JP2012117896A - Range finder, intruder monitoring device, and distance measuring method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a distance from an image of an article to the article, by a simple structure, in a range finder.SOLUTION: A range finder comprises shooting means 2, light projecting means 3 for projecting light on a shooting view field of the shooting means 2, and a control portion 5. The control portion 5 obtains an image (a non-light projection image) of a measured object when the light projecting means 3 does not project light, and an image (a light projection image) when projecting light; and calculates a distance from the shooting means 2 to the measured object from a luminance value of the non-light projection image, and luminance difference between the non-light projection image and the light projection image.

Description

  The present invention relates to a distance measuring device, an intruder monitoring device using the distance measuring device, a distance measuring method, and a program.

  In order to monitor an intruder in a monitoring area such as a building site, the camera has a camera (surveillance camera) that captures the surveillance area and an image processing device that processes a captured image of the surveillance camera. From an image (difference image) obtained by calculating a difference between a monitor image (a captured image at the time of monitoring), for example, a luminance difference for each pixel, and the like of an intruder or the like. An intruder monitoring device that detects the presence of a foreign object is conventionally known.

  Since the conventional intruder monitoring apparatus uses the difference image, it can detect the foreign object with high accuracy. However, if a foreign object is detected only from the difference image, a small animal such as a cat or a mouse that has entered the monitored area range is also detected as an intruder, so that false alarms may frequently occur.

  Therefore, in order to prevent such false alarms, it is equipped with a surveillance camera and a laser distance measuring device, and the distance to each object in the field of view is measured with the laser distance measuring device when there is no foreign object, Measure the distance to the foreign object when a foreign object enters while blocking those objects, and if the difference between the distance to the foreign object and the distance to the object blocked by the foreign object is greater than a predetermined distance, A method for determining the foreign object as an intruder has been proposed (see Patent Document 1). However, in this method, when an intruder stands in front of an object in the field of view, the difference in distance is small, and it is difficult to distinguish a small animal from the intruder.

  In addition, as a second method for preventing false reports by small animals, the distance from the surveillance camera to the foreign object is measured, and the actual size of the foreign object is calculated from the measured distance and the size of the foreign object in the difference image, A method for determining whether or not the foreign object is an intruder is also known. In other words, a camera having a distance measuring function is used as a surveillance camera, and the surveillance camera detects a foreign object, measures the distance to the foreign object, calculates the size of the foreign object, and determines whether the foreign object is a human. To do. Note that the actual size R of the object photographed by the surveillance camera is R = (D / D) from the size r of the image of the object on the imaging surface of the surveillance camera and the distance D from the surveillance camera to the object. f) × r (f is the focal length of the surveillance camera).

  As a camera having such a distance measurement function (distance camera), conventionally, an image sensor such as a CCD, and a light emitting diode (LED: Light Emitting Diode) that irradiates a light pulse with a fixed period in the photographing field of view of the image sensor, A light gate that is disposed in front of an image pickup surface of the image pickup device and that passes or blocks (turns on / off) light incident on the image pickup device, and after the LED irradiates the object with a light pulse, There is a method of measuring distance by a method (TOF method: Time-of-Flight method) of measuring a time until reflected light is received by an imaging element and measuring a distance to the object (see Patent Document 2). ). That is, the time (delay time) from when the irradiation light pulse is emitted until the light gate is turned on (transmission state) is gradually changed, and the reflected light from the object passes through the light gate and is received by the imaging device. The distance to the object is calculated from the above delay time.

  As a second example of the conventional distance camera, an object is photographed by two cameras arranged at a predetermined distance, and the position of the object on the photographed image of each camera is used according to the principle of triangulation. A method of measuring distance by a method of measuring a distance to an object (stereo camera method or stereo matching method) is known (see Patent Document 3).

  However, if the conventional distance camera uses the TOF method, a special light gate or a processing device that operates at high speed is required to measure the time difference from when the irradiated light is emitted until when the reflected light is received. In the case of using the stereo camera method, since at least two cameras are required, there is a problem that the configuration is complicated and expensive. Therefore, there is a demand for a surveillance camera that has a simpler configuration and is therefore less expensive.

Japanese Patent No. 4460782 Japanese Patent Laid-Open No. 7-110381 JP 2006-172253 A

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to measure a distance to an object based on an image of the object with a simple configuration.

The present invention includes a photographing unit and a light projecting unit that projects light onto a photographing field of view of the photographing unit, and based on the image of the object to be photographed by projecting from the light projecting unit, A distance measuring device for measuring a distance to an object to be measured, wherein the light emitting state of the light projecting means is a first light emitting state and a second light emitting state having a higher illuminance than the first light emitting state. Brightness acquisition means for acquiring the brightness of the image of the object to be measured, brightness of the image of the object in the first light emission state measured in advance for each distance from the photographing means, and the first and first Based on the luminance difference of the image of the object in two light emission states, the luminance of the image of the object acquired in the first light emission state and the object to be acquired acquired in the first and second light emission states From the luminance difference of the image, from the photographing means A calculating means for calculating the distance to the measurement object is a distance measuring apparatus having a.
Further, the present invention detects the foreign matter in the monitoring area from the difference image between the background image when there is no foreign matter in the monitoring area and the monitoring image for monitoring the intrusion of the foreign substance into the monitoring area. An intruder monitoring device for detecting an intruder in an area, the distance measuring device according to any one of claims 1 to 3, and a distance from the imaging means measured by the distance measuring device to the foreign object A foreign substance size calculating means for calculating the foreign substance size from the size of the foreign substance image in the difference image, and an alarm generating means for issuing an alarm when the foreign substance size calculated by the foreign substance size calculating means is a predetermined size or more. , An intruder monitoring device.
In addition, the present invention includes an imaging unit and a light projecting unit that projects light onto a field of view of the imaging unit, and the imaging unit is based on an image of an object to be measured that is projected from the light projecting unit. A distance measuring method in a distance measuring device for measuring a distance from the object to be measured, wherein the light emitting state of the light projecting means is a second light emitting state having a higher illuminance than the first light emitting state and the first light emitting state. A step of acquiring the luminance of the image of the object to be measured when the light emitting state is set; the luminance of the image of the object in the first light emitting state, which is measured in advance for each distance from the photographing unit; Based on the luminance difference between the images of the object in the first and second light emission states, the luminance of the image of the measurement object acquired in the first light emission state and the images obtained in the first and second light emission states. From the brightness difference of the image of the object to be measured, Wherein the imaging means is a distance measuring method comprising the steps of: calculating a distance to the object to be measured, a.
In addition, the present invention includes an imaging unit and a light projecting unit that projects light onto a field of view of the imaging unit, and the imaging unit is based on an image of an object to be measured that is projected from the light projecting unit. The distance measuring device computer that measures the distance from the object to be measured has the light emitting state of the light projecting means as a first light emitting state and a second light emitting state having a higher illuminance than the first light emitting state. Brightness acquisition means for respectively acquiring the brightness of the image of the object to be measured, the brightness of the image of the object in the first light emission state measured in advance for each distance from the photographing means, and the first And the luminance of the image of the measurement object acquired in the first light emission state based on the luminance difference of the image of the object in the second light emission state, and the object acquired in the first and second light emission states. From the brightness difference of the image of the measurement object, Wherein the means is a program for functioning as a calculating means, for calculating the distance to the object to be measured.

  According to the present invention, the distance to an object can be measured based on the image of the object with a simple configuration, and an intruder monitoring apparatus that is unlikely to cause false alarms by small animals or the like is configured at low cost. be able to.

It is a block diagram which shows the structure of the ranging device which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the distance calculation information which a memory | storage part memorize | stores in the distance measuring device which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the control part in the distance measuring device which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement procedure of the distance measuring device which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the procedure of the calibration mode process in the distance measuring device which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the procedure of the measurement mode process in the distance measuring device which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the procedure of the imaging | photography mode process in the distance measuring device which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the intruder monitoring apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the operation | movement procedure of the intruder monitoring apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the procedure of the monitoring mode process in the intruder monitoring apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the procedure of the background acquisition process in the intruder monitoring apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the procedure of the monitoring process in the intruder monitoring apparatus which concerns on the 3rd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the distance measuring apparatus according to the first embodiment of the present invention.
The distance measuring device 1 includes a photographing unit 2 including a lens and an imaging device such as a CCD, and a light projecting unit 3 that projects light from the direction of the photographing unit 2 onto a photographing field of view of the imaging device. Here, as the photographing means 2 and the light projecting means 3, for example, a commonly used camera with a projector equipped with a visible light lamp or an infrared lamp can be used. In the following description, an image projected and projected by the light projecting unit 3 is referred to as a projected image, and an image captured without projecting is referred to as a non-projected image.

  The distance measuring apparatus 1 also includes a luminance value I of a non-projected image of the object, a luminance value I and a distance from the photographing means 2 to the object (photographing distance L), and a non-projected image of the object. A storage unit 4 that stores distance calculation information indicating a relationship with a luminance difference ΔI with a projected image, a control unit 5 that controls the operation of each unit such as the photographing unit 2, and a user gives an operation instruction to the control unit 5 And an operation display unit 6 composed of a touch panel or the like which is also a display means for displaying images and various data to the user.

Here, the distance calculation information stored in the storage unit 4 will be described below.
When the light projecting unit 3 projects an object by projecting from the direction of the image capturing unit 2 to the field of view of the image capturing unit 2, the object is light from a fluorescent lamp or the sun existing in the image capturing environment (environmental illumination). ) And light emitted from the light projecting means 3. Among these, since the intensity of light emitted from the light projecting means 3 and reaching the object is inversely proportional to the square of the distance to the object, the luminance difference ΔI between the projected image and the non-projected image of the object is Is closer to the light projecting means 3 and therefore closer to the photographing means 2.

  On the other hand, the luminance value I of the image obtained by using the photographing means 2 such as a CCD is generally a value after gamma correction performed inside the photographing means 2, and therefore the actual luminance of the object and the output from the photographing means 2. The relationship with the luminance value I is not linear. For this reason, the luminance difference ΔI calculated from the non-projected image and the projected image usually depends on the luminance value I of the non-projected image of the object.

  Therefore, the relationship between the distance (shooting distance) L from the photographing means 2 to the object, the luminance value I of the non-projected image of the object, and the luminance difference ΔI between the projected image and the non-projected image is expressed by the luminance value I. If a calculation formula for obtaining the shooting distance L from the luminance value I and the luminance difference ΔI is derived based on these measurement values in advance while changing the shooting distance L for a plurality of different objects, the shooting formula L The distance to an object whose distance is unknown can be calculated. Even when the calculation formula cannot be derived, the distance to the object whose shooting distance is unknown can be calculated by using the interpolation method or the extrapolation method for the measurement value.

In the present embodiment, the distance to the object is calculated using an interpolation method or an extrapolation method with respect to the measurement values of the shooting distance L, the luminance value I, and the luminance difference ΔI, and the measurement values are used as the distance calculation information. Is stored in the storage unit 4.
That is, the distance calculation information stored in the storage unit 4 includes the distance (shooting distance) L from the photographing means 2 to the object, the luminance value I of the non-projected image of the object, and the projected image and the non-projected image. The brightness difference ΔI is created based on measurement values obtained by measuring in advance while changing the shooting distance L for a plurality of objects having different brightness values I.

FIG. 2 is a diagram illustrating an example of the distance calculation information stored in the storage unit 4.
In the distance calculation information shown in FIG. 2A, the shooting distance L, the luminance value I of the non-projected image, and the luminance difference ΔI between the non-projected image and the projected image are described from the left column to the right. . The luminance value I and the luminance difference ΔI are represented by luminance gradation values expressed in 256 gradations.

  For this distance calculation information, for example, a projected image and a non-projected image are acquired by the photographing means 2 and the light projecting means 3 while changing the photographing distance L using a test chart composed of three areas having different luminances. Can be created.

  FIG. 2B is a graph showing the relationship between the luminance value I and the luminance difference ΔI in the distance calculation information shown in FIG. 2A. The horizontal axis represents the luminance value I, the vertical axis represents the luminance difference ΔI, and the shooting distance L is 3 m. , 6 m, and 9 m are plotted.

Using the distance calculation information shown in FIG. 2A, the shooting distance L can be calculated as follows for an object Z whose shooting distance L is unknown.
As an example, assume that the brightness value I of the non-projected image of the object Z is 100 and the brightness value of the projected image is 120. Therefore, the luminance difference ΔI is 20 (= 120−100).

  First, from the measurement values shown in the distance calculation information of FIG. 2A, the luminance difference ΔI at the luminance value I = 100 is calculated by linear interpolation (linear approximation) for each of the shooting distances L of 9 m, 6 m, and 3 m. Then, ΔI = 14.36 at L = 9 m, ΔI = 33.73 at L = 6 m, and ΔI = 73.31 at L = 3 m.

  The luminance difference ΔI = 20 of the object Z is between the luminance difference ΔI = 14.36 at L = 9 m calculated above and the luminance difference ΔI = 33.73 at L = 6 m. Is between 9m and 6m. Therefore, when the shooting distance L at which ΔI = 20 is obtained from these values by the linear interpolation method, the shooting distance L of the object Z is 8 m.

  In the above example, the linear interpolation method (bilinear interpolation method) in the three-dimensional space (L, I, ΔI) is used. However, other interpolation methods (for example, biquadratic interpolation method or bi-3 interpolation method) are used. The following interpolation method can also be used. Further, by using an extrapolation method such as a linear extrapolation method or a quadratic extrapolation method, for example, an imaging distance L of an object farther than 9 m from the light projecting means 3 or an object closer than 3 m is calculated. You can also.

  In addition, instead of obtaining the object photographing distance L using the interpolation method as in the above example, the object photographing distance L may be obtained as a distance range based on the measured values shown in FIG. 2A. (In the above example, the shooting distance L is 6 m or more and less than 9 m). When it is desired to specify the shooting distance L in a narrower distance range, as shown by a dotted line in FIG. 2C, the shooting distance L is different from the measured shooting distance L (4 m, 5 m, 7 m, and 8 m in FIG. 2C). The relationship between the luminance value I and the luminance difference ΔI is calculated in advance by an interpolation method and added to the distance calculation information (table in FIG. 2A).

  Further, in the above description, an object is photographed when the light projecting means 3 is ON (lighted) and OFF (light extinguished), and the distance of the object is calculated from the projected image and the non-projected image. However, when the ambient illumination is dark and a non-projected image with appropriate brightness cannot be obtained, the light emitting means 3 is turned on in two light emitting states with different illuminances, and the distance to the object is set. Can also be calculated. That is, the light projecting means 3 is turned on in the first light emitting state and the second light emitting state that is brighter (higher illuminance) than the first light emitting state, and the first light emission is used instead of the non-projected image. It is also possible to calculate the distance to the object by using the image captured in the second light emitting state instead of the projected image.

FIG. 3 is a block diagram illustrating a configuration of the control unit 5.
The control unit 5 is a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporary storage of data, and the like. The image acquisition means 51 for acquiring the non-projected image and the projected image of the object in the field of view of the imaging means 2 by controlling the means 3, and the brightness of the non-projected image and the projected image of the object, respectively. The distance to the object is calculated from the brightness acquisition means 52 that acquires and specifies the brightness value I and the brightness difference ΔI, the specified brightness value I, the brightness difference ΔI, and the distance calculation information stored in the storage unit 4. A distance calculation unit 53 that is a calculation unit that performs calculation, a calculation information generation unit 54 that generates distance calculation information stored in the storage unit 4, and an external device (for example, a personal computer (PC)). A communication interface 55 for exchanging information such as instructions and data, a has.

  Here, each of the above-described units included in the control unit 5 is a function realizing unit of the control unit (computer) 5 realized by a program. The computer program can be stored in any computer-readable storage medium.

  In the distance measuring apparatus 1 having the above-described configuration, when the user turns on the imaging field of view of the imaging unit 2 to an object and then turns on the power and starts shooting with the operation display unit 6, first, the control unit 5 The light unit 3 is controlled to be turned on and off, and the photographing unit 2 acquires a non-projected image and a projected image of the object. Next, the control unit 5 obtains the luminance value I from the non-projected image and the luminance difference ΔI from the non-projected image and the projected image, and refers to the distance calculation information stored in the storage unit 4. The shooting distance L of the object is calculated.

  As a result, the distance measuring device 1 is based on the image of the object with a simple configuration combining the photographing means 2 and the light projecting means 3, such as a commonly used camera with a light projector, without using special parts. The distance to the object can be measured.

  Next, the operation procedure of the distance measuring apparatus 1 will be described with reference to the flowchart shown in FIG. The distance measuring device 1 has three operation modes, that is, a calibration mode for storing the distance calculation information in the storage unit 4, a shooting mode for shooting an object in the shooting field of view, and shooting the object as well as the object. It has a measurement mode to measure the distance.

  First, when the user turns on the distance measuring apparatus 1 (S101), the control unit 5 displays a screen (operation mode input screen) for inputting an operation mode on the operation display unit 6 (S102). Is determined (S103), and when the operation mode is not input (S103, No), it waits until it is input. On the other hand, when the operation mode is input (S103, Yes), it is determined whether or not the input operation mode is the calibration mode (S104). When the operation mode is the calibration mode (S104, Yes), the calibration mode processing is performed. After that (S105), the process returns to step S102.

In step S104, when the input operation mode is not the calibration mode (S104, No), it is determined whether or not the input operation mode is the measurement mode (S106). When the input operation mode is the measurement mode (S106, After performing the measurement mode process (S107), the process returns to step S102.
On the other hand, when the input operation mode is not the measurement mode, that is, when it is the photographing mode (S106, No), the photographing mode process is performed (S108), and the process returns to step S102.

Next, the procedure of the calibration mode process in the distance measuring device 1 will be described with reference to the flowchart shown in FIG.
When the calibration mode process is started, the control unit 5 displays a screen for the user to input a shooting start instruction on the operation display unit 6 (S201), and determines whether or not the shooting start instruction is input (S202). ). If no photographing start instruction is input (S202, No), the process waits until it is input.

  During this standby period, the user prepares a test chart composed of, for example, three areas having different luminances, and places the test chart at a position away from the photographing unit 2 by a predetermined distance. When the arrangement of the test chart is completed, an imaging start instruction is input to the operation display unit 6.

  When a shooting start instruction is input from the operation display unit 6 (S202, Yes), the control unit 5 uses the image acquisition unit 51 to turn off the light projection unit 3 and acquire a non-projected image of the test chart ( In step S203, the light projection unit 3 is turned on to obtain a light projection image of the test chart (S204).

  Next, the control unit 5 displays a projected image of the test chart on the operation display unit 6, and obtains a luminance value I and a luminance difference ΔI for the user (measurement target region), and the measurement target region. A message prompting the user to input the distance (shooting distance L) is displayed (S205). Subsequently, the control unit 5 determines whether or not the measurement target region and its photographing distance L are input (S206). If not input (S206, No), the control unit 5 stands by until it is input.

  Here, for example, the user inputs a region on the test chart arranged in the photographing field of view as a measurement target region, and inputs the distance from the photographing means 2 to the test chart as the photographing distance L. Note that the measurement target area can be input by, for example, a user drawing a rectangle on the test chart image using a pointing device (not shown) such as a mouse.

  When the user inputs the measurement target region and its shooting distance L (S206, Yes), the luminance acquisition unit 52 of the control unit 5 determines the luminance value I of the designated measurement target region based on the non-projected image and the projected image. And the luminance difference ΔI is acquired (S207). Here, the luminance value I and the luminance difference ΔI are, for example, a luminance gradation value representing the average luminance value and the average luminance difference of each pixel in the input measurement target area in 256 gradations, respectively. Can be obtained as

  Next, the control unit 5 stores the photographing distance L input in step S206, the luminance value I and the luminance difference ΔI obtained in step S207 in the storage unit 4 as distance calculation information (S208), and the operation display unit. 6 displays a screen for inputting an instruction to continue or end the calibration mode process (S209). Subsequently, the control unit 5 determines whether or not a calibration work continuation instruction is input to the operation display unit 6 (S210). When a continuation instruction is input (S210, Yes), the process returns to step S201. Repeat the process.

  On the other hand, when the continuation instruction is not input, that is, when the end instruction is input (S210, Yes), the calculation information generating means 54 is based on the measured values (L, I, ΔI) measured. A luminance difference ΔI with respect to a predetermined luminance value I at a predetermined shooting distance L is calculated by interpolation or extrapolation (S211). Subsequently, the control unit 5 stores the predetermined photographing distance L and luminance value I and the calculated luminance difference ΔI in the storage unit 4 as distance calculation information (S212), and ends the process.

Here, for example, in the example shown in FIG. 2, the predetermined shooting distance L is set to 4 m, 5 m, 7 m, and 8 m (dotted line in FIG. 2C). It can be calculated information. Further, as the predetermined luminance value I, for example, an interval of 10 gradations from a gradation value of 10 to 250 can be set. Thereby, in the measurement mode processing described later, the shooting distance of an object whose shooting distance is unknown can be specified with an accuracy of 1 m without performing calculation by interpolation or extrapolation each time the distance is measured.
In addition, when calculating | requiring the imaging distance of an object by the interpolation method or the extrapolation method for every distance measurement, the process of said step S211 and S212 is unnecessary.

Next, the procedure of the measurement mode process in the distance measuring device 1 will be described with reference to the flowchart shown in FIG.
When the measurement mode process is started, the control unit 5 displays a screen for the user to input a shooting start instruction on the operation display unit 6 (S301), and determines whether a shooting start instruction is input (S302). . If no shooting start instruction is input (S302, No), the process waits until it is input.

  On the other hand, when an operation start instruction is input to the operation display unit 6 (S302, Yes), the image acquisition unit 51 of the control unit 5 turns off the light projecting unit 3 and the non-projected image of an object in the field of view. (S303), the light projecting means 3 is turned on to obtain a projected image of the object (S304). Next, the luminance acquisition unit 52 of the control unit 5 acquires the luminance value I and the luminance difference ΔI for each pixel based on the acquired non-projected image and the projected image (S305), and the storage unit 4 stores them. Referring to the calculated distance calculation information (S306), the shooting distance L for each pixel is calculated from the distance calculation information, the luminance value I and the luminance difference ΔI for each pixel (S307), and the process is terminated.

  Here, the imaging distance L for each pixel calculated in step S307 may be transmitted to another device (such as a PC) via the communication interface 55, for example. Further, the non-projected image or the projected image acquired in step S303 or S304 is displayed on the operation display unit 6, and the shooting distance L of a pixel at a predetermined position designated by the user with a mouse or the like (not shown) is displayed on the operation display unit. 6 may be displayed. Further, the control unit 5 adds a color corresponding to the shooting distance L to each pixel, and generates an image (distance image) in which a difference in shooting distance of each object existing in the shooting field of view is displayed as a color difference. Then, it may be displayed on the operation display unit 6.

  In the present embodiment, the measurement mode process is completed by only obtaining the projected image and the non-projected image once and calculating the shooting distance. However, after calculating the shooting distance, the process returns to step S303. The process may be repeated. As a result, the shooting distance can be measured in real time to capture the movement of the object. When the measurement mode process is repeated in this way, a measurement end button is displayed at the corner of the display area of the operation display unit 6 and the operation display unit 6 controls the control unit when the user presses the measurement end button. An interrupt signal may be transmitted to 5 to end the measurement mode process.

Next, the procedure of photographing mode processing in the distance measuring device 1 will be described with reference to the flowchart shown in FIG.
When the photographing mode process is started, the control unit 5 displays a screen for inputting a lighting instruction or a light-off instruction for the light projecting means 3 on the operation display unit 6 (S401), and whether or not the lighting instruction is input. Judgment is made (S402). When a lighting instruction is input (S402, Yes), if the light projecting means 3 is not turned on, the light projecting means 3 is turned on (S403). On the other hand, when the lighting instruction is not input (S402, No), it is determined whether or not the lighting instruction is input (S404). When the lighting instruction is input (S404, Yes), the light projecting means 3 is determined. If is lit, the light projecting means 3 is turned off (S405). If no turn-off instruction is input in step S404 (No in S404), the process returns to step S402 and the above process is repeated until a turn-on instruction or turn-off instruction is input.

  Next, the control unit 5 displays a screen for the user to input a shooting start instruction on the operation display unit 6 (S406), and determines whether or not the user has input a shooting start instruction (S407). If no shooting start instruction is input (S407, No), the process waits until it is input.

  On the other hand, when a shooting start instruction is input to the operation display unit 6 (S407, Yes), the image acquisition unit 51 of the control unit 5 acquires an image of an object in the shooting field of view (S408), and then acquires the acquired image. Is displayed on the operation display unit 6 (S409), and the process is terminated.

  In the above-described shooting mode process, the shooting mode process is completed by simply acquiring an image of the shooting field of view once and displaying it on the operation display unit 6. It is good also as what returns to S408 and repeats a process. As a result, an image in the field of view can be taken in real time. In this case, a shooting end button is displayed at the corner of the display area of the operation display unit 6 and an interrupt signal is transmitted from the operation display unit 6 to the control unit 5 when the user presses the shooting end button. The shooting mode process may be terminated.

  In the calibration mode process, the measurement mode process, and the shooting mode process described above, information (such as a shooting start instruction and a measurement target area) input using the operation display unit 6 is communicated from another device (such as a PC). It may be provided via the interface 55.

Next, a distance measuring apparatus according to the second embodiment of the present invention will be described.
In the distance measuring device, the distance calculation unit 53 calculates the shooting distance L from the luminance value I and the luminance difference ΔI without using the distance conversion information stored in the storage unit 4 in the distance measuring device 1 according to the first embodiment. The distance to the object is calculated using a calculation formula.

  According to the present embodiment, the distance to the object can be easily calculated without using an interpolation method or an extrapolation method.

  Specifically, the calculation formula for obtaining the shooting distance L is the distance (shooting distance) L from the shooting means 2 to the object, the luminance value I of the non-projected image of the object, and the projected image and the non-projected image. Is derived using a mathematical method such as a linear approximation method or a quadratic curve approximation method based on measurement values obtained in advance by changing the shooting distance L for a plurality of objects having different luminance values I. can do.

  In the above measurement, when the ambient illumination is dark and a non-projected image having an appropriate brightness cannot be obtained, the light projecting means 3 is brighter than the first light emitting state and the first light emitting state (the illuminance is low). (Large) lighted in the second light emitting state, using an image taken in the first light emitting state instead of the non-projected image, and an image taken in the second light emitting state instead of the projected image, The brightness value I and the brightness difference ΔI may be measured to derive the above calculation formula.

Next, a third embodiment of the present invention will be described.
The present embodiment is an intruder monitoring apparatus using the distance measuring device according to the present invention as a monitoring camera for photographing a monitoring area such as a building site.
FIG. 8 is a block diagram showing a configuration of the intruder monitoring apparatus 7 according to the present embodiment.
The intruder monitoring device 7 gives an operation instruction to the distance measuring device 1 ′ and the distance measuring device 1 ′, acquires an image from the distance measuring device 1 ′, processes the image, and detects an intruder. 8, a data bus 9 that connects the distance measuring device 1 ′ and the processing unit 8, an image storage unit 10 that stores image data acquired by the distance measuring device 1 ′, and a user gives an operation instruction to the processing unit 8. An operation display unit 11 constituted by a touch panel or the like, which is an input means for input and the display unit for the processing unit 8 to display images and data to the user, and a warning when the processing unit 8 detects an intruder The speaker 12 which emits.

  Like the distance measuring device 1 according to the first embodiment, the distance measuring device 1 ′ includes the photographing unit 2, the light projecting unit 3, and the storage unit 4, but does not include the operation display unit 6, but includes an operation display unit. Control that operates according to an operation instruction received via the data bus 9 instead of the control unit 5 that operates in response to an input from 6, and transmits information such as image data to the processing unit 8 via the data bus 9. Part 5 ′.

  Similar to the control unit 5 in the distance measuring apparatus 1 according to the first embodiment, the control unit 5 ′ includes an image acquisition unit 51, a luminance acquisition unit 52, a distance calculation unit 53, a calculation information generation unit 54, and a communication interface. 55.

  The processing unit 8 is a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporarily storing data, and the like from the distance measuring device 1 ′. Based on the acquired image of the field of view (background image) in the absence of a foreign object such as an intruder and the image of the field of view (monitoring image) at the time of monitoring, the difference (for example, luminance) between the monitoring image and the background image A foreign object detection means 81 for detecting a foreign object from an image (difference image) obtained by calculating (difference).

  Further, the processing unit 8 calculates the size of the foreign object from the distance to the foreign object measured by the distance measuring device 1 ′ and the size (for example, the number of pixels) of the foreign object image (foreign object image) in the difference image. When the size of the foreign matter calculated by the size calculation means 82 and the foreign matter size calculation means 82 is equal to or larger than a predetermined size, the alarm generation means 83 that determines that the foreign matter is an intruder and issues an alarm, and the data bus 9 And a communication interface 84 for exchanging data with the distance measuring device 1 '.

  In this embodiment, as the computer for operating the intruder monitoring device 7, the control unit 5 ′ that is a computer included in the processing unit 8 and the distance measuring device 1 ′ is used, but the processing is performed without using the control unit 5 ′. The unit 8 may be configured to control each unit of the distance measuring device 1 ′ and implement each unit included in the control unit 5 ′. Alternatively, the image stored in the image storage unit 10 may be stored in the storage unit 4 without using the image storage unit 10.

When the intruder monitoring device 7 having the above configuration detects a foreign object from the difference image obtained from the background image and the monitoring image, the intruder monitoring device 7 measures the distance to the foreign object by the distance measuring device 1 ′, and the size of the foreign object image in the difference image. The size of the foreign object is calculated from the distance to the foreign object, and whether or not the foreign object is an intruder is determined based on the size.
Thereby, the intruder monitoring apparatus 7 can distinguish small animals, such as a mouse, and a person, and can prevent mistaken information from being mistaken for a small animal as an intruder.

  Next, the operation procedure of the intruder monitoring apparatus 7 will be described with reference to the flowchart shown in FIG. The intruder monitoring device 7 has two operation modes: a calibration mode for storing the distance calculation information in the storage unit 4 and a monitoring mode for monitoring the intruder. In the following description, it is assumed that the shooting field of view of the shooting unit 2 is already set so that a monitoring area such as a building site or indoors can be shot.

  First, when the user turns on the power of the intruder monitoring device 7 (S501), the processing unit 8 displays a screen for inputting the operation mode on the operation display unit 11 (S502), and whether the operation mode is input. Whether or not the operation mode is not input (S503, No), it waits until it is input. On the other hand, when the operation mode is input (S503, Yes), it is determined whether or not the input operation mode is the monitoring mode (S504). When the operation mode is the monitoring mode (S504, Yes), the monitoring mode processing is performed. After performing (S505), it returns to step S502.

  In step S504, when the input operation mode is not the monitoring mode, that is, in the calibration mode (S504, No), the calibration mode process is performed (S506), and the process returns to step S502.

  The calibration mode process in step S506 is the same as the calibration mode process shown in FIG. 5 except that the operation display unit 11 is used instead of the operation display unit 6.

Next, the procedure of the monitoring mode process in the intruder monitoring device 7 will be described with reference to the flowchart shown in FIG.
When the monitoring mode process is started, the processing unit 8 operates a screen (operation instruction input screen) for inputting either a background image acquisition instruction (background acquisition instruction) or a monitoring image acquisition instruction (monitoring operation instruction). It is displayed on the display unit 11 (S601).

  Next, the processing unit 8 determines whether or not any of the above operation instructions has been input (S602), and if no operation instruction has been input (S602, No), either is input. Wait until On the other hand, when any instruction is input (S602, Yes), it is determined whether the input instruction is a monitoring operation instruction (S603), and when it is a monitoring operation instruction (S603, Yes). After performing the monitoring process (S604), the process returns to step S601 to repeat the process.

  On the other hand, if the input instruction is not a monitoring operation instruction in step S603, that is, if it is a background acquisition instruction (No in S603), after performing the background acquisition process (S605), the process returns to step S601 and repeats the process. .

Next, the procedure of the background acquisition process in the intruder monitoring device 7 will be described according to the flowchart shown in FIG.
When the background acquisition process is started, the processing unit 8 sends, via the data bus 9, a command for instructing the distance measuring device 1 ′ to acquire a non-projected image and a projected image within the photographing field of view (that is, the monitoring area). Transmit (S701).

  The control unit 5 ′ of the distance measuring apparatus 1 ′ receives the above command, and after the image obtaining unit 51 first turns off the light projecting unit 3 to obtain a non-projected image in the monitoring area (S 702), the light projection is performed. The means 3 is turned on to obtain a projection image of the monitoring area (S703). Subsequently, the control unit 5 ′ stores the acquired no-projection image and the projection image in the storage unit 4 as a background image at the time of no projection and a background image at the time of projection, respectively (S704). The image is transmitted to the processing unit 8 via the data bus 9 (S705).

  The processing unit 8 receives the non-projected image and the projected image transmitted from the control unit 5 ′, and uses these images as a background image at the time of no projection and a background image at the time of projection, respectively. (S706) and the background acquisition process is terminated.

Next, the procedure of the monitoring process in the intruder monitoring device 7 will be described with reference to the flowchart shown in FIG. It is assumed that distance calculation information in the installation environment of the intruder monitoring device 7 has already been stored in the storage unit 4 of the distance measuring device 1 ′.
When the monitoring operation process is started, the processing unit 8 transmits a command to the distance measuring device 1 ′ in the same manner as the image acquisition operation (steps S701 to S705 in FIG. 11) in the background acquisition process described above. In step S801, a non-projected image and a projected image of the monitoring area are acquired. At this time, as in step S704 in FIG. 11, the control unit 5 ′ stores the non-projected image and the projected image in the monitoring area in the storage unit 4 as a monitoring image at the time of no projection and a monitoring image at the time of projection. It shall be remembered.

  Next, the processing unit 8 stores the non-projected image and the projected image of the monitoring area acquired by the distance measuring device 1 ′ in the image storage unit 10 as a monitoring image at the time of no projection and a monitoring image at the time of projection, respectively. Store (S802).

  Subsequently, the foreign matter detection means 81 of the processing unit 8 refers to each image stored in the image storage unit 10 and generates a difference image at the time of no light projection and a difference image at the time of light projection (S803). The generation of the difference image at the time of no light projection and at the time of light projection is performed by calculating the absolute value of the difference between the background image and the monitoring image, for example, the luminance difference for each pixel at the time of no light projection and at the time of light projection, respectively. Generate.

  Next, the foreign object detection means 81 determines whether or not a foreign object is shown in the difference image between the non-projection and the projection (S804). Here, for example, whether or not a foreign object is included in the difference image is determined by performing binarization processing for extracting only pixels (foreign pixel) having a luminance value larger than a predetermined value for each difference image. When the labeling process is performed and the number of adjacent foreign pixel pixels exceeds a predetermined number, it can be determined that there is a foreign matter.

In step S804, when a foreign object is not shown in either the difference image at the time of no light projection or the difference image at the time of light projection (S804, No), the process returns to step S801 and the process is repeated.
On the other hand, in step S804, when a foreign object appears in both the no-light-projecting and the difference images at the time of projecting (S804, Yes), the foreign-material size calculating unit 82 of the processing unit 8 The number of pixels in the vertical direction and the horizontal direction of the foreign matter reflected in the difference image at the time of projection is calculated (S805).

  Subsequently, the foreign substance size calculation means 82 of the processing unit 8 transmits a command (calculation instruction command) for instructing the distance measuring device 1 ′ to calculate the distance to the foreign substance (foreign object photographing distance L) ( S806). Here, for example, the above calculation instruction command can be configured by adding information on the position of the foreign pixel in the monitoring image at the time of no light projection and at the time of light projection as a target position for distance calculation.

  Next, the control unit 5 ′ receives the calculation instruction command, and is designated by the distance calculation unit 53 by the calculation instruction command based on the no-lighting and light-monitoring monitoring images stored in the storage unit 4. The photographing distance L of each foreign pixel at the position is calculated and transmitted to the processing unit 8 (S807).

  The processing unit 8 receives the shooting distance L of each foreign pixel, and the foreign size calculation means 82 calculates the average value of the received shooting distance L of the foreign pixel and sets it as the distance to the foreign object (S808). Here, the distance to the foreign object can be the minimum value, the maximum value, or the median value of the imaging distance L of the foreign object pixel in addition to the average value. Further, when the shooting distance L of each foreign pixel is expressed as a distance range, the average value of the median value of the distance range, the minimum value of the lower limit value, or the maximum value of the upper limit value can also be used.

  Next, the foreign substance size calculation means 82 determines the size of the foreign substance (vertical direction and horizontal direction) based on the number of vertical and horizontal pixels of the foreign substance calculated in step S805 and the distance to the foreign substance calculated in step S808. (Size) is calculated (S809). Subsequently, the alarm generation unit 83 determines whether or not the calculated size of the foreign material is equal to or larger than a predetermined size (S810), and is larger than the predetermined size (for example, the vertical and horizontal sizes are both predetermined). (S810, Yes), the foreign object is determined to be an intruder, and a warning sound is emitted from the speaker 12 as an alarm indicating that the intruder has been detected (S811), and the monitoring process is performed. finish.

  It should be noted that after the alarm is generated, the alarm can be continuously issued without ending the monitoring process. In this case, for example, the alarm can be canceled by a reset switch (not shown) or the like provided in the operation display unit 11, and the monitoring process can be terminated. Further, as an alarm issued by the alarm generation means 83, instead of sounding an alarm sound from the speaker 12, a red lamp blinks, or an alarm signal is transmitted to a monitoring device (not shown) that manages the entire monitoring area such as a building. It may be a thing.

On the other hand, if any of the vertical and horizontal sizes of the foreign object is less than the predetermined size in step S810 (S810, No), it is determined that the foreign object is not an intruder and the process returns to step S801. Repeat the process.
Here, in step S810, the foreign object is determined to be an intruder when both the vertical and horizontal sizes of the foreign object are greater than or equal to a predetermined value. When is larger than a predetermined size, the foreign object may be determined as an intruder. Further, when the area of the foreign object is equal to or larger than a predetermined value, the foreign object may be determined as an intruder.

  In the above-described monitoring operation process, the distance to the foreign object is measured when it is determined that the foreign object is reflected in both the no-light-projecting and the difference images at the time of the light-projecting (step in FIG. 12). S804, Yes), but not limited thereto, the distance to the foreign object may be measured when it is determined that the foreign object appears in either the difference image at the time of no light projection or the difference image at the time of light projection. .

  In addition, as a criterion for intruder detection, the vertical and horizontal sizes of the foreign matter are determined to be equal to or greater than a predetermined value (step S810 in FIG. 12, Yes). One of the determination criteria is that the thickness in the depth direction of the foreign matter calculated from the difference between the maximum value and the minimum value of the distance L is not less than a predetermined value.

  As described above, the distance measuring apparatus according to the first and second embodiments is a combination of the photographing unit 2 and the light projecting unit 3 such as a commonly used camera with a projector without using special parts. With a simple configuration, the distance to the object to be measured can be measured based on the image of the object to be measured. In addition, if the distance measuring device according to the present invention is used, the small animal or the like and the intruder are accurately identified as in the intruder monitoring device according to the third embodiment, and the small animal or the like is mistaken for the intruder and is erroneously reported. An intruder monitoring apparatus that does not cause a problem can be configured at low cost.

DESCRIPTION OF SYMBOLS 1, 1 '... Distance measuring device, 2 ... Imaging | photography means, 3 ... Projection means, 4 ... Memory | storage part 5, 5' ... Control part, 51 ... Image acquisition means 52 ... Luminance acquisition means, 53 ... Distance calculation means, 54 ... Calculation information generation means, 55, 84 ... Communication interface, 6, 11 ... Operation display section, 7 ... Intrusion Person monitoring device, 8 ... processing unit, 81 ... foreign matter detection means, 82 ... foreign matter size calculation means, 83 ... alarm generating means, 9 ... data bus, 10 ... image storage unit , 12 ... Speakers.

Claims (9)

From the photographing means to the object to be measured, based on an image of the object to be photographed by projecting light from the light projecting means, having a photographing means and a light projecting means for projecting on the photographing field of view of the photographing means A distance measuring device that measures the distance of
Luminance acquisition means for acquiring the luminance of the image of the object to be measured when the light emission state of the light projecting means is the first light emission state and the second light emission state having a higher illuminance than the first light emission state. When,
Based on the luminance difference between the image of the object in the first light emitting state and the luminance difference between the image of the object in the first and second light emitting states, measured in advance for each distance from the photographing unit, the first The distance from the photographing means to the object to be measured from the brightness of the image of the object to be measured acquired in the light emission state and the brightness difference between the images of the object to be measured acquired in the first and second light emission states. Calculating means for calculating
Ranging device having The distance measuring device according to claim 1,
Storage means for storing the brightness of the image of the object in the first light emission state and the brightness difference between the images of the object in the first and second light emission states, which are measured in advance for each distance from the photographing means. Ranging device having In the distance measuring device according to claim 1 or 2,
A distance measuring device in which a first light emission state of the light projecting means is a light-off state, and a second light emission state is a light-on state. A foreign object in the monitoring area is detected by detecting a foreign object in the monitoring area from a difference image between a background image when there is no foreign object in the monitoring area and a monitoring image for monitoring the entry of the foreign object into the monitoring area. An intruder monitoring device to detect,
A distance measuring device according to any one of claims 1 to 3,
Foreign object size calculating means for calculating the foreign object size from the distance from the imaging means measured by the distance measuring device to the foreign object and the size of the foreign object image in the difference image;
Alarm generating means for issuing an alarm when the foreign object size calculated by the foreign object size calculating means is equal to or larger than a predetermined size;
An intruder monitoring device. Intruder monitoring device according to claim 4,
The foreign object size calculation means is measured by the distance measuring device, based on a difference between a distance between the photographing means and the distance between the photographing means and a distance between the closest part and the photographing means. It has a function to calculate the thickness of foreign matter,
The alarm generation means is an intruder monitoring apparatus that further issues an alarm when the thickness of the foreign matter is equal to or greater than a predetermined thickness. In the intruder monitoring device according to claim 4 or 5,
The distance image is generated based on a background image and a monitoring image acquired when the light projecting unit is in a first light emission state. In the intruder monitoring device according to claim 4 or 5,
The distance image is generated based on the background image and the monitoring image acquired when the light projecting unit is in the second light emission state. From the photographing means to the object to be measured, based on an image of the object to be photographed by projecting light from the light projecting means, having a photographing means and a light projecting means for projecting on the photographing field of view of the photographing means A distance measuring method in a distance measuring device for measuring the distance of
Obtaining the luminance of the image of the object to be measured when the light emitting state of the light projecting unit is the first light emitting state and the second light emitting state having a higher illuminance than the first light emitting state,
Based on the luminance difference between the image of the object in the first light emitting state and the luminance difference between the image of the object in the first and second light emitting states, measured in advance for each distance from the photographing unit, the first The distance from the photographing means to the object to be measured from the brightness of the image of the object to be measured acquired in the light emission state and the brightness difference between the images of the object to be measured acquired in the first and second light emission states. Calculating
A distance measuring method. From the photographing means to the object to be measured, based on an image of the object to be photographed by projecting light from the light projecting means, having a photographing means and a light projecting means for projecting on the photographing field of view of the photographing means A distance measuring device computer that measures the distance of
Luminance acquisition means for acquiring the luminance of the image of the object to be measured when the light emission state of the light projecting means is the first light emission state and the second light emission state having a higher illuminance than the first light emission state. When,
Based on the luminance difference between the image of the object in the first light emitting state and the luminance difference between the image of the object in the first and second light emitting states, measured in advance for each distance from the photographing unit, the first The distance from the photographing means to the object to be measured from the brightness of the image of the object to be measured acquired in the light emission state and the brightness difference between the images of the object to be measured acquired in the first and second light emission states. Calculating means for calculating
Program to function as.

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