JP5917456B2 - Sign information output device - Google Patents

Description

  The present invention relates to a sign information output device that detects a sign around a road based on an image pickup signal from an image pickup unit and outputs sign information relating to the type of the sign.

  2. Description of the Related Art Conventionally, there is known an apparatus that detects a sign around a road based on an image signal from an image pickup unit and outputs sign information related to the type of the sign. In particular, since this type of device sequentially captures images while the vehicle is running, the scene around the vehicle can change from moment to moment. Therefore, it is preferable that this apparatus executes control so that the output content of the marker information at the present time completely follows the change of the scene. Alternatively, instead of this, control may be performed so that previous contents different from the sign information existing in the current scene are not output as erroneous sign information.

  For example, Patent Document 1 proposes a method of gradually hiding sign information (aging status) based on a traveling state including at least one of a traveling distance, an elapsed time, and a vehicle speed.

US Patent Application Publication No. 2012/0046855

  By the way, due to various circumstances including legal, geographical reasons, and living environment, the installation interval of the signs arranged along the road is different for each area (particularly the country). For this reason, when the method proposed in Patent Document 1 is used, when traveling on a road with a large interval between signs, the sign information is hidden before reaching the next sign. In some cases, the vehicle occupant feels uncomfortable.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sign information output device capable of stopping the output of sign information in a timely manner regardless of the area in which the vehicle travels. .

  A sign information output device according to the present invention is mounted on a vehicle, acquires an imaging signal by imaging while the vehicle is traveling, and a road from an image area represented by the imaging signal acquired by the imaging unit. A sign detection unit that detects signs in the vicinity of the vehicle, an information output unit that outputs sign information related to the type of the sign detected by the sign detection unit, and the travel distance of the vehicle is measured using the detection of the sign as a trigger The same type as the travel instruction measuring unit, and the output instruction unit instructing the information output unit to stop outputting the marker information when the travel distance measured by the travel distance measuring unit exceeds a threshold value. A threshold value changing unit that changes the threshold value according to at least one of interval information related to an installation interval of the sign, speed limit information related to a speed limit of the road, and a speed of the vehicle. Obtain.

  Thus, when the travel distance measured with the detection of the sign exceeds the threshold, the output instruction unit that instructs the information output unit to stop outputting the sign information, and the installation of the sign that is the same type Since there is provided a threshold value changing unit that changes the threshold value according to at least one of the interval information about the interval, the speed limit information about the speed limit of the road, and the speed of the vehicle, the sign setting interval, the speed limit of the road In consideration of at least one of the vehicle speed and the vehicle speed, it is possible to set a maximum travel distance (that is, a threshold) at which the sign information can be continuously output. Thereby, the output of the sign information can be stopped in a timely manner regardless of the difference in the area where the vehicle travels.

  In addition, the travel distance measurement unit measures the travel distance from the most recently detected sign to the next sign detected to be the same type, and the threshold change unit is used as the interval information. It is preferable to change the threshold according to the travel distance. By taking into account the installation interval actually measured while the vehicle is running, the timeliness when stopping the output of the sign information is further enhanced.

  In addition, the learning unit further includes a storage unit that sequentially stores the measured travel distance, and the threshold value changing unit receives a plurality of the travel distances stored most recently by the storage unit and outputs the threshold value. It is preferable to change based on. Thereby, an appropriate threshold value based on the latest measurement result can be obtained.

  Moreover, it is preferable that the said threshold value change part changes the said threshold value according to the kind of the said road as the said speed limit information. By taking into account the tendency that the sign installation interval varies depending on the type of road, timeliness when stopping the output of sign information is further enhanced.

  The sign detection unit further detects whether the road type is a general road or a highway based on the numerical value of the speed limit indicated by the sign, and the threshold value changing unit It is preferable to change the threshold value by selecting one of the corresponding first threshold value and the second threshold value corresponding to the expressway. Thereby, the threshold suitable for a general road or a highway can be selected by using the numerical value (that is, the speed limit) indicated by the sign as a clue.

  The threshold value changing unit changes the threshold value by selecting a third threshold value different from the first threshold value and the second threshold value when the road type determination unit cannot determine the road type. It is preferable to do. For example, when the speed unit system is different, it may not be possible to determine which of the speed limits the general road or expressway corresponds to. In this case, it is possible to cope with various numerical ranges and various unit systems by assigning a third threshold different from the first threshold and the second threshold. In addition, since the number of thresholds to be retained is sufficient, the amount of data to be stored can be reduced.

  Moreover, it is preferable that the said threshold value change part changes the said threshold value according to the jurisdiction area of the said road as the said speed limit information. By taking the road jurisdiction further into account, the timeliness when stopping the output of sign information is further enhanced.

  Moreover, it is preferable that the said memory | storage part does not memorize | store the said travel distance, when the numerical value of the said speed limit which two adjacent said signs show differs. There are cases where signs indicating different numerical values are mixed on the same road. In general, the calculation accuracy of the learning process can be maintained by excluding the measurement result in the case where the numerical values are different in consideration of the periodicity in the arrangement relationship between the signs indicating the same numerical values.

  Moreover, it is preferable that the said memory | storage part does not memorize | store the said travel distance, when the advancing direction of the said vehicle changes during the measurement of the said travel distance. Since there is a high possibility that a lane change will occur when the traveling direction of the vehicle changes, the calculation accuracy of the learning process can be maintained by excluding this measurement result in advance.

  According to the sign information output device according to the present invention, when the travel distance measured using the sign detection as a trigger exceeds a threshold, the output instruction unit that instructs the information output unit to stop outputting the sign information; Since there is provided a threshold value changing unit that changes the threshold value according to at least one of the interval information related to the installation interval of the signs of the same type, the speed limit information related to the speed limit of the road, and the speed of the vehicle. In consideration of at least one of the installation interval, road speed limit, and vehicle speed, it is possible to set a maximum travel distance (that is, a threshold) at which the sign information can be continuously output. Thereby, the output of the sign information can be stopped in a timely manner regardless of the difference in the area where the vehicle travels.

It is an electric block diagram which shows the structure of the label | marker information output device which concerns on this embodiment. 2A is an interior view of the vehicle incorporating the sign information output device shown in FIG. 1 as viewed from the driver side. 2B is a schematic front view of the display unit shown in FIG. 2A. It is a schematic explanatory drawing regarding the output operation | movement of the label | marker information output device shown in FIG. It is a flowchart with which operation | movement description of the label | marker information output device shown in FIG. 1 is provided. It is a schematic explanatory drawing regarding the data structure of the space | interval table shown in FIG. It is the 1st explanatory view about the change method of a threshold. It is the 2nd explanatory view about the change method of a threshold. It is a 3rd explanatory drawing regarding the change method of a threshold value.

  Hereinafter, preferred embodiments of a sign information output device according to the present invention will be described in detail with reference to the accompanying drawings.

[Overall Configuration of Sign Information Output Device 10]
FIG. 1 is an electric block diagram showing a configuration of a sign information output device 10 according to this embodiment.

  As shown in FIG. 1, the sign information output device 10 includes a camera 12 (imaging unit) that images the periphery of a vehicle 50 (FIG. 2A and the like), a speed sensor 14 that detects the speed of the vehicle 50, and a yaw rate of the vehicle 50. The yaw rate sensor 16 for detecting the steering angle, the steering angle sensor 18 for detecting the steering angle of the vehicle 50, the GPS (Global Positioning System) sensor 20 for detecting the current position of the vehicle 50, and the sign information output device 10 are controlled. ECU 22 (Electronic Control Unit; electronic speaker unit) which performs, the speaker 24 which outputs an audio | voice, and the display part 26 which outputs visible information are provided.

  The ECU 22 is a computer composed of a microcomputer or the like. In this embodiment, the ECU 22 functions as the input / output unit 28, the calculation unit 30, and the storage unit 32.

  Various signals from the camera 12, the speed sensor 14, the yaw rate sensor 16, the steering angle sensor 18, and the GPS sensor 20 are input to the ECU 22 side via the input / output unit 28. Various signals from the ECU 22 are output to the speaker 24 and the display unit 26 via the input / output unit 28. The input / output unit 28 includes an A / D conversion circuit (not shown) that converts an input analog signal into a digital signal.

  The calculation unit 30 performs calculations based on various signals input via the input / output unit 28 and generates control signals for the speaker 24 and the display unit 26 based on the calculation results. The calculation unit 30 functions as a sign detection unit 34, a travel distance measurement unit 36, a threshold change unit 38, and an output instruction unit 40.

  The function of each unit in the calculation unit 30 is realized by reading and executing a program stored in the storage unit 32. Alternatively, the program may be supplied from the outside via a wireless communication device (mobile phone, smartphone, etc.) not shown.

  The storage unit 32 includes an imaging signal converted into a digital signal, a RAM (Random Access Memory) that stores temporary data used for various arithmetic processes, and a ROM (Read Only) that stores an execution program, a table, a map, or the like. Memory) and the like. In this example, an interval table 42 and speed limit data 44 described later are stored.

  Here, the speaker 24 and the display unit 26 correspond to an information output unit 46 that outputs sign information regarding the type of the detected sign. The information output unit 46 can output, for example, information signs that can be reported to the human senses, including images (still images / moving images), characters, or sounds.

  FIG. 2A is an interior view of the vehicle 50 incorporating the sign information output device 10 shown in FIG. 1 as viewed from the driver side. 2B is a schematic front view of the display unit 26 shown in FIG. 2A. The vehicle 50 shows a situation where the vehicle is traveling on a road in a country where it is determined that the vehicle is traveling on the left side, and the vehicle 50 is illustrated as a right-hand drive vehicle.

  As shown in FIG. 2A, the camera 12 is disposed in the vicinity of the rearview mirror 52 in the vehicle interior of the vehicle 50, and passes through the front windshield 54 to the surrounding area of the vehicle 50 (in this example, a road 56 and a sign 58. Image). For example, the camera 12 is a digital video camera, and can capture an image every predetermined frame clock interval (for example, 30 frames per second).

  The dashboard 60 is provided with a handle 64 that protrudes from the lower part toward the driver's seat 62. At a position aligned with the center position of the handle 64 (for example, in the instrument panel 66), an MID (Multi-Information Display) as the display unit 26 is disposed. As a result, the driver can view the display unit 26 with the face facing forward of the vehicle 50. The general-purpose display 68 is disposed at a predetermined portion of the dashboard 60 (specifically, a portion on the left side with respect to the position where the display unit 26 is disposed). Instead of MID, a general-purpose display 68 may be used as the display unit 26.

  As shown in FIG. 2B, the display unit 26 is provided with a rectangular display region 70 that is long in the horizontal direction. In the right half of the display area 70, sign information 72 simulating the mark 58 is displayed. In addition to the at least one type of sign information 72, the display unit 26 can display fuel consumption, current time, information on the instrument panel 66, and the like.

[Description of Operation of Sign Information Output Device 10]
The sign information output device 10 according to this embodiment is basically configured as described above. Hereinafter, an output process of the sign information output apparatus 10 will be schematically described with reference to FIG. In this specification, the process of outputting the marker information 72 and the process of stopping the output are collectively referred to as “output process”.

  As shown in FIG. 3, it is assumed that a vehicle 50 travels on a road 56 having a speed limit of 50 [kph]. The vehicle 50 passes through a sign 58 around the road 56 while going straight from the left side to the right side of the drawing. When the sign 58 exists far ahead of the vehicle 50, no information is output in the display area 70 because the sign 58 is not detected by the sign information output device 10.

  Thereafter, when the vehicle 50 reaches the vicinity of the sign 58, the sign information output device 10 (particularly the ECU 22) detects the presence and type of the sign 58, and detects the sign information corresponding to the type of the sign 58 with respect to the display unit 26. 72 output is instructed. An occupant of the vehicle 50 can grasp at a glance that the speed limit of the currently traveling road 56 is 50 [kph] by visually recognizing the output content of the display unit 26.

  Thereafter, when the vehicle 50 travels a specific distance (for example, the threshold value Lth) without detecting the presence of another sign, the ECU 22 instructs the display unit 26 to stop outputting the sign information 72. As a result, the sign information 72 displayed in the display area 70 is erased.

[Detailed description regarding output processing of sign information 72]
Next, the output process of the sign information 72 in the sign information output apparatus 10 will be described in detail with reference mainly to the flowchart of FIG.

  In step S1, the ECU 22 acquires speed limit data 44 as information on the speed limit of the vehicle 50 (hereinafter, speed limit information). Prior to this acquisition, the GPS sensor 20 acquires the current position of the vehicle 50 based on the received GPS signal. And ECU22 acquires the speed limit data 44 corresponding to a present position by reading the map data which is not illustrated from the memory | storage part 32, and referring to it.

  The speed limit data 44 includes, for example, not only the speed limit (value and unit system) of the road 56 but also the jurisdiction (country, state, district) of the road 56 corresponding to the speed limit metadata, and the type of the road 56 ( General road or highway).

  The map data includes route calculation data used for calculating a recommended route, route guidance data used for guiding the vehicle 50 to a destination according to the recommended route, such as an intersection name and a road name, and road shape. Road data to be represented, and background data representing map shapes other than roads, such as coastlines, rivers, railroads, and buildings, are included.

  In step S <b> 2, the ECU 22 acquires an imaging signal in front of the vehicle 50 (predetermined angle of view range) for each frame and temporarily stores it in the storage unit 32. For example, when an RGB camera is used as the camera 12, the obtained imaging signal represents a multi-gradation image composed of three color channels.

  In step S <b> 3, the sign detection unit 34 detects the sign 58 around the road 56 from the image area represented by the imaging signal. As this detection process, various known image recognition processes (specifically, template matching methods, etc.) suitable for the type of sign 58 can be applied. The types of signs 58 that can be detected include guide signs (such as “directions / directions”), warning signs (such as “decrease in number of lanes”), regulatory signs (such as “maximum speed”), and instruction signs (such as “pedestrian crossings”). Or an auxiliary sign (such as “vehicle type”). In addition, the sign detection unit 34 further detects whether the type of the road 56 is a general road or a highway by extracting a numerical value indicated by the sign 58 for the sign 58 having a specific shape. May be.

  In step S4, the ECU 22 determines whether or not at least one marker 58 has been detected in step S3. When it is determined that “no detection” (step S4: NO), the process returns to step S2, and steps S2 and S3 are sequentially repeated. On the other hand, when it is determined that “there is detection” (step S4: YES), the process proceeds to the next step (S5).

  In step S <b> 5, the travel distance measurement unit 36 checks the value of a flag (hereinafter referred to as “continuation flag”) for determining whether or not the measurement of the travel distance L is continued. Since it is set to “OFF” in the initial state (step S5: OFF), the process proceeds to the next step (S6).

  In step S <b> 6, the travel distance measurement unit 36 starts measuring the travel distance L of the vehicle 50 using the detection of the sign 58 as a trigger. The travel distance measuring unit 36 may measure the speed of the vehicle 50 obtained from the speed sensor 14 by integrating it with time, or may measure by tracking the position of the vehicle 50 via the GPS sensor 20. . Note that the timing of starting the measurement is not limited to the time when the sign 58 is detected for the first time, and may be arbitrarily set such as the time when the vehicle 50 reaches the sign 58.

  In step S <b> 7, the threshold value changing unit 38 sets a threshold value Lth that is used for an output stop instruction for the sign information 72. A specific method for setting the threshold value Lth will be described later.

  In step S <b> 8, the output instruction unit 40 instructs the display unit 26 to output the marker information 72. By this instruction, sign information 72 (see FIG. 2B and the like) related to the kind of sign 58 is newly displayed in the display area 70 of the display unit 26.

  In step S9, the ECU 22 sequentially executes an imaging operation and a detection operation, similarly to steps S2 and S3.

  In step S <b> 10, the sign detection unit 34 determines whether a next sign that is different from the sign 58 and of the same type (hereinafter simply referred to as “next sign 58”) has been detected. When it is determined that “no detection” (step S10: NO), the output instruction unit 40 compares the magnitude relationship between the travel distance L being measured starting from step S6 and the threshold value Lth set in step S7. (Step S11).

  When the relationship of L> Lth is not satisfied (step S11: NO), in other words, when the relationship of L ≦ Lth is satisfied, the process returns to step S8, and thereafter steps S8 and S9 are sequentially repeated. On the other hand, when the relationship of L> Lth is satisfied (step S11: YES), the process proceeds to the next step (S12).

  In step S12, the output instruction unit 40 instructs the display unit 26 to stop outputting the label information 72. By this instruction, the sign information 72 displayed in the display area 70 is erased.

  In step S13, the arithmetic unit 30 changes the continuation flag from “OFF” to “ON”. Here, it should be noted that the measurement of the travel distance L is continued even after the output of the sign information 72 is stopped.

  Thereafter, returning to step S2, the ECU 22 sequentially repeats steps S2 and S3 until the next sign 58 is detected. Thereafter, when the next sign 58 is detected (step S4: YES), the travel distance measuring unit 36 confirms that the continuation flag is “ON” (step S5: ON), and the next step (S14). Proceed to

  In step S14, the arithmetic unit 30 changes the continuation flag from “ON” to “OFF”. Thereafter, in step S <b> 15, the travel distance measurement unit 36 ends the measurement of the travel distance L and temporarily stores the travel distance L obtained by the measurement in the storage unit 32.

  In step S <b> 16, the calculation unit 30 updates the travel distance L obtained in step S <b> 15 as one stored value in the interval table 42 under a predetermined update condition.

  Thereafter, returning to step S6, the travel distance measuring unit 36 sequentially executes steps S6 to S11. Thus, the sign information output device 10 performs the output process of the sign information 72 by sequentially executing steps S1 to S16 of FIG. 4 while the vehicle 50 is traveling.

[Static change method of threshold Lth]
Next, a specific example of a method for statically changing the threshold value Lth by the threshold value changing unit 38 will be described. Prior to setting / changing the threshold value Lth, the threshold value changing unit 38 selectively reads one of the plurality of types of interval tables 42 from the storage unit 32.

  FIG. 5 is a schematic explanatory diagram relating to the data structure of the interval table 42 shown in FIG. In this example, three types of tables having the same data format, specifically, “first table”, “second table”, and “third table” are prepared. Each table is associated with a numerical value of the speed limit indicated by the sign 58 (hereinafter also referred to as a sign value) or the type of the road 56 on which the vehicle 50 travels.

  The first table is used when the marking value is in the range of “0 to 40” or the type of the road 56 is “general road”. In all the first to fifth stored values, “150” (unit: m) is stored as an initial state.

  The second table is used when the marking value is within the range of “70 or more” or the type of the road 56 is “highway”. In all the first to fifth stored values, “1000” (unit: m) is stored as an initial state.

  By the way, as a unit system of speed, kilometers per hour (kph) are mainly used in France, while miles per hour (mph) are mainly used in the UK. Usually, only the numerical value (for example, “50”) of the speed limit is written on the indicator 58, and the unit system associated with the indicator value is omitted. For this reason, it may not be possible to determine which speed limit corresponds to the general road or the highway depending on the range of the marking value. Therefore, considering that the speed unit system varies depending on the jurisdiction of the road 56, another table that can be shared by both general roads and highways is further prepared.

  The third table is used when the marking value is in the range of “41 to 69” or the type of the road 56 is “general road (kph) or highway (mph)”. In all the first to fifth storage values, “250” (unit: m) is stored as an initial state.

  Here, the threshold value changing unit 38 selectively reads out the first to third tables according to the speed limit data 44 or the speed of the vehicle 50, and sets the value as the threshold value Lth. Hereinafter, specific examples (first to fifth examples) will be described in detail.

<First example>
The threshold changing unit 38 may set / change the threshold Lth according to the jurisdiction of the road 56 as the speed limit data 44. Taking the jurisdiction of the road 56 into account further increases the timeliness when stopping the output of the sign information 72.

  Specifically, when the jurisdiction is “country A”, the value of the first table (Lth = 150 [m]), and when the jurisdiction is “country B”, the value of the third table (Lth = 250 [m]). ]). Thereafter, the threshold value changing unit 38 multiplies the read value (for example, 250) by a margin coefficient (a positive number equal to or greater than 1; for example, 1.2) to obtain 250 [m] × 1.2 = 300. [M] is obtained. Thereafter, the threshold value changing unit 38 sets the numerical value “300” obtained as the threshold value Lth and supplies it to the output instruction unit 40 side.

<Second example>
The threshold value changing unit 38 may set / change the threshold value Lth according to the label value of the sign 58 as the speed limit data 44. The threshold value changing unit 38 selects and acquires a table corresponding to the label value obtained by the detection process in the sign detection unit 34 from a plurality of types of tables. Here, in the example of FIG. 3, since the label value is “50”, the third table is read.

<Third example>
The threshold value changing unit 38 may set / change the threshold value Lth according to the type of the road 56 as the speed limit data 44. By taking into account the tendency that the installation interval of the sign 58 differs depending on the type of the road 56, the timeliness when stopping the output of the sign information 72 is further enhanced.

  Specifically, the threshold value changing unit 38 has a first threshold value (150 [m] × 1.2 = 180 [m]) corresponding to a general road and a second threshold value (1000 [m] × 1) corresponding to a highway. .2 = 1200 [m]) may be selected / changed. Thereby, the threshold value Lth suitable for a general road or a highway can be selected by using the number (that is, the numerical value of the speed limit) indicated by the sign 58 as a clue.

<Fourth example>
If the type of the road 56 cannot be determined by the sign detection unit 34 or the like, the threshold value changing unit 38 selects and changes a third threshold value (300 [m]) different from the first threshold value and the second threshold value. Also good. As a result, it is possible to cope with various numerical ranges and various unit systems, and the number of thresholds to be held is three, so that the amount of data to be stored can be reduced.

<Fifth example>
The threshold value changing unit 38 may set / change the threshold value Lth according to the speed of the vehicle 50. This is because the speed of the vehicle 50 is highly correlated with the speed limit of the road 56 on which the vehicle 50 travels. Specifically, the threshold value changing unit 38 estimates the speed limit of the road 56 based on the time series of the speed of the vehicle 50 sequentially detected by the speed sensor 14, and then creates a table in the same manner as in <Second Example>. You may choose. Alternatively, the interval table 42 itself may be associated with the speed of the vehicle 50.

  Thus, the threshold value changing unit 38 may set / change the threshold value Lth according to the speed limit data 44 or the speed of the vehicle 50. This method is particularly effective in jurisdictions where the interval between the signs 58 is substantially constant.

[Dynamic Changing Method of Threshold Lth]
Next, a dynamic changing method of the threshold value Lth by the threshold changing unit 38 will be described in detail with reference to FIGS.

  As described above, in the jurisdiction where the installation interval of the sign 58 is constant, it is preferable to statically change the threshold value Lth (typical value of the installation interval). However, the setting method described above may not be suitable for roads 56 where the interval between the signs 58 is significantly different. Specifically, it is assumed that the installation interval or the sign form of the sign 58 is suddenly switched while traveling on a road 56 that straddles different jurisdictions such as countries, regions, and areas.

  Therefore, in this embodiment, in addition to or separately from the above-mentioned “static change”, the threshold value Lth is set to “dynamic” based on information (hereinafter referred to as interval information) regarding the installation interval of the same type of sign 58. Adopt a method to change. The interval information includes not only the travel distance L from when the sign 58 is detected until the next sign 58 is detected, but also a measured value based on the imaging signal from the camera 12 and a measured value based on the GPS signal from the GPS sensor 20. It is.

  As shown in FIG. 6, it is assumed that a vehicle 50 travels on a road 56 having a speed limit of 50 [kph]. The vehicle 50 passes through the signs 58a, 58b, and 58c in the vicinity of the road 56 in order while going straight in the range from the position P1 to the position P5. On the left side in the traveling direction of the road 56, signs 58a, 58b, and 58c each having a marking value “50” (unit: kph) are installed. It is assumed that the interval between the signs 58a and 58b is 500 [m], and the interval between the signs 58b and 58c is 300 [m].

  At the position P1, among the three types of interval tables 42, the third table (label values 41 to 69) in which all the first to fifth stored values are “250” is selected. In the section from the position P1 to the position P2, since none of the signs 58a to 58c is detected, the output state of the display unit 26 is always “OFF (non-display state)”. Further, the interval table 42 remains in the initial state, and the threshold value Lth has not been set yet.

  It is assumed that the first sign 58a is detected for the first time at the position P2. In this case, the output state of the display unit 26 is changed from “OFF” to “ON (display state)”, and the threshold value Lth is set to Lth = 1.2 × (250 + 250 + 250 + 250 + 250) / 5 = 300 [m]. The Here, the threshold value changing unit 38 multiplies the average value (one form of statistical value) among the five stored values by a margin coefficient (a positive number equal to or greater than 1; for example, 1.2) to set the threshold value Lth. Note the points to be calculated.

  Since the travel distance L starting from the position P2 reaches Lth = 300 [m] at the position P3, the output state of the display unit 26 is changed from “ON” to “OFF”. Thereafter, the measurement of the travel distance L is continued even after passing through the position P3.

  It is assumed that the second sign 58b is detected for the first time at the position P4. In this case, the output state of the display unit 26 is changed from “OFF” to “ON (display state)”. Then, the travel distance L = 500 [m] as the measurement result is stored in a first-in first-out (FIFO) format in the interval table 42 (first stored value; rectangular thick frame). Further, the threshold value Lth is changed to Lth = 1.2 × (500 + 250 + 250 + 250 + 250) / 5 = 360 [m].

  It is assumed that the third marker 58c is detected for the first time at the position P5. In this case, the output state of the display unit 26 is maintained “ON”. The travel distance L = 300 [m] as the measurement result is stored in the FIFO table in the interval table 42 (first stored value; rectangular thick frame). Further, the threshold value Lth is changed to Lth = 1.2 × (300 + 500 + 250 + 250 + 250) / 5 = 372 [m].

  As described above, the travel distance measurement unit 36 measures the travel distance L from the most recently detected sign 58a (or sign 58b) to the sign 58b (or sign 58c) that is detected next as being of the same type. To do. The threshold value changing unit 38 changes the threshold value Lth according to the travel distance L as the interval information. By taking into account the installation interval actually measured while the vehicle 50 is traveling, the timeliness when stopping the output of the sign information 72 is further enhanced.

  Further, the storage unit 32 sequentially stores the measured travel distance L. Then, the threshold value changing unit 38 changes the threshold value Lth based on a learning process in which the most recently stored travel distances L are input and the threshold value Lth is output. Thereby, an appropriate threshold value Lth based on the latest measurement result is obtained. Note that the learning processing algorithm is not limited to statistical processing including averaging, and various types of machine learning employing any one of supervised learning, unsupervised learning, and reinforcement learning can be applied. Examples of the learning architecture include a boosting method including AdaBoost, a support vector machine (SVM), a neural network, an EM (Expectation Maximization) algorithm, and the like.

  By the way, in FIG. 6, although the case where the space | interval table 42 is updated whenever the driving | running | working distance L is measured is illustrated, the process different from this is employable.

<First example>
As shown in FIG. 7, it is assumed that a vehicle 50 travels on a road 56 having a speed limit of 50 [kph]. However, it differs from FIG. 6 in that a sign 58d with a sign value “60” is specifically installed instead of the sign 58b with a sign value “50”. “ON1” in the output state of the display unit 26 indicates the on state of the sign information 72 related to “50”, and “ON2” indicates the on state of the sign information 72 related to “60”.

  At this time, the same processing as in the case of FIG. 6 is executed between the position P1 and the position P3. When the second sign 58d is detected for the first time at the position P4, the travel distance L = 500 [m] is measured as the installation interval between the signs 58a and 58d.

  Here, the storage unit 32 stores the travel distance L when the numerical values of the speed limits indicated by the two adjacent signs 58a and 58d are the same, but does not store the travel distance L when they are different. In the example of FIG. 7, since “60” of the sign 58d detected this time is different from “50” of the sign 58a detected last time, the travel distance L = 500 [m] is not stored. The value of Lth is maintained as Lth = 300 [m].

  When the third sign 58c is detected for the first time at the position P5, the travel distance L = 300 [m] is measured as the installation interval between the signs 58d and 58c. However, since “50” of the sign 58c detected this time is different from “60” of the sign 58d detected last time, the value of the threshold Lth is stored without storing the travel distance L = 300 [m]. Is maintained at Lth = 300 [m].

  As described above, the signs 58a to 58c and 58d for indicating different numerical values on the same road 56 may be mixed. In general, the calculation accuracy of the learning process can be maintained by excluding the measurement results when the numerical values are different in consideration of the periodicity in the arrangement relationship between the signs 58a to 58c indicating the same numerical values.

<Second example>
As shown in FIG. 8, it is assumed that the vehicle 50 travels on a road 56 having a speed limit of 50 [kph]. However, the road 56 differs from FIG. 6 in that it has an L-shaped curve 56c. The vehicle 50 sequentially passes a sign 58e in front of the curve 56c and a sign 58f in the back of the curve 56c.

  Here, the ECU 22 executes known determination processing based on various signals from the camera 12, the yaw rate sensor 16, and the like, and detects a change in the traveling direction of the vehicle 50. Then, when the traveling direction of the vehicle 50 changes during measurement of the travel distance L, the storage unit 32 travels the travel distance L regardless of the coincidence of the speed limit values indicated by the two adjacent signs 58e and 58f. Do not remember. Since there is a high possibility of lane change when the traveling direction of the vehicle 50 changes, the calculation accuracy of the learning process can be maintained by excluding this measurement result in advance.

[Effects of sign information output device 10]
As described above, the sign information output device 10 according to this embodiment is mounted on the vehicle 50, and is obtained from the camera 12 that acquires an imaging signal by imaging while the vehicle 50 is traveling, and the image area represented by the imaging signal. The sign detection unit 34 for detecting the sign 58 around the road 56, the information output unit 46 for outputting the sign information 72 regarding the type of the sign 58, and the travel distance L of the vehicle 50 are measured using the detection of the sign 58 as a trigger. The distance between the travel distance measuring section 36, the output instruction section 40 that instructs the information output section 46 to stop outputting the sign information 72 when the travel distance L exceeds the threshold Lth, and the installation interval of the signs 58 of the same type. A threshold value changing unit 38 that changes the threshold value Lth according to at least one of the speed information of the road 56, the speed limit information about the speed limit of the road 56, and the speed of the vehicle 50.

  Since it is configured in this manner, the maximum travel capable of continuously outputting the sign information 72 in consideration of at least one of the installation interval of the sign 58, the speed limit of the road 56, and the speed of the vehicle 50. The distance (that is, the threshold value Lth) can be set. Thereby, the output of the sign information 72 can be stopped in a timely manner regardless of the difference in the area where the vehicle 50 travels.

[Supplement]
In addition, this invention is not limited to embodiment mentioned above, Of course, it can change freely in the range which does not deviate from the main point of this invention.

  In this embodiment, the above-described output processing is performed on the imaging signal obtained by the monocular camera (camera 12), but it goes without saying that the same effect can also be obtained by a compound eye camera (stereo camera).

  2A and 2B of this embodiment exemplify a form in which the sign information 72 is output in a fixed and temporary manner. However, an effect that deforms the sign information 72 over time (for example, a fade-out effect). May be given.

DESCRIPTION OF SYMBOLS 10 ... Sign information output device 12 ... Camera 22 ... ECU 24 ... Speaker 26 ... Display part 30 ... Calculation part 32 ... Memory | storage part 34 ... Sign detection part 36 ... Traveling distance measurement part 38 ... Threshold change part 40 ... Output instruction | indication part 42 ... Interval table 44 ... Speed limit data 46 ... Information output unit 50 ... Vehicle 56 ... Road 58 (af) ... Sign 72 ... Sign information

Claims (7)

An imaging unit that is mounted on a vehicle and acquires an imaging signal by imaging while the vehicle is running;
A sign detection unit that detects signs around a road from an image region represented by the imaging signal acquired by the imaging unit;
An information output unit that outputs label information related to the type of the label detected by the label detection unit;
A mileage measuring unit that measures the mileage of the vehicle using the detection of the sign as a trigger;
An output instruction unit that instructs the information output unit to stop outputting the sign information when the travel distance measured by the travel distance measurement unit exceeds a threshold;
And a threshold changing unit for changing the threshold depending on the distance information about the installation interval of the labels of the same type,
The travel distance measuring unit measures the travel distance from the most recently detected sign to the next detected sign of the same type,
The said threshold value change part changes the said threshold value according to the said travel distance as said space | interval information, The label | marker information output device characterized by the above-mentioned . In the sign information output device according to claim 1 ,
A storage unit that sequentially stores the measured travel distance;
The said threshold value change part is changed based on the learning process which uses the said some driving distance memorize | stored most recently by the said memory | storage part as an input, and outputs the said threshold value. The marker information output device characterized by the above-mentioned. An imaging unit that is mounted on a vehicle and acquires an imaging signal by imaging while the vehicle is running;
A sign detection unit that detects signs around a road from an image region represented by the imaging signal acquired by the imaging unit;
An information output unit that outputs label information related to the type of the label detected by the label detection unit;
A mileage measuring unit that measures the mileage of the vehicle using the detection of the sign as a trigger;
An output instruction unit that instructs the information output unit to stop outputting the sign information when the travel distance measured by the travel distance measurement unit exceeds a threshold;
A threshold value changing unit that changes the threshold value according to speed limit information related to the speed limit of the road;
With
The sign detection unit further detects whether the road type is a general road or a highway based on the numerical value of the speed limit indicated by the sign,
The threshold value changing unit includes a first threshold value corresponding to the general road among the road types as the speed limit information and a second value corresponding to the highway among the road types as the speed limit information . The sign information output device, wherein the threshold value is changed by selecting one of the threshold values. In the sign information output device according to claim 3 ,
The threshold value changing unit may change the threshold value by selecting a third threshold value different from the first threshold value and the second threshold value when the type of the road cannot be determined by the sign detection unit. Characteristic sign information output device. In the sign information output device according to claim 2 ,
The storage unit, if the value of two of the labels adjacent shown to limit speeds are different, label information output apparatus characterized by not storing the travel distance. In the sign information output device according to claim 2 ,
The said memory | storage part does not memorize | store the said travel distance when the advancing direction of the said vehicle changes during the measurement of the said travel distance, The sign information output apparatus characterized by the above-mentioned. An imaging unit that is mounted on a vehicle and acquires an imaging signal by imaging while the vehicle is running;
A sign detection unit that detects signs around a road from an image region represented by the imaging signal acquired by the imaging unit;
An information output unit that outputs label information related to the type of the label detected by the label detection unit;
A mileage measuring unit that measures the mileage of the vehicle using the detection of the sign as a trigger;
An output instruction unit that instructs the information output unit to stop outputting the sign information when the travel distance measured by the travel distance measurement unit exceeds a threshold;
A threshold value changing unit that changes the threshold value according to the speed of the vehicle ,
The sign detection unit further detects whether the road type is a general road or a highway based on the speed of the vehicle,
The said threshold value change part changes the said threshold value by selecting any one among the 1st threshold value corresponding to the said general road, and the 2nd threshold value corresponding to the said expressway, The sign information output apparatus characterized by the above-mentioned .

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