JP4972423B2 - Camera device and control method thereof - Google Patents

Description

  The present invention relates to a camera device including a plurality of cameras having different distances to a subject to be photographed, and illumination means for illuminating the subject of each camera, and a control method thereof.

  2. Description of the Related Art Conventionally, surveillance cameras for monitoring various purposes such as surveillance in various facilities such as stores and on the ground, streets, railway stations, airports, schools, and crime prevention of private houses are known.

  For example, Patent Document 1 includes a plurality of cameras having different distances to a subject to be photographed, and a plurality of photographing targets existing at different distances are each represented by a plurality of cameras having different distances to the subject according to the distance. There has been proposed a camera device that can capture and monitor all the shooting targets clearly by simultaneously capturing images.

Moreover, such a monitoring camera apparatus is provided with an illuminating device, and can take a picture by illuminating the field of view with the illuminating device at night or in the dark.
JP 2006-14291 A

  However, in the camera device of Patent Document 1 in which a plurality of cameras having different distances to a subject are simultaneously photographed with respect to each photographing object existing at different distances, the field of view is obtained at night or in the dark by the illumination device provided in the camera device. In the case of illuminating the subject, the amount of light that is illuminated becomes smaller as the subject is located at a far distance, so the image obtained by the camera having a longer distance to the subject becomes darker. As a result, the brightness of a plurality of images obtained from a plurality of cameras with different distances to the subject is non-uniform, and there is a problem that the performance as an image for observing the subject to be photographed decreases.

  In view of the above circumstances, the present invention uses a camera device including a plurality of cameras with different distances to a subject to be photographed, and illuminates the field of view with illumination means at night or in the dark, It is an object of the present invention to provide a camera device that can make the brightness of an image obtained by shooting with the same and a control method used therefor.

  The camera device of the present invention includes a plurality of cameras having different distances to a subject to be photographed and illumination means for illuminating the subject of each camera, and illuminates the subject of one camera among the plurality of cameras. In a camera device in which the illumination range overlaps at least part of the field of view of another camera, the shooting timings of the multiple cameras are made different, and the distance to the subject is long depending on the distance to the subject of each camera that shoots It is characterized by comprising control means for controlling the illumination means so as to increase the amount of light that illuminates the subject of the illumination means.

  Here, “different shooting timings of multiple cameras” means that the flash illumination timing is slightly shifted for each subject in order to change the amount of light illuminated for each subject present at different distances by the same illumination means. In terms of the photographer's consciousness or the operation of the surveillance camera, it means that the photograph is taken with the intention of photographing at the same time.

  The control method of the present invention includes a plurality of cameras having different distances to a subject to be photographed and illumination means for illuminating the subject of each camera, and illuminates a subject of one camera among the plurality of cameras. Different shooting timings of a plurality of cameras in a camera device whose range overlaps at least part of the field of view of another camera, and the longer the distance to the subject according to the distance to the subject of each camera to be photographed, The illumination means is controlled to increase the amount of light that illuminates the subject.

  In the apparatus and method of the present invention, each camera may shoot a moving image. When shooting a moving image, control is performed so that the amount of illumination light is changed in accordance with the shooting of the frames whose shooting timing is shifted for each camera.

  Each camera may be provided with a photographing lens having a shorter focal length as the distance to the subject of the camera is shorter.

  According to the camera device and the control method thereof of the present invention, the camera apparatus includes a plurality of cameras having different distances to the subject to be photographed, and illumination means for illuminating the subject of each camera, and one of the plurality of cameras is provided. Illumination means for illuminating a subject in the field of view of a camera device in which the illumination range for illuminating the subject of the camera overlaps at least a part of the field of view of another camera at the time of photographing with the plurality of cameras having different distances to the subject The amount of light that illuminates the subject is controlled to increase as the distance to the subject increases according to the distance to the subject of each camera that shoots, so the brightness of the image obtained by each camera Can be made uniform.

  Hereinafter, an embodiment of a camera device according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a camera device according to an embodiment of the present invention, and FIG. 2 is a time chart showing operations of a photographing unit and an illuminating unit at the time of still image photographing by the camera device of FIG.

A camera apparatus 1 shown in FIG. 1 includes an imaging unit 10 that includes two cameras C ₁ and C ₂ having different subject distances, an illumination unit 20 that illuminates the subjects of the cameras C ₁ and C ₂ , Control for controlling the illuminating means 20 so as to increase the amount of light that illuminates the subject of the illuminating means 20 as the subject distance increases in accordance with the subject distance of each camera that shoots, while varying the photographing timing of the cameras C ₁ and C _2. Means 30 are provided.

  Here, the subject distance means the distance to the subject in focus set for each camera.

Imaging means 10, the camera _{C 1} and the object distance object distance is _{d 1} is equipped with a camera _{C 2 (d 1 <d 2} ) is _{d 2,} each of the cameras _C 1, _{C 2} has a partially overlapping The visual fields S ₁ and S ₂ to be photographed are respectively photographed. The focal lengths of the cameras C ₁ and C ₂ are f ₁ and f ₂ (f ₁ ≦ f ₂ ), respectively. In addition, the cameras C ₁ and C ₂ perform shooting timing shooting set by a clock signal or the like generated by the control unit 30, for example.

Each of the cameras C ₁ and C ₂ includes an optical system including a photographic lens having a predetermined focal length f ₁ or f _{2 with} which a required subject distance d ₁ or d ₂ can be obtained, and behind the optical system, It has a photographing element such as a CCD, an A / D converter, etc., and an analog image signal obtained by photoelectrically converting the subject light that has passed through the optical system by a photographing element such as a CCD is obtained by an A / D converter. The digital image signal is converted and output.

Illuminating means 20 is for illuminating an object for each camera C _1, C _2, the illumination range for illuminating the object of the camera C ₁ are overlapped with part of the field of view of the camera C _2, the subject of the camera C ₂ illumination range of the illumination overlaps with a portion of the field of view of the camera C _1. The illumination means 20 can be controlled so as to illuminate a subject in the field of view of the camera with a desired light amount at the time of each photographing in accordance with the photographing timing of each camera of the photographing means 10. Specifically, the shooting T ₁ by the camera C _1, and illuminates an object in the field of view at a light quantity L ₁ which is suitable for photographing by camera C ₁ to fit the shooting timing, the shooting T ₂ by the camera C ₂ Can be controlled to illuminate the subject in the field of view with a light amount L ₂ suitable for photographing by the camera C ₂ in accordance with the photographing timing. Here, the light amounts L ₁ and L ₂ irradiated at the time of photographing by each camera are controlled by the control means 30 described later.

  As a light source that can be controlled in this way, for example, a light emitting diode (hereinafter referred to as an LED), a desired light amount obtained by controlling the magnitude of the current supplied to the LED, and the shooting timing of each camera. What is irradiated together can be used. Not limited to this, for example, a plurality of LEDs that can be lit with a predetermined amount of light are provided, and the desired amount of light obtained by adjusting the number of LEDs to be blinked at the same time is irradiated in accordance with the shooting timing of each camera. It is also possible to use a plurality of LEDs with different amounts of light to be emitted, and to match the shooting timing of each camera with a desired light amount obtained by selecting the corresponding LED according to the desired light amount. May be used, or may be irradiated in accordance with the shooting timing of each camera with a desired amount of light obtained by adjusting the irradiation time of an LED that is lit at a predetermined brightness per unit time May be used.

  The light source is not limited to the light source exemplified above, and any light source may be used as long as it can irradiate with a desired light amount in accordance with the photographing timing of each camera. In addition, the light emitted from the light source may be infrared light or visible light.

The control means 30 controls the imaging timing of the cameras C ₁ and C ₂ and the illumination timing of the illumination means 20 by a clock signal generated by a clock generation means (not shown), as well as each camera C ₁ and C _{2 to be} imaged. The light quantity of the illumination means 20 that illuminates the subject in the field of view is controlled according to the subject distances d ₁ and d ₂ .

Specifically, the shooting timings of the cameras C ₁ and C ₂ are slightly shifted (about 1/60 seconds in this embodiment) so that shooting is performed in order, and shooting by the cameras C ₁ and C ₂ is performed. The subject within the field of view of the camera device is illuminated by the illumination means 20 in accordance with the timing. Here, the light quantity at the time of photographing the object distance is due to a small camera C _1, to set the amount of light illuminating the object of the camera C ₁ small, at the time of photographing the object distance is due to long camera C _2, illuminating the object of the camera C ₂ Is controlled so that the brightness of the image obtained by each camera is uniform.

Thereby, for example, as shown in time charts (a) to (c) illustrating the operations of the photographing unit and the illuminating unit at the time of still image photographing illustrated in FIG. 2, the operation mode of the camera C ₁ is in the on state at time dt ₁ . Then, the photographing is performed, the operation mode of the illumination unit 20 is turned on, and illumination is performed with the light amount L ₁ set according to the subject distance of the camera C ₁ . Once captured by the camera C ₁ is complete, then imaging is performed by the camera C _2. Together with the operation mode of the camera C ₂ shooting is performed in an ON state at time dt _2, illuminating means operation mode 20 is turned on, the light amount is set according to the object distance of the camera C ₂ L ₂ Illumination is performed at (L ₁ <L ₂ ).

Further, at the time of shooting a moving image by the camera apparatus 1, for example, a moving image of 30 frames / second is shot by each camera by repeatedly performing the same processing as that at the time of shooting a still image at a high speed. Then, for example, as in the time chart showing the operation of the imaging means and the illumination means at the time of moving image shooting as shown in FIG. 3 (a) ~ (c) , slightly photographing timing of the camera C ₁ and the camera C ₂ (the (In the embodiment, about 1/60 second) The shooting by each camera C ₁ , C ₂ is alternately repeated, and the time dt ₁₁ when the operation mode of the camera C ₁ is on and shooting is performed. In dt ₁₂ ,..., time dt _{21 when the} illumination unit 20 illuminates with the light amount L ₁ set according to the subject distance of the camera C ₁ and the camera C ₂ is turned on to perform shooting. , Dt ₂₂ ,... Are illuminated by the illumination means 20 with a light amount L ₂ (L ₁ <L ₂ ) set according to the subject distance of the camera C ₁ .

When shooting a moving image in this way, the luminance distribution detection for detecting the luminance distribution of the subject from each of the plurality of images P ₁ and P ₂ photographed by the cameras C ₁ and C ₂ of the photographing unit 10 in the control unit 30. comprising means, based on the luminance distribution of the subject in the image P ₁ obtained by the luminance distribution detecting means, the magnitude of the amount of light irradiated from the illuminating means 20 at the time of photographing to be performed next is corrected by the camera C _1, based on the luminance distribution of the subject in the image P ₂ obtained by the luminance distribution detecting unit, by the camera C ₂ can be corrected size of the amount of light irradiated from the illuminating means 20 at the time of photographing to be performed next.

Specifically, from a plurality of images P _i (i = 1, 2) photographed by the camera C _i (i = 1, 2), for example, as described in Japanese Patent Application Laid-Open No. 2003-337362 and the like. The brightness distribution of the shooting target (main subject) to be monitored is detected using a sensor array that detects the brightness distribution of the subject, and the brightness of the shooting target calculated from the detected brightness distribution is preset. is lower than the lower limit of the allowable range, at the time of the next shooting by the camera C _i, so that the light amount of the illumination means for illuminating the object within its field of view is greater than the value set by the object distance of the camera C _i In addition, the correction value is set as a value larger than a predetermined reference value K. Conversely, if higher than the upper limit of the allowable range brightness of the imaging target is preset, at the time of the next shooting by the camera C _i, the amount of illumination means for illuminating the object within the field of view thereof setting the correction value to be less than the value set by the object distance of the camera C _i as a predetermined reference value K smaller value.

  Hereinafter, with reference to FIG. 4, a process for correcting the light amount of the illumination unit 20 using the correction value set based on the brightness of the photographing target obtained by the luminance distribution detection unit will be described.

Shooting brightness of the subject H ₁ of the camera C ₁ by the first shooting to the image obtained under illumination of the light amount L ₁₁ of the set illumination device according to the object distance of the camera C ₁ is a predetermined tolerance If less than the lower limit value, as shown in FIG. 4, the correction value of the light amount at the time of the second shooting by the camera C ₁ is set as a predetermined reference value K greater than K _+1, lighting device at the time of the second shooting 20 amount L ₁₂ emitted by the is set to be larger than the amount of light L ₁₁ at the first shooting.

Further, in the second shooting, when shooting the brightness of the subject H ₁ in an image obtained by photographing by the camera C ₁ are still less than the lower limit of the predetermined allowable range, the amount of the correction value at the third-shooting Is set as a value K _{+2 that} is larger than the correction value for the second time, and the light amount L ₁₃ irradiated by the lighting device 20 at the time of the third shooting is set to be larger than the light amount L ₁₂ at the time of the second shooting. The

Thereafter, in the third time, the fourth time,..., When the brightness of the subject H ₁ in the image obtained by the camera C ₁ is smaller than the lower limit value of the predetermined allowable range, the correction value is increased, When the value is larger than the upper limit value, the correction value is decreased to correct the amount of light irradiated by the illumination device 20 so that the brightness of the subject H ₁ in the image obtained by the camera C ₁ falls within a predetermined allowable range. Done. In the case shown in FIG. 4, the brightness of the subject H ₁ in the image obtained by the camera C ₁ after the third time is within a predetermined allowable range, and the correction value K ₊₂ set for the third time photography. and the light quantity L ₁₃ of the illumination means is applied to the imaging by the camera C ₁ for the third time after.

Similar to the time of photographing by the camera C _1, even when the photographing by the camera C _2, when each of the shooting, a smaller lower limit of the brightness is a predetermined tolerance of the photographic subject H ₂ in the resulting image by the camera C ₂ In such a case, the correction value is increased, and if the correction value is larger than the upper limit value, the correction value is decreased, so that the brightness of the subject H ₂ in the image obtained by the camera C ₂ falls within a predetermined allowable range. The amount of light irradiated by 20 is corrected.

Further, FIG. 4 shows a case where the brightness of the photographing target H ₂ in the images obtained by the first and second cameras C ₂ is larger than the upper limit value of the predetermined allowable range. The case where the correction value of the light amount at the time of photographing is set to be small and the light amount L irradiated by the illumination device 20 is corrected accordingly is illustrated.

  According to the above-described embodiment, the illumination unit is controlled so that the amount of light that illuminates the subject of the illumination unit increases as the distance to the subject increases according to the distance to the subject of each camera. The brightness of an image obtained by photographing can be made uniform.

  Further, by controlling the amount of light of the illumination unit 20 based on the subject distance in each camera and the brightness of the shooting target in the image obtained by the camera, the shooting target was shot with brightness within a predetermined allowable range. An image can be acquired, and the efficiency of monitoring using the acquired image can be further improved.

In the above embodiment, the case where the photographing unit is configured by two cameras having different distances to the subject has been described. However, as shown in FIG. 5, two camera groups G1 having different distances to the subject, G2 may be provided, and each camera group may have one or more cameras, and the entire field of view of each camera group may be divided and photographed by the one or more cameras. In the camera device 2 of FIG. 5, the camera unit G1 has two cameras _{C 11, C 15} subject distance is _{d 1,} the camera unit G2 three subject distance _{d 2} of the camera _{C 12, C 13,} It has a C _14.

In the above embodiment, setting the photographing timing in the camera C _1, C ₂ forward, the case has been described where the irradiation is performed by the illumination device in accordance with the timing thereof, the lighting device is illuminated during photographing by the camera in order quantity is small or large criteria such in order may be set photographing timing by the camera C _1, C ₂ are used.

For example, when shooting using five cameras C ₁₁ -C _15, as shown in FIG. 5, the camera C _11, ..., is not limited to the method of setting the order of shooting time of C _15, more subject distance is long Since the amount of light emitted by the illumination unit is large, when photographing is performed in ascending order of the amount of light, photographing is performed in order of the subject distance, for example, in order of cameras C ₁₁ , C ₁₅ , C ₁₂ , C ₁₃ , C _14. It is also possible to set the timing.

  Moreover, although the case where illumination by an illuminating device is intermittently performed in synchronization with the photographing timing by each camera has been described, for example, illumination by the illuminating device is continuously performed, and a desired light amount is obtained at the photographing timing by each camera. The amount of illumination light may be continuously increased or decreased so as to be illuminated.

1 is a schematic configuration diagram of a camera device according to an embodiment of the present invention. Time chart showing operation of photographing means and illumination means at the time of still image photographing Time chart showing operation of photographing means and illumination means at the time of moving image photographing The figure for demonstrating correction | amendment of the light quantity of an illumination means The schematic block diagram which shows the camera apparatus which is other embodiment by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Camera apparatus 10 Image | photography means 20 Illumination means 30 Control means C Camera d Subject distance L Light quantity S Field of view

Claims (2)

A plurality of cameras having different focal lengths, and a single lighting means having within the illumination range field of view of the plurality of cameras, each said camera met each camera device performs continuous shooting at a predetermined interval And
Control means for controlling the illuminating means so as to increase the amount of light that illuminates the illumination range as the focal length of the camera becomes longer at the time of photographing by each camera , while different photographing timings of the plurality of cameras are provided. A camera device characterized by the above. In a camera device comprising a plurality of cameras having different focal lengths and one illumination means having a visual field range of the plurality of cameras within the illumination range, and continuously shooting at a predetermined interval for each camera , The control is characterized in that the shooting timings of the plurality of cameras are made different , and the lighting means is controlled so that the amount of light that illuminates the illumination range increases as the focal length of the cameras increases when shooting by each camera. Method.

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