Patent Publication Number: US-11662831-B2

Title: Image display apparatus and image display method

Description:
TECHNICAL FIELD 
     The present invention relates to an image display apparatus and an image display method. 
     BACKGROUND ART 
     In order to support work in factory work and equipment maintenance work, a head mounted image display apparatus has been utilized. In many cases, a worker is holding an article necessary for objective work, and it is required that an input method to the image display apparatus is simple. As a simple input method, input means by a voice operation or a gesture operation has been devised. 
     In order to realize the gesture operation, it is necessary to recognize a target object to be gestured, and to further recognize a motion of the target object. In order to recognize a target object and a motion thereof, a three-dimensional recognition technique using a range image is utilized. For example, as Patent Document 1, a method of measuring a distance between an image display unit and a target object by using a TOF (Time Of Flight) sensor to realize gesture recognition has been devised. 
     RELATED ART DOCUMENTS 
     Patent Documents 
     
         
         Patent document 1: Japanese Patent Application Publication No. 2015-213212 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     As a method of obtaining a range image for recognizing gesture, there are cited a method of using a TOF sensor as described in Patent Document 1 described above, a method of using an active TOF type or Structured Light type three-dimensional distance measuring sensor, and a passive type method by a stereo camera type. However, each of the methods has a problem that a head mounted image display apparatus becomes large and is expensive in order to install it in the head mounted image display apparatus. As a result, a size of the image display apparatus is increased, and this becomes a load on a user thereof. 
     Further, as described above, in order to optimize a visual field area, usage of a wide angle lens or a fisheye lens, or optimization of a method of installing a distance measuring sensor may be cited. However, these also become factors that increase the size of the apparatus. As a result, a user who wears the apparatus imposes a burden. 
     It is an object of the present invention to provide an image display apparatus and a display method capable of reducing a load on a user when the user wears the apparatus. 
     The foregoing and other objects, and new features of the present invention will become more apparent from the detailed description of the present specification and the appending drawings. 
     Means for Solving the Problem 
     An outline of representative invention of the present invention disclosed in the present application will briefly be explained as follows. 
     According to a representative embodiment of the present invention, there is provided an image display apparatus capable of being mounted on a head of a user. The image display apparatus includes: an image sensor configured to convert an optical image into an image signal and output the converted image signal, the optical image being captured by a plurality of light receiving elements arranged in an array on an imaging surface; a modulator provided on a light receiving surface of the image sensor, the modulator having a first pattern that includes a plurality of patterns different from each other, the modulator being configured to modulate intensity of light; a gesture detecting unit configured to divide image data obtained by receiving light transmitted through the modulator by the image sensor in accordance with the plurality of patterns included in the first pattern, the gesture detecting unit being configured to restore an image by calculation based on a second pattern corresponding to the first pattern, the gesture detecting unit being configured to obtain an image for detecting gesture of the user; a gesture recognizing unit configured to specify the gesture of the user by using the image obtained by the gesture detecting unit, the gesture recognizing unit being configured to recognize an instruction corresponding to the specified gesture; and an image display unit configured to display a result based on the instruction recognized by the gesture recognizing unit. 
     Effects of the Invention 
     Effects obtained by the representative invention of the present invention disclosed in the present application will briefly be explained as follows. 
     Namely, according to the representative embodiment of the present invention, it is possible to reduce a load on a user when the user wears the apparatus. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG.  1    is a view illustrating an outline of an image display apparatus according to a first embodiment; 
         FIG.  2    is a view illustrating a functional configuration of the image display apparatus according to the first embodiment; 
         FIG.  3    is a view illustrating a processing flow by an example of the image display apparatus; 
         FIG.  4    is a view illustrating an example of a basic imaging apparatus using a distance measuring sensor; 
         FIG.  5    is a view illustrating an imaging unit in the basic imaging apparatus using the distance measuring sensor; 
         FIG.  6    is a view illustrating an imaging unit in the basic imaging apparatus using the distance measuring sensor; 
         FIG.  7    is a view illustrating an example of a photographing pattern or a developing pattern; 
         FIG.  8    is a view illustrating another example of the photographing pattern or the developing pattern; 
         FIG.  9    is a view for explaining that a projection image from a pattern substrate surface to an image sensor by oblique incidence parallel light generates in-plane shift; 
         FIG.  10    is a view illustrating a projection image of an embodiment of a photographing pattern; 
         FIG.  11    is a view illustrating an embodiment of a developing pattern; 
         FIG.  12    is a view illustrating an embodiment of a development image by a correlation developing method; 
         FIG.  13    is a view illustrating an embodiment of a moire fringe by a moire developing method; 
         FIG.  14    is a view illustrating an embodiment of the development image by the moire developing method; 
         FIG.  15    is a view illustrating an embodiment of a combination of initial phases in fringe scanning; 
         FIG.  16    is a view illustrating an embodiment of a photographing pattern; 
         FIG.  17    is a view illustrating a processing flow of an embodiment of an image processing unit by the correlation developing method; 
         FIG.  18    is a view illustrating a processing flow of an embodiment of the image processing unit by the moire developing method; 
         FIG.  19    is a view illustrating that a photographing pattern is projected in a case where an object is positioned at an infinite distance; 
         FIG.  20    is a view illustrating that a photographing pattern is enlarged in a case where an object is positioned at a finite distance; 
         FIG.  21    is a view illustrating an embodiment of a gesture detecting unit in the image display apparatus; 
         FIG.  22    is a view illustrating an embodiment of a distance measuring sensor unit; 
         FIG.  23    is a view illustrating another embodiment of the distance measuring sensor unit; 
         FIG.  24    is a view illustrating a schematic view of the image display apparatus; 
         FIG.  25    is a view illustrating a schematic view of the image display apparatus; 
         FIG.  26    is a view illustrating a schematic view of a positional relationship between an image sensor and a modulator in a distance measuring sensor unit; 
         FIG.  27    is a view illustrating an embodiment of a positional relationship between an image sensor and a modulator in a distance measuring sensor unit; 
         FIG.  28    is a view illustrating a pattern center of the modulator; 
         FIG.  29    is a view illustrating an embodiment of the modulator; 
         FIG.  30    is a view illustrating another embodiment of the modulator; 
         FIG.  31    is a view illustrating a functional configuration of an image display apparatus according to a third embodiment; 
         FIG.  32    is a view illustrating a processing flow according to the third embodiment; 
         FIG.  33    is a view illustrating an embodiment in which a position of a modulator is changed dynamically; 
         FIG.  34    is a view illustrating another embodiment in which the position of the modulator is changed dynamically; 
         FIG.  35    is a view illustrating a schematic view of a structure of an image sensor; 
         FIG.  36    is a view illustrating an embodiment of a liquid crystal display pattern; 
         FIG.  37    is a view illustrating an embodiment of an effective pattern of the modulator; 
         FIG.  38    is a view illustrating a relationship between a structure and an optical axis of an image sensor; 
         FIG.  39    is a view illustrating the relationship between the structure and the optical axis of the image sensor; 
         FIG.  40    is a view illustrating the relationship between the structure and the optical axis of the image sensor; 
         FIG.  41    is a view illustrating the relationship between the structure and the optical axis of the image sensor; 
         FIG.  42    is a view illustrating a visual field based on a relationship between the image sensor and photographing pattern; 
         FIG.  43    is a view illustrating the structure of the image sensor according to the embodiment; 
         FIG.  44    is a view illustrating the relationship between the structure and the optical axis of the image sensor according to the embodiment; 
         FIG.  45    is a view illustrating the structure of the image sensor according to the embodiment; and 
         FIG.  46    is a view illustrating a schematic view of ahead mounted image display apparatus according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that Further, the same components are in principle denoted by the same reference numeral throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. On the other hand, a component that has been explained in a certain drawing by applying a reference numeral thereto is not illustrated again when another drawing is to be explained, but the component may be referred to by applying the same reference numeral thereto. 
     First Embodiment 
       FIG.  1    is a view illustrating an outline of an image display apparatus according to a first embodiment. An image display apparatus  101 A according to an embodiment of the present invention is an eyeglass type image display apparatus (that is, an image display apparatus that can be mounted or worn on a head of a user), and is an apparatus that displays an image in portions corresponding to positions of lenses in so called eyeglasses. The image display apparatus  101 A includes a distance measuring sensor unit  102 , image display units  103 , and a light source unit  104 . The image display apparatus  101 A is an example in which an image display function and a calculation processing function are integrated with an image display apparatus  101  to be worn or mounted on a head. 
     The image display apparatus  101 A displays information (for example, an image or the like) in the image display units  103  positioned at the portions corresponding to the lens portions of the eyeglasses. Further, the image display apparatus  101 A specifies gesture of the user by means of the distance measuring sensor unit  102  and the like; recognizes an operation (or an instruction) corresponding to the specified gesture; and changes the content to be displayed in the image display units  103  in accordance with the recognized operation. As illustrated in  FIG.  1   , the image display apparatus  101 A is an eyeglass type apparatus, but is not limited to this. The image display apparatus  101 A may have a shape by which the image display apparatus  101 A can be mounted on the head. 
     Further, the image display units  103  described above may not be provided at positions corresponding to both eyes, and may be provided at a position corresponding to one eye. Further, the distance measuring sensor unit  102  may not be provided at a center portion of the image display apparatus  101 , but may be provided at an end portion of the image display apparatus  101 , for example. In this case, compared with a case where the distance measuring sensor unit  102  is installed at the center, it is possible to improve designability because the distance measuring sensor unit  102  becomes less noticeable. 
     Further, the light source unit  104  is set in advance so as to be capable of irradiating an area beyond a distance measuring range of the distance measuring sensor unit  102 . For example, in a case where an irradiation range of one light source is narrow, a plurality of light sources is provided. For example, the light source units  104  may be respectively provided at both sides of the image display apparatus  101 . This makes it possible to widen the irradiation range. 
     Subsequently, functions of the image display apparatus  101  according to the first embodiment will be described with reference to  FIG.  2   .  FIG.  2    is a view illustrating a functional configuration of the image display apparatus  101 A according to the first embodiment. As illustrated in  FIG.  2   , the image display apparatus  101 A includes the distance measuring sensor unit  102 , the image display unit  103 , the light source unit  104 , an entire control unit  203 , a light source control unit  204 , a gesture detecting unit  206 , an image dividing unit  208 , an image processing unit  209 , a distance measurement processing unit  210 , a gesture recognizing unit  213 , an image display control unit  214 , a camera control unit  216 , and a camera unit  217 . 
     The distance measuring sensor unit  102  is a part for imaging a photographic subject. Details thereof will be described later. The image display unit  103  is a part for displaying an image, and is a display device or the like. The light source unit  104  is a part for irradiating light. For example, the light source unit  104  irradiates near infrared light. 
     The entire control unit  203  is a central processing unit, and is a portion that executes the whole control in the image display apparatus  101 A. The entire control unit  203  is realized by a CPU (Central Processing Unit) or the like, for example. 
     The light source control unit  204  is a part for controlling the light source unit  104 , and operates the light source unit  104  at predetermined intervals. The light source control unit  204  is realized by a CPU or the like. 
     The gesture detecting unit  206  is a part of controlling the distance measuring sensor unit  102  to obtain an image for detecting gesture on the basis of image data obtained by the distance measuring sensor unit  102 . The gesture detecting unit  206  is realized by a GPU (Graphics Processing Unit) or the like. The gesture detecting unit  206  has the image dividing unit  208 , the image processing unit  209 , and the distance measurement processing unit  210 . When the image for detecting gesture is obtained, the gesture detecting unit  206  transmits the image to the gesture recognizing unit  213 . Details of the gesture detecting unit  206  will be described later. 
     The gesture recognizing unit  213  is a part for recognizing gesture on the basis of the image detected by the gesture detecting unit  206 , and executing a process based on the gesture. The gesture recognizing unit  213  is realized by a CPU or the like. When the image for detecting gesture is obtained from the gesture detecting unit  206 , the gesture recognizing unit  213  analyzes the obtained image, specifies gesture of a target object (for example, a hand of the user), and recognizes an instruction corresponding to the specified gesture, thereby recognizing the gesture. The gesture recognizing unit  213  in advance stores information in which gesture and meaning of the gesture are associated with each other, and recognizes the instruction indicated by the specified gesture. 
     When the gesture is recognized, the gesture recognizing unit  213  transmits an instruction signal to the image display control unit  214  on the basis of the meaning of the gesture. 
     The image display control unit  214  is a part for controlling the image display unit  103 . The image display control unit  214  receives the instruction signal from the gesture recognizing unit  213  or the like, and causes the image display unit  103  to display an image on the basis of the instruction signal. In a case where an instruction signal indicating enlargement of the image displayed by the image display unit  103  is received, for example, the image display control unit  214  enlarges and displays the displaying image. 
     The camera control unit  216  is a part for controlling the camera unit  217 . When an instruction signal by the entire control unit  203  or the like is received, the camera control unit  216  operates the camera unit  217 . Further, when an image is obtained from the camera unit  217  as a result that the camera unit  217  is operated, the camera control unit  216  transmits the image to the image display control unit  214 . 
     The camera unit  217  is an imaging means, and is a part configured to take a still image or a moving image of an outside world. The camera unit  217  photographs the outside world in response to an instruction signal by the camera control unit  216 , and transmits a photographed result to the camera control unit  216 . 
     Subsequently, a processing procedure by the image display apparatus  101  will be described with respect to  FIG.  3   .  FIG.  3    is a flowchart illustrating a procedure to recognize gesture of a user by the image display apparatus  101 A and execute processes based on the recognized gesture. The entire control unit  203  executes the whole control of processes illustrated in  FIG.  3   . 
     First, at predetermined timing, the light source control unit  204  controls the light source unit  104  to adjust an amount of light to be irradiated and irradiate light (Step S 1 ). Subsequently, the gesture detecting unit  206  obtains an image for detecting gesture on the basis of image data obtained by the distance measuring sensor unit  102  (Step S 2 ). The gesture recognizing unit  213  recognizes gesture on the basis of the image obtained by the gesture detecting unit  206  (Step S 3 ). The image display control unit  214  executes a display control in response to an instruction signal based on a recognition result by the gesture recognizing unit  213  (Step S 4 ), and terminates the processing. 
     Subsequently, before details of configurations of the gesture detecting unit  206  and the distance measuring sensor unit  102  will be described, basic principle of imaging and distance measuring by using the distance measuring sensor unit  102  will be described. 
     &lt;Photographing Principle of Infinite Object&gt; 
       FIG.  4    is an explanatory drawing illustrating one example of a basic configuration of an imaging apparatus using the distance measuring sensor unit  102  according to the present embodiment. The distance measuring sensor unit  102  is configured to obtain an image of an object in an outside world without using a lens that forms an image. As illustrated in  FIG.  4   , the distance measuring sensor unit  102  is configured to calculate an image obtained by the distance measuring sensor unit  102  by using the gesture detecting unit  206 . 
     A structure of the distance measuring sensor unit  102  will be described with reference to  FIG.  5   .  FIG.  5    is a view illustrating a configuration example of the distance measuring sensor unit  102 . The distance measuring sensor unit  102  is constructed by an image sensor  803 , a pattern substrate  804 , a photographing pattern  805  (first pattern). The pattern substrate  804  is fixed so as to adhere tightly to a light receiving surface of the image sensor  803 , and is configured so that the photographing pattern  805  is formed on the pattern substrate  804 . 
     The pattern substrate  804  is made of transparent material, such as glass or plastic, with respect to visible light, for example. The photographing pattern  805  is formed by depositing metal such as aluminum or chromium by a sputtering method used for a semiconductor process, for example. A pattern can be shaded by a pattern in which aluminum is deposited and a pattern in which aluminum is not deposited. 
     Note that formation of the photographing pattern  805  is not limited to this. For example, the pattern may be formed by shading by means of printing of an ink jet printer. The pattern may be formed by any means so long as modulation of a transmission factor can be realized. Further, the visible light has been described herein as an example. For example, when photographing by far infrared ray is executed, material transparent to the far infrared ray, such as germanium, silicon, or chalcogenide, that is, material transparent to a wavelength that becomes a photographing target may be used for the pattern substrate  804 , for example, and material that blocks the far infrared ray may be used for the photographing pattern  805 . 
     Note that the method of forming the photographing pattern  805  on the pattern substrate  804  has been mentioned herein, but as illustrated in  FIG.  6   , it can also be realized by forming the photographing pattern  805  as a thin film, and holding the photographing pattern  805  by supporting members  801 . Note that in this apparatus, a photographing field angle can be changed by a thickness of the pattern substrate  804 . Therefore, for example, when the pattern substrate  804  is configured as illustrated in  FIG.  6    and has a function to be capable of changing a length of each of the supporting members  801 , it is possible to execute photographing while changing a field angle during the photographing. 
     Returning to  FIG.  5   , pixels  803   a  that are light receiving elements are regularly arranged on a surface of the image sensor  803  in a grid-like (or array) manner. This image sensor  803  converts a light image received by the pixels  803   a  into an image signal that is an electric signal. The image signal outputted from the image sensor  803  is subjected to image processing by the gesture detecting unit  206 , and is outputted to the gesture recognizing unit  213 . Thus, the image sensor  803  converts optical images respectively captured by a plurality of light receiving elements arranged in an array on an imaging surface into image signals, and outputs the converted image signals. 
     In a case where it is photographed by the above configuration, intensity of light of light for transmitting the photographing pattern  805  is modulated by the photographing pattern  805 , the transmitted light is received by the image sensor  803 . The image signal outputted from the image sensor  803  is subjected to image processing by the image processing unit  209  included in the gesture detecting unit  206 , and is outputted to the gesture recognizing unit  213 . 
     Subsequently, a photographing principle in the distance measuring sensor unit  102  will be described. First, the photographing pattern  805  is a concentric circle-shaped pattern in which pitches fine down so as to be inversely proportional to radii from a center thereof, and is defined as l(r)=1+cos βr 2  (Formula (1)) by using a radius r from a reference coordinate that is a center of the concentric circles and a coefficient β. A transmission factor of the photographing pattern  805  is modulated so as to be proportional to this formula. 
     A plate with such fringes is called as a Gabor zone plate or a Fresnel zone plate.  FIG.  7    illustrates an example of the Gabor zone plate by Formula (1), and  FIG.  8    illustrates an example of the Fresnel zone plate by binarizing Formula (1) by a threshold value 1. Note that, hereinafter, only an x axis direction will be described by formulas for simplification, but it is possible to two-dimensionally develop and consider the plate by considering a y axis direction in the similar manner. 
     It is assumed that as illustrated in  FIG.  9   , parallel light enters the pattern substrate  804 , on which the photographing pattern  805  is formed, with a thickness d at an angle θ 0  with respect to the y axis direction. By defining a refracting angle in the pattern substrate  804  as θ, light multiplied by a transmission factor of a surface grid geometrical-optically enters the image sensor  803  while being shifted by k=d×tan θ. At this time, a projection image with intensity distribution like I p (x)=1+cos[β(x+k) 2 +ϕ] (Formula (2)) is detected on the image sensor  803 . Note that (indicates an initial phase of transmission factor distribution in Formula (1).  FIG.  10    illustrates an example of the projection image of this photographing pattern  805 . The image is shifted by k as Formula (2) and is projected. This becomes an output of the distance measuring sensor unit  102 . 
     Next, development processing by a correlation developing method and a moire developing method of the image processing unit  209  will be described. 
     In the correlation developing method, the image processing unit  209  calculates a cross correlation function between the projection image of the photographing pattern  805  ( FIG.  10   ) and a developing pattern  1501  ( FIG.  11   ) that is a second pattern, thereby obtaining a bright spot with a shift amount k ( FIG.  12   ). Note that when the cross correlation calculation is executed by two-dimensional convolution calculation, a calculation amount generally becomes larger. Thus, a principle of an example of calculation using Fourier transform will be described using formulas. First, the developing pattern  1501  uses the Gabor zone plate or the Fresnel zone plate in the similar manner to the photographing pattern  805 . Thus, by using an initial phase Φ, the developing pattern  1501  is expressed as I B (x)=cos(βx 2 |Φ) Formula (3). Since the developing pattern  1501  is used in the image processing, it is not necessary to be offset by “one” as Formula (1), and there is no problem even if it has a negative value. 
     Fourier transforms of Formulas (1) and (3) are respectively as follows: 
     
       
         
           
             
               
                 
                   
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     Here, F indicates calculation of Fourier transform, u is a frequency coordinate in an x direction, and δ with parentheses is a delta function. What is important in this formula is that the formula after Fourier transform also becomes the Fresnel zone plate or the Gabor zone plate. Therefore, the image processing unit  209  may directly generate a developing pattern after Fourier transform on the basis of this formula. This makes it possible to reduce a calculation amount. Next, by multiplying Formulas (4) and (5), it becomes 
                 ℱ   [       I   F     (   x   )     ]     ·     ℱ   [       I   B     (   x   )     ]       =         1     2   ⁢       π   ⁢   β           ⁢   sin   ⁢     (       π     4           -   Φ     )     ⁢     δ   ⁡   (   u   )       +         e       -   i     ⁢   k   ⁢   u         8   ⁢   π   ⁢   β       ·     [       sin   2     (         u   2       4   ⁢   β       -   Φ   +     π   4       )     ]               
(Formula (6)). The term exp(−iku) expressed by this exponential function is a signal component, and this term is subjected to Fourier transform to be converted as    −1  [e −iku ]=2πδ(x+k) (Formula (7)). It is possible to obtain a bright spot at a position of k on the original x axis. This bright spot indicates a light flux at infinite, and is no other than a photographing image by the distance measuring sensor unit  102  illustrated in  FIG.  5   .
 
     Note that the correlation developing method may be realized by a pattern that is not limited to the Fresnel zone plate or the Gabor zone plate, for example, a random pattern so long as an autocorrelation function of the pattern has a single peak. 
     Next, in the moire developing method, the image processing unit  209  generates moire fringes ( FIG.  13   ) by multiplying the projection image of the photographing pattern  805  ( FIG.  10   ) and the developing pattern  1501  ( FIG.  11   ), and obtains bright spots with a shift amount kβ/n ( FIG.  14   ) by Fourier transform. When this moire fringe is indicated by a formula, it becomes
 
 I   F ( x )· I   B ( x )={1+cos[β( x+k ) 2 +Φ]}cos(β x   2 +Φ)=½[2 cos(β x   2 +Φ)+cos(2β x   2 +2 kβx+ 2β k   2 +2Φ)+cos(2 kβx+βk   2 )]
 
(Formula (8)). It can be seen that a third term of this expansion is a signal component and an area in which straight, equally spaced interval patterns are overlapped in the direction of shift of the two patterns. A fringe generated at relatively low spatial frequency due to such overlap of such fringes is called as a moire fringe. Two-dimensional Fourier transform of this third term becomes
 
                     ℱ   [     cos   ⁢   2   ⁢   k   ⁢   β   ⁢   x     ]     =       δ   ⁡   (     u   +       k   ⁢   β     π       )     +       δ   ⁡   (     u   -       k   ⁢   β     π       )     .               (     Formula   ⁢           (   9   )       )               
Here, F indicates calculation of Fourier transform, u is a frequency coordinate in the x direction, and δ with parentheses is a delta function. It can be seen from this result that a peak of spatial frequency occurs at a position of u=±kβ/π in a spatial frequency spectrum of the moire fringe. This bright spot indicates a light flux at infinite, and is no other than a photographing image by the distance measuring sensor unit  102  illustrated in  FIG.  5   . Thus, the image processing unit  209  restores an image by calculation based on the second pattern.
 
     &lt;Noise Cancellation&gt; 
     Although a signal component is focused in conversion from Formula (6) to Formula (7) and conversion from Formula (8) to Formula (9), terms other than the signal component actually impede the development. Therefore, the image processing unit  209  executes noise cancellation based on fringe scanning. By using orthogonality of a trigonometric function, when a multiplication result of Formula (6) is integrated with respect to Φ as 
                       ∫   0     2   ⁢   π             ℱ   [       I   F     (   x   )     ]     ·     ℱ   [       I   B     (   x   )     ]       ⁢   d   ⁢   Φ       =       1     4   ⁢   β       ⁢     e       -   i     ⁢   k   ⁢   u                 (     Formula   ⁢           (   10   )       )               
in the correlation developing method, a noise term is cancelled and a constant multiple of the signal term remains. Similarly, when a multiply result of Formula (8) is integrated with respect to Φ as ∫ 0   2π I F (x)·I S (x)aΦ=π cos(2kβx+βk 2 ) (Formula (11)) in the moire developing method, a noise term is cancelled and a constant multiple of the signal term remains.
 
     Note that each of Formulas (10) and (11) is indicated by an integral form, but it is also possible to obtain the similar effect actually by calculating the toral sum of a combination of (as illustrated in  FIG.  15   . Like this combination, (may be set so that an angle between 0 and 2π is equally divided. 
     In the fringe scanning that has been explained above, it is necessary to use a plurality of patterns each having a different initial phase as the photographing pattern  805 . In order to realize this, for example, there is a method of switching patterns by space division. 
     In order to realize space division fringe scanning, as illustrated in  FIG.  16   , the image processing unit  209  executes processing by using the photographing pattern  805  with a plurality of initial phases. After one image is obtained, the image processing unit  209  divides the one image into four in accordance with each initial phase pattern in the image processing unit  209 , and executes fringe scanning calculation. 
     Subsequently, an outline of the image processing by the image processing unit  209  based on an imaging principle described above will be described. 
       FIG.  17    is a flowchart illustrating an outline in a case where the image processing unit  209  uses the correlation developing method. First, the image processing unit  209  obtains a plurality of sensor images outputted from the image sensor  803  by the space division fringe scanning, and executes two-dimensional Fast Fourier transform (FFT: Fast Fourier Transform) calculation for each of the sensor images (Step S 11 ). Next, the image processing unit  209  generates a developing pattern  1501  to be used for the development processing by executing developing pattern FFT calculation (Step S 12 ). Subsequently, the image processing unit  209  executes fringe scanning calculation on the basis of Formula (10) (Step S 13 ), and executes inverse two-dimensional FFT calculation (Step S 14 ). 
     Since this calculation result becomes a complex number, the image processing unit  209  executes a real number converting process in which an absolute value or a real part is taken to convert an image of a photographing target into a real number and develop it (Step S 15 ). The image processing unit  209  then executes, with respect to the obtained image, contrast enhancement processing (Step S 16 ) and color balance adjustment (Step S 17 ), and outputs it as a photographing image. As described above, the image processing by the image processing unit  209  is terminated. 
     On the other hand,  FIG.  18    is a flowchart illustrating an outline in a case where the image processing unit  209  uses the moire developing method. First, the image processing unit  209  obtains a plurality of sensor images outputted from the image sensor  803  by the space division fringe scanning. Subsequently, the image processing unit  209  generates a developing pattern  1501  to be used for the development processing (Step S 21 ), and executes fringe scanning calculation for each of the sensor images on the basis of Formula (11) (Step S 22 ). The image processing unit  209  obtains a frequency spectrum by executing two-dimensional FFT calculation for this (Step S 23 ), and executes spectrum segmenting for segmenting data on a necessary frequency area of this frequency spectrum (Step S 24 ). The following processes (that is, processes at Step S 25  to Step S 27 ) are respectively similar to the processes at Steps S 15  to S 17  in  FIG.  17   . 
     &lt;Photographing Principle of Finite Distance Object&gt; 
     Next,  FIG.  19    illustrates a state of projection of the photographing pattern  805  to the image sensor  803  in a case where a photographic subject is distant as mentioned above. A spherical wave from a point  2301  that constitutes a distant object becomes a plane wave while propagating a sufficient long distance, and irradiates the photographing pattern  805 . In a case where a projection image  2302  thereof is projected to the image sensor  803 , the projection image has substantially the same shape as the photographing pattern  805 . As a result, it is possible to obtain a single bright spot by executing the development processing for the projection image  2302  using a developing pattern. 
     On the other hand, imaging of an object with a finite distance will be described.  FIG.  20    is an explanatory drawing illustrating that projection of the photographing pattern  805  to the image sensor  803  is enlarged by the photographing pattern  805  in a case where an object to be imaged is at a finite distance. 
     In a case where a spherical wave from a point  2401  that constitutes an object irradiates the photographing pattern  805  and a projection image  2402  is projected to the image sensor  803 , the projection image is enlarged substantially evenly. Note that the gesture detecting unit  206  can calculate this magnification ratio α as 
                   α   =       f   +   d     f             (   12   )               
by using a distance f between the photographing pattern  805  and the point  2401 .
 
     Therefore, if a developing pattern designed for parallel light is used as it is to execute development processing, it is impossible to obtain a single bright spot. Therefore, in a case where the developing pattern  1501  is enlarged in accordance with the evenly enlarged projection image of the photographing pattern  805 , a single bright spot can be obtained again for the enlarged projection image  2402 . For this reason, it is possible to correct a coefficient β of the developing pattern  1501  by setting β/α 2 . 
     This makes it possible to selectively reproduce light from the point  2301  positioned at a distance that is not necessarily infinite. Therefore, it is possible to photograph the pattern by focusing on an arbitrary position. In other words, it is possible to calculate a distance to the arbitrary position. The present principle allows distance measurement as a distance measuring sensor. 
     In view of the principle described above, a configuration of the gesture detecting unit  206  according to the present embodiment will be described.  FIG.  21    illustrates configurations of the distance measuring sensor unit  102  and the gesture detecting unit  206 . The distance measuring sensor unit  102  includes a modulator  2502  and an image sensor  803 . The modulator  2502  is configured from the pattern substrate  804  and the photographing pattern  805 , which are illustrated in  FIG.  5   , for example. 
     Patterns of the modulator  2502  (the photographing pattern  805 ) are configured to two-dimensionally arrange a plurality of initial phase patterns like patterns when the initial phases Φ of  FIG.  16    are respectively {0, π/2, π, and 3π/2}, for example. Namely, the photographing pattern  805  includes a plurality of patterns that are different from each other. The image dividing unit  208  divides an output of the image sensor  803  into areas based on the respective patterns of the modulator  2502 , and in turn transmits them to the image processing unit  209  of the gesture detecting unit  206 . Thus, the image dividing unit  208  of the gesture detecting unit  206  divides the image data obtained by being received by the image sensor  803  into the areas based on the respective patterns of the modulator  2502 . Namely, the image dividing unit  208  of the gesture detecting unit  206  divides the image data in accordance with the plurality of patterns included in the photographing pattern  805 . 
     In the example of  FIG.  16   , an output of the image sensor is divided into 2×2 areas. Since the subsequent processes of the image processing unit  209  are similar to those in  FIG.  17    and  FIG.  18   , explanation thereof will be omitted. For example, the distance measurement processing unit  210  adjusts the developing pattern  1501 , and the image processing unit  209  executes the calculation again, thereby obtaining the distance to the arbitrary position. 
     Thus, the modulator  2502  has the photographing pattern  805  provided on the light receiving surface of the image sensor  803  to modulate intensity of light. Namely, the gesture detecting unit  206  calculates the distance between the photographing pattern  805  and the point  2401  as described above, thereby it is possible to calculate the distance. As described above, the gesture detecting unit  206  restores the image by the calculation based on the second pattern in a divided image unit, and obtains the image for detecting gesture of the user. Note that the gesture detecting unit  206  does not restore the image in the divided image unit, but may collectively restore the image by means of a known calculation technique. 
     In the present embodiment, near infrared light is utilized as a light source that is installed in the image display apparatus  101 A. By irradiating the near infrared light to the target object, it becomes possible to measure the distance even in a dark room. In order to block unnecessary visible light, infrared light reflected by the photographic subject is transmitted to the distance measuring sensor, and an infrared transmitting filter or a bandpass filter for blocking visible light is installed, for example.  FIG.  22    and  FIG.  23    illustrate installation examples of the infrared transmitting filter. 
       FIG.  22    is a view in which the modulator  2502  is installed on the image sensor  803  and an infrared transmitting filter  2601  is installed thereon.  FIG.  23    is a view in which the infrared transmitting filter  2601  is installed next to the image sensor  803  and the modulator  2502  is installed thereon. By installing this filter, it is possible to block unnecessary light, and this makes it possible to receive only infrared ray reflected light from the target object. 
     Next, a method of shifting a gesture recognition area in order to improve usability of a gesture operation in the head mounted image display apparatus, for example, by setting a position at which the gesture operation is carried out outside a visual field range of the user to realize a more natural operation will be described.  FIG.  24    illustrates an example in which the distance measuring sensor unit  102  is installed at a central portion of the pair of eyeglasses so as to be parallel to the image display unit as illustrated in  FIG.  1   . 
     At this time, a visual field of the distance measuring sensor, that is, the gesture recognition area is defined as an area indicated by a reference numeral “2803”.  FIG.  25    illustrates an example in which the distance measuring sensor unit  102  is installed so as to be diagonally inclined by an installation angle θ from a reference position in order to shift the gesture recognition area. In this case, the gesture recognition area becomes an area indicated by a reference numeral “2804”, and the gesture recognition area illustrated in  FIG.  24    becomes an area obtained by shifting it by the angle θ. 
     As described above, the modulator  2502  of the distance measuring sensor unit  102  has the photographing pattern  805  that includes the plurality of patterns that are different from each other, and modulates intensity of light. The gesture detecting unit  206  divides the image data obtained by receiving the light transmitted through the modulator  2502  by the image sensor  803  in a divided unit; restores the image by the calculation based on the developing pattern  1501  corresponding to the photographing pattern  805 ; and obtains the image for detecting gesture of the user. This makes it possible to obtain the image of the object in the outside world without using the lens for forming an image. Therefore, it is possible to reduce a load on a user when the user wears the apparatus. Namely, it becomes possible to realize a small image display apparatus that can recognize gesture in the optimal gesture recognition area. 
     Second Embodiment 
     Subsequently, a second embodiment will be described. The present embodiment is different from the first embodiment in a configuration and an installing method of a distance measuring sensor unit  102 . Compared with the first embodiment, it is indicated that a further small image display apparatus  101  can be realized. 
       FIG.  26    illustrates a basic configuration of the distance measuring sensor unit  102 . First, a center of an effective area of an image sensor  803  is defined as a sensor center (image sensor center) A normal vector with respect to an image sensor surface at the sensor center is defined as a sensor optical axis. A center of a photographing pattern  805  is defined as a pattern center. The image sensor  803  and the photographing pattern  805  are installed so that they are parallel to each other and the sensor optical axis matches the pattern center. A distance therebetween is set to d F . 
     At this time, a visual field of a distance measuring sensor, that is, a gesture recognition area becomes an area  3003  indicated by a straight line that passes through an end of the image sensor  803  and the pattern center.  FIG.  27    illustrates a configuration of the distance measuring sensor according to the present embodiment in a case where this is a basic configuration. The photographing pattern  805  is installed at a position obtained by shifting the pattern center from the sensor optical axis by a shift angle θ. Here, a shift amount δ F  can be expressed by δ F =d F  tan θ (Formula (13)). 
     At this time, the gesture recognition area becomes an area  3103  indicated by a straight line that passes through an end of the image sensor  803  and the pattern center. Thus, compared with  FIG.  26   , it is possible to shift a center of the gesture recognition area by δ F , and this makes it possible to reduce protrusion of a distance measuring sensor portion in a case where the sensor is diagonally installed. 
     Here, a photographing pattern center will be described.  FIG.  28    illustrates one example of a photographing pattern. As illustrated in  FIG.  16   , the photographing pattern is configured so that a plurality of initial phase patterns is two-dimensionally arranged. Centers of concentric circle patterns are respectively indicated by reference numerals  3201 ,  3202 ,  3203 , and  3204 . A point that becomes the center of gravity of a shape obtained by connecting the centers of the concentric circle patterns  3205 ,  3205  is indicated by a reference numeral  3206 , and this point  3206  becomes the photographing pattern center. 
     An example of a shifting method of the photographing pattern will be described with reference to  FIG.  29    and  FIG.  30   . In case of  FIG.  29   , a modulator  2502  itself is shifted with respect to the image sensor  803  and is installed so that the photographing pattern center is shifted as described above. On the other hand, in case of  FIG.  30   , a position of the modulator  2502  itself is not changed, and only the photographing pattern is shifted. In any case, the similar effect can be obtained by shift of the photographing pattern as described above. 
     Further, by shifting the photographing pattern center in this manner, an image processing unit  209  executes a process to shift an image segmenting position at the time of development processing in accordance with the shift amount and segment an image. 
     According to the configuration described above, compared with a case where the distance measuring sensor is diagonally installed in the head mounted image display apparatus illustrated in the first embodiment, it becomes possible to realize a small image display apparatus. Further, as described above, the image display apparatus  101 A can realize a more natural operation by shifting the position of the photographing pattern  805  and setting the position at which a user carries out a gesture operation to be outside a visual field range of the user. As a result, the image display apparatus  101 A can improve usability of the gesture operation. 
     Third Embodiment 
     The present embodiment is different from the first embodiment in that a position of a modulator  2502  or a position of a photographing pattern  805  of the modulator  2502  is dynamically shifted. An example of a head mounted image display apparatus  101  is illustrated. For example, it is illustrated that usability of a user is improved by dynamically shifting a gesture recognition area so that the user is allowed to carry out a natural gesture depending upon a posture state such as an upright position or a sitting position. 
       FIG.  31    is a view illustrating a functional configuration of an image display apparatus  101 B according to a third embodiment. A basic configuration thereof is similar to that illustrated in  FIG.  2   . The image display apparatus  101 B further includes a sensor unit  3504 , a posture detecting unit  3503  (or a posture specifying unit) configured to detect posture of the user on the basis of information obtained by the sensor unit  3504 , a gesture recognition area determining unit  3505 , and a distance measuring sensor control unit  3502  (a modulator control unit or liquid crystal display control unit). 
     Here, the sensor unit  3504  is a gyro sensor or a nine-axle sensor, for example, and is a part for obtaining information indicating a state of the user. By installing the head mounted image display apparatus  101 B, for example, information on angular velocity, acceleration, or terrestrial magnetism is obtained. However, the sensor unit  3504  may be any sensor so long as the state of the user is obtained. The sensor unit  3504  transmits sensor information to the posture detecting unit  3503 . 
     The posture detecting unit  3503  is a part for obtaining sensor information from the sensor unit  3504  and detecting a posture of the user on the basis of the sensor information. The posture detecting unit  3503  is realized by a CPU or the like, for example. The posture detecting unit  3503  transmits a detection result to the distance measuring sensor control unit  3502 . 
     The gesture recognition area determining unit  3505  is a part for determining a suitable gesture recognition area in accordance with the posture detected by the posture detecting unit  3503 . The gesture recognition area determining unit  3505  is realized by a CPU or the like. The gesture recognition area determining unit  3505  obtains the detection result from the posture detecting unit  3503 , and determines the gesture recognition area on the basis of the obtained result. When the gesture recognition area is determined, the gesture recognition area determining unit  3505  transmits a signal indicating a shift instruction of a modulator  2502  in a distance measuring sensor unit  102  or a photographing pattern  805  to a distance measuring sensor control unit  3502  on the basis of the determination. 
     The distance measuring sensor control unit  3502  is a part for shifting the position of the modulator  2502  included in the distance measuring sensor unit  102  or the photographing pattern  805 . The distance measuring sensor control unit  3502  is a part for shifting the position of the modulator  2502  in the distance measuring sensor unit  102  or the photographing pattern  805  on the basis of an instruction signal obtained from the gesture recognition area determining unit  3505 . The distance measuring sensor control unit  3502  is realized by a CPU or the like. When the instruction signal is obtained from the gesture recognition area determining unit  3505 , the distance measuring sensor control unit  3502  shifts the modulator  2502  in the distance measuring sensor unit  102  or the photographing pattern  805  on the basis of the instruction signal. 
     A processing flow of the image display apparatus  101 B illustrated in  FIG.  31    (a processing flow according to the third embodiment) will be described with reference to  FIG.  32   . At Step S 31 , the posture detecting unit  3503  detects a posture of the user such as an upright position, a sitting position, a supine position, or a lateral position, for example, by using user information obtained by the sensor unit  3504 . Next, at Step S 32 , the gesture recognition area determining unit  3505  determines a suitable gesture recognition area based on the detected posture. At Step S 33 , the distance measuring sensor control unit  3502  executes a control (modulator control) of a position of the modulator  2502  or a position of the photographing pattern  805  of the modulator  2502 , which corresponds to the gesture recognition area. The subsequent processes at Steps S 34  to S 37  are respectively similar to those in  FIG.  3   . 
     Here, the example in which the gesture recognition area is determined in accordance with the posture has been described. As another example, the image display apparatus  101 B may include input means (or a setting unit) via which the user designates a gesture recognition area (or a shift amount). The gesture recognition area may be designated in accordance with a hand by which the user carries out gesture (right hand or left hand), or the gesture recognition area may be designated in accordance with an application used by the user. 
     By designation of the area, at least one of a shift direction or an angle can be designated. Since the gesture recognition area can be set flexibly in this manner, it is possible to realize a natural gesture operation in accordance with usage environment of the user, and this makes it possible to improve usability thereof. 
     Next, a shift example of the photographing pattern  805  of the modulator  2502  will be described with reference to  FIG.  33    and  FIG.  34   . These are drawings when the distance measuring sensor unit  102  installed in the image display apparatus  101 B is viewed from a side of the image display apparatus  101 B. 
     In the example of  FIG.  33   , with respect to an image sensor  803 , the modulator  2502  is shifted to a position in an upper direction or a position in a lower direction in  FIG.  33   . Along with this, the photographing pattern  805  is shifted to a position in the upper direction or the lower direction. The photographing pattern  805  shifted in the upper direction becomes a photographing pattern  805 A. Further, the photographing pattern  805  shifted in the lower direction becomes a photographing pattern  805 B. 
     For example, in a case where the user is at an upright position and wants to carry out a gesture operation at an upper side, the modulator  2502  is shifted to a position in the upper direction. In a case where the user is in a sitting position and it is assumed that the user is sitting on a chair and carries out a gesture operation on a desk, for example, it is good usability for the user when the gesture recognition area is shifted downward from a front face of the user. Therefore, the photographing pattern  805  of the modulator  2502  is shifted to a lower position. These are one example of the upright position and the sitting position. By shifting the position of the modulator  2502  so as to become a natural gesture operation in accordance with a posture of the user, it is possible to dynamically change the gesture recognition area. 
     In the example of  FIG.  34   , with respect to the image sensor  803 , the photographing pattern  805  of the modulator  2502  is shifted to a position diagonally lower left in  FIG.  34   , or the photographing pattern  805  of the modulator  2502  is shifted to a position diagonally lower right in  FIG.  34   . For example, in a case where a gesture operation is carried out by the left hand, the modulator  2502  is shifted to the position diagonally lower left in  FIG.  34   , and the photographing pattern  805  is thereby shifted (a photographing pattern  805 C). In a case where a gesture operation is carried out by the right hand, the modulator  2502  is shifted to the position diagonally lower right in  FIG.  34   , and the photographing pattern  805  is thereby shifted (a photographing pattern  805 D). By shifting the position of the modulator  2502  so as to become a natural gesture operation in accordance with the hand by which the user carries out gesture in this manner, it is possible to dynamically change the gesture recognition area. 
     Here, the method of shifting the position of the modulator  2502  may be a method of mechanically shifting the modulator  2502 , or may be a method of electrically shifting only the pattern. However, in a case where the modulator  2502  is shifted mechanically, a mechanism for moving the modulator  2502  is required, and there is a possibility that this causes an increase in a size of the apparatus. 
     Therefore, a method of electrically shifting only a pattern inexpensively will be described.  FIG.  35    illustrates a configuration of the image sensor  803 . A plurality of photographing patterns  805  is realized on the modulator  2502 . This may be ones obtained by adhering a film that is realized by printing or the like. A liquid crystal display  3901  is arranged thereon. As illustrated in  FIGS.  36 ( a ) and  36 ( b ) , in this liquid crystal display, a portion through which light is transmitted is indicated by white, and a portion in which light is blocked is indicated by black. By switching the liquid crystal display  3901 , it becomes possible to display the photographing pattern of the position corresponding to the portion through which light is transmitted as illustrated in  FIGS.  37 ( a ) and  37 ( b )  when the liquid crystal display  3901  is combined with the modulator  2502 . This makes it possible to dynamically shift the photographing pattern of the modulator  2502 . 
     In this case, the distance measuring sensor control unit  3502  defines a portion in which light is blocked on the basis of a detection result by the posture detecting unit  3503 , and controls the liquid crystal display  3901  of the distance measuring sensor unit  102 . Further, the distance measuring sensor control unit  3502  notifies the gesture detecting unit  206  of the blocked portion. The gesture detecting unit  206  specifies a photographing pattern of the portion through which light is transmitted, which is specified by the blocked portion, and generates a developing pattern corresponding to the photographing pattern. 
     According to the configuration described above, the image display apparatus  101 B changes the position of the photographing pattern  805  in accordance with the posture of the user, whereby it is possible to adjust an area where the user is expected to carry out gesture. Namely, the image display apparatus  101 B dynamically shifts the gesture recognition area, for example, in accordance with a posture situation of the user such as the upright position or the sitting position or the hand by which the gesture is carried out, whereby it is possible to improve usability of the user. 
     Fourth Embodiment 
     An embodiment of a structure of a distance measuring sensor used in a head mounted image display apparatus  101  according to the present invention is illustrated to indicate that enlargement of a visual field is realized. 
     The present embodiment is different from the first embodiment to the third embodiment in that a structure of the distance measuring sensor illustrated in the first embodiment to the third embodiment is modified. 
       FIG.  38    illustrates a basic structure of an image sensor  803  in a distance measuring sensor unit  102 . As illustrated in  FIG.  38   , the image sensor  803  includes a light receiving element array  4201  and a microlens array  4202 .  FIG.  39    illustrates a part of this.  FIG.  39    is a view illustrating a part of the light receiving element array  4201  and the microlens array  4202 .  FIG.  39    illustrates a light receiving element  4301  corresponding to one pixel of the light receiving element array  4201  and one microlens  4302  of the microlens array  4202 . Note that a center of the microlens  4302  is referred to as a “center  4303 ”. This microlens  4302  has a role of focusing light on the light receiving element  4301 .  FIG.  39    illustrates a state when a parallel light flux enters the microlens  4302 . Next, a chief ray incident angle characteristic (CRA characteristic: Chief Ray Angle characteristic) will be described with reference to  FIG.  40    and  FIG.  41   . 
       FIG.  40    is a view illustrating an example of reception of light at a standard incident angle. As illustrated in  FIG.  40   , a parallel light flux  4403  can be focused on the light receiving element  4301  and thereby received.  FIG.  41    is a view illustrating an example of reception of light in a case where an incident angle is large. As illustrated in  FIG.  41   , a parallel light flux  4504  when the incident angle becomes large is not focused on the light receiving element  4301 , and cannot thereby be received. Further, an electrode  4304  for extracting electric charge from the light receiving element  4301  is arranged between the light receiving element  4301  and the adjacent light receiving element  4301 . Therefore, the focused light is blocked by the electrode  4304 , whereby the focused light cannot be received by the adjacent light receiving element  4301 . 
     In other words, in the present embodiment, the angle of the parallel light flux  4403  illustrated in  FIG.  40    becomes a limit angle at which light can be received, and this influences a receivable angle range of the image sensor, that is, the CRA characteristic. 
     In view of the foregoing, a gesture recognition range when the modulator  2502  is shifted as described in the second embodiment or the third embodiment will be described with reference to  FIG.  42   .  FIG.  42    is a view for explaining the gesture recognition range when the modulator  2502  is shifted. Rays incident from an area  4604  illustrated in  FIG.  42    becomes a range in which the rays can be received by the light receiving element array  4201 . Rays incident from an area  4605  cannot be received on the light receiving element array  4201 . Therefore, depending upon the CRA characteristic, even though a visual field direction can be shifted, the visual field is limited. 
     An arrangement example of the light receiving element array  4201  and the microlens array  4202  according to the present embodiment will be described with reference to  FIG.  43   .  FIG.  43    is a view illustrating an arrangement example of the light receiving element array  4201  and the microlens array  4202 . This becomes a structure in which the whole microlens array  4202  is shifted evenly. Here,  FIG.  44    illustrates a part of the light receiving element array  4201  and the microlens array  4202 .  FIG.  44    is a view illustrating a part of the light receiving element array  4201  and the microlens array  4202 . 
     A center  4804  of a microlens is shifted by a shift angle θ from the center  4303  of the microlens illustrated in  FIG.  39    (that is, the center before shift). This shift amount is the same as the shift angle in the modulator  2502 . Namely, when a normal vector with respect to an image sensor surface at the center of each light receiving element is set to a light receiving element optical axis, they are installed so that the light receiving element array  4201  becomes parallel to the microlens array  4202 , and a microlens center is at a position evenly shifted from the light receiving element optical axis in the same direction as a direction in which the pattern center is shifted from a center of the image sensor. Further, a shift amount of the center of the microlens becomes δ L . When a distance between the image sensor and the microlens array is set to d L , it can be expressed by δ L =d L  tan θ (Formula (14)). Thus, they are installed so that the microlens center is at a position evenly shifted from the light receiving element optical axis by the angle θ. 
     As a result, as illustrated in  FIG.  45   , it becomes possible to receive a light flux obtained by setting the parallel light flux  4504  that cannot be received in  FIG.  42    to an optical axis. 
     According to the configuration and the method described above, it becomes possible to enlarge the gesture recognition range. It does not become a problem in a case where an image sensor with a high CRA characteristic is utilized. However, the present system allows to secure an optimal visual field. 
     The present invention is not limited to the image display apparatus  101 A or the image display apparatus  101 B described in the first embodiment to the fourth embodiment described above. A function by the display unit and a function to calculate image data may be divided by a communicating unit. 
     For example, as illustrated in  FIG.  46   , an image display apparatus  101 C may be configured so that an apparatus including the distance measuring sensor unit  102 , the image display unit  103 , and the light source unit  104  is connected to a calculating unit  107  having functions to calculate image data (for example, a terminal device such as a smartphone) by a wired or wireless communicating unit  106 . 
     In this case, image data obtained by the distance measuring sensor unit  102  may be compressed and transmitted to the calculating unit  107 . 
     Note that the present invention is not limited to the embodiments described above, and various modifications are contained. For example, the embodiments described above have been explained in detail for explaining the present invention clearly. The present invention is not necessarily limited to one that includes all configurations that have been explained. 
     Further, a part of the configuration of one embodiment can be replaced by a configuration of the other embodiment. Further, a configuration of the other embodiment can be added to a configuration of one embodiment. 
     Further, a part of the configuration of each of the embodiments can be added to the other configuration, deleted, or replaced thereby. 
     Further, a part or all of the respective configuration described above, the functions, processing units, and processing means may be realized by hardware that is designed by an integrated circuit, for example. Further, the respective configuration described above and the functions may be realized by software so that a processor interprets programs realizing the respective functions and execute the interpreted programs. Information on programs, tables, and files, which realize the respective functions, can be placed in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD. 
     Further, control lines and information lines are illustrated so long as they are thought to be necessary for explanation. All of the control lines and the information line are not necessarily illustrated on a product. In fact, it may be considered that almost all of the components are connected to each other. 
     INDUSTRIAL APPLICABILITY 
     The present invention can be utilized for an apparatus that displays an image. 
     REFERENCE SINGS LIST 
       101 ,  101 A,  101 B . . . image display apparatus,  102  . . . distance measuring sensor unit,  103  . . . image display unit,  104  . . . light source unit,  106  . . . communicating unit,  107  . . . calculating unit,  203  . . . entire control unit,  204  . . . light source control unit,  206  . . . gesture detecting unit,  208  . . . image dividing unit,  209  . . . image processing unit,  210  . . . distance measurement processing unit,  213  . . . gesture recognizing unit,  214  . . . image display control unit,  216  . . . camera control unit,  217  . . . camera unit,  2502  . . . modulator,  3502  . . . distance measuring sensor control unit,  3503  . . . posture detecting unit,  3504  . . . sensor unit,  4201  . . . light receiving element array,  4202  . . . microlens array,  4301  . . . light receiving element,  4302  . . . microlens.