PHOTOCHROMATIC LENSES

The present invention relates to a system and method for presenting three-dimensional content.

Three-dimensional (3D) imagery may be achieved by presenting content that is resolved into separate images by a viewer's left and right eyes. When the two separate images are received simultaneously, the viewer perceives a three-dimensional image by fusing the images received by the left and right eyes and using parallax to achieve depth perception.

Due to the ubiquity of such displays, it is suggested to use televisions and other display technologies conventionally used to present two- dimensional images and/or video, to provide three-dimensional video. 3-D imagery can be presented on a 2-D display using tinted glasses configured such that each of the viewer's eyes sees a differently tinted (or filtered) image. Another technique involves the use of glasses with differently polarized lenses. Each of these techniques, however, requires the use of specialized glasses or other filters to capture the content being displayed. If the

appropriate eyeglass or other filters are not readily available, then each of these techniques is of limited usefulness. It has also been proposed to use glasses including liquid crystal displays (LCDs) that function like shutters to alternate which eye receives an image being presented on the display. The LCDs require electronics and power to operate, and this increases the size and cost of these headsets.

The present invention seeks to provide systems and methods for presenting three-dimensional content which reduce the limitations of the current techniques.

According to a first aspect of the present invention there is provided a system for presenting a plurality of frames on a display, the system comprising a display, and first and second lenses, and

an activation system arranged to utilize electromagnetic radiation to activate the first lens when a respective frame being presented on the display corresponds to the first lens, resulting in the first lens being substantially transparent and the second lens being substantially opaque, and to activate the second lens when a respective frame being presented on the display corresponds to the second lens, resulting in the second lens being

substantially transparent and the first lens being substantially opaque. In an embodiment, the first lens has a first photosensitivity and the second lens has a second photosensitivity, the first photosensitivity and the second photosensitivity being different.

Preferably, the activation system comprises a source for emitting the electromagnetic radiation, and the activation system is arranged to activate the first lens by emitting the electromagnetic radiation from the source when a first frame corresponding to the first lens is presented on the display.

Generally, the electromagnetic radiation is not visible.

In an embodiment, the first and second lenses are arranged such that the electromagnetic radiation increases transparency of the first lens and increases opacity of the second lens. The electromagnetic radiation may be synchronized with the first frame being presented on the display.

Preferably, the activation system is arranged to activate the second lens by ceasing the emitting of the electromagnetic radiation when a second frame corresponding to the second lens is presented by the display.

In an embodiment, an absence of the electromagnetic radiation increases transparency of the second lens and increases opacity of the first lens.

Preferably, the activation system includes:

a first source arranged to emit electromagnetic radiation comprising a first portion of the electromagnetic spectrum; and

a second source arranged to emit electromagnetic radiation comprising a second portion of the electromagnetic spectrum, wherein the activation system is arranged to: activate the first lens by emitting the electromagnetic radiation from the first source when a first frame corresponding to the first lens is presented by the display; and

activate the second lens by the emitting electromagnetic radiation from the second source when a second frame corresponding to the second lens is presented by the display.

Generally, the first and second portions of the electromagnetic spectrum are not visible.

The present invention also extends to a system comprising:

a processor arranged to present a frame for viewing;

a source arranged to emit electromagnetic radiation; and

a synchronization unit coupled to the source, wherein the

synchronization unit is arranged to signal the source to emit electromagnetic radiation such that the electromagnetic radiation is emitted in sync with the frame being presented.

Preferably, the system further comprises a display coupled to the processor, wherein the processor is arranged to present the frame on the display.

In an embodiment, the electromagnetic radiation is emitted in sync with the frame being presented on the display.

A system of an embodiment may further comprise a photosensitive lens, wherein the electromagnetic radiation increases transparency of the photosensitive lens. Preferably, the system further comprises a second photosensitive lens, wherein the electromagnetic radiation increases opacity of the second photosensitive lens.

According to a further aspect of the present invention there is provided a method of presenting three-dimensional content comprising a plurality of frames, wherein each frame corresponds to either a first eye of a prospective viewer or a second eye of the prospective viewer, the method comprising: displaying the plurality of frames on a display; activating a first lens arranged to be aligned with the first eye of the prospective viewer when a respective frame on the display corresponds to the first eye; and

activating a second lens arranged to be aligned with the second eye of the prospective viewer when a respective frame on the display corresponds to the second eye.

In an embodiment,

activating the first lens comprises increasing transparency of the first lens; and

activating the second lens comprises increasing transparency of the second lens.

Preferably,

activating the first lens comprises decreasing transparency of the second lens; and

activating the second lens comprises decreasing transparency of the first lens.

In an embodiment, activating the first lens comprises emitting electromagnetic radiation, the first lens being substantially transparent and the second lens being substantially opaque in response to the electromagnetic radiation. Additionally and/or alternatively, activating the first lens comprises ceasing emitting electromagnetic radiation, the first lens being substantially transparent and the second lens being substantially opaque in response to an absence of the electromagnetic radiation. Embodiments of the invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a block diagram of a system for presenting three- dimensional content;

FIG. 2 shows a block diagram of a further system for presenting three- dimensional content;

FIG. 3 and FIG. 4 shows an activation system and a pair of lenses suitable for use in a system as illustrated in FIG. 1 or FIG. 2; FIG. 5 and FIG. 6 shows an activation system and a pair of lenses suitable for use in a system as illustrated in FIG. 1 or FIG. 2; and

FIG. 7 is a flowchart illustrating a method for presenting three- dimensional video.

Systems and methods for presenting three-dimensional ("3D" or "3-D") imagery to a viewer are described herein. Photosensitive (or reactive) lenses are used to allow a viewer to perceive different sets of imagery through the left and right eyes respectively, thereby creating a stereoscopic effect. The lenses have different photosensitivity, and so, in response to a particular spectrum of electromagnetic radiation, one lens is substantially transparent while the other is substantially opaque. In this respect, a lens is substantially transparent when the opacity of the lens has a negligible impact on a viewer's perception through the lens, and a lens is substantially opaque when the opacity of the lens results in negligible perception through the lens. The transparency/opacity of the lenses may be alternated in sync with the content being displayed, such that content designated for the left eye of the viewer is perceived through the lens aligned with the viewer's left eye and content designated for the right eye of the viewer is perceived through the lens aligned with the viewer's right eye.

FIG. 1 illustrates a system 100 for presenting three-dimensional content which includes a receiver system 102, a display system 104, a head- mountable device 106 including a pair of lenses 1 18, and an activation system 108. The display system 104 includes a processor 1 12 coupled to the receiver system 102 and for presenting images and/or video corresponding to the content received by the receiver system 102 from the content source 1 10 on a display 1 14. The lenses 1 18 may comprise reactive lenses (or alternatively, photosensitive lenses or light-sensitive lenses) that are aligned with the eyes of a viewer and interposed in the viewer's line of sight between the viewer and the display 1 14. The activation system 108 emits

electromagnetic radiation 124 in sync with frames being presented on the display 1 14 to vary the transparency and/or opacity of the lenses 1 18 and achieve stereoscopic imaging.

The receiver system 102 generally represents the devices,

components, circuitry and/or logic capable of receiving and processing video content from a content source 1 10. The content source 1 10 may provide video content to the receiver system 102 over any sort of broadcast or other distribution channel, such as, for example, broadcast television, very small aperture terminal (VSAT) satellite (e.g., for movie distribution), direct broadcast satellite (DBS), cable television, cellular or other wireless telephone networks, Internet or other data communications networks, physical media, and/or another suitable avenue for delivering content.

The video content provided by the content source 1 10 comprises a plurality of video frames that are encoded or otherwise configured for stereoscopic imaging. In this regard, each video frame comprises a still image that is designated for or otherwise intended to be perceived by either a left eye or a right eye of a viewer. The content designated for and/or intended to be perceived by the left eye of a prospective viewer may be referred to herein as the left channel content (or left channel frame) and the content designated for and/or intended to be perceived by the right eye of a prospective viewer may be referred to herein as the right channel content (or right channel frame). The right channel video frames may comprise images captured by a first camera and the left channel video frames may comprise images captured by a second camera positioned to the left of the first camera, resulting in parallax between the right channel content and the left channel content. Thus, when a viewer perceives the right channel content with his or her right eye and the left channel content with his or her left eye at the same time, the parallax results in the viewer perceiving depth, thereby producing a three-dimensional image. The right channel frames and the left channel frames are spliced such that the content provided by the content source 1 10 comprises frames that alternate between the right channel and the left channel, also known as alternate-frame sequencing. For example, a first (or initial) frame of the content from the content source 1 10 may be encoded or otherwise designated for the right eye, a second frame subsequent the first frame may be encoded or otherwise designated for the left eye, a third frame subsequent the second frame may be encoded or otherwise designated for the right eye, and so on. The frame rate of the video content provided by the content source 1 10 is greater than 30 Hz (or 30 frames per second), such that each eye perceives its corresponding frames at a rate of at least 15 frames per second to create the illusion of a moving picture with limited flickering or other visual artifacts that may otherwise be perceptible at lower frame rates. The synchronized sequential presentation of a right channel frame to the right eye and a left channel frame to the left eye provides the viewer the impression that the sequential right channel and left channel frames are being presented on the display 1 14 simultaneously, resulting in a three-dimensional image. Each lens 1 18 is photosensitive and has variable transparency and/or opacity, wherein the transparency and/or opacity of a respective lens 1 18 is influenced by the presence and/or absence of a particular spectrum of electromagnetic radiation. The transparency and opacity of the lenses 1 18 are controlled by electromagnetic radiation 124 emitted by the activation system 108, as described in greater detail below. In an exemplary

embodiment, the lenses 1 18 are configured such that the lens aligned with the right eye of the viewer (e.g., the right lens) is substantially transparent while the lens aligned with the left eye of the viewer (e.g., the left lens) is

substantially opaque, and the right lens is substantially opaque while the left lens is substantially transparent. For example, one lens (e.g., the left lens) may comprise a photochromatic material that is transparent in the absence of ultraviolet radiation and opaque in the presence of ultraviolet radiation, and the other lens (e.g., the right lens) may comprise an inverse photochromatic material that is opaque in the absence of ultraviolet radiation and transparent in the presence of ultraviolet radiation. The activation system 108 may emit ultraviolet radiation in sync with a right channel frame being presented on the display 1 14 to cause the left lens to be opaque and the right lens to be transparent when the right channel frame is presented on the display 1 14, and the activation system 108 may cease emitting ultraviolet radiation in sync with a left channel frame being presented on the display 1 14 to cause the right lens to be opaque and the left lens to be transparent when the left channel frame is presented on the display 1 14.

As shown in FIG. 1 , the head-mountable device 106 includes a support structure 1 16 adapted to be worn on the head of a viewer of display 1 14 and configured to support and/or house the pair of lenses 1 18 such that the lenses 1 18 are aligned with the eyes of the viewer. In other words, the lenses 1 18 are interposed in the viewer's line of sight between the viewer and the display 1 14 when the support structure 1 16 is worn on the user's head. The support structure 1 16 may be realized as an eyeglass frame. Additionally and/or alternatively, the support structure 1 16 may be realized as a helmet, goggles, mask, visor, or the like, and may include straps or other elements to provide support and/or comfort to a user. The lenses 1 18 may also be realized as contact lenses (e.g., lenses placed on the cornea of the eye), and in such a case, the system 100 need not include a head-mountable device 106 and/or support structure 1 16. The activation system 108 provides electromagnetic radiation 124 that causes one lens of the pair of lenses 1 18 to be substantially opaque while the other lens of the pair of lenses 1 18 is substantially transparent. The activation system 108 includes a synchronization unit 120 and one or more source(s) 122 configured to emit electromagnetic radiation 124. The source(s) 122 are positioned proximate to and/or adjacent to the display 1 14 such that the source(s) 122 are within a field of a view of a viewer when viewing the display 1 14. The source(s) 122 are realized as one or more non-visible light source(s) that emit electromagnetic radiation 124 in the non-visible portion of the electromagnetic spectrum under control of the synchronization unit 120. The non-visible light source(s) 122 emit electromagnetic radiation 124 diffusely to accommodate movement by a viewer wearing the head-mountable device 106 when viewing the display 1 14. The power level of the

electromagnetic radiation 124 is chosen to satisfy a desired distance between the source(s) 122 and a prospective viewer, and in practice, the power level of the electromagnetic radiation 124 may vary depending on the needs of a particular embodiment.

The synchronization unit 120 generally represents the hardware, firmware and/or software (or combinations thereof) suitably configured to control the timing of the electromagnetic radiation 124 provided by the activation system 108 and/or non-visible light source(s) 122 such that the transparency and opacity of the lenses 1 18 are synchronized with the content being presented on the display 1 14. In this regard, the synchronization unit 120 controls the non-visible light source(s) 122 such that the right lens of the pair of lenses 1 18 is substantially transparent and the left lens of the pair of lenses 1 18 is substantially opaque when content corresponding to the right eye (or right channel) is presented for viewing on the display 1 14.

Conversely, the synchronization unit 120 controls the non-visible light source(s) 122 such that the left lens of the pair of lenses 1 18 is substantially transparent and the right lens of the pair of lenses 1 18 is substantially opaque when content corresponding to the left eye (or left channel) is presented for viewing on the display 1 14. The processor 1 12 generally represents the hardware, firmware and/or software (or combinations thereof) suitably configured to present images on the display 1 14 that correspond to the frames of the content received by the receiver system 102. The processor 1 12 may be implemented using any sort of microprocessor, microcontroller, digital signal processor or other logic capable of controlling the functionality and/or otherwise interacting with the display 1 14. The processor 1 12 may also be associated with a suitably configured memory, such as any sort of static, dynamic, flash or other memory capable of storing programming instructions and/or data for processing by processor 1 12. In various embodiments, processor 1 12 may be realized using a "system on chip" (SoC) implementation that incorporates a hybrid

microcontroller with memory, an application specific integrated circuit (ASIC), or another suitable integrated hardware implementations. The display 1 14 may be realized as any sort of television, monitor and/or other display capable of presenting images to a viewer. Preferably, the display 1 14 operates in conjunction with the processor 1 12 to generate images corresponding to the frames of the content received by the receiver system 102. As illustrated in FIG. 1 , the synchronization unit 120 may be coupled to the processor 1 12, and arranged to control the timing of the non-visible light source(s) 122 such that the appropriate electromagnetic radiation 124 is emitted (or ceases being emitted) in sync with the content being presented on the display 1 14.

Although FIG. 1 depicts the receiver system 102, the display system 104, and the activation system 108 as discrete components, it is alternatively possible to realize the receiver system 102, the activation system 108 and/or processor 1 12 as an integrated product (e.g., a set-top box) or the activation system 108 and the display 1 14 and/or display system 104 may be realized as an integrated product (e.g., a television). In practice, the system 100 may include numerous other devices and components for providing additional functions and features. Conventional techniques related to image processing, video processing, video encoding and/or decoding, stereoscopic imaging, and other functional aspects of the systems (and the individual operating

components of the systems) are not further described. FIG. 2 depicts an alternative system 200 for presenting three- dimensional content. Various elements of the system 200 of FIG. 2 are similar to counterpart elements described above in the context of the system 100 of FIG. 1 , and are not further described. The system 200 illustrated in FIG. 2 includes an activation system 208 with a synchronization unit 220 that is configured to synchronize the electromagnetic radiation 124 emitted by the non-visible light source(s) 122 with the image presented by the display 1 14 by sensing or otherwise detecting the frame being presented by the display 1 14. The synchronization unit 220 is coupled to one or more opto sensors 230 configured to sense or otherwise detect whether the display 1 14 is currently presenting a frame designated and/or encoded for the right eye (or right channel) or a frame designated and/or encoded for the left eye (or left channel). For example, each frame may include a sync graphic in the upper corner of the frame that oscillates between a first state for frames corresponding to a first channel and a second state for frames corresponding to a second channel. The left channel frames may include a white sync graphic and the right channel frames may include a black sync graphic. In response to sensing or detecting a frame presented by the display 1 14 that corresponds to the right eye (or right channel), for example, by the opto sensor 230 detecting a black sync graphic, the synchronization unit 220 controls the non-visible light source(s) 122 such that the right lens of the pair of lenses 1 18 is substantially transparent and the left lens of the pair of lenses 1 18 is substantially opaque. Conversely, in response to sensing or detecting a frame presented by the display 1 14 that corresponds to the left eye (or left channel), for example, by the opto sensor 230 detecting a white sync graphic, the synchronization unit 120 controls the non-visible light source(s) 122 such that the left lens of the pair of lenses 1 18 is substantially transparent and the right lens of the pair of lenses 1 18 is substantially opaque.

FIG. 3 and FIG. 4 depict an activation system 300 and a pair of lenses 306 suitable for use as the activation system 108, 208 and pair of lenses 1 18 in the system 100 of FIG. 1 or the system 200 of FIG. 2. In FIG. 3 and FIG. 4, the activation system 300 and pair of lenses 306 are arranged for operation with a single non-visible light source 304. In this regard, the lenses 306 are inversely reactive, such that in response to a spectrum of electromagnetic radiation 312, a first lens 308 is substantially transparent while the second lens 310 is substantially opaque, while in response to the absence of the spectrum of electromagnetic radiation 312, the first lens 308 is substantially opaque while the second lens 310 is substantially transparent. For example, one lens 310 (e.g., the lens aligned with the left eye of the viewer) may comprise a photochromatic material that is configured to be substantially transparent under ambient lighting conditions in the absence of

electromagnetic radiation 312 from the non-visible light source 304 and the other lens 308 (e.g., the lens aligned with the right eye of the viewer) may comprise an inverse photochromatic material that is opaque under ambient lighting conditions in the absence of electromagnetic radiation 312 from the non-visible light source 304.

As shown in FIG. 3, the lenses 308, 310 are sensitive to the spectrum of electromagnetic radiation 312 emitted by the non-visible light source 304, such that in response to the spectrum of electromagnetic radiation 312 being emitted by the non-visible light source 304, the transparency of the first lens 308 increases to the point where the first lens 308 is substantially transparent while the opacity of the second lens 310 increases until the second lens 310 is substantially opaque. In other words, the electromagnetic radiation 312 emitted by the non-visible light source 304 increases the transparency of the first lens 308 and increases the opacity of the second lens 310. In the illustrated embodiment, the non-visible light source 304 may be realized as an ultraviolet light-emitting diode (LED) that provides electromagnetic radiation 312 comprising a portion of the ultraviolet spectrum, such as, for example, ultraviolet radiation having wavelengths of about 315 nanometers to about 400 nanometers. As shown in FIG. 4, the non-visible light source 304 emits electromagnetic radiation 312 diffusely. The activation system 300 includes a synchronization unit 302 that synchronizes the emission of electromagnetic radiation 312 from the non- visible light source 304 with the content presented on the display 1 14. In this regard, when a frame of the received content that is designated for the right channel (or right eye) is presented on display 1 14, the synchronization unit 302 activates the lens aligned with the viewer's right eye (e.g., lens 308) and deactivates the lens aligned with the viewer's left eye (e.g., lens 310) by signaling the non-visible light source 304 to emit electromagnetic radiation 312, causing the viewer's right lens 308 to become substantially transparent and the viewer's left lens 310 to become substantially opaque as shown in FIG. 4. Conversely, when a frame of the received content that is designated for the left channel (or left eye) is presented on display 1 14, the

synchronization unit 302 activates the lens aligned with the viewer's left eye (e.g., lens 310) and deactivates the lens aligned with the viewer's right eye (e.g., lens 308) by signaling the non-visible light source 304 to cease emitting electromagnetic radiation 312, thereby causing the viewer's right lens 308 to become substantially opaque and the viewer's left lens 310 to become substantially transparent as shown in FIG. 3. In this manner, the activation system 300 alternately activates and/or deactivates the pair of lenses 306 by emitting and/or ceasing emitting electromagnetic radiation 312 in sync with the displayed content to provide three-dimensional imagery to the viewer stereoscopically. Thus, the activation system 300 controls the pair of lenses 306 such that the right eye of the viewer perceives frames encoded or otherwise designated for the right eye (or right channel) and negligibly perceives (e.g., little or no perception of) frames encoded or otherwise designated for the left eye (or left channel) and the left eye of the viewer perceives frames encoded or otherwise designated for the left eye and negligibly perceives frames encoded or otherwise designated for the right eye. When the frame rate is great enough such that the viewer perceives the right channel and left channel as being displayed simultaneously, the

synchronization of the frames and lenses produces a stereoscopic effect.

FIG. 5 and FIG. 6 show an activation system 500 and a pair of lenses 508 suitable for use as the activation system 108, 208 and pair of lenses 1 18 in the system 100 of FIG. 1 or the system 200 of FIG. 2. The activation system 500 and pair of lenses 508 are arranged for operation with two non- visible light sources 504, 506. In this regard, each non-visible light source 504, 506 is configured to emit electromagnetic radiation over a different portion of the electromagnetic spectrum. For example, the first non-visible light source 504 may emit electromagnetic radiation 514 over a first portion of the electromagnetic spectrum and the second non-visible light source 506 may emit electromagnetic radiation 516 over a different portion of the electromagnetic spectrum. In this regard, the portion of the electromagnetic spectrum emitted by the first non-visible light source 504 and the portion of the electromagnetic spectrum emitted by the second non-visible light source 506 are mutually exclusive, that is, the non-visible light sources 504, 506 do not emit electromagnetic radiation having the same wavelength and/or frequency as electromagnetic radiation emitted by the other light source 504, 506.

As shown in FIG. 5, a first lens 510 (e.g., the lens aligned with the right eye of the viewer) of the pair of lenses 508 is configured to be substantially opaque while the second lens 512 (e.g., the lens aligned with the left eye of the viewer) is configured to be substantially transparent when electromagnetic radiation 514 over a first portion of the electromagnetic spectrum that is emitted from the first non-visible light source 504 and electromagnetic radiation 516 over a second portion of the electromagnetic spectrum is not emitted by the second non-visible light source 506. As shown in FIG. 6, when electromagnetic radiation 516 over a second portion of the electromagnetic spectrum is emitted by the second non-visible light source 506 and

electromagnetic radiation 514 over the first portion of the electromagnetic spectrum is not emitted from the first non-visible light source 504, the first lens 510 (e.g., the lens aligned with the right eye of the viewer) becomes

substantially transparent while the second lens 512 (e.g., the lens aligned with the left eye of the viewer) becomes substantially opaque.

As described above, the activation system 500 includes a

synchronization unit 502 that synchronizes the emission of electromagnetic radiation 514, 516 from the non-visible light sources 504, 506 with the content presented on the display 1 14. In this regard, when a frame of the received content that is designated for the right channel (or right eye) is presented on the display 1 14, the synchronization unit 502 activates the lens aligned with the viewer's right eye (e.g., lens 510) and deactivates the lens aligned with the viewer's left eye (e.g., lens 512) by signaling the first non-visible light source 504 to cease emitting electromagnetic radiation 514 and signaling second non-visible light source 506 to emit electromagnetic radiation 516, causing the viewer's right lens 510 to become substantially transparent and the viewer's left lens 512 to become substantially opaque as shown in FIG. 6. Conversely, when a frame of the received content that is designated for the left channel (or left eye) is presented on the display 1 14, the synchronization unit 502 activates the lens aligned with the viewer's left eye (e.g., lens 512) and deactivates the lens aligned with the viewer's right eye (e.g., lens 510) by signaling the first non-visible light source 504 to emit electromagnetic radiation 514 and signaling second non-visible light source 506 to cease emitting electromagnetic radiation 516, causing the viewer's right lens 510 to become substantially opaque and the viewer's left lens 512 to become substantially transparent as shown in FIG. 5. In this manner, the activation system 500 alternately activates and/or deactivates the pair of lenses 508 in sync with the displayed content to provide three-dimensional imagery to the viewer stereoscopically. The opacity of the first lens 510 may increase either in response to the electromagnetic radiation 514 over the first portion of the electromagnetic spectrum or in response to the absence of electromagnetic radiation 516 over the second portion of the electromagnetic spectrum. Similarly, the

transparency of first lens 510 may increase either in response to the electromagnetic radiation 516 over the second portion of the electromagnetic spectrum or in response to the absence of electromagnetic radiation 514 over the second portion of the electromagnetic spectrum. In a similar manner, the opacity of the second lens 512 may increase either in response to the electromagnetic radiation 516 over the second portion of the electromagnetic spectrum or in response to the absence of electromagnetic radiation 514 over the first portion of the electromagnetic spectrum, and the transparency of the second lens 512 may increase either in response to the electromagnetic radiation 514 over the first portion of the electromagnetic spectrum or in response to the absence of electromagnetic radiation 516 over the second portion of the electromagnetic spectrum.

A system 100, 200 may perform a three-dimensional video presentation process 700 as shown in FIG. 7, and other tasks, functions, and operations. The various tasks may be performed by software, hardware, firmware, or any combination thereof. For illustrative purposes, the following description refers to elements discussed above in connection with FIGS. 1 -6. In practice, the tasks, functions, and operations may be performed by different elements of the described system, such as the display system 104, the activation system 108, 208, 300, 500, the processor 1 12, the display 1 14, the lenses 1 18, 306, 508, the synchronization unit 120, 220, 302, 502, and/or the non-visible light source(s) 122, 304, 504, 506. It will also be appreciated that any number of additional or alternative tasks may be included, and may be incorporated into a more comprehensive procedure or method having additional functionality not described herein.

Referring again to FIG. 7, and with continued reference to FIGS. 1 -6, a three-dimensional video presentation process 700 may be performed to present three-dimensional video to a viewer on a display. The three- dimensional video presentation process 700 begins by receiving three- dimensional content for display (task 702). In this regard, the processor 1 12 and synchronization unit 120, 220 receive video content comprising a plurality of frames from a content source 1 10 via the receiver system 102. The alternating frames of the received content are encoded or otherwise designated for opposite eyes of a prospective viewer to support the

stereoscopic imaging techniques described herein. The three-dimensional video presentation process 700 continues by displaying the received content on the display (task 704). In this regard, the processor 1 12 generates images corresponding to the frames of the received content on the display 1 14 in a conventional manner.

The three-dimensional video presentation process 700 continues by alternately activating the lenses of a head-mountable device being worn by a viewer in sync with the displayed content (task 706). The synchronization unit 120, 220, 302, 502 controls the timing of the electromagnetic radiation emitted by the non-visible light source(s) 122, 304, 504, 506 such that the

substantially transparent lens of the pair of lenses 1 18, 306, 508 corresponds to the designated eye of the viewer for the frame being presented on the display 1 14. The lenses 1 18, 306, 508 are activated in sync with the displayed content, such that when the display 1 14 changes from displaying a frame designated for the right eye (or right channel) to displaying a frame designated for the left eye (or left channel), the lens aligned with the viewer's left eye changes from being substantially opaque to being substantially transparent and the lens aligned with the viewer's right eye changes from being substantially transparent to being substantially opaque, and vice versa. In an exemplary embodiment, the synchronization unit 120, 220 receives frames from the receiver system 102 and determines whether the frame being presented on the display 1 14 corresponds to the right eye (or right channel) or the left eye (or left channel).

The synchronization unit 120 may be coupled to the processor 1 12 and synchronize the non-visible light source(s) 120 with the display 1 14 by accounting for the amount of time required for the processor 1 12 to process a frame received from the receiver system 102 and present the image corresponding to the received frame on the display 1 14. Additionally and/or alternatively, the synchronization unit 220 may synchronize the non-visible light source(s) 120 by sensing or otherwise detecting whether the frame presented on the display 1 14 corresponds to the right eye (or right channel) or the left eye (or left channel) to account for the amount of time required for the processor 1 12 to process a frame received from the receiver system 102 and present the image corresponding to the received frame on the display 1 14. ln response to detecting or otherwise determining a frame designated for a viewer's right eye is being presented on the display 1 14, the

synchronization unit 120, 220 activates the lens aligned with the right eye of the viewer by increasing its transparency (or decreasing its opacity) and deactivates the lens aligned with the left eye of the viewer by increasing its opacity (or decreasing its transparency). Conversely, in response to detecting or otherwise determining a frame designated for a viewer's left eye is being presented on the display 1 14, the synchronization unit 120, 220 activates the lens aligned with the left eye of the viewer by increasing its transparency (or decreasing its opacity) and deactivates the lens aligned with the right eye of the viewer by increasing its opacity (or decreasing its transparency). In this manner, the synchronization unit 120, 220 and/or activation system 108, 208 alternately activates either the lens aligned with the right eye of the viewer or the lens aligned with the left eye throughout operation of the system 100, 200.

For example, as illustrated in FIGS. 3-4, in response to detecting or otherwise determining a frame designated for a viewer's right eye is being presented on the display 1 14, the synchronization unit 302 activates the first lens 308 and deactivates the second lens 310 by signaling the non-visible light source 304 to emit electromagnetic radiation 312 in sync with the frame being presented on the display 1 14. In this manner, the emission of electromagnetic radiation 312 by the non-visible light source 304 is synchronized with the presentation of a right channel frame on the display 1 14. In response to detecting or otherwise determining a frame designated for a viewer's left eye is being presented on the display 1 14, the synchronization unit 302

deactivates the first lens 308 and activates the second lens 310 by signaling the non-visible light source 304 to cease emitting electromagnetic radiation 312 in sync with the frame being presented on the display 1 14. Thus, the emission of electromagnetic radiation 312 starts when a right channel frame is presented on the display 1 14 and the emission of electromagnetic radiation 312 stops when a left channel frame is presented on the display 1 14.

Similarly, as illustrated in FIGS. 5-6, in response to detecting or otherwise determining a frame designated for a viewer's right eye is being presented on the display 1 14, the synchronization unit 502 activates the first lens 510 and deactivates the second lens 512 by signaling the second non- visible light source 506 to emit electromagnetic radiation 516 and signaling the first non-visible light source 504 to cease emitting electromagnetic radiation 514 in sync with the frame being presented on the display 1 14. In this manner, the emission of electromagnetic radiation 516 by the non-visible light source 506 is synchronized with the presentation of a right channel frame on the display 1 14. In response to detecting or otherwise determining a frame designated for a viewer's left eye is being presented on the display 1 14, the synchronization unit 502 deactivates the first lens 510 and activates the second lens 512 by signaling the first non-visible light source 504 to emit electromagnetic radiation 514 and signaling the second non-visible light source 506 to cease emitting electromagnetic radiation 516 in sync with the frame being presented on the display 1 14. In this manner, the emission of electromagnetic radiation 514 by the non-visible light source 504 is

synchronized with the presentation of a left channel frame on the display 1 14. Thus, the emission of electromagnetic radiation 516 starts and the emission of electromagnetic radiation 514 stops when a right channel frame is presented on the display 1 14, and the emission of electromagnetic radiation 516 stops and the emission of electromagnetic radiation 514 starts when a left channel frame is presented on the display 1 14. One advantage of the systems and/or methods described is that three- dimensional video and/or images may be presented and viewed using a head- mountable device that does not require built-in electronics or require other additional components, such as, polarizers, for operation. Furthermore, the content being displayed may be captured without using filters that may degrade picture quality.

The systems and components have been described herein in terms of functional and/or logical block components, and with reference to symbolic representations of operations, processing tasks, and functions that may be performed by various computing components or devices. It will be

appreciated that the various block components shown may be realized by any number of hardware, software, and/or firmware components arranged to perform the specified functions. It will be appreciated that modifications to, and variations of, the embodiments as described and illustrated may be made within the scope of the accompanying claims.