that, to solve this problem, it is necessary to create both the display itself on the basis of a new, more optimal design of its optical system and more reliable and affordable projection tools, as well as a new method for generating and displaying images of projections (or sections) of a three-dimensional object that requires significantly less use of computing operations.

The technical result that can be obtained by implementing the claimed group of inventions is to provide the ability to play full-color volumetric objects or scenes that are visible without the use of individual means of stereo surveillance.

The problem is solved in that in the proposed three-dimensional display containing a scattering screen fixed in the center of the axis of rotation of the platform, a projector that reproduces raster images of a three-dimensional scene, which are transmitted to the screen through projection optics and a system of mirrors, according to a technical solution, the system of mirrors is placed coaxially with the platform and made in the form of a fixed axisymmetric mirror polyhedron, at the base of which is a regular polygon, and the outer surfaces are mirrored the side faces of the polyhedron, the projection optics is mounted on a rotating platform, and the projector is made in the form of a polyhedron similar to a mirror polyhedron, with the middle lines of the side faces of the projector parallel to the middle lines of the corresponding side faces of the mirror polyhedron and removed from the axis of rotation of the platform by a distance equal to twice the distance from the middle lines of the mirror polyhedron, and the inner surfaces of the side faces of the projector are configured to play raster on them images of a three-dimensional scene.

и $$f/e=\frac{C}{C+D}$$

(где "g" и "f" - части по горизонтали опорных образов "a" и "b" в составном изображении "e"), зависящими от относительного расстояния данного азимутального направления - "K" от границ диапазона - "A" и "B". Таким образом, оптическая система предлагаемого дисплея, состоящая из многогранного проектора, на гранях которого воспроизводятся опорные растровые образы, зеркального многогранника и вращающейся проекционной оптики, для каждого углового положения оптики создает свое составное изображение и по дискретным опорным изображениям равноплотно заполняет по кругу составными изображениями все азимутальные направления. Если в качестве опорных растровых образов выбрать сечения или проекции демонстрируемого объекта, взятые через равные угловые промежутки так, чтобы их количество по кругу равнялось количеству граней проектора, и воспроизвести их на этих гранях, то для любого азимутального положения подвижной части оптики будут существовать переходящие друг в друга изображения объекта, соответствующие текущему угловому положению проекционной оптики.The advantage of the proposed volumetric display is the property of its optical system to form composite images from two reference (Fig. 1) for an arbitrary azimuthal direction "K" lying inside the range whose boundaries are the directions to these reference raster images "A" and "B", reproduced on the inner surfaces of adjacent side faces of a polyhedral projector ^{(The azimuthal angle between two adjacent side faces of a polyhedral pyramid or prism is determined by the angle between the projections onto the base but and to these faces and can be found based on the number of sides of a regular polygon lying at the base of these figures)} . These composite images are a combination of two identically oriented and aligned centers of the reference raster images (for example, "a" and "b"), represented in the composite image by their relative shares $$g/e=\frac{D}{C+D}$$

and $$f/e=\frac{C}{C+D}$$

(where "g" and "f" are the horizontal parts of the reference images "a" and "b" in the composite image "e"), depending on the relative distance of a given azimuthal direction - "K" from the range boundaries - "A" and " B ". Thus, the optical system of the proposed display, consisting of a multifaceted projector, on the edges of which the reference raster images, a mirror polyhedron and rotating projection optics are reproduced, creates a composite image for each angular position of the optics and, using discrete reference images, fills all azimuthal images with equal density in a circle directions. If, as reference raster images, we select sections or projections of the demonstrated object taken at equal angular intervals so that their number in a circle is equal to the number of faces of the projector and reproduce them on these faces, then for any azimuthal position of the moving part of the optics there will be transitions into each other other images of the object corresponding to the current angular position of the projection optics.

The property of this display to combine support images with their centers can be illustrated by a diagram where a horizontal projection of the elements of its optical system is conventionally shown (Fig. 2). For an observer located along the "OK" axis, deviated by an arbitrary angle | α | <90 ° from the direction "OA" towards the center of the reference raster image (point "A"), reproduced on the side of the projector - the plane "P ₂ ", the image of this point ("A") reflected in a parallel plane mirror - "P ₁ " will be aligned with the center of rotation (point "O") if the distance between the planes "P ₂ " and "P ₁ " is equal to the distance from the point " O "to the edge of the mirror polyhedron" P ₁ ".

Through projection optics, the resulting image can be transmitted to a screen mounted on the same platform with this optics.

From the above description follows the requirements for the elements of the optical system of the proposed volumetric display. The external polyhedral projector should be similar and coaxial with the internal mirror polyhedron, with the center lines of the side faces of these two polyhedrons parallel to the base should be respectively parallel to each other, and the distance from the axis to the middle line of any side face of the projector should be equal to twice the distance of the corresponding face of the mirror polyhedron. This requirement is met by polyhedral prisms and truncated pyramids with regular polygons in the bases, as shown in FIGS. 3 and 4.

These properties of the optical display system can significantly reduce the use of computational operations to form intermediate images that fill the space between the reference raster images, because these images are formed by the optical display system and projected onto the screen by projection optics, and the technical means of image preparation and output can be used to create and output reference raster images of higher quality.

Let us evaluate the productivity necessary for the formation and output, for example, of 36 full-color raster images ^{(The number of supporting raster images necessary for the holistic perception of the object being demonstrated mainly depends on its properties (degree of symmetry, distance from the axis, required degree of detail, etc. ) and in most cases does not go beyond 12-36 reference images.If the operating conditions require significantly greater detail of the three-dimensional image or the display is supposed to be used as an exhibition full-time complex, then to increase the number of supporting raster images in this scheme, no serious technical limitations were identified.)} . The image of one frame with dimensions of 800 × 600 has 4.8 · 10 ⁵ pixels. Suppose that in one revolution of the screen 36 reference images are projected onto it, i.e. 17.28 · 10 ⁶ bills, then in a second the projector plays 432 · 10 ⁶ bills. When displaying a full-color image (i.e., with a 24-bit scheme), the required GPU performance will be 432 · 10 ⁶ × 24 = 10.386 · 10 ⁹ bit / s ≈ 10.4 Gb / s. This value is far from the maximum speeds of modern graphic processors, which provides a high probability of the development of the proposed system. It should also be noted that when working with ready-made projections of an object, the processor does not calculate them, but directly transfers them to the display output system.

An additional positive feature of the display is that both reference raster images and composite images do not change orientation when rotating projection optics and the screen. Because of this, and also because of the small changes in the lengths of the trajectories and projection angles, the projected image does not require preliminary mathematical processing and optical correction, which also contributes to the achievement of the claimed technical result.

This device does not require strict coordination of the rotation angles of the screen with the output of the current image, i.e. the processes of screen rotation and image output are essentially two practically independent processes, which simplifies the device and facilitates its management, while increasing the reliability of the proposed display and promoting a better display of three-dimensional images.

When demonstrating dynamic scenes, each of the image sources, which together comprise a multifaceted display projector, must update the image during one revolution of the platform, which corresponds to an output speed of about 25 frames / s. Such an output speed can be realized even by the lowest speed of the existing means of displaying information, which allows you to choose among them the most reliable and high-quality. A multifaceted projector can be composed, for example, of LCD panels from simple home appliances. Despite the low speeds, these screens have established themselves as reliable image output devices with long life, their own backlight and good color reproduction.

Thus, the claimed invention is fully consistent with the task of creating a reliable and durable surround display with high quality of the resulting three-dimensional image.

The quality of the three-dimensional image is also enhanced by the fact that the screen is lined with a retroreflective coating, the scattering angle of which in the azimuthal direction does not exceed 3 °.

As follows from the above, the volumetric display does not require serious mathematical processing of images per passage, which makes it possible to use real objects or scenes from the angles corresponding to the location of the faces of the multifaceted display projector as reference projections of video or photographing. In this case, isotropic diffuse scattering of the image on the screen will interfere with the perception of a three-dimensional object. At the same time, the projection of the object will be visible to the observer, corresponding to all azimuthal angles of rotation of the screen from 0 ° to 90 ° on both sides of the observation line.

To maintain the clarity of the resulting three-dimensional image, the screen can be lined with a coating (or equipped with a nozzle with a coating) having anisotropic scattering in the azimuthal direction, which sharply narrows the visibility zones of the projected image. Only the images remain visible to the observer at screen positions practically perpendicular to the direction of observation. It has been established that the best in clarity results are obtained when applying coatings with a viewing angle in the azimuthal direction not exceeding 3 ° from the perpendicular to the screen surface. Of the existing coatings, the most common properties required are those of widespread retroreflective coatings.

Azimuthal anisotropy does not prevent the observer from seeing the displayed object or scene in volume, as according to the foregoing, the observer's right and left eyes receive slightly different images of the object, which the brain interprets as a stereoscopic pair. Given that such a pseudo stereopair exists for any azimuthal position of the observer relative to the display, it can be argued that the observer will see the correct volumetric image corresponding to the relative position of the observer and the object of the demonstration.

This version of the volumetric display allows you to observe three-dimensional images of real-life objects, including dynamic, which improves the quality of the generated image, bringing it closer to real, and significantly expands the applicability of the proposed display. Since when using photo and video projections of a demonstration object, a relatively labor-intensive mathematical processing of images per passage is not required, this display option can be used to show real-life objects and scenes in real time, including and for broadcasting to a mass extraterritorial audience.

The achievement of the specified technical result is facilitated by the fact that projection optics consists of a mirror and a lens, and the mirror is installed with the ability to receive raster images from the stationary mirrors of the polyhedron and direct them into the lens, which is placed so that it is able to project raster images on the screen (Fig. 5 )

A variant of the implementation of a volumetric display is possible, in which the projection optics consists of a lens and a mirror, and the lens is mounted so that it has the ability to receive raster images from the stationary mirrors of the polyhedron and direct them to the mirror, and the mirror is placed with the ability to direct raster images to the screen (Fig. .6).

The achievement of the claimed result is also facilitated by the embodiment of the display, in which the projection optics is additionally equipped with a second lens and a second mirror placed opposite, and the screen is double-sided.

This design allows the observer to see a three-dimensional image when passing through the line of observation of two sides of the screen, which doubles the brightness of the observed three-dimensional image with the same aperture of the projected images. This corresponds to the task of improving the quality of the resulting image.

Improving the image quality, reliability and durability of the volumetric display is facilitated by such an option in which projection optics consists of a lens, and the fixed mirror system is supplemented by a coaxial platform and a mirror cylinder covering a mirror polyhedron with a reflecting inner side surface (Fig. 7).

The advantage of this modification of the display is that a mirror is excluded from the moving part of the projection optics, which reduces the load on the drive of the rotating part of the device and, due to the static nature of the reflecting mirror cylinder, reduces the jitter of the resulting image due to distortions and vibration of the rotating parts of the display (Fig. 8).

All this helps to increase the reliability of the surround display and improve the quality of the resulting image. The distortions introduced into the projected image by the cylindricality of the mirror are offset by the introduction of a corrective lens into the lens.

Variants of the implementation of the volumetric display are possible, in one of which the mirror cylinder is installed with the ability to receive raster images from the mirror polyhedron and direct them to the lens, which is able to project raster images on the screen, and in the other the mirror cylinder is installed with the ability to receive raster images from the lens and direct them to the screen, and the lens has the ability to receive raster images from a mirror polyhedron.

Such a configuration of the display optical system, as well as its modifications described above, has the property of maintaining the image orientation in the plane of the screen unchanged during screen rotation and projection optics. When using simple projection optics ^{(which does not include a system of image transfer lenses)} , this orientation may not coincide with the orientation of the original image, however, it remains unchanged when the optics and the screen rotate, and the orientation mismatch can be taken into account when arranging a multifaceted projector from elements that are image sources (Fig.9).

To improve the quality of the obtained three-dimensional image, the projection optics in these variants of the three-dimensional display can be additionally equipped with an oppositely located second lens, and the screen can be made double-sided (Fig. 10).

Thus, the application of the proposed volumetric display provides a solution to the problem and the achievement of the claimed technical result for all of the above areas of its use.

In the proposed volumetric display in all its variants with additions, the method of forming three-dimensional images is used, including rotation of the projection optics and a scattering screen around the axis of rotation of the platform, projecting raster images of a three-dimensional scene from the projector through a system of mirrors and projection optics onto the screen. In this case, raster images are first formed on the inner side of each of the side faces of the projector, made in the form of a polyhedron, coaxial and similar to a fixed axisymmetric polyhedron of the mirror system, at the base of which there is a regular polygon, then the raster images reflect from the outer side faces of the mirror polyhedron, then project them to the screen through rotating projection optics.

In contrast to the above, this method is characterized by increased speed, less use of high-speed computing and projection equipment, improved image quality and reliability. These properties are provided due to the fact that:

- the proposed method uses one of the fastest methods for the formation of intermediate images - combining light fluxes from the reference images, and the reference images during the display can change at times when they (or composite images obtained using them) are not projected onto the screen. The latter provides the ability to increase the speed of rotation of the screen ^{(This speed is limited only by the speed of updating the image on the output devices, and it, for example, for household LCD panels can be on the order of 0.01 seconds)} compared with the methods discussed above and / or the ability to project on both sides of the screen , which improves the quality of the resulting three-dimensional image;

- in this method, all intermediate images are formed independently according to the few reference raster images of the demonstration object and without additional mathematical processing, which makes it possible to use higher-quality output devices, and the released computing power to improve the quality of the resulting image;

- the method provides the ability to use existing and widespread output devices and image formation, which improves the reliability and performance of the product as a whole;

- this method of forming and projecting images does not require serious correction of the projected image onto the passage, and the formation of a three-dimensional image from its projections does not require calculation of any angles, so it becomes possible to demonstrate full-color photo and video filming of a real object or subject and the possibility of broadcasting in real time.

In one embodiment of the proposed method, projection optics, consisting of a lens and a mirror, are located so that the raster images reflected from the mirror polyhedron are first projected through the lens onto a mirror and then sent to a scattering screen.

In another embodiment, projection optics, consisting of a mirror and a lens, are located so that the raster images reflected from the mirror polyhedron are first directed to the mirror, then reflected into the lens and projected through it onto a diffusing screen.

To reduce the jitter of the resulting three-dimensional image due to distortions and vibrations of the moving parts of the display, such a modification of the proposed method is possible in which the projection optics consist of a lens and the stationary mirror system is supplemented by a cylindrical mirror covering a mirror polyhedron with a reflecting inner side surface located coaxially to the platform so that the raster the images reflected from the mirror polyhedron are projected onto the scattering screen through the lens and a cylindrical mirror.

Summarizing, it can be argued that the proposed method with its modifications is fully consistent with the task set in this invention.

The device and method according to the present group of inventions are illustrated by the example of a preferred embodiment with reference to the accompanying drawings, in which Fig. 1 is a diagram explaining the formation of composite images from two reference ones; figure 2 presents a diagram explaining the principle of combining the reference images of their centers in the optical display system; figure 3 and 4 show options for spatial figures that satisfy the requirements for the elements of the optical display system; 5 and 6 are layout diagrams of a surround display with a movable mirror; figure 7 shows an example of the layout of the volumetric display with a fixed cylindrical mirror; Fig. 8 illustrates the effect of image stability when the platform is shifted and skewed; Fig.9 explains the features of the orientation of the images in the plane of the screen; figure 10 shows an example layout of a volumetric display with a double-sided screen.

The volumetric display (Fig. 5 and Fig. 6) includes a scattering screen 1 fixed in the center of the rotation axis 2 on the platform 3, a multifaceted projector 4, projection optics 5 and a mirror polyhedron 6. Projection optics 5 in this embodiment of the display consists of a mirror 7 and a lens 8 mounted on a platform 3 and rotating together with it and a scattering screen 1 around a common axis 2. The difference between one modification (Fig. 5) and the other lies in (Fig. 6) only in the sequence of arrangement of the lens 8 and mirror 7.

In one embodiment of the volumetric display, the scattering screen 1 may be coated with a retroreflective coating. To increase the brightness of the obtained three-dimensional image, the projection display optics can be located on both sides of the scattering screen 1, while the scattering screen 1 is double-sided, and in the case of using a retroreflective coating, the lining is also made on both sides of the scattering screen 1.

The embodiment of the volumetric display (Fig. 7) includes all of the parts listed above except that the projection optics consists only of lens 8, and the optical system of the display is supplemented by a coaxial platform 3 covering a mirror polyhedron 6 with a mirror cylinder 9 with a reflective surface on its inner side.

In the embodiment of this modification of the volumetric display (Fig. 10), in addition to the lens 8, a similar lens 10 is used, mounted on the platform 3 diametrically opposite to the lens 8. In this case, the scattering screen 1 of the volumetric display is double-sided.

The above layout diagrams of the proposed volumetric display depict only those main nodes, without the details of which it is impossible to illustrate the operation of this device and the implementation of the method of forming three-dimensional images. Minor components and details of the display, especially those to which special requirements are not imposed in the framework of this description, are deliberately omitted so as not to clutter the drawings. This does not mean that they are not required at all for the operation of the proposed display, but only indicates that for the successful operation of the proposed device, the parameters of these nodes can be selected from a wide range without compromising the performance of the display. Such nodes, for example, include a drive system for rotating the display platform, light sources, etc. ^{(There are relatively many such assemblies and parts, these include controllers for matching the inputs of the display, numerous transmission devices, cases, housings, and much more, which is not directly related to the subject of the invention and performs a regular function in the display)} . In addition to the parameters indicated above, specific requirements are not imposed on these nodes. In particular, the drive system is only required to ensure the rotation of the platform and the nodes attached to it with a frequency of the order of 25 r / sec, due to the condition of “continuous” image perception. Other characteristics of the drive, such as increased stability, synchronization with the output of the current image, etc., for the successful functioning of the proposed surround display are desirable, but not required. A similar statement is true for a lighting system (backlight) of images displayed on the inner sides of the side faces of a multifaceted projector. A priori, it is assumed that such a system exists and that it is sufficient to distinguish the images on the display screen. However, in addition to this, specific requirements caused by the essence of the invention to the proposed system are not presented. Moreover, depending on the image output means used, the lighting system may change, remaining within the standard functions for projection technology, i.e. these systems are not related to the subject of the invention and are not at the inventive level, but can be arranged using well-known circuits of known components and parts. When describing an example embodiment of the proposed display, some specific implementations of nodes of this type will be proposed, however, this is not directly related to the subject of the invention. Therefore, the following description implies that these devices are available, and their use is reduced to the performance of standard functions and does not affect the essence of the invention.

The operation of the proposed device, as well as the implementation of the claimed method of forming three-dimensional images, we consider the example of a three-dimensional display in the version with a stationary cylindrical mirror (Fig.7).

Pre-recorded or obtained during the demonstration shots of the displayed subject from 12 angles (for example, from 12 cameras) are displayed on the side faces of the inside of the multi-faceted projector 4. For different implementations of the display, these faces can be composed of LCD panels with their own or external illumination or LCOS - panels working on reflection. When using the device for demonstrating only static images (volume slides), photographs of the object from the required angles printed on a specific medium (for example, film or photographic paper) and held in the correct position (i.e., along the edges of a multifaceted one) can be used as reference image sources. projector 4) with special guides or transparent clips.

Such image sources, depending on the properties of their media, can operate in reflected or transmitted light received from a display lighting system.

During the operation of the display, the platform 3, the screen 1 and the lens 8 (and a similar lens 10) of the projection optics 5 mounted on it rotate about an axis 2, which is the center of rotational symmetry of the display. If the plane of the screen 1 occupies a perpendicular azimuth to one of the supporting raster images (for example, as in Fig. 7), this raster image will be completely reflected in the opposite face of the mirror polyhedron 6, then, passing through the focusing lens 8 and reflected from the cylindrical mirror 9 ^{( To correct the distortions introduced into the projected image by a cylindrical mirror, a cylindrical lens can be included in the lens)} , will be projected onto screen 1 (the ray path in Fig. 7 is shown by thin lines).

When you rotate from this position of the platform 3 to a certain angle (for a twelve-sided projector by an angle α <30 °), the reference field of the lens 8 will contain reference raster images that are currently on adjacent faces of the polyhedral projector 4. These raster images represent frames shooting a demonstrated object from angles unfolded one relative to another at an angle of 30 °. Based on the selected configurations and the relative position of the projector 4 and the mirror polyhedron 6, these raster images will be aligned in the plane of the screen 1 with their centers (see the diagram in figure 2). Parts of these reference images reflected from adjacent faces of the mirror polyhedron 6 (Fig. 7) pass through the lens 8 and are projected onto the screen 1 as a composite image ^{(A similar principle of the formation of one image from two, but for the purpose of the nascent animation was used in praxinoscope. (English praxinoscope) - an optical device patented by Emile Reynaud (Fr. Emile Reynaud) August 30, 1877 (Wikipedia))} . The shares of the reference images are mainly proportional to the angular displacement of the lens 8 with respect to the azimuthal directions on the adjacent faces of the projector 4 (see the diagram in Fig. 1), and the images are docked along the vertical border (or along the border passing at a small angle to the vertical ^{(B depending on which figures (prisms or truncated pyramids) are used as shaping bodies of the optical display system)} ). The width of the alignment zone of two adjacent reference images on the screen 1 depends on the degree of roundness of the junction of two adjacent reflective planes of the mirror polyhedron 6. When the lens 8 is moved from one of these raster images to the other, the first image is gradually replaced by the second one, much like the image on the monitor screen is replaced computer, only horizontally, i.e. Each current azimuthal position of the lens 8 corresponds to its own image on the screen 1, which is slightly different from the previous one. The formed image, reflected from the mirror 9, is projected onto the screen 1, which moves together with the platform 3 and the lens 8 and at each moment of time is perpendicular to the azimuthal position of the lens 8. To correct distortions from the mirror 9, a cylindrical lens is introduced into the lens 8 ^{(When using a flat movable mirror 7 (Fig. 5 or 6) there is no need for such additional correction)} , a slightly stretching image horizontally.

The display variant with a fixed cylindrical mirror (Fig. 7) also has high stability of the resulting volume image to displacements (Fig. 8a) and distortions (Fig. 8b) that may occur during rotation of the platform 3. With significant axial and vertical displacements S ₁ platform 3 (in the diagram of Fig. 8a, the displaced position of the platform is indicated as 3a) from its original starting position (lighter lines in the diagram) due to the stationarity of the elements of the optical display system — projector 4, mirror polyhedron 6 and cylindrical a mirror 9 beam path to lens 8a is not changed. The plane-parallel displacement of the lens 8a relative to its original starting position 8 (shown lighter) practically does not make any changes in the course of the rays (dashed line) to the screen 1a compared to their original path (shown by bright lines). Thus, for the observer, the offset of the final image S ₂ remains substantially less than the platform offset S ₁ .

Similar reasoning can be given for the case of skew σ ₁ (Fig.8b) platform 3b relative to the initial position 3, because in the paraxial approximation, the image of the subject is insensitive to a slight displacement and deviation of the axis of the projecting lens. It is much more dependent on the position of the subject itself. As shown above, the position of the subject remains static for this case, which contributes to the static nature of the resulting volumetric image.

When using a simple projection lens 8, the image in it is flipped from top to bottom and from right to left ^{(In fact, it also flips when reflected in mirrors, but when using an even number of reflections, these flips are mutually compensated)} (see the diagram in Fig. 9). In order for the observer to see the correct image on screen 1, this fact must be taken into account when arranging the multi-faceted projector 4 from elementary image sources, i.e. either feed the reference images appropriately inverted (based on reading the images in the opposite direction), or inverted to mount elementary image sources on the faces of the multi-faceted projector 6.

This can be avoided if two transfer lenses are introduced into the lens 8 (Fig. 7), one of which creates an inverted image in the space between them (in the intermediate focal plane), and the second returns it to its original position.

For the correct perception of three-dimensional images in the case when photo or video images are used as reference images, it is desirable to cover the surface of the screen 1 with a material reflecting (scattering) light in a narrow azimuthal direction. For this, you can use retroreflective coatings (films), produced in a wide variety, including and with a greater degree of scattering anisotropy ^{(See, for example, http://www.orafol.com.)} than is necessary for this task. An important property of such coatings for this application is the high efficiency of the use of reflected light. With the right choice of coating parameters in the direction of observation, almost the entire luminous flux received from the source leaves, which can significantly increase the brightness of the observed image.

The ratio of the light flux leaving in a given direction to the incident one is described by the directional scattering coefficient. The angular distribution of this coefficient is characterized by the scattering indicatrix of the coating. For use in the proposed volumetric display, it is desirable that the vertical indicatrix of the coating has a flat offset maximum, and the horizontal — an angular width of the order of 3 ° and a maximum that matches the direction to the light source. Such a characteristic can be obtained on coatings using refractive glass microfibers (microfilaments) oriented along the vertical axis of the screen.

The adjacent reference images used in the display were obtained from fairly close directions to the object of the demonstration, and the differences between them become smaller the larger the number of them used to form a three-dimensional image. The border between such images in a mixed image is almost invisible, especially if the displayed image is moving.

Given that the horizontal indicatrix of any retroreflective coating has a finite width, i.e. if there is a non-zero viewing angle of images on the screen with such a coating, then the observer will see simultaneously several images (close) to each other (packet) corresponding to these viewing angles. The boundaries in the images of the package go a little differently, so the superposition of these images additionally helps smooth the transition between parts of the mixed image. However, if the coverage indicatrix is chosen too wide, the observer will see a fuzzy image of the object. For the proposed display, the optimum angle of dispersion of the coating is an angle not exceeding 3 °.

Due to the fact that the right and left eyes of the observer have slightly different azimuthal angles in the coordinate system of the display (at a distance of 1.2 m, the angular difference in the position of the eyes is approximately 3 °), the total images obtained by the eyes of the observer will also be slightly different. Subject to the correct sequence of placing the reference images on the edges of the projector 6, the left eye of the observer will receive images of the object a little on the left side, and the right one, respectively, on the right. These two images constituting a pseudostereopair are interpreted by the brain as a three-dimensional image of an object. Any azimuthal position of the observer around the display corresponds to its own stereo pair, i.e. moving in a circle, the observer without the use of special means of observation will see a three-dimensional object from the corresponding side. As the observer approaches the display, the difference in the azimuthal positions of his eyes in the coordinate system of the display will increase, therefore, he will see images with large differences or a stereo pair with large parallax, which corresponds to the approximation of the observer to a real object. Thus, when moving relative to the image formed by the proposed volumetric display, the observer will experience sensations similar to those when moving relative to a real object.

Thus, the proposed three-dimensional display and the method of forming three-dimensional images used in it can reproduce a three-dimensional image of the object being demonstrated, visible round-the-clock without the use of individual means, without imposing significant restrictions on the color and quality of the resulting image. When using photo and video frames as reference images, the application of the proposed group of inventions allows not to subject the image to serious mathematical processing for the passage. If, simultaneously with the demonstration of a real scene or object (subject), the current reference images are broadcast (or along dedicated lines), then there are practically no restrictions for organizing broadcasts of such scenes to a wide extraterritorial audience.

Based on the foregoing, we can conclude that the invention provides a solution to the problem described in the description and the achievement of the claimed technical result.

The proposed volumetric display can be used for:

- Demonstration of volumetric full-color dynamic real and virtual objects for a mass un-equipped audience at exhibitions and biennials;

- the organization of broadcasts of public performances and shows in the format of pseudo-topographic images for extraterritorial groups of viewers in real time, as well as in recording playback mode;

- volumetric visualization of the situation in a controlled air or underwater space in real time;

- organization of presentations in 3D “augmented reality” and 3D “augmented virtuality” formats for a mass un-equipped audience;

- development and demonstration of design and architectural solutions based on three-dimensional autostereoscopic displays with a circular overview of individual and studio use;

- medical applications (surgery, diagnostics, magnetic resonance or X-ray tomography) in the form of circular three-dimensional displays with the function of controlling the image of the object;

- schools and other educational institutions in the form of a cheap slide projector with a 360 ° view as a large virtual visual aids;

- home collections of voluminous circular photographs, virtual sculptures and architectural ensembles, images of real and fantastic equipment, iconic and art objects.

Of these, the simplest in composition is a volumetric slide projector, which can be used as an inexpensive visual aid in educational institutions and as "photo frames" for volumetric photographs at home.

The image source for the multi-faceted projector 4 (Fig. 5) in the display can be, for example, a color slide film with a longitudinal arrangement of frames (36 frames 24 × 36 mm in size, gaps - 2 mm, image pitch - 38 mm). The reference images of the displayed object are shot in a circle every 10 degrees, the film appears according to the E-6 procedure. From the base of the slide projector, the finished film is inserted into the slotted circular cassette with a diameter of 436 mm so that the centers of the frames coincide with the centers of the mirror faces of the polyhedron 6. The distance from the center to the middle of the mirror face of the polyhedron 6 should be 109 mm. As a mirror polyhedron 6, a hollow aluminum prism with 36 polished faces is used, which is mounted on racks to a fixed display base.

Inside the cavity of the mirror polyhedron 6 are the nodes of the display lighting system and the drive mechanism of the platform (not shown in the diagram). The rotating platform 3 is used to mount a movable mirror 7, a lighting mirror, a lens 8 (for example, OP-451 or OP-452), a screen 1 and an aerodynamic casing (not shown). Platform 3 is made of light opaque material (for example, duralumin). The platform is equipped with an axis with two support rolling bearings mounted inside the cavity of the polyhedron 6. A pulley is connected to the platform axis, connected by a belt drive (1: 2) to a drive motor pulley (not shown). A drive motor (for example, ДАК86-40-1.5 IM3681 or ДА086-18-1,5-Д48) is placed inside the cavity of the mirror polyhedron 6 and is attached to its upper end, on which the upper bearing of the platform 3 axis is also fixed. The axis of the platform with its lower end passes through the lower support bearing, and its protruding part serves to mount the movable nodes of the display lighting system.

The lighting system of the display consists of a fixed lighting lamp and movable units - a reflective casing, a condenser lens and a lighting mirror. A lighting lamp (e.g. OSRAM POWERSTAR HQI-T 150 / D) is mounted in the center of the display base. The lighting mirror is mounted on the platform 3 directly under the movable mirror 7 of the projection optics 5 so that the light beam formed by the reflective casing and the condenser lens hits the lighting mirror and then passes through the reference images on the film of the multifaceted projector 4. Reflective casing (spherical reflector) and a condenser lens (for example, a Fresnel lens) are fixed on the protruding part of the axis of the platform 3 so that the light beam formed by them is directed towards the illumination rkala. The platform, together with the fixed nodes, undergoes dynamic balancing.

A transparent aerodynamic casing (polyacryl) in the form of a hollow truncated cone is fixed on the platform. The lower base of the casing in several places around the perimeter is attached to the platform so that the casing can be removed to reconfigure the display. A diffusing screen 1 is inserted into this casing, which can be equipped with a special insert for displaying photo images. The screen is made of sheet material (for example, fiberglass), glued with a light-reinforcing film (for example, Scotchcal 3635-100) and equipped with an insert lined with a retroreflective coating (for example, Avery Dennison T-5500 film). In another embodiment, the screen 1 can be made in two interchangeable versions with scattering and retroreflective coatings. The display is closed by a protective removable housing (not shown), the upper part of which is made of a transparent material (polyacryl). The housing is attached to the base of the display.

The operation of the slide projector does not differ fundamentally from the operation of the display described above, except that the slide projector can show only static three-dimensional images. To quickly change these images in the slide projector can be provided with a mechanism for rewinding the film 36 frames forward. To demonstrate the object from all sides, you can provide a mechanism for slow rotation of the display around its axis. The motion drive can be carried out from the drive motor of the slide projector.

The given implementation example shows the promise of using the claimed device and method for the listed applications. An example allows you to clearly illustrate the fact that for the formation and display of three-dimensional images in some modifications of the proposed display there is no need to use computing power and high-speed output devices. In other versions of the display, these powers are significantly released, which improves image quality and reliability of the display. This is the technical result achieved by the application of the invention.

The above embodiments are set forth for the sole purpose of illustrating the proposed group of inventions. It will be appreciated by those skilled in the art that various modifications, additions and substitutions are possible without departing from the scope and meaning of the present group of inventions disclosed in the attached claims.

INFORMATION SOURCES

1. Pat. 2164702 Russian Federation, IPC ⁷ G02B 27/26. Device for demonstrating stereoscopic images. / Nikonov A.V., Dolgov V.M., Dolgov Yu.M., Nikonov A.A. (all RU); Applicant and patent holder Saratov State Technical University - No. 99106816/28; declared 04/05/99; publ. 03/27/01.

2. Pat. 2260829 Russian Federation, IPC ⁷ G02B 27/26. Device for demonstrating stereoscopic images. / Nikonov A.V., Dolgov V.M., Dolgov Yu.M. (all RU); Applicant and patent holder Saratov State Technical University - No. 20022112530/28; declared 05/13/02; publ. 02/10/04.

3. Pat. 24747467 Russian Federation, IPC ⁷ G02B 27/22. Autostereoscopic display / Chestak Sergey (KR), Kim Dae-Sik (KR); Applicant and patent holder Samsung Electronics Co., Ltd. -2009113551 / 28; declared 10/10/07; publ. 04/10/12, Bull. No. 10.

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Claims (13)

1. A three-dimensional display comprising a scattering screen, mounted on the center axis of rotation of the platform, a projector that reproduces raster images of a three-dimensional scene, which are transmitted to the screen through projection optics and a system of mirrors, characterized in that the system of mirrors is placed coaxially with the platform and is made in the form of a fixed axisymmetric a mirror polyhedron, at the base of which there is a regular polygon, and the outer surfaces of the side faces of the polyhedron are mirrored, projection optics are fixed on a rotating platform, and the projector is made in the form of a polyhedron similar to a mirror polyhedron, with the middle lines of the side faces of the projector parallel to the middle lines of the corresponding side faces of the mirror polyhedron and removed from the axis of rotation of the platform by a distance equal to twice the distance from it of the middle lines of the mirror polyhedron, and the inner surfaces of the side faces of the projector are configured to reproduce raster images of a three-dimensional scene on them. 2. The volume display according to claim 1, characterized in that the scattering screen is lined with a retroreflective coating, the scattering angle of which in the azimuth direction does not exceed 3 °. 3. The volumetric display according to claim 1, characterized in that the projection optics consists of a mirror and a lens, and the mirror is installed with the ability to receive raster images from the stationary mirrors of the polyhedron and direct them into the lens, which is placed so that it is able to project raster images on screen. 4. The volume display according to claim 1, characterized in that the projection optics consists of a lens and a mirror, and the lens is mounted so that it has the ability to receive raster images from the stationary mirrors of the polyhedron and direct them to the mirror, and the mirror is placed with the ability to direct raster images on the screen. 5. The volumetric display according to claim 1, characterized in that the projection optics consists of a lens, and the fixed mirror system is supplemented by a coaxial platform and a mirror cylinder covering a mirror polyhedron with a reflecting inner side surface. 6. The volumetric display according to claim 3 or 4, characterized in that the projection optics is additionally equipped with a second lens and a second mirror placed opposite, and the screen is double-sided. 7. The volume display according to claim 5, characterized in that the mirror cylinder is mounted with the ability to receive raster images from the mirror polyhedron and direct them into the lens, which has the ability to project raster images on the screen. 8. The volume display according to claim 5, characterized in that the mirror cylinder is mounted with the ability to receive raster images from the lens and direct them to the screen, and the lens has the ability to receive raster images from the mirror polyhedron. 9. The volumetric display according to claim 7 or 8, characterized in that the projection optics is additionally equipped with an oppositely located second lens, and the screen is double-sided. 10. A method for generating three-dimensional images, including rotating projection optics and a scattering screen around the axis of rotation of the platform, projecting raster images of a three-dimensional scene from the projector through a system of mirrors and projection optics onto the screen, characterized in that the raster images are first formed on the inner side of each of the side faces a projector made in the form of a polyhedron coaxial and similar to a fixed axisymmetric polyhedron of a system of mirrors, at the base of which there is a regular poly olnik, raster images are then reflected from the external side faces of the polyhedron mirror then projecting them on a screen through projection optics rotating. 11. The method according to claim 10, characterized in that the projection optics, consisting of a lens and a mirror, are located so that the raster images reflected from the mirror polyhedron are first projected through the lens onto a mirror and then sent to a scattering screen. 12. The method according to claim 10, characterized in that the projection optics, consisting of a mirror and a lens, are located so that the raster images reflected from the mirror polyhedron are first directed to the mirror, then reflected into the lens and projected through it onto a diffusing screen. 13. The method according to claim 10, characterized in that the projection optics consists of a lens, and the fixed mirror system is supplemented by a cylindrical mirror covering a mirror polyhedron with a reflecting inner side surface located coaxially to the platform so that raster images reflected from the mirror polyhedron are projected onto scattering screen through the lens and a cylindrical mirror.

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