JP2006287383A - Information transmission system, imaging device, and light receiving control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the cost reduction of a light receiving unit by reducing a memory capacity, an improving a data rate, thus spreading usage. <P>SOLUTION: The light receiving unit is provided with an imaging means (27) which has a light receiving plane composed by arranging many photoelectric conversion elements in a matrix shape, shutter means (38, 39) which have many shutter regions (E1 to E4) arranged on the light receiving plane of the imaging means, and piled up on the photoelectric conversion elements at a proportion of per N piece of the photoelectric conversion elements, a 1st control means which alternately controls the open state and the closed state of each shutter region of the shutter means along an arrangement order, a 2nd control means which controls each shutter region of the shutter means in the reverse state of control by the 1st control means, and a 3rd control means which selectively executes control by the 1st control means and control by the 2nd control means following a predetermined pattern series in a imaging period of one time of the imaging means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides information transmission that can be used for various purposes such as product descriptions at stores, descriptions of exhibits at museums and exhibitions, landmark displays for buildings, advertisement displays, and the display of crowded facilities such as amusement parks. The present invention relates to a system, an imaging apparatus, and a light reception control method.

  Conventionally, the presentation of information on products and exhibits, or the display of landmarks for buildings, advertisements, and the status of amusement parks such as amusement parks have been made exclusively of paper, banners, billboards, plates, etc. For the sake of convenience, it was called “Information Presentation”).

  However, this type of text-based information presentation increases the number of information presentation objects such as signboards when the number of information presentation objects is large, making the important objects inconspicuous and the correspondence between the information presentation objects and the information presentation objects. The relationship is also difficult to grasp, and incorrect information understanding, for example, the information on the product A may be misunderstood as the information on the product B. In addition, since text information written on the information presentation can be read by anyone with normal vision, limited information for only specific people (for example, purchase of goods) When presenting the price, maximum discount rate, etc.), take preservative measures such as encoding and writing, but too complex encoding is inconvenient and must be simplified, so the information conservation effect May fall and be easily read.

In order to solve such a problem, techniques as described below are considered.
That is, a logical determination is made on the bit string constituting the information to be transmitted, and one of two bit pattern sequences SA and SB prepared in advance is selected according to the determination result, and the light P is selected according to the selection result. A light-emitting unit that modulates the light P, generates a binarized signal corresponding to the intensity of the light, and the bit pattern sequence included in the binarized signal is one of the two bit pattern sequences This is a technique for generating a logic signal corresponding to the pattern series when corresponding to one and displaying required information on the display unit of the light receiving unit (see, for example, Patent Document 1).

JP 2003-179556 A

However, the above prior art is extremely useful in that the correspondence between the information presentation object and the information presentation object can be correctly grasped and the information preservation effect can be obtained, but the following points are improved. There was room for it.
For example, since the light receiving unit requires n planes having the same number as the bit number m of the pattern series (SA / SB), the capacity of the frame time series buffer is considerably increased. For example, in the case of a frame image of 640 × 480 pixels, since one pixel is composed of three colors of RGB and each has multi-gradation (for example, 8 bits), the number of bits per plane is 640 ×. Since 480 × 3 × 8 = 7,372,800 bits and n planes are required, the total capacity of the frame time series buffer is an enormous amount of 36,864,000 bits even if m = 5. become. Therefore, there is a problem in that the cost of the light receiving unit is increased and the practical use is greatly hindered.

  The light emitting unit sequentially extracts bits of the transmission information TX at the timing of the clock signal CK, and outputs the light P modulated with the first pattern series SA or the second pattern series SB corresponding to the bit value. On the other hand, the light receiving unit captures the light P at the timing of the image capture clock signal PCK synchronized with the clock signal CK of the light emitting unit, and sequentially captures the image into n planes of the frame time series buffer. This means that the data rate between the light emitting unit and the light receiving unit is uniquely determined by the period of the clock signal CK or the image capture clock signal PCK. The period of the clock signal CK or the image capture clock signal PCK corresponds to the frame rate of the imaging unit of the light receiving unit, and a typical frame rate of a CCD or the like is, for example, about 30 fps (frame / second). When the number of bits m of (SA / SB) is 5, the data rate is only about 6 bits per second. At such a data rate, only extremely simple information, for example, tag information and ID information of products can be sent. .

  Accordingly, the present invention provides an information transmission system, an imaging apparatus, and a light reception control method capable of reducing the memory capacity required for information acquisition by the receiving unit and increasing the data rate of receivable information to expand applications. The purpose is to provide.

According to the first aspect of the present invention, the information to be transmitted is converted into an optical signal to be lit in a predetermined pattern and output, and the information is restored from the predetermined pattern obtained by receiving the optical signal. In the information transmission system including the light receiving unit, the light receiving unit includes an image pickup unit configured by a plurality of photoelectric conversion elements arranged in a matrix, and receives light to the image pickup unit in units of the photoelectric conversion elements. A blocking unit for blocking, a blocking control unit for controlling the blocking unit based on the predetermined pattern, and a restoration for restoring the information from the optical signal obtained by the imaging unit as a result of being controlled by the blocking control unit Means.
According to a second aspect of the present invention, in the first aspect of the present invention, the blocking means includes a plurality of shutter regions that are superimposed on the photoelectric conversion elements at a ratio of one for each of the N photoelectric conversion elements. And first shutter control means for controlling the shutter regions alternately in an open state and a closed state in the order of arrangement, and the shutter regions in a state opposite to the control by the first shutter control means. A second cutoff control means for controlling, wherein the cutoff control means selectively executes control by the first cutoff control means and control by the second cutoff control means in accordance with the predetermined pattern. And
According to a third aspect of the present invention, in the first or second aspect of the invention, the light emitting unit is configured to logically determine a bit string that constitutes information to be transmitted, and according to a determination result by the logical determination unit Bit pattern sequence selection means for selectively selecting a bit pattern sequence from two bit pattern sequences having low correlation with each other, and intensity modulated according to the selection result by the bit pattern sequence selection means And an output control means for controlling to output the optical signal.
According to a fourth aspect of the present invention, in the imaging apparatus, an imaging unit configured by a plurality of photoelectric conversion elements arranged in a matrix, and a blocking unit that blocks light received by the imaging unit in units of the photoelectric conversion elements; A blocking control unit that controls the blocking unit based on a predetermined pattern; an optical signal acquisition unit that continuously acquires an optical signal modulated by the imaging unit as a result of being controlled by the blocking control unit; And an information conversion means for converting the optical signal continuously acquired by the signal acquisition means into information.
According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the blocking means includes a plurality of shutter regions overlaid on the photoelectric conversion elements at a ratio of one for each of the N photoelectric conversion elements. And a first shut-off control means for alternately controlling the shutter regions in an open state and a closed state along the arrangement order, and controlling each shutter region in a state opposite to the control by the first shut-off control means. And a second shut-off control means for selectively executing the control by the first shut-off control means and the control by the second shut-off control means according to the predetermined pattern. To do.
The invention according to claim 6 is based on a predetermined step and a blocking step of blocking light reception to the plurality of photoelectric conversion elements in units of the photoelectric conversion elements with respect to the plurality of photoelectric conversion elements arranged in a matrix. A blocking control step for controlling the blocking means, an optical signal acquisition step for continuously acquiring a modulated optical signal as a result of control in the blocking control step, and a continuous acquisition at the optical signal acquisition step. And an information conversion step for converting the optical signal into information.

In the first, fourth, and sixth aspects of the invention, the light receiving unit includes a plurality of photoelectric conversion elements arranged in a matrix based on a predetermined pattern of an optical signal transmitted from the light emitting unit side. Shut off in element units. Therefore, in the prior art, all photoelectric conversion elements used for all patterns can be selectively used according to the pattern, the memory capacity required for information acquisition is reduced, and the receivable information data Applications can be expanded by increasing the rate.
According to the second and fifth aspects of the present invention, the photoelectric conversion elements are interrupted in such a way that a large number of shutter regions overlaid on the photoelectric conversion elements are alternately arranged in the arrangement order at a ratio of one for every N photoelectric conversion elements. In addition, an open state, a closed state, and a state opposite to the control are selectively performed. Therefore, in the prior art, all photoelectric conversion elements used for all patterns can be selectively used according to the pattern, the memory capacity required for information acquisition is reduced, and the receivable information data Applications can be expanded by increasing the rate.
In the invention according to claim 3, by using in combination with the light emitting unit, for example, explanation of products at stores, explanation of exhibits at museums and exhibitions, display of landmarks of buildings, advertisement display, amusement parks such as amusement parks, etc. It can be used for various purposes such as congestion status display.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the specification or examples of various details and the illustration of numerical values, character strings, and other symbols in the following description are only for reference in order to clarify the idea of the present invention, and all or part of them may Obviously, the idea of the invention is not limited. In addition, a well-known method, a well-known procedure, a well-known architecture, a well-known circuit configuration, and the like (hereinafter, “well-known matter”) are not described in detail, but this is also to simplify the description. Not all or part of the matter is intentionally excluded. Such well-known matters are known to those skilled in the art at the time of filing of the present invention, and are naturally included in the following description.

<Configuration>
First, the configuration will be described.
FIG. 1 is a diagram showing the light emitting unit 1 and the light receiving unit 20. 2A is a front perspective view of the light receiving unit 20, FIG. 2B is a rear perspective view of the light receiving unit 20, and FIG.

  The light receiving unit 20 includes a body 21 having a shape suitable for holding, an optical lens unit 22, operation buttons 23 such as a shutter key (only one button is shown in the figure, but a plurality of buttons may be provided) and a liquid crystal. For example, it is an imaging device such as a digital camera configured by attaching a display 24 or the like. The light receiving unit 20 is carried by a user, and is used as desired by the user when the user reaches a position where the user can visually check the information presentation object. The number of light receiving units 20 corresponds to the number of users. A specific configuration of the light receiving unit 20 will be described later.

  FIG. 2 is an internal block diagram of the light emitting unit 1. The light emitting unit 1 includes a transmission data memory 2, a pattern data memory 3, a timing generator 4, a CPU (Central Processing Unit) 5, a light emitting unit 6, a light emitting window 7, and the like.

  The timing generator 4 generates a stable clock signal CK having a predetermined period synchronized with the image capture clock signal PCK generated by the timing generator 13 of the light receiving unit 8.

  The CPU 5 extracts the i-th bit of the transmission information TX stored in the transmission data memory 2 in synchronization with the clock signal CK from the timing generator 4, determines the bit value, and if it is a logic signal 1 While the first pattern series SA is extracted from the pattern data memory 3, if the logic signal is 0, the second pattern series SB is extracted from the pattern data memory 3, and the first pattern series SA or the second pattern series SB is extracted from the light emitting unit 6. The operation to output to is repeated for the number of bits f of the transmission information TX. The light emitting unit 6 performs a flashing operation of emitting light in the section of the logical signal 1 of the first pattern series SA or the second pattern series SB and turning off in the section of the logical signal 0, and time-sequentially through the light emission window 7. Light P having a luminance change pattern is output.

  The light emitting unit 1 takes out the data of the transmission information TX bit by bit at the timing of the clock signal CK, determines each bit value, and selects the first pattern sequence SA if the signal is the logic signal 1, while the logic signal 0 If so, the second pattern series SB is selected.

FIG. 3 is a diagram illustrating an example of the first and second pattern series (SA / SB). In this figure, for example, when arbitrary transmission information TX is a bit string “01011...”, The first and second pattern sequences SA for each bit (i, i + 1, i + 3...) Of TX. SB selection is
i bit = 0 → SB
i + 1 bit = 1 → SA
i + 2 bit = 0 → SB
i + 3 bit = 1 → SA
i + 4 bits = 1 → SA
In this case, the light emitting unit 6 of the light emitting unit 1 outputs light P having a time-series luminance change pattern of SB, SA, SB, SA, SA.

  FIG. 4 is an electrical internal configuration diagram of the light receiving unit 20. In this figure, the light receiving unit 20 includes an optical lens unit 22, a liquid crystal shutter 26, an imaging unit 27, a captured image buffer 28, a display buffer 29, a liquid crystal display 24, a timing generator 30, an operation button 23, a status notification LED (Light Emitting Diode). ) 31, CPU 32, pattern data memory 33, reference image buffer 34, correlation degree evaluation image buffer 35, binarization work buffer 36, data list memory 37 (update request list 37a, list entry 37b, bit buffer 37c), etc. It is comprised. In addition, about a power supply part (battery etc.), illustration is abbreviate | omitted.

  FIG. 5 is an external view of the imaging unit 27 including the liquid crystal shutter 26. The imaging unit 27 is a CCD, CMOS, or the like having a predetermined diagonal distance (for example, 1/4 inch, 1/3 inch, or 1/6 inch) in which a large number of photoelectric conversion elements (imaging pixels) 27a are arranged in a matrix. A two-dimensional image sensor is housed in a package 27b and unitized. The pins 27c protruding from the lower and side surfaces of the package 27b are inserted into the substrate and used. Further, an opening window 27d having a size slightly larger than the above diagonal distance is formed on the upper surface of the package 27b, and all the photoelectric conversion elements 27a are exposed to the outside through the opening window 27d, and the light receiving surface. 27e is formed. The exposed surface of the aperture window 27d (the array surface of the photoelectric conversion elements 27a) is a light receiving surface that receives light from the outside, and the imaging unit 27 converts the subject image formed on the light receiving surface into an electrical frame image signal. The converted image is output to the captured image buffer 28 at a period synchronized with the captured image clock signal PCK.

  In general, a light receiving surface such as a CCD is covered with an optical filter 27f for cutting off light having an unnecessary wavelength. However, in addition to the optical filter 27e, the imaging unit 27 of the present embodiment includes a liquid crystal shutter 26. There is a feature in having. That is, the imaging unit 27 of the present embodiment converts the subject image captured via the optical lens unit 22, the optical filter 27e, and the liquid crystal shutter 26 into an electrical frame image signal, and synchronizes with the captured image clock signal PCK. It is different from a normal one (for example, the imaging unit 10 of the prior art) in that it is output to the captured image buffer 28 in the cycle described above. In the illustrated example, the liquid crystal shutter 26 is placed on the light receiving surface of the imaging unit 27 and the optical filter 27e is overlaid thereon. However, the order of the liquid crystal shutter 26 and the optical filter 27e may be changed. However, the distance from the liquid crystal shutter 26 to the light receiving surface is preferably as short as possible. Considering the thickness of the optical filter 27e, the liquid crystal shutter 26 is placed on the light receiving surface and the optical filter 27e is placed on the order as shown in the figure. It is desirable to overlap).

  The liquid crystal shutter 26 encloses liquid crystal molecules between two transparent electrodes, and changes the direction of the liquid crystal molecules by turning on / off the electrode voltage so that the light transmittance can be changed in two steps, high and low. It is a device. When the liquid crystal molecules are aligned in the thickness direction of the shutter (also referred to as molecules standing), it becomes transparent (high transmittance / the shutter is open), and conversely when aligned in the lateral direction of the shutter (also referred to as molecules falling asleep). State (low transmittance / shutter closed). Although the relationship between the ON / OFF state of the electrode voltage and the direction of the liquid crystal molecules differs depending on the type of liquid crystal, in this embodiment, for convenience of explanation, the liquid crystal molecules are aligned in the thickness direction of the shutter and transparent when a high potential voltage is applied. Shall be in a state. That is, the shutter opens when the electrode voltage is turned on, and the shutter closes when the electrode voltage is turned off.

  Generally, the liquid crystal shutter is divided into a full-shutter type (where the entire liquid crystal is switched between transparent and non-transparent) used for stereoscopic (3D viewing) glasses and the like (hereinafter referred to as a shutter area). There are two types of matrix type that can individually control the transmittance. The liquid crystal shutter 26 used in this embodiment is the latter matrix type.

  FIG. 6 is a conceptual structural diagram of the liquid crystal shutter 26. In this figure, the square cells arranged in a matrix form represent the transparent electrodes Gg (g is group number 1 or 2), each serving as a shutter region. However, the back side electrode (common electrode) is hidden behind the front side electrode and is not visible. Liquid crystal is sealed between each electrode Gg and the common electrode, and a shutter region is formed for each electrode Gg. When no voltage is applied to the electrode Gg, the liquid crystal under the electrode Gg has high transmittance, and the shutter region at the position is closed. On the other hand, when a voltage is applied to the electrode Gg, the liquid crystal under the electrode Gg has a low transmittance, and the shutter region at that position is opened.

  In addition, a rectangular broken line frame drawn in a similar shape to each electrode Gg represents the photoelectric conversion element 27a of the imaging unit 27. That is, each electrode Gg (shutter region) of the liquid crystal shutter 26 and the photoelectric conversion element 27a of the imaging unit 27 have a one-to-one relationship.

  Two lines of transparent wiring (a first system wiring 26a and a second system wiring 26b) are routed around each electrode Gg. The first system wiring 26a is connected to the first group of electrodes G1, and the second system wiring 26b is connected to the second group of electrodes G2. A control voltage CT that changes between a low potential and a high potential at a predetermined timing is applied to the first group of electrodes G1 via the first system wiring 26a, and an inverter is applied to the second group of electrodes G2. A control voltage CT whose polarity is inverted at 26c is applied via the second system wiring 26b. The first group of electrodes G1 and the second group of electrodes G2 are arranged in a so-called “checkered pattern” alternately in the vertical and horizontal directions.

  FIG. 7 is a conceptual diagram of the open / close state of the liquid crystal shutter 26. In this figure, a white rectangle indicates an open shutter region, and a hatched rectangle indicates a closed shutter region. As shown in the figure, (a) in the high potential period of the control voltage CT, the shutter region at the position of the first group of electrodes G1 is in an open state (white rectangle), and the shutter region at the position of the second group of electrodes G2 is Closed state (rectangular with hatching). Conversely, (b) during the low potential period of the control voltage CT, the shutter region at the position of the first group of electrodes G1 is closed (hatched rectangle), and the shutter region at the position of the second group of electrodes G2 is open. (Open rectangle). Hereinafter, the state (a) is referred to as “lighting-only mask state” or simply “lighting-only mask state”, and the state (b) is referred to as “light-off-only mask state” or simply “light-off-only mask state”. I will say.

  FIG. 8 is an explanatory diagram of the principle of this embodiment. In this figure, (a) is a schematic diagram of a lighting-only mask 38 and a lighting-only mask 39. That is, the on-dedicated mask 38 shown in FIG. 7 schematically illustrates the state of the liquid crystal shutter 26 shown in FIG. 7A, and the off-only mask 39 shown in the figure is used as the liquid crystal shutter 26 shown in FIG. 7B. This is a schematic representation of the state. It should be noted that the lighting dedicated mask 38 and the lighting only mask 39 shown in the figure are selected from four 2 × 2 of the many shutter regions of the liquid crystal shutter 26 as representative examples. The upper left shutter area of the dedicated mask 39 when extinguished is E1, the upper right shutter area is E2, the lower left shutter area is E3, and the lower right shutter area is E4.

  As illustrated, the lighting-only mask 38 has upper left and lower right shutter areas E1 and E4 open, and upper right and lower left shutter areas E2 and E3 are closed. On the other hand, in the off-time exclusive mask 39, the upper left and lower right shutter areas E1 and E4 are closed, and the upper right and lower left shutter areas E2 and E3 are opened.

  Now, when the light P of the light emitting unit 1 is lit, when the light P is viewed through the lighting dedicated mask 38, the “lit state” can be seen from the portions E1 and E4. Further, when the light P of the light emitting unit 1 is turned off, when the light P is viewed through the dedicated mask 39 when turned off, the “light-off state” can be seen from the portions E2 and E3. These are the appearances of the correct combination (light P on-dedicated mask 38, light P off-off dedicated mask 39), and the light P blinking pattern and two masks (light-on dedicated mask 38 and light-off dedicated mask 39) The usage patterns (switching patterns) of the dedicated mask 39) match.

  On the other hand, the “lighting state” can be seen from the portions E2 and E3 when the dedicated mask 39 is turned off, or the “lighted state” is seen from the portions E1 and E4 when the dedicated mask 38 is turned on. If this is the case, the combination is incorrect. In this case, the blinking pattern of light P (not necessarily light P, which may be another light source) and the usage pattern (switching pattern) of two masks (lighting-only mask 38 and light-off dedicated mask 39) are as follows. Does not match.

  Based on the above, the relationship between the two usage patterns of the liquid crystal shutter 26 (light-on dedicated mask 38 / light-off dedicated mask 39) and the imaging unit 27 will be described.

  FIG. 9 is a diagram illustrating the relationship between the liquid crystal shutter 26 and the imaging unit 27. In this figure, it is assumed that the light P of the light emitting unit 1 has repeatedly blinked in units of predetermined slots (SLOTa to SLOTe). The slot length is the same, and the time Ta when all the slots are added corresponds to one frame of the imaging unit 27.

  Here, the blinking pattern of the light P is set to “ON” → “ON” → “OFF” → “ON” → “OFF”. If the lighting is logic 1 and the extinction is logic 0, this blinking pattern is 4-bit data (first pattern series SA) of “11010”. Two usage patterns of the liquid crystal shutter 26 are switched in synchronization with the 4-bit data. That is, when switching on sequentially, the lighting-only mask 38 is used for “lighting” and the lighting-only mask 39 is used for “turning off”. As shown in the figure, when SLOTa and SLOTb are turned on, A dedicated mask 38 is used. In the next SLOTc, the light-off dedicated mask 39 is used. In SLOTd, the light-off dedicated mask 38 is used again. In the last SLOTe, the light-off dedicated mask 39 is used.

  When the masks are switched in this way, for each slot (SLOTa to SLOTe), the image of the light transmitted through the lighting-time dedicated mask 38 or the lighting-only mask 39 is photoelectrically converted by the imaging unit 27, and finally one sheet The captured image buffer 28 stores the frame image.

  For simplification, the pixels (photoelectric conversion elements 27a) of the image pickup device 27 are simplified to be 2 × 2 pixels in the same manner as the masks (light-on dedicated mask 38 and light-off dedicated mask 39), If the pixels are represented by B1 to B4, in the SLOTa, SLOTb, and SLOTd using the lighting dedicated mask 38, photoelectric conversion is performed only in the pixels (B1, B4) corresponding to the open shutter regions E1, E4. I will not. Similarly, in SLOTc and SLOTe using the dedicated mask 39 at the time of extinction, photoelectric conversion is performed only in the pixels (B2, B3) corresponding to the open shutter regions E2, E3.

  Therefore, B1 data and B4 data among the data of each pixel of the frame image obtained at the time Ta of one frame are those when the dedicated mask 38 for lighting is used, and B2 data and B3 data are when the light is turned off. Since this is the case when the dedicated mask 39 is used, these pixel data are selectively read out from the captured image buffer 28, so that two images (lighted image 40 and unlit image 41) are obtained from one frame image. Obtainable.

  Then, the blinking pattern of the light P of the light emitting unit 1 can be determined using the on-image 40 and the off-image 41. A specific method of this determination will be described later in detail, but the basic idea is as follows.

  If the blinking pattern of the light P and the usage patterns of the two masks (dedicated mask 38 for lighting / dedicated mask 39 for extinguishing) match, the lighting image 40 includes bright spots with sufficient brightness. Such a bright spot should not be included in the off-image 41. Therefore, when such an on-image 40 and an off-image 41 are obtained, it can be seen that the blinking pattern of the light P is a known pattern (the same pattern as the mask switching pattern). On the other hand, if the lighting image 40 does not include a bright spot with sufficient brightness, or if the lighting image 41 includes such a bright spot, the light P It can be seen that the blinking pattern is an unknown pattern or unnecessary noise such as ambient light.

<Description of action>
Next, the specific operation of this embodiment will be described.
The main processing of the light receiving unit 20 according to the present embodiment is performed exclusively by the CPU 32. That is, the CPU 32 controls the shooting operation of the imaging unit 27 in synchronization with the image capture clock signal PCK from the timing generator 30, or displays the frame image captured from the imaging unit 27 in the captured image buffer 28 as it is as a display buffer. 29 to display the image on the liquid crystal display 24 as a through image, or to capture an image captured in the display buffer 29 in an image memory (not shown) when the operation button 23 such as a shutter button is operated. To go.

  In addition, the CPU 32 controls the liquid crystal shutter 26 during the photographing operation of the image pickup unit 27, and uses the usage patterns of the two masks (dedicated mask 38 when turned on / dedicated mask 39 when extinguished) as predetermined patterns (first pattern series SA or Switching processing is performed according to the second pattern series SB).

  Further, the CPU 32 takes out a frame image (an image taken while switching the mask) from the captured image buffer 28 and performs processing for generating the above-described lighting-time image 40 and the lighting-time image 41 from the one frame image. Complement processing is performed on each of the lighting image 40 and the light-off image 41 using a neighborhood image, and then addition / subtraction is performed on the image after the complement processing in consideration of the weight of the number of lights on and off in the pattern. After the result is stored in the correlation evaluation image buffer 35, a pixel region having a time-series luminance change pattern is extracted from the correlation evaluation image, and the luminance change pattern is binarized by the work buffer 36. The binarization process and the binarized data (corresponding to the digital signal PD) are held in the pattern data memory 33. Are compared with the reference pattern sequence (SAr / SBr), and when they coincide with SAr, a logic signal 1 is generated. On the other hand, when they coincide with SBr, a logic signal 0 is generated. A process of storing in the bit buffer 37c of the data list memory 37 is executed. Further, a bit string related to the light emitting area is generated from the logic signal stored in the bit buffer 37c, information is converted and restored, the liquid crystal display 24 is controlled, and the light emitting area by the light emitting unit 1 is included on the screen. In addition to displaying the subject image, a process is performed in which information relating to the light emitting area is displayed in an overlapping manner in a specific portion (for example, the center portion of the screen) of the display area, imitating a graphic such as a balloon.

  FIG. 10 is a diagram illustrating a specific usage situation of the light emitting unit 1 and the light receiving unit 20. In the figure, the light receiving unit 20 is directed at an angle of view α to the scenery in the city center. The buildings 42, 43, 44, the TV tower 45, the automobiles 46, 47, and the like enter the angle of view α, and the light emitting unit 1 is attached to the buildings 42, 44, the TV tower 45 (the bright spots 48 to 50). position). Although the user of the light receiving unit 20 cannot visually recognize the light emitting unit 1 itself, each light emitting unit 1 has light having a time-series luminance change pattern (first pattern series SA or second pattern series SB). P is emitted, and the bright spots 48 to 50 correspond to the light P. In addition to the bright spots 48 to 50 due to the light P, headlight light 51 of the automobile 46 is present in each image α as an example of disturbance light.

  The liquid crystal display 24 of the light receiving unit 20 includes buildings 42, 43, 44, TV tower 45 and cars 46, 47 images (building images 42A, 43A, 44A, TV tower image 45A, car image 46A, 47A), the bright spot images 48A to 50A, and the headlight light image 51A.

  The light receiving unit 20 extracts each of the bright spot images 48A to 50A, compares the brightness change pattern with each of the reference patterns (SAr / SBr), and generates a logic signal 1 if it matches SAr. If they match, a logic signal 0 is generated. Then, the bit string composed of the logic signal 1 and the logic signal 0 is converted into a character string, and the conversion result is displayed on the liquid crystal display 24 in an overlapping manner with a graphic 52 such as a balloon.

  The user of the light receiving unit 20 can obtain information such as the name of the building and the tenant from a remote location by using the light emitting unit 1 attached to various landmarks in the city area. Even if it is not a big thing like a building, if the light emitting unit 1 is attached to a product displayed at a store or an object displayed in a museum or exhibition, the description of the product name and the display Information can be obtained from a remote location.

  FIG. 11 is a flowchart of a light emission processing program executed by the CPU 5 of the light emitting unit 1. In this flowchart, the CPU 5 first extracts a predetermined amount, for example, 1 byte (8 bits) of information from the f-bit transmission information TX stored in the transmission data memory 2 (step S10). Next, the first 1 bit of the information is extracted (step S11) and logically determined (step S12). If the signal is logic signal 1, the light emitting unit 6 blinks in the first pattern sequence (SA) (step S13). If the signal is 0, the light emitting unit 6 blinks in the second pattern series (SB). Then, after the above process is repeated for one byte (step S15), the process returns to step S10 and is executed again, and the process ends when the end of the information is reached.

  FIG. 12 is a timing chart of the light emitting operation of the light emitting unit 1. In this example, a character string such as “X”, “T”, “o”, “w”, “e”,... Is assumed as transmission information TX, and a bit string corresponding to the character string (“X” in the figure). In this example, each bit of “→ 01011000) is converted into the first pattern series (SA: 11010) or the second pattern series (SB: 00101). The light emitting unit 6 of the light emitting unit 1 blinks in the first pattern series (SA: 11010) or the second pattern series (SB: 00101), and outputs the transmission information TX according to the blinking pattern.

  FIG. 13 is a timing chart of the light emitting side (light emitting unit 1) and the light receiving side (light receiving unit 20). On the light emitting side, the pattern switching clock CP is generated once every five clock signals CK. In the illustrated example, the first pattern series SA is selected at the first and second CP periods, and the second pattern series SB is selected at the third CP period. The waveform near the center of the drawing is the drive waveform of the light P. The light P is turned on in the high level period (logic 1 period) and turned off in the low level period (logic 0 period). For example, in the first CP cycle, the light P flashes in a pattern of “lighting” → “lighting” → “lighting off” → “lighting” every five slots (SLOTa to SLOTe).

  On the other hand, on the light receiving side, the operation is repeated every imaging cycle (frame) of the imaging unit 27. Here, the time Ta of one frame coincides with the period of one CP on the light emitting side, and the start and end of the frame coincide with the beginning and end of the CP period. That is, 1 CP on the light emitting side and 1 frame on the light receiving side are synchronized.

  The imaging unit 27 performs exposure (accumulation of charge in the photoelectric conversion element 27a) and readout of the charge from the photoelectric conversion element 27a in the period of one frame, and converts the charge into an electric signal (image signal). The image signal is transferred to the captured image buffer 28 at the beginning of the next frame. It should be noted that a necessary signal operation such as dark current correction is also performed when converting the charge into an image signal, but the description is omitted here.

  In the present embodiment, the liquid crystal shutter 26 is also controlled on the light receiving side. The control signal CT is a control signal for the liquid crystal shutter 26 as described above (see FIG. 4). When CT is at a high potential (hereinafter referred to as high level), the liquid crystal shutter 26 is in an open state in the shutter region at the position of the first group of electrodes G1 (see FIG. 7A), and CT is at a low potential (hereinafter referred to as “a”). In the liquid crystal shutter 26, the shutter region at the position of the second group of electrodes G2 is opened (see FIG. 8B). The former state is a “dedicated mask state when turned on”, and the latter state is a “dedicated mask state when turned off”.

  In the illustrated example, the control signal CT is at a high level in the first and second slots (SLOTa, SLOTb) and the fourth slot (SLOTd), and the third slot (SLOTc). And the fifth slot (SLOTe), the control signal CT is at a low level. Therefore, in SLOTa, SLOTb, and SLOTd, the liquid crystal shutter 26 is in the “lighting-only mask state”, and in SLOTe, the liquid crystal shutter 26 is in the “light-out dedicated mask state”.

  The control signal CT ′ is obtained by correcting the phase of the control signal CT by moving it forward by a predetermined amount Δs. Δs corresponds to the response delay time (several milliseconds) of the liquid crystal shutter 26. Throughout this specification, the control signal CT before phase correction is given to the liquid crystal shutter 26. However, this is for convenience of explanation. Actually, the control signal CT ′ after phase correction is given.

  The two waveforms 53 and 54 shown at the bottom in the figure show the opening and closing waveforms of the liquid crystal shutter 26, respectively. A solid-line waveform 53 is obtained when the “lighting-only mask state” is selected, and an alternate long and short dash line waveform 54 is obtained when the “light-off dedicated mask state”. In either case, the peak portions of the waveforms 53 and 54 are “dedicated mask state when turned on” or “dedicated mask state when turned off”. These waveforms 53 and 54 transition from mountain to valley or from valley to mountain in synchronization with the control signal CT (actually CT ′).

  Charges are accumulated in specific pixels (see B1 and B4 in FIG. 9) of the imaging unit 27 at the peak portions (A, B, D) of the waveform 53 corresponding to the “dedicated mask state during lighting”. Charges are accumulated in specific pixels (see B2 and B3 in FIG. 9) of the peaks 54 of the waveform 54 corresponding to the “time-only mask state”. In other words, the data for lighting image (see B1 data and B4 data in FIG. 9) and the data for lighting image (see B2 data and B3 data in FIG. 9) are accumulated in the period of one frame of the imaging unit 27. Therefore, pixel data of two images (light-on image 40 and light-off image 41) are included in one frame image created from these accumulated charges.

  FIG. 14 is a flowchart of a light receiving process program executed by the CPU 32 of the light receiving unit 20. When this flowchart is started, first, the timing generator 30 is initialized (step S20), and then the following processing is repeatedly executed.

Liquid crystal shutter control process: Step S21
In this liquid crystal shutter control process, first, a required shutter control pattern is read. This pattern corresponds to the blinking pattern of the light P of the light emitting unit 1 (first pattern series SA or second pattern series SB). Here, as an example, “11010” (first pattern series SA) is read. Next, a control signal CT is generated based on this shutter control pattern. This control signal CT is a signal that becomes a high level at a logic 1 of the control pattern and becomes a low level at a logic 0 (see the control signal CT in FIG. 13). Next, a control signal CT ′ in which the phase of the control signal CT is corrected by Δs is generated, the control signal CT ′ is output to the liquid crystal shutter 26, and the process is terminated.

Frame buffer registration processing: Step S22
FIG. 15 is a flowchart of the frame buffer registration processing subroutine program. In this flowchart, first, a frame image from the imaging unit 27 is taken into the captured image frame buffer 46 (step S22a), and then a filtering process such as smoothing is performed on the frame image (step S22b). Next, frame correlation processing is performed between the filtered frame image and the reference frame image in the reference image buffer 34. As a result, a motion vector is detected (step S22c), and the motion amount of the motion vector is corrected. It is determined whether it is within the threshold (step S22d).

  If the amount of motion of the motion vector is not within the correction threshold, it is determined that the frame image has no motion or has a small amount of motion, and the frame image is stored in the captured image buffer 28 as it is (step S22e). After the reference frame image in the image buffer 34 is replaced with this frame image (step S22f) and the same frame image is stored in the display buffer 29, the process returns to FIG. On the other hand, when the amount of motion of the motion vector is within the correction threshold, it is determined that this frame image has a large amount of motion, and motion correction is performed on this frame image, and the corrected frame image is After storing in the captured image buffer 28 (step S22g) and storing the same frame image in the display buffer 29, the process returns to FIG.

Signal detection & bit extraction processing: Step S23
FIG. 16 is a flowchart of the signal detection & bit extraction processing subroutine program. In this flowchart, first, the update request list 37a in the data list memory 37 is initialized (step S23a). Next, filter calculation of the on-image 40 and the off-image 41 is performed on the frame image stored in the capture image buffer 28 (step S23b), and the calculation result is used as the correlation evaluation image 35. (Step S23c).

FIG. 17 is a conceptual diagram of filter calculation. In this figure, the squares are pixels that are subject to filter calculation. Each pixel is given coordinates (x, y). Now, assuming that the vertical size of the frame image is H and the horizontal size is W, the range of the following formulas 1 and 2 is i = 0 to W / 2, j = 0 to H / 2.
Repeat with.

However, the coordinate position of (2i + 1, 2j + 1) corresponds to each dot of the on-image 40 (see B1 and B4 in FIG. 9), and the coordinate position of (2i + 2, 2j + 1) corresponds to each dot of the off-image 41 (FIG. 9). Corresponding to B2 and B3).
Further, the weight value Wa for each dot of the light-on image image 40 is set to 1/3, and the weight value Wb for each dot of the light-off image 41 is set to 1/2 (lighting 3 bits in the pattern, lighting 2 bits).
When the coordinate value is P (i, j), the correlation evaluation value R (i, j) of the coordinate (i, j) is
R (2i + 1, 2j + 1)... Correlation at coordinates corresponding to lighting image 40 = dot value at lighting / 3-dot value at lighting complemented by neighborhood average = (value of that coordinate) / 3− 4 neighborhood average of the coordinates / 2
= P (2i + 1,2j + 1)-(P (2i + 1,2j) + P (2i + 2j + l) + P (2i + 1,2j + 2) + P (2i + 2,2j + l)) / 4
... (Formula 1)
R (2i + 2, 2j + 1)... Correlation at the coordinates corresponding to the unlit image 41 = the dot value at the time of complementing from the neighborhood value / 3-the dot value at the time of the unlit = the 4-neighbor average of the coordinate / 3-( The value of the coordinate) / 2
= ((P (2i + 1,2j) + P (2i + 1,2j + l) + P (2i + 2,2j + 2) + P (2i + 3,2j + 1)) / 4) / 3-P (2i + 1,2j + l) / 2
.... (Formula 2)
Given in.

  Thereby, direct calculation from the captured image buffer 28 to the correlation degree evaluation image buffer 35 can be performed, and it is not necessary to prepare a buffer for the lighting-time image 40 and a buffer for the lighting-time image 41 separately.

  FIG. 18 is a conceptual diagram of acquiring the correlation degree evaluation image 55 based on the image difference between the lighting-time image 40 and the lighting-time image 41. In this figure, a weight value Wa (1/3) is applied to each pixel of the on-light image 40 by using a multiplier 56, and a weight value Wb (1/1) is also applied to the unlit image 41 by using a multiplier 57. 2) are applied and added by an adder 58 to obtain a correlation evaluation image 55 based on image differences. A checkered pattern 59 drawn inside the lighting-time image 40 represents an image of the light P (but lighting) obtained by the liquid crystal shutter 26 in the “lighting-only mask state”. A checkered pattern 60 drawn inside the image 41 represents an image of light P (however, extinguished) obtained by the liquid crystal shutter 26 in the “dedicated mask state when extinguished”. The small rectangles filled in black in the figures 59 and 60 are pixels corresponding to the closed shutter area (hereinafter referred to as closed pixels), and the small rectangles sandwiched between the black painted rectangles are in the open shutter area. It is a corresponding pixel (hereinafter referred to as an open pixel). However, here, for the convenience of illustration, closed pixels and open pixels in the background other than the light P are omitted by being hatched. A white-painted figure 61 drawn inside the correlation degree evaluation image 55 is a lighting image of the light P obtained by the image difference. The jaggedness of the graphics 59, 60 and 61 represents the boundary of the pixels (that is, the shutter region) of the image sensor 27.

When the correlation evaluation image 55 is generated in this way, a binarized image is generated again from the correlation evaluation image 55 in the correlation evaluation image buffer 35 in FIG. 16 (step S23d). Are labeled (labeled) with respect to the same continuous area, and the center coordinates of each area are additionally set as a first pattern series in the update request list 37a (step S23e).
Next, the threshold value of the correlation evaluation image 55 is inverted to generate a binarized image (step S23f). Similarly, each region is additionally set in the update request list 37a as the second pattern series ( Step S23g). Thereafter, it is determined whether or not the update request list 37a is not empty (step S23h). If it is not empty, the process proceeds to list update processing in step S25.

  FIG. 19 is a flowchart of the list update processing subroutine program. First, one pattern (hereinafter referred to as “request pattern”) is extracted from the update request list 37a set in step S23 (step S25a), and a pattern that matches the pre-registered coordinates exists in this request pattern. It is determined whether or not to perform (step S25b). If there is a match, it is determined whether this request pattern is the first pattern series SA or the second pattern series SB (step S25d).

  If the request pattern does not match both the first pattern series SA and the second pattern series SB, a new list entry 37b is created, the coordinate registration process and the bit buffer 37c are initialized (step S25c). The request pattern is determined (step S25d).

  If the request pattern is the first pattern series, “1” is added to the corresponding entry in the bit buffer 37c (step S25e). If the request pattern is the second pattern, “0” is added to the corresponding entry in the bit buffer 37c. "Is added (step S25f), and in any case, the above process is repeated until the process ends (step S25g), and the process proceeds to step S24 in FIG.

Display process: Step S24
FIG. 20 is a flowchart of the display processing subroutine program in step S24. In this flowchart, first, it is determined whether or not there is any bit data that has not been updated in the current update process (step S24a). If the bit data is not updated, the bit list is deleted from the data list memory 37 (step S24b). If the bit data is updated, it is determined whether or not 1-byte bit data is buffered in the bit buffer 37c. Determination is made (step S24c).

  If 1 byte (8 bits) is not buffered in the bit buffer 37c, the image in the display buffer 29 is sent to the liquid crystal display 24 for display (step S24e), and 1 byte (8 bits) is buffered in the bit buffer. In this case, after adding to the byte data FIFO (not shown) of the data list memory 37 and clearing the bit buffer 37c (step S24d), the image in the display buffer 29 is transferred to the liquid crystal display 24 and displayed (step S24e). . Next, the bright spot corresponding to the light P at the center is selected, and the information character string transmitted by the arrow and the light P is displayed overlapping the display image (step S24f). On the other hand, for the other bright spots, only the arrows are displayed in an overlapping manner (step S24g), and the process returns to the loop of FIG.

<Summary>
As described above, according to this embodiment, the light receiving unit 20 transmits the first pattern series SA or the second pattern series SB transmitted in the blinking pattern of the light P from the light emitting unit 1 within the period of one frame. Can receive. Therefore, if the length (Ta) of one frame is, for example, 66 ms and the information amount (the number of bits m) of the first pattern sequence SA or the second pattern sequence SB is m = 5, in this embodiment, 1 Data can be sent at 66 ms ÷ 5 = 13.5 ms per bit, and the data rate can be expected to be improved by m times compared to the case where only one bit can be sent per frame as in the prior art. This means that a lot of information can be transmitted in a short time, so it is possible to send more complex information as well as simple information (product tag information and ID information). It is possible to obtain a special effect that it is possible to expand use for various purposes.

  Further, the light receiving unit 20 of the present embodiment does not require components corresponding to the frame time series buffer 16 of the prior art. In addition, since the lighting-time image 40 and the lighting-time image 41 can be created from one frame image stored in the capture image buffer 28, the frame memory is also used for these images (the lighting-time image 40 and the lighting-time image 41). do not need. Therefore, the memory capacity can be greatly reduced as compared with the prior art. Therefore, it is possible to reduce costs and obtain a special effect that can eliminate one of the major obstacles in practical use.

  In addition, the light receiving unit 20 of the present embodiment only needs to provide the liquid crystal shutter 26 on the front surface of the existing image pickup unit 27, and there is no major change in configuration except for partial modification of the program. Therefore, this point also contributes to cost reduction. In addition, there is a merit that it can be easily applied to general-purpose imaging devices such as digital cameras.

  Further, since the control signal CT ′ whose phase is corrected in consideration of the response delay time (Δs) of the liquid crystal shutter 26 is used, inconvenience (such as a shift in shutter opening / closing timing) associated with the response delay of the liquid crystal shutter 26 can be prevented. Moreover, by adjusting the amount of phase correction, for example, it is possible to use a shutter device having a slow reaction speed (and therefore inexpensive), which also contributes to cost reduction.

  In addition, since the arrangement of the shutter area of the liquid crystal shutter 26 is made to be a “checkered pattern” in accordance with the pixels of the image pickup unit 27, the original resolution of the image pickup unit 27 is not impaired, and the balance of the aspect ratio of the image is maintained. A processing system can be assembled as it is.

<Modification>
In the above description, the light receiving unit 20 includes a liquid crystal finder (liquid crystal display 24) such as a digital camera, but is not limited thereto.

  FIG. 21 is a diagram illustrating an example of a light receiving unit that does not include a liquid crystal finder. As shown in this figure, the light receiving unit 67 may be provided with an optical lens 63 and operation buttons 64 in the body 62, and further provided with a display unit 65 for displaying character information and a direct view finder 66 for adjusting the photographing direction. .

  According to this, as shown in FIG. 6B, the information from the target is received and displayed on the display unit 65 by looking through the direct view finder 66 and directing the shooting direction toward the target and pressing the operation button 64. Can be displayed. In this way, it is not necessary to use a relatively expensive liquid crystal finder (the liquid crystal display 24 in FIG. 4), and the cost of the light receiving unit 67 can be reduced. Since the user cannot confirm the display on the display unit 65 while looking through the direct view finder 66, the user may issue an alarm or a synthesized voice for notifying acquisition of information from the target.

  In the above embodiment, the shutter area of the liquid crystal shutter 26 and the pixels of the imaging unit 27 are made to correspond one-to-one. However, the present invention is not limited to this.

  FIG. 22 is a diagram illustrating a modification of the liquid crystal shutter 26. In this figure, the shutter area 68 of the liquid crystal shutter 26 is indicated by a rectangle with a large solid line, and four (2 × 2) pixels 69 of the image pickup unit 27 are located under one shutter area. That is, in this example, one shutter area 68 of the liquid crystal shutter 26 is associated with four pixels 69 of the imaging unit 27, that is, a four-to-one relationship is established. Even in this case, the on-image 40 and the off-image 41 can be obtained without any trouble within one frame period of the imaging unit 27.

  In addition, by having such a many-to-one relationship, particularly when the liquid crystal shutter 26 is combined with the imaging unit 27 having a high pixel count (the shutter region 68 of the liquid crystal shutter 26 is adjusted in accordance with the small pixel 69). The cost increases as the size is reduced. In this case, when a frame image is obtained, first, it is necessary to perform a filtering process to obtain an average value of a plurality of dots and combine them into one dot value.

  FIG. 23 is a conceptual diagram of filter processing. Here, it is assumed that the number of pixels of the imaging unit 27 is 1280 × 960 dots. The original image 70 of 1280 × 960 is converted into a reduced image 71 having a size of 320 × 240 dots, for example, by filtering, and then the reduced image 71 is converted into the reduced image 71 as in the above embodiment. The correlation evaluation image 55 may be obtained by performing processing such as image separation and interpolation.

  In the above-described embodiment, the liquid crystal shutter 26 is always in either mask state (the dedicated mask state when the light is turned on or the dedicated mask state when the light is turned off).

  FIG. 24 is a view showing a preferred modification of the liquid crystal shutter 26. In this figure, the wiring 72 is connected to the first system wiring 26a of FIG. 6, and the wiring 73 is connected to the second system wiring 26b of FIG. The control signal CT generated by the liquid crystal shutter control signal generation unit 74 is applied to one input of the first OR element 75, and the CT whose polarity is inverted through the inverter 76 is converted to the second OR element 77. Meanwhile it has been added to the input. A mode selection signal ST from the shutter mode selection unit 78 is added to each other input of the first OR element 75 and the second OR element 77. In such a configuration, if the mode selection signal ST is kept at a low level, the same operation as in the above embodiment can be obtained. That is, if the control signal CT is set to a high level (high potential), a high potential is applied to the first group of electrodes G1 via the wiring 72 and the first system wiring 26a of FIG. If the control signal CT is set to a low level (low potential), the second group electrode G2 can be connected to the second group electrode G2 via the wiring 73 and the second system wiring 26b of FIG. A high potential (inverted) can be applied, and the liquid crystal shutter 26 can be put into a dedicated mask state when it is turned off.

  On the other hand, when the mode selection signal ST is set to the high level, the outputs of the two OR elements 75 and 77 can be set to the high level (high potential) regardless of the level of the control signal CT. Therefore, in this case, a high potential can be applied to the first group of electrodes G1 via the wiring 72 and the first system wiring 26a of FIG. 7, and the first potential can be applied via the wiring 73 and the second system wiring 26b of FIG. Since a high potential can also be applied to the two groups of electrodes G2, eventually all the shutter regions of the liquid crystal shutter 26 can be brought into an “open state”. As a result, the light receiving surface of the imaging unit 27 can be put into a non-masked state (open state). For example, when a photographing device such as a digital camera is used as the light receiving unit 20, the photographing device is usually used. Can be taken without any trouble. That is, the image capturing apparatus and the light receiving unit 20 can be completely used together.

  In the above embodiment, the shutter areas of the liquid crystal shutter 26 are arranged in a “checkered pattern”, but the present invention is not limited to this. In short, the open area and the closed area of the shutter region may be uniform or almost uniform and there is no partial bias. For example, the following may be used.

  FIG. 25 is a diagram illustrating another configuration example of the liquid crystal shutter 26. In this figure, electrodes 79 (also shutter regions) of the liquid crystal shutter 26 have a horizontally long rectangular shape, and the electrodes 79 are arranged at a predetermined pitch in the vertical direction or the horizontal direction (the vertical direction in the figure). And alternately connected to the first system wiring 80 and the second system wiring 81 alternately. A control signal CT is applied to the first system wiring 80, and a control signal CT whose polarity is inverted by an inverter 82 is applied to the second system wiring 81. The width of each electrode 79 is set so as to include the upper and lower two rows of pixels 83 of the imaging unit 27 under the electrode 79.

  In this way, the electrodes 79 (also shutter regions) arranged in the vertical direction or the horizontal direction (the vertical direction in the drawing) alternately open and close in accordance with the potential of the control signal CT, so-called “ Draw a “zebra pattern”. The “zebra pattern” has a slightly worse balance of pixel definition than the “checkered pattern”, but can have a simple electrode (shutter region) configuration, and the manufacturing cost of the liquid crystal shutter 26 can be reduced. It is also advantageous in that the aperture ratio of the imaging unit 27 is not reduced so much.

  Note that the width of each electrode 79 may be set so as to include three or more pixels 83 in the upper and lower portions of the imaging unit 27 under the electrode 79, or include one horizontal row of pixels 83. May be set.

  In the above embodiment, all the information (number of bits m) of the first pattern series SA or the second pattern series SB from the light emitting unit 1 is received within the period of one frame, but the number of bits m increases. In addition, there is a risk that it may become impossible to receive all within one frame period. In such a case, it may be as follows.

  26 and 27 show an improvement example corresponding to the case where the information amount (the number of bits m) of the first pattern series SA or the second pattern series SB is increased. In this figure, the light P from the light emitting unit 1 that has passed through the lens 84 is divided by the optical splitter 85 into light P1 traveling straight and light P2 bent 90 degrees. A first liquid crystal shutter 86 and a second liquid crystal shutter 87 that are complementarily controlled by the CPU 32 (one is controlled to be transmitted and the other is not transmitted) are provided at the ends of the respective lights P1 and P2. The light P 1 ′ and P 2 ′ transmitted through the liquid crystal shutters 86 and 87 are converted into image signals by the first imaging unit 88 and the second imaging unit 89.

  Here, if the first liquid crystal shutter 86 is used as a dedicated mask for lighting and the second liquid crystal shutter 87 is used as a dedicated mask for turning off, the two image pickup units 88 and 89 respectively receive the first frame images. 90 and a second frame image 91 are obtained.

  Therefore, by using these two images (the first frame image 90 and the second frame image 91) and performing separation filtering 92 and 93 as shown in FIG. 27, lighting for each frame image 90 and 91 is performed. The accumulated images 94 and 95 when off and the accumulated images 96 and 97 when turned off can be obtained, and the accumulated images 94 and 95 when turned on and the accumulated images 96 and 97 when turned off are added together by an adder 98. A degree evaluation image 55 can be obtained.

  With such a configuration, for example, even if 1 bit is diffused into a 10-bit pattern in the light emitting unit 1, it can sufficiently cope. This is because it is only necessary to shoot with two imaging systems (two systems of the first imaging unit 88 and the second imaging unit 89) for each 5 bits at the receiving side. Even if one bit is detected by combining two frames, it contributes to an increase in the frame rate. In general, if m> Fv, where m is the length of the pattern to be diffused and Fv is the number of frames required for detection, a significant increase in speed can be expected. This is effective when the highest noise resistance is realized (= the pattern length is long) and the frame rate of the imaging units 88 and 89 and the speed of the liquid crystal shutters 86 and 87 are limited.

FIG. 3 is a diagram showing a light receiving unit 20. 3 is an internal block diagram of the light emitting unit 1. FIG. It is a figure which shows an example of a 1st and 2nd pattern series (SA / SB). 3 is an electrical internal configuration diagram of a light receiving unit 20. FIG. 2 is an external view of an imaging unit 27 including a liquid crystal shutter 26. FIG. 2 is a conceptual structural diagram of a liquid crystal shutter 26. FIG. 3 is a conceptual diagram of an open / close state of a liquid crystal shutter 26. FIG. It is a principle explanatory view of this embodiment. FIG. 3 is a relationship diagram of a liquid crystal shutter and an imaging unit 27. It is a figure which shows the specific utilization condition of the light emission unit 1 and the light reception unit 20. FIG. It is a flowchart of the light emission processing program performed by CPU5 of the light emission unit 1. FIG. 3 is a timing chart of the light emitting operation of the light emitting unit 1. 4 is a timing chart of a light emitting side (light emitting unit 1) and a light receiving side (light receiving unit 20). 4 is a flowchart of a light receiving process program executed by a CPU 32 of the light receiving unit 20. It is a flowchart of a frame buffer registration processing subroutine program. It is a flowchart of a signal detection & bit extraction processing subroutine program. It is a conceptual diagram of filter calculation. It is an acquisition conceptual diagram of the correlation degree evaluation image 55 by the image difference of the image 40 at the time of lighting, and the image 41 at the time of extinction. It is a flowchart of a list update processing subroutine program. It is a flowchart of the display process subroutine program of step S24. It is a figure which shows an example of the light reception unit which is not provided with a liquid crystal finder. It is a figure which shows the modification of the liquid-crystal shutter. It is a conceptual diagram of a filter process. It is a figure which shows the preferable modification of the control relationship of the liquid-crystal shutter. 6 is a diagram illustrating another configuration example of the liquid crystal shutter 26. FIG. This is an improved example corresponding to the case where the information amount of the first pattern series SA or the second pattern series SB increases. This is an improved example corresponding to the case where the information amount of the first pattern series SA or the second pattern series SB increases.

Explanation of symbols

E1 to E4 Shutter area Gg Transparent electrode (shutter area)
1 Light emitting unit 20 Light receiving unit (imaging device)
26 Liquid crystal shutter (blocking means)
27 Imaging unit (imaging means)
27a photoelectric conversion element 27e light receiving surface 32 CPU (blocking control means, restoration means, first blocking control means, second blocking control means)
68 Shutter region 75 First OR element 75
77 Second OR element 77
78 Shutter mode selection unit 79 Electrode 86 First liquid crystal shutter 87 Second liquid crystal shutter 88 First imaging unit 89 Second imaging unit

Claims (6)

A light emitting unit that converts information to be transmitted into an optical signal that is lit in a predetermined pattern and outputs it, and a light receiving unit that restores the information from the predetermined pattern obtained by receiving the optical signal In an information transmission system,
The light receiving unit is
An imaging means composed of a plurality of photoelectric conversion elements arranged in a matrix;
Intercepting means for intercepting light reception to the imaging means in units of the photoelectric conversion elements;
Shut-off control means for controlling the shut-off means based on the predetermined pattern;
An information transmission system comprising: restoration means for restoring the information from the optical signal obtained by the imaging means as a result of being controlled by the blocking control means. The blocking means is composed of a large number of shutter regions overlaid on the photoelectric conversion elements at a rate of one for each N of the photoelectric conversion elements,
First shut-off control means for controlling each shutter region alternately in an open state and a closed state along the arrangement order thereof, and a first control for controlling each shutter region in a state opposite to the control by the first shut-off control means. A two-block control means;
2. The information transmission system according to claim 1, wherein the blocking control unit selectively executes control by the first blocking control unit and control by the second blocking control unit according to the predetermined pattern. The light emitting unit is
Logical determination means for logically determining a bit string constituting information to be transmitted;
Bit pattern sequence selection means for selecting a bit pattern sequence alternatively from two bit pattern sequences having a low degree of correlation with each other prepared in advance according to the determination result by the logic determination means;
The output control means which controls so that the intensity | strength modulated according to the selection result by this bit pattern series selection means may be output as a predetermined pattern, The output control means of Claim 1 or 2 characterized by the above-mentioned. Information transmission system. An imaging means composed of a plurality of photoelectric conversion elements arranged in a matrix;
Intercepting means for intercepting light reception to the imaging means in units of the photoelectric conversion elements;
Shut-off control means for controlling the shut-off means based on a predetermined pattern;
As a result of being controlled by this blocking control means, an optical signal acquisition means for continuously acquiring an optical signal modulated by the imaging means,
An imaging apparatus comprising: an information conversion unit that converts information from an optical signal continuously acquired by the optical signal acquisition unit into information. The blocking means is composed of a large number of shutter regions overlaid on the photoelectric conversion elements at a rate of one for every N photoelectric conversion elements, and the shutter regions are alternately opened along the arrangement order. And a first shut-off control means for controlling the shutter area to a closed state, and a second shut-off control means for controlling each shutter region in a state opposite to the control by the first shut-off control means,
The imaging apparatus according to claim 4, wherein the blocking control unit selectively executes control by the first blocking control unit and control by the second blocking control unit according to the predetermined pattern. For a plurality of photoelectric conversion elements arranged in a matrix,
A blocking step of blocking light received by the plurality of photoelectric conversion elements in units of the photoelectric conversion elements;
A blocking control step of controlling the blocking means based on a predetermined pattern;
As a result of being controlled in this blocking control step, an optical signal acquisition step for continuously acquiring a modulated optical signal,
A light reception control method comprising: an information conversion step of converting information obtained from the optical signal continuously acquired in the optical signal acquisition step into information.

Images