JPH0525156B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention measures the number of moving objects passing through a monitoring surface, for example, the number of people entering and exiting a building, etc. using a storage type photodetector such as a CCD sensor. The present invention relates to a moving body amount measuring device that displays a moving body amount.

(Prior Art) Conventionally, devices for automatically measuring the number of people entering and exiting a building, etc. have been equipped with, for example, a photoelectric switch device that uses a light beam, a device that uses images from a television camera, or a switch built into a floor mat. A device using a so-called pine sensor is known. (Problems to be solved by the invention) However, in the case of the light beam method, it is not possible to distinguish when multiple people pass side by side, and in the case of the television camera method, it is impossible to distinguish when multiple people pass by from the camera image. The technology for pattern recognition of human images is complicated and the equipment is expensive, and the matt sensor has problems with durability because detection is based on mechanical switch operation.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned conventional problems, and it is possible to accurately determine the number of passing moving objects, for example, the number of people, and the device configuration is simple and cost-effective. The purpose is to provide an inexpensive moving body mass measuring device. At least two accumulation-type photodetectors each having a plurality of linear light-receiving pixels arranged perpendicularly to the moving direction of the moving body to monitor changes in brightness on a monitoring surface, and the accumulation-type photodetector using only the monitoring surface. background reference data storage means for storing light reception data obtained from the detector as background reference data; and background reference data storage means for storing light reception data obtained from the storage type photodetector when a moving object passes through a monitoring surface. a background processing means for subtracting the received light information from the background reference data stored in the background processing means; a memory means for storing received light information obtained by the background processing means; and a memory means for reading the received light information stored in the memory means at predetermined time intervals; The present invention is characterized by comprising arithmetic processing means for determining the moving direction of the moving objects and determining the number of moving objects based on the light reception information.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention.

First, to explain the configuration, 1 and 2 are charge-coupled devices (hereinafter referred to as "CCD sensors") as storage type photodetectors, and as shown in FIG. 2, a plurality of light receiving pixels 3a to 3n are linearly arranged. With this structure, when light hits each light-receiving pixel, it is possible to obtain an accumulated charge proportional to the integral amount of incident light over a certain accumulation time (exposure time) determined by the readout timing.

Regarding the CCD sensors 1 and 2 having such a structure, in the present invention, all received light data is not used as data used for calculation processing of traffic volume based on received light data, and the shaded area in Fig. 2 is used. As shown, for example, every fourth received light data A1, A5,...
An-1, B2, B6, . . . Bn are read out from the memory storing the light reception data by designation of the jumping address, and arithmetic processing is executed.

To explain one example more specifically, for example
As the CCD sensors 1 and 2, 2048 light-receiving pixels arranged in a straight line are used, and the light-receiving data of every 16 pixels is read out and data processing is performed. Here, CCD
Assuming that the monitoring length on the monitoring surface for each light-receiving pixel connected to the sensor is 0.25 cm, reading the light-receiving data every 16 pixels means reading the light-receiving data every 4 cm from the memory on the monitoring surface. It means to perform data processing.

By processing the light reception data read out at regular intervals among the light reception data obtained from the light reception pixels arranged in a straight line in this way, high-speed data processing is possible even when the number of pixels per line is large. becomes possible.

Note that the density of the light reception data used for data processing corresponding to the light reception pixels is determined within the range where the passing of a person can be detected, for example, when the moving object is a person, and is variable within the range where the person can be detected. I can do it.

The detection optical system of the present invention using these two CCD sensors is shown in FIG.

In FIG. 3, for example, if a person is passing by as a moving object to be detected, two monitoring lines A and B are formed as a monitoring surface on a floor surface 4 such as the entrance of a building.
For example, white lines are drawn parallel to the top to make it easier to detect changes in brightness due to the passage of a person, and the images of these monitoring lines A and B are reflected from the upper surface by the reflecting mirror 5 in the direction of movement in which the person passes. Condensing lens 6
The image of the monitoring line A is reflected from the condensing lens 6 to the half mirror 7 to form an image on the CCD sensor 1, while the image of the monitoring line B is transmitted from the condensing lens 6 to the half mirror 7. hand
Focus the image on CCD sensor 2. With such an optical system, the monitoring lines A and B are connected to the CCD sensor 1,
For example, a 0.25 cm image is reduced and formed on a line for each light-receiving pixel in 2.

FIG. 4 is a plan view showing the monitoring lines A and B in FIG. 3. In this embodiment, as an example, monitoring line A is drawn on the outside of the building, and monitoring line B is drawn on the inside of the building. The distance D between the monitoring lines A and B drawn in parallel here is determined by the size of the moving object; for example, if the moving object is a person, D=10.
It is set to about cm. Further, the width W of the monitoring lines A and B is determined by the size of the entrance/exit.

The reason why the distance D between the monitoring lines A and B is set to about 10 cm when the moving object is a person is as follows.

First, the shoulder width H1 of the person to be measured is statistically about 40 cm, as shown by the two-dot chain line, and the variance thereof is 20 to 60 cm. Also, the thickness of the chest
H2 is distributed in the range of H2 = 10 to 24 cm. Therefore, in order to determine the amount of traffic by detecting the change in brightness when passing through the two monitoring lines A and B, it is necessary to obtain a measurable probability close to 100% based on the chest thickness H2. Find the line spacing D = 9.64cm
Therefore, in practice, it is sufficient to set D = around 10 cm.

Next, the accumulation time of the CCD sensors 1 and 2 shown in FIG.
Since it is 2.19m/s, line spacing D = 9.64cm
When this happens, the line passing time is 44ms. If this amount of accumulation time can be secured, even when a person passes by, photoelectric charges can be sufficiently accumulated due to changes in the brightness of the monitoring line, and the CCD sensor, which functions as an accumulation-type photodetector, can detect the person's passing.

Note that since monitoring lines A and B are drawn, for example, as white lines, the line image incident on the CCD sensor is at maximum brightness in normal monitoring conditions when no person passes, and the brightness of the monitoring line decreases when a person passes. The passage of a person is determined from the change in received light data accompanying this decrease in brightness.

Referring to Figure 1 again, CCD sensors 1 and 2
receives a transfer clock from the CCD drive circuit 8 and outputs a light reception signal at regular accumulation time intervals, and the transfer clock outputs a light reception signal every approximately 44 ms accumulation exposure time when the interval D of the monitoring line is D = 10 cm. The accumulated charge accumulated in the light-receiving pixel of the CCD sensor is read out as a light-receiving signal.

The outputs of the CCD sensors 1 and 2 are sent to the A/D converter 9.
The signals a and 9b are converted into digital signals according to the received light level, and are provided to the multiplexer 10.

Here, since the CCD sensors 1 and 2 are equipped with, for example, 2048 light-receiving pixels, the readout time will be longer if the CCD sensors 1 and 2 are read out one after another.
Two systems of D converters 9a and 9b are provided, and the received light signals are read out in parallel to enable high-speed processing.

Following the multiplexer 10, there is a background processing circuit 11 for performing background processing on the received light data.
RAMs 12a and 12b are provided.

The light reception data of the A line and the B line obtained in a steady state with no people passing on the monitoring lines A and B are written in the RAM 12a, and this written light reception data is used for background processing by the background processing circuit 11. Used as background reference data for conversion. That is, the RAM 12a functions as background reference data storage means. Background processing circuit 11 is RAM 12
The received light data obtained in real time via the multiplexer 10 is subtracted from the background reference data stored in a, thereby creating received light data that is not affected by the background. This background processing of the light reception data is performed for each light reception data corresponding to the light reception pixel.
This is done through real-time processing.

On the other hand, light reception data is written in real time to the other RAM 12b, which is not used for storing background reference data, via the multiplexer 10, and background reference data can be written by switching from RAM 12a to RAM 12b as necessary. We are making it possible to refresh.

The received light data subjected to background processing by the background processing circuit 11 is written to a buffer memory 14a or 14b as a memory means via a gate circuit 13. The buffer memories 14a and 14b are connected via a gate circuit 15 to an arithmetic processing unit 16 that executes arithmetic processing for measuring the amount of traffic.

The reason why two buffer memories 14a and 14b are provided here is that when writing received light data into one buffer memory, for example, the buffer memory 14a, via the gate circuit 13, the other buffer memory 14b is written via the gate circuit 15. It is connected to the arithmetic processing unit 16, and the light reception data already stored in the buffer memory 14b is transferred to the arithmetic processing unit 16.
reads and processes the data.

In this way, by processing data in one buffer memory while writing data in the other buffer memory, timing alignment between the CCD sensor side and the arithmetic processing section 16 side becomes unnecessary, and the CCD sensor 1,
The transfer of the light reception data from 2 and the data processing by the arithmetic processing unit 16 can be made independent.

The arithmetic processing unit 16 is realized by program control by a CPU, for example, and reads the received light data stored in either one of the buffer memories 14a or 14b selected by the gate circuit 15, and performs arithmetic processing for measuring the amount of traffic. Execute. The arithmetic processing by the arithmetic processing unit 16 has the processing contents shown in the general flow of FIG.

First, data is read from the buffer memory 14a or 14b, as shown in FIG. 2, by reading received light data at preset regular intervals and performing data processing. Such data processing can be realized by specifying a jumping address for the buffer memory.

Based on the received light data from the buffer memory 14a or 14b input via the gate circuit 15, the arithmetic processing section 16 first reads the data on the A line as shown in block 18, and detects changes in the data. Subsequently, in block 19, a switch is made to reading data on the B line, and a change in the data is detected. Regarding the detection of data changes in blocks 18 and 19, the line position where the data change occurred is also detected at the same time.

Subsequently, in block 20, a pattern when a person passes through monitoring lines A and B shown in FIG. 6 is determined from changes in data on lines A and B.

In FIG. 6, time changes are shown for monitoring lines A and B when a person enters from the monitoring line A side located outside the entrance/exit, divided into times t1 to t3. Here, pattern 1 is the state in which the line is approaching the monitoring line A at time t1, and pattern 2 is the state in which it is approaching both the monitoring lines A and B at the time t2.
Then, pattern 3 is a state in which the signal passes through the monitoring line A and is connected to the monitoring line B. Of course, at the time of exit, a change from time t3 to t1 is obtained.

Therefore, in the pattern determination in block 20 of FIG. 5, which pattern in FIG. 6 is used is determined based on the A and B line data.

In the next block 21, the direction of movement is determined from the pattern determined in block 20 and the previous pattern that has already been registered. For example, pattern 1
is determined, the previous pattern is pattern 1
If the pattern is not one of patterns 1 to 3, the player is admitted, and if pattern 3 is determined and the previous pattern is not one of patterns 1 to 3, the player is allowed to leave. Of course, when pattern 2 is determined, if the previous pattern was pattern 1, the player will enter, and if pattern 3, the player will be allowed to leave.

Once the direction of movement has been determined, the number of entries and exits is counted in block 22. That is, if the user is entering, the counter is counted up, and if the user is leaving, the counter is counted down. When such measurement processing is completed, finally in block 23, the passing position of the person on the line obtained by the data processing so far and the pattern at the passing position are registered for use in determining the moving direction, and the block is again executed. 1
Return to step 8.

Referring again to FIG. 1, the number of people entering and leaving the building at that time, calculated by the arithmetic processing unit 16, is given to the display 17, which displays the number of people currently remaining in the building or the number of people entering the building.

Note that the arithmetic processing unit 16 includes a multiplexer 10,
It also controls gate circuits 13 and 15.

FIG. 7 is a circuit block diagram showing a specific embodiment of the arithmetic processing section 16 of FIG. 1.

First, to explain the configuration, 24 is an A line data reading circuit, 26 is a B line data reading circuit, and from among the background-processed light reception data stored in the buffer memory 14a or 14b, for example, every 16th light reception data is read. Read sequentially.

The outputs of the A line data reading circuit 24 and the B line data reading circuit 26 are applied to a data change detection circuit 30 via a changeover switch 28. The changeover switch 28 initially selects the A line data reading circuit 2.
4 side, and when 128 light reception data (light reception data read out every 16 light reception pixels from the light reception pixels corresponding to 2048 light reception pixels) is obtained from the A line data reading circuit 24, the B line data reading circuit 2
Switches to 6th side.

The data change detection circuit 30 is connected to the changeover switch 28.
The light reception data obtained through the sensor is compared with a predetermined threshold value to determine whether it is a person, and when the light reception data exceeding the threshold value is obtained, a data change detection output is generated. The output of the data change detection circuit 30 is given to a data change number counter 32, and the data change number counter 32 counts the number L of data changes obtained continuously. Also, data change detection circuit 3
The output of 0 is inverted by an inverter 34 and given to the empty number counter 36.
6 generates a counter output when there is no change in received light data for a predetermined number of vacancies, for example, two consecutive times;
The data change number counter 32 is reset.
For this reason, even if the data change number counter 32 performs a counting operation due to noise or the like, the state of data change does not continue, so a reset is applied in response to the output of the empty number counter 36, and the counting error in the number of data changes is prevent.

The output L of the data change number counter 32 is given to a digital comparator 38, and is compared with a threshold value Lo for the number of data changes determined based on the shoulder width of the person.
When the number of data changes L reaches the threshold value Lo, it is determined that one person has passed and a comparison output is generated. The threshold value Lo for determining the passage of a person based on the number of data changes can be determined, for example, based on the shoulder width H1 at the monitoring lines A and B shown in Figure 4, and the shoulder width H1 is statistically about 40 cm. For some reason, Lo=40
Set ÷4=10. Of course, the value of Lo can be changed as appropriate.

The output of the digital comparator 38 is applied to reset the data change number counter 32 so that the data change number counter 32 can determine whether the next person has passed. Further, the output of the digital comparator 38 is given to the pattern discrimination circuit 40, and the pattern discrimination circuit 40 selects the patterns 1 to 3 shown in FIG.
Determine which of the following applies. Furthermore, the output of the digital comparator 38 is also given to a position counter 42, and the position counter 42 receives a comparison output for each line A and B, that is, a value indicating how many people have passed from the end of the monitoring line. N is counted and given to the pattern discrimination circuit 40, and the pattern discrimination circuit 40 discriminates the pattern based on the correspondence with the position N. The pattern at position N discriminated by the pattern discrimination circuit 40 is stored in the data memory 44 and used for the next data processing.

Further, the discrimination output of the pattern discrimination circuit 40 is given to the next movement direction discrimination circuit 46, and the movement direction discrimination circuit 46 uses the pattern information obtained from the pattern discrimination circuit 40 and the previous discrimination pattern registered in the data memory 44. The moving direction is determined based on the moving direction, and the entry/exit counter 48 is caused to perform a counting operation based on the determined output of the moving direction.

8A, 8B, and 8C show flowcharts for realizing the circuit functions shown in FIG. 7 by program control.

First, FIG. 8A shows data processing of the A line.

When the apparatus is started, background reference data is set in block 50, and the next block 52
The data change number counter L, the position counter N, and the loop counter for monitoring the number of data processed per line are each initialized to zero.

Next, in block 54, the first A line data set by the loop counter is input, and in determination block 56, it is checked whether the data is equal to or greater than a threshold value in order to determine that it is a person. If the received light data is below the threshold, the loop counter is incremented in block 58, and the loop counter is checked in judgment block 60 to see if it has reached the final value = 128, until a data change exceeding the threshold is detected. The process of blocks 54-60 is repeated.

When the received light data exceeds the threshold value, the process proceeds from the judgment block 56 to block 62, where the length of the Nth line from the end of the monitoring line specified by the position counter N at this time, that is, the number of data changes L, is incremented.
A decision block 64 checks whether the threshold value Lo has been reached. If the threshold value Lo has not been reached, the loop counter is incremented in a block 66, and a decision block 68 checks whether the final value = 128 has been reached. The next A line data is inputted in block 70, and if it is equal to or greater than the threshold value, the process returns to block 62 again from judgment block 72, where the data change number L is incremented, and the data change number L is incremented.
Repeat this loop until =Lo is reached.

In addition, if received light data that does not exceed the threshold value is obtained before the data change number L reaches the threshold value Lo,
The process proceeds from judgment block 72 to judgment block 74, where the empty number counter is incremented, and when the count value of the empty number counter exceeds a predetermined value, block 7 is executed.
6, the number of data changes L is reset to zero, and the process returns to block 54 again.

In the judgment block 64, the number of data changes L is the threshold value Lo.
If it is determined that the loop counter has reached the final value, the process proceeds to block 78 to register the person's position N, and then increments the position counter N in block 80, and returns to block 54 again if the loop counter has not reached the final value. .

By processing the A line data in this way, if there is a change in brightness due to a person passing on the monitoring line A,
Based on the value of the position counter N, the passing position on the line and the number of people passing can be obtained as registered data.

When the final value of the loop counter is determined in decision block 60 or 68, the process proceeds to block 82, where the counters N and L are reset to zero, and the process proceeds to block 82.
The process proceeds to the B line data shown in the figure.

The processing of the B line data shown in FIG. 8B also
Since the processing is exactly the same as the processing of the A line data in FIG. 8A, each processing block is indicated by the same number with the addition numeral b.

When the data processing for the A line and the B line is completed in this way, the process proceeds to the pattern and movement direction determination process shown in FIG. 8C.

First, in the determination block 84, it is determined which of the patterns 1 to 3 shown in FIG. 6 is, and the process proceeds to any of the blocks 86a to 86c. Note that this pattern discrimination is performed in correspondence with the position counter N.

Next, in a determination block 88, the pattern is compared with the previously registered pattern to determine the direction of entry into block 90a or exit from block 90b. When determining the entrance to block 90a, the number of entrances and exits counter M is incremented by the number of people given by the position counter N. On the other hand, when leaving the block 90b, the number of entrances and exits counter M is given by the position counter N. Subtract by the number of people. Of course, since there may be a case where there is a mixture of persons entering and leaving the room, there may be cases where addition and subtraction of the entry/exit counter M are performed at the same time.

When the counting by the entry/exit number counter M is completed in this way, the determined pattern is registered together with the position in block 92, and the process is again performed in block 54 of FIG. 8A.
Return to

In the data processing shown in Figures 8A and 8B, when the number of data changes L reaches the threshold Lo, it is determined that the data change is due to the passage of a person; however, in order to further improve the detection accuracy, the threshold Lo is set in multiple stages, for example, in two stages, and the threshold value Lo for data processing of A and B lines is set to, for example, Lo=5 (20
cm), the pattern may be determined first, and after this pattern determination, the entry/exit counting operation may be performed after a data change reaching the threshold Lo=15 (60 cm on the line) is obtained.

FIG. 9 is a flowchart showing an example of the background reference data refresh process executed with the background reference data set shown in block 50 of FIG. 8A.

First, when the series of data processing shown in FIGS. 8A to 8C has been completed, the process advances to decision block 94 and checks the position counter N. If N=0, there is no one on the monitoring line, so the block At 96, the background reference data is refreshed. This refresh process is performed by the RAM 12a shown in FIG.
Since the light reception data is written in real time to one of the RAMs 12b, the background reference data is refreshed by switching from the RAM that was being used until then to the RAM that was being written in real time.

When this refresh is completed, the process proceeds to block 98, where the same initialization as shown in block 52 of FIG. 8A is performed, and through the ready cycle of decision block 100, the process proceeds to block 54 of FIG. 8A. Although the above-mentioned embodiment takes as an example the passage of a person as a moving body, the present invention is not limited to this, and it is also possible to detect the amount of passing vehicles or luggage. The interval between the two monitoring lines A and B may be set to an appropriate value based on the body size and moving speed.

Furthermore, in the case of moving objects such as vehicles that move in only one direction, the number of moving objects can be counted by simply providing one line of storage type photodetectors.

Further, in this embodiment, the movable body is monitored from above in the moving direction, but if the monitoring surface through which the movable body passes is made of a transparent plate or the like, it can be monitored from the bottom.

(Effects of the Invention) As described above, according to the present invention, at least two linear light-receiving pixels are arranged perpendicularly to the moving direction of the moving body in order to monitor changes in brightness on the monitoring surface. a storage type photodetector; a background reference data storage means for storing received light data obtained from the storage type photodetector only by a monitoring surface as background reference data; background processing means for subtracting the light reception data obtained from the type photodetector from the background reference data stored in the background reference data storage means;
a memory means for storing the light reception information obtained by the background processing means; and reading the light reception information stored in the memory means at predetermined time intervals, and determining the moving direction of the moving object based on the light reception information. Equipped with arithmetic processing means that determines the number of moving objects, it can accurately determine the number of people passing and the direction of movement even when multiple people pass side by side at the same time or when people entering and exiting cross each other. It is possible to detect the amount of traffic with extremely high accuracy.

Additionally, since a CCD sensor is used as the storage type photodetector, the detection optical system and data processing for determining traffic volume are simpler than in the conventional television camera system, making it possible to achieve high detection accuracy at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the structure of a CCD sensor used in the present invention, and FIG. 3 is an explanatory diagram showing the detection optical system of the present invention. Fig. 4 is an explanatory diagram showing the relationship between monitoring lines and people in a plan view, Fig. 5 is a general flowchart showing an overview of data processing by the arithmetic processing unit of Fig. 1, and Fig. 6 is a diagram showing the present invention. FIG. 7 is a circuit block diagram showing a specific embodiment of the arithmetic processing section in FIG. 1, and FIG. 8A and FIG.
Figures B and 8C are flowcharts showing the traffic volume measurement process of the present invention under program control, and Figure 9 is a flowchart showing the refresh process of background reference data. 1, 2...CCD sensor, 4...floor surface, 5...
Reflection mirror, 6... Condensing lens, 7... Half mirror, 8... CCD drive circuit, 9a, 9b...
A/D converter, 10...Multiplexer, 12
a, 12b...RAM, 11...background processing circuit,
13, 15...gate circuit, 14a, 14b...
Buffer memory, 16... Arithmetic processing unit, 17...
Display device, 24...A line data reading circuit, 26
... B line data reading circuit, 28 ... Selector switch, 30 ... Data change detection circuit, 32 ... Data change number counter, 34 ... Inverter, 36
. . . Free space counter, 38 . . . Digital comparator, 40 . . . Pattern discrimination circuit, 42 .

Claims (1)

[Scope of Claims] 1. At least two storage type photodetectors in which a plurality of linear light-receiving pixels are arranged perpendicularly to the moving direction of the moving object in order to monitor changes in brightness on the monitoring surface; and a monitoring surface. background reference data storage means for storing received light data obtained from the storage type photodetector by only the background reference data as background reference data; background processing means for subtracting the received light information from the background reference data stored in the background reference data storage means; memory means for storing the received light information obtained by the background processing means; What is claimed is: 1. A moving object amount measuring device comprising: arithmetic processing means for reading information at time intervals and determining the moving direction of moving objects based on the received light information and determining the number of moving objects.