JP4341102B2 - Imaging apparatus and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus having an imaging element capable of imaging in the visible light region and the infrared light region, and a control method thereof .
[0002]
[Prior art]
Currently, a moving image and / or a still image can be taken using a camera-integrated digital VTR or a digital still camera (hereinafter collectively referred to as a digital camera). Recently, digital cameras capable of taking infrared images have also appeared.
[0003]
When photographing a dark place with this digital camera capable of infrared imaging, it is necessary to remove the infrared light cut filter from the optical path and shoot the infrared auxiliary light against the subject. That is, the infrared light region can be imaged by removing the infrared light cut filter of the optical system of the digital camera from the optical path. And this infrared photography which can photograph brightly in a dark place is used for observation of nocturnal animals and photographing infants' sleeping faces.
[0004]
[Problems to be solved by the invention]
However, when the infrared light cut filter is removed from the optical system of the digital camera and photographing is performed in a place where there is much infrared light such as outdoors in the daytime, there is a problem that an inappropriate image is formed.
[0005]
Accordingly, an object of the present invention is to shoot an appropriate image when shooting with the infrared light cut filter removed from the optical system of the digital camera, or when shooting with a digital camera having no infrared light cut filter. An imaging device that can be used and a control method thereof .
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided an imaging apparatus having an imaging device capable of imaging in the visible light region and the infrared light region, and a changing unit capable of manually changing transmission or shielding of infrared light, and an imaging device. An erroneous operation is determined based on signal processing means for processing the obtained image signal, detection means for detecting brightness when the image signal is photographed, transmission of infrared light, and detection result of the detection means. And an output device that outputs an error message. It is.
The invention according to claim 8 is a method for controlling an imaging apparatus having an imaging device capable of imaging in the visible light region and the infrared light region, and the transmission or shielding of infrared light can be changed manually. A change step, a signal processing step for signal processing of the image signal obtained from the image sensor, a detection step for detecting brightness when the image signal is photographed, transmission of infrared light, and detection results of the detection step And an output step for outputting a message indicating an erroneous operation.
[0007]
When shooting in a place with a lot of infrared light, such as outdoors in the daytime, when the infrared light cut filter is out of the optical path and the camera is mistakenly operated, smearing processing (mosaic processing) is performed on the captured image signal. By giving it, the photographer is informed of the erroneous operation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration of an embodiment to which the present invention is applied. An infrared light cut filter 1 (hereinafter referred to as an IR cut filter) is put in and out by a switch 2 connected thereto. The switch 3 is turned on / off in conjunction with the switch 2. The on / off of the switch 3 supplies the controller 10 with the IR cut filter 7 as switch on / off information.
[0009]
If the IR cut filter 1 is removed from the optical system, color reproduction cannot be performed accurately, so that the output image does not become a normal color. Therefore, in this embodiment, the IR cut filter 1 can be taken in and out of the optical path so that normal photographing not intended for photographing in the infrared light region can be performed.
[0010]
In this embodiment, incident light is irradiated to the CCD image pickup device 7 through the zoom lens 4, the IR cut filter 1, the iris 5 for adjusting the brightness, and the focus lens 6. As the CCD image pickup device 7, a device capable of photographing in the visible light region and the infrared light region is used. In the CCD image sensor 7, the incident light that has been irradiated is converted into an electrical signal, and is supplied to the gain control and A / D converter 8. In the gain control and A / D converter 8, the image signal from the CCD image pickup device 7 is amplified and digitized. Thus, the image signal gain-controlled and digitized by the A / D converter 8 is supplied to the camera signal processing circuit 9.
[0011]
The camera signal processing circuit 9 performs signal processing, for example, primary color separation method and contour correction, on the supplied image signal. In this primary color separation method, a luminance signal and a color difference signal are generated from the supplied signal, and R, G, B signals of the primary colors are separated from the generated luminance signal and color difference signal, and the separated R, G, B signals are separated. From this, a luminance signal and a color difference signal are generated again. In the contour correction, the contour of the subject is emphasized. Furthermore, in this embodiment, the brightness of the supplied image signal is detected, and the result is communicated with the controller 10.
[0012]
One of the LEDs 11 is grounded, and the other is connected to the positive side of the battery 13 via the switch 12. The negative side of the battery 13 is grounded. The switch 12 is turned on / off by the controller 10, and the LED 11 emits infrared light in accordance with the on / off. When the LED 11 emits light, the infrared light region can be photographed in a dark place.
[0013]
The controller 10 is composed of a microcomputer as an example. The controller 10 detects whether or not the IR cut filter 1 is used from the switch on / off information. The controller 10 is supplied with the brightness of incident light from the camera signal processing circuit 9 and controls the iris 5 by the iris control signal. Further, the controller 10 controls gain control and the A / D converter 8 by a gain control signal. The controller 10 communicates with the camera signal processing circuit 9 and controls the camera signal processing circuit 9. Furthermore, the controller 10 controls the LED 11 that emits infrared light.
[0014]
As will be described later, the mosaic processing circuit 14 performs mosaic processing on the image signal supplied from the camera signal processing circuit 9 when it is determined that the IR cut filter 1 is off the optical path as an erroneous operation. Is done. In the mosaic process, the controller 10 controls the on / off of the mosaic. The image signal that has been subjected to the mosaic processing is output from the output terminal 15 to an electronic viewfinder and recording means (not shown). An image subjected to mosaic processing is displayed on the electronic viewfinder. As recording means, there are a magnetic tape, a semiconductor, a magnetic disk, a magneto-optical disk, and the like, and a moving image and / or a still image are recorded on these.
[0015]
Thus, when the switch 2 is on the off side, the light passes through the IR cut filter 1. However, when the switch 2 is on, the IR cut filter 1 is not on the optical path, so that the light does not pass through the IR cut filter 1 but is focused by the iris 5 and passes through the focus lens 6, and the CCD image sensor. The light is received at 7 and converted into an electrical signal. At this time, since the CCD image pickup device 7 has sensitivity in the infrared light region, it can take a bright image with the infrared light of the LED 11 even in a dark place. Amplification is controlled by gain control and gain control of the A / D converter 8, converted into a digital signal, and brightness information and the like are detected by the detection unit of the camera signal processing circuit 9. The detection information is transmitted to the controller 10 by serial communication between the camera signal processing unit 9 and the controller 10.
[0016]
The algorithm of the controller 10 is shown in the flowchart of FIG. In step S1, since the controller 10 performs processing in synchronization with the vertical synchronization signal (VD) generated by the camera signal processing circuit 9, the vertical synchronization signal is confirmed. In step S1, the control in step S1 is repeated until the vertical synchronization signal is confirmed. After the vertical synchronization signal generated by the camera signal processing circuit 9 is confirmed, communication processing between the camera signal processing circuit 9 and the controller 10 is performed in step S2. In step S3, brightness is detected by the camera signal processing circuit 9, and the detected value is transmitted to the controller 10 by communication, and is converted into an evaluation value by the controller 10.
[0017]
In step S4, the brightness evaluation value is compared with a predetermined threshold value, and if it is determined that the brightness evaluation value is greater than the predetermined threshold value, the control returns to step S5 to return the brightness. If it is determined that the evaluation value is smaller than the predetermined threshold value, the control moves to step S1. In step S5, on / off of the switch 3 is determined based on the switch on / off information obtained from the switch 3. When the switch 3 is determined to be on, control is transferred to step S6, and the switch 3 is turned off. If determined, control returns to step S1. In step S6, the mosaic processing circuit 14 performs mosaic processing on the supplied image signal.
[0018]
When the switch 2 is on, that is, when the IR cut filter 1 is not on the optical path, the detection result from the camera signal processing circuit 9 is referred to. When the evaluation value obtained from the detection result is larger than a predetermined threshold value, that is, when the evaluation value is bright, communication data for performing mosaic processing in the camera signal processing circuit 9 is set.
[0019]
The mosaic setting data is serially communicated to the mosaic processing circuit 14 by the next vertical synchronization signal, and the mosaic processing is performed on the image signal. Therefore, the image signal of the photographed subject becomes a mosaic image and a correct image cannot be confirmed. With the above operation, it is possible to notify the photographer of an erroneous operation that the IR cut filter 1 is off the optical path.
[0020]
In this embodiment, as a method of notifying the photographer that the IR cut filter 1 is off the optical path, the image is subjected to mosaic processing. Instead of performing this mosaic processing, the digital camera is turned on. It may be cut off to notify the photographer of an erroneous operation, or a superimpose or the like may be displayed in the captured image to notify the photographer of the erroneous operation.
[0021]
Another example for detecting an erroneous operation is shown in FIG. The sensor section shown in FIG. 3 is attached around the lens of the digital camera. Two photosensors 22 and 23 are attached to a transparent light guide 21 made of a material such as transparent plastic or glass. The transparent light guide 21 is divided into two branches on the light emission side. A visible light photosensor 22 having a light receiving sensitivity in the visible light region is attached to one of the forks, and an infrared light photosensor having a light receiving sensitivity in the infrared light region is attached to the other. 23 is attached. Thereby, the incident light is equally input to the photosensors 22 and 23.
[0022]
The advantage of providing the visible light photosensor 22 and the infrared light photosensor 23 is that an erroneous operation can be determined more accurately. Specifically, when an image is taken with a neutral density filter such as a visible light cut filter or an ND filter attached to the front surface of the lens, an erroneous operation may be erroneously determined only by information on the light emitted to the CCD image sensor 7. However, by providing an independent sensor, it is possible to accurately obtain a condition for determining an erroneous operation without being affected by the filter on the front surface of the lens.
[0023]
In addition, since the transparent light guide 21 is used, it is difficult to mask only one of the photosensors 22 or 23 when a finger or the like is unexpectedly placed on the front surface of the sensor. There is also.
[0024]
In FIG. 4, an example of the characteristic of LED11 and the photosensors 22 and 23 is shown. 4A shows sensitivity characteristics of the photosensor 22 for visible light, FIG. 4B shows output characteristics of the LED 11 that emits infrared light, and FIG. 4C shows sensitivity characteristics of the photosensor 23 for infrared light. In this embodiment, the output characteristic of the LED 11 shown in FIG. 4B is close to the sensitivity characteristic of the photosensor 23 for infrared light so that it can be easily determined that the image is captured as auxiliary light for infrared imaging. It has been.
[0025]
FIG. 5 shows an example of combinations of outputs from the photosensors 22 and 23 when the switch 2 is turned on, that is, when the IR cut filter 1 is removed from the optical path.
[0026]
When the output of the photosensor 22 is at the H (high) level and the output of the photosensor 23 is at the H level, it is determined that the environment is in the presence of both visible light and infrared light, that is, outdoors in the daytime. In this case, the reason why the IR cut filter 1 is off the optical path is that the photographing environment is an erroneous operation, so the photographer is warned by the method described above.
[0027]
Next, when the output of the photo sensor 22 is L (low) level and the output of the photo sensor 23 is H level, the LED 11 emits infrared light in an environment where there is little visible light and much infrared light. It is determined that the image is taken in the infrared light region in the dark using. In this case, even if the IR cut filter 1 is out of the optical path, no warning is made because no erroneous operation occurs.
[0028]
When the output of the photosensor 22 is at the H level and the output of the photosensor 23 is at the L level, an environment where there is a large amount of visible light and a small amount of infrared light, that is, an infrared component such as a fluorescent lamp. It is judged that the room is under low lighting. In this case, even if the IR cut filter 1 is off the optical path, since the photographer intends to capture an image, no erroneous operation is performed, so no warning is given.
[0029]
Further, when the output of the photosensor 22 is L level and the output of the photosensor 23 is L level, in an environment where both visible light and infrared light are low, that is, darkness where no infrared light exists, or transparent light guide It is determined that the light receiving portion of the vessel 21 is unexpectedly masked with a finger or the like. In this case, the brightness detection result by the light obtained from the CCD image pickup device 7 and the on / off information of the LED 11 are also used in combination, and it is determined whether or not the operation is erroneous.
[0030]
When both the outputs of the photosensors 22 and 23 are at the L level, if the detection result of the brightness of the output of the CCD image sensor 7 is small and the LED 11 is turned off, it is determined to be dark, and the IR cut filter 1 is on the optical path. Even if it is out of the range, it will not be erroneously operated, so no warning is given. However, when the outputs of the photosensors 22 and 23 are both at the L level, the IR detection filter 1 is light when the detection result of the brightness of the output of the CCD image sensor 7 is small and the LED 11 is turned off. Since the shooting environment that is out of the way is an erroneous operation, the photographer is warned by the method described above.
[0031]
At this time, the output value of the CCD image sensor 7 is referred to as a countermeasure when the sensor unit is unexpectedly masked with a finger or the like. The on / off information of the LED 11 is referred to as a countermeasure when the sensor unit is masked with a finger or the like and a neutral density filter is attached to the front surface of the lens.
[0032]
In this embodiment, the IR cut filter can be taken in and out from the optical system of the digital camera, but a digital camera having no IR cut filter may be used. In this case, when shooting outdoors in the daytime when there is a lot of infrared light, it is determined as an erroneous operation, and the captured image is subjected to processing such as mosaic.
[0033]
In this embodiment, the mosaic process is performed on the image as an example of the blurring process, but any process may be performed as long as it is a process that blurs the image.
[0034]
【The invention's effect】
According to the present invention, in a digital camera having a CCD imaging device capable of photographing in the infrared light region, it is possible to prevent an erroneous operation of photographing by removing the infrared light cut filter from the optical path in a bright place. Further, even when a neutral density filter such as an ND filter or a visible light cut filter is attached to the front surface of the lens, it is possible to detect an erroneous operation of taking an image by removing the infrared light cut filter from the optical path.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment to which the present invention is applied.
FIG. 2 is a flowchart for explaining a controller algorithm to which the present invention is applied;
FIG. 3 is a block diagram of another embodiment to which the present invention is applied.
FIG. 4 is an example of characteristics of an LED and a photosensor applied to the present invention.
FIG. 5 is for explaining the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Infrared light cut filter, 2, 3, 12 ... Switch, 4 ... Zoom lens, 5 ... Iris, 6 ... Focus lens, 7 ... CCD image sensor, 8 ..Gain control, A / D converter, 9 ... Camera signal processing circuit, 10 ... Controller, 11 ... LED, 13 ... Battery, 14 ... Mosaic processing circuit

Claims (8)

In an imaging device having an imaging element capable of imaging in the visible light region and the infrared light region,
Change means capable of changing transmission or shielding of infrared light manually;
Signal processing means for performing signal processing on an image signal obtained from the imaging element;
Detecting means for detecting brightness when the image signal is captured;
An imaging apparatus comprising: an output unit that determines an erroneous operation based on the transmission of the infrared light and a detection result of the detection unit, and outputs information indicating the erroneous operation.   The imaging apparatus according to claim 1, further comprising an infrared light emitting element that can be turned on / off. The detecting means is
The imaging apparatus according to claim 1, further comprising detection means for detecting the brightness of the imaged image signal. The detecting means is
A first photosensor having light receiving sensitivity only in the visible light region;
The imaging apparatus according to claim 1, comprising: a second photosensor having a light receiving sensitivity only in an infrared light region. The output means is
The imaging apparatus according to claim 1, wherein when it is determined that the operation is incorrect, the image is subjected to a blurring process. The output means is
The imaging apparatus according to claim 1, wherein the power supply is shut off when it is determined that the operation error has occurred. The output means is
The imaging apparatus according to claim 1, wherein when the erroneous operation is determined, the image is superimposed. A method for controlling an imaging apparatus having an imaging element capable of imaging a visible light region and an infrared light region,
A change step capable of manually changing the transmission or shielding of infrared light; and
A signal processing step of performing signal processing on an image signal obtained from the imaging element;
A detection step for detecting brightness when the image signal is captured;
An imaging apparatus control method comprising: an output step of determining an erroneous operation based on the transmission of the infrared light and the detection result of the detection step, and outputting that the erroneous operation.

Images