JP2014010460A - Video observing device and method for controlling transmission factor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve usability in an optical transmission type HMD capable of changing a transmission factor of light.SOLUTION: In this video observing device 200, an optical transmission type HMD 208 presents an image to be observed in the event of projecting a virtual image on real space. A transmission factor modification section modifies a transmission factor of a light passing through the optical transmission type HMD 208. A shutter controlling section 220 sets a lower limit of a transmission factor of light which can be modified by the transmission factor modification section. The shutter controlling section 220, further including a motion detection section 232 for capturing a change of position coordinate of the stereoscopic video observing device 200, may change the lower limit of a transmission factor of light which can be modified by the transmission factor modification section on the basis of the change of position coordinate captured by the motion detection section 232.

Description

  The present invention relates to a video observation device and a transmittance control method executed by the video observation device.

  2. Description of the Related Art In recent years, technological development for presenting stereoscopic images has progressed, and a head mounted display (hereinafter referred to as “HMD”) capable of presenting stereoscopic images with depth has become widespread. Among these HMDs, we have also developed an optically transmissive HMD that uses a holographic element, a half mirror, etc. to present stereoscopic images to the user and allows the user to see the outside of the HMD in a see-through manner. Has been.

  Further, as the performance of television monitors has been improved, three-dimensional monitors capable of presenting stereoscopic images with depth have become widespread. Unlike a conventional monitor that displays a two-dimensional image, the image presented by the three-dimensional monitor is a three-dimensional image having a depth in the front-rear direction. There are various methods for realizing such a three-dimensional monitor. As an example, a frame-sequential three-dimensional monitor that alternately displays a left-eye parallax image and a right-eye parallax image in a time-sharing manner. Is mentioned. The user can observe a stereoscopic image by observing the image through shutter glasses including a shutter that opens and closes in synchronization with the display of the frame sequential type three-dimensional monitor.

  The inventor of the present application recognizes the possibility of presenting a stereoscopic image on both the three-dimensional monitor and the HMD by providing the optically transmissive HMD with an optical shutter for observing the frame sequential three-dimensional monitor. It came. Even when the three-dimensional monitor is not observed, by using an optical shutter, the amount of external light incident on the optically transmissive HMD can be adjusted to recognize the possibility of improving the visibility of the HMD image. It came.

  When adjusting the amount of external light incident on the optically transmissive HMD using an optical shutter, if external light is unexpectedly blocked while the user is looking through the outside of the HMD, the user will see Suddenly the appearance of the outside world becomes invisible, which may be confusing to the user.

  This invention is made | formed in view of such a subject, The objective is to provide the technique which improves the usability in the optical transmission type HMD which can change the transmittance | permeability of light.

  In order to solve the above problems, an aspect of the present invention is a stereoscopic image observation device. The stereoscopic image observation device includes an optical transmission type HMD that presents an image observed when a three-dimensional image in a virtual three-dimensional space is projected into a real space, and transmission of light transmitted through the optical transmission type HMD. A transmittance changing unit that changes the rate; and a shutter control unit that sets a lower limit value of the light transmittance that can be changed by the transmittance changing unit.

  Another aspect of the present invention is a transmittance control method. This method includes a step of acquiring a change in position coordinates of an optically transmissive HMD that presents an image observed when a three-dimensional image in a virtual three-dimensional space is projected into a real space; Based on the change, the processor controls a transmittance changing unit provided in the optical transmission HMD to set a lower limit value of the transmittance of light transmitted through the optical transmission HMD.

  Yet another embodiment of the present invention is a program that causes a computer to implement the steps of the above method.

  This program may be provided as part of firmware incorporated in the device in order to perform basic control of hardware resources such as video and audio decoders. This firmware is stored in a semiconductor memory such as a ROM (Read Only Memory) or a flash memory in the device, for example. In order to provide the firmware or to update a part of the firmware, a computer-readable recording medium storing the program may be provided, and the program may be transmitted through a communication line.

  It should be noted that any combination of the above-described constituent elements and the expression of the present invention converted between a method, an apparatus, a system, a computer program, a data structure, a recording medium, and the like are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which improves the usability in the optical transmission type HMD which can change the transmittance | permeability of light can be provided.

It is a figure which shows typically an example of the external appearance of the three-dimensional image observation device which concerns on embodiment. It is a figure which shows typically the whole structure of the video presentation system which concerns on embodiment. It is a figure which shows typically the structure of the three-dimensional image observation device which concerns on embodiment. FIGS. 4A to 4B are diagrams illustrating the relationship between the lower limit value of the transmittance and the permitted setting range of the transmittance. It is a figure which shows an example of the message which the notification information generation part which concerns on embodiment produces | generates It is a state transition diagram of the stereoscopic image observation device according to the embodiment. It is a figure which shows another example of the message which the notification information generation part which concerns on embodiment produces | generates. It is a flowchart which shows the flow of the transmittance | permeability control processing by the stereoscopic image observation device which concerns on embodiment. It is a figure which shows typically the whole structure of the video presentation system which concerns on embodiment.

  FIG. 1 is a diagram schematically illustrating an example of the appearance of a stereoscopic video observation device 200 according to an embodiment. The stereoscopic video observation device 200 includes a presentation unit 202 that presents a stereoscopic video, a first imaging element 204, and a housing 206 that houses various modules. Although not shown, the stereoscopic video observation device 200 includes an earphone for outputting sound.

  The presentation unit 202 includes an optical transmissive HMD that presents a stereoscopic image to the user's eye, and a transmittance changing unit that changes the transmittance of external light that passes through the optical transmissive HMD. The transmittance changing unit also functions as a shutter by switching the light transmittance between 0% and 100%. The transmittance changing unit can be realized using a known technique such as a liquid crystal shutter or ECD (electrochromic display). The first image sensor 204 images a subject in an area including the field of view of the user wearing the stereoscopic video observation device 200. For this reason, the 1st image sensor 204 is installed so that it may be arrange | positioned around a user's eyebrows when the user wears the stereoscopic image observation device 200. The first image sensor 204 can be realized by using a known solid-state image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

  The housing 206 plays a role of a frame in the glasses-shaped stereoscopic image observation device 200 and accommodates various modules (not shown) used by the stereoscopic image observation device 200. The modules used by the stereoscopic image observation device 200 include an optical engine including a hologram light guide plate for realizing an optical transmission type HMD, a driver and a synchronization signal receiving unit for driving a transmittance changing unit, and other Wi-Fi ( A communication module such as a registered trademark module, an electronic compass, an acceleration sensor, a tilt sensor, a GPS (Global Positioning System) sensor, a 3G (3rd. Generation) module, and an illuminance sensor. These modules are examples, and the stereoscopic image observation device 200 does not necessarily need to be equipped with all of these modules. Which module is mounted may be determined according to the usage scene assumed by the stereoscopic video observation device 200.

  FIG. 1 is a diagram illustrating a glasses-type stereoscopic image observation device 200. The shape of the stereoscopic image observation device 200 may be various variations such as a hat shape, a belt shape that is fixed around the user's head, and a helmet shape that covers the entire user's head. Those skilled in the art will easily understand that the stereoscopic image observation device 200 having a shape is also included in the embodiment of the present invention.

  FIG. 2 is a diagram schematically illustrating the overall configuration of the video presentation system 100 according to the embodiment. The video presentation system 100 according to the embodiment includes a stereoscopic video observation device 200, a three-dimensional monitor 300, a second image sensor 302, and an information processing device 400.

  The three-dimensional monitor 300 displays a stereoscopic video by a frame sequential method. Since the left and right eyes of a human are about 6 cm apart, parallax occurs between the image seen from the left eye and the image seen from the right eye. The human brain is said to use parallax images perceived by the left and right eyes as one piece of information for recognizing depth. For this reason, when a parallax image perceived by the left eye and a parallax image perceived by the right eye are projected onto the respective eyes, it is recognized as a video having a depth by humans. The three-dimensional monitor 300 alternately displays the left-eye parallax image and the right-eye parallax image in a time-sharing manner. The three-dimensional monitor 300 can be realized using a known presentation device such as a liquid crystal television, a plasma display, or an organic EL monitor.

  As described above, the transmittance changing unit is a device having a variable light transmittance, and changes the amount of external light reaching the eyes of the user wearing the stereoscopic image observation device 200. Hereinafter, the description will be made on the assumption that the liquid crystal shutter 210 is employed as the transmittance changing unit. However, the transmittance changing unit is not limited to the liquid crystal shutter, and may be replaced by another technique if the light transmittance is variable. Those skilled in the art will understand what can be done.

  The liquid crystal shutter 210 opens and closes the left and right shutters in synchronization with the switching of the parallax image of the three-dimensional monitor 300. More specifically, when the left-eye parallax image is displayed on the 3D monitor 300, the right-eye shutter is closed and the left-eye shutter is opened, so that the user wearing the stereoscopic image observation device 200 can use the left-eye. Presents a parallax image. Conversely, when the three-dimensional monitor 300 displays a right-eye parallax image, the left-eye shutter is closed and the right-eye shutter is opened, and the right-eye parallax image is presented to the user.

  In order to realize this, the synchronization signal receiving unit 212 receives a synchronization signal for shutter switching. The synchronization signal is wirelessly transmitted from a signal transmission unit (not shown) provided in the three-dimensional monitor 300 or the information processing apparatus 400 using, for example, infrared light. The shutter control unit 220 controls opening and closing of the liquid crystal shutter 210 according to the synchronization signal received by the synchronization signal receiving unit 212.

  As described above, the presentation unit 202 includes the optically transmissive HMD 208 that presents a stereoscopic image to the user's eyes, and the liquid crystal shutter 210 that changes the transmittance of external light transmitted through the optically transmissive HMD 208.

  The video acquisition unit 226 acquires a virtual three-dimensional image to be presented to the user wearing the stereoscopic video observation device 200. The video acquisition unit 226 may acquire a video from outside via a communication module (not shown), or may be acquired by generating a video using a three-dimensional rendering technique. Here, when the video acquisition unit 226 acquires content including audio such as a movie or a game, the audio acquisition unit 222 acquires the audio. The sound acquired by the sound acquisition unit 222 is reproduced by the sound output unit 216. The audio output unit 216 can be realized by using an earphone (not shown) provided in the stereoscopic video observation device 200 or the like.

  The optically transmissive HMD 208 presents a user wearing the stereoscopic video observation device 200 with an image obtained by projecting the three-dimensional image acquired by the video acquisition unit 226 on the real space. FIG. 3 is a diagram illustrating an example of an image presented on the presentation unit 202 of the optically transmissive HMD 208 according to the embodiment. In the example shown in FIG. 3, a female person 250 and a male person 252 actually exist on the existing road 254. The images of the female person 250 and the male person 252 captured by the first image sensor 204 are analyzed by a person recognition engine (not shown) in the video acquisition unit 226. When the identification of the person is successful, the video acquisition unit 226 superimposes the balloon-type videos 256 and 258 on the female person 250 and the male person 252, respectively, and displays the person's face photo and name. The person recognition engine may be realized by using a known method such as a machine learning method.

  The video acquisition unit 226 may acquire the location and traveling direction of the user wearing the stereoscopic video observation device 200 from a GPS sensor (not shown), and display main facilities and the like in that direction. In the example shown in FIG. 3, a telop that displays the name of a station that exists in the direction of travel of the user is displayed over the real space image together with an arrow-shaped indicator 260. A simplified map 262 from the current position of the user to the destination is also displayed superimposed on the real space image. In addition, a mail reception telop 264 indicating that mail has been received from the mobile phone communication network via a 3G module (not shown) and an indicator 266 indicating the current external light transmittance (described later) are also displayed.

  As shown in FIG. 3, the presentation unit 202 of the optically transmissive HMD 208 displays a virtual image superimposed on a real space image. Therefore, for example, the brightness of the ambient light differs greatly between when the stereoscopic image observation device 200 is used outdoors in the daytime and when it is used at night or inside a building. As described above, in order to improve the visibility of the virtual image displayed to be superimposed on the image in the real space, the amount of external light transmitted through the presentation unit 202 is set according to the physical amount such as the brightness of the ambient light, for example. It is preferable to adjust.

  Therefore, the liquid crystal shutter 210 changes the transmittance of the external light transmitted to the optical transmission type HMD 208 under the control of the shutter control unit 220. Here, the “transmittance” is a ratio of light transmitted through the liquid crystal shutter 210, and is a value expressed as a percentage of the amount of light after passing through the liquid crystal shutter 210 when the amount of light before entering the liquid crystal shutter 210 is defined as 100. It is.

  Here, if the image presented on the presentation unit 202 of the optically transmissive HMD 208 is an image that does not include an image of the outside world, such as a movie image, for example, the lower the transmittance is set, that is, the more difficult it is to pass outside light. The higher the setting, the higher the visibility of the video. On the other hand, unlike the case where a normal stationary television monitor is used, the stereoscopic video observation device 200 is used in a state of being mounted on the user's head, so that the user can freely move around while observing the video. . Therefore, it is difficult for the user to move around freely in a setting that does not allow outside light to pass through, and usability is impaired. Therefore, the shutter control unit 220 also sets a lower limit value of the light transmittance that can be changed by the liquid crystal shutter 210. Here, “the lower limit value of the transmittance” set by the shutter control unit 220 is a lower limit value of the transmittance setting range permitted for the liquid crystal shutter 210.

  FIGS. 4A to 4B are diagrams illustrating the relationship between the lower limit value of the transmittance and the permitted setting range of the transmittance. FIG. 4A is a diagram showing a transmittance setting allowable range when the lower limit value of the transmittance is 20%, and FIG. 4B is a setting of transmittance when the lower limit value of the transmittance is 50%. It is a figure which shows the permission range.

As shown in FIG. 4A, when the shutter control unit 220 sets the lower limit value of the transmittance to 20%, the transmittance of the liquid crystal shutter 210 can be changed within the range of 20% to 100%. A setting lower than 20% which is the lower limit of the transmittance is prohibited. In FIG. 4A, the range where the setting of the transmittance is prohibited is indicated by hatching. When the lower limit value of the transmittance is set to 20%, at least 20% of the outside light passes through the liquid crystal shutter 210 and reaches the presentation unit 202, and a state in which the outside light is not transmitted is prevented. As described above, the shutter control unit 220 sets the lower limit value of the transmittance, so that it is possible to control the balance between the visibility of the video presented to the presentation unit 202 and the usability improvement by providing the external video. . Hereinafter, in the present specification, “lower limit of transmittance” may be referred to as “lower limit transmittance T _d ”.

  Returning to the description of FIG. The shutter control unit 220 sets a lower limit value of the transmittance based on the physical quantity detected by the detection unit 214. Therefore, the detection unit 214 includes an illuminance detection unit 230, a motion detection unit 232, a proximity detection unit 234, and a detection control unit 228 that comprehensively controls them.

  The illuminance detection unit 230 detects the illuminance around the stereoscopic image observation device 200. The shutter control unit 220 changes the lower limit value of the light transmittance based on the illuminance detected by the illuminance detection unit 230. Specifically, when the illuminance acquired by the illuminance detection unit 230 is high, the shutter control unit 220 sets the lower limit value of the transmittance smaller than when the illuminance is low. In the example illustrated in FIG. 4, FIG. 4A illustrates the transmittance setting permission range when the illuminance is high, and FIG. 4B illustrates the transmittance setting permission range when the illuminance is low. Thereby, for example, when the user uses the stereoscopic image observation device 200 outdoors in the daytime, it is permitted to set the transmittance low. This is because the brightness of ambient light is large in the outdoors in the daytime, and even if the transmittance is set low, the user can sufficiently observe the appearance of the outside world. On the other hand, since the brightness of the ambient light is small at night and inside the building, the lower amount of the transmittance is set to be high so as to secure the amount of external light that reaches the user's eyes.

  As described above, since the stereoscopic image observation device 200 is used in a state of being worn on the user's head, the user can freely move around. When the user uses the stereoscopic image observation device 200 while moving, it is preferable that the user can observe the external environment because the surrounding environment always changes. On the other hand, when viewing a content such as a movie in a stationary state at home or the like, the user may desire to completely block the outside image. As described above, it is preferable to change the settable transmittance range in accordance with the moving state of the stereoscopic image observation device 200.

  Therefore, the motion detection unit 232 acquires information regarding changes in the position coordinates of the stereoscopic video observation device 200 such as the speed and acceleration of the stereoscopic video observation device 200. The shutter control unit 220 changes the lower limit value of the light transmittance that can be changed by the liquid crystal shutter 210 based on the change in the position coordinates acquired by the motion detection unit 232. More specifically, when the change in the position coordinates acquired by the motion detection unit 232 is small, the shutter control unit 220 has a lower limit value of the light transmittance that the liquid crystal shutter 210 can change than when the change rate is large. Set to a smaller value. In the example shown in FIG. 4, FIG. 4A shows the transmission permission setting range when the position coordinate change is small, and FIG. 4B shows the transmission setting permission range when the position coordinate change is large. It is.

  Thereby, for example, when the user is moving at a high speed or when the acceleration is very large, it is possible to maintain a state in which the user can check the external environment. The shutter control unit 220 controls the lower limit setting of the transmittance based on the illuminance detected by the illuminance detection unit 230, and controls the lower limit setting of the transmittance based on the change of the position coordinates detected by the motion detection unit 232. May be performed simultaneously. For example, even when the user is moving at the same speed, when the ambient light illuminance is high, the shutter control unit 220 sets the lower limit value of the transmittance smaller than when the illuminance is low. Thereby, the lower limit value setting of the transmittance in consideration of both the illuminance of the ambient light and the moving speed of the user can be realized.

  Further, the shutter control unit 220 may set a priority order for the physical quantity used for controlling the lower limit value setting of the transmittance. For example, the shutter control unit 220 sets the lower limit value of the transmittance by giving priority to the information on the moving speed of the user over the information on the illuminance of the ambient light. Specifically, even when the ambient light illuminance is low, when the user is stationary, the shutter control unit 220 sets the lower limit value of the transmittance to 0%. Thereby, for example, the user can enjoy content such as a movie by turning off the light in the home and blocking the outside light.

  The proximity detection unit 234 in the detection unit 214 measures the distance between the stereoscopic image observation device 200 and a surrounding object or person. The shutter control unit 220 increases the lower limit value of the transmittance when the distance from the surroundings measured by the proximity detection unit 234 is equal to or less than a predetermined distance. Here, the “predetermined distance” is a reference distance for the shutter control unit 220 to determine whether or not the lower limit value of the transmittance is forcibly increased, and an assumed use scene of the stereoscopic image observation device 200. However, it is 2 meters, for example. Thereby, for example, it is possible to give a notice that an object is approaching to a user who is concentrated on the content reproduced by the stereoscopic image observation device 200. Therefore, the “predetermined distance” may be changed according to a change in position coordinates detected by the motion detection unit 232. Specifically, when the moving speed of the user is fast, the “predetermined distance” may be set longer than when the user is slow.

  As described above, the shutter control unit 220 automatically sets the lower limit value of the transmittance based on the physical quantity detected by the detection unit 214. For this reason, the lower limit value of the transmittance may be significantly changed while the user who uses the stereoscopic video observation device 200 does not intend. As a result, the transmittance actually set in the liquid crystal shutter 210 may also be greatly changed. For example, when the transmittance set for the liquid crystal shutter 210 is changed from 20% to 60%, the amount of light reaching the user's eyes increases three times, which may give the user a sense of discomfort. On the contrary, if the transmittance set in the liquid crystal shutter 210 is changed from 60% to 20%, the visibility of the outside world may be lowered.

  Therefore, the notification information generation unit 224, when the changeable light transmittance permitted to the liquid crystal shutter 210 by the shutter control unit is changed by a predetermined amount or more, prior to actually changing the transmittance setting, A message indicating that the transmittance is changed is generated and presented to the optically transmissive HMD 208. Here, the “predetermined amount of transmittance” is a reference change amount of the transmittance used to determine whether or not the notification information generation unit 224 generates a message that gives notice to the user. The “predetermined amount of transmittance” may be determined by experiment in consideration of a use scene assumed for the stereoscopic video observation device 200.

  FIG. 5 is a diagram illustrating an example of a message generated by the notification information generation unit 224 according to the embodiment. As shown in FIG. 5, in order to make it easier for the user to notice, information is superimposed on the scenery that the user is actually observing. Thereby, the user can be prepared to change the transmittance, and can reduce the unexpected feeling given to the user. Note that the notification information generation unit 224 may generate audio information as a message indicating that the transmittance is changed instead of or in addition to the video presented on the optical transmission type HMD 208. In this case, the sound generated by the notification information generation unit 224 is reproduced by the sound output unit 216 via the sound acquisition unit 222.

  As described above, the shutter control unit 220 automatically sets the lower limit value of the transmittance based on the physical quantity detected by the detection unit 214, but depending on the user, the lower limit value control of the transmittance by the shutter control unit 220 is stopped. It may be desired to do so. For example, this is a case where the stereoscopic image observation device 200 is used in an attraction venue or an amusement center.

  Therefore, the switching unit 218 sets whether or not the lower limit value control of the light transmittance that can be changed by the liquid crystal shutter 210 by the shutter control unit 220 is set. When the switching unit 218 prohibits the lower limit control of the light transmittance that can be changed by the liquid crystal shutter 210 by the shutter control unit 220, the stereoscopic image observation device 200 has an external light transmittance of 0%, that is, a non-transmissive state. Will be allowed.

  The switching unit 218 can be realized using a hardware switch (not shown) provided in the stereoscopic video observation device 200. Or you may implement | achieve using a software switch under control of the basic software which controls the operation | movement of the stereoscopic image observation device 200 centralizedly. In any case, depending on the setting of the switching unit 218, the stereoscopic image observation device 200 transitions between the non-transmission permitted state and the non-transmission prohibited state.

  FIG. 6 is a state transition diagram of the stereoscopic video observation device 200 according to the embodiment. As shown in FIG. 6, when the switching unit 218 permits the shutter control unit 220 to control the lower limit value of the light transmittance that can be changed by the liquid crystal shutter 210, the stereoscopic video observation device 200 enters the non-transmission permitted state ST1. When the stereoscopic video observation device 200 is in the non-transmission permitted state ST1, the stereoscopic video observation device 200 is switched when the switching unit 218 is switched to the light transmittance lower limit value control prohibition side that can be changed by the shutter control unit 220. Transits to the non-transparent prohibited state ST2. When the stereoscopic video observation device 200 is in the non-transmission prohibited state ST2, the switching unit 218 once again permits the lower limit control of the light transmittance that can be changed by the liquid crystal shutter 210 by the shutter control unit 220. 200 transitions to the non-transmission permitted state ST1.

  As described above, when the stereoscopic image observation device 200 is in the non-transmission permitted state ST1, external light may be completely blocked by the liquid crystal shutter 210. Therefore, when the state of the stereoscopic video observation device 200 is changed by the switching unit 218, the notification information generation unit 224 generates a message that notifies the user in advance and displays the message on the optical transmission type HMD 208. After the message generated by the notification information generation unit 224 is displayed on the optical transmission type HMD 208, the shutter control unit 220 performs the lower limit control of the transmittance according to the state of the stereoscopic image observation device 200.

  FIG. 7 is a diagram illustrating another example of a message generated by the notification information generation unit 224 according to the embodiment. As in the case shown in FIG. 5, in order to surely notice the user, information is superimposed on the scenery actually observed by the user. As a result, the user can be prepared to change the state of the stereoscopic video observation device 200, and can reduce the sense of surprise given to the user.

  FIG. 8 is a flowchart showing a flow of the transmittance control process by the stereoscopic video observation device 200 according to the embodiment. The processing in this flowchart starts when the power of the stereoscopic image observation device 200 is turned on, for example.

Shutter control unit 220, obtain the requested should set the transmittance T _a from an application or the like, or on the basis of the physical quantity detecting unit 214 detects, external light liquid crystal shutter 210 is transmitted through to an optical transmission type HMD the transmittance decides to change to _{T a} (S2). The shutter control unit 220 uses the switching unit 218 to check whether or not the state of the stereoscopic image observation device 200 is in the non-transmission permitted state. If stereoscopic video viewing device 200 is non-transmissive enabled state (S4 of Y), the shutter control unit 220 controls the liquid crystal shutter 210, setting the transmittance of the external light to be transmitted to an optical transmission HMD in T _a (S6).

If stereoscopic video viewing device 200 is non-transmissive disabled state (S4 of N), the shutter controller 220, the determined transmittance T _a investigate whether lower transmittance T _d or more. For _{T a} ≧ T _d (S8 of Y), the shutter control unit 220 controls the liquid crystal shutter 210, to set the transmittance of the external light to be transmitted to an optical transmission HMD to _{T a} (S6). When T _a <T _d (N in S8), the shutter control unit 220 controls the liquid crystal shutter 210 to set the transmittance of the external light transmitted to the optical transmission type HMD to the lower limit transmittance T _d (S10). ). When the shutter control unit 220 sets the transmittance of external light that is transmitted to the optically transmissive HMD, the processing in this flowchart ends.

  The case where the stereoscopic image observation device 200 according to the embodiment is mainly used alone has been described above. As described above, the liquid crystal shutter 210 of the stereoscopic image observation device 200 also functions as an optical shutter for observing a frame sequential three-dimensional monitor. Hereinafter, the case of observing a frame sequential three-dimensional monitor using the stereoscopic image observation device 200 according to the embodiment will be described.

  FIG. 9 is a diagram schematically showing the overall configuration of the video presentation system 100 according to the embodiment. The video presentation system 100 according to the embodiment includes a stereoscopic video observation device 200, a three-dimensional monitor 300, and an information processing apparatus 400.

  The three-dimensional monitor 300 displays a stereoscopic video by a frame sequential method. Since the left and right eyes of a human are about 6 cm apart, parallax occurs between the image seen from the left eye and the image seen from the right eye. The human brain is said to use parallax images perceived by the left and right eyes as one piece of information for recognizing depth. For this reason, when a parallax image perceived by the left eye and a parallax image perceived by the right eye are projected onto the respective eyes, it is recognized as a video having a depth by humans. The three-dimensional monitor 300 alternately displays the left-eye parallax image and the right-eye parallax image in a time-sharing manner. The three-dimensional monitor 300 can be realized using a known presentation device such as a liquid crystal television, a plasma display, or an organic EL monitor.

  The liquid crystal shutter 210 opens and closes the left and right shutters in synchronization with the switching of the parallax image of the three-dimensional monitor 300. More specifically, when the left-eye parallax image is displayed on the 3D monitor 300, the right-eye shutter is closed and the left-eye shutter is opened, so that the user wearing the stereoscopic image observation device 200 can use the left-eye. Presents a parallax image. Conversely, when the three-dimensional monitor 300 displays a right-eye parallax image, the left-eye shutter is closed and the right-eye shutter is opened, and the right-eye parallax image is presented to the user.

  In order to realize this, the synchronization signal receiving unit 212 receives a synchronization signal for shutter switching. The synchronization signal is wirelessly transmitted from a signal transmission unit (not shown) provided in the three-dimensional monitor 300 or the information processing apparatus 400 using, for example, infrared light. The shutter control unit 220 controls opening and closing of the liquid crystal shutter 210 according to the synchronization signal received by the synchronization signal receiving unit 212.

  As described above, the liquid crystal shutter 210 has two functions, that is, a function of changing the transmittance of light from the outside and a function as an optical shutter for observing a three-dimensional monitor of a frame sequential system. Therefore, as in the example shown in FIG. 9, when the 3D monitor 300 and the optically transmissive HMD 208 are simultaneously used to present a 3D video to the user, the shutter control unit 220 has the liquid crystal shutter 210 with the above-described two types. The operation of the liquid crystal shutter 210 is controlled so that the functions are realized simultaneously. Hereinafter, the control of the liquid crystal shutter 210 by the shutter control unit 220 in the case where the above two functions are realized simultaneously will be specifically described.

  The change in the transmittance of the liquid crystal shutter 210 is realized by using molecules called liquid crystals. The liquid crystal has a property that the polarization angle changes depending on the magnitude of the applied voltage. By controlling this voltage, the polarization angle of the liquid crystal molecules can be controlled, and the amount of light transmitted through the liquid crystal molecules can be controlled. There are two methods, the case where the transmittance is 100% when no voltage is applied to the liquid crystal molecules and the case where the transmittance is 0%. In any case, the voltage applied to the liquid crystal molecules is controlled. By doing so, the transmittance of the liquid crystal shutter 210 can be controlled from 0% to 100%. For example, if a voltage is applied so that the transmittance of the liquid crystal shutter 210 is 50%, the amount of light transmitted through the liquid crystal shutter 210 is naturally 50%. Hereinafter, for convenience of explanation, it is described that “the shutter of the liquid crystal shutter 210 is on” when the transmittance of the liquid crystal shutter 210 is 0%. When the transmittance of the liquid crystal shutter 210 is greater than 0%, it is described as “the shutter of the liquid crystal shutter 210 is off” regardless of the magnitude of the transmittance.

  The amount of light transmitted through the liquid crystal shutter 210 per unit time can also be controlled by opening and closing the liquid crystal shutter 210 at high speed, that is, by alternately changing the transmittance of the liquid crystal shutter 210 between 0% and 100%. it can. For example, when the transmittance of the liquid crystal shutter 210 is switched between 0% and 100% at a predetermined interval (for example, an interval of 1/120 seconds), the time during which light passes through the liquid crystal shutter 210 per unit time 100% The shielding time is equal. As a result, the amount of light transmitted through the liquid crystal shutter 210 per unit time is 50%.

Thus, the shutter control unit 220 sets the period T _ON when the shutter of the liquid crystal shutter 210 is on and the transmittance is 0%, the period T _OFF when the shutter is off, and the polarization angle of the liquid crystal when the shutter is off. Control the light transmittance M to change.

More specifically, the shutter control unit 220 sets the transmittance to be set as M, T _ON when the shutter of the liquid crystal shutter 210 is turned on, and T _OFF when the shutter is turned off. In this case, the magnitude of the voltage applied to the liquid crystal is controlled so that the light transmittance N satisfies the following formula (1), thereby controlling the polarization angle of the liquid crystal.
N = (T _ON + T _OFF ) / T _OFF × M (1)

For example, consider a case where the shutter control unit 220 sets the transmittance M of the liquid crystal shutter 210 to 30%. Here, it is assumed that the liquid crystal shutter 210 is repeatedly turned on for 1/60 seconds and turned off for 1/120 seconds. That is, T _ON = 1/60, T _OFF = 1/120, and M = 0.3. Substituting these values into equation (1) yields N = (1/60 + 1/120) / (1/120) × 0.3 = 0.9.

In this example, T _ON : T _OFF = 2: 1, and therefore the time during which light can pass through the liquid crystal shutter 210 is 1/3 in terms of unit time. Therefore, in order to set the transmittance M of the liquid crystal shutter 210 to 30% as a whole, the transmittance of light when the shutter is off must be set to 90%.

  Usage scenes of the stereoscopic image observation device 200 having the above configuration are as follows. When the user wears the stereoscopic image observation device 200 in the non-transmission prohibited state ST2 and observes the image presented on the optically transmissive HMD 208, the shutter control unit 220 follows the liquid crystal shutter 210 according to the physical quantity detected by the detection unit 214. Sets the lower limit of the amount of light that passes through. The shutter control unit 220 controls the operation of the liquid crystal shutter 210 according to the equation (1) so as to realize the transmittance actually set within a range not lower than the lower limit value of the transmittance set for the liquid crystal shutter 210. To do.

  As described above, according to the stereoscopic image observation device 200 according to the embodiment, it is possible to provide a technique for improving the usability in the optical transmission HMD capable of changing the light transmittance. In particular, by providing the non-transmission prohibited state in the optical transmission type HMD, it is possible to reduce the trouble given to the user due to a change request from an application, a malfunction of the transmittance control, or the like.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .

(First modification)
Although the case where the detection unit 214 includes the illuminance detection unit 230, the motion detection unit 232, and the proximity detection unit 234 has been described above, the sensors mounted on the detection unit 214 are not limited to these. In addition to this, for example, various sensors such as a temperature sensor, a volume sensor, and a humidity sensor may be mounted according to the usage scene of the stereoscopic image observation device 200.

(Second modification)
In the above description, it has been described that the switching unit 218 can switch between the non-transmission permitted state and the non-transmission prohibited state of the stereoscopic image observation device 200. However, when the stereoscopic image observation device 200 is shipped, the non-transmission prohibited state is set. It is preferable. Accordingly, it is possible to reduce the confusion that can be given to the user who uses the stereoscopic image observation device 200 for the first time due to the transmittance control.

  DESCRIPTION OF SYMBOLS 100 image | video presentation system, 200 stereoscopic image observation device, 202 presentation part, 204 1st image sensor, 206 housing | casing, 208 optical transmission type HMD, 210 liquid crystal shutter, 212 synchronization signal receiving part, 214 detection part, 216 audio | voice output part, 218 switching unit, 220 shutter control unit, 222 audio acquisition unit, 224 notification information generation unit, 226 video acquisition unit, 228 detection control unit, 230 illuminance detection unit, 232 motion detection unit, 234 proximity detection unit, 264 mail reception telop 300 Three-dimensional monitor, 400 Information processing device.

Claims (4)

An optically transmissive HMD that presents an image observed when a virtual image is projected in real space;
A transmittance changing unit that changes the transmittance of light transmitted through the optical transmission type HMD;
An image observation device comprising: a shutter control unit that sets a lower limit value of light transmittance that can be changed by the transmittance changing unit. Obtaining a change in position coordinates of an optically transmissive HMD that presents an image observed when a virtual image is projected in real space;
Controlling a transmittance changing unit provided in the optical transmission type HMD based on the obtained change in position coordinates, and setting a lower limit value of the transmittance of the light transmitted through the optical transmission type HMD; A transmission control method characterized by being executed by a processor. An optically transmissive HMD that presents an image observed when a virtual image is projected in real space;
A transmittance changing unit that changes the transmittance of light transmitted through the optical transmission type HMD;
A control unit for setting the transmittance of light that can be changed by the transmittance changing unit;
An image observation device comprising: a switching unit configured to set whether or not the transmittance changing unit can change the transmittance of light that can be changed by the control unit. Presenting an image observed when a virtual image is projected in real space to an optically transmissive HMD;
Changing the transmittance of light transmitted through the optically transmissive HMD;
And a step of setting whether or not to change the transmittance of light transmitted through the optically transmissive HMD.

Images