JP2023175404A - Imaging apparatus, control method for the same, and program - Google Patents

Abstract

To provide excellent illumination control in an imaging apparatus including an illumination unit.SOLUTION: An imaging apparatus has an illumination unit that illuminates an imaging area with illumination light, an imaging unit rotatable either around an axis in a first direction or around an axis in a second direction orthogonal to the first direction, an optical filter switchably arranged in the imaging unit, and control means for switching between a first mode in which imaging is performed with the optical filter inserted and a second mode in which imaging is performed with the optical filter retracted. The control means acquires an angle in the first direction or the second direction of the imaging unit when the mode is switched to the second mode and the illumination unit is irradiating the imaging area with illumination light, determines a portion of the area in the image captured by the imaging unit as an area to be corrected on the basis of the acquired angle, and corrects the luminance value in the area to be corrected on the basis of the angle.SELECTED DRAWING: Figure 2

Description

The present invention relates to an imaging device, a method of controlling the imaging device, and a program.

Network cameras have traditionally been used as one of the security measures. The network camera has a day mode function that places an IR cut filter in front of the image sensor to capture only visible light and captures images, and a day mode function that captures infrared light by removing the IR cut filter to improve visibility in low-light environments. There are products that have a night mode feature that improves the performance. Furthermore, there are products in which a network camera is equipped with an infrared illumination device (infrared illumination unit) in order to take brighter images when photographing in night mode.

However, when photographing in a low-light environment using the above configuration, a problem arises in that the photographed image does not have uniform brightness depending on the irradiation range of the infrared illumination light. For example, in the imaging device described in Patent Document 1, it is determined whether or not the subject is illuminated, and if the illumination is used, the imaging device corrects the peripheral light falloff caused by the illumination. A configuration is disclosed that makes the brightness of an image uniform.

Japanese Patent Application Publication No. 2015-195499

However, the configuration of Patent Document 1 is effective when the photographing direction and the irradiation direction of the infrared illumination light are in the same direction, but does not take into consideration the case where they are in different directions. For example, if the imaging unit has a configuration that allows rotation such as panning and tilting (hereinafter referred to as PT), the infrared illumination device may be separated from the imaging unit to reduce the size of the imaging unit and prevent heat. The irradiation direction of the infrared illumination light is fixed. Therefore, depending on the PT angle of the imaging unit, the shooting direction and the irradiation direction of the infrared illumination may diverge, and a brightness difference may occur between the area within the irradiation range of the infrared illumination light and the area outside the irradiation range within the captured image. Put it away.

Therefore, an object of the present invention is to perform good illumination control in an imaging device equipped with an illumination section.

In order to achieve the above object, an imaging device according to one aspect of the present invention includes an illumination unit that irradiates illumination light onto an imaging region, a region around an axis in a first direction, and a region around an axis in a first direction. an imaging section that is rotatable in at least one of the directions around an axis in a second direction orthogonal to the imaging section; an optical filter that is switchably disposed on the imaging section; mode and a second mode in which imaging is performed with the optical filter retracted. Obtaining the angle of the first direction or the second direction of the imaging unit when irradiating the image, and based on the obtained angle, determining a part of the area in the image captured by the imaging unit as the correction target area, The method is characterized in that the brightness value in the correction target area is corrected based on the angle.

According to the present invention, it is possible to perform good lighting control in an imaging device including an illumination section.

1 is a block diagram showing a configuration example of an imaging device according to a first embodiment. FIG. FIG. 2 is a diagram illustrating a configuration example of an imaging device in a case where the tilt angle of the imaging unit is 45° according to the first embodiment. 3 is a diagram showing an image that can be obtained when the tilt angle of the imaging unit according to the first embodiment is 45 degrees. FIG. FIG. 2 is a block diagram illustrating a configuration example of an imaging device in a case where the tilt angle of the imaging unit is 90° according to the first embodiment. 3 is a diagram showing an image that can be obtained when the tilt angle of the imaging unit according to the first embodiment is 90 degrees. FIG. 7 is a flowchart showing processing according to the first embodiment. FIG. 3 is a diagram showing the relationship between the tilt angle of the imaging unit and the correction target area according to the first embodiment. FIG. 7 is a diagram showing images before and after contrast correction for an image acquired when the tilt angle of the imaging unit according to the first embodiment is 90 degrees. 7 is a flowchart illustrating an example according to Embodiment 2. FIG. FIG. 7 is a diagram showing an image according to Embodiment 2 and a changed correction target area. 7 is a flowchart showing processing according to Embodiment 3. FIG. 7 is a diagram showing an image according to Embodiment 3 and a changed correction target area.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is an example of means for realizing the present invention, and should be modified or changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. It is not limited to. Moreover, a part of each embodiment described later may be combined as appropriate.

<Embodiment 1>
The imaging device 100 of Embodiment 1 has an infrared light imaging function (night mode function) that improves visibility in a low-light environment by capturing infrared light, and a shooting angle of view (angle of view of the camera). The present invention is an imaging device equipped with an infrared illumination mechanism that can illuminate an imaging range with infrared light. An example of an imaging device having a night mode function and an infrared illumination unit is a surveillance camera (network camera, security camera, etc.). In the description of the first embodiment, an example will be given in which the imaging device 100 is equipped with an infrared illumination mechanism (infrared illumination unit); It may also have a different configuration.

FIG. 1 is a block diagram showing a configuration example of an imaging device 100 according to the first embodiment. Note that FIG. 1 shows only the main parts of the components, and other components are omitted. The imaging device 100 in Embodiment 1 takes in light from the outside, captures an image (captures an optical image of a subject, etc.), generates an image signal, and displays the generated image signal on an image display unit 105, a server (not shown), etc. can be distributed to external devices. In the first embodiment, the imaging device 100 and the image display unit 105 are configured as separate bodies, and the imaging device 100 and the image display unit 105 are communicably connected. The image display section 105 may be configured integrally.

The imaging device 100 in the first embodiment may include an imaging section 101, an image signal processing section 102, a communication section 103, a system control section 104, an infrared illumination section 106, a rotation control section 107, and a main body section 108.

The imaging unit 101 acquires an image by capturing light from the outside and capturing an image, thereby generating an image signal of a surrounding subject. The imaging unit 101 is attached (arranged) to the main body 108 of the imaging device 100 . Further, the imaging unit 101 includes a lens group (not shown), an IRCF (Infrared Ray Cut Filter) that is an optical filter, an image sensor, a CDS circuit, an AGC amplifier, an A/D converter, and the like. Further, in order to change the imaging direction, the imaging unit 101 rotates (pan rotation) in a horizontal direction (panning direction, first direction) with respect to a rotation axis (rotation axis) and vertically in a direction perpendicular to the rotation axis. It is configured to be rotatable (tilt rotation) in a direction (tilt direction, second direction). The imaging unit 101 includes a drive unit (not shown) that can change the orientation of the imaging unit 101 by rotating at least one of the horizontal axis and the vertical axis. .

The lens group is arranged on the front side (on the subject side) of the IRCF, and forms an optical image of the subject etc. on the image sensor. The IRCF includes an infrared light removal filter (IR cut filter) that is placed in front of the image sensor and that transmits visible wavelength light and blocks near-infrared wavelength light from the light that passes through the lens group. The image sensor is composed of an image sensor such as a CCD sensor or a CMOS sensor, and photoelectrically converts a subject image formed by a lens group and outputs it as an analog image signal. Furthermore, the imaging unit 101 has a configuration that allows the IRCF to be moved outside the light flux by the lens group, and when the IRCF is moved (evacuated) to the outside of the light flux by the lens group, the imaging unit 101 captures infrared light. It becomes possible.

In this way, the imaging device 100 of the first embodiment is capable of capturing only visible light when the IRCF is inserted into the imaging unit 101, and capturing infrared light when the IRCF is retracted. becomes. That is, the imaging device 100 has a visible light imaging function (day mode function) that captures only visible light to take an image, and an infrared light imaging function (night mode function) that captures infrared light to improve visibility in low-light environments. mode function) can be switched.

A CDS (Correlated Double Sampling) circuit performs correlated double sampling processing on an electrical signal input from an image sensor. The AGC (Automatic Gain Control) amplifier performs amplification processing and the like on the electrical signal input from the CDS circuit.

The A/D converter converts the analog signal amplified by the AGC amplifier into a digital signal. The image signal processing unit 102 performs image signal processing such as WB (white balance) processing and NR (noise reduction) processing on the digital signal converted and output by the imaging unit 101.

Although not shown, the system control unit 104 includes a CPU (Central Processing Unit), a ROM (Read-Only Memory), and a RAM (Random Access Memory). The CPU is composed of at least one computer, controls each functional block of the imaging device 100 and performs necessary calculations for the purpose, according to a program loaded from the ROM, and functions as a control means for controlling the imaging device 100 in an integrated manner. . The ROM (memory) stores control programs executed by the CPU and various constant values necessary for executing the programs. The programs stored in the ROM include programs according to each embodiment for controlling the drive of the imaging device 100, controlling the infrared illumination unit 106, and performing various calculations necessary therefor. Note that the CPU in the system control unit 104 may transmit a control signal to the rotation control unit 107 to control the rotation control unit 107. RAM (memory) is an area for storing various temporary data necessary for executing programs.

The communication unit 103 distributes the image signal processed by the image signal processing unit 102 to an external client device such as the image display unit 105, a server, etc. by wire or wirelessly. The output destination of the image signal may be an LCD (Liquid Crystal Display) built into the camera or an external display. Further, control information for the imaging apparatus 100 instructed from an external terminal including the image display unit 105 is acquired.

The infrared illumination unit 106 is an irradiation device that irradiates an imaging region or a subject with illumination light, and specifically, irradiates infrared illumination light (infrared light). By being disposed within the main body 108 of the imaging device 100, it is mounted on the main body 108. The infrared illumination unit 106 emits infrared illumination light based on the program of the system control unit 104 when the imaging unit 101 moves the IRCF out of the light flux by the lens group and transitions to night mode (second mode). irradiates the imaging area (imaging range) of the imaging unit 101.

Further, the infrared illumination unit 106 has a configuration that allows adjustment of the irradiation intensity of the infrared illumination light. The emission and irradiation intensity of the infrared illumination light in the infrared illumination unit 106 is controlled by the system control unit 104. For example, the system control unit 104 can control the irradiation intensity of the infrared illumination light by changing the drive current to an infrared light emitting unit (not shown) in the infrared illumination unit 106. That is, when the imaging apparatus 100 is set to night mode, the system control unit 104 functions as a means for moving the IRCF of the imaging unit 101 out of the light flux of the lens group to enable infrared light to be taken in. Note that the system control unit 104 also controls movement of the IRCF into the light beam of the lens group so that the imaging apparatus 100 changes from the night mode to the day mode (first mode).

The rotation control unit 107 is constituted by at least one computer, including a CPU, a memory (storage unit), etc., and performs drive control of the imaging unit 101 by controlling a drive unit (not shown). Specifically, a rotation control signal is output to the drive unit to drive the imaging unit 101 in the panning direction or in the tilting direction. The control signal output by the rotation control unit 107 includes information such as the drive angle, the amount of movement, and the rotation speed. The main body section 108 is a casing to which the imaging section 101 and the infrared illumination section 106 are attached as described above, and in which each functional section of the imaging device 100 is mounted.

The image display unit 105 is configured with an information processing device such as an external client device (PC) or a server that acquires the image signal subjected to the image processing described above via the communication unit 103 and displays the image. That is, the image display unit 105 is configured as part of an external terminal that can issue control instructions to the imaging device 100. In this case, the image display unit 105 includes a CPU, ROM, RAM, etc. that have the same functions as those described above. Furthermore, it is configured to include a display unit that displays images acquired via the communication unit 103, and an operation unit that includes a keyboard and a mouse that are operated by the user. The computer may also include a hard disk (HDD) for storing various electronic data and programs.

Further, the image display unit 105 may be a touch panel, a screen on a PC, or the like, and an instruction to the imaging device 100 may be generated based on an operation on the image display unit 105. Note that the image display unit 105 may be a simple CRT display or a monitor device such as a liquid crystal display.

First, the configuration of the imaging apparatus 100 according to the first embodiment will be described below with reference to FIGS. 2, 3, 4, and 5. FIG. 2 is a diagram showing a configuration example of the imaging apparatus 100 when the tilt angle of the imaging unit 101 is located at 45 degrees. Specifically, the imaging angle of view of the imaging unit 101 when the imaging apparatus 100 transitions to night mode and the system control unit 104 controls the lighting of the infrared illumination unit 106 in the normal infrared illumination state is as follows. FIG. 3 is a diagram showing a relationship with an irradiation range 300 of infrared illumination light. Note that in the first embodiment, the normal infrared illumination state is a state in which the irradiation intensity of the infrared illumination unit 106 is adjusted so that the infrared illumination light is irradiated as evenly as possible within the imaging angle of view of the imaging device 100. It is in a state of

FIG. 3 is a diagram showing an image 510 captured in the state shown in FIG. 2. Specifically, it is a diagram showing an example of an image 510 captured when the imaging device 100 is in a night mode and the infrared illumination unit 106 is in a normal infrared irradiation state in a low-light environment. Further, when the imaging device 100 is a surveillance camera, it often shoots a moving image, so the image 510 shown in FIG. 3 is assumed to be a one-frame image forming a moving image.

The imaging unit 101 in the first embodiment is attached to the main body 108 in a configuration that allows rotation (rotation) in the panning direction and the tilting direction, as described above. On the other hand, the infrared illumination section 106 is mounted on the main body section 108 in a non-rotatable configuration. As described above, since the imaging unit 101 is configured to be rotatable in both the panning direction and the tilting direction, the imaging range (imaging range) 200, which is the angle of view of the camera (imaging angle of view), is variable. Further, since the infrared illumination unit 106 cannot be rotated in any direction as described above, the irradiation range 300 of the infrared illumination light is limited to some extent. Therefore, although the imaging range 200 of the imaging unit 101 is variable, the irradiation range 300 of the infrared illumination light is fixed.

In the first embodiment, when the tilt angle of the imaging unit 101 is positioned at 45°, the deviation between the imaging range 200 of the imaging unit 101 and the irradiation range 300 of the infrared illumination light irradiated by the infrared illumination unit 106 is the smallest. (small) condition. When an image is captured in this state, there is less discrepancy between the irradiation range of the infrared illumination unit 106 and the imaging range 200 of the imaging unit 101, resulting in an image that is brighter overall and has improved visibility compared to the case when the image is captured in day mode. . That is, an image (captured image) with high uniformity of brightness can be obtained.

In the image 510 shown in FIG. 3, the person 10 and the person 20 existing within the photographing range 200 of the imaging unit 101 are respectively visible. Note that in a low-light environment, if the imaging device 100 is not set to night mode, the image captured by the imaging unit 101 will be a very dark image overall. In this state, even if the person 10, person 20, etc. are present within the photographing range 200 of the imaging unit 101, the image will be dark and hard to see, making it difficult to visually recognize these subjects.

FIG. 4 is a diagram showing an example of the configuration of the imaging apparatus 100 when the tilt angle of the imaging unit 101 is located at 90 degrees. Note that, similarly to FIG. 2, FIG. 4 shows a diagram of the imaging unit 101 when the imaging apparatus 100 transitions to night mode and the system control unit 104 controls the lighting of the infrared illumination unit 106 in the normal infrared illumination state. 3 is a diagram showing a relationship between a photographing angle of view and an irradiation range 300 of infrared illumination light. FIG.

FIG. 5 is a diagram showing an image 520 captured in the state shown in FIG. 4. Note that, similarly to FIG. 3, FIG. 5 shows an example of an image 520 captured when the imaging device 100 is in the night mode in a low-light environment and the infrared illumination unit 106 is in the normal infrared irradiation state. FIG. Furthermore, it is assumed that the image 520 shown in FIG. 3 shows one frame of an image constituting a moving image similarly to FIG.

In the first embodiment, when the tilt angle of the imaging unit 101 is located at 90°, the deviation between the imaging range 200 of the imaging unit 101 and the irradiation range of the infrared illumination light irradiated by the infrared illumination unit 106 is greatest ( large) state. If an image is captured in this state, the discrepancy between the irradiation range 300 of the infrared illumination unit 106 and the imaging range 200 of the imaging unit 101 becomes large. Therefore, as shown in FIG. 5, the irradiation range 300 of the infrared illumination light emitted by the infrared illumination unit 106 is located in the upper region of the image 520 with respect to the imaging range 200 of the imaging unit 101. There is non-uniformity in brightness. In the example of image 520 in FIG. 5, the upper region within the irradiation range 300 of the infrared illumination light is bright, but it becomes darker as it goes from near the edge of the irradiation range 300 of the infrared illumination light to the lower region. It is in a state of being. In this state, the person 10 existing within the photographing range 200 of the imaging unit 101 can be visually recognized, but it may be difficult to visually recognize the person 20.

FIG. 6 is a flowchart showing processing in the first embodiment. Hereinafter, with reference to FIG. 6, an example of image processing when infrared illumination light is irradiated in the imaging device 100 according to the first embodiment in consideration of the above-described problem will be described. Note that the flowchart in FIG. 6 illustrates a processing procedure executed by controlling each processing block by the system control unit 104. In the flowchart of FIG. 6, the program stored in the ROM of the system control unit 104 is expanded to the RAM and executed by the CPU.

When the imaging environment of the imaging device 100 becomes a low-light environment, that is, the illuminance is less than or equal to a predetermined value, the imaging device 100 transitions from day mode to night mode in step S600. Note that the transition to the night mode is not limited to the fact that the photographing environment has become a low-light environment; for example, the imaging device 100 can be transitioned to the night mode based on the fact that the current time has become night time. Good too. Alternatively, the imaging device 100 may be transitioned to night mode in response to a user operation or the like.

Next, in step S601, it is determined whether or not the infrared illumination unit 106 is to be used (to emit light). When using the infrared illumination unit 106, the system control unit 104 controls the infrared illumination unit 106 to emit infrared illumination light, and proceeds to step S602. On the other hand, if the infrared illumination unit 106 is not used, the process of this flow is ended and photography continues in night mode.

Next, in step S602, the rotation control unit 107 obtains a PT (pan/tilt) angle (rotation angle) of the imaging unit 101 while the infrared illumination unit 106 is emitting infrared illumination light. Note that the acquisition of the PT angle may be performed by the system control unit 104.

Next, in step S603, a part of the image acquired by the imaging unit 101 is determined as a contrast correction target area (hereinafter referred to as a correction target area) 400 based on the PT angle acquired in step S602. The correction target area 400 will be described below with reference to FIG. 7. Note that the system control unit 104 preferably determines a partial area of the image acquired by the imaging unit 101 as the correction target area 400 in conjunction with the timing at which the PT angle is acquired.

FIG. 7 is a diagram showing the relationship between the tilt angle of the imaging unit 101 and the correction target area 400 according to the first embodiment. According to the first embodiment, when the tilt angle is 0° and when the tilt angle is 90°, the direction of the photographing range 200 of the imaging unit 101 and the irradiation range 300 of the infrared illumination light are the most distant. Therefore, in the first embodiment, starting from the time when the tilt angle is 45 degrees, the contrast correction target area of the tilt angle that is farthest from the tilt angle of 45 degrees is made the largest. Furthermore, the correction target area 400 is gradually made smaller as the tilt angle approaches 45 degrees from the farthest tilt angle. In this case, the farthest tilt angles are 0° and 90° as described above.

Note that the size of the correction target area 400 shown in FIG. 8 is an example. Therefore, the size of the correction target area 400 shown in FIG. 8 is not limited to this, and may be set at any time depending on the performance and structure of the network camera (shooting range of the camera, irradiation range of infrared illumination light, etc.). I can do it.

Further, in the first embodiment, the correction target area 400 is determined in conjunction with the tilt angle, but the correction target area 400 may be determined based on the pan angle. Furthermore, the correction target area 400 may be determined based on each of the tilt angle and the pan angle.

Returning to FIG. 6, in step S604, contrast correction is performed on the correction target area 400 determined in step S603, and the process ends. Specifically, by applying digital gain to the low luminance area, the luminance value is increased and the contrast is corrected.

FIG. 8 is a diagram showing images before and after contrast correction for an image 520 acquired when the tilt angle of the imaging unit 101 is 90 degrees according to the first embodiment. FIG. 8A is a diagram showing an image 520 obtained before contrast correction and when the tilt angle of the imaging unit 101 is 90°. FIG. 8B is a diagram showing an image 530 after contrast correction for an image obtained when the tilt angle of the imaging unit 101 is 90 degrees. As shown in FIG. 8, by performing contrast correction on a predetermined correction target area, the image 530 becomes brighter overall and has improved visibility compared to the case where no contrast correction is performed. That is, an image (captured image) with high uniformity of brightness can be obtained.

In the first embodiment, the brightness value of the low brightness area is increased by contrast correction, but other methods such as dark area correction may be used as long as the process increases the brightness value of the low brightness area. Depending on the correction method, a brightness level difference may occur after correction at the boundary between the correction target area 400 and a non-target area that is a different area from the correction target area 400. Therefore, for example, a correction method may be used in which the correction amount of the brightness value is gradually changed from the non-correction target area to the correction target area 400.

Further, the correction target area 400 or the above correction amount may be changed depending on the dimming level (irradiation intensity) of the infrared illumination light emitted by the infrared illumination unit 106. Note that the contrast correction may be performed on the correction target area by changing each of the correction target area 400 and the above-mentioned correction amount.

As described above, according to the imaging device 100 of the first embodiment, even in a shooting environment where the shooting range 200 of the imaging unit 101 and the direction of the irradiation range 300 of the infrared illumination light irradiated by the infrared illumination unit 106 are different, images can be captured. This makes it possible to take images that are brighter overall and have improved visibility.

<Embodiment 2>
In the first embodiment, by performing contrast correction on a partial area of the acquired image based on the PT angle of the imaging unit 101, when there is a large deviation in direction between the imaging range of the imaging unit 101 and the irradiation range of the infrared illumination unit 106. It also made it possible to obtain images with improved visibility. Here, when the imaging unit 101 has an optical zoom function, the angle of view changes depending on the zoom magnification (focal length position), and the intended result may not be obtained.

Therefore, as a second embodiment, a case will be described in which the imaging unit 101 has an optical variable magnification (optical zoom) function by driving a zoom lens. Note that the configuration of the imaging device 100 is the same as that in Embodiment 1 except that the imaging unit 101 has an optical zoom function, and therefore the description thereof will be omitted.

FIG. 9 is a flowchart showing processing in the second embodiment. Hereinafter, with reference to FIG. 9, an example of image processing when infrared illumination light is irradiated in the imaging device 100 according to the second embodiment will be described. Note that the flowchart in FIG. 9 illustrates a processing procedure executed by controlling each processing block by the system control unit 104. In the flowchart of FIG. 9, the program stored in the ROM of the system control unit 104 is expanded to the RAM and executed by the CPU. Note that the same steps as those in the flowchart shown in FIG. 6 are given the same step numbers, and detailed explanation thereof will be omitted.

First, the processes from step S600 to step S603 are performed in the same manner as in the first embodiment. Each of these processes is the same as in Embodiment 1, so description thereof will be omitted. Next, in step S900, the system control unit 104 acquires the zoom position of the optical zoom of the imaging unit 101. Note that any method may be used as long as the zoom position of the imaging unit 101 is obtained. For example, zooming may be performed using position information obtained by dividing the area from the WIDE end to the TELE end into multiple parts, focal length information used in lens control, etc. You may also obtain the location.

Next, in step S901, the system control unit 104 changes the correction target area 410 determined in step S603 based on the zoom position obtained in step S900. By performing this process, a new correction target area can be determined from the correction target area 410 determined in step S603. Note that the system control unit 104 preferably changes the correction target area 410 determined in step S603 in conjunction with the timing at which the zoom position is acquired.

Note that when the imaging unit 101 has an optical zoom function, the imaging range 200 of the imaging unit 101 changes depending on the zoom magnification (focal length position), so the proportion of the irradiation range 300 of the infrared illumination light in the image increases. The correction target area that requires contrast correction becomes smaller. Next, the process advances to step S604, and the same processing as in the first embodiment is performed.

FIG. 10 is a diagram showing an example of a zoomed image 540 and a changed correction target area. As shown in FIG. 10, with respect to the correction target area 410 determined in step S603, the new correction target area 420 after the change has a smaller range (area) than the correction target area 410. Thereby, it is possible to reduce the area to be corrected and to perform appropriate contrast correction even when the photographing range changes depending on the zoom magnification. The amount of change in the correction target area 420 is just an example, and can be set arbitrarily, and may be set at any time depending on the performance and structure of the network camera (shooting range of the camera, irradiation range of infrared illumination light, etc.). can do.

As described above, according to the imaging device 100 of the second embodiment, even when the imaging unit 101 has an optical zoom function and the shooting range changes depending on the zoom magnification, the overall image can be improved by appropriate contrast correction. This allows you to obtain brighter images with improved visibility.

Note that in the second embodiment, the correction target area 410 is changed based on the zoom position in the imaging unit 101, but the correction amount of the brightness value for correcting the correction target area, not the correction target area, is changed. It may be configured as follows. Further, a configuration may be adopted in which the correction amount is changed while changing the correction target area based on the zoom position in the imaging unit 101.

<Embodiment 3>
If the subject is nearby in the image captured by the imaging unit 101, the degree of irradiation of the subject with infrared illumination light may change, and the intended result may not be obtained. Therefore, in Embodiment 3, processing in the imaging apparatus 100 when a subject is nearby will be described. Note that, in the configuration of the imaging device 100 of the third embodiment, the imaging unit 101 has a distance measuring device (distance measuring unit) such as a sensor that measures distance. The second embodiment is the same as the first embodiment except that the imaging unit 101 includes a distance measuring device (not shown) for measuring distance, and thus the description thereof will be omitted.

The distance measuring device in Embodiment 3 functions as a distance measuring device that measures distances to various objects (subject distances from the imaging device) captured within the imaging angle of view of the imaging device 100. In the third embodiment, the distance information acquired by the distance measuring device includes a plurality of pieces of distance information to various objects such as walls and floors reflected within the shooting angle of view of the imaging device 100.

FIG. 11 is a flowchart showing processing in the third embodiment. Hereinafter, with reference to FIG. 11, an example of image processing when infrared illumination light is irradiated in the imaging device 100 according to the third embodiment will be described. Note that the flowchart in FIG. 11 illustrates a processing procedure executed by controlling each processing block by the system control unit 104. In the flowchart of FIG. 11, the program stored in the ROM of the system control unit 104 is expanded to the RAM and executed by the CPU. Note that the same steps as those in the flowchart shown in FIG. 6 are given the same step numbers, and detailed explanation thereof will be omitted.

First, the processes from step S600 to step S603 are performed in the same manner as in the first embodiment. Each of these processes is the same as in Embodiment 1, so description thereof will be omitted. Next, in step S1100, the system control unit 104 divides the image acquired by the imaging unit 101 into a plurality of regions, and measures the subject distance for each divided region using a distance measuring device such as a sensor included in the imaging device 100. , obtain object distance information for each object. As the sensor for measuring the object distance, for example, a distance sensor or a phase difference image sensor may be used, and any method can be used as long as it is possible to measure the object distance. It's okay.

Next, in step S1101, the system control unit 104 changes the correction target area determined in step S603 based on the subject distance information acquired in step S1100. Note that it is preferable that the system control unit 104 change the correction target area determined in step S603 in conjunction with the timing at which the subject distance information is acquired.

In this process, within the correction target area, an area where there is a subject whose distance between the imaging device 100 and the subject is close, that is, a subject whose distance from the imaging device 100 is equal to or greater than a predetermined threshold, is removed from the correction target area. exclude. Next, the process advances to step S604, and the same processing as in the first embodiment is performed. On the other hand, an area where a subject whose distance from the imaging device is less than a predetermined threshold exists is not excluded from the correction target area. By performing this process, a new correction target area 440 can be determined from the correction target area determined in step S603.

The threshold value of the object distance from the imaging device to the object, which is the target of changing the correction target area, can be set arbitrarily, and it can be set arbitrarily depending on the performance and structure of the network camera (the shooting range of the camera, the irradiation range of infrared illumination light, etc.) can be set at any time.

FIG. 12 is a diagram illustrating an example of an image 550 in which a part of the correction target area is excluded based on subject distance information. In the image 550 shown in FIG. 12, the subject distance of the person 10 and the person 20 from the imaging device 100 is less than a predetermined threshold, so the area where the person 10 and the person 20 are present is not excluded from the correction target area. On the other hand, since the subject distance of the person 30 from the imaging device 100 is greater than or equal to the predetermined threshold, the area 430 where the person 30 exists is excluded from the correction target area. Thereby, the correction target area 440 can be determined as a new correction target area after the change excluding the excluded area 430.

Note that when dividing an image into multiple areas, the system control unit 104 can divide the image into any area, for example, divide the image into 8 areas of the same size, or divide the image into 16 areas. It is sufficient if the area can be divided into two or more areas. The areas to be divided can be set at any time depending on the performance and structure of the network camera (the shooting range of the camera, the irradiation range of infrared illumination light, etc.).

Furthermore, the system control unit 104 first detects a person in the image without dividing the image into multiple regions. After that, if the detected person's object distance from the imaging device 100 is equal to or greater than a predetermined threshold and the person exists within the correction target area, the surrounding area of the person is excluded from the correction target area. You can also do this. Note that the area surrounding the person to be excluded from the correction target area may be an area surrounded by a rectangular or circular frame around the person, or may be an area along the outline of the person.

As described above, according to Embodiment 3, even if the subject is nearby in the image, it is possible to obtain an image in which the image is bright overall and has improved visibility through appropriate contrast correction. can.

In the third embodiment, the correction target area is changed based on the subject distance measured by the distance measuring device included in the imaging device 100, but the correction amount of the brightness value for correcting the correction target area is changed instead of the correction target area. It is also possible to have a configuration that changes the . Further, a configuration may be adopted in which the correction amount is changed while changing the correction target area based on the zoom position in the imaging unit 101.

In the third embodiment, the imaging device 100 is configured to have a distance measuring device capable of measuring distance, but the present invention is not limited to this, and for example, the distance measuring device may be arranged separately from the imaging device 100. . In that case, it is only necessary to connect to the imaging device 100 via a wired or wireless line. Further, in each of the embodiments described above, the case where there is one infrared illumination unit 106 has been described, but the present invention is not limited to this, and a plurality of infrared illumination units may be arranged in the imaging device 100.

The disclosure of this embodiment includes the following configuration, method, and program.
(Configuration 1)
an illumination unit that irradiates the imaging area with illumination light;
an imaging unit rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
an optical filter that is switchably arranged in the imaging section;
a control means for switching between a first mode of imaging with the optical filter inserted and a second mode of imaging with the optical filter retracted; and the control means switched to the second mode. obtaining the angle of the first direction or the second direction of the imaging unit when the illumination unit is emitting illumination light to the imaging area;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
An imaging device characterized in that a brightness value in a correction target area is corrected based on an angle.

(Configuration 2)
The imaging device according to configuration 1, wherein the control unit determines a part of the area in the image captured by the imaging unit as the correction target area in conjunction with the timing at which the angle is acquired.

(Configuration 3)
3. The imaging device according to configuration 1 or 2, wherein the control means gradually changes the amount of correction of the luminance value in the correction target area from the correction target area to an area different from the correction target area.

(Configuration 4)
4. The imaging device according to any one of configurations 1 to 3, wherein the control means changes the correction target area based on the irradiation intensity of the illumination light.

(Configuration 5)
4. The imaging device according to any one of configurations 1 to 3, wherein the control means changes the amount of correction of the brightness value in the correction target area based on the irradiation intensity of the illumination light.

(Configuration 6)
The imaging unit has a zoom lens,
Any one of configurations 1 to 5, wherein the control means changes the correction target area from the correction target area determined by the control means to a new correction target area based on the zoom magnification of the zoom lens. The imaging device according to item 1.

(Configuration 7)
The imaging unit has a zoom lens,
6. The imaging device according to any one of configurations 1 to 5, wherein the control means changes the amount of correction of the brightness value in the correction target area based on the zoom magnification of the zoom lens.

(Configuration 8)
comprising distance measuring means for measuring the distance from the imaging device to the subject for each of the plurality of regions in the image captured by the imaging unit,
The control means changes the correction target area so that the correction target area determined by the control means becomes a new correction target area based on the distance information measured by the distance measuring means for each area. The imaging device according to any one of Configurations 1 to 7.

(Configuration 9)
comprising distance measuring means for measuring the distance from the imaging device to the subject for each of the plurality of regions in the image captured by the imaging unit,
Imaging according to any one of configurations 1 to 7, wherein the control means changes the amount of correction of the brightness value in the correction target area based on information on the distance measured for each area by the distance measurement means. Device.

(Configuration 10)
10. The imaging device according to any one of configurations 1 to 9, wherein the illumination section irradiates infrared illumination light.

(Configuration 11)
The first mode is a day mode that captures images by capturing visible light.
11. The imaging device according to any one of configurations 1 to 10, wherein the second mode is a night mode in which imaging is performed by taking in infrared light.

(Configuration 12)
The first direction is the vertical direction,
12. The imaging device according to any one of configurations 1 to 11, wherein the second direction is a horizontal direction.

(Configuration 13)
The imaging unit includes an imaging element,
According to any one of configurations 1 to 12, the optical filter is an IR cut filter that is disposed on the front side of the image sensor and transmits visible wavelength light and blocks near-infrared wavelength light. imaging device.

(Configuration 14)
A method for controlling an imaging device, the method comprising:
Illuminating the imaging area with illumination light,
capturing an image with an imaging unit that is rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
switching between a first mode in which an image is taken with an optical filter switchably arranged in the imaging unit inserted and a second mode in which an image is taken with the optical filter retracted;
Obtaining the angle of the first direction or the second direction of the imaging unit when switching to the second mode and illumination light is irradiated to the imaging area;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
A method for controlling an imaging device, comprising correcting a brightness value in a correction target area based on an angle.

(Configuration 15)
A program for causing a computer to execute a control method for an imaging device,
Illuminating the imaging area with illumination light,
capturing an image with an imaging unit that is rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
switching between a first mode in which an image is taken with an optical filter switchably arranged in the imaging unit inserted and a second mode in which an image is taken with the optical filter retracted;
Obtaining the angle of the first direction or the second direction of the imaging unit when switching to the second mode and illumination light is irradiated to the imaging area;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
A program characterized in that a brightness value in a correction target area is corrected based on an angle.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

The present invention provides a system or device with a program that implements one or more functions of each embodiment described above via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. This can also be achieved by processing. In that case, the program and the storage medium storing the program constitute the present invention. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100 Imaging device 101 Imaging section 102 Image signal processing section 103 Communication section 104 System control section 105 Image display section 106 Infrared illumination section 107 Rotation control section 108 Main body section

Claims (15)

an illumination unit that irradiates the imaging area with illumination light;
an imaging unit rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
an optical filter switchably disposed in the imaging section;
a control means for switching between a first mode of imaging with the optical filter inserted and a second mode of imaging with the optical filter retracted; obtaining the angle of the first direction or the second direction of the imaging unit when the illumination unit is irradiating the illumination light onto the imaging area when switching to the mode;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
An imaging device characterized in that a brightness value in the correction target area is corrected based on the angle. The imaging device according to claim 1, wherein the control unit determines a part of an area in an image captured by the imaging unit as the correction target area in conjunction with a timing at which the angle is acquired. The imaging device according to claim 1, wherein the control means gradually changes the amount of correction of the luminance value in the correction target area from the correction target area to an area different from the correction target area. The imaging device according to claim 1, wherein the control means changes the correction target area based on the irradiation intensity of the illumination light. The imaging device according to claim 1, wherein the control means changes the amount of correction of the brightness value in the correction target area based on the irradiation intensity of the illumination light. The imaging unit has a zoom lens,
The control means changes the correction target area based on the zoom magnification of the zoom lens so that the correction target area determined by the control means becomes a new correction target area. 1. The imaging device according to 1. The imaging unit has a zoom lens,
The imaging device according to claim 1, wherein the control means changes the amount of correction of the brightness value in the correction target area based on the zoom magnification of the zoom lens. comprising distance measuring means for measuring the distance from the imaging device to the subject for each of a plurality of regions in the image captured by the imaging unit,
The control means changes the correction target area so that the correction target area determined by the control means becomes a new correction target area based on the distance information measured by the distance measuring means for each area. The imaging device according to claim 1, wherein the imaging device changes. comprising distance measuring means for measuring the distance from the imaging device to the subject for each of a plurality of regions in the image captured by the imaging unit,
The imaging device according to claim 1, wherein the control means changes the amount of correction of the brightness value in the correction target area based on information on the distance measured by the distance measurement means for each area. . The imaging device according to claim 1, wherein the illumination unit emits infrared illumination light. The first mode is a day mode in which imaging is performed by capturing visible light,
The imaging device according to claim 1, wherein the second mode is a night mode in which imaging is performed by capturing infrared light. the first direction is a vertical direction,
The imaging device according to claim 1, wherein the second direction is a horizontal direction. The imaging unit includes an imaging element,
2. The imaging device according to claim 1, wherein the optical filter is an IR cut filter that is disposed on the front side of the imaging device and transmits visible wavelength light and blocks near-infrared wavelength light. A method for controlling an imaging device, the method comprising:
Illuminating the imaging area with illumination light,
capturing an image by an imaging unit rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
Switching between a first mode in which an image is captured in a state in which an optical filter switchably arranged in the imaging unit is inserted, and a second mode in which an image is captured in a state in which the optical filter is retracted;
obtaining the angle of the first direction or the second direction of the imaging unit when switching to the second mode and irradiating the imaging region with the illumination light;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
A method for controlling an imaging device, comprising correcting a brightness value in the correction target area based on the angle. A program for causing a computer to execute a control method for an imaging device,
Illuminating the imaging area with illumination light,
capturing an image by an imaging unit rotatable in at least one of an axis in a first direction and an axis in a second direction perpendicular to the first direction;
Switching between a first mode in which an image is captured in a state in which an optical filter switchably arranged in the imaging unit is inserted, and a second mode in which an image is captured in a state in which the optical filter is retracted;
obtaining the angle of the first direction or the second direction of the imaging unit when switching to the second mode and irradiating the imaging region with the illumination light;
Based on the obtained angle, a part of the area in the image captured by the imaging unit is determined as a correction target area,
A program for correcting a brightness value in the correction target area based on the angle.

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