Illumination system and illumination control method

Abstract

This illumination system comprises: an illumination light source selection unit that selects a combination of light sources that satisfy a target value of the enhancement or suppression of a color to be enhanced or suppressed and can synthesize a reference illumination light; and an output unit that causes each light source to be used to emit light on the basis of a combination of the selected light sources and outputs a synthesized illumination light.　

Description

Lighting system and lighting control method

[0001] The present invention relates to a lighting system and a lighting control method.

[0002] To emphasize a specific color of an object, it is possible to add lighting of the corresponding color, but in that case, the corresponding color is added to the entire area illuminated by the lighting. As a result, the color appearance of areas where color appearance should not be changed (e.g., a white background) also changes, resulting in an unnatural appearance. To solve this problem, technologies are being invented that generate lighting that emphasizes or suppresses only a specific color without changing the color temperature of the lighting (e.g., the appearance of white) (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-204707

[0004] The method of Patent Document 1 provides a significantly wider range of adjustment for changes in color appearance. However, it requires multidimensional spectral calculations by pre-setting the colors to be emphasized or suppressed and the direction of change (e.g., changing only saturation while keeping the hue fixed). Furthermore, acquiring spectral data requires expensive equipment such as a spectroradiometer, which creates problems in terms of implementation costs. Therefore, there is a need for a technology that can easily emphasize or suppress specific colors without requiring multidimensional spectral calculations or expensive equipment such as a spectroradiometer.

[0005] In view of the above circumstances, an object of the present invention is to provide a technique that can easily emphasize or suppress a specific color.

[0006] One aspect of the present invention is an illumination system comprising: an illumination light source selection unit that selects a combination of light sources that satisfies a target value for enhancement or suppression of a color to be enhanced or suppressed and that can synthesize a reference illumination light; and an output unit that causes each light source to emit light based on the selected combination of light sources and outputs synthesized illumination light.

[0007] One aspect of the present invention is a lighting control method that selects a combination of light sources that satisfies a target value for enhancing or suppressing a color to be enhanced or suppressed and that can synthesize a reference illumination light, and based on the selected combination of light sources, causes each light source to emit light to output a synthesized illumination light.

[0008] The present invention makes it possible to easily emphasize or suppress a particular color.

[0009] FIG. 1 is a diagram illustrating a configuration example of a lighting device in a first embodiment. FIG. 2 is a diagram illustrating a configuration example of an illumination light information input unit in the first embodiment. FIG. 3 is a diagram for explaining processing performed by the lighting device in the first embodiment. FIG. 4 is a diagram for explaining processing performed by the lighting device in the first embodiment. FIG. 5 is a diagram for explaining processing performed by the lighting device in the first embodiment. FIG. 6 is a diagram for explaining processing performed by the lighting device in the first embodiment. FIG. 7 is a diagram for explaining processing performed by the lighting device in the first embodiment. FIG. 8 is a flowchart showing the flow of processing performed by the lighting device in the first embodiment. FIG. 9 is a diagram illustrating a configuration example of a lighting device in a second embodiment. FIG. 10 is a diagram illustrating a configuration example of a feedback unit in the second embodiment. FIG. 11 is a diagram illustrating a configuration example of a lighting device in a third embodiment. FIG. 12 is a diagram illustrating a configuration example of a feedback unit in the third embodiment. FIG. 13 is a diagram illustrating a configuration example of a lighting device in a fourth embodiment. FIG. 14 is a diagram illustrating a configuration example of a lighting device in a fifth embodiment. FIG. 15 is a diagram illustrating a configuration example of a feedback unit in the fifth embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] The lighting device of the present invention is a device equipped with light sources of multiple colors, each with different central wavelengths and half-widths of its spectral spectrum, i.e., different emission colors. The light sources are, for example, LED (Light Emitting Diode) light sources. The number of light sources for each color is adjusted so that the luminance or brightness (brightness) of each color at maximum emission is somewhat equal. The lighting device is equipped with multiple light sources, and by effectively selecting the light source to be turned on, it easily emphasizes or suppresses a specific color while maintaining the color (e.g., chromaticity value of the white point) of a reference illumination light (hereinafter referred to as "reference illumination light"). Detailed descriptions are provided below based on each embodiment.

[0012] 1 is a diagram showing an example of the configuration of an illumination device 10 according to the first embodiment. The illumination device 10 includes an illumination light information input unit 11, a specified condition input unit 12, an illumination light source selection unit 13, an illumination light source intensity setting unit 14, an illumination light intensity signal correction unit 15, and an output unit 16.

[0013] The illumination light information input unit 11 accepts input of reference illumination light and light from each light source included in the illumination device 10. In the following description, when there is no need to distinguish between the reference illumination light and the light from each light source included in the illumination device 10, they will simply be referred to as illumination light. The illumination light information input unit 11 measures the emission spectrum and color measurement values ​​of each input illumination light. The illumination light information input unit 11 stores information indicating the emission spectrum and color measurement values ​​of each measured illumination light. The color measurement values ​​also include brightness information. The illumination light information input unit 11 outputs the stored information indicating the spectrum of each illumination light and information indicating the color measurement values ​​of each illumination light (the color measurement values ​​of the reference illumination light and the color measurement values ​​of the light from each light source included in the illumination device) to the illumination light source selection unit 13 upon request.

[0014] The specified condition input unit 12 accepts input of a reference illumination light and a target value for emphasizing or suppressing a color to be emphasized or suppressed (hereinafter referred to as a "target color"). Hereinafter, the reference illumination light and the target value for emphasizing or suppressing the target color input to the specified condition input unit 12 are collectively referred to as "specified conditions." The specified condition input unit 12 accepts input of a value indicating which color is to be emphasized or suppressed and to what extent, as a target value for emphasizing or suppressing the target color. Hereinafter, the target value for emphasizing or suppressing the target color is referred to as a color adjustment target value. The specified condition input unit 12 outputs information indicating the accepted reference illumination light, color adjustment target value, and color space to the illumination light source selection unit 13.

[0015] The illumination light source selection unit 13 receives as input the chromaticity values ​​of each illumination light obtained by the illumination light information input unit 11, and information indicating the reference illumination light, color adjustment target value, and color space output from the specified condition input unit 12. Based on the input chromaticity values ​​of each illumination light and the information indicating the reference illumination light, color adjustment target value, and color space, the illumination light source selection unit 13 selects a combination of light sources that satisfies the target value for emphasizing or suppressing the target color and that can synthesize the reference illumination light.

[0016] Here, the combination of light sources selected by the illumination light source selection unit 13 is the combination of light sources used to combine with the reference illumination light. Therefore, in the following description, the combination of light sources selected by the illumination light source selection unit 13 is also referred to as the combination of light sources to be used. The illumination light source selection unit 13 outputs information indicating the combination of light sources to be used, information indicating the chromaticity values ​​(including brightness information) of each light source to be used, and information indicating the chromaticity values ​​(including brightness information) of the reference illumination light to the illumination light source intensity setting unit 14.

[0017] The illumination light source intensity setting unit 14 receives as input the information indicating the combination of light sources to be used output from the illumination light source selection unit 13, information indicating the chromaticity values ​​(including brightness information) of each light source to be used, and information indicating the chromaticity value (including brightness information) of the reference illumination light. The illumination light source intensity setting unit 14 sets the brightness of each light source to be used based on the input information indicating the combination of light sources, the information indicating the chromaticity values ​​(including brightness information) of each light source to be used, and the information indicating the chromaticity value (including brightness information) of the reference illumination light. For example, the illumination light source intensity setting unit 14 calculates the intensity (brightness) of each light source to combine the reference illumination light. The illumination light source intensity setting unit 14 outputs the information indicating the combination of light sources to be used and the information indicating the intensity (brightness) of each light source to the illumination light intensity signal correction unit 15.

[0018] The illumination light intensity signal corrector 15 receives as input information indicating the input / output characteristics related to the brightness of each light source, information indicating the combination of light sources to be used output from the illumination light source intensity setting unit 14, and information indicating the intensity (brightness) of each light source. Here, the information indicating the input / output characteristics related to the brightness of each light source is input from an external device. The information indicating the input / output characteristics related to the brightness of each light source may be only the input / output characteristics related to the brightness of each light source specified by the combination of light sources to be used. Note that the illumination light intensity signal corrector 15 may previously store information indicating the input / output characteristics related to the brightness of each light source included in the illumination device 10.

[0019] The illumination light intensity signal correction unit 15 calculates a signal value for outputting the intensity (brightness) of each light source to be used, based on the input information indicating the input / output characteristics related to the brightness of each light source, the information indicating the combination of light sources to be used, and the information indicating the intensity (brightness) of each light source. For example, the illumination light intensity signal correction unit 15 takes into account the input / output characteristics related to the brightness of each light source to output unit 16 control information for outputting the brightness of each light source found by calculation.

[0020] The output unit 16 includes light sources of a plurality of colors. The output unit 16 receives the control information for each light source output from the illumination light intensity signal correction unit 15. The output unit 16 generates a combined illumination light by causing each light source to emit light based on the received control information for each light source. The output unit 16 outputs the generated combined illumination light.

[0021] 2 is a diagram showing an example of the configuration of the illumination light information input unit 11 in the first embodiment. The illumination light information input unit 11 is composed of an illumination color measurement unit 111 and an illumination light information storage unit 112. The illumination color measurement unit 111 measures the color of each illumination light. Here, each illumination light is the above-mentioned reference illumination light and the light of each light source provided in the lighting device 10. An inexpensive colorimeter can be used as the illumination color measurement unit 111. The illumination light information input unit 11 is composed of an illumination light spectrum measurement unit 113 and a color calculation unit 114.

[0022] The illumination light spectrum measurement unit 113 receives the diffused light when each illumination light is irradiated onto a white board. The illumination light spectrum measurement unit 113 measures the spectrum of the diffused light on the white board for each illumination light, for example, using a colorimeter. Alternatively, the illumination light spectrum measurement unit 113 directly measures the spectrum of each illumination light using an illuminance meter installed in place of a white board. The illumination light spectrum measurement unit 113 stores information indicating the measured spectrum of each illumination light in the illumination light information storage unit 112 and outputs the information to the color calculation unit 114.

[0023] The color calculation unit 114 receives as input information indicating the spectrum of each illumination light measured by the illumination light spectrum measurement unit 113. Based on the received information indicating the spectrum of each illumination light, the color calculation unit 114 converts the tristimulus values ​​obtained by multiplying the spectrum of each illumination light by a color matching function into chromaticity values ​​in a desired color space. In this way, the color calculation unit 114 obtains information indicating the chromaticity values ​​for each illumination light. The color calculation unit 114 stores the obtained information indicating the chromaticity values ​​for each illumination light in the illumination light information storage unit 112.

[0024] The illumination light information storage unit 112 stores information indicating the spectrum of each illumination light measured by the illumination light spectrum measurement unit 113 and information indicating the chromaticity value of each illumination light obtained by the color calculation unit 114 in association with each other. In response to a request from the illumination light source selection unit 13, the illumination light information storage unit 112 outputs the information indicating the spectrum of each illumination light and the information indicating the chromaticity value of each illumination light to the illumination light source selection unit 13.

[0025] As described above, the illumination light information storage unit 112 stores CIE XYZ values ​​and CIE u', v' values ​​calculated based on the XYZ values. Note that the illumination light information storage unit 112 may store CIE L values ​​instead of the XYZ values ​​and u', v' values. ＊ a ＊ b ＊ In addition, the optical spectrum, XYZ values, L ＊ a ＊ b ＊ If the conversion formula from the value is known, the illumination information storage unit 112 may store values ​​in other color spaces. The illumination information storage unit 112 stores only the spectrum or the XYZ values, and the color calculation unit 114 calculates the u', v' values ​​or L values ​​in each subsequent process. ＊ a ＊ b ＊ The value may be calculated.

[0026] The processing performed by the lighting device 10 in the first embodiment will now be described with reference to FIGS. 3 to 8. FIGS. 3 to 8 are diagrams for explaining the processing performed by the lighting device 10 in the first embodiment. In explaining the processing performed by the lighting device 10, the lighting device 10 will be described as having light sources of 11 colors. FIGS. 3 to 8 show the u' and v' values ​​of light sources A to K plotted on a chromaticity diagram. The symbol W on the chromaticity diagram represents the color of the reference white light (reference illumination light). The color W of this reference illumination light corresponds to the appearance of the white color contained in the object, foreground, or background, and its u' and v' values ​​do not change even when the object color is emphasized or suppressed.

[0027] The illumination light information input unit 11 receives input of a reference illumination light and light from 11 light sources. The illumination light information input unit 11 then outputs the chromaticity value W (including brightness information) of the reference illumination light and the chromaticity values ​​A to K (including brightness information) of each light source to the illumination light source selection unit 13. The illumination light source selection unit 13 selects a combination of light sources to be used based on the input chromaticity value W (including brightness information) of the reference illumination light, the chromaticity values ​​A to K (including brightness information) of each light source included in the lighting device 10, the reference illumination light, and information indicating the color adjustment target value and color space.

[0028] First, a case where red color appearance is enhanced or suppressed will be described with reference to Figures 3 and 4. For simplicity, three types of light sources are used. The illumination light source selection unit 13 selects light source C and light source E as light sources that contribute to the appearance of blue and green colors. The illumination light source selection unit 13 then selects one more light source to form a triangle on the chromaticity diagram. Light sources H, I, J, and K form a triangle that includes the reference illumination light color W inside, and this becomes the remaining candidate light source.

[0029] If the use of light source I is taken as the standard state, the illumination light source selection unit 13 can select a light source (light source J or light source K) with a long central wavelength in the spectral spectrum to enhance the appearance of red, and can select light source H with a short central wavelength in the spectral spectrum to suppress the appearance of red, as shown in Fig. 4. Fig. 3 shows an example in which the illumination light source selection unit 13 selected light sources C, E, and J, and Fig. 4 shows an example in which the illumination light source selection unit 13 changed from light source I to light source H and selected light sources C, E, and H.

[0030] 3 , when the illumination light source selection unit 13 selects light sources C, E, and J, the illumination light source selection unit 13 outputs information indicating the combination of light sources C, E, and J to be used, information indicating the chromaticity values ​​(including brightness information) of each of the light sources C, E, and J to be used, and information indicating the chromaticity values ​​(including brightness information) of the reference illumination light to the illumination light source intensity setting unit 14. When the illumination light source selection unit 13 selects light sources C, E, and H as shown in FIG. 4 , the illumination light source selection unit 13 outputs information indicating the combination of light sources C, E, and H to be used, information indicating the chromaticity values ​​(including brightness information) of each of the light sources C, E, and H to be used, and information indicating the chromaticity values ​​(including brightness information) of the reference illumination light to the illumination light source intensity setting unit 14.

[0031] As shown in FIG. 5, the illumination light source selection unit 13 changes the light source E to the light source F when it is desired to emphasize the appearance of green, and changes the light source E to the light source D when it is desired to suppress the appearance of green.

[0032] 6 , blue is only emphasized because there is no candidate light source with a center wavelength shorter than that of light source C. If it is desired to emphasize the appearance of blue, the illumination light source selection unit 13 can simply change light source C to light source A or light source B. Note that when the illumination light source selection unit 13 selects light source A, blue can be suppressed by changing light source A to light source B or light source C.

[0033] As shown in FIG. 7 , if the lighting device 10 includes light sources L, M, and N with lower saturation than the light sources C, E, and J, the lighting source selection unit 13 can suppress a specific color by selecting one of the light sources L, M, and N. For example, if blue needs to be suppressed, the lighting source selection unit 13 can select light source L; if green needs to be suppressed, the lighting source selection unit 13 can select light source M; and if red needs to be suppressed, the lighting source selection unit 13 can select light source N. Even if the lighting device 10 does not include light sources L, M, and N, it is possible to select a virtual light source synthesized using multiple other light sources, such as synthesizing light corresponding to the color of light source L using light sources A and F. In this way, if the lighting device 10 does not include a light source with low saturation, a virtual light source may be selected by synthesizing low-saturation light (e.g., light corresponding to the colors of light sources L, M, and N) using a combination of multiple high-saturation light sources included in the lighting device 10.

[0034] As described above, after the combination of light sources to be used is determined, the illumination light source intensity setting unit 14 determines the brightness of each light source to be used. Specifically, the illumination light source intensity setting unit 14 determines the brightness of each light source to be used in order to realize the chromaticity value W of the reference illumination light. In this case, attention is paid to u' and v' for color tone, and to the Y value for brightness. Here, an example will be described in which only three types of light sources are used. Since only three types of light sources are used in this way, the ratio of u' and v' is uniquely determined. The illumination light source intensity setting unit 14 may determine the Y value of the newly synthesized illumination so that it falls within an allowable error range with respect to the Y value when light sources C, E, and I, which are in a standard state, are used for white brightness.

[0035] After determining the brightness of each light source to be used, the illumination light intensity signal corrector 15 determines the input signal to each light source to be used. If the input and output related to brightness have a nonlinear relationship, the illumination light intensity signal corrector 15 corrects the input signal to a lookup table created from pre-measured data or to an appropriate model function.

[0036] The output unit 16 causes each light source to emit light by inputting the input signal corrected by the illumination light intensity signal corrector 15 to each light source to be used. If color unevenness occurs due to the spatial distribution of the light sources to be used, optical elements such as a diffuser plate and a lens are used to make the color uniform.

[0037] In the above example, a case where three types of light sources are selected has been described, but two types of light sources may also be selected as shown in FIG. 8 . When two types of light sources are used, the light sources are selected so that the color W of the reference illumination is on a line defined by two points on the chromaticity diagram or within an allowable error range from the line. Specifically, as shown in FIG. 8 , if the reference illumination is on a line connecting light source C and light source G, the illumination light source selector 13 selects light source C and light source G, thereby enabling the color of the reference illumination to be synthesized. Note that, if the reference illumination is not on a straight line, such as the line connecting light source C and light source H, the reference value may be determined as the distance between the line connecting light source C and light source H and the position of the reference illumination.

[0038] Furthermore, the number of light sources used to emphasize or suppress a target color may be four or more. In this case, the light sources can be determined by taking into account the spectral shape of the combined illumination light and the color rendering properties.

[0039] Although the explanation is given with the setting condition "the appearance of white color does not change," the reference color that does not change in appearance even when the target color is emphasized or suppressed is not limited to white; for example, instead of "the appearance of white color," it could be "the appearance of the target's skin color."

[0040] FIG. 9 is a flowchart showing the processing flow of the lighting device 10 in the first embodiment. It is assumed that, at the start of the processing shown in FIG. 9 , information about each lighting source (e.g., the spectrum and chromaticity values ​​of each lighting source) is stored in the lighting information input unit 11. The designation condition input unit 12 accepts input of the designation conditions (step S101). The designation condition input unit 12 outputs the input designation conditions to the lighting source selection unit 13. The lighting source selection unit 13 selects a combination of lighting sources to be used based on the information about each lighting source stored in the lighting information input unit 11 and the designation conditions output from the designation condition input unit 12 (step S102). The lighting source selection unit 13 outputs information indicating the selected combination of lighting sources to be used, information indicating the chromaticity values ​​(including brightness information) of each lighting source to be used, and information indicating the chromaticity values ​​(including brightness information) of the reference lighting source to the lighting source intensity setting unit 14.

[0041] The illumination light source intensity setting unit 14 sets the brightness of each light source to be used based on the information output from the illumination light source selection unit 13 (step S103). The illumination light source intensity setting unit 14 outputs information indicating the combination of light sources to be used and information indicating the intensity (brightness) of each light source to the illumination light intensity signal correction unit 15. The illumination light intensity signal correction unit 15 performs correction processing based on the information output from the illumination light source intensity setting unit 14 and information indicating the input / output characteristics related to the brightness of each light source (step S104).

[0042] Specifically, as a correction process, the illumination light intensity signal corrector 15 calculates signal values ​​for outputting the intensities (brightness) of each light source to be used. The illumination light intensity signal corrector 15 outputs control information including the calculated signal values ​​for outputting the intensities (brightness) of each light source to be used to the output unit 16. The output unit 16 causes each light source to emit light based on the control information output from the illumination light intensity signal corrector 15 to generate combined illumination light (step S105).

[0043] The lighting device 10 configured as described above includes the lighting source selector 13 that selects a combination of light sources that satisfies the target value for enhancement or suppression of a target color to be emphasized or suppressed and that can synthesize a reference illumination light, and the output unit 16 that outputs a synthesized illumination light by emitting light from each light source to be used based on the selected combination of light sources. In this way, the lighting device 10 effectively selects the light sources to be turned on. This makes it possible to easily emphasize or suppress a specific color while maintaining the color of the reference illumination light.

[0044] Conventionally, spectral data has been acquired using expensive devices such as spectroradiometers. In contrast, the lighting device 10 uses chromaticity values ​​that can be acquired using inexpensive colorimeters and illuminometers as processing data. Because the chromaticity values ​​are three-dimensional signals, calculation costs can be reduced. Furthermore, the use of inexpensive colorimeters and illuminometers also reduces device costs.

[0045] Second Embodiment In a second embodiment, a configuration that newly includes a feedback function will be described.

[0046] 10 is a diagram showing an example of the configuration of an illumination device 10a according to the second embodiment. The illumination device 10a includes an illumination light information input unit 11, a specified condition input unit 12, an illumination light source selector 13a, an illumination light source intensity setting unit 14, an illumination light intensity signal corrector 15, an output unit 16, a composite illumination light generator 17a, and a feedback unit 18a.

[0047] The illumination device 10a differs in configuration from the illumination device 10 in that it includes an illumination light source selector 13a instead of the illumination light source selector 13, and in that it newly includes a synthetic illumination light generator 17a and a feedback unit 18a. The following description will focus on the differences from the illumination device 10.

[0048] The combined illumination light generation unit 17a receives as input information indicating the combination of light sources to be used and information indicating the intensity (brightness) of each light source, which are output from the illumination light source intensity setting unit 14. Based on the input information indicating the combination of light sources to be used and the information indicating the intensity (brightness) of each light source, the combined illumination light generation unit 17a generates a combined illumination light spectrum, which is the spectrum of illumination light combined using the combination of light sources to be used. The combined illumination light generation unit 17a outputs the information indicating the combination of light sources to be used and the information indicating the intensity (brightness) of each light source to the illumination light intensity signal correction unit 15. The combined illumination light generation unit 17a also outputs the generated combined illumination light spectrum to the feedback unit 18a.

[0049] Feedback unit 18a receives as input information indicating the spectral reflectance of the target color, information indicating the color of the target color under reference illumination light, and the combined illumination light spectrum output from combined illumination light generation unit 17a. Based on the input information indicating the spectral reflectance of the target color, the information indicating the color of the target color under reference illumination light, and the combined illumination light spectrum output from combined illumination light generation unit 17a, feedback unit 18a determines whether the combined illumination light spectrum generated by combined illumination light generation unit 17a satisfies specified conditions by evaluating the amount of change between the color of the combined illumination light and the target color.

[0050] If the feedback unit 18a determines based on the evaluation result that it is necessary to reselect the combination of light sources to be used, it outputs a determination result indicating this to the illumination light source selection unit 13a. The color appearance of an actual object illuminated with the composite illumination light is calculated and evaluated using its spectral reflectance. Furthermore, the evaluation target is not limited to the object illuminated with the composite illumination light, and a color sample such as a color chart may also be used.

[0051] The illumination light source selector 13a performs the same processing as the illumination light source selector 13 in the first embodiment. Furthermore, when it is determined based on the determination result from the feedback unit 18a that it is necessary to reselect a combination of light sources, the illumination light source selector 13a reselects a combination of light sources that satisfies the target value for enhancement or suppression of the target color and that can synthesize reference illumination light.

[0052] 11 is a diagram showing an example of the configuration of the feedback unit 18a in the second embodiment. The feedback unit 18a is composed of a color calculation unit 181, a color difference calculation unit 182, and an accuracy determination unit 183. The color calculation unit 181 receives information indicating the spectral reflectance of the target color and information indicating the combined illumination spectrum output from the combined illumination light generation unit 17a. The color calculation unit 181 calculates tristimulus values ​​by multiplying the input combined illumination spectrum and the spectral reflectance of the target color by color matching functions, and converts the calculation results into colorimetric values. The color calculation unit 181 outputs information indicating the colorimetric values ​​of the combined illumination and information indicating the colorimetric values ​​(simulation values) of the target color to the color difference calculation unit 182.

[0053] Color difference calculation unit 182 receives as input information indicating the colorimetric values ​​(measured values) of the reference illumination light, information indicating the colorimetric values ​​(measured values) of the target color under the reference illumination light, and information indicating the colorimetric values ​​of the combined illumination light and information indicating the colorimetric values ​​of the target color output from color calculation unit 181. Color difference calculation unit 182 calculates the color difference of the target color under the reference illumination light and the combined illumination light based on the input information indicating the colorimetric values ​​of the reference illumination light, the information indicating the colorimetric values ​​of the target color under the reference illumination light, the information indicating the colorimetric values ​​of the combined illumination light, and the information indicating the colorimetric values ​​of the target color. Color difference calculation unit 182 outputs the information indicating the color difference of the target color to accuracy determination unit 183.

[0054] The accuracy determination unit 183 receives as input information indicating the color difference of the target color output from the color difference calculation unit 182. Based on the received information indicating the color difference of the target color, the accuracy determination unit 183 determines whether or not a combination change condition is satisfied. The combination change condition is a condition for causing the illumination light source selection unit 13a to reselect the combination of light sources to be used. For example, the combination change condition is that the color difference of the target color (the amount of color change due to the combined illumination light) is equal to or greater than a threshold. If the combination change condition is satisfied, it means that the specified condition is not satisfied.

[0055] The accuracy determination unit 183 determines that the combination change condition is satisfied when the color difference of the target color indicated by the input information indicating the color difference of the target color is equal to or greater than a threshold. When the combination change condition is satisfied, the accuracy determination unit 183 feeds back the determination result to the illumination light source selection unit 13a. The determination result includes at least an instruction to reselect the combination of light sources to be used. Note that the illumination light source selection unit 13a may also include information indicating how far the color difference of the target color is from the threshold in the determination result.

[0056] If the color difference of the target color indicated by the input information indicating the color difference of the target color is less than the threshold, the accuracy determination unit 183 determines that the combination change condition is not satisfied. If the combination change condition is not satisfied, the accuracy determination unit 183 does not perform any particular process.

[0057] The threshold value is not limited to a constant and may be updated during processing, for example, when searching for a combination of light sources that maximizes the color difference (amount of change).

[0058] As described above, when the illumination light source selection unit 13a receives a judgment result from the feedback unit 18a that includes an instruction to reselect the combination of light sources to be used, the illumination light source selection unit 13a will reselect a combination of light sources that reduces the color difference of the target color, satisfies the target value for emphasizing or suppressing the target color, and can synthesize the reference illumination light.

[0059] The lighting device 10a configured as described above can achieve the same effects as those of the first embodiment. Furthermore, the lighting device 10a evaluates whether the combined illumination light obtained based on the combination of light sources selected by the illumination light source selection unit 13a satisfies the conditions input by the specified condition input unit 12. If the combined illumination light does not satisfy the specified conditions, the lighting device 10a reselects the combination of light sources to be used. This allows the optimal combination of light sources to be selected that satisfies the specified conditions. This makes it possible to easily emphasize or suppress specific colors with greater precision.

[0060] Third Embodiment In the second embodiment, an evaluation is performed based on the spectrum of the combined illumination light obtained based on the combination of light sources to be used to determine whether the combination of light sources to be used satisfies the specified conditions, and the combination of light sources to be used is reselected as necessary. In the third embodiment, unlike the second embodiment, a configuration is described in which feedback is performed based on the combined illumination light actually emitted from the output unit.

[0061] 12 is a diagram showing an example of the configuration of an illumination device 10b according to the third embodiment. The illumination device 10b includes an illumination light information input unit 11, a specified condition input unit 12, an illumination light source selector 13, an illumination light source intensity setting unit 14, an illumination light intensity signal corrector 15b, an output unit 16, and a feedback unit 18b.

[0062] The illumination device 10b differs in configuration from the illumination device 10 in that it includes an illumination light intensity signal correction unit 15b instead of the illumination light intensity signal correction unit 15, and in that it newly includes a feedback unit 18b. The following description will focus on the differences from the illumination device 10.

[0063] The illumination light source intensity setting unit 14 performs the same processing as the illumination light source intensity setting unit 14 in the first embodiment. Furthermore, the illumination light source intensity setting unit 14 calculates, by simulation, the colorimetric values ​​of the combined illumination light obtained by combining the light sources to be used and the colorimetric values ​​of the target color. The illumination light source intensity setting unit 14 outputs the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light and the calculation results (simulation values) of the colorimetric values ​​of the target color to the feedback unit 18b.

[0064] The feedback unit 18b receives as input the combined illumination light output from the output unit 16, the light reflected from the surface of an object having the target color, and the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light and the target color calculated by the illumination light source intensity setting unit 14. The feedback unit 18b determines whether the input combined illumination light satisfies specified conditions by evaluating the amount of change in the color of the combined illumination light and the target color. If at least one of the amount of change in the color of the combined illumination light and the target color exceeds the allowable error, the feedback unit 18b causes the illumination light intensity signal corrector 15b to readjust the intensity (brightness) of each light source used.

[0065] The illumination light intensity signal corrector 15b performs the same processing as the illumination light intensity signal corrector 15 in the first embodiment. Furthermore, the illumination light intensity signal corrector 15b recalculates the signal value for outputting the intensity (brightness) of each light source to be used, based on the determination result output from the feedback unit 18a.

[0066] 13 is a diagram showing an example of the configuration of the feedback unit 18b in the third embodiment. The feedback unit 18b is composed of an illumination light spectrum measurement unit 184 and a color calculation unit 185. The illumination light spectrum measurement unit 184 receives the combined illumination light output from the output unit 16 as input. The illumination light spectrum measurement unit 184 measures the spectrum of the combined illumination light that has been received. Furthermore, the illumination light spectrum measurement unit 184 measures the spectrum of the target color. The illumination light spectrum measurement unit 184 outputs information indicating the measured spectrum of the combined illumination light and information indicating the spectrum of the target color to the color calculation unit 185.

[0067] The color calculation unit 185 receives as input the information indicating the spectrum of the combined illumination light output from the illumination light spectrum measurement unit 184, the information indicating the spectrum of the target color, and the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light and the target color output from the illumination light source intensity setting unit 14. The color calculation unit 185 multiplies the input spectrum of the combined illumination light and the spectrum of the target color by color matching functions to calculate tristimulus values, and converts the calculation results into colorimetric values.

[0068] The color calculation unit 185 calculates the error between the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light calculated by the illumination light source intensity setting unit 14 and the colorimetric values ​​(actual measured values) of the combined illumination light obtained by the above conversion, and calculates the error between the calculation results (simulation values) of the colorimetric values ​​of the target color calculated by the illumination light source intensity setting unit 14 and the colorimetric values ​​(actual measured values) of the target color obtained by the above conversion. If at least one of the calculated errors exceeds an allowable threshold, the color calculation unit 185 feeds back the determination result to the illumination light intensity signal corrector 15b. The determination result includes at least an instruction to readjust the brightness of the light source to be used.

[0069] As described above, when the feedback unit 18b provides a determination result including an instruction to readjust the brightness of the light source to be used, the illumination light intensity signal correction unit 15b adjusts the brightness of the light source to be used so as to reduce the error.

[0070] The lighting device 10b configured as described above can achieve the same effects as those of the first embodiment. Furthermore, the lighting device 10b performs feedback to the illumination light intensity signal corrector 15b based on the synthesized illumination light actually output from the output unit 16. This allows the brightness of the light source to be adjusted as needed. This makes it possible to easily emphasize or suppress specific colors with greater precision.

[0071] Fourth Embodiment In a fourth embodiment, a configuration will be described in which a human subjectively evaluates the synthesized illumination light emitted from the output unit, and corrections are made based on the evaluation results.

[0072] 14 is a diagram showing an example of the configuration of an illumination device 10c according to the fourth embodiment. The illumination device 10c includes an illumination light information input unit 11, a specified condition input unit 12, an illumination light source selector 13c, an illumination light source intensity setting unit 14, an illumination light intensity signal corrector 15, an output unit 16, and a determination unit 19c.

[0073] The illumination device 10c differs in configuration from the illumination device 10 in that it includes an illumination light source selection unit 13c instead of the illumination light source selection unit 13, and in that it newly includes a determination unit 19c. The following description will focus on the differences from the illumination device 10.

[0074] The determination unit 19c receives as input the results of human evaluation. Here, the results of human evaluation refer to the results of human evaluation of the change in the target color and the appearance of colors other than the target color when the synthesized illumination light output from the output unit 16 is irradiated (for example, evaluation that the target color is not emphasized or suppressed, or that a specific color other than the target color is difficult to see, etc.).

[0075] The determination unit 19c determines the amount of correction or the correction policy based on the input evaluation result. For example, if the input evaluation result indicates that a specific color (e.g., blue) is too strong, the determination unit 19c determines the amount of correction or the correction policy for suppressing the specific color as a constraint. The determination unit 19c outputs the determined constraint to the illumination light source selection unit 13c.

[0076] The illumination light source selector 13c performs the same processing as the illumination light source selector 13 in the first embodiment. Furthermore, when a constraint condition is obtained from the determiner 19c, the illumination light source selector 13c selects a combination of light sources that satisfies the target value for emphasizing or suppressing the target color and that can synthesize reference illumination light, taking the obtained constraint condition into consideration. For example, as described above, when a correction amount or correction policy for suppressing a specific color is obtained as a constraint condition, the illumination light source selector 13c uses the light source combination previously selected as a reference and again selects a combination of light sources that suppresses the specific color, satisfies the target value for emphasizing or suppressing the target color, and that can synthesize reference illumination light.

[0077] The lighting device 10c configured as described above can achieve the same effects as the first embodiment. Furthermore, the lighting device 10c reselects the combination of light sources to be used, taking into account the results of human evaluation. In this way, the lighting device 10c can also take into account how actual colors appear. As a result, it becomes possible to easily emphasize or suppress specific colors with greater precision.

[0078] Fifth Embodiment In the fifth embodiment, a configuration in which the second embodiment and the third embodiment are combined will be described.

[0079] 15 is a diagram showing an example of the configuration of an illumination device 10d according to the fifth embodiment. The illumination device 10d includes an illumination light information input unit 11, a specified condition input unit 12, an illumination light source selector 13d, an illumination light source intensity setter 14, an illumination light intensity signal corrector 15d, an output unit 16, a composite illumination light generator 17d, and a feedback unit 18d.

[0080] The illumination device 10d differs from the illumination device 10a in that the illumination device 10d includes an illumination light source selector 13d, an illumination light intensity signal corrector 15d, a composite illumination light generator 17d, and a feedback unit 18d instead of the illumination light source selector 13a, the illumination light intensity signal corrector 15, the composite illumination light generator 17a, and the feedback unit 18a. The following description will focus on the differences from the illumination device 10a.

[0081] The illumination light source selector 13d performs the same processing as the illumination light source selector 13a in the second embodiment.

[0082] The illumination light source intensity setting unit 14 performs the same processing as the illumination light source intensity setting unit 14 in the third embodiment.

[0083] The combined illumination light generation unit 17d performs the same processing as the combined illumination light generation unit 17a in the second embodiment.

[0084] The illumination light intensity signal corrector 15d performs the same processing as the illumination light intensity signal corrector 15 in the second embodiment. Furthermore, the illumination light intensity signal corrector 15d recalculates signal values ​​for outputting the intensity (brightness) of each light source to be used, based on the feedback results from the feedback unit 18d. For example, the illumination light intensity signal corrector 15d takes into account the input / output characteristics related to the brightness of each light source that have been input, and outputs to the output unit 16 control information for outputting the calculated brightness of each light source.

[0085] The feedback unit 18d receives the combined illumination light output from the output unit 16. The feedback unit 18d determines whether the combined illumination light satisfies the specified conditions by evaluating the amount of change between the color of the combined illumination light and the target color. That is, the feedback unit 18d determines whether the combined illumination light satisfies the specified conditions by evaluating the error between the actually output combined illumination light and the target value for the degree of enhancement or suppression of the target color.

[0086] The feedback unit 18d has the functions of both the feedback unit 18a in the second embodiment and the feedback unit 18b in the third embodiment. Therefore, the feedback unit 18d determines whether the combined illumination light spectrum generated by the combined illumination light generation unit 17d satisfies the specified conditions by evaluating the amount of change between the color of the combined illumination light and the target color. Furthermore, the feedback unit 18d determines whether the combined illumination light output from the output unit 16 satisfies the specified conditions by evaluating the amount of change between the color of the combined illumination light and the target color.

[0087] If the feedback unit 18d determines based on the determination result that it is necessary to reselect the combination of light sources to be used, it causes the illumination light source selector 13d to reselect the combination of light sources to be used. Furthermore, if the amount of change in at least one of the color of the combined illumination light and the target color exceeds the allowable error, the feedback unit 18d causes the illumination light intensity signal corrector 15d to re-adjust the intensity (brightness) of each light source to be used.

[0088] 16 is a diagram showing an example of the configuration of a feedback unit 18d in the fifth embodiment. The feedback unit 18d is made up of a color difference calculation unit 182, an accuracy determination unit 183, an illumination light spectrum measurement unit 184, and a color calculation unit 186.

[0089] Color difference calculation unit 182 receives as input information indicating the colorimetric values ​​(measured values) of the reference illumination light, information indicating the colorimetric values ​​(measured values) of the target color under the reference illumination light, and information indicating the colorimetric values ​​of the combined illumination light and the target color output from color calculation unit 186. Color difference calculation unit 182 calculates the color difference between the target color under the reference illumination light and the combined illumination light based on the input information indicating the colorimetric values ​​of the reference illumination light, the information indicating the colorimetric values ​​of the target color under the reference illumination light, the information indicating the colorimetric values ​​of the combined illumination light, and the information indicating the colorimetric values ​​of the target color. Color difference calculation unit 182 outputs the information indicating the color difference to accuracy determination unit 183.

[0090] The accuracy determination unit 183 receives as input the information indicating the color differences output from the color difference calculation unit 182. The accuracy determination unit 183 determines whether the combination change condition is satisfied based on the received information indicating the color differences. If the color difference indicated by the received information indicating the color differences is equal to or greater than a threshold, the accuracy determination unit 183 determines that the combination change condition is satisfied. If the combination change condition is satisfied, the accuracy determination unit 183 instructs the illumination light source selection unit 13d to re-select the combination of light sources to be used. If the color difference indicated by the received information indicating the color differences is less than the threshold, the accuracy determination unit 183 determines that the combination change condition is not satisfied. If the combination change condition is not satisfied, the accuracy determination unit 183 does not perform any particular processing.

[0091] The illumination light spectrum measurement unit 184 receives the combined illumination light output from the output unit 16. The illumination light spectrum measurement unit 184 measures the spectrum of the combined illumination light that it receives. Furthermore, the illumination light spectrum measurement unit 184 measures the spectrum of the target color. The illumination light spectrum measurement unit 184 outputs information indicating the measured spectrum of the combined illumination light and information indicating the spectrum of the target color to the color calculation unit 186.

[0092] Color calculation unit 186 has the functions of color calculation unit 181 in the second embodiment and color calculation unit 185 in the third embodiment. That is, color calculation unit 186 receives as input information indicating the spectral reflectance of the target color, information indicating the combined illumination light spectrum output from combined illumination light generation unit 17 d, information indicating the combined illumination light spectrum output from illumination light spectrum measurement unit 184, information indicating the spectrum of the target color, and the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light and the calculation results (simulation values) of the colorimetric values ​​of the target color output from illumination light source intensity setting unit 14.

[0093] The color calculation unit 186 calculates tristimulus values ​​by multiplying the combined illumination light spectrum output from the combined illumination light generation unit 17 d and the spectral reflectance of the target color by color matching functions, and converts the calculation results into colorimetric values. The color calculation unit 186 outputs information indicating the colorimetric values ​​of the combined illumination light and information indicating the colorimetric values ​​(simulation values) of the target color to the color difference calculation unit 182.

[0094] Furthermore, the color calculation unit 186 receives as input the information indicating the spectrum of the combined illumination light output from the illumination light spectrum measurement unit 184, the information indicating the spectrum of the target color, and the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light and the target color output from the illumination light source intensity setting unit 14. The color calculation unit 186 multiplies each of the input spectrum of the combined illumination light and the spectrum of the target color by color matching functions to calculate tristimulus values ​​and converts the calculation results into colorimetric values.

[0095] Color calculation unit 186 calculates the error between the calculation results (simulation values) of the colorimetric values ​​of the combined illumination light calculated by illumination light source intensity setting unit 14 and the colorimetric values ​​(actual measured values) of the combined illumination light obtained by the above conversion, and calculates the error between the calculation results (simulation values) of the colorimetric values ​​of the target color calculated by illumination light source intensity setting unit 14 and the colorimetric values ​​(actual measured values) of the target color obtained by the above conversion. If at least one of the calculated errors exceeds an allowable threshold, color calculation unit 186 feeds back the determination result to illumination light intensity signal corrector 15d.

[0096] The lighting device 10d configured as described above can achieve the same effects as those of the first embodiment. Furthermore, the lighting device 10d can provide necessary feedback to both the illumination light source selector 13d and the illumination light intensity signal corrector 15d. This makes it possible to easily emphasize or suppress specific colors with greater precision.

[0097] (Modification 1 common to the first to fifth embodiments) The lighting devices 10, 10a, 10b, 10c, and 10d in each of the embodiments may be configured to include at least either the feedback unit 18a in the second embodiment or the feedback unit 18b in the third embodiment, and the determination unit 19c in the fourth embodiment. That is, it is sufficient for each embodiment to include at least either the feedback unit 18a or the feedback unit 18b, and the determination unit 19c.

[0098] (Modification 2 common to the first to fifth embodiments) Some of the functional units included in the lighting devices 10, 10a, 10b, 10c, and 10d in each embodiment may be implemented in one or more other devices. For example, a lighting system may be configured by implementing the output unit 16 as a lighting device and the functional units other than the output unit 16 in another device (e.g., a lighting control device).

[0099] Some or all of the functional units of the lighting devices 10, 10a, 10b, 10c, and 10d are realized as software by a processor such as a central processing unit (CPU) executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, read-only memories (ROMs), and compact disc read-only memories (CD-ROMs), and storage devices such as hard disks built into computer systems.

[0100] Some or all of the functional units of the lighting devices 10, 10a, 10b, 10c, and 10d may be realized using hardware including an electronic circuit (electronic circuit or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0101] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0102] The present invention can be applied to a lighting device having a plurality of light sources.

[0103] DESCRIPTION OF SYMBOLS 10, 10a, 10b, 10c, 10d... Illumination device, 11... Illumination light information input unit, 12... Designated condition input unit, 13, 13a, 13c, 13d... Illumination light source selection unit, 14... Illumination light source intensity setting unit, 15, 15b, 15d... Illumination light intensity signal correction unit, 16... Output unit, 17a, 17d... Synthetic illumination light generation unit, 18, 18a, 18b, 18d... Feedback unit, 19c... Determination unit, 111... Illumination color measurement unit, 112... Illumination light information storage unit, 113... Illumination light spectrum measurement unit, 114... Color calculation unit, 181... Color calculation unit, 182... Color difference calculation unit, 183... Accuracy determination unit, 184... Illumination light spectrum measurement unit, 185... Color calculation unit, 186... Color calculation unit

Claims

1. A lighting system comprising: an illumination light source selection unit that selects a combination of light sources that satisfies the target value for enhancement or suppression of the color to be enhanced or suppressed and that can synthesize reference illumination light; and an output unit that causes each light source to emit light based on the selected combination of light sources, thereby outputting synthesized illumination light.

2. The lighting system according to claim 1, further comprising a feedback unit that readjusts at least one of the combination of light sources or the brightness of each light source used based on the spectrum of the composite illumination light obtained based on the selected combination of light sources or the composite illumination light output from the output unit.

3. The lighting system according to claim 1 or 2, further comprising a judgment unit that determines the amount of correction or correction policy for the illumination light source selection unit based on the results of a human evaluation of the change in the target color when illuminated with the synthetic illumination light output from the output unit and the appearance of colors other than the target color, and the illumination light source selection unit selects the combination of light sources according to the amount of correction or correction policy determined by the judgment unit.

4. A lighting control method comprising: selecting a combination of light sources that satisfies the target value for the enhancement or suppression of the color to be enhanced or suppressed and that can synthesize reference illumination light; and outputting synthesized illumination light by emitting light from each light source to be used based on the selected combination of light sources.

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