KR102006626B1 - Apparatus and method for generating a signal for extending the traffic signal for protecting a pedestrian in crosswalk - Google Patents

Abstract

The present invention relates to an apparatus and method for generating a traffic signal extension signal, comprising: a camera for acquiring an image of a pedestrian crossing and a sidewalk and a roadway adjacent thereto; And a pedestrian recognition area setting unit for setting a pedestrian recognition area based on the outermost lane area adjacent to the sidewalk area and the crosswalk area, and the presence of a pedestrian in the pedestrian recognition area. By measuring the crossing / recognition unit for recognizing whether or not, the traffic light recognition unit for recognizing the color of the signal currently lit on the pedestrian traffic light of the crosswalk, and the pre-stored timer to measure the lighting / blinking time for each signal of the pedestrian traffic light Signal system information generation unit for generating signal system information adjacent to the crosswalk, and green light of the pedestrian traffic light When the pedestrian is present in the crossing area to be character recognized destroy point, it characterized in that it comprises a generator for generating a signal to the lighting time is extended signal such as the green group so as to extend by adding the time set.
Accordingly, when the pedestrian's moving position is close to the center of the crosswalk at the time when the green light of the crosswalk flashes, the lighting time of the green light is extended by an additional time based on the pedestrian's walking speed so that the pedestrian can safely cross the crosswalk. When the pedestrian's moving position is the outermost lane adjacent to the sidewalk, the green light of the pedestrian crossing may be flickered as it is, thereby preventing unnecessary traffic jams from occurring.

Description

Apparatus and method for generating traffic signal extension signal for pedestrian protection for crosswalks {APPARATUS AND METHOD FOR GENERATING A SIGNAL FOR EXTENDING THE TRAFFIC SIGNAL FOR PROTECTING A PEDESTRIAN IN CROSSWALK}

The present invention relates to a traffic signal extension signal generating device and method for generating an extension signal for further extending the lighting time of the crosswalk green light according to the moving position of the pedestrians walking the crosswalk.

In general, a traffic light means a device that displays a progress, wait or stop signal to secure traffic safety and smooth traffic flow in a railroad or a road. In particular, where two or more roads, such as an intersection, need to organically control traffic lights in each direction, the traffic lights are controlled through a program to switch the signal according to a predetermined rule.

Among them, pedestrian crossing traffic lights give pedestrians and vehicles the right of way, thereby reducing the incidence of traffic accidents by suppressing conflicts between pedestrians and vehicles, and reducing the waiting time of pedestrians and congestion rates. It is installed and used.

However, the conventional pedestrian crossing traffic light has a structure that simply outputs the lighting / flashing state according to the preset lighting / flashing cycle, so that pedestrians who enter the pedestrian crossing late run quickly to cross the pedestrian crossing before the green light blinks. Cases frequently occur, and traffic accidents with vehicles that do not recognize pedestrians who have jumped into the crosswalk suddenly occur frequently.

In particular, when the pedestrians including the disabled, pregnant women, the injured and the elderly who have lower walking speed than the general people use the conventional pedestrian crossing traffic lights, the conventional pedestrian crossing traffic lights turn on before the pedestrians complete the pedestrian crossing. Traffic accidents of pedestrians are frequently occurring by blinking green lights along the flashing cycle.

That is, since the conventional pedestrian crossing traffic light is not configured to protect the pedestrians at all, the pedestrians were forced to walk the pedestrian crossing under threat of life. In addition, as the number of multi-lane roads increases due to the increase of vehicles, the risk of pedestrian crossing crossings is increasing.

KR 10-2015-0114621 A KR 10-1433649 B1

An object of the present invention is to solve the above problems, according to the movement position of the pedestrians walking pedestrian crossing to further extend the lighting time of the pedestrian crossing green light to generate a traffic signal extension signal for pedestrians walking safely crosswalk It is an object to provide an apparatus and method.

An apparatus for generating a traffic signal extension signal according to an aspect of the present invention for achieving the above object includes a camera for acquiring an image of a crosswalk and a sidewalk and a roadway adjacent thereto, and a sidewalk, a crosswalk, and a lane from the image. An area recognition unit for recognizing and separately distinguishing areas corresponding to each other, a crosser recognition area setting unit for setting a crosser recognition area based on the outermost lane area adjacent to the sidewalk area and the crosswalk area, and the crosser Cross section recognition unit for recognizing the presence of a pedestrian in the recognition area, a signal light recognition unit for recognizing the color of the signal currently turned on the pedestrian traffic light of the crosswalk, and by using a pre-stored timer lights for each signal of the pedestrian traffic light A signal system information generator for generating signal system information adjacent to the crosswalk by measuring / flashing time; And a signal generation unit configured to generate an extension signal for extending the lighting time of the green light by a predetermined additional time when the pedestrian is present in the traversing area when the green light of the own traffic light blinks. It is done.

Preferably, the transversal recognition area setting unit detects a pair of outermost lane areas adjacent to the sidewalk area at positions symmetric with respect to the center of the crosswalk area and the crosswalk area, respectively, In the crosswalk area, an area overlapping with the area surrounded by the pair of outermost lane areas may be set as the crosswalk recognition area.

Preferably, a traverse for extracting the pedestrian's walking speed according to the change amount of the edge component by extracting an edge component of the pedestrian located in the traversal recognition region from the image and then calculating a walking completion time of the pedestrian based on the image. Characterized in that it further comprises a child vector calculation unit.

Preferably, the signal generation unit generates an extension signal extending the lighting time of the green light by an additional time based on a difference between the calculated walking completion time and the remaining time until the green light blinks. It is done.

In addition, according to another aspect of the present invention, there is provided a method for generating a traffic signal extension signal, the method comprising: acquiring an image of a pedestrian crossing, a sidewalk and a roadway adjacent thereto; Classifying and recognizing the crossover, setting a crosswalk recognition area based on the outermost lane area adjacent to the sidewalk area and the crosswalk area, and recognizing the color of the signal currently lit by the pedestrian traffic light of the crosswalk. And generating signal system information adjacent to the pedestrian crossing by measuring lighting / flashing time points of signals of the pedestrian traffic light using a pre-stored timer, and when the green light of the pedestrian traffic light blinks. When the pedestrian is present in the recognition area, the lighting time of the green light may be extended by a predetermined additional time. And generating an extension signal to lock.

Preferably, the setting of the pedestrian crossing area may include detecting a pair of outermost lane areas adjacent to the sidewalk area at positions symmetric with respect to the center of the crosswalk area and the crosswalk area. Subsequently, an area overlapping an area surrounded by the pair of outermost lane areas in the crosswalk area may be set as the crosswalk recognition area.

Preferably, between the step of generating the signal system information and the step of generating the extension signal, recognizing the presence or absence of a pedestrian in the cross-sectional recognition area, and if the pedestrian is present, from the image And calculating a walking speed of the pedestrian based on the pedestrian's walking speed according to the change amount of the edge component by extracting an edge component of the pedestrian located in the traversal recognition region. do.

Preferably, the generating of the extension signal comprises: extending an extension signal for extending the lighting time of the green light by an additional time based on a difference between the calculated walking completion time and the remaining time until the green light blinks. It is characterized by generating.

According to the present invention, when the pedestrian's moving position is close to the center of the crosswalk at the time when the green light of the crosswalk blinks, it is not easy to walk by avoiding a large number of vehicles that are driving, so the pedestrian may not be caught on the driveway. As such, the lighting time of the green light is extended by an additional time based on the walking speed of the pedestrian, so that the pedestrian can safely walk the crosswalk.

Further, according to the present invention, when the pedestrian's moving position is the outermost lane adjacent to the sidewalk at the time when the green light of the crosswalk blinks, the pedestrian can reach the sidewalk sufficiently by a short distance corresponding to one side of the road. In addition, the crosswalk green light is flickering as it is to prevent unnecessary traffic jams.

1 is a conceptual diagram of a traffic signal extension signal generating apparatus according to an embodiment of the present invention,
2 is a block diagram of a traffic signal extension signal generating apparatus according to an embodiment of the present invention,
3 is a flowchart illustrating a method for generating a traffic signal extension signal according to an embodiment of the present invention.

Specific matters including the problem to be solved, the solution to the problem, and the effects of the present invention as described above are included in the following embodiments and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

1 is a conceptual diagram of a traffic signal extension signal generating apparatus according to an embodiment of the present invention, Figure 2 is a block diagram of a traffic signal extension signal generating apparatus according to an embodiment of the present invention.

1 and 2, the traffic signal extension signal generating apparatus 100 according to an embodiment of the present invention is largely the camera 110, the area recognition unit 120, the traversal recognition area setting unit 130, The traversal recognition unit 140, the traffic light recognition unit 150, the signal system information generating unit 160 and the signal generating unit 170 is configured to include.

The camera 110 acquires an image of a predetermined crosswalk 20, a sidewalk 10 adjacent thereto, and a roadway.

In this case, the camera 110 may be fixedly installed at a position adjacent to the vehicle traffic light at a position substantially spaced apart from the ground so that the crosswalk, the sidewalk 10 and the driveway area are included together in the frame screen.

The area recognizer 120 distinguishes and recognizes areas corresponding to the sidewalk 10, the crosswalk, and the lane from the image acquired through the camera 110.

In detail, as illustrated in FIG. 2, the area recognizer 120 includes a delivery area recognizer 121, a lane recognizer 122, and a crosswalk recognizer 123.

Here, the delivery area recognition unit 121 and the crosswalk recognition unit 123 assign respective coordinate values to the delivery area and the crosswalk area of the photographing area of the camera 110 at a fixed position according to a preset coordinate system. In addition, the closed area corresponding to the coordinate value is divided into the delivery area 10 and the crosswalk area 20 from each frame of the image acquired by the camera 110 in real time.

Here, the lane recognizing unit 122 recognizes this as a lane area when a straight edge area that is spaced apart in parallel at a predetermined interval is extracted from a predetermined frame of the image acquired by the camera 110.

The pedestrian recognition area setting unit 130 sets the pedestrian recognition area 40 based on the outermost lane area 30 and the crosswalk area 20 adjacent to the sidewalk 10 area.

In detail, as illustrated in FIG. 1, the transverse recognition area setting unit 130 may have the delivery area 10 located at a position symmetrical with respect to the exact center of the crosswalk area 20 and the crosswalk area 20. After detecting a pair of outermost lane areas adjacent to each other, an area that overlaps the area surrounded by the pair of outermost lane areas in the crosswalk area 20 may be set as the traversal recognition area 40.

Traffic signal extension signal generating apparatus 100 according to an embodiment of the present invention includes the area recognition unit 120 according to the above configuration, regardless of the length of the crosswalk, the number of lanes or the width of the lane crossing recognition This has the advantage that the area 40 can be set automatically.

The tramper recognition unit 140 recognizes whether a pedestrian is present in the tramper recognition area 40.

Here, the traversal recognition unit 140 recognizes that the pedestrian is present when the edge component of the pedestrian located in the traversal recognition area 40 is extracted from the image acquired through the camera 110, otherwise, It is recognized that a pedestrian does not exist.

In this case, the edge component may detect an outline of a pedestrian by using a general edge detection algorithm such as a second derivative using a Laplacian operation. Since such edge detection algorithm is obvious to those skilled in the art, a separate description will be omitted.

The traffic light recognition unit 150 recognizes the color of the signal currently turned on by the pedestrian traffic light 1 of the crosswalk.

Here, the traffic light recognition unit 150 is configured to detect a signal state by installing a sensor that can detect a light on the front of the green lamp of the pedestrian traffic light (1) to detect only whether the green signal is lit or the pedestrian traffic light (1 You can also install a light sensor on both the green and red lamps to detect both signals at the same time.

The signal system information generation unit 160 generates signal system information adjacent to the crosswalk by measuring a lighting / flashing time for each traffic signal of the pedestrian traffic light using a pre-stored timer.

At this time, the timer is pre-stored in the signal system information generating unit 160, and the green signal is received from the traffic light recognition unit 150 in real time by receiving information on the color of the traffic signal currently turned on in the pedestrian traffic light (1) After measuring the time point at which the and red signals are turned on or blinking, signal system information is generated, which is a database of measured data over a predetermined time.

When the pedestrian is present in the traverse recognition area when the green light of the pedestrian traffic light 1 blinks, the signal generator 170 extends the lighting time of the green light by a predetermined additional time. Create

On the other hand, the traffic signal extension signal generating apparatus 100 according to an embodiment of the present invention, the walking completion time based on the walking speed of the pedestrian located in the traverse recognition area 40 from the image acquired through the camera 110 It may further include a traversal vector calculation unit 180 to calculate the.

Here, the crossing vector calculator 180 extracts an edge component of the pedestrian located in the cross recognizer 40 from the image acquired through the camera 110, and thus the walking speed of the pedestrian according to the change amount of the edge component. After calculating the calculated walking completion time of the pedestrian based on this.

For example, at a straight line distance between a center point of an edge component extracted from an image frame captured at a first point of time through the camera 110 and a center point of an edge component extracted from an image frame captured at a second point after the first point in time. The moving distance of the corresponding pedestrian is calculated and the moving time of the pedestrian corresponding to the time difference between the first frame and the second frame is calculated in consideration of the image acquisition speed, that is, the number of frames per second of the camera 110. Afterwards, the walking speed of the pedestrian can be finally obtained.

In this case, the edge component may be detected using a general edge detection algorithm as described above in the transverse recognition unit 140.

In this case, the signal generator 170 turns on the green light by an additional time based on the difference between the walking completion time calculated by the traversal vector calculation unit 180 and the remaining time until the green light flashes. An extension signal can be generated to extend the time.

For example, referring to FIG. 2, in the state where the signal generation unit 170 receives the signal system information from the signal system information generation unit 160 in real time, the traversal vector calculation unit 2 seconds before the walking signal ends. When the walking completion time calculated by 180 is 3.8 seconds, an extension signal is generated to extend the lighting time of the green light by an additional time of '1.8 seconds' corresponding to the difference between '3.8 seconds' and '2 seconds'. Done.

3 is a flowchart illustrating a method for generating a traffic signal extension signal according to an embodiment of the present invention.

Hereinafter, a traffic signal extension signal generation method according to an embodiment of the present invention will be described with reference to the above-described drawings.

First, an image obtained by photographing a crosswalk 20, a sidewalk 10 and a roadway adjacent thereto using the camera 110 is obtained (S100).

In this case, the camera 110 may be fixedly installed at a position adjacent to the vehicle traffic light at a position substantially spaced apart from the ground so that the crosswalk, the sidewalk 10 and the driveway area are included together in the frame screen.

Next, areas corresponding to sidewalks, crosswalks and lanes are separately recognized from the image acquired in step S100 (S200).

In detail, in operation S200, the coordinates of the delivery area and the pedestrian crossing area of the photographing area of the camera 110 at the fixed position are assigned to each coordinate value according to a preset coordinate system, and then obtained in real time by the camera 110. The closed area corresponding to the coordinate value is divided into the delivery area 10 and the crosswalk area 20 from each frame of the image, and parallelly spaced at predetermined intervals from a predetermined frame of the image acquired by the camera 110. When the straight edges spaced apart are extracted, this is recognized as a lane area.

Next, the crossing section recognition area is set based on the outermost lane area and the crosswalk area 20 adjacent to the delivery area 10 recognized in step S200 (S300).

Here, in step S300, as shown in FIG. 1, the pair of outermost lanes adjacent to the sidewalk area 10 at positions symmetrical with respect to the center of the crosswalk area 20 and the crosswalk area 20. After detecting the areas 30, the area that overlaps the area surrounded by the pair of outermost lane areas 30 in the crosswalk area 20 may be set as the cross recognizer area 40.

Next, after recognizing the color of the signal that is currently turned on the pedestrian traffic light (1) of the crosswalk, by using a pre-stored timer to measure the lighting / blinking time for each traffic signal of the pedestrian traffic light signal system information adjacent to the crosswalk To generate (S400).

Here, in step S400, by installing a sensor that can detect the light on the front of the green lamp of the pedestrian traffic light (1) configured to grasp the signal state to detect only whether the green signal is lit, or the green of the pedestrian traffic light (1) By installing a light detection sensor on both the lamp and the red lamp side to detect both signals at the same time, the color of the signal currently lit on the pedestrian traffic light (1).

In operation S400, information about a color of a signal that is currently turned on is obtained every real time. After measuring a time point at which the green signal and the red signal are turned on or blinking using a predetermined timer, the measured data is measured over a predetermined time. Generates the signaling system information that is made into a database.

Next, when the pedestrian is present in the crossing recognition area at the time when the green light of the pedestrian traffic light 1 blinks (S500), an extension signal for extending the lighting time of the green light by a predetermined additional time is provided. It generates (S600).

On the other hand, the traffic signal extension signal generation method according to an embodiment of the present invention, between the step S400 and S500, the step of recognizing the presence of the pedestrian in the traversal recognition area 40, and the pedestrian is present In this case, the edge component of the pedestrian located in the traversal recognition area 40 is extracted from the image acquired in step S100 to calculate the walking speed of the pedestrian according to the change amount of the edge component, and then the walking completion time of the pedestrian based on this. It may further comprise the step of calculating.

Here, in the step of recognizing the presence of the pedestrian, if the edge component of the pedestrian located in the traversal recognition area 40 is extracted from the image acquired in step S100, it is recognized that the pedestrian exists. It is recognized that a pedestrian does not exist.

In this case, the edge component may detect an outline of a pedestrian by using a general edge detection algorithm such as a second derivative using a Laplacian operation. Since such edge detection algorithm is obvious to those skilled in the art, a separate description will be omitted.

The step of calculating the walking completion time may include extracting an edge component of a pedestrian located in the traversal recognition area 40 from an image acquired through the camera 110, and walking of the pedestrian according to a change amount of the edge component. After the speed is calculated, the walking completion time of the pedestrian is calculated based on the speed.

For example, at a straight line distance between a center point of an edge component extracted from an image frame captured at a first point of time through the camera 110 and a center point of an edge component extracted from an image frame captured at a second point after the first point in time. The moving distance of the corresponding pedestrian is calculated and the moving time of the pedestrian corresponding to the time difference between the first frame and the second frame is calculated in consideration of the image acquisition speed, that is, the number of frames per second of the camera 110. Afterwards, the walking speed of the pedestrian can be finally obtained.

In this case, in step S600, an extension signal for extending the lighting time of the green light is generated by an additional time based on the difference between the calculated walking completion time and the remaining time until the green light blinks (S700).

For example, referring to FIG. 2, in the state in which signal system information is received from the signal system information generation unit 160 in real time, the walking calculated in the step of calculating the walking completion time 2 seconds before the walking signal is terminated. When the completion time is 3.8 seconds, an extension signal is generated to extend the lighting time of the green light by an additional time of '1.8 seconds' corresponding to the difference between '3.8 seconds' and '2 seconds'.

Accordingly, according to the present invention, when the pedestrian's moving position is close to the center of the crosswalk at the time when the green light of the crosswalk blinks, it is not easy to walk by avoiding a large number of vehicles that are driving, so that the pedestrian cannot be caught on the roadway. Since the possibility is large, the lighting time of the green light is extended by an additional time based on the walking speed of the pedestrian, so that the pedestrian can safely walk the crosswalk.

According to the present invention, when the pedestrian's moving position is the outermost lane adjacent to the sidewalk at the time when the green light of the crosswalk blinks, the pedestrian can reach the sidewalk sufficiently by a short distance corresponding to one side of the road. In addition, the crosswalk green light is flickering as it is to prevent unnecessary traffic jams.

As mentioned above, the present invention has been described in detail through preferred embodiments, but the present invention is not limited thereto and may be variously implemented within the scope of the claims.

In particular, the foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the claims of the invention that follow may be better understood, and thus, the concept and specific embodiments of the present invention described above serve to accomplish the same purpose as the present invention. It should be recognized by those skilled in the art that it can be used immediately as a basis for designing or modifying other shapes.

In addition, the embodiment described above is just one embodiment according to the present invention, it can be implemented in various modifications and changes in the scope of the technical idea of the present invention by those skilled in the art. I can understand. Accordingly, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation, and such various modifications and changes are also within the scope of the spirit and scope of the present invention as set forth in the claims. All differences should be interpreted as being included in the present invention.

1: pedestrian traffic light 10: sidewalk
20: crosswalk area 30: outermost lane area
40: cross section recognition area 100: traffic signal extension signal generating device
110: camera 120: area recognition unit
121: delivery area recognition unit 122: lane recognition unit
123: Crosswalk recognition unit 130: Crosser recognition area setting unit
140: traverse recognition unit 150: traffic light recognition unit
160: signal system information generation unit 170: signal generation unit
180: traverse vector generator

Claims (8)

A camera for acquiring images of pedestrian crossings and sidewalks and roadways adjacent thereto;
An area recognition unit for recognizing and distinguishing areas corresponding to sidewalks, crosswalks, and lanes from the image;
A pedestrian recognition area setting unit for setting a pedestrian recognition area based on the outermost lane area adjacent to the sidewalk area and the crosswalk area;
A pedestrian recognition unit for recognizing the presence or absence of a pedestrian in the pedestrian recognition area;
A traffic light recognition unit recognizing a color of a signal currently lit on the pedestrian traffic light of the crosswalk;
A signal system information generation unit configured to generate signal system information adjacent to the crosswalk by measuring a lighting or blinking time of each signal of the pedestrian traffic light using a pre-stored timer;
A signal generator for generating an extension signal for extending the lighting time of the green light by a predetermined additional time when the pedestrian is present in the traversing area when the green light of the pedestrian traffic light blinks; And
Cross section vector calculation unit for calculating the walking speed of the pedestrian according to the change amount of the edge component by extracting the edge component of the pedestrian located in the cross section recognition area from the image, and then calculate the completion time of walking of the pedestrian ; Including,
The area recognition unit,
A lane recognizing unit recognizing this as a lane area when a straight edge area that is spaced apart in parallel at a predetermined interval is extracted from a predetermined frame of the image acquired by the camera; More,
The traversal recognition area setting unit,
After detecting a pair of outermost lane areas adjacent to the sidewalk area at positions symmetrical with respect to the crosswalk area and the center of the crosswalk area, the pair of outermost lane areas in the crosswalk area The area overlapping with the area surrounded by is set as the traversal recognition area,
The signal system information generation unit,
After the timer is stored therein, after receiving the information on the color of the traffic signal currently turned on in the pedestrian traffic light from the traffic light recognition unit in real time and measuring the time point at which the green signal and the red signal are turned on or flashing, respectively, An apparatus for generating a signal extension signal for traffic, characterized in that for generating signal system information obtained by databaseting data measured over a predetermined time. delete delete The method of claim 1,
The signal generator,
And generating an extension signal for extending the lighting time of the green light by an additional time based on a difference between the calculated walking completion time and the remaining time until the green light flashes. Obtaining an image of a crosswalk and sidewalks and roadways adjacent thereto;
Distinguishing and recognizing regions corresponding to sidewalks, crosswalks, and lanes from the image;
Setting a pedestrian recognition area based on the outermost lane area adjacent to the sidewalk area and the crosswalk area;
Recognizing a color of a signal currently lit by the pedestrian traffic light of the crosswalk;
Generating signal system information adjacent to the pedestrian crossing by measuring a lighting or blinking time of each signal of the pedestrian traffic light using a pre-stored timer;
Recognizing the presence or absence of a pedestrian in the traversal recognition area;
When the pedestrian is present, the edge component of the pedestrian located in the traversal recognition area is extracted from the image to calculate the walking speed of the pedestrian according to the change amount of the edge component, and then the walking completion time of the pedestrian based on the image is calculated. Calculating; And
Generating an extension signal for extending the lighting time of the green light by a predetermined additional time when the pedestrian is present in the traversing area when the green light of the pedestrian traffic light blinks; Including,
Recognizing the area by distinguishing it,
Recognizing it as a lane area when a straight edge region, which is spaced apart in parallel at a predetermined interval, is extracted from a predetermined frame of the image acquired by the acquiring image; More,
The setting of the traverser recognition area may include:
After detecting a pair of outermost lane areas adjacent to the sidewalk area at positions symmetrical with respect to the crosswalk area and the center of the crosswalk area, the pair of outermost lane areas in the crosswalk area The area overlapping with the area surrounded by is set as the traversal recognition area,
Generating the signal system information,
Signal system information obtained by acquiring information on the color of the signal that is currently turned on in real time and measuring the time point at which the green signal and the red signal are turned on or blinking using a predetermined timer, and then database the measured data over a predetermined time period. Traffic signal extension signal generation method, characterized in that for generating. delete delete The method of claim 5,
Generating the extension signal,
And generating an extension signal for extending the lighting time of the green light by an additional time based on a difference between the calculated walking completion time and the remaining time until the green light blinks.

Images