Abstract: Disclosed is a laser scan type projector including laser light sources for three colors which alternately emits a laser light relating to an image for left eye and a laser light relating to an image for right eye on the basis of an image signal, a polarization switching unit which makes the laser light relating to the image for left eye and the laser light relating to the image for right eye, a first ¼ wavelength phase difference device which makes the two laser lights in which the polarization directions are switched by the polarization switching unit enter and which converts the polarization directions of the entered two laser lights so that each of the two laser lights be a circularly polarized light in an opposite direction from each other and a scan unit which scans a projection screen with the laser lights which are circularly polarized.

Abstract: Liquid crystal spectacles are provided for three-dimensional viewing of digital video content from a projector. The viewing spectacles include a first rectilinear polariser and a second rectilinear polariser respectively having polarisation axes P1 and P2, the polarisation axes P1 and P2 being parallel or perpendicular relative to each other. Furthermore, the liquid crystal has an adapted intrinsic tilt angle and is used in a half-wave blade configuration. The liquid crystal further includes first and second separate areas, each respectively located opposite a vision axis. The first area includes a first director and the second area includes a second director. The first and second directors are oriented so as to define an adapted angle between them. This enables a “non-one-eyed” vision while waiting for the projection of the film to start, and to obtain the best possible contrast between the two eyes of the user when viewing the digital video content.

Abstract: A system is provided for projecting a three-dimensional image. The system includes a light source and a polarization conversion system for converting light emitted from the light source to circular polarization. A beam splitter device is disposed adjacent the light source to receive light, and an LCoS image device is disposed adjacent the beam splitter device.

Abstract: A projector system that includes a first input device, a second input device, a control device, a sensor and a phase locked loop (PLL). A phase reference signal is created based on a signal rate of the first input device. A phase feedback signal is created based on the rotational speed of the second input device as it is measured by the sensor. The PLL compares the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized. A signal is sent to the control device for the second input device to change the rotational speed of the second input device in response to determining that the first input device and the second input device are not synchronized.

Abstract: A method for projecting a three-dimensional image, that includes providing a first light source and a second light source. A polarizing beam splitter (PBS) is disposed adjacent the first light source and the second light source. An imaging device is adjacent the PBS. A polarization flipping element is disposed adjacent the PBS opposite the imaging device, and a mirror is disposed adjacent the polarization flipping element. A first light is emitted from the first light source. The first light is polarized such that it reflects through the PBS to a polarization flipping element. The first light passes through the polarization flipping element twice such that it will reach the surface of the imaging device. The second light is emitted from the second light source after the first light is emitted. The second light is polarized such that the light passes through the PBS to the imaging device.

Abstract: A method is provided that includes providing a light source having a light emitting diode (LED) that emits a light. A polarization conversion system (PCS) is located adjacent the LED and has both a linear polarizer and a wave plate. A polarizing beam splitter (PBS) is adjacent the light source and an imaging device is adjacent the PBS. The wave plate of the PCS is rotated to a first position, and a first light is emitted by the LED in the first light source. This first light is converted to circular polarization. This first light travels to the PBS where it is reflected onto the imaging device. The wave plate is then rotated to a second position, and a second light is emitted by the light source. This second light is converted to circular polarization and reflects from the PBS onto the imaging device.

Abstract: A system provided for projecting a three-dimensional image. The system includes a first light source, emitting a light of a first color and a second light source emitting light of a second color. At least one polarizing beam splitter (PBS) is disposed adjacent the first light and the second light source, and at least one imaging device is disposed adjacent the at least one PBS.

Abstract: A system is provided for projecting a three-dimensional image. The system includes a first light source, the first light source emitting light in a first direction and a second light source emitting light in a second direction. A beam splitter device is disposed adjacent each light source and an imaging device is disposed adjacent the beam splitter device. Light from the first light source and the second light source travel a common optical path to a projector lens assembly.

Abstract: Optical systems, such as 2-D and 3-D projection systems, may be configured to have a compact back focal length to allow for more compact projection lenses, lower throw ratios, improved contrast, or any combination thereof. In an embodiment, an optical system may include a relay element configured to form an intermediate image having a focal point proximate to a projection lens.

Abstract: A method and system are described for projecting stereoscopic images using circularly polarized light with at least one polarizer for limiting the amount of light or radiant energy reaching a projection lens system and associated optical elements, and system configurations are discussed with respect to desired performance characteristics.

Abstract: Multiple image projection apparatus are described. A cubic multi-prism beam splitter is provided having diagonal interfaces with one or more PBS elements and/or reflective elements positioned thereon. At least first and second spatial light modulators, such as LCoS SLMs, are positioned adjacent the beam splitter cube. The first and second LCoS spatial light modulators and first and second projection optics systems are configured to output a first modulated image from the first LCoS SLM to the first projection optics system and a second modulated image from the second LCoS spatial light modulator to the second projection optics system. In other embodiments, additional LCoS spatial light modulators and light sources produce 3-D images. Addition of sensors permits user interaction with a projected image which is fed back to a controller to optionally change current or future images displayed by the system.

Abstract: A polarization conversion system (PCS) is located in the output light path of a projector. The PCS may include a polarizing beam splitter, a polarization rotating element, a reflecting element, and a polarization switch. Typically, a projector outputs randomly-polarized light. This light is input to the PCS, in which the PCS separates p-polarized light and s-polarized light at the polarizing beam splitter. P-polarized light is directed toward the polarization switch on a first path. The s-polarized light is passed on a second path through the polarization rotating element (e.g., a half-wave plate), thereby transforming it to p-polarized light. A reflecting element directs the transformed polarized light (now p-polarized) along the second path toward the polarization switch. The first and second light paths are ultimately directed toward a projection screen to collectively form a brighter screen image in cinematic applications utilizing polarized light for three-dimensional viewing.

Abstract: A projection autostereoscopic display including an image projector and a stereo screen is provided. The image projector projects an image. The image includes multiple viewing-zone images. The stereo screen receives the image and reflects the image to an observing direction. The stereo screen includes a linear polarizer layer, for receiving and polarizing the image. A first microretarder layer is disposed behind the linear polarizer layer. A second microretarder layer is disposed behind the first microretarder layer by a distance. A reflection-type polarization-reserved diffuser layer is disposed behind the second microretarder layer for reflecting and diffusing the image into various directions while maintaining the polarization state of the image. A switching layer is switched between a transparent state which maintains the polarization state of the image and an opaque state which changes the polarization states of the image to a non-polarization state, to switch between 2D and 3D display modes.

Abstract: A stereoscopic display apparatus includes an image projection module, a plurality of projection lenses and an optical path switching module. The optical path switching module is disposed between the image projection module and the projection lenses. The optical path switching module has a light-incident surface and different light-emitting surfaces. An image signal generated by the image projection module enters the optical path switching module through the light-incident surface. The optical path switching module includes a plurality of polarization beam splitters and a polarization adjusting module. The polarization adjusting module is disposed between the polarization beam splitters. The optical path switching module is used for switching the polarization adjusting module time-sequentially for guiding the image signal to those different light-emitting surfaces respectively, and accordingly a plurality of image formation beams are formed from the light-emitting surfaces though the projection lenses.

Abstract: A stereo display apparatus includes a support member, at least one projector, a screen, first reflectors, and an actuator. The projector is connected to the support member, and includes a battery and an image memory module. The projector is capable of emitting an image beam. The screen is connected to the support member. The first reflectors surround the support member. The actuator is connected to the support member and is capable of driving the support member to rotate. The support member is capable of driving the projector and the screen to rotate. When the projector and the screen rotate, the image beam is projected onto the first reflectors in sequence, and the first reflectors reflect the image beam onto the screen in sequence.

Abstract: A 3D display is provided comprising at least one light source, a Switchable Bragg Grating device, a microdisplay and a projection lens system. In one embodiment of the invention the SBG device converts the source light into colour sequential illumination and, and provides sequential orthogonally polarized illumination of the microdisplay for each colour. In one embodiment of the invention the first SBG device converts the source light into colour sequential illumination and, and provides sequential first and second sense circularly polarized illumination. The microdisplay is updated with alternating left and right eye perspective images for stereoscopic viewing.

Abstract: Generally, near seamless electronics displays may be employed in cinema and exhibition applications. Laser scanned displays may be enabled such that the display may display three dimensional (“3D”) content. A first method to enable a laser scanned display for 3D content may employ polarization, with or without polarization conversion and another method may employ multiple colors. Additionally, the envelope function that may be employed across the display may be achieved by changing laser power as a beam is scanned on the screen or by changing the dwell time of the laser beam on the pixels. One method of minimizing the effects of seams in the screen may be to reduce the screen resolution near the seams by screen design and/or laser beam dwell time or illumination energy.

Abstract: A projection stereoscopic display includes: a stereoscopic display optical system receiving linearly polarized light from the light source and displaying a first picture and a second picture both having binocular parallax by linearly polarized light with polarization directions orthogonal to each other, in which the stereoscopic display optical system includes: a reflective liquid crystal panel modulating and reflecting linearly polarized light from the light source in response to a picture signal, a first polarizing device splitting the first picture from reflected light from the reflective liquid crystal panel, a retardation device converting the polarization direction of the first picture into a direction orthogonal thereto, and a second polarizing device splitting the second picture from reflected light from the reflective liquid crystal panel, and superimposing the second picture on the first picture of which the polarization direction is converted by the retardation device.

Abstract: Disclosed herein are optical projection systems and related methods for projecting imagery employing shifting image position in-time to mitigate speckle. Exemplary optical systems may include a projector having a light source, a relay lens and at least one projection lens for projecting images. The relay lens or the projection lens may have at least one lens element that may be translated in-time substantially orthogonal to the optical axis of the optical system. Alternatively, the projection lens in its entirety may be shifted in-time to reduce speckle. Further, in stereoscopic embodiments, two projection lenses may be employed, wherein at least one element in each projection lens is moveable to shift the image in-time to reduce speckle. Moreover, electronic compensation, such as electronic addressing or image warping, for the image shifting may be employed to shift the image in a direction opposite to the speckle-reducing shift in position.

Abstract: A system for stereoscopic cinema projection comprising at least one projector for projecting two images, one image for a first eye and one image for a second eye of a viewer, is proposed. The beam paths of the light emerging from the projector respectively run through a linear polarizer to a correspondingly assigned projection lens. After passing through the projection lens, the beam paths of the two images, which are different for the eyes of a viewer, run through a radial and respectively a tangential polarization filter and are simultaneously projected, with different polarization states, exactly one on top of the other onto a metallic projection wall. By means of a visual aid for both eyes of a viewer, the lenses of which are configured differently for each eye with a radial and respectively a tangential polarization filter, each partial image is made visible only for the first or left eye or the second or right eye (or vice versa) and the 3D impression is thus generated for the viewer.

Abstract: Three dimensional projection systems may be single projector or multiple projector systems. These 3D projection systems may include a one or more polarization conversion systems (PCS). Each PCS may be designed for relatively small throw ratios and thus, may be designed to accommodate the small throw ratios. Each PCS may include a polarizing beam splitter, a first optical stack, a reflector and a second quarter wave retarder. The first optical stack may include a rotator, a polarizer, a polarization switch and a first quarter wave retarder. Each PCS may receive light from a respective projector, and the PBS in each PCS may direct the light toward the first optical stacks. The light may be converted to a different polarization state as it passes through the first optical stack. The converted light may then be re-directed by a reflecting element to a second quarter wave retarder. The second quarter wave retarder may convert linearly polarized light to circularly polarized light.

Abstract: The present invention discloses a stereoscopic image display system and a method of controlling the same. An eye tracking module locates current 3D spatial positions of the viewer's eyes, and generates the information of both left and right eyes' current 3D spatial positions. A control module controls a display device that can alter the direction of the light outputted, and outputs images on the display device in time multiplex mode. The light containing the left eye image is outputted to the position of left eye instead of right eye at one time point, and the light containing the right eye image is outputted to the position of right eye instead of left eye at another time point, so that a stereoscopic image is perceived according to the parallax theory. The present invention enlarges the visual range of stereoscopic image and achieves a better stereoscopic image visual experience for viewers.

Abstract: A multi-segment optical retarder that can be used with or within a single projector for creating 3D images. The multi-segment optical retarder is coupled to an actuator used to effect some predetermined linear, rotary, or oscillating movement of the multi-segment optical retarder such that a fast axis orientation of each segment is substantially constant relative to itself over time and for a given area of incidence.

Abstract: Proposed are various embodiments of projection systems that generally provide stereoscopic images. The projection systems act to split a spatially separated image in a stereoscopic image frame and superimpose the left- and right-eye images on a projection screen with orthogonal polarization states. The embodiments are generally well suited to liquid crystal polarization based projection systems and may use advanced polarization control.

Abstract: Systems and methods configured for outputting light having a polarization state distribution that is spatially uniform by applying a correction to, for example, a beam of light with a spatially uniform polarization state distribution that has been altered (unintentionally or otherwise) to become spatially non-uniform are described. A projection system can include an optical element and a polarization-altering device (PAD). The optical element can cause a polarization of light in the projection system to be spatially non-uniform. The PAD can change the polarization state distribution of the light spatially based on an amount of spatial non-uniformity on the light caused by the optical element and before the light enters the optical element. The projection system can output the light having a spatially uniform polarization state distribution.

Abstract: A method of displaying an image on a screen having upper and lower extremities to a viewer located in front of the screen and at a horizontal distance from the screen, the method comprising the steps of: (a) inclining the screen at an angle of 60° or less to a horizontal plane behind the screen; (b) arranging the viewer and screen such that the upper extremity of the screen is further away than its lower extremity from the point of view of the viewer with said upper extremity above the head height of the viewer; and, (c) displaying the image on the screen.

Abstract: A polarization switch provides substantially ideal binary polarization switching over a broad range of wavelengths using a polarization modulation wheel having at least one retarder stack that transforms polarization. Using the polarization modulation wheel in a polarization system provides a high throughput polarization switch and operates over a wide range of incidence angles while providing substantially continuous and smooth polarization output for each component for any selected polarization basis set. The polarization modulation wheel is well-suited for stereoscopic polarized projection applications.

Abstract: A projection display device includes a first display panel (23a), a second display panel (23b), a PBS (Polarization Beam Splitter) (22) with a first surface (22a) and a second surface (22b) opposite each other, a light recycling device (25a, 25b and 23b), and a projection lens (24). The PBS (22) transmits a first type parallel polarized light and reflects a second type parallel polarized light. The light recycling device (25a, 25b and 23b) transforms the first type parallel polarized light transmitted by the PBS (22) into the second type parallel polarized light which carries a second image information, then reversely transmits the second type parallel polarized light to the second surface (22b) of the PBS (22).The projection display device improves the light utilization efficiency and can be used for 3D display.

Abstract: Projection systems and methods for providing stereoscopic images viewed through passive polarizing eyewear. The systems relate to projectors that create left and right eye images simultaneously and often as side-by-side images on the image modulator. The systems act to superimpose the spatially separated images on a projection screen with alternate polarization states. The embodiments are best suited to liquid crystal polarization based projection systems and use advanced polarization control.

Abstract: A projection apparatus has a first light beam having a first state of polarization and containing a first set of primary colors, a first light modulator arrangement for spatially modulating the polarization state of the first light beam to encode a first image thereon in the first set of primary colors, a second light beam having a second state of polarization and containing a second set of primary colors, and a second light modulator arrangement for spatially modulating the polarization state of the second light beam to encode a second image thereon. A polarizing beam splitter having first and second input ports to admit the first and second encoded light beams. Light of one polarization state incident on the first port is transmitted to the output port and light of another polarization state incident on the second port is reflected to said output port so that said transmitted and reflected light is combined into a common output beam at said output port.

Abstract: An imaging system (300) configured to reduce perceived flicker in three-dimensional images is provided. The imaging system (300) can include a plurality of light sources (305,306,307), a light combiner (302), a light modulator (303) and a polarization rotator (301). The light combiner (302) combines light received from each of the light sources into a combined beam (304). A first light portion (313) in the combined beam has a first light portion polarization state that is different from a second light portion polarization state of a second light portion (314). The light modulator (303) produces images by modulating the combined beam (304) along a projection surface (316). The polarization rotator (301) selectively rotates a polarization state of the combined beam (304) in synchrony with an image refresh cycle of the imaging system. A circular polarizer (1004) can be used to transform linear polarization states to circular polarization states.

Abstract: A display apparatus including an image generator, a projection lens set, a depth detecting module detecting the position of user, and a control unit is provided, wherein the control unit is electrically connected to the image generator, the projection lens set and the depth detecting module. An image displayed by the image generator is projected through the projection lens set and generates a floating real image between the projection lens set and the user. Each beam forming the floating real image has a light-cone angle ?. The image generator and the projection lens adjust the position of the floating real image according to the position of user.

Abstract: Three dimensional projection systems may be single projector or multiple projector systems. These 3D projection systems may include a polarization conversion system (PCS). The PCS may be designed for relatively small throw ratios and thus, may be designed to accommodate the small throw ratios. The PCS may include a polarizing beam splitter, a first optical stack, a reflector and a second quarter wave retarder. The first optical stack may include a rotator, a polarizer, a polarization switch and a first quarter wave retarder. The PCS may receive light from a projector and the PBS may direct the light toward the first optical stack. The light may be converted to a different polarization state as it passes through the first optical stack. The converted light may then be re-directed by a reflecting element to the second quarter wave retarder. The second quarter wave retarder may convert linearly polarized light to circularly polarized light.

Abstract: A projector includes: a light source which emits light; a light modulating device which modulates the light emitted from the light source according to image information; an image forming system which forms an image corresponding to the optical image formed by the light modulating device of modulated light which is modulated by the light modulation device at an image forming position; a polarized light emitting unit disposed at the image forming position of the image forming system to selectively convert the polarization direction of a part of entering light; and a projecting device which projects the light from the polarized light emitting unit.

Abstract: Disclosed embodiments include stereoscopic systems having at least one compensator operable to reduce the sensitivity of polarization control over incidence angle of image source optics and analyzer optics. In an exemplary embodiment, the disclosed compensator is operable to compensate polarization changes induced by optics at either or both the image source subsystem and the analyzer subsystem, in which the polarization changes would be operable to cause leakage at the analyzer subsystem if uncompensated. As such, the disclosed compensators and compensation techniques are operable to reduce leakage at the analyzer subsystem even if the disclosed compensator may be located at the analyzer subsystem.

Abstract: An image display apparatus includes a projector receiving an image signal and projecting image light and a screen including a projection plane of arbitrary shape. The projector and screen are connected with link mechanisms and link mechanisms. The relative position and posture between the projector and the screen are automatically or manually changeable. The relative position and posture between the projector and the screen are measured, and correction parameters for correcting distortion of image light projected from the projector onto the screen are calculated from the previously set viewing position of the viewer and the shape of the projection plane of the projector. Based on the calculated correction parameters, the image signal inputted into the projector is subjected to distortion correction processing. It is therefore possible to allow the viewer to see a clear image even if the position of the screen is changed.

Abstract: Multiple image projection apparatus are described. A cubic multi-prism beam splitter is provided having diagonal interfaces with one or more PBS elements and/or reflective elements positioned thereon. At least first and second spatial light modulators, such as LCoS SLMs, are positioned adjacent the beam splitter cube. The first and second LCoS spatial light modulators and first and second projection optics systems are configured to output a first modulated image from the first LCoS SLM to the first projection optics system and a second modulated image from the second LCoS spatial light modulator to the second projection optics system. In other embodiments, additional LCoS spatial light modulators and light sources produce 3-D images. Addition of sensors permits user interaction with a projected image which is fed back to a controller to optionally change current or future images displayed by the system.

Abstract: An apparatus and method for stereoscopic 3D image projection and viewing using a single projection source, alternating polarization, and passive eyewear. This approach is applicable to frame sequential video created using existing 3D graphics APIs, as well as other video signal formats, and is compatible with existing digital light processor (DLP) technology for both front and rear projection systems. An alternating polarizer filter actuator in the form of a closed feedback loop is used to modulate the projected image. A preferred embodiment enables an existing DLP projection system to be enhanced with 3D capability.

Abstract: An image processing apparatus receives first and second input image signals and generates first and second projection image signals for projecting images from first and second projectors so as to be superimposed on a screen. A storage unit stores, for each projection position on the screen, intensity ratios between projected light from the first and second projectors when viewing from first and second viewing position. An intensity correcting unit adds the first and second input image signals in proportions set for generating the first projection image signal and in proportions set for generating the second projection image signal, according to the stored intensity ratios. The first projection image signal is supplied to the first projector and the second projection image signal is supplied to the second projector.

Abstract: An autostereoscopic display device includes a reflection layer for reflecting at least a portion of incident light, a polarization conversion layer arranged over the reflection layer, and an array of lenticular elements arranged over at least a portion of the polarization conversion layer and including a birefringent material. Light having a first state of polarization is configured to pass through the lenticular element array without substantial lenticular element focusing, where the polarization state is transformed by the polarization conversion layer such that the reflected light has a second state of polarization. Light having the second polarization state passes through the lenticular element array with the lenticular element focusing to provide multiple views to different viewing locations.

Abstract: A stereoscopic digital image projecting system has a light source system energizable to provide polarized illumination having a first polarization state and a beam splitting system alternately generating first and second light beams having different polarization states from the polarized illumination. A combining system has a polarization beam combiner that combines the first and second light beams into a combined light beam. A spatial light modulator is used to modulate the combined light beam in a manner consistent with stereoscopic image data to form a first modulated image from illumination in the combined light beam having the first polarization state and to form a second modulated image from illumination in the combined light beam having the second polarization state. Projection optics are configured to project the first and second modulated images onto a display surface.

Abstract: An optical polarization state modulator assembly for use in a stereoscopic three-dimensional image projection system includes a spatial light modulator, a light source emitting multiple wavelength components of light for incidence on the spatial light modulator, and a projection lens. A polarization converter system cooperates with the spatial light modulator to produce in alternating sequence polarized light carrying first and second perspective view images of a scene in different ones of first and second subframes. A polarization modulator, in response to first and second drive signals, imparts to, respectively, the image-carrying polarized light a first output polarization state during the first subframe and to the image-carrying polarized light a second output polarization state during the second subframe. The image-carrying polarized light in the first and second output polarization states propagates through the projection lens for transmission to an observer.

Abstract: A 3D image convertible projection system for viewing a 3D broadcasting and 3D DVD image, using a general projector that receives a left-eye image and a right-eye image for a 3D image in one frame and projects them toward a projection lens, wherein the left-eye image and the right-eye image in 2D form are magnified so that a vertical magnification rate is 0 and a horizontal magnification rate is 1.5-2.5 times. At the same time the left and right images are divided leftward and rightward through an optical system consisting of first and second curved surface mirrors, and then the images are secondly reflected and magnified to be projected toward a screen. The 3D image can then be viewed using polarization eyeglasses through image division, image horizontal magnification rate, and overlapping projection on a polarization separation screen.

Abstract: A stereoscopic image projection system using a circular polarization filter module is provided. Even though this system uses a single projector, it allows left and right images to have different polarization directions using the circular polarization filter module, thereby reducing crosstalk compared to an LCD-shutter-based system.

Abstract: A stereo 3D projector with the ability to provide the native lumen output of the projector when not in 3D mode. This is accomplished by using two rotating polarizing filters at least partially overlapping, each with at least two or more segments, some of which are fully transparent and at least some of which are polarized linearly or circularly.

Abstract: A peripheral device is coupled to a system bus of an apparatus via a system bus compatible cable, and transmits to an operating system a request to transmit to the output multiple image stream 3D video data and a request to access a video subsystem for monitoring a status of page flip signals. The peripheral device transmits sync signals to at least one output of the peripheral device representing the page flip signals detected in response to monitoring page flip signal status. The apparatus transmits the multiple image stream 3D video data to the output. The multiple image stream 3D video data is received at a stereographic projection apparatus input. Each stream data contains a plurality of frames. The stereographic projection apparatus comprises an alternating polarizing filter, synced with the alternately projecting images, for separately filtering images from each of the image stream 3D video data at different polarization angles.

Abstract: A method and apparatus for extracting synchronization information at the output of a projection apparatus, without modifying its rotating color segmented filter wheel or drive electronics. Three photodiodes, each with a different principle color filter, is placed at the projector output to detect output of the different colors in the filter wheel. An exclusive OR circuit is used to detect white light passing through the filter wheel.

Abstract: A 3D stereographic projection apparatus comprises an input for receiving stereographic image data that includes sync signals corresponding to image streams in the image data. A digital light projector projects the stereographic image data. A motor driven rotating filter has a marker disposed thereon positioned in the path of the projected stereographic image data. The motor driven rotating filter separately polarizes the image streams in the stereographic image data. A motor drive circuit, coupled to the input, receives the sync signals and synchronizes a rotation of the filter with the sync signals. A tach sensor, comprising a light transmitter and detector coupled to the rotating filter, detects the marker and outputs marker signals indicating that the marker is detected.

Abstract: In a stereographic projector that places a single linear polarizing wheel in the light path of the projector to impart a desired polarization state onto the projected light, a method and apparatus for periodically slowing the wheel down while in optimal states, and accelerating through invalid states. Stereo separation is greatly increased providing a marked improvement in visual quality and perceived depth when this invention is applied to such a polarizing filter wheel.

Abstract: An apparatus and method for stereoscopic 3D image projection and viewing using a single projection source, alternating polarization, and passive eyewear. This approach is applicable to frame sequential video created using existing 3D graphics APIs, as well as other video signal formats, and is compatible with existing digital light processor (DLP) technology for both front and rear projection systems. An alternating polarizer in the form of a magnetomechanically resonant polarizing filter actuator is used to modulate the projected image. A preferred embodiment enables an existing DLP projection system to be enhanced with 3D capability.