JP2014063656A - Lighting control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a light environment in a space by using a simple optical measurement method and incorporating how humans sense brightness, thereby realizing energy saving while also maintaining comfort.SOLUTION: A lighting control system 1 comprises a plurality of luminaires 2 installed in a room space X having an opening A through which daylight is able to enter, an illuminance sensor 3 for measuring illuminance, and a control device 4 capable of changing the brightness of the luminaires 2. The control device 4 includes: image generation means 10 for generating a predicted luminance image in which a luminance state in the room space X is predicted on the basis of the illuminance obtained from the illuminance sensor 3; image conversion means 20 for converting the predicted luminance image to an image to be evaluated having luminance contrast and human adaptation added thereto; determination means 30 for determining using the image to be evaluated whether the lighting state of the room space X is appropriate or not; and illumination adjustment means for changing the brightness of the luminaires 2 when the lighting state is determined to be inappropriate by the determination means 30.

Description

  The present invention relates to a lighting control system that controls the brightness of a lighting device provided in a room space.

  Considering power crises and resource depletion, there is a need to reduce power consumption in houses. Therefore, in the case of reducing the power consumption in the lighting equipment among the equipment consuming electric power provided in the house, safety, convenience and comfort are greatly impaired if the lighting is simply eliminated. Also, simply replacing the light source often results in a dark and uncomfortable space depending on the characteristics of the light source.

  Therefore, technology that achieves energy saving by controlling lighting without impairing human comfort is important. For example, Patent Literature 1 and Patent Literature 2 disclose a technique for controlling illumination based on a detection result by a human sensor or an illuminance sensor.

JP-A-8-17239 JP-A-10-64383

  By the way, for example, when using daylight and using only artificial lighting, the adaptation of human eyes is different, so people often feel different brightness even at the same illuminance. . In view of this, when artificial lighting is controlled based on the illuminance of the illuminance sensor as in the above-mentioned patent document, it often feels dark and uncomfortable when daylight is used. For this reason, it is necessary to evaluate a comfortable light environment based not only on illuminance but also on luminance, which is light entering the human eye. On the other hand, in order to measure the luminance, for example, it is necessary to photograph the viewing environment with an expensive luminance camera, and there is a problem that the cost is increased only by the measurement. In addition, a predetermined measurement time is required to perform measurement in a range that matches human sensitivity, and measurement is difficult under daylight that changes with time.

  Therefore, the present invention solves such problems of the prior art, and uses a simple light measurement method, and controls the light environment of the space after taking in how to sense human brightness. Thus, an object of the present invention is to provide a lighting control system capable of realizing energy saving while maintaining comfort.

  In order to solve the above problems, an illumination control system according to the present invention includes a plurality of illumination devices provided in a room space having an opening through which daylight can enter, an illuminance sensor that measures the illuminance of the room space, and illumination. A control device capable of changing the brightness of the device, and the control device generates a predicted luminance image in which the luminance state of the room space is predicted based on the illuminance obtained from the illuminance sensor, and the predicted luminance Image conversion means for converting an image into an evaluated image that takes luminance contrast and human adaptation into account, determination means for determining whether the lighting condition of the room space is appropriate using the evaluated image, and appropriateness by the determination means Lighting adjustment means for changing the brightness of at least one of the plurality of lighting devices when it is determined that the lighting device is not.

  In the present invention, a luminance image is generated based on information from the illuminance sensor, and the brightness of the room space is evaluated based on the luminance image. In this way, by setting the luminance image as an evaluation target, it is possible to evaluate the brightness of the space where daylight and artificial lighting that cannot be evaluated in the illuminance image based on the illuminance are mixed. Moreover, since it is the structure which calculates a brightness | luminance image by calculation based on the information from an illumination sensor, an expensive brightness | luminance sensor is not required and the prediction brightness | luminance image used as the foundation of evaluation object can be produced | generated immediately.

  Then, by converting the predicted luminance image into an image to be evaluated in consideration of luminance contrast and human adaptation, it is possible to perform an evaluation close to the sense that a person existing in the room space evaluates the brightness of the room space. By adjusting the brightness of the room space based on this evaluation, it is possible to adjust the lighting close to the human sense.

  As described above, the lighting control system uses a simple light measurement method and incorporates the way people perceive brightness to control the light environment in the space, thereby saving energy while maintaining comfort. Can be realized.

  The image generation means is a basic luminance image generation means for generating a luminance image of a room space from a predetermined position as a basic luminance image in a state where the illuminance of each lighting device and the illuminance of daylight from the opening are set to one, Conversion coefficient deriving means for deriving a conversion coefficient for converting the basic luminance image based on information from the illuminance sensor, predicted luminance image generating means for generating a predicted luminance image by multiplying the basic luminance image by the conversion coefficient, It is preferable to comprise. In this case, the conversion coefficient is immediately determined by the conversion coefficient deriving means based on the information from the illuminance sensor. A predicted luminance image can be easily generated using the conversion coefficient and a basic luminance image generated in advance, and the predicted luminance image can be generated quickly (in real time).

  The conversion coefficient deriving means compares the first luminance image obtained by changing only the illuminance condition with the imaging state of the basic luminance image and the basic luminance image, and changes in the luminance of the first luminance image with respect to the basic luminance image. Are obtained by changing only the illuminance condition and the first luminance image is obtained by changing the illuminance condition. A second coefficient obtained by comparing different second luminance images and basic luminance images, comparing the amount of change in luminance of the second luminance image with respect to the basic luminance image for each same coordinate, and accumulating the results of the comparison. An illuminance / luminance conversion coefficient indicating a relationship between illuminance and luminance with respect to a basic luminance image obtained based on the first coefficient and the second coefficient, and a linear function including an illuminance / luminance conversion coefficient and using information from the illuminance sensor as a variable, , And calculate the linear function Deriving the transform coefficients in the illuminance by inputting the information from the sensor, it is preferable. In this case, the first coefficient is obtained by comparing the first luminance image and the basic luminance image, and the second coefficient is obtained by comparing the second luminance image and the basic luminance image. By indicating the relationship between the first coefficient and the second coefficient as a linear function with illuminance as a variable, the luminance at the illuminance other than the illuminance at the time of the first luminance image and the illuminance at the time of the second luminance image. A coefficient (that is, a conversion coefficient) that may be obtained by comparing the image with the basic luminance image can be derived. Then, by multiplying the basic luminance image by this conversion coefficient, a predicted luminance image at the illuminance can be immediately generated. As a result, based on the illuminance information obtained from the illuminance sensor, a predicted luminance image at the illuminance can be generated.

  The image conversion means includes a brightness image conversion means for converting a luminance image into a brightness image, and the brightness image conversion means outputs a predicted brightness image obtained by performing brightness image conversion on the predicted brightness image as an evaluated image. It is preferable to derive. Since the brightness image is an image that takes into account brightness contrast and human adaptation in the room space, the brightness of the room space can be evaluated in a state closer to a human sense by converting to a brightness image. .

  The determining means is a histogram generating means for generating a histogram of the predicted brightness image, a condition determining means for determining whether or not the histogram satisfies a preset condition, and the condition determining means determines that the condition is not satisfied. Processing means for processing the predicted brightness image into a processed brightness image satisfying the condition, a re-converting means for re-converting the processed brightness image into a luminance image and creating a processed luminance image, and the processed luminance image And a difference calculation unit that compares the predicted luminance image and calculates a luminance difference for each coordinate in the processed luminance image and the predicted luminance image, and the illumination adjustment unit adjusts the brightness of each lighting device so as to eliminate the difference. It is preferable to change.

  The histogram of the image makes it easy to grasp the brightness tendency over the entire image. For this reason, it is easy to define the brightness condition setting that is considered to be good on the histogram from the brightness image. Therefore, the present invention pays attention to such a point, forms a histogram of the predicted brightness image, and sets in advance a condition setting that is favorable on the histogram. Then, it is possible to easily evaluate the brightness of the room space by determining whether or not a histogram of the image is satisfied with respect to the condition. If the condition is not satisfied, a processed brightness image that satisfies the condition is created from the predicted brightness image, and the created processed brightness image is reconverted to generate a processed brightness image. Then, by comparing the generated processed luminance image with the predicted luminance image, the position and output of the lighting device to be controlled can be calculated backward.

  The condition judging means is a kurtosis calculating means for calculating the kurtosis of the histogram of the predicted brightness image, and whether or not the condition is satisfied on the condition that the calculated kurtosis is larger than a preset threshold value. It is preferable to include first condition determining means for determining In this case, by setting conditions using the kurtosis for the histogram, it is possible to easily grasp the tendency of the histogram and whether or not the condition is satisfied, and the processing becomes simple.

  The condition determining means includes a threshold setting means for setting two threshold values, an upper threshold value and a lower threshold value, with respect to the histogram of the predicted brightness image, a ratio of the predicted brightness image below the lower threshold value, and an upper threshold value. A ratio calculating means for calculating the above ratio, and a second for determining whether or not the condition is satisfied on the condition that the ratio below the lower threshold and the ratio above the upper threshold are greater than a preset ratio It is preferable to comprise the condition judging means. In this case, by setting conditions using the ratio below the lower threshold and the ratio above the upper threshold for the histogram, it is easy to grasp the trend of the histogram and whether or not the condition is satisfied. Can be processed easily.

  According to the present invention, energy saving can be realized while maintaining comfort by expressing brightness perceived by a person and controlling the light environment while using a simple light measurement method.

It is a figure showing the whole lighting control system composition concerning an embodiment. It is a figure which shows a luminance image. It is the figure which plotted the luminance value of the basic luminance image and the comparative luminance image for every pixel. It is a figure for calculating | requiring the linear function showing the relationship between illumination intensity and a conversion coefficient. It is a figure which shows the histogram of an estimated brightness image. It is a figure which shows the example of the process performed in a process means. It is a flowchart which shows the flow of the brightness control processing of the illuminating device performed in a control apparatus.

  Hereinafter, embodiments of an illumination control system according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the illumination control system 1 controls the brightness of a room space X. An opening A to which a window or the like is attached is provided in the room space X, and daylight can enter the room space X from the opening A. By providing the opening A, the amount of daylight incident on the room space X changes with time, and the brightness of the room space X changes.

  The illumination control system 1 includes a plurality of illumination devices 2, an illuminance sensor 3, and a control device 4. The plurality of lighting devices 2 are respectively provided in the room space X and illuminate the room space X. The illuminance sensor 3 is provided at a predetermined position in the room space X and detects the illuminance of light received by the light receiving surface. In the present embodiment, it is provided at any position on the wall surface (vertical surface) of the room space X. Although FIG. 1 shows an example in which one illuminance sensor 3 is provided in the room space X, a plurality of illuminance sensors 3 may be provided in the room space X. The control device 4 can individually change the brightness of the plurality of lighting devices 2.

  The control device 4 is functionally configured to include an image generation unit 10, an image conversion unit 20, a determination unit 30, an illumination adjustment unit 40, and an illumination on / off detection unit 50.

  The image generation unit 10 generates a predicted luminance image in which the luminance state of the room space X is predicted based on the illuminance obtained from the illuminance sensor 3. For this reason, the image generation means 10 includes a basic luminance image generation means 11, a conversion coefficient derivation means 12, and a predicted luminance image generation means 13.

  The basic luminance image generation means 11 is a state in which the luminance image of the room space X when viewed from a predetermined position with the illuminance of each lighting device 2 and the illuminance of daylight from the opening A set to one is the basic luminance. Generate as an image. As this basic luminance image, a luminance image obtained by actually imaging the room space X using the imaging apparatus 100 can be used. In addition, it is also possible to calculate a basic luminance image by simulation. In this case, the basic luminance image generation means 11 inputs the floor plan of the room space X, the position of the opening A, and the installation position of the lighting device 2 in this case. It is calculated using data such as. As a method for calculating a luminance image by simulation, for example, an existing method such as Radiance or inspirer can be used. The basic luminance image generated here is generally a range that can be seen by a person's line of sight or viewpoint that can occur in a living life. An example of the basic luminance image is shown in FIG. In FIG. 2A, an opening A, a desk, a shelf, and the like of the room space X are shown. In addition, a luminance is associated with each pixel of the basic luminance image.

  The basic luminance image generation unit 11 generates a first luminance image, a second luminance image, and a third luminance image that are used by the conversion coefficient deriving unit 12 to derive the conversion coefficient. The first luminance image is obtained by changing only the illuminance condition from the imaging state of the basic luminance image. That is, the first luminance image and the basic luminance image have the same range. The first luminance image has different illuminance conditions from the second luminance image and the third luminance image. Note that the first luminance image can be calculated by simulation or generated by actually capturing an image using the imaging device 100, as in the case of the basic luminance image. The second luminance image is obtained by changing only the illuminance condition from the imaging state of the basic luminance image. Further, the second luminance image has different illuminance conditions from the first luminance image and the third luminance image. The third luminance image is obtained by changing only the illuminance condition from the imaging state of the basic luminance image. Also, the third luminance image has different illuminance conditions from the first luminance image and the second luminance image. Similar to the first luminance image, the second luminance image and the third luminance image can be calculated by simulation or can be generated by actually capturing an image using the imaging device 100. FIG. 2B shows an example of the first luminance image, FIG. 2C shows an example of the second luminance image, and FIG. 2D shows an example of the third luminance image. In FIG. 2 (a) to FIG. 2 (d), for the sake of convenience, the difference in luminance is represented by line type.

  The basic luminance image generation unit 11 acquires the illuminance of the room space X corresponding to the generated first luminance image to third luminance image. The illuminance can be calculated by simulation, or the illuminance obtained from the illuminance sensor 3 when the first to third luminance images are captured by the imaging device 100 can be used. When the illuminance is calculated by simulation, the basic luminance image generation unit 11 uses a general equation (for example, E = (F × N × U × M) / A [lx]: F used for obtaining the illuminance). Can be used as the luminous flux of the illumination device 2, N is the number of illumination devices 2, U is the illumination rate, M is the maintenance rate, and A is the floor area. The basic luminance image generation unit 11 can also calculate the illuminance by using an existing method such as Radiance or inspirer.

  The conversion coefficient deriving unit 12 derives a conversion coefficient for converting the basic luminance image generated by the basic luminance image generating unit 11 based on the information from the lighting device 2. More specifically, the conversion coefficient deriving unit 12 first compares the first luminance image and the basic luminance image as the condition 1, and sets the change amount of the luminance of the first luminance image with respect to the basic luminance image to the same coordinate ( Compare every pixel). Specifically, for example, the luminance of the pixel at the coordinate Z of the basic luminance image shown in FIG. 2A is compared with the luminance of the pixel at the coordinate Z of the first luminance image shown in FIG. Then, as shown in FIG. 3, the luminance value for each pixel is plotted on the map with the horizontal axis as the luminance value of the basic luminance image and the vertical axis as the luminance value of the first luminance image as the comparative luminance image (see FIG. 3). 3).

  Then, the conversion coefficient deriving unit 12 obtains a straight line L1 representing the plotted result based on the result of plotting the luminance value by comparing the first luminance image and the basic luminance image. In the example shown in FIG. 3, when the vertical axis is the y-axis and the horizontal axis is the x-axis, the straight line L1 is represented by y = 1.5151x. Further, the conversion coefficient deriving unit 12 obtains the slope (1.5151) of the straight line L1 as the first coefficient. Then, the conversion coefficient deriving unit 12 associates the obtained first coefficient with the illuminance corresponding to the first luminance image. Here, it is assumed that the illuminance corresponding to the first luminance image is 14 lux [lx].

  Similarly, as the condition 2, the conversion coefficient deriving unit 12 compares the second luminance image and the basic luminance image, and sets the amount of change in the luminance of the second luminance image with respect to the basic luminance image for each same coordinate (pixel). Compare. Then, the luminance values for each pixel are plotted (square marks in FIG. 3) on the map shown in FIG.

  Then, the conversion coefficient deriving unit 12 obtains a straight line L2 representing the plotted result based on the result of plotting the luminance value by comparing the second luminance image and the basic luminance image. In the example illustrated in FIG. 3, the straight line L2 is represented by y = 2.0748x. Further, the conversion coefficient deriving unit 12 obtains the slope (2.0748) of the straight line L2 as the second coefficient. Then, the conversion coefficient deriving unit 12 associates the obtained second coefficient with the illuminance corresponding to the second luminance image. Here, it is assumed that the illuminance corresponding to the second luminance image is 20 lux [lx].

  Similarly, as the condition 3, the conversion coefficient deriving unit 12 compares the third luminance image and the basic luminance image and sets the amount of change in the luminance of the third luminance image with respect to the basic luminance image for each same coordinate (pixel). Compare. Then, the luminance value for each pixel is plotted (triangle mark in FIG. 3) on the map shown in FIG.

  Then, the conversion coefficient deriving unit 12 obtains a straight line L3 representing the plotted result based on the result of plotting the luminance value by comparing the third luminance image and the basic luminance image. In the example illustrated in FIG. 3, the straight line L3 is represented by y = 3.5067x. Further, the conversion coefficient deriving unit 12 obtains the slope (3.5067) of the straight line L3 as the third coefficient. Then, the conversion coefficient deriving unit 12 associates the obtained third coefficient with the illuminance corresponding to the third luminance image. Here, it is assumed that the illuminance corresponding to the third luminance image is 32 lux [lx].

  Next, the conversion coefficient deriving unit 12 obtains an illuminance / luminance conversion coefficient indicating a relationship between illuminance and luminance with respect to the basic luminance image obtained based on the first coefficient to the third coefficient. Specifically, as shown in FIG. 4, on the map, the horizontal axis represents illuminance (illuminance corresponding to the first luminance image to the third luminance image), and the vertical axis represents the conversion coefficient (first coefficient to third coefficient). The first coefficient to the third coefficient are plotted. And the straight line L10 showing the change of each plotted point is calculated | required. In the example shown in FIG. 4, when the vertical axis is the y-axis and the horizontal axis is the x-axis, the straight line L10 is represented by y = 0.107x, which is a linear function for obtaining the conversion coefficient. The slope (0.107) of the straight line L10 is an illuminance / luminance conversion coefficient indicating the relationship between the illuminance and the luminance with respect to the basic luminance image obtained based on the first coefficient to the third coefficient.

  Further, the conversion coefficient deriving unit 12 obtains a conversion coefficient from the illuminance measured by the illuminance sensor 3 using the obtained linear function. By using the linear function, the conversion coefficient can be obtained from the illuminance value other than the illuminance associated with the first coefficient to the third coefficient. Here, the conversion coefficient can predict the luminance image at the illuminance corresponding to the conversion coefficient by multiplying the basic luminance image by the conversion coefficient.

  The predicted luminance image generation unit 13 generates a predicted luminance image by multiplying the basic luminance image by the conversion coefficient. That is, by using the basic luminance image generated by the basic luminance image generating unit 11 and the conversion coefficient obtained by the conversion coefficient deriving unit 12, the luminance image at the illuminance (( (Hereinafter referred to as “predicted luminance image”). In order to generate the predicted luminance image, only the basic luminance image, the linear function representing the straight line L10 used for deriving the conversion coefficient, and the illuminance value measured by the illuminance sensor 3 need only be present. Therefore, after obtaining the linear function, the first to third luminance images, the first coefficient to the third coefficient, and the like used when obtaining the linear function are not necessary. In this way, a predicted luminance image in the current room space X can be generated based on the illuminance measured by the illuminance sensor 3.

  The image conversion means 20 converts the predicted brightness image generated by the predicted brightness image generation means 13 into an evaluated image that takes brightness contrast and human adaptation into consideration. In the present embodiment, a “brightness image” representing how human light is perceived is used as the image to be evaluated. This brightness image is described in, for example, the known Japanese Patent Application Laid-Open No. 2009-284276.

  Specifically, the image conversion unit 20 includes a brightness image conversion unit 21 that converts a luminance image into a brightness image. The brightness image conversion means 21 performs brightness image conversion on the predicted brightness image generated by the predicted brightness image generation means 13 to derive a predicted brightness image.

  The determination unit 30 determines whether the illumination state of the room space X is appropriate using the predicted brightness image derived by the brightness image conversion unit 21. More specifically, the determination unit 30 includes a histogram creation unit 31, a condition determination unit 32, a processing unit 33, a reconversion unit 34, and a difference calculation unit 35.

  The histogram creation unit 31 creates a histogram of the predicted brightness image converted by the brightness image conversion unit 21. A histogram of the predicted brightness image is shown in FIG. In FIG. 5, the horizontal axis represents the brightness scale value of the brightness image, and the vertical axis represents the distribution amount.

  The condition determining unit 32 determines whether or not the histogram created by the histogram creating unit 31 satisfies a preset condition. That is, it is determined whether or not the brightness of the room space X is appropriate. Therefore, the condition determination unit 32 includes a kurtosis calculation unit 301, a first condition determination unit 302, a threshold setting unit 311, a ratio calculation unit 312, a second condition determination unit 313, and a brightness suitability determination. And means 320.

  The kurtosis calculating unit 301 calculates the kurtosis of the histogram of the predicted brightness image created by the histogram creating unit 31. The first condition determination unit 302 determines whether or not the kurtosis calculated by the kurtosis calculation unit 301 satisfies a preset condition. Here, in the room space X in the present embodiment, it is assumed that the person existing in the room space X feels that the brightness of the room space X is appropriate as the histogram of the brightness image is closer to the normal distribution. In this case, the first condition determination unit 302 determines that the preset condition is satisfied when the kurtosis of the histogram is greater than a preset threshold and is close to a normal distribution. Note that the shape of the histogram that the person in the room space X feels as having appropriate brightness varies depending on the floor plan of the room space X, the size of the opening A, and the like. For this reason, the shape (kurtosis range) of the histogram that feels appropriate brightness is obtained in advance, for example, by analyzing a histogram of a brightness image when a person actually feels appropriate brightness.

  The threshold setting unit 311 sets two thresholds, an upper threshold and a lower threshold, for the histogram of the predicted brightness image created by the histogram creating unit 31. The ratio calculation unit 312 calculates a ratio that is lower than the lower threshold and a ratio that is higher than the upper threshold in the histogram of the predicted brightness image. The second condition determining unit 313 determines whether or not the ratio below the lower threshold calculated by the ratio calculating unit 312 and the ratio above the upper threshold satisfy a preset condition. In the room space X in the present embodiment, as shown in FIG. 5, the ratio of the brightness scale value of 5 or less (lower threshold) is 10% or less, and the ratio of the brightness scale value of 7.5 or more (upper threshold) is In the case of 10% or less, it is assumed that the person existing in the room space X feels that the brightness of the room space X is appropriate. In this case, the second condition determining unit 313 has a histogram of the predicted brightness image in which the ratio of the brightness scale value is 5 or less (lower threshold) is 10% or less, and the brightness scale value is 7.5 or more (upper threshold). ) Is 10% or less, it is determined that a preset condition is satisfied. Note that the distribution state of the histogram that the person in the room space X feels as having appropriate brightness varies depending on the layout of the room space X, the size of the opening A, the color of the wall and ceiling, and the like. For this reason, the distribution of the histogram that feels appropriate brightness is obtained in advance, for example, by analyzing the histogram distribution of the brightness image when the person actually feels appropriate brightness.

  The brightness suitability determination means 320 is the one in which the brightness of the room space X is appropriate when the first condition determination means 302 and the second condition determination means 313 determine that the preset condition is satisfied. Judge as. When it is determined that either one of the first condition determination unit 302 and the second condition determination unit 313 does not satisfy the condition, the brightness suitability determination unit 320 has an inappropriate brightness of the room space X. Judge as a thing.

  When the brightness appropriateness determination means 320 determines that the brightness of the room space X is inappropriate, the processing means 33 is preset with the predicted brightness image derived by the brightness image conversion means 21. Processed into a processed brightness image that satisfies the conditions.

  Hereinafter, a specific example of the processing performed in the processing means 33 will be described. As an example, like the histogram of the predicted brightness image indicated by the solid line in FIG. 6A, the kurtosis of the histogram is small (the peak of the histogram is flat), and the conditions set in advance by the first condition determining unit 302 are as follows. A case where it is determined that the condition is not satisfied will be described. In this case, the processing means 33 processes the predicted brightness image so that the histogram is close to the shape of the normal distribution indicated by the broken line in FIG. 6A, and creates a processed brightness image.

  As another example, as in the histogram of the predicted brightness image indicated by the solid line in FIG. 6B, the brightness scale value at the median value of the histogram is 5 or less, and the brightness scale value is 5 or less (below A case will be described in which the condition that the ratio of (threshold) is 10% or less and the condition that the brightness scale value is 7.5 or more (upper threshold) is 10% or less is not satisfied. In this case, as shown by a broken line in FIG. 6B, the processing unit 33 further reduces the brightness scale value to 5 or less (lower threshold value) so that the brightness scale value at the median value of the histogram is 6.25. ) Is processed so that the ratio of 10) or less and the ratio of the brightness scale value of 7.5 or more (upper threshold) is 10% or less, and a processed brightness image is created.

  Furthermore, as another example, as in the histogram of the predicted brightness image indicated by the solid line in FIG. 6C, there are two histogram peaks, and the ratio of the brightness scale value of 5 or less (lower threshold) is 10 The case where the ratio of the brightness scale value of 7.5 or more (upper threshold) does not satisfy the conditions of 10% or less will be described. In this case, as shown by a broken line in FIG. 6C, the processing unit 33 further sets the brightness scale value to 5 or less so that the median value of the two peaks of the histogram approaches the brightness scale 6.25, respectively. The predicted brightness image is processed so that the ratio of (lower threshold) is 10% or less and the ratio of brightness scale value is 7.5 or more (upper threshold) is 10% or less to create a processed brightness image To do.

  Further, the processing means 33 may consider glare when creating the processed brightness image.

  Here, due to the brightness of the room space X, the color of the walls and ceiling, etc., the predicted luminance image and the predicted brightness image should be brighter or darker no matter how much the lighting device 2 is dimmed. There may be coordinates that cannot. Therefore, the upper and lower threshold values of the histogram are set, and the lighting device 2 is no longer used for the image area corresponding to the portion where the histogram is equal to or higher than the upper threshold and the image region corresponding to the portion where the histogram is equal to or lower than the lower threshold. However, while it is recognized that the brightness of the area cannot be adjusted, the brightness of the area of the image corresponding to the portion of the histogram that is larger than the lower threshold and lower than the upper threshold is adjusted by dimming. You can recognize that you can. Accordingly, it is possible to prevent the process from being performed for the region where the brightness cannot be adjusted. That is, the pixel constituting the portion below the lower threshold and the portion above the upper threshold in the histogram can be excluded from processing by the processing means 33.

  The re-converting unit 34 re-converts the processed brightness image created by the processing unit 33 into a luminance image to create a processed luminance image. The difference calculating unit 35 compares the processed luminance image created by the re-converting unit 34 with the predicted luminance image generated by the predicted luminance image generating unit 13, and compares the luminance for each coordinate in the processed luminance image and the predicted luminance image. Calculate the difference. That is, the difference between the brightness of the current room space X and the brightness of the room space X, which is appropriate brightness, is calculated.

  The illumination adjustment unit 40 changes the brightness of the plurality of illumination devices 2 so as to eliminate the difference in luminance calculated by the difference calculation unit 35. That is, the illumination adjustment unit 40 changes the brightness of at least one of the plurality of illumination devices 2 so that the room space X has an appropriate brightness. Thereby, the brightness of the room space X can be made into appropriate brightness.

  The illumination on / off detection means 50 detects the on state or the off state of the switch of the illumination device 2.

  Here, the control device 4 is an information processing device such as a personal computer, and its hardware configuration is a basic configuration of a normal information processing device, that is, an input device such as a CPU, RAM, ROM, keyboard or mouse, external A communication device that communicates with the storage device, a storage device that stores information, an output device such as a display, and the like are provided as necessary. When these components operate, the functions of the image generation unit 10, the image conversion unit 20, the determination unit 30, the illumination adjustment unit 40, and the illumination on / off detection unit 50 are exhibited.

  Next, the flow of brightness control processing of the illumination device 2 performed in the control device 4 will be described with reference to FIG. Prior to the brightness control process of the lighting device 2, the basic luminance image is generated in the basic luminance image generating unit 11 in the image generating unit 10 as described above, and the linear function (FIG. 4) is generated in the conversion coefficient deriving unit 12. It is assumed that a function representing a straight line L10 is obtained. The brightness control process of the illumination device 2 is started when, for example, the illumination on / off detection unit 50 detects that the switch of the illumination device 2 is turned on.

  First, the illuminance sensor 3 measures the illuminance of the room space X (step S101). The conversion coefficient deriving unit 12 derives a conversion coefficient based on the illuminance measured by the illuminance sensor 3 and the linear function. Then, the predicted luminance image generating unit 13 generates a predicted luminance image by multiplying the conversion coefficient derived by the conversion coefficient deriving unit 12 and the basic luminance image generated by the basic luminance image generating unit 11 (step S102). ).

  Next, the brightness image converting means 21 converts the predicted brightness image generated by the predicted brightness image generating means 13 into a predicted brightness image (step S103). The histogram creation means 31 creates a histogram of the predicted brightness image converted by the brightness image conversion means 21 (step S104). Then, the first condition determination unit 302 determines whether or not the kurtosis of the histogram satisfies a preset condition (step S105).

  When the kurtosis satisfies the preset condition (step S105: YES), the second condition determination unit 313 satisfies the condition that the ratio below the lower threshold and the ratio above the upper threshold satisfy the preset conditions. Whether or not (step S106). When the ratio of the histogram satisfies a preset condition (step S106: YES), the brightness suitability determination unit 320 determines that the brightness of the room space X is appropriate (step S107).

  Next, the illumination on / off detection means 50 determines whether or not the switch of the illumination device 2 has been operated to an off state (extinguishment). When operated in the off state, the brightness control process of the lighting device 2 is terminated. On the other hand, when the switch of the illumination device 2 is not in the OFF state, the process returns to the above-described step S101 and the illuminance sensor 3 performs illuminance measurement.

  When the kurtosis does not satisfy a preset condition (step S105: NO), or when the ratio of the histogram does not satisfy a preset condition (step S106: NO), the brightness suitability determination unit 320 determines that the brightness of the room space X is inappropriate (step S109).

  When the brightness suitability determination unit 320 determines that the brightness of the room space X is inappropriate, the processing unit 33 is preset with the predicted brightness image derived by the brightness image conversion unit 21. A processed brightness image that satisfies the conditions is processed (step S110). Next, the reconverting unit 34 reconverts the processed brightness image created by the processing unit 33 into a luminance image to create a processed luminance image (step S111). Then, the difference calculating unit 35 compares the processed luminance image created by the re-converting unit 34 with the predicted luminance image generated by the predicted luminance image generating unit 13, and compares the processed luminance image for each coordinate in the processed luminance image and the predicted luminance image. A difference in luminance is calculated (step S112).

  Next, the illumination adjustment unit 40 changes the brightness of the plurality of illumination devices 2 so as to eliminate the difference in luminance calculated by the difference calculation unit 35 (step S113). After changing the brightness of the illuminating device 2 in the illumination adjusting means 40, the process returns to the above-described step S101, and the illuminance sensor 3 measures the illuminance.

  The present embodiment is configured as described above, and a luminance image is generated based on information from the illuminance sensor 3, and the brightness of the room space is evaluated based on the luminance image. In this way, it is possible to evaluate the brightness of the space in which daylight and artificial lighting are mixed, which cannot be evaluated with an illuminance image based on illuminance. Moreover, since it is the structure which calculates a brightness | luminance image by calculation based on the information from the illumination intensity sensor 3, an expensive brightness | luminance sensor is not required and the prediction brightness | luminance image used as the basis of evaluation object can be produced | generated immediately. .

  Then, by converting the predicted luminance image into a predicted brightness image that takes luminance contrast and human adaptation into account, a person existing in the room space X performs an evaluation close to the sense of evaluating the brightness of the room space X. be able to. By adjusting the brightness of the room space X based on this evaluation, it is possible to adjust the lighting device 2 close to a human sense. The illuminance is measured at a predetermined interval, for example, every hour or every 30 minutes.

  As described above, the lighting control system 1 maintains comfort by using a simple light measurement method and controlling the light environment of the room space X after taking in how to sense the brightness of a person. Energy saving can be realized.

  Further, based on the illuminance measured by the illuminance sensor 3, the conversion coefficient is derived immediately by the conversion coefficient deriving means 12. A predicted luminance image can be easily generated using the conversion coefficient and a basic luminance image generated in advance, and the predicted luminance image can be generated quickly (in real time).

  The conversion coefficient deriving unit 12 obtains the first to third coefficients described above, and calculates a linear function based on the first to third coefficients. By using this linear function, the conversion coefficient can be easily derived from the illuminance measured by the illuminance sensor 3. Then, by multiplying the basic luminance image by this conversion coefficient, a predicted luminance image at the illuminance can be immediately generated.

  The brightness image conversion means 21 converts the predicted brightness image into a predicted brightness image. The determination unit 30 determines whether or not the lighting state of the room space X is appropriate based on the predicted brightness image. The predicted brightness image is an image that takes into account the brightness contrast and the adaptation of the person in the room space X. Therefore, by converting the predicted brightness image into the predicted brightness image, the predicted brightness image of the room space X can be approximated to a human sense. Brightness can be evaluated.

  The histogram of the predicted brightness image makes it easy to grasp the brightness trend over the entire image. For this reason, it is easy to define the condition setting of the brightness that is favorable on the histogram from the predicted brightness image. Therefore, the histogram creation unit 31 forms a histogram of the predicted brightness image. Then, the condition determining means 32 determines whether or not the histogram of the predicted brightness image is satisfied with respect to a preset condition that is favorable on the histogram, whereby the brightness of the room space X is determined. Can be easily evaluated. If the condition is not satisfied, a processed brightness image that satisfies the condition is created from the predicted brightness image, and the created processed brightness image is reconverted to generate a processed brightness image. Then, by comparing the generated processed luminance image and the predicted luminance image, the position and output of the lighting device 2 to be controlled can be calculated backward.

  The condition determining unit 32 includes a kurtosis calculating unit 301 that calculates the kurtosis of the histogram of the predicted brightness image, and a first condition determining unit that determines whether or not the calculated kurtosis is greater than a preset threshold value. 302. In this way, by setting conditions for the histogram using the kurtosis, it is possible to easily grasp the tendency of the histogram and whether or not the condition is satisfied, and the processing becomes simple.

  In addition, the condition determination unit 32 determines whether or not the ratio of the lower threshold value and the ratio of the upper threshold value or more are larger than a preset ratio with respect to the histogram of the predicted brightness image. Is provided. In this way, by setting conditions using the ratio below the lower threshold and the ratio above the upper threshold with respect to the histogram, it is possible to easily grasp the tendency of the histogram and whether or not the condition is satisfied. Can be processed easily.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the embodiment, an example in which a brightness image is used as an evaluation image in which brightness contrast and human adaptation are taken into account has been described. However, any object other than the brightness image may be used as long as it represents how human brightness is perceived. An evaluation image may be used.

  Moreover, in order to obtain the linear function shown in FIG. 4, the transform coefficient deriving unit 12 obtains the straight line L10 using the first coefficient to the third coefficient, but at least one of the first coefficient to the third coefficient. The straight line L10 may be obtained based on two coefficients, or the straight line L10 may be obtained based on four or more coefficients.

  A plurality of illuminance sensors 3 may be provided. In this case, the average value of these illuminance sensors 3 can be used as the illuminance of the room space X.

  DESCRIPTION OF SYMBOLS 1 ... Lighting control system, 2 ... Lighting apparatus, 3 ... Illuminance sensor, 4 ... Control apparatus, 10 ... Image generation means, 11 ... Basic brightness image generation means, 12 ... Conversion coefficient derivation means, 13 ... Predictive brightness image generation means, DESCRIPTION OF SYMBOLS 20 ... Image conversion means, 21 ... Brightness image conversion means, 30 ... Determination means, 31 ... Histogram preparation means, 32 ... Condition determination means, 33 ... Processing means, 34 ... Re-conversion means, 35 ... Difference calculation means, 40 ... Illumination adjustment means, 301 ... kurtosis calculation means, 302 ... first condition determination means, 311 ... threshold setting means, 312 ... ratio calculation means, 313 ... second condition determination means, A ... opening, X ... room space .

Claims (7)

A plurality of lighting devices provided in a room space having an opening through which daylight can enter;
An illuminance sensor for measuring the illuminance of the room space;
A control device capable of changing the brightness of the lighting device,
The control device includes:
Image generating means for generating a predicted luminance image in which the luminance state of the room space is predicted based on the illuminance obtained from the illuminance sensor;
Image conversion means for converting the predicted luminance image into an image to be evaluated in consideration of luminance contrast and human adaptation;
Determination means for determining whether the lighting state of the room space is appropriate using the evaluated image;
An illumination adjustment unit that changes the brightness of at least one of the plurality of illumination devices when the determination unit determines that it is not appropriate;
A lighting control system. The image generating means includes
Basic luminance image generation means for generating a luminance image of the room space from a predetermined position as a basic luminance image in a state where the illuminance of each lighting device and the illuminance of daylight from the opening are set to one,
Conversion coefficient deriving means for deriving a conversion coefficient for converting the basic luminance image based on information from the illuminance sensor;
Predicted luminance image generation means for generating the predicted luminance image by multiplying the basic luminance image by the conversion coefficient;
The lighting control system according to claim 1, comprising: The conversion coefficient derivation means includes
The imaging state of the basic luminance image is a comparison between the first luminance image obtained by changing only the illuminance condition and the basic luminance image, and the amount of change in luminance of the first luminance image with respect to the basic luminance image is the same. A first coefficient obtained by comparing each coordinate and accumulating the results of the comparison;
The imaging state of the basic luminance image is obtained by changing only the illuminance condition, and the second luminance image having a different illuminance condition from the first luminance image is compared with the basic luminance image, and the basic luminance image A second coefficient obtained by comparing the amount of change in luminance of the second luminance image for each same coordinate and accumulating the results of the comparison;
An illuminance / luminance conversion coefficient indicating a relationship between illuminance and luminance with respect to the basic luminance image obtained based on the first coefficient and the second coefficient;
A linear function including the illuminance / luminance conversion coefficient and using information from the illuminance sensor as a variable; and
Deriving the conversion coefficient at the illuminance by inputting information from the illuminance sensor to the linear function,
The lighting control system according to claim 2. The image conversion means includes
A brightness image converting means for converting the brightness image into a brightness image;
The brightness image conversion means derives a predicted brightness image obtained by performing brightness image conversion on the predicted brightness image as the evaluated image.
The illumination control system according to any one of claims 1 to 3. The determination means includes
A histogram creating means for creating a histogram of the predicted brightness image;
Condition judging means for judging whether or not the histogram satisfies a preset condition;
Processing means for processing the predicted brightness image into a processed brightness image that satisfies the condition when the condition determination means determines that the condition is not satisfied;
Re-converting means for re-converting the processed brightness image into a brightness image to create a processed brightness image;
A difference calculating unit that compares the processed luminance image and the predicted luminance image, and calculates a luminance difference for each coordinate in the processed luminance image and the predicted luminance image;
With
The illumination adjustment means changes the brightness of each illumination device so as to eliminate the difference.
The lighting control system according to claim 4. The condition determining means includes
Kurtosis calculating means for calculating the kurtosis of the histogram of the predicted brightness image;
First condition determining means for determining whether or not the calculated kurtosis satisfies the condition, based on whether or not the calculated kurtosis is greater than a preset threshold;
The lighting control system according to claim 5, comprising: The condition determining means includes
Threshold setting means for setting two threshold values, an upper threshold value and a lower threshold value, for the histogram of the predicted brightness image;
Of the histogram of the predicted brightness image, a ratio below the lower threshold, and a ratio calculation means for calculating a ratio above the upper threshold;
A second condition determining means for determining whether or not the condition is satisfied based on whether the ratio equal to or lower than the lower threshold and the ratio equal to or higher than the upper threshold is greater than a preset ratio;
The lighting control system according to claim 5, comprising:

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