JP2016201722A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output an image having high color reproducibility and a large signal-to-noise ratio even in the case where the quantity of visible light of a subject is lacked, in an imaging apparatus.SOLUTION: The imaging apparatus comprises: an imaging part 101 which has sensitivity with respect to visible light and invisible light and outputs an optical image that is photo-detected with a preset imaging parameter, as an electric signal; a visible light signal generation part 104 which extracts a visible light signal from the electric signal; an invisible light signal generation part 105 which extracts an invisible light signal from the electric signal; a signal detection part 114 which outputs lightness information from the electric signal; a visible light detection part 112 which detects the visible light signal and outputs visible light luminance information; an invisible light detection part 113 which detects the invisible light signal and outputs invisible light luminance information; a light source 116 capable of controlling the quantity of invisible light to be radiated; and a control part 110 which sets the imaging parameter to the imaging part based on the lightness information. The control part 110 controls the imaging parameter and the quantity of light to be radiated from the light source based on the visible light luminance information and the invisible light luminance information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging method and an imaging apparatus.

  As a background art in this technical field, there is JP 2010-212941 (Patent Document 1). In this publication, “[Problem] Regarding an imaging device and a TV door phone device, even when a color photographed image is obtained so that the light illuminated for the subject does not become dazzling in a dark place, the subject is visually recognized immediately after the start of photographing. [Solution Means] An imaging device includes an imaging infrared light source unit that illuminates a subject, a visible light source unit that illuminates the subject, and an imaging that shoots the subject. And a light emission control unit that controls light emission of the infrared light source unit for photographing and the visible light source unit for photographing, and the light emission control unit starts emission of infrared light when the imaging unit starts photographing, After the start of light emission, the amount of visible light is increased more gradually than infrared light as time passes. "

JP 2010-212941 A

  In Patent Document 1, an infrared light source is considered as a short-time auxiliary light source for obtaining a sufficient amount of light from a visible light source, and the color of an image obtained from an imaging device when only an invisible light source is used. Reproduction is not considered, and an image with less noise can be obtained by irradiating the subject with strong invisible light, but it has not been taken into account that the subject color cannot be expressed.

  In order to solve the above-described conventional technical problems, the configurations described in the claims are adopted. Although the present application discloses a plurality of means for solving the above-described problems, for example, imaging that has sensitivity to visible light and invisible light and outputs an optical image received with a set imaging parameter as an electrical signal. A visible light signal generation unit that extracts a visible light signal from the electrical signal, a non-visible light signal generation unit that extracts a non-visible light signal from the electrical signal, and a signal detection unit that outputs brightness information from the electrical signal, A visible light detector that detects visible light signals and outputs visible light luminance information, a non-visible light detector that detects non-visible light signals and outputs non-visible light luminance information, and the amount of invisible light to be irradiated A controllable light source, and a control unit that sets an imaging parameter in the imaging unit based on brightness information. The control unit is configured based on the visible light luminance information and the non-visible light luminance information. Imaging to control the amount of light to irradiate It can be solved by location.

  According to the present invention, even when the amount of visible light of a subject is insufficient, an amount of invisible light that is appropriate for the imaging device to capture an image can be emitted from the light source, and the imaging device has good color reproducibility. In addition, there is an effect that an image having a large signal-to-noise ratio can be output.

FIG. 1 is an example of an overall configuration diagram showing an embodiment of the present invention. These are the block diagrams of the image pick-up part of one Example of this invention. These are pixel arrangement examples of one embodiment of the present invention. These are examples of the spectral characteristics of the pixel of one embodiment of the present invention. These are examples of controlling the amount of light emitted from the light source unit of one embodiment of the present invention. These are the example of a processing flow of one Example of this invention. FIG. 1 is an example of an overall configuration diagram showing an embodiment of the present invention. These are examples of controlling the amount of light emitted from the light source unit of one embodiment of the present invention. These are the example of a processing flow of one Example of this invention. Is an example of an acquired image in the present invention. FIG. 1 is an example of an overall configuration diagram showing an embodiment of the present invention. These are examples of controlling the amount of light emitted from the light source unit of one embodiment of the present invention. These are examples of controlling the amount of light emitted from the light source unit of one embodiment of the present invention. FIG. 1 is an example of an overall configuration diagram showing an embodiment of the present invention. These are examples of controlling the amount of light emitted from the light source unit of one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is used for the same element and the overlapping description is abbreviate | omitted.

  In the present embodiment, an imaging device that adjusts the light amount of the invisible light source from the absolute amount of the visible light component of the photographed image and the ratio of the invisible light to the visible light will be described using an example.

  FIG. 1 is an example of a block diagram illustrating the overall configuration of the imaging apparatus according to the first embodiment. 101 is an imaging unit, 103 is a signal processing unit, 104 is a visible light signal generation unit, 105 is a non-visible light signal generation unit, 106 is a white adjustment unit, 107 is an image synthesis unit, 108 is a luminance signal generation unit, 109 is a color difference A signal generation unit, 110 is a control unit, 111 is a white balance detection unit, 112 is a visible light amount detection unit, 113 is an invisible light amount detection unit, 114 is a signal level detection unit, and 116 is a light source unit. Hereinafter, each block will be described.

  The invisible light will be described by taking infrared light as an example, but the present invention is configured so that the color filter of the image sensor section has sensitivity to visible light and ultraviolet light instead of visible light and infrared light. It is also possible to do. If there is sensitivity to infrared light, adding an appropriate infrared light to visible light has the advantage that an image with low noise and good color reproducibility can be obtained even in dark scenes. On the other hand, when it has sensitivity, there is an advantage that a colored ultraviolet light image can be obtained by combining an image only in the ultraviolet light region with a color image of visible light.

  The imaging unit 101 includes, for example, a lens group including an imaging lens, a zoom lens, and a focus lens, an aperture, a shutter, an image sensor such as a CCD or a CMOS, an amplifier, an AD converter, and the like. A plurality of pixel signals corresponding to a predetermined wavelength component are output by spectrally photoelectrically converting the invisible light with various color filters using an image sensor. The predetermined wavelength component is, for example, red light + infrared light, green light + infrared light, blue light + infrared light, and visible light + infrared light including blue to red light.

  The signal processing unit 103 performs, for example, separation processing and demosaic processing for generating a pixel signal for each predetermined wavelength component from the pixel signal output from the imaging unit 101, and outputs a pixel signal for each predetermined wavelength.

  The visible light signal generation unit 104 performs, for example, matrix calculation processing on the pixel signal for each predetermined wavelength component output from the signal processing unit 103, thereby generating each visible light from the pixel signal of each predetermined wavelength component. A visible light signal that is a signal for the component is extracted and output. The visible light signal is, for example, a red signal, a green signal, a blue signal, and a blue signal corresponding to all visible light including red light, green light, blue light, and blue to red obtained by subtracting an infrared light component from a predetermined wavelength component. It is a white signal which is visible light including from red to red.

  The invisible light signal generation unit 105 performs, for example, matrix calculation processing on the pixel signal for each predetermined wavelength component output from the signal processing unit 103, and thereby the invisible light signal is a signal for the invisible light component. Is extracted and output. The invisible light signal is, for example, an infrared light signal.

  The white adjustment unit 106 multiplies each visible light signal output from the visible light signal generation unit 104 by each gain designated by the control unit 110 to be described later, performs white balance correction, and outputs the result. In the white balance correction, the white balance is corrected by changing the ratio of signals related to color, for example, a red signal, a green signal, and a blue signal, in each visible light signal.

  The image synthesis unit 107 synthesizes the invisible light signal output from the invisible light signal generation unit 105 with each visible light signal output from the white adjustment unit 106, and outputs a composite signal for each predetermined wavelength component. . The composite signal of a predetermined wavelength component is, for example, a red composite signal corresponding to a red signal + infrared light signal, a green composite signal corresponding to a green signal + infrared light signal, and a blue composite corresponding to a blue signal + infrared light signal. A white composite signal corresponding to the signal and the white signal + infrared light signal.

The luminance signal generation unit 108 outputs a luminance signal generated by performing a combining process of adding the respective combined signals output from the image combining unit 107 at a predetermined ratio. The color difference signal generation unit 109 selects a composite signal related to color from each composite signal output by the image composition unit 107, for example,
A red color composite signal, a green color composite signal, and a blue color composite signal are selected, a composite process using a conversion formula for converting the total composite signal into a color difference signal is performed, and a color difference signal is output.

  The white balance detection unit 111 analyzes the color signal that is each visible light signal output from the visible light signal generation unit 104, and outputs a white balance deviation amount, color difference information, and the like.

  The visible light amount detection unit 112 detects each visible light signal output from the visible light signal generation unit 104, performs a detection process on the magnitude of the visible light signal, and outputs information on the magnitude of the visible light signal amount. The detection processing of the magnitude of the visible light signal includes, for example, information on the magnitude of the visible light signal amount by adding the signal levels within one screen of each visible light signal and dividing the addition result by the number of visible light signals. And

  The invisible light amount detection unit 113 detects the invisible light signal output from the invisible light signal generation unit 105, performs detection processing of the size of the invisible light signal, and information on the size of the invisible light signal amount Is output. In the detection processing of the magnitude of the invisible light signal, for example, the signal level in one screen of the invisible light signal is added, and the addition result is used as information regarding the magnitude of the visible light signal amount.

  For example, the signal level detection unit 114 performs integration of each pixel signal output from the signal processing unit 103 or detection of a peak value, and acquires information related to brightness of a captured image or brightness such as contrast.

  The light source unit 116 is, for example, an invisible infrared light source having a function capable of adjusting the amount of light, and is controlled by applying a voltage corresponding to a light amount control parameter set by the control unit 110 described later to the light emitting unit, for example. The subject is irradiated with the amount of light.

  The control unit 110 analyzes the white balance deviation amount, color difference information, and the like of the white balance detection unit 111, and performs processing for calculating the gain value of each signal set in the white adjustment unit 106 so that the output image has an appropriate white balance. The white adjustment unit 106 is set.

  In addition, the control unit 110 performs exposure control of the imaging unit 101 based on information relating to the brightness output from the signal level detection unit 114 based on a program incorporated in the control unit 110, a brightness target value, and the like. For the exposure control of the imaging unit 101, for example, an exposure control parameter set in the imaging unit 101 is used. As the exposure control parameters, for example, the lens aperture, shutter speed, and amplifier gain parameters of the image capturing unit 101 are set in the image capturing unit 101, the light amount input to the image capturing unit 101, and the signal level of the pixel signal output from the image capturing unit 101. To control. Here, for example, the control unit 110 stores the relationship between the exposure control parameter, the output information of the signal level detection unit 114, and the amount of light of the subject in advance, so that the control unit 110 sets the exposure control set in the imaging unit 101. The absolute amount of the light amount of the subject can be calculated from the parameter and the output information of the signal level detection unit 114.

  Furthermore, for example, information on an appropriate amount of infrared light with respect to the absolute amount of visible light is set in the control unit 110 in advance. Infrared light is not necessary when the visible light amount is sufficient, but when the visible light amount is small, the imaging device of the present invention is effective for generating an image with little noise. If it is increased, it will be difficult to express the color of the subject. The imaging unit 101 obtains an image with the best visibility in terms of the balance between the noise amount of the image to be generated and the color reproducibility, corresponding to the absolute amount of the visible light amount. Set. The appropriate infrared light amount may be set in advance in the control unit 110, or a memory unit is provided in the imaging apparatus, and the control unit 110 reads the set value set in the memory unit, so that the appropriate infrared light amount is obtained. You may get. In addition, when the relationship between the absolute amount of visible light and the appropriate infrared light amount is expressed by a relational expression, for example, the control unit 110 calculates the appropriate infrared light quantity from the relational expression. For example, when an appropriate infrared light amount corresponding to a visible light amount within a certain range is set, the control unit 110 selects an appropriate infrared light amount corresponding to the absolute amount of visible light.

  The control unit 110 calculates the ratio of visible light and infrared light components from the detection result of the visible light amount detection unit 112 and the detection result of the invisible light amount detection unit 113, and sets the calculated visible light ratio and the imaging unit 101. The absolute amount of visible light and the absolute amount of infrared light are calculated from the exposure control parameter and the output information of the signal level detection unit 114 from the absolute amount of the amount of light of the subject, and the control unit 110 corresponding to the calculated absolute amount of visible light. A target infrared light amount is calculated or selected from a preset appropriate infrared light amount. If the light amount of the infrared light component calculated earlier is smaller than the target infrared light amount, the control unit 110 increases the light amount of the infrared component calculated earlier so that the light amount emitted from the light source unit 116 is increased. If the amount of light is greater than the amount of light, the light amount control parameter of the light source unit 116 is set so that the amount of light emitted from the light source unit 116 is reduced, thereby irradiating the subject with an appropriate amount of infrared light.

  As described above, in the imaging apparatus of the present invention, the parameters set in the imaging unit 101 and the outputs of the signal level detection unit 114, the visible light amount detection unit 112, and the invisible light amount detection unit 113, the light source unit 116 applies to the subject. By controlling the amount of infrared light with an appropriate amount of light, it is possible to provide an imaging device that generates an image with high color reproducibility and good visibility even when the amount of visible light increases or decreases.

  Although the imaging apparatus of the present invention has been described above, the circuit configuration is not limited. For example, the signal level detection unit 114 is a unit that acquires information about brightness of a captured image or brightness such as contrast. In the control unit 110, for example, a combination of the output information of the visible light amount detection unit 112 and the output information of the invisible light amount detection unit 113 is used as information related to brightness for exposure control and calculation of the absolute value of the light amount. Also good. With this method, the circuit scale can be reduced. For example, the white balance detection unit 111 employs a method in which the visible light amount detection unit 112 detects each color signal, and the control unit 110 determines the amount of white balance deviation from the difference between detection results of each color signal. good. With this method, the circuit scale can be reduced.

  Hereinafter, an example of each part constituting the imaging unit 101 will be described in detail with reference to the drawings.

  FIG. 2 is a diagram illustrating a configuration illustrating an example of the imaging unit 101. The same elements as those in FIG. The imaging unit 101 includes, for example, an optical unit 200 including a lens unit 201 and a diaphragm 202, an image sensor unit 203, an amplification unit 204 that amplifies a signal level, and an AD conversion unit 205 that converts an analog signal into a digital signal. Consists of. The lens unit 201 is a lens group including, for example, an imaging lens, a zoom lens, and a focus lens, and adjusts the amount of light output from the optical unit 200 by opening and closing the diaphragm 202.

  Incident light entering the imaging unit 101 enters the image sensor unit 203 through the optical unit 200. In the image sensor unit 203, the control unit 110 performs photoelectric conversion and outputs a signal corresponding to the amount of light received by the image sensor unit 203. The amplifying unit 204 amplifies the signal output from the image sensor unit 203. The AD conversion unit 205 converts the analog signal amplified by the amplification unit 204 into a digital signal.

  The level of the signal output from the imaging unit 101 is controlled by adjusting the aperture 202 of the optical unit 200, the exposure time of the image sensor unit 203, and the gain of the amplification unit 204, for example. If the subject has the same brightness, the level of the signal output from the imaging unit 101 can be output by setting the exposure time of the diaphragm 202 and the image sensor unit 203 of the optical unit 200 and the gain of the amplification unit 204 to the same value. Signal levels to be equalized. Therefore, by measuring the amount of light of the subject in advance, the absolute amount of light of the subject can be obtained from the exposure time of the diaphragm 202 and the image sensor unit 203 of the optical unit 200, the gain of the amplification unit 204, and the signal level.

  In a surveillance camera application that captures a dark subject such as at night, since the exposure time of the image sensor unit 203 is shorter than the frame rate of the image in moving images, the aperture 202 of the optical unit 200 is opened and the gain of the amplification unit 204 is increased. There are many cases to do. Furthermore, the visibility of the output image of the imaging apparatus is improved even in a dark subject such as at night using infrared light which is invisible light.

  FIG. 3 shows an example of the color filter array of the image sensor unit 203 using infrared light in this embodiment. 301 is a color filter RIR sensitive to red light and infrared light, 302 is a color filter GIR sensitive to green light and infrared light, 303 is a color filter BIR sensitive to blue light and infrared light, 304 is The color filter WIR has sensitivity to visible light and infrared light from blue to red light. By giving each color filter sensitivity to infrared light, the signal level output from the imaging unit 101 can be increased even in a dark subject such as at night.

  FIG. 4 shows an example of the spectral characteristics of the color filter described in FIG.

  For example, the RIR pixel in which the color filter RIR301 is arranged has sensitivity in the vicinity of the red wavelength of visible light and the wavelength of the infrared light, and the GIR pixel in which the color filter GIR302 is arranged is in the vicinity of the green wavelength of visible light. A BIR pixel having sensitivity in the vicinity of each wavelength of infrared light and having the color filter BIR303 arranged has sensitivity in each of the vicinity of the blue wavelength of visible light and the wavelength of infrared light, and the color filter WIR304 is arranged. The WIR pixel has sensitivity in the vicinity of wavelengths of visible red, green, blue and infrared light. The signal processing unit 103 in the present embodiment performs demosaic processing by interpolation processing or the like on the output image signal of the image sensor unit 203 arranged with different color filters. For example, since there are no GIR pixel, BIR pixel, and WIR pixel at the pixel position of a certain RIR pixel, an interpolation signal is generated and output by interpolation processing from the same color pixels around each neighborhood. The visible light signal generation unit 104 in this embodiment generates and outputs a visible light signal by a matrix operation or the like for the pixel signal output from the signal processing unit 103, and the non-visible light signal generation unit 105 A non-visible light signal is generated and output from the pixel signal output from the processing unit 103 by matrix calculation or the like.

  FIG. 5 shows an example of the light amount control of the light source unit 116. The horizontal axis is the visible light amount irradiated to the subject, the vertical axis is the infrared light amount irradiated to the subject, and 501 is an appropriate red amount that is the infrared light amount that provides the best visibility of the output image with respect to the visible light amount. The external light quantity, 502 is the ambient infrared light that is the infrared light applied to the subject when no light is emitted from the light source unit 116, and 503 is the target light quantity of the infrared light applied to the subject from the light source unit 116. Show.

  The controller 110 sets the exposure control parameters set in the imaging unit 101 for the appropriate infrared light amount 501 corresponding to the absolute amount of the visible light amount obtained from the exposure control parameter set in the imaging unit 101 and the detection result of the visible light amount detection unit 112. When the absolute amount of the infrared light amount is small so that the absolute amount of the infrared light amount obtained from the detection result of the invisible light amount detection unit 113 matches the parameter, the infrared light amount irradiated from the light source unit 116 is increased. When the infrared light amount obtained from the exposure parameter set in the imaging unit 101 and the detection result of the invisible light amount detection unit 113 is large, the light source unit is controlled by the light source control parameter so that the infrared light amount emitted from the light source unit 116 is reduced. 116 is controlled.

  As described above, in the imaging apparatus of the present invention, an image with good visibility can be obtained by setting the amount of infrared light emitted from the light source unit 116 to an amount appropriate for the visible light amount of the subject.

  In FIG. 5, the relationship between the visible light amount and the appropriate infrared light amount 501 is shown linearly, but the relationship between the visible light amount and the appropriate infrared light amount 501 is not limited to a linear shape and becomes nonlinear depending on the characteristics of the image sensor. There is a case.

  FIG. 6 is a flowchart showing an example when the imaging method according to the present invention is implemented by a program. Step S201 that acquires an image for one frame using an image sensor that can shoot the light emitted from the subject into a predetermined wavelength component, and performs signal processing from the image shot in step S201. Thus, step S202 for separating the image signal corresponding to the visible light component (visible light signal) and the image signal corresponding to the invisible light component (non-visible light signal), and visible light among the signals output from step S202. Step S203 for analyzing the absolute amount of visible light and the absolute amount of invisible light irradiated on the subject from the signal and the exposure parameter, and a step for calculating an appropriate amount of infrared light from the absolute amount of visible light analyzed in step S203. S204 compares the appropriate infrared light amount calculated in step S204 with the invisible light signal level separated in step S202. When the infrared light quantity is not appropriate (NO) as a result of comparison in step S205 and step S205, step S206 for adjusting the light quantity when the light source is turned on / off and on, and the invisible light separated in step S202. Step S207 for adjusting the gain of the optical signal to adjust the infrared light amount, Step S208 for combining each of the visible light signal and the invisible light signal separated in Step S202, and the visible light signal / invisible light Step S209 for generating image data having color information such as an RGB image and a YUV image from the image synthesized in the optical signal synthesis step S208.

  With the processing flow described above, in the imaging apparatus of the present invention, an image with good visibility can be obtained by setting the amount of infrared light emitted from the light source unit 116 to an amount appropriate for the visible light amount of the subject. .

  FIG. 7 is an example of a block diagram illustrating the overall configuration of the imaging apparatus according to the second embodiment. The same components as those in FIG.

  Reference numeral 701 denotes an invisible light adjusting unit. For example, the invisible light adjustment unit 701 multiplies the invisible light signal output from the invisible light signal generation unit 105 by the gain designated by the control unit 110 and outputs the result. When the amount of invisible light is large, the ratio of the invisible light signal level to the visible light signal level can be lowered by reducing the level of the invisible light signal in the invisible light adjusting unit 701. The output video can be improved in color reproducibility.

  Hereinafter, a control method of the control unit 110 that determines the gain of the invisible light adjusting unit 701 will be described with reference to the drawings.

  FIG. 8 shows an example of control of the light source unit 116 and the invisible light adjusting unit 701. In FIG. 8, invisible light will be described by taking infrared light as an example.

  In FIG. 8, (1) is the same as in FIG. The threshold 1 is applied to the subject even if the infrared light source is not turned on and the appropriate infrared light amount 501 that is an appropriate infrared light amount for generating a video with good visibility with respect to the visible light amount irradiated to the subject. If the ambient infrared light amount 502 is equal, and the visible light amount irradiated to the subject is larger than the threshold 1, infrared irradiation from the infrared light source is unnecessary and the increase in the visible light amount Accordingly, it is indicated that the color reproducibility is better when the ambient infrared light amount 502 is also reduced. The threshold 2 indicates a visible light amount that is sufficient for generating a video with good visibility and that does not require infrared light. In order to improve the visibility of the image output from the imaging apparatus, for example, the signal level of invisible light is lowered from the threshold value 1 and the signal level is controlled to be minimized at the threshold value 2.

  Reference numeral 801 in FIG. 8B indicates an example of a gain set by the control unit 110 in the invisible light adjustment unit 701. In the control unit 110, when the invisible light signal level output from the invisible light signal generation unit 105 is small in the amount of visible light, the gain of the invisible light adjustment unit 701 is set to 1 and the signal level corresponding to the infrared light amount Is used. Here, in the region where the gain of the invisible light adjusting unit 701 is 1, the invisible light signal level is controlled by increasing / decreasing the amount of infrared light applied to the subject from the light source unit 116. When the visible light amount exceeds the threshold value 1, the gain of the infrared light adjustment unit is lowered according to the increase in the visible light amount, and the threshold value 2 is set to the minimum value. In the control unit 110, the invisible light adjustment unit 701 controls the invisible light signal level, so that the visible light amount from the light source unit 116 to the visible light amount that does not require the infrared light amount is transferred to the image composition unit 107. The ratio of the invisible light component to the input visible light component can be controlled, and the color reproducibility of the image output from the image device can be improved.

  By providing the non-visible light adjustment unit 701 with the imaging apparatus described above, an image with high visibility can be obtained from a low illuminance requiring a light source to a high illuminance subject not requiring infrared light.

  Note that threshold values 1 and 2 shown in (2) of FIG. 8 are not fixed and may vary depending on the shooting environment. Further, the relationship between the visible light amount and the infrared light gain is an example, and may vary depending on the characteristics of the imaging unit 101 and the imaging environment, and is not limited to the illustrated relationship.

  FIG. 9 shows a processing flow showing an example when the imaging method of the present invention is implemented by a program. The same components as those in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted.

  The control unit 110 calculates the appropriate infrared light amount 501 in step S204, and reduces the light amount of the light source unit 116 in step S206 when the appropriate infrared light amount calculation result is larger than the detection result acquired by the invisible light amount detection unit 113. The light source control parameters are set as follows. Here, for example, when the light amount of the light source unit 116 is minimum or the light source is off, the control unit 110 calculates an appropriate gain of the invisible light adjustment unit 701 in step S901 and sets the gain to the invisible light adjustment unit 701. .

  As described above, when the invisible light amount irradiated to the subject is larger than the necessary invisible light amount, the invisible light adjustment unit 701 reduces the signal level with respect to the infrared light amount and By reducing the ratio between the input visible light signal level and the non-visible light signal level, an image with good color reproducibility can be obtained.

  In the above description, the color difference signal generation unit 109 for generating a color is described as an example arranged after the image synthesis unit 107. However, the color difference signal generation unit 109 generates an invisible light signal component when generating a color signal. Since no subtraction occurs, the same color signal can be obtained even if the output signal of the white adjustment unit 106 is used.

  In the present embodiment, an example in which there is a difference in the visible light amount and the invisible light amount in the subject will be described below. In this embodiment, invisible light is described as infrared light.

  FIG. 10 is an example of a subject. Reference numeral 1000 denotes a range imaged by the imaging apparatus, reference numerals 1001 and 1002 denote subjects to be imaged. For example, reference numeral 1001 denotes an object close to the imaging apparatus, and reference numeral 1002 denotes an object far from the imaging apparatus. When there is a visible light source only near the subject 1001, the visible light amount of the subject 1001 is larger than the visible light amount of the subject 1002, and the appropriate infrared light amount varies depending on the subject. In addition, the infrared light amount irradiated to the subject by the light source unit 116 is determined by the infrared light amount output from the light source unit 116 and the distance between the light source unit 116 and the subject. Even when irradiated, the infrared light quantity received by the subject 1001 and the infrared light quantity received by the subject 1002 are different. Therefore, in order to output a subject within one screen imaged by the imaging apparatus as a video with good visibility, the gain of the invisible light adjusting unit 701 is controlled for each pixel. Hereinafter, the control method will be described.

  FIG. 11 is an example of a block diagram illustrating the overall configuration of the imaging apparatus according to the third embodiment. The same components as those in FIGS. 1 and 7 are denoted by the same reference numerals, and description thereof is omitted.

  First, the control unit 110 determines the amount of infrared light emitted from the light source unit 116. As a determination method, for example, an appropriate infrared light amount 501 for controlling the light source unit 116 is determined from the exposure parameter set from the detection result of the signal level detection unit 114 and the detection result detected by the visible light amount detection unit 112. . As the detection result of the visible light amount detection unit 112 used for this determination, for example, one screen is divided into several regions, and the visible light amount detection result of the region with the smallest visible light amount is used.

  Next, the control unit 110 acquires, for example, the output signal level of the visible light signal generation unit 104 and the signal level of each pixel of the invisible light signal generation unit 105 for each pixel, and an appropriate infrared light amount 501 for each pixel. To determine the gain of the invisible light adjusting unit 701 for each pixel.

  As an example of a method for controlling the gain of the invisible light adjusting unit 701 performed by the control unit 110, FIG. 12 shows an example of the relationship between the visible light amount of the subject and the infrared light amount when the subject 1002 is in the region with the smallest visible light amount. The same parts as those in FIG. In FIG. 12, the horizontal axis represents the visible light amount applied to the subject, the vertical axis represents the infrared light amount applied to the subject, 1101 represents the visible light amount of the subject 1001, 1102 represents the visible light amount of the subject 1002, and 1111 represents the subject 1001. Infrared light amount 1112 is the infrared light amount of the subject 1002, 1113 is the appropriate visible light / infrared light balance 1114 of the subject 1001, and the appropriate visible light / infrared light balance of the subject 1002 is shown. Here, the amount of infrared light indicates, for example, a sum of irradiation light from the light source unit 116 and ambient infrared light. In FIG. 12, the infrared light quantity 1112 with respect to the visible light quantity 1102 matches the appropriate infrared light quantity 1114 in the subject 1002, and the subject 1001 has more infrared light quantity applied to the subject 1001 than the appropriate infrared light quantity 1113. Is shown. FIG. 13 shows an example of a gain control method of the invisible light adjusting unit 701. The horizontal axis represents the difference between the infrared light amount applied to the subject and the appropriate infrared light amount obtained as in the example described with reference to FIG. 12, and the vertical axis represents the gain of the invisible light adjustment unit 701. Here, the gain when the invisible light signal level is output without adjusting the invisible light signal level by the invisible light adjusting unit 701 is set to 1. The control unit 110 sets the gain to 1 when there is no difference between the infrared light amount applied to the subject and the appropriate infrared light amount, and gain as the difference between the infrared light amount applied to the subject and the appropriate effect amount increases. The control which lowers is performed. In FIG. 13, in consideration of noise amplification, when the appropriate infrared light amount is larger than the infrared light amount irradiated to the subject, the gain is controlled to be 1. However, the gain is increased to compensate for the shortage. You may enlarge it.

  As described above, in the imaging apparatus of the present invention, the light amount of the light source unit 116 and the gain of the invisible light adjusting unit 701 are set to the absolute amount of visible light, the visible light amount and the invisible light amount in the screen, By controlling the control unit 110 based on the visible light signal level and the non-visible light signal level, even if there is a variation in the visible light amount within one screen of the video imaged by the imaging device of the present invention, the image synthesis unit 107 The input non-visible light signal level can be made appropriate, and an image with good color reproducibility can be generated.

  In this embodiment, the control in units of pixels has been described. However, when there is a decrease in visibility such as a pseudo contour due to a sudden change in gain between pixels, for example, a low-pass filter is provided, The gain change may be moderated. Further, the control may be such that one screen is divided into several blocks and the gain is determined in units of blocks.

  FIG. 14 is an example of a block diagram illustrating the overall configuration of the imaging apparatus according to the fourth embodiment. The same components as those in FIG.

Reference numeral 1401 denotes a filter unit, and 1402 denotes a light source unit.
The filter portion 1401 is configured by a liquid crystal panel or the like that can change the light transmittance, and the amount of light emitted from the light source portion 1402 can be adjusted by changing the light transmittance.
The light source unit 1402 is, for example, an infrared light source capable of at least on / off control.

  In the first embodiment, the amount of light output from the light source unit 116 is changed. In this embodiment, the infrared light amount irradiated to the subject is adjusted by changing the transmittance of the filter unit 1401.

  FIG. 15 shows an example of control of the light source unit 1402 and the filter unit 1401. In FIG. 15, (1) is the same as in FIG.

  In FIG. 15, the horizontal axis of (2) is the visible light amount irradiated to the subject, the vertical axis is the transmittance of the filter unit 1401, and 1501 is the transmittance controlled by the control unit 110 according to the visible light amount irradiated to the subject. Is shown. When the amount of visible light is small, the transmittance of the filter unit 1401 is increased and much of the infrared light of the light source unit 1402 is used. As the visible light amount increases and the required infrared light decreases, the transmittance of the filter unit 1401 is lowered, and the components of the infrared light input to the luminance signal generation unit 108 and the color difference signal generation unit 109 are reduced. With the above control, the amount of infrared light emitted from the light source to the subject can be adjusted, and an image with good visibility can be obtained as in the first embodiment. Further, by providing the invisible light adjusting unit 701 as in the second and third embodiments, the same effect can be obtained.

  DESCRIPTION OF SYMBOLS 101 ... Imaging part, 103 ... Signal processing part, 104 ... Visible light signal generation part, 105 ... Non-visible light signal generation part, 106 ... White adjustment part, 107 ... Image composition 108: Luminance signal generator 109: Color difference signal generator 110 110 Controller 111 White balance detector 112 112 Visible light detector 113 Non Visible light amount detection unit, 114... Signal level detection unit, 116... Light source unit, 201... Lens unit, 202. ... AD converter, 701 ... Invisible light adjustment unit

Claims (6)

An imaging unit that has sensitivity to visible light and invisible light, and outputs an optical image received with a set imaging parameter as an electrical signal;
A visible light signal generator for extracting a visible light signal from the electrical signal;
A non-visible light signal generation unit that extracts a non-visible light signal from the electrical signal;
A signal detector that outputs brightness information from the electrical signal; a visible light detector that detects visible light luminance information by detecting the visible light signal;
A non-visible light detection unit that detects the non-visible light signal and outputs non-visible light luminance information;
A light source capable of controlling the amount of invisible light to be irradiated;
A control unit configured to set the imaging parameter in the imaging unit from the brightness information;
The said control part controls the said imaging parameter and the light quantity which the said light source irradiates based on the said visible light luminance information and the said invisible light luminance information. The imaging apparatus according to claim 1,
The invisible light is infrared light;
The imaging unit includes an image sensor that photoelectrically converts light from a subject including visible light and infrared light through a plurality of filters having transmission characteristics arranged in units of pixels and outputs the result as a pixel signal. An imaging device. The imaging apparatus according to claim 1,
The control unit stores information associating the absolute amount of visible light with a predetermined invisible light amount,
The control unit is configured to approximate the predetermined invisible light amount corresponding to the absolute amount of visible light amount calculated from the imaging parameter set in the imaging unit and the visible light luminance information output from the visible light detection unit. An image pickup apparatus that controls the amount of light emitted from the camera. The imaging device according to claim 1,
A non-visible light signal adjustment unit for adjusting the gain of the non-visible light signal;
An image pickup apparatus, further comprising: an image synthesis unit that synthesizes the visible light signal and the invisible light signal whose gain is adjusted by the invisible light signal adjustment unit. The imaging apparatus according to claim 4.
The visible light detection unit divides the visible light signal into a plurality of areas, calculates a visible light amount for each area,
The control unit controls the light amount of the light source in accordance with the area with the smallest visible light amount, and controls the gain of the invisible light adjustment unit based on the level of the visible light signal and the level of the invisible light signal. An imaging apparatus characterized by: An imaging unit that has sensitivity to visible light and invisible light, and outputs an optical image received with a set imaging parameter as an electrical signal;
A visible light signal generator for extracting a visible light signal from the electrical signal;
A non-visible light signal generation unit that extracts a non-visible light signal from the electrical signal;
A signal detector that outputs brightness information from the electrical signal; a visible light detector that detects visible light luminance information by detecting the visible light signal;
A non-visible light detection unit that detects the non-visible light signal and outputs non-visible light luminance information;
A light source that emits invisible light;
A filter unit capable of controlling the transmittance of invisible light emitted by the light source;
A control unit configured to set the imaging parameter in the imaging unit from the brightness information;
The said control part controls the said imaging parameter and the transmittance | permeability of the said filter part based on the said visible light luminance information and the said non-visible light luminance information, The imaging device characterized by the above-mentioned.

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