JP2009284128A - Data communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a data communication device which performs data communication using an image taken by an image sensor to perform faster data communication. <P>SOLUTION: The data communication device which performs the data communication using the image taken by the image sensor includes: the image sensor comprising a plurality of photoelectric converting elements receiving and converting incident light into electric charges, a plurality of charge storage units provided by the photoelectric converting elements, and a means for distributing the electric charges converted by the photoelectric converting elements to the plurality of charge storage units according to a reference frequency; an extracting means for extracting a data transmission light source emitting light of reference frequency from the image taken by the image sensor; a phase calculating means for calculating the phase of the light of reference frequency emitted by the data transmission light source extracted by the extracting means; and a decoding means for decoding transmission information based upon the phase calculated by the phase calculating means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a data communication apparatus, and more particularly to a data communication apparatus that performs data communication using an image captured by an image sensor.

  Conventionally, a data communication device that performs data communication using an image captured by an image sensor such as a CCD has been proposed (see, for example, Patent Document 1).

The data communication apparatus described in Patent Document 1 includes an image sensor that captures a light source that is controlled to be turned on and off so as to emit flashing light. As illustrated in FIG. image 30 _'1 continuous to, 30' _2, ..., from 30 _'n, by extracting the binary information represented by the brightness value that varies with on-off control of the light source, so as to perform data communication It has become.
JP 2004-32682 A

  However, in the data communication device described in Patent Document 1, an on or off-state light source is photographed every time (one frame) for acquiring one image, and based on a difference from a time-series continuous frame. Binary information is extracted. For this reason, when the light source is photographed at 60 frames / second, for example, there is a problem that only data of 60 bits / second can be transmitted and received at the maximum.

  The present invention has been made in view of such circumstances, and an object of the present invention is to enable higher-speed data communication in a data communication apparatus that performs data communication using an image captured by an image sensor.

  In order to solve the above problems, the present invention provides a data communication device that performs data communication using an image picked up by an image sensor, and receives a plurality of photoelectric signals that receive incident light and convert it into charges. An imaging device comprising: a conversion element; a plurality of charge storage units provided for each of the photoelectric conversion elements; and a unit that distributes the charges converted by the photoelectric conversion elements to the plurality of charge storage units based on a reference frequency And an extraction means for extracting a data transmission light source that emits light of a reference frequency from an image captured by the imaging device; and a phase of the light of the reference frequency emitted from the data transmission light source extracted by the extraction means And a decoding means for decoding transmission information based on the phase calculated by the phase calculation means.

  According to the first aspect of the present invention, light of a reference frequency (for example, light of a reference frequency whose phase is changed according to transmission information every predetermined time by the image sensor. That is, the transmission information is embedded. A data transmission light source that emits light) is extracted, the data transmission light source is extracted from the captured image, and the phase of the reference frequency light emitted from the extracted data transmission light source is calculated. The transmission information is decoded based on the calculated phase. Therefore, according to the first aspect of the present invention, in a data communication device that performs data communication using an image captured by an image sensor, information of a plurality of bits at a time (for example, a plurality of bits assigned for each changed phase) Information) can be transmitted and received, and data communication can be performed at a higher speed than in the past.

  According to a second aspect of the present invention, in the first aspect of the present invention, a difference between charges accumulated in the plurality of charge accumulation units is calculated, and the difference in an image captured by the imaging element exceeds a threshold value. The image processing apparatus further includes a determination unit that determines a pixel, and the extraction unit extracts the pixel determined by the determination unit as a data communication light source from an image captured by the imaging element.

  According to the second aspect of the present invention, for each photoelectric conversion element, a difference between charges accumulated in a plurality of charge storage units corresponding to the photoelectric conversion element is calculated, and the difference in the image captured by the image pickup element is calculated. It is possible to determine a pixel exceeding the threshold (that is, a pixel corresponding to the data transmission light source).

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the phase calculating unit transmits the data extracted by the extracting unit based on the charges accumulated in the plurality of charge accumulating units. The phase of the light of the reference frequency irradiated from the light source is calculated.

  According to the third aspect of the present invention, it is possible to calculate the phase of the light of the reference frequency emitted from the data transmission light source extracted by the extraction unit based on the charges accumulated in the plurality of charge accumulation units. It becomes.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the determination means is calculated by the calculation means among the pixels in which the difference in the image captured by the image sensor exceeds a threshold value. A group of pixels whose phase is equal to or less than a threshold and adjacent to each other is determined as one data transmission light source.

  According to the fourth aspect of the present invention, it is possible to prevent a plurality of pixels from being mistakenly extracted as one data transmission light source.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, further comprising image generation means for generating an image including the data transmission light source extracted by the extraction means. .

  According to invention of Claim 5, it becomes possible to produce | generate the image containing the data transmission light source extracted by the said extraction means. By using this image, it is possible to decode transmission information from the data transmission light source without being affected by background light. In addition, data communication can be performed simultaneously with a plurality of data transmission light sources. In addition, the number, position, size, distance, rotation, movement, phase, and the like of the data transmission light source can be grasped. Further, the load for these processes is reduced, and it is possible to increase the speed and reduce the circuit scale.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the data transmission light source is a light having a reference frequency whose phase is changed according to transmission information every predetermined time. It is characterized by irradiating.

  According to the sixth aspect of the present invention, the image sensor includes a data transmission light source (a data transmission light source that emits light of a reference frequency whose phase is changed according to transmission information every predetermined time). , Extract the data transmission light source from the captured image, calculate the phase of the light of the reference frequency irradiated from the extracted data transmission light source, and based on the calculated phase, transmit information Decoding is performed. Therefore, according to the sixth aspect of the present invention, in a data communication apparatus that performs data communication using an image captured by an image sensor, information of a plurality of bits at a time (information of a plurality of bits allocated for each changed phase) ) Can be transmitted / received, and higher-speed data communication can be achieved compared to the prior art.

  The invention according to claim 7 is the invention according to any one of claims 1 to 5, wherein the data transmission light source includes a first data transmission light source and a second data transmission light source, and the first data transmission light source is Irradiating light of a reference frequency, and the second data transmission light source emits light of a reference frequency whose phase is changed according to transmission information with respect to the light of the reference frequency emitted from the first data transmission light source. The phase calculating means includes a phase of light having a reference frequency emitted from the first data transmission light source, a phase of light having a reference frequency emitted from the second data transmission light source, and a position between these phases. A phase difference is calculated, and the decoding means decodes the transmission information based on the phase difference calculated by the phase calculation means.

  According to the seventh aspect of the present invention, an image including a data transmission light source (first data transmission light source and second data transmission light source) is captured by the imaging element, and the data transmission light source (first The data transmission light source and the second data transmission light source are extracted, and the phase of the light of the reference frequency emitted from the extracted data transmission light source (the first data transmission light source and the second data transmission light source) and the level of these phases are extracted. The phase difference is calculated, and the transmission information is decoded based on the calculated phase difference. Therefore, according to the seventh aspect of the present invention, in a data communication apparatus that performs data communication using an image captured by an image sensor, information of a plurality of bits at a time (information of a plurality of bits allocated for each changed phase) ) Can be transmitted / received, and higher-speed data communication can be achieved compared to the prior art.

  The invention according to claim 8 is the invention according to any one of claims 1 to 5, wherein the data transmission light source is a first data transmission light source and a second data transmission light source arranged in a predetermined positional relationship. And a third data transmission light source, wherein the first data transmission light source emits light of a reference frequency, and the second data transmission light source and the third data transmission light source are emitted from the first data transmission light source. The light of the reference frequency whose phase is changed according to the transmission information is irradiated to the light of the frequency, and the phase calculation unit is configured to output the phase of the light of the reference frequency irradiated from the first data transmission light source, the second The phase of the light of the reference frequency irradiated from the data transmission light source, the phase of the light of the reference frequency irradiated from the third data transmission light source, and the two data transmission light sources whose phase difference between the phases is equal to or less than the threshold Base Calculating a phase difference between the phase of the light of the frequency and the phase of the light of the reference frequency irradiated from the data transmission light source having a predetermined positional relationship with respect to the two data transmission light sources; The transmission information is decoded based on the phase difference between the phases calculated by the phase calculating means.

  According to the invention described in claim 8, an image including a data transmission light source (a first data transmission light source, a second data transmission light source, and a third data transmission light source) is captured by the imaging element, and the image is captured from the captured image. Data transmission light sources (a first data transmission light source, a second data transmission light source, and a third data transmission light source) are extracted, and two data transmission light sources (for example, a second data transmission light source and a third data transmission light source) having a phase difference equal to or less than a threshold value are extracted. ) And the phase of the light of the reference frequency emitted from the data transmission light source (for example, the first data transmission light source) having a predetermined positional relationship with the two data transmission light sources. The phase difference is calculated, and the transmission information is decoded based on the calculated phase difference. Therefore, according to the eighth aspect of the present invention, in a data communication apparatus that performs data communication using an image captured by an image sensor, information of a plurality of bits at a time (information of a plurality of bits allocated for each changed phase) ) Can be transmitted / received, and higher-speed data communication can be achieved compared to the prior art. Moreover, according to the invention described in claim 8, the phase of the light of the reference frequency emitted from the data transmission light source (for example, the first data transmission light source) having a predetermined positional relationship with respect to the two data transmission light sources, and The phase difference is calculated, and the transmission information is decoded based on the calculated phase difference. For this reason, it is possible to prevent or reduce the calculation of the phase difference from the erroneous data transmission light source (that is, decoding error).

  ADVANTAGE OF THE INVENTION According to this invention, in a data communication apparatus which performs data communication using the image imaged with the image pick-up element, higher-speed data communication is attained.

[First embodiment]
Hereinafter, a data communication apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
[Configuration of data communication device]
First, the configuration of the data communication apparatus of this embodiment will be described.

  FIG. 1 is a block diagram of the data communication apparatus of this embodiment.

  As shown in FIG. 1, the data communication device 1 of the present embodiment includes an optical time-of-flight distance image sensor 10 (hereinafter referred to as a distance image sensor 10). The distance image sensor 10 includes a light source 11, an image sensor 15, a control unit 16, a distance image generation unit 17, and the like.

  The light source 11 is a light source that irradiates the target space with light of the reference frequency fs (for example, infrared light or visible light modulated at high speed with a sine wave or rectangular wave), and is a device capable of high-speed modulation such as an LED. Is used.

  The imaging element 15 receives a plurality of photoelectric conversion elements (also referred to as pixels or pixels) that receive incident light 14 including reflected light that is irradiated from the light source 11 and reflected by an object in the target space, and converts the incident light 14 into charges. A plurality of charge storage units provided for each element (in this embodiment, four charge storage units C1, C2, C3, and C4 are illustrated. Hereinafter, C1, C2, C3, and C4 are the charge when used in the mathematical expression. Storage units C1, C2, C3, and C4), and means for distributing charges converted by the photoelectric conversion elements to a plurality of charge storage units in synchronization with the modulation of the light source 11. (Both not shown).

  The control unit 16 controls the light source 11 and the image sensor 15 synchronously. The image sensor 15 performs charge distribution based on the reference frequency fs. Specifically, as illustrated in FIG. 2, the image sensor 15 is synchronized with the reference frequency fs according to the gate control signals DG1, DG2, DG3, and DG4 supplied from the control unit 16, and T1, T2, T3, and T4. Each time, the gate is opened and closed, and the charges converted by the photoelectric conversion elements are distributed to the charge storage portions C1, C2, C3, and C4, respectively. The imaging element 15 acquires one image by repeating the cycle of time T1 to T4 several thousand to several hundred thousand times. This time for acquiring one image is called one frame. Note that the number of charge storage units is not limited to four. The present invention can be similarly applied to two or more charge storage portions.

The distance image generation unit 17 performs a predetermined calculation based on the charges distributed as described above (charges stored in the charge storage units C1, C2, C3, and C4), and generates a distance image whose pixel value is a distance value. Generate.
[Principle for generating range images]
Next, the principle of generating a distance image will be described.

  FIG. 3 is a diagram for explaining the principle of generating a distance image. In FIG. 3, a sine wave 21 represents light of the reference frequency fs emitted from the light source 11, and a sine wave 22 represents light incident on the image sensor 15. The phase difference φ between the sine wave 21 and the sine wave 22 represents a delay caused by the flight time to the object of the light of the reference frequency fs emitted from the light source 11.

  In FIG. 3, one cycle of the light emitted from the light source 11 is divided into four periods, and the charges are distributed to the four charge storage units C1, C2, C3, and C4. If each period is T1, T2, T3, and T4, and the amount of charge accumulated in each period is C1, C2, C3, and C4, the phase difference φ is expressed by the following equation.

光の速度は既知であるから、この位相差φを求めることで対象物までの距離が求まり、画素値が距離値である距離画像を生成することが可能となる。

Since the speed of light is known, the distance to the object can be obtained by obtaining this phase difference φ, and a distance image whose pixel value is a distance value can be generated.

  The charge amount average A used as general image data is expressed by the following equation.

また、対象物で反射した変調光成分の振幅量Ｂは、次の式で表される。

The amplitude amount B of the modulated light component reflected by the object is expressed by the following equation.

一般的に発光源の変調周波数は数十ＭＨｚであり、よって変調の１周期は数十ｎｓ程度である。そのため、距離画像を得るためには数百〜数十万周期の電荷蓄積時間を要する。
〔データ通信装置１の動作例１〕
次に、上記構成のデータ通信装置１の動作例１について図面を参照しながら説明する。

In general, the modulation frequency of the light source is several tens of MHz, and therefore one period of modulation is about several tens of ns. Therefore, in order to obtain a distance image, a charge accumulation time of several hundred to several hundred thousand cycles is required.
[Operation example 1 of the data communication apparatus 1]
Next, an operation example 1 of the data communication apparatus 1 configured as described above will be described with reference to the drawings.

  FIG. 4 is a flowchart for explaining an operation example 1 of the data communication apparatus 1. The following processing is mainly performed by the control unit 16 or a control unit (not shown) provided separately from the control unit 16.

  First, the data communication apparatus 1 performs a process of imaging the surrounding environment with the image sensor 15 (step S1). Specifically, the following processing is performed.

  The light source 11 irradiates the target space with light having the reference frequency fs under the control of the control unit 16. The imaging element 15 receives incident light including reflected light that is irradiated from the light source 11 and reflected by an object in the target space, converts the incident light into charges by a plurality of photoelectric conversion elements, and gate control signals DG1 from the control unit 16, According to DG2, DG3, and DG4, the converted charge is distributed to each of the plurality of charge storage units C1, C2, C3, and C4.

  The above processing is continued until the light accumulation time ends (elapses). By this processing, for example, as shown in FIG. 5, an image including the data transmission light sources 41, 42, and 43 is acquired.

  As shown in FIG. 5, the data transmission light sources 41 and 42 are provided in a traffic signal installed on the road, and the data transmission light source 43 is provided in an oncoming vehicle. FIG. 6 is a diagram illustrating light having a reference frequency fs whose phase is changed every predetermined time Tc. FIG. 7 is an enlarged view of a portion surrounded by a circle in FIG. As shown in FIGS. 6 and 7, the data transmission light sources 41, 42, and 43 are light sources similar to the light source 11, and the reference frequency fs whose phase is changed according to transmission information at each predetermined time Tc. The light is irradiated.

  In this way, by changing the phase of the light having the reference frequency fs in accordance with transmission information every predetermined time Tc, for example, the phase is divided into a plurality of phases as in phase shift modulation (Phase Shift Keying). Information can be assigned to each divided phase (embedding information), and information can be assigned to the amount of phase change (for example, φn−φn + 1 when the phase changes from φn → φn + 1) (information embedding) It becomes.

  It should be noted that how many phases can be divided and how much information can be embedded in the amount of phase change depends on the accuracy with which the phase is obtained. If the data transmission side and the reception side operate using the same clock, the phase can be obtained with high accuracy, and therefore the phase can be divided into a large number. However, in reality, since the data transmission side and the reception side operate using different clocks, even if modulation is performed at the reference frequency, a phase shift occurs gradually over time, and the number of phases that can be divided is small. Will decrease. However, since it is possible to assign multiple bits of information for each changed phase, it is possible to send and receive multiple bits of information (multiple bits of information assigned for each changed phase) at a time. Compared to this, faster data communication is possible.

  FIG. 8 is a graph showing the intensity of each of the irradiation lights 51, 52, and 53 from the data transmission light sources 41, 42, and 43 shown in FIG. Since the data transmission light sources 41, 42, and 43 have different intensities and distances, the received light intensity is different. In addition, since the synchronization is not performed, the phases of the irradiation lights 51, 52, and 53 are also different.

  Next, the data communication apparatus 1 uses data transmission light sources (for example, data transmission light sources 41 and 42 illustrated in FIG. 5) that emit light having a reference frequency fs from an image (for example, the image illustrated in FIG. 5) captured by the image sensor 15. 43) is extracted (steps S2 to S6). Specifically, the following processing is performed.

  First, charges are read from a plurality of charge storage units C1, C2, C3, and C4 (step S2), and the differences C1-C3 and C2-C4 of the charges are calculated by all image conversion elements (step S3). A pixel in which the differences C1-C3 and C2-C4 in the image captured by 15 exceed the threshold is determined (step S4: No, step S5). Then, from the image picked up by the image pickup device 15 (for example, the image shown in FIG. 5), the pixels determined to have the differences C1-C3 and C2-C4 exceed the threshold are set as data transmission light sources (for example, the data transmission light source 41 shown in FIG. 5). , 42, 43). On the other hand, the pixels for which the differences C1-C3 and C2-C4 are determined to be equal to or less than the threshold value are determined to be incident light from the background or an unmodulated light source (step S4: Yes, step S6).

  Since incident light from a background or an unmodulated light source has a uniform light intensity, differences C1-C3 and C2-C4 are applied to photoelectric conversion elements that receive incident light from the background or an unmodulated light source. The value of is a value equal to or less than the threshold (a value close to 0). On the other hand, for the photoelectric conversion elements that receive irradiation light from the data transmission light sources (for example, the data transmission light sources 41, 42, and 43), the values of the differences C1 to C3 and C2 to C4 exceed the threshold values. Accordingly, by comparing and calculating the values of the differences C1-C3 and C2-C4 and the threshold values in all the image conversion elements (step S4), pixels in which the difference in the image captured by the imaging element 15 exceeds the threshold value (that is, (Data transmission light source) can be determined.

  The processes in steps S2 to S6 described above are executed for all the photoelectric conversion elements. By this processing, it is possible to extract data transmission light sources (for example, data transmission light sources 41, 42, and 43 shown in FIG. 5) from an image (for example, an image shown in FIG. 5) captured by the imaging element 15.

  Next, the phase of the light of the reference frequency irradiated from the data transmission light source (for example, the data transmission light sources 41, 42, and 43 shown in FIG. 5) extracted by the processing of steps S2 to S6 is calculated using the above formula 1. Calculate (step S7).

  FIG. 9 shows the temporal change (φn−1 ′ → φn → φn → φn ′ → φn + 1 →) of the phase of the irradiation light from the data transmission light source (for example, the data transmission light source 41 shown in FIG. 5) calculated in step S7. (φn + 1 → φn + 1 ′ → φn + 2...)

  As shown in FIG. 9, the image sensor 15 has a time shorter than a predetermined time Tc (in FIG. 9, Tc (n−1), Tc (n), Tc (n + 1), Tc (n + 2)). An image is captured (step S1), and each time an image is captured, a data transmission light source (for example, data transmission light sources 41, 42, and 43 shown in FIG. 5) is extracted from the image (steps S2 to S6). The phase of the light of the reference frequency irradiated from is calculated (step S7). This time is called a frame rate Tf. The frame rate Tf is desirably equal to or less than ½ of a predetermined time Tc.

  As shown in FIG. 9, when the frame rate Tf includes the time points P1, P2, and P3 when the phase changes, the irradiation from the data transmission light source (for example, the data transmission light source 41 shown in FIG. 5) calculated in step S7. The phase of the light is different from the actual phase (phases indicated by φn−1 ′, φn ′, and φn + 1 ′ in FIG. 9). Alternatively, the phase cannot be calculated. For this reason, the data communication apparatus 1 deletes information on the frame rate Tf (phases indicated by φn−1 ′, φn ′, and φn + 1 ′ in FIG. 9).

  Next, a group of pixels whose phase differences calculated in step S7 are equal to or less than a threshold and adjacent to each other are determined as one data transmission light source (for example, the data transmission light source 41 shown in FIG. 5) and combined (step S8). The data transmission light source determined as the one data transmission light source is extracted, and an image including the data transmission light source extracted as the group of pixels is generated (step S9). FIG. 10 shows an example of the image generated in step S9 (including data transmission light sources 41, 42, and 43 determined and extracted as one data transmission light source).

  In this way, by determining and combining a group of pixels adjacent to each other as one data transmission light source, it is possible to prevent each individual photoelectric conversion element from being mistakenly regarded as one data transmission light source. Note that, as a pixel combination method, for example, it is conceivable to use the same pixel value (for example, a value representing the phase calculated in step S7) as a pixel value of a group of pixels.

  By using the image generated in step S9, it is possible to decode the transmission information from the data transmission light source without being affected by the background light. Further, data communication can be performed simultaneously with a plurality of data transmission light sources (for example, data transmission light sources 41, 42, and 43 shown in FIG. 5). Further, the number, position, size, distance, rotation, movement, phase, and the like of the data transmission light sources (for example, the data transmission light sources 41, 42, and 43 shown in FIG. 5) can be grasped. Further, the load for these processes is reduced, and it is possible to increase the speed and reduce the circuit scale.

  As described above, according to the data communication apparatus 1 of the present embodiment, the image sensor 15 uses the light of the reference frequency fs (the reference frequency fs whose phase is changed according to transmission information at predetermined time intervals). An image including a data transmission light source (for example, data transmission light sources 41, 42, and 43 shown in FIG. 5) that irradiates light (that is, light in which transmission information is embedded) is captured (step S1), and the captured image is A data transmission light source (for example, data transmission light sources 41, 42, and 43 shown in FIG. 5) is extracted (steps S2 to S6), and the phase of the light having the reference frequency fs emitted from the extracted data transmission light source is calculated ( In step S7), the transmission information from the data transmission light source is decoded based on the calculated phase.

For this reason, according to the data communication apparatus 1 of the present embodiment, in the data communication apparatus 1 that performs data communication using an image captured by the image sensor 15, information of a plurality of bits (for example, assigned for each changed phase) is assigned at a time. Multiple bits of information) can be transmitted and received, and data communication can be performed at a higher speed than in the past.
[Operation example 2 of the data communication apparatus 1]
Next, an operation example 2 of the data communication apparatus 1 configured as described above will be described with reference to the drawings.

  FIG. 11 is a flowchart for explaining an operation example 2 of the data communication apparatus 1. The following processing is mainly performed by the control unit 16 or a control unit (not shown) provided separately from the control unit 16.

  In this operation example 2, the data transmission light source (for example, the data transmission light source 41 shown in FIG. 5) includes a plurality of data transmission light sources 1001, 1002, and 1003 as shown in FIG. The plurality of data transmission light sources 1001, 1002, and 1003 are arranged in a predetermined positional relationship (in FIG. 12, an example in which three data transmission light sources are arranged on a straight line at equal intervals). In FIG. 12, the central data transmission light source 1001 irradiates light 1101 having a reference frequency fs as shown in FIG. 13, and the data transmission light sources 1002 and 1003 on both sides correspond to the light 1101 having the reference frequency fs. Then, the light 1002 and 1003 of the reference frequency fs whose phase (same phase) is changed according to the transmission information are irradiated.

  In this way, by changing the phase of the light 1002 and 1003 of the reference frequency fs according to the transmission information with respect to the light 1001 of the reference frequency fs, for example, the phase can be changed as in phase shift modulation (Phase Shift Keying). It is possible to divide into a plurality of pieces and assign information (embedding information) for each of the divided phases.

  First, the data communication apparatus 1 captures an image including the three data transmission light sources 1001, 1002, and 1003 by performing the processes of steps S1 to S9 shown in FIG. 4 (step S1), and from the captured images. The data transmission light sources 1001, 1002, and 1003 are extracted, an image including the extracted data transmission light sources 1001, 1002, and 1003 is generated (steps S2 to S9), and the data transmission light sources 1001 and 1002 are generated based on the images. , 1003, the phase of the irradiated light is calculated (step S10).

  Next, the data communication device 1 determines whether or not there are two or more data transmission light sources whose difference between the phases calculated in step S10 is equal to or less than a threshold (step S11).

  When there are two or more data transmission light sources whose phase difference calculated in step S10 is equal to or less than the threshold (step S11: Yes), the two data transmission light sources (in the example shown in FIG. 12, data transmission is used). Presence / absence of a data transmission light source having a predetermined positional relationship with respect to the light sources 1002 and 1003) (in the example shown in FIG. 12, whether or not the data transmission light source 1001 exists at the midpoint of the data transmission light sources 1002 and 1003) ) Is determined (step S12).

  When there is a data transmission light source (for example, data transmission light source 1001) having a predetermined positional relationship with respect to two data transmission light sources (for example, data transmission light sources 1002, 1003) (step S12: Yes), these three data The transmission light source (for example, the data transmission light source 1001, 1002, 1003) is determined as one data transmission light source (for example, the data transmission light source 41) (step S13), and for example, the phase of the irradiation light from the middle-point data transmission light source 1001 A phase difference with the phase of irradiation light from the data transmission light sources 1002 or 1003 at both ends is calculated, and transmission from the data transmission light source (for example, the data transmission light source 41 shown in FIG. 5) is performed based on the calculated phase difference. Information is decoded (step S14).

  As described above, according to the data communication device 1 of the present embodiment, the image sensor 15 captures an image including a data transmission light source (for example, the data transmission light source 1001, the data transmission light source 1002, and the data transmission light source 1003) ( Step S1), the data transmission light source (for example, the data transmission light source 1001, the data transmission light source 1002, and the data transmission light source 1003) is extracted from the captured image (Steps S2 to S6). A data transmission light source (for example, a data transmission light source) having a predetermined positional relationship with respect to the phase of light of a reference frequency emitted from a data transmission light source (for example, the data transmission light source 1002 and the data transmission light source 1003). 1001) to calculate the phase difference from the phase of the light of the reference frequency fs emitted (step S7). S13), based on the phase difference issued the calculated are configured to decode the transmitted information (step S14). When there are not two or more data transmission light sources whose phase difference calculated in step S10 is equal to or less than the threshold value (step S11: No), it is determined that there is no data transmission light source (for example, data transmission light source 41) ( Step S15).

  For this reason, according to the data communication device 1 of the present embodiment, in a data communication device that performs data communication using an image captured by an image sensor, a plurality of bits of information (a plurality of bits allocated for each changed phase) Information) can be transmitted and received, and data communication can be performed at a higher speed than in the past. In addition, according to the data communication device 1 of the present embodiment, the phase of the light of the reference frequency fs emitted from the data transmission light source 1001 that is in a predetermined positional relationship with respect to the two data transmission light sources 1002 and 1003. A phase difference is calculated, and transmission information is decoded based on the calculated phase difference. For this reason, it is possible to prevent or reduce the calculation of the phase difference from the erroneous data transmission light source (that is, decoding error).

  In the present embodiment, an example using three data transmission light sources 1001, 1002, and 1003 has been described, but the present invention is not limited to this. For example, two data communication light sources 1001 and 1002 may be used.

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

It is a block diagram of the data communication apparatus of this embodiment. FIG. 10 is a diagram for explaining charge distribution in the image sensor 15. It is a figure for demonstrating the principle which produces | generates a distance image. 3 is a flowchart for explaining an operation example 1 of the data communication apparatus 1; It is an example of an image including the data transmission light source imaged by the image sensor. It is a figure showing the light of the reference frequency fs which changed the phase for every predetermined time Tc. FIG. 7 is an enlarged view of a portion surrounded by a circle in FIG. 6. It is the graph which showed each intensity | strength of irradiation light 51,52,53 from the data transmission light sources 41,42,43 shown in FIG. It is a figure showing the time change ((phi) n-1 '-> φn-> φn-> φn'-> φn + 1-> φn + 1-> φn + 1 '-> φn + 2 ...) of the phase of irradiation light from a data transmission light source. It is an example of an image including data transmission light sources 41, 42, and 43 determined as one data transmission light source and extracted. 6 is a flowchart for explaining an operation example 2 of the data communication apparatus 1; 6 is a perspective view for explaining an example of a data transmission light source used in an operation example 2 of the data communication apparatus 1. FIG. 13 is a graph showing the intensity of each irradiation light from data transmission light sources 1001, 1002, and 1003 shown in FIG. It is a figure for demonstrating the method of performing data communication using the image imaged with the conventional image pick-up element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Distance image generation apparatus, 10 ... Light time-of-flight type distance image sensor (distance image sensor), 11 ... Light source, 14 ... Incident light, 15 ... Image sensor, 16 ... Control part, 17 ... Distance image generation part, 41, 42, 43 ... data transmission light source, 1001, 1002, 1003 ... data transmission light source, φ ... phase

Claims (8)

In a data communication device that performs data communication using an image captured by an image sensor,
Based on a plurality of photoelectric conversion elements that receive incident light and convert them into charges, a plurality of charge storage units provided for each of the photoelectric conversion elements, and a reference frequency, the charges converted by the photoelectric conversion elements An image sensor provided with a means for distributing to a plurality of charge storage units;
Extraction means for extracting a data transmission light source that emits light of a reference frequency from an image captured by the image sensor;
Phase calculating means for calculating the phase of the light of the reference frequency irradiated from the data transmission light source extracted by the extracting means;
Decoding means for decoding transmission information based on the phase calculated by the phase calculation means;
A data transmission device comprising: A determination unit that calculates a difference between charges accumulated in the plurality of charge accumulation units, and that determines a pixel in which the difference in the image captured by the image sensor exceeds a threshold;
The data communication apparatus according to claim 1, wherein the extraction unit extracts a pixel determined by the determination unit as a data communication light source from an image captured by the image sensor.   The phase calculation unit calculates a phase of light having a reference frequency emitted from the data transmission light source extracted by the extraction unit, based on charges accumulated in the plurality of charge accumulation units. Item 3. A data transmission device according to item 1 or 2.   The determination unit includes a group of pixels whose phase calculated by the calculation unit is equal to or less than a threshold value among pixels in which the difference in the image captured by the image sensor exceeds a threshold value and that is adjacent to each other, as one data transmission light source. The data communication device according to claim 2, wherein the data communication device is determined.   5. The data transmission device according to claim 1, further comprising an image generation unit configured to generate an image including the data transmission light source extracted by the extraction unit.   6. The data communication apparatus according to claim 1, wherein the data transmission light source irradiates light having a reference frequency whose phase is changed according to transmission information every predetermined time. The data transmission light source includes a first data transmission light source and a second data transmission light source,
The first data transmission light source emits light of a reference frequency,
The second data transmission light source irradiates light of a reference frequency whose phase is changed according to transmission information with respect to light of the reference frequency emitted from the first data transmission light source,
The phase calculating means calculates the phase of the reference frequency light emitted from the first data transmission light source, the phase of the reference frequency light emitted from the second data transmission light source, and the phase difference between these phases. Calculate
6. The data communication apparatus according to claim 1, wherein the decoding unit decodes the transmission information based on the phase difference calculated by the phase calculation unit. The data transmission light source includes a first data transmission light source, a second data transmission light source, and a third data transmission light source arranged in a predetermined positional relationship,
The first data transmission light source emits light of a reference frequency,
The second data transmission light source and the third data transmission light source irradiate light of a reference frequency whose phase is changed according to transmission information with respect to light of the reference frequency emitted from the first data transmission light source,
The phase calculating means is configured to emit a reference frequency light emitted from the first data transmission light source, a reference frequency light phase emitted from the second data transmission light source, and a third data transmission light source. The phase of the light of the reference frequency, the phase of the light of the reference frequency irradiated from the two data transmission light sources whose phase difference between the phases is equal to or less than the threshold value, and the positional relationship predetermined for the two data transmission light sources Calculate the phase difference with the phase of the light of the reference frequency irradiated from the data transmission light source,
6. The data transmission apparatus according to claim 1, wherein the decoding unit decodes the transmission information based on a phase difference between phases calculated by the phase calculation unit.

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