JP2017062921A - Illuminance calculation device, illumination control system and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminance calculation device that can calculate high-precision illuminance even when an image is used for a processing function of calculating illuminance and other processing functions.SOLUTION: An illuminance calculation device 10 includes a processor 13. The processor 13 has a first processing function of correcting an image captured by an imaging unit 11 to calculate the illuminance of a space as an imaging target of the imaging unit 11, and a second processing function for correcting the image to perform processing different from the calculation of the illuminance. When executing the first processing function, the processor 13 is configured to use a correction value different from the correction value used in the second processing function.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an illuminance calculation device, an illumination control system, and a program.

  2. Description of the Related Art Conventionally, there are apparatuses that detect the brightness of a space to be imaged and the presence or absence of a person using a captured image, and a system that controls a lighting fixture using the detection result of the apparatus (see Patent Document 1). ).

  In the illumination control device (illuminance calculation device) described in Patent Document 1, an image that has been subjected to the same correction processing based on exposure time, gain, and the like is used for space brightness detection and human presence / absence detection.

JP 2014-102909 A

  When detecting the presence or absence of a person, it is necessary to distinguish whether a photographed object is a person or a background, and therefore a certain level of brightness is required. A conventional illumination control device (illuminance calculation device) must be brightened by correction when a photographed image is dark. In this case, even if the brightness is detected in the corrected image, it is often different from the actual brightness (illuminance). Therefore, there exists a problem that the precision of the brightness (illuminance) detected with the conventional illumination control apparatus (illuminance calculation apparatus) is low.

  Therefore, the present invention has been made in view of the above reasons, and the purpose thereof is to calculate highly accurate illuminance even when the image is used for a processing function for calculating illuminance and other processing functions. An object of the present invention is to provide an illuminance calculation device, a lighting control system, and a program that can be used.

  An illuminance calculation apparatus according to the present invention corrects an image captured by an imaging unit to calculate an illuminance of a space that is an imaging target of the imaging unit, and corrects the image to calculate the illuminance. A processing unit having a second processing function for performing processing different from that of the first processing function, and the processing unit uses a correction value different from the correction value used in the second processing function when executing the first processing function. It was configured as described above.

  The illumination control system according to the present invention includes the illuminance calculation device, the luminaire, and a control device that controls dimming of the luminaire using the illuminance calculated by the illuminance calculation device. It is characterized by.

  Further, the program according to the present invention includes a first processing function for calculating an illuminance of a space that is a photographing target of the imaging unit by correcting an image captured by the imaging unit, and correcting the image to obtain the illuminance. When the first processing function is performed in the processing unit, the correction value is different from the correction value used in the second processing function when the first processing function is performed in the processing unit. Is used.

  According to the illuminance calculation device, the illumination control system, and the program described above, it is possible to calculate illuminance with high accuracy even when the image is used for a processing function for calculating illuminance and other processing functions.

It is a block diagram explaining the structure of the illumination control system and illuminance calculation apparatus in Embodiment 1. 5 is a flowchart for explaining correction coefficient calculation processing performed by the illuminance calculation apparatus according to the first embodiment. 5 is a flowchart illustrating luminance correction processing performed by the illuminance calculation apparatus according to the first embodiment. FIG. 4A is a diagram for explaining the transmittance of a lens, and FIG. 4B is a diagram for explaining correction coefficients corresponding to a plurality of pixels. It is a flowchart explaining the process of the brightness correction which the illuminance calculation apparatus in Embodiment 2 performs.

  The following embodiments generally relate to an illuminance calculation device, an illumination control system, and a program, and more particularly to an illuminance calculation device, an illumination control system, and a program that calculate illuminance of a space to be imaged using a captured image.

(Embodiment 1)
Here, the illumination control system 1, the illuminance calculation device 10, and the program according to the present embodiment will be described with reference to FIGS.

  As illustrated in FIG. 1, the illumination control system 1 includes an illuminance calculation device 10, a control device 20, and a plurality of lighting fixtures 30. In addition, the lighting fixture 30 may be one.

  The illuminance calculation device 10 has a function (first processing function) for calculating the illuminance of the space to be imaged using the captured image and a function (second processing function) for detecting the presence or absence of a person in the space to be imaged. It is a device that has. The control device 20 is a device that controls dimming of the plurality of lighting fixtures 30 based on the processing result of the first processing function and the processing result (detection result) of the second processing function.

  Hereinafter, the configuration of the illuminance calculation apparatus 10 will be described. As illustrated in FIG. 1, the illuminance calculation device 10 includes an imaging unit 11, a storage unit 12, a processing unit 13, and a communication unit 16.

  The imaging unit 11 is a two-dimensional image sensor having a solid-state imaging element in which a plurality of light receiving elements are two-dimensionally arranged. Here, the light receiving element is a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like.

  The imaging unit 11 outputs the captured image to the illuminance calculation unit 14 and the detection unit 15 of the processing unit 13 described later. The imaging unit 11 outputs the exposure time and gain of the captured image to the illuminance calculation unit 14 and the detection unit 15. Further, the imaging unit 11 outputs the white balance of the captured image to the illuminance calculation unit 14. Here, the white balance includes a white balance value α1 for R luminance, a white balance value β1 for G luminance, and a white balance value γ1 for B luminance.

  The storage unit 12 is a memory that stores a coefficient (visibility coefficient) according to human visibility characteristics. Specifically, the storage unit 12 stores a visibility coefficient a for R brightness, a visibility coefficient b for G brightness, and a visibility coefficient c for B brightness. Further, the storage unit 12 stores a conversion coefficient to be described later.

  The processing unit 13 has, for example, a microcomputer (microcontroller) as a main configuration, and realizes a desired function by executing a program stored in the memory. Note that the program may be written in a memory in advance or may be provided by being stored in a recording medium such as a memory card. As illustrated in FIG. 1, the processing unit 13 includes an illuminance calculation unit 14 that executes the first processing function and a detection unit 15 that executes the second processing function.

  The illuminance calculation unit 14 performs calibration when the illuminance calculation device 10 is installed, calculates a conversion coefficient for converting the luminance of the image into illuminance, and writes the conversion coefficient in the storage unit 12. Specifically, the illuminance calculation unit 14 calculates the conversion coefficient using the calculation formula “conversion coefficient = (exposure time × gain × brightness coefficient) / image brightness”. Here, the brightness coefficient is a value measured by an illuminometer.

  The illuminance calculation unit 14 uses the white balance values α1, β1, and γ1 acquired from the imaging unit 11 and the visibility coefficients a, b, and c stored in the storage unit 12 to use correction coefficients α2, β2 and γ2 are calculated. Here, α2 = a / α1, β2 = b / β1, and γ2 = c / γ1.

  The illuminance calculation unit 14 acquires YUV components of a plurality of pixels included in the image acquired from the imaging unit 11. The illuminance calculation unit 14 performs inverse gamma conversion and RGB conversion on the acquired YUV component to calculate R luminance (R1), G luminance (G1), and B luminance (B1) in each of the plurality of pixels. The illuminance calculation unit 14 corrects the calculated R1, G1, and B1 using the coefficients α2, β2, and γ2, and acquires the corrected R luminance (R2), G luminance (G2), and B luminance (B2). . Here, R2 = R1 × α2, G2 = G1 × β2, and B2 = B1 × γ2. The illuminance calculation unit 14 calculates the brightness (pixel luminance) of each pixel using the corrected luminance of the pixel. Here, the calculation formula of the pixel luminance is “pixel brightness = (R2 + G2 + B2) / (exposure time × gain)”.

  Originally, in the image captured by the imaging unit 11, R luminance, G luminance, and B luminance are corrected by white balance. When R luminance, G luminance, and B luminance before white balance correction are R0, G0, and B0, R1, G1, and B1 described above are R1 = R0 × α1, G1 = G0 × β1, and B1 = B0 × γ1. It becomes. Then, the corrected R luminance R2 is “R2 = R1 × α2 = R0 × α1 × (a / α1) = R0 × a”. The corrected G luminance G2 is “G2 = G0 × b”, and the corrected B luminance B2 is “B2 = B0 × c”. That is, each luminance of RGB before correction is corrected by the visibility coefficient, and the corrected R luminance, G luminance, and B luminance are luminances that match human visual sensitivity. In the following description, R luminance, G luminance, and B luminance before white balance correction are referred to as original R luminance, G luminance, and B luminance.

  The illuminance calculation unit 14 calculates a representative value by using “pixel brightness” (pixel luminance) calculated for each pixel. Specifically, the illuminance calculation unit 14 calculates an average value of all the calculated pixel luminances, and uses the calculated average value as the image brightness (image luminance). Note that the illuminance calculation unit 14 may calculate an average value of a plurality of pixel luminances included in a partial region of the image instead of using all the pixel luminances. Further, instead of calculating the average value as the representative value, it may be a median value for all the calculated pixel luminances, or may be the most frequent value (mode) among all the calculated pixel luminances. There may be. In addition, the median value and the mode value may be acquired from a plurality of pixel luminances included in a partial region of the image.

  The illuminance calculation unit 14 calculates the illuminance by multiplying the calculated luminance of the image by the conversion coefficient stored in the storage unit 12. The illuminance calculation unit 14 outputs the illuminance calculated from the luminance of the image to the control device 20 via the communication unit 16.

  The detection unit 15 detects the presence or absence of a person in the space to be imaged using the image captured by the imaging unit 11. Specifically, the detection unit 15 uses the information acquired from the imaging unit 11 to correct the image captured by the imaging unit 11 into an image for human detection. The detection unit 15 stores in advance, as a background image, an image shot in a state where no person is present in the shooting target space. The detection unit 15 compares the background image with the corrected image and detects the presence or absence of a person. The detection unit 15 outputs the detection result to the control device 20 via the communication unit 16.

  The communication unit 16 outputs the illuminance calculated by the illuminance calculation unit 14 and the detection result of the detection unit 15 to the control device 20.

  The control device 20 controls dimming of the plurality of lighting fixtures 30 using the illuminance calculated by the illuminance calculation unit 14 and the detection result of the detection unit 15.

  For example, the control device 20 controls dimming of the plurality of lighting fixtures 30 so that the brightness becomes a predetermined illuminance according to the illuminance acquired from the illuminance calculation device 10. Moreover, the control apparatus 20 may compare the illumination intensity acquired from the illumination intensity calculation apparatus 10, and a predetermined threshold value, and may control the light control of the some lighting fixture 30 according to the result. Specifically, when the illuminance acquired from the illuminance calculation device 10 is smaller than a predetermined threshold, the control device 20 performs dimming of the plurality of lighting fixtures 30 so as to increase the illuminance of the plurality of lighting fixtures 30. Control. The control device 20 controls dimming of the plurality of lighting fixtures 30 so as to reduce the illuminance of the plurality of lighting fixtures 30 when the control device 20 is larger than the predetermined threshold.

  In addition, the control device 20 controls the dimming of the plurality of lighting fixtures 30 according to the detection result of the detection unit 15 (the presence or absence of a person in the shooting target space). Specifically, the control device 20 controls the plurality of lighting fixtures 30 so that the plurality of lighting fixtures 30 are turned on when a person is present in the space to be imaged. Further, the control device 20 controls the plurality of lighting fixtures 30 so that the plurality of lighting fixtures 30 are turned off when no person is present in the space to be imaged.

  The control device 20 can perform various controls on the plurality of lighting fixtures 30 by combining the illuminance calculated by the illuminance calculation unit 14 and the detection result of the detection unit 15.

  Next, calculation of the correction coefficient executed by the illuminance calculation unit 14 will be described with reference to the flowchart shown in FIG.

  The illuminance calculation unit 14 acquires white balance values (α1, β1, γ1) from the imaging unit 11 (step S1).

  The illuminance calculation unit 14 calculates a correction coefficient α2 (= a / α1) from the white balance values α1, β1, and γ1 acquired from the imaging unit 11 and the visibility coefficients a, b, and c stored in the storage unit 12. , Β2 (= b / β1), γ2 (= c / γ1) are calculated (step S2).

  Next, the luminance correction executed by the illuminance calculation unit 14 will be described with reference to the flowchart shown in FIG.

  The illuminance calculation unit 14 acquires the YUV component of one pixel included in the image acquired from the imaging unit 11 (step S10). The illuminance calculation unit 14 performs conversion processing (step S11). Specifically, the illuminance calculation unit 14 performs inverse gamma conversion and RGB conversion on the acquired YUV component to obtain R luminance (R1), G luminance (G1), and B luminance (B1) in RGB of one pixel. calculate.

  The illuminance calculation unit 14 corrects the calculated R1, G1, and B1 using the coefficients α2, β2, and γ2, and the corrected R luminance R2 (= R1 × α2), G luminance G2 (= G1 × β2), and B luminance B2 (= B1 × γ2) is acquired (step S12).

  The illuminance calculation unit 14 calculates the brightness of one pixel (pixel luminance = (R ′ + G ′ + B ′) / (exposure time × gain)) using the corrected luminance (step S13).

  The illuminance calculation unit 14 determines whether or not there is an unprocessed pixel (a pixel that has not been corrected) among all the pixels included in the image (step S14).

  If it is determined that there is a pixel that has not been processed, that is, that has not been corrected (“Yes” in step S14), the illuminance calculation unit 14 returns to step S10, and performs the processing from step S10 onward for the unprocessed pixel.

  When it is determined that there is no unprocessed pixel, that is, all pixels have been corrected (“No” in step S14), the illuminance calculation unit 14 calculates “pixel brightness” (pixels) calculated for each pixel. The luminance of the image is calculated using (luminance) (step S15).

  The illuminance calculation unit 14 converts the calculated brightness of the image into illuminance by performing a conversion process (step S16).

  In the illuminance calculation apparatus 10 of the present embodiment, the function of detecting the presence or absence of a person is the second processing function, but is not limited to this. For example, the second processing function may be a function for detecting the presence or absence of a defect in an article included in the image. That is, the second processing function may be a processing function that uses an image for some determination (detection). When the function for detecting the presence or absence of defects in an article included in an image is the second processing function, the detection unit 15 of the illuminance calculation apparatus 10 outputs a detection result to a management apparatus that manages the article. In a management apparatus, when a detection result is the content which detected the defect of articles | goods, it alert | reports to an administrator.

  Further, the second processing function may be only a processing function for correcting an image. In this case, the processing unit 13 includes an image processing unit that corrects an image instead of the detection unit 15. The image processing unit performs correction similar to the correction performed by the detection unit 15 on the image captured by the imaging unit 11, and outputs the corrected image to the base unit of the interphone installed in the house. The interphone master unit displays the corrected image.

  In the present embodiment, the calibration is performed and the conversion coefficient is calculated when the illuminance calculation apparatus 10 is installed, but the present invention is not limited to this. Even after installation, the illuminance calculation apparatus 10 may perform calibration and update the conversion coefficient. For example, the illuminance calculation device 10 may update the conversion coefficient every predetermined period (1 month, 6 months, 1 year, etc.), or update the conversion coefficient every time the imaging unit 11 is inspected. You may go.

  In the present embodiment, the imaging unit 11 is not an essential component of the illuminance calculation device 10. In addition, the illuminance calculation device 10 and the control device 20 may be configured as an integrated device.

  As described above, the illuminance calculation device 10 of the present embodiment includes the processing unit 13. The processing unit 13 corrects the image captured by the imaging unit 11 to calculate the illuminance of the space that is the imaging target of the imaging unit 11, and performs processing different from the calculation of the illuminance by correcting the image. A second processing function to be performed (for example, a function of detecting the presence or absence of a person) When executing the first processing function, the processing unit 13 is configured to use a correction value different from the correction value used in the second processing function.

  According to this configuration, the illuminance calculation apparatus 10 performs different correction values when executing the first processing function for calculating illuminance and when executing the second processing function (for example, a function for detecting the presence or absence of a person). Is used. Therefore, the illuminance calculation apparatus 10 can use a correction value suitable for each processing function.

  For example, the illuminance calculation device 10 can accurately detect the presence or absence of a person in the shooting target space by using a white balance as a correction value to brighten the image in the function of detecting the presence or absence of a person. Furthermore, in the first processing function, the illuminance calculation apparatus 10 can calculate illuminance with high accuracy by using human visibility as a correction value.

  Here, when executing the first processing function, the processing unit 13 calculates the illuminance according to the human visual sensitivity by correcting the luminance of the image using the white balance value used for photographing the image. It is preferable to do. According to this configuration, the illuminance calculation device 10 can calculate illuminance close to the illuminance felt by a person.

  Here, it is preferable that the second processing function is a function that corrects an image and detects the presence or absence of a person in a space that is an imaging target of the imaging unit 11 using the corrected image. According to this configuration, highly accurate illuminance calculation and human detection can be performed.

  Moreover, the lighting control system 1 of this embodiment controls the light control of the lighting fixture 30 using the illuminance calculated by any one of the illuminance calculating devices 10 described above, the lighting fixture 30, and the illuminance calculating device 10. And a control device 20. According to this configuration, the illumination control system 1 can calculate highly accurate illuminance without reducing the accuracy of other processing functions (second processing function).

  Moreover, the program of this embodiment makes a computer function as the process part 13 which performs a 1st processing function and a 2nd processing function. The first processing function corrects an image captured by the imaging unit 11 and calculates the illuminance of the space that is the imaging target of the imaging unit 11. The second processing function performs processing different from the calculation of illuminance by correcting the image. When the first processing function is performed in the processing unit 13, a correction value different from the correction value used in the second processing function is used.

  According to this program, highly accurate illuminance can be calculated without reducing the accuracy of other processing functions (second processing functions).

(Embodiment 2)
In the present embodiment, the coefficient stored in the storage unit 12 of the illuminance calculation apparatus 10 is different from that in the first embodiment.

  Here, it demonstrates using FIG.4, 5 centering on a different point from Embodiment 1. FIG. Moreover, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted suitably.

  In the lens that the imaging unit 11 uses to capture an image, the light amount transmittance (peripheral light amount transmittance) decreases as the distance from the center of the lens increases (see FIG. 4A). That is, the luminance at the center of the captured image is high, and the luminance decreases as the distance from the center of the image increases.

  In the present embodiment, the illuminance calculation device 10 corrects the plurality of pixels included in the image so that the luminance is the same as when the same amount of light as the central pixel is obtained.

The storage unit 12 of the present embodiment stores correction coefficients corresponding to a plurality of pixels. For example, when the number of pixels is n × m (n pixels in the X-axis direction and m pixels in the Y-axis direction), the storage unit 12 stores n × m correction coefficients (see FIG. 4B). Here, the correction coefficient corresponding to the pixel at the coordinates (i, j) is denoted as a _ij . Here, i is an integer from 1 to n, and j is an integer from 1 to m.

The illuminance calculation unit 14 acquires the luminance component Y (i, j) of the pixel at coordinates (i, j). The illuminance calculation unit 14 corrects the luminance component Y _ij of the pixel at coordinates (i, j) using the correction coefficient a _ij . More specifically, the luminance component _{Y ij,} is multiplied by the correction coefficient _{a ij.}

  The illuminance calculation unit 14 calculates a representative value using the luminance component Y corrected for each pixel. Specifically, the illuminance calculation unit 14 calculates the average value of all corrected luminance components Y, and uses the calculated average value as the brightness of the image (the luminance of the image). The illuminance calculation unit 14 calculates the illuminance by multiplying the calculated value (average value) by the conversion coefficient stored in the storage unit 12. The illuminance calculation unit 14 outputs the calculated illuminance to the control device 20 via the communication unit 16.

  The illuminance calculation unit 14 may calculate the average value of a plurality of corrected luminance components Y included in a partial area of the image, instead of using all the luminance components Y. Further, instead of calculating the average value as the representative value, it may be a median value for all the corrected luminance components Y after correction, or the most frequent value (of all the corrected luminance components Y ( Mode). Further, the median value and the mode value may be acquired from a plurality of corrected luminance components Y included in a partial region of the image.

  Next, the luminance correction executed by the illuminance calculation unit 14 will be described with reference to the flowchart shown in FIG.

The illuminance calculation unit 14 acquires the luminance component (Y) of one pixel included in the image acquired from the imaging unit 11 (step S20). For example, the illuminance calculation unit 14 acquires the luminance component Y _ij of the pixel at coordinates (i, j).

The illuminance calculation unit 14 corrects the acquired luminance component (Y) using a corresponding correction coefficient. Specifically, the illuminance calculation unit 14 multiplies the luminance component Y _ij by the correction coefficient a _ij .

  The illuminance calculation unit 14 determines whether or not there is an unprocessed pixel (a pixel that has not been corrected) among all the pixels included in the image (step S21).

  If it is determined that there is a pixel that has not been processed, that is, that has not been corrected (“Yes” in step S21), the illuminance calculation unit 14 returns to step S20, and performs the processing from step S20 onward for the unprocessed pixel.

  When it is determined that there is no unprocessed pixel, that is, all pixels are corrected (“No” in step S21), the illuminance calculation unit 14 uses the luminance component Y corrected for each pixel to generate an image. Is calculated (step S22).

  The illuminance calculation unit 14 converts the calculated luminance of the image into illuminance by performing a conversion process (step S23).

  In the present embodiment, the illuminance calculation unit 14 corrects the luminance of the image, instead of using a coefficient (visibility coefficient) corresponding to the human visibility characteristic, a correction coefficient corresponding to the peripheral light amount transmittance. However, the present invention is not limited to this. The illuminance calculation unit 14 may correct the brightness of the image using both the visibility coefficient and the correction coefficient corresponding to the peripheral light amount transmittance.

  In this case, the illuminance calculation unit 14 corrects each pixel with a correction coefficient corresponding to the peripheral light amount transmittance. Thereafter, the illuminance calculation unit 14 calculates the R luminance, G luminance, and B luminance of the corrected pixel from α2 (= a / α1), β2 (= b / β1), and γ2 (= c / Each correction is performed with γ1).

  As described above, in the illuminance calculation apparatus 10 according to the present embodiment, when executing the first processing function, the processing unit 13 uses the peripheral light amount attenuation rate in the lens used for image capturing to determine the brightness of the image. It is preferable to calculate the illuminance corresponding to the human visibility by correcting the above. According to this configuration, the illuminance calculation device 10 can calculate illuminance close to actual illuminance.

  The lighting control system and program described in the first embodiment can apply the configuration and operation of the second embodiment described above, and can obtain the same effects as described above.

DESCRIPTION OF SYMBOLS 1 Illumination control system 10 Illuminance calculation apparatus 11 Imaging part 13 Processing part 20 Control apparatus 30 Lighting fixture

Claims (6)

A first processing function that corrects an image captured by the imaging unit to calculate the illuminance of a space that is an imaging target of the imaging unit, and a second process that corrects the image and performs processing different from the calculation of the illuminance A processing unit having a function;
The illuminance calculation apparatus according to claim 1, wherein the processing unit is configured to use a correction value different from a correction value used in the second processing function when the first processing function is executed. When the first processing function is executed, the processing unit uses the white balance value of the imaging unit and corrects the luminance of the image so as to match a human visual sensitivity. 1. The illuminance calculation device according to 1. When executing the first processing function, the processing unit corrects the luminance of the image so as to match a human visibility using a peripheral light amount attenuation rate in the lens of the imaging unit. The illuminance calculation apparatus according to claim 1 or 2. The second processing function is a function of correcting the image and detecting the presence or absence of a person in a space that is a photographing target of the imaging unit using the corrected image. The illumination intensity calculation apparatus as described in any one. The illuminance calculation device according to any one of claims 1 to 4,
Lighting fixtures;
A lighting control system comprising: a control device that controls dimming of the lighting fixture using the illuminance calculated by the illuminance calculating device. Computer
A first processing function that corrects an image captured by the imaging unit to calculate the illuminance of a space that is an imaging target of the imaging unit, and a second process that corrects the image and performs processing different from the calculation of the illuminance A program in which a correction value different from a correction value used in the second processing function is used when the first processing function is performed in the processing unit.

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