JP2018050164A - Imaging apparatus, control method of the same, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress influence on eyes while ensuring a monitoring function.SOLUTION: An imaging apparatus 1000 is capable of imaging a subject image in a mode of imaging with invisible light. In photographing in an infrared mode, in parallel with irradiation of infrared light 401 by an infrared illumination unit 210, a visible illumination unit 212 emits visible light 402 in a range of an irradiation range or wider of the infrared light 401 by the infrared illumination unit 210.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an imaging device that can perform imaging with invisible light.

  2. Description of the Related Art Conventionally, a monitoring camera including an infrared illumination device that irradiates infrared light that is invisible light is known as an imaging device for monitoring at night or in a dark place. This camera has the advantage of being able to monitor without being noticed even in the absence of visible light by turning on the infrared illumination. In recent years, there has been an increasing demand for surveillance cameras equipped with an infrared illumination device with increased illumination intensity in order to enable monitoring of farther subjects.

  There are also surveillance cameras with infrared and visible illumination. While shooting under infrared illumination is not noticeable by humans, it has the drawback that it is difficult to distinguish the characteristics of a person. In addition, while photographing under visible illumination is noticed by a person, there is an advantage that it is easy to distinguish the characteristics of a person. Therefore, Japanese Patent Application Laid-Open No. H10-228561 proposes a method of shooting an intruder with certain light emission by visible light while shooting with infrared illumination so that it is difficult for humans to notice.

JP 2001-275021 A JP 2012-11840 A

  However, there is a risk to the human body (especially the eyes) if infrared illumination is viewed directly for a long time. That is, when an infrared light source for illuminating a subject is turned on, if a person enters an infrared light irradiation range from outside the angle of view of imaging, there is a concern that the human body may be adversely affected. In particular, since infrared light cannot be visually recognized, there is a possibility that strong infrared light may be irradiated to the eye for a long time without noticing.

  By the way, since there exists a possibility of giving discomfort, such as glare, when illumination is too strong, patent document 2 has proposed the method of adjusting illumination intensity according to the distance with a to-be-photographed object. However, when performing far-field monitoring with infrared illumination, if the intensity of infrared light is adjusted by applying the technique of Patent Document 2, the irradiation intensity is appropriate when the subject appears in the vicinity. (Low) is adjusted so that Then, the illumination intensity to a distant place falls and it becomes difficult to monitor a distant place. That is, when the subject appears in the vicinity or the like, it is difficult to appropriately continue monitoring using infrared light while taking into account the suppression of risk to the human body.

  An object of this invention is to suppress the influence on eyes, ensuring a monitoring function.

  In order to achieve the above object, the present invention includes an imaging unit capable of imaging a subject image in a mode of imaging with invisible light, a first irradiation unit that irradiates the invisible light, and the first irradiation unit. In parallel with the irradiation of the invisible light, there is provided a second irradiation means for irradiating visible light over a wide range not less than the irradiation range by the first irradiation means.

  According to the present invention, it is possible to suppress the influence on the eye while securing the monitoring function.

It is a block diagram of an imaging system including an imaging device. It is a block diagram of an imaging device. It is a block diagram of a determination part. It is a figure (figure (a)) which shows signs that it irradiates only infrared light, and a figure (figure (b)) which shows signs that it irradiates infrared light and visible light. It is a flowchart of the illumination control in infrared light mode. It is a flowchart of the illumination control in infrared light mode.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of an imaging system including an imaging apparatus according to the first embodiment of the present invention. This imaging system includes an imaging apparatus 1000, and an imaging apparatus 1000 and an external apparatus client apparatus 2000 are connected to each other via a network 1500 so that they can communicate with each other. The client apparatus 2000 transmits various control commands to the imaging apparatus 1000. These control commands include, for example, commands for starting and stopping imaging, and illuminating the illumination device. In addition, the imaging apparatus 1000 that has received each control command transmits a response to the received control command to the client apparatus 2000.

  The imaging apparatus 1000 is an example of an imaging apparatus that has a predetermined angle of view and captures the subject 3000, and is, for example, a surveillance camera that captures a moving image. More specifically, it is assumed that the imaging apparatus 1000 is a network camera used for monitoring. The client device 2000 is an example of an external device such as a PC (personal computer). The network 1500 includes a plurality of routers, switches, cables, and the like that satisfy a communication standard such as Ethernet (registered trademark). However, as long as communication between the imaging apparatus 1000 and the client apparatus 2000 can be performed, the communication standard, scale, and configuration are not limited. For example, the network 1500 may be configured by the Internet, a wired LAN (Local Area Network), a wireless LAN (Wireless LAN), a WAN (Wide Area Network), or the like. Note that the imaging apparatus 1000 may support, for example, PoE (Power Over Ethernet (registered trademark)), and may be supplied with power via a LAN cable.

  FIG. 2 is a block diagram of the imaging apparatus 1000. An image of the subject 3000 (subject image) passes through the imaging optical system 200 and the infrared filter 201 and enters an imaging element 202 (imaging means) such as a CCD or CMOS sensor. In FIG. 2, the imaging optical system 200 is represented as a single lens, but may be configured by a plurality of lenses. The infrared filter 201 includes a plurality of filters such as an optical low-pass filter and an optical band-pass filter, and one or more of them may be arbitrarily selected. Further, the infrared filter 201 may be a dark filter that reduces the amount of incident light or a polarizing filter that blocks light in a predetermined polarization direction. The optical system control unit 206 performs mechanical driving related to focusing control, zoom control, exposure control, image stabilization control, and the like of the imaging optical system 200 according to instructions from the system controller 205. In addition, imaging conditions for imaging with a predetermined exposure such as an aperture value, a shutter speed, and a gain are determined by the system controller 205 based on a predetermined program diagram.

  The subject image formed on the image sensor 202 is converted into an image signal and input to the image processing unit 203. The image processing unit 203 performs predetermined image processing such as gamma correction and color balance adjustment on the input image to generate an image file such as JPEG. The system controller 205 performs a predetermined display process on the output image processed by the image processing unit 203 and displays the image on the display unit 204. The determination unit 207 is controlled by the system controller 205, analyzes the input image, and determines a lighting device control method based on the result. The device control unit 208 performs lighting control of the infrared illumination unit 210 (first irradiation unit) and the visible illumination unit 212 (second irradiation unit) provided in the imaging apparatus 1000 according to an instruction from the system controller 205. Specifically, the device control unit 208 controls the infrared illumination unit 210 using the first switching unit 209 and performs lighting control of the visible illumination unit 212 using the second switching unit 211. The device control unit 208 plays a role as control means in cooperation with the system controller 205. The filter control unit 213 performs insertion / extraction control of the infrared filter 201 provided in the imaging apparatus 1000 using the drive unit 214 in accordance with an instruction from the system controller 205.

  A system controller 205 includes a CPU 216 and a memory 217, and controls each component of the imaging apparatus 1000 and sets various parameters. The memory 217 is a memory that can electrically erase data, and stores a program executed by the system controller 205. The memory 217 is used as a program storage area executed by the system controller 205, a work area during program execution, a data storage area, and the like. In addition, the memory 217 holds initial values of various parameters that are setting information used by the system controller 205 to control the imaging apparatus 1000. In addition, the memory 217 includes a timing unit (not shown), and can perform timing such as a predetermined period at an arbitrary timing. The communication unit 215 receives each control command from the client apparatus 2000 and transmits a response to each control command and a video stream to the client apparatus 2000.

  The above is an example of the basic configuration of the imaging apparatus 1000. Here, in order to make the explanation easy to understand, the filter control unit 213 and the device control unit 208 are introduced, but these are eliminated and the system controller 205 is directly connected to the first switching unit 209, the second control unit 209, and the second control unit 208. You may connect to the switch part 211.

  FIG. 3 is a block diagram of the determination unit 207. The determination unit 207 includes a moving object detection unit 301, a time calculation unit 302, a distance calculation unit 303, an irradiated light amount calculation unit 304, and an accumulated light amount calculation unit 305. The moving object detection unit 301 detects a moving object from the entire screen or a part of the image input from the image processing unit 203, that is, determines the presence or absence of the moving object. When the moving object detection unit 301 detects a moving object, the time calculation unit 302 measures a staying time that is a period during which the moving object exists in the imaging range. The distance calculation unit 303 calculates the distance from the imaging apparatus 1000 to the moving object. The irradiated light amount calculation unit 304 is based on the intensity of the infrared light irradiated by the infrared illumination unit 210 and the distance calculated by the distance calculation unit 303 per unit time of the infrared illumination that the moving body is exposed to. Is calculated. The accumulated light amount calculating unit 305 is an accumulated infrared irradiation light amount that is accumulated by the moving body based on the stay time measured by the time calculating unit 302 and the irradiated light amount calculated by the irradiated light amount calculating unit 304. Calculate the amount of light.

  In the present embodiment, the infrared illumination unit 210 can irradiate infrared light that is invisible light. The visible illumination unit 212 can irradiate visible light having a wavelength different from the light emitted by the infrared illumination unit 210. The imaging apparatus 1000 has a plurality of imaging modes, can capture a subject image in an infrared light mode in which imaging is performed with infrared light, and can also capture a subject image in a visible light mode in which imaging is performed with visible light. In the present embodiment, visible light is irradiated in parallel with infrared light in the infrared light mode. 4A and 4B, a comparison between a conventional imaging mode that does not use visible light and the present embodiment will be described.

  FIG. 4A is a diagram illustrating a state in which imaging is performed by irradiating only infrared light in a conventional imaging apparatus. FIG. 4B is a diagram illustrating a state in which imaging is performed by irradiating infrared light and visible light in the infrared light mode according to the present embodiment.

  In the example of FIG. 4A, only the infrared light 401 (infrared illumination) is turned on, and the visible light 402 (visible illumination) is not turned on. The subject 3000 as a person cannot perceive the infrared light 401. Therefore, if the pupil 3001 of the eye of the subject 3000 is in a wide open state and the subject 3000 faces the direction of the imaging device 1000, the amount of incident infrared light 401 into the eye increases. From the viewpoint of health, it is not preferable to look directly at the infrared light 401 for a long time.

  In the example of FIG. 4B, infrared light 401 and visible light 402 are turned on. When the subject 3000 perceives visible light 402, the pupil 3001 of the eye contracts. Therefore, even if the intensity of the infrared light 401 remains the same, it is possible to expect an effect that the amount of the infrared light 401 entering the eye is reduced. Here, the irradiation range of the visible light 402 is greater than or equal to the irradiation range of the infrared light 401. Consider a case where a person (subject 3000) enters the field of view as a moving object from outside the field of view of the imaging apparatus 1000. Since the subject 3000 is irradiated with the visible light 402 before or after the subject 3000 enters the irradiation range of the infrared light 401, it is possible to promptly contract the iris of the eye of the subject 3000 at an early stage, and the pupil is large. The possibility of being exposed to infrared light in the open state can be reduced. Therefore, the amount of infrared light 401 incident on the eye can be suppressed, and the influence on the human body can be reduced.

  Note that it is desirable that the infrared light 401 has a high intensity that allows remote monitoring, and the visible light 402 has a low intensity that reaches near the imaging apparatus 1000. By doing so, the visible light 402 is hardly noticed by a distant person, so that it is possible to continuously acquire and monitor a distant image while reducing the influence on the nearby person. Further, the irradiation direction of the visible light 402 may be set so that the distance that the visible light 402 reaches is shorter than the infrared light 401.

  FIG. 5 is a flowchart of illumination control in the infrared light mode. The processing of this flowchart is realized by the CPU 216 reading and executing a program stored in the memory 217 included in the system controller 205 in the work area of the memory 217. This process is started when the start of the infrared mode is instructed. The start of the infrared mode is instructed by the user from an operation unit (not shown) or from the client device 2000 via the communication unit 215.

  First, in step S501, the system controller 205 (hereinafter sometimes abbreviated as “controller 205”) controls the device control unit 208 (FIG. 2) to turn on the infrared illumination unit 210 and the visible illumination unit 212. Let In step S501, the initial intensity of the infrared light emitted from the infrared illumination unit 210 and the initial intensity of the visible light emitted from the visible illumination unit 212 are determined in advance. In step S <b> 502, the controller 205 acquires a captured image (video) from the image processing unit 203 via the determination unit 207.

  Next, in step S503, the controller 205 controls the moving object detection unit 301 (FIG. 3) to detect the moving object in the image acquired from the image processing unit 203, and determines whether a moving object has been detected. Here, a human is assumed as a moving object to be detected. Based on the detection result of the moving object detection unit 301, the controller 205 returns the process to step S501 if it is not determined that a moving object has been detected, but proceeds to step S504 if it is determined that a moving object has been detected. In step S504, the controller 205 controls the time calculation unit 302 to start measuring the staying time T during which the moving object detected in step S503 stays in the imaging range.

  In step S505, the controller 205 uses the moving object detected in step S503 as a target (hereinafter, the target moving object is referred to as a subject 3000), and calculates a subject distance D that is the distance between the imaging apparatus 1000 and the target as a distance calculation unit. 303. At the same time, the controller 205 determines whether or not the subject distance D is less than or equal to the threshold value. Here, the calculation method of the distance to the object is not limited, and for example, a distance measurement mechanism (not shown) may be used. Further, the threshold value is the closest distance at which focusing is possible. Therefore, in the focus control of the imaging optical system 200, the determination in step S505 may be performed depending on whether the target focus position is in front of or behind the closest object. Then, if the calculated subject distance D exceeds the threshold value, the controller 205 is considered to be far away from the subject 3000 even within the angle of view and is not likely to be exposed to much infrared light. It returns to step S501. On the other hand, if the subject distance D is equal to or smaller than the threshold value, the subject 3000 is near and there is a risk of receiving a lot of infrared light, so the controller 205 advances the process to step S506.

  In step S506, the controller 205 controls the accumulated light amount calculation unit 305 to start calculating (estimating) the accumulated light amount of infrared light that the subject 3000 is exposed to. In the calculation of the accumulated light amount, at least the stay time T and the irradiated light amount per unit time calculated by the irradiated light amount calculation unit 304 are used. As described above, the intensity of infrared light and the subject distance D are used to calculate the amount of light to be irradiated. The longer the stay time T, the higher the intensity of infrared light, and the shorter the subject distance D, the greater the accumulated light quantity.

  In step S507, the controller 205 determines whether or not the calculated accumulated light amount exceeds a predetermined value (accumulated light amount> predetermined value is satisfied). Here, the predetermined value is set to a value sufficiently low so that the influence of the infrared illumination on the human eye is within an allowable range. If the accumulated light quantity> predetermined value is not satisfied, the influence on the eyes is small, and the controller 205 returns the process to step S501. Therefore, if the accumulated light quantity is within the predetermined value, the photographing with the infrared light turned on is continued. On the other hand, if the accumulated light quantity> predetermined value is satisfied, the influence on the eye increases when the infrared light irradiation is continued. Therefore, in step S508, the infrared illumination unit 210 is turned off and the infrared light irradiation is stopped. . Here, instead of turning off the infrared light, the intensity of the infrared light may be controlled to be lower than before. Thereafter, the process of FIG. 5 ends.

  According to the present embodiment, in photographing in the infrared mode, in parallel with the irradiation of the infrared light 401 by the infrared illumination unit 210, a wide range that is equal to or larger than the irradiation range of the infrared light 401 by the infrared illumination unit 210. The visible illumination unit 212 emits visible light 402. Thereby, the influence on eyes can be suppressed, ensuring a monitoring function.

  In addition, when the subject 3000 enters the angle of view as a moving object, the controller 205 measures the stay time T, and the subject 3000 bathes based on the stay time T, the intensity of the infrared light 401, and the subject distance D. Estimate the accumulated amount of infrared light. When the accumulated light quantity exceeds a predetermined value, the controller 205 lowers the intensity of the infrared light 401 (turns off) than before. Thereby, the integrated irradiation amount of the infrared light 401 can be suppressed and the eye can be protected.

  When the subject 3000 detected as a moving object moves out of the imaging range or moves to a position exceeding the threshold value, the calculation of the accumulated light amount may be temporarily stopped or may be initialized. When the calculation of the accumulated light quantity is once stopped, the controller 205 may determine whether or not the moving object that has entered the imaging range after that is the same as the moving object that has entered the previous time by image analysis or the like. If the same moving object is re-invading, the controller 205 may resume the calculation of the accumulated light quantity from the timed state where it is temporarily stopped.

(Second Embodiment)
In the second embodiment of the present invention, the illumination control process in the infrared light mode is different from that of the first embodiment. Therefore, the present embodiment will be described using FIG. 6 instead of FIG. 5 with respect to the first embodiment.

  FIG. 6 is a flowchart of illumination control in the infrared light mode. The execution conditions and start timing of the processing in this flowchart are the same as those in the flowchart of FIG. In step S601, the controller 205 controls the device control unit 208 to turn on the infrared illumination unit 210 and blink the visible illumination unit 212. In steps S602 to S605, the controller 205 executes the same processing as steps S502 to S505 in FIG. In step S606, the controller 205 switches the visible illumination unit 212 from blinking to lighting (always light emission), and the process proceeds to step S607.

  In steps S607 to S609, the controller 205 executes the same processing as in steps S506 to S508 in FIG. Next, in step S710, the controller 205 switches the imaging mode from the infrared light mode to the visible light mode that is the color imaging mode, and ends the processing of FIG.

  According to the present embodiment, the same effects as those of the first embodiment can be achieved with respect to suppressing the influence on the eyes while securing the monitoring function. Even if a moving object is detected, the visible illumination unit 212 is in a blinking state until the subject distance D is equal to or less than the threshold value, so that power consumption can be reduced. Moreover, when the subject distance D is equal to or smaller than the threshold value, the visible illumination unit 212 is turned on, so that the influence on the eyes of a person or the like at a short distance can be reduced. When the accumulated light quantity exceeds a predetermined value, the infrared illumination is turned off and then the color photographing mode is switched, so that it is possible to improve the near monitoring ability instead of reducing the distant monitoring ability.

  In the present embodiment, the timing of switching from blinking to lighting of the visible light 402 is after the subject distance D becomes equal to or less than the threshold value. However, if a moving object is detected in step S603, the visible light 402 may be switched to lighting. Note that the intensity of visible light 402 is initially switched to blinking and then turned on, but is not limited to this, and the emission intensity in step S606 may be higher than the emission intensity in step S601. .

  In each of the above embodiments, the intensity of the visible light 402 is fixed at a fixed value when calculating the accumulated light amount. However, the intensity of the visible light 402 may be configured to be variable, and the visible light intensity may be included as a parameter when calculating the accumulated light quantity. That is, the higher the visible light intensity, the smaller the pupil, so the amount of light to be irradiated per unit time becomes smaller. In consideration of this, the arithmetic expression may be set so that the increase rate of the accumulated light amount with the passage of time becomes smaller as the visible light intensity is higher. For example, when the visible light intensity is designated in advance by the user, it is conceivable to calculate the accumulated light quantity according to the designated visible light intensity. As an example in which the visible light intensity is variable, for example, it is conceivable that the visible light intensity is increased stepwise as the subject distance D decreases.

  In the above embodiments, the controller 205 controls the infrared illumination unit 210 and the visible illumination unit 212. However, the infrared illumination unit 210 and the visible illumination unit 212 may be controlled by remote operation from the client device 2000 via the network 1500. In other words, each control process described as being executed by the controller 205 may be performed from an external device such as the client device 2000. The invisible light is not limited to infrared light as long as it can be used for imaging.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program code. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. A part of the above-described embodiments may be appropriately combined.

202 Imaging device 210 Infrared illumination unit 212 Visible illumination unit 401 Infrared light 402 Visible light

Claims (15)

An imaging means capable of imaging a subject image in a mode of imaging with invisible light;
First irradiation means for irradiating the invisible light;
In parallel with the irradiation of the invisible light by the first irradiation means, there is provided a second irradiation means for irradiating visible light over a wide range not less than the irradiation range by the first irradiation means. An imaging device. Detecting means for detecting a moving object;
The imaging apparatus according to claim 1, further comprising a control unit that controls the second irradiation unit based on a detection result by the detection unit. Having an acquisition means for acquiring a distance to the moving object detected by the detection means;
The imaging apparatus according to claim 2, wherein the control unit controls the second irradiation unit based on the distance acquired by the acquisition unit.   When the acquired distance is less than or equal to a threshold value, the control means controls the intensity of the visible light emitted by the second irradiation means to be higher than before. The imaging apparatus according to claim 3.   The control unit blinks the visible light by the second irradiation unit in the mode of imaging with the invisible light, and when the acquired distance becomes equal to or less than the threshold value, the second irradiation unit causes the second irradiation unit to The imaging apparatus according to claim 4, wherein visible light is turned on. Detecting means for detecting a moving object;
Measuring means for measuring the time during which the moving object detected by the detecting means stays within the imaging range of the imaging means;
Obtaining means for obtaining a distance to the moving object;
6. A control unit that controls the first irradiation unit based on the time measured by the measurement unit and the distance acquired by the acquisition unit. The imaging apparatus according to item 1.   The control means estimates an integrated dose of the invisible light based on the measured time, the acquired distance, and the intensity of the invisible light emitted by the first irradiation means. When the estimated integrated irradiation amount exceeds a predetermined value, the intensity of the invisible light irradiated by the first irradiation unit is controlled to be lower than before. Item 7. The imaging device according to Item 6.   The control means turns on the invisible light by the first irradiation means in the mode for imaging with the invisible light, and the non-visible light is emitted by the first irradiation means when the integrated irradiation amount exceeds the predetermined value. The imaging apparatus according to claim 7, wherein visible light is turned off.   When the integrated irradiation amount exceeds the predetermined value, the control unit increases the intensity of the visible light irradiated by the second irradiation unit than before and increases the non-irradiation by the first irradiation unit. The imaging apparatus according to claim 8, wherein after the visible light is turned off, the imaging mode of the imaging unit is switched from the mode for imaging with the invisible light to the mode for imaging with the visible light.   The imaging apparatus according to claim 7, wherein the control unit estimates the integrated irradiation amount after the acquired distance becomes equal to or less than a threshold value.   11. The imaging apparatus according to claim 4, 5 or 10, wherein the threshold value is a closest distance that can be focused by the imaging unit.   The imaging apparatus according to claim 1, wherein the invisible light is infrared light. An imaging means capable of imaging a subject image in a mode of imaging with invisible light;
First irradiation means for irradiating the invisible light;
In parallel with the irradiation of the invisible light by the first irradiation unit, a second irradiation unit that irradiates visible light over a wider range than the irradiation range by the first irradiation unit. A method,
A method for controlling an imaging apparatus, comprising: detecting a moving object; and controlling the second irradiation unit based on a detection result. Measuring the time during which the detected moving object stays within the imaging range of the imaging means;
Get the distance to the moving object,
The method for controlling the imaging apparatus according to claim 13, wherein the first irradiation unit is controlled based on the measured time and the acquired distance.   A program for causing a computer to execute the method for controlling an imaging apparatus according to claim 13 or 14.

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