JP2005291915A - Method and system for evaluating brightness feeling of space - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluation method and an evaluation system, which can precisely predict an evaluation value of brightness feeling of a space, even for the space in which a region having high brightness exists. <P>SOLUTION: A computation means 11 extracts brightness distribution data in the range of effective visual field, from the brightness distribution data of a selected data file (S7), and calculates the occupation rate R in the brightness range according to the illumination intensity level from the extracted brightness distribution data (S8). The evaluation value B of the brightness feeling is calculated by substituting the occupation rate R in expression (1) (S9), and the calculated evaluation value B of the brightness feeling is displayed in a dialogue box D3 displayed on a screen of a display means 12 (liquid crystal display 3). Even when the region having the high brightness exists in the objective space, by evaluating the brightness feeling of the space according to the ratio of the region except for the region having such high brightness to the total, the evaluation value of the brightness feeling of the space can be precisely predicted, even for the space in which the region having the high brightness exists. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  An object of the present invention is to provide an evaluation method and an evaluation system for evaluating a sense of brightness in space.

  Conventionally, one of evaluation values for evaluating an illumination space is called “a feeling of brightness of space”. A sense of brightness in the space is defined as the impression of the brightness felt for the entire space, unlike “brightness”, which is a psychological quantity perceived for a certain limited visual object. This is a comprehensive evaluation of “brightness” that can be felt for the entire space when the entire space is observed. Expressions related to "brightness" such as "this room is bright" and "this shop is dark" are commonly used expressions when observing the illuminated space. It is an expression of the result of evaluating the brightness of the space. The evaluation of the brightness of the space is directly related to the quality of the target space, so that the space that is felt “dark” is regarded as bad lighting, and is regarded as very important in the lighting design.

  In conventional lighting design, average horizontal illuminance has been widely used as an index for evaluating the brightness of this space. The Japanese Industrial Standard “Illuminance Standard”, which is the only standard related to lighting design, has been established based on illuminance. For example, in an office office space, it is said that the average horizontal illuminance on the desk surface should be 750 lux or more in order to achieve the necessary brightness of the space.

  As shown in FIG. 9, the illuminance is a photometric quantity that captures the amount of light incident on the target X. The observer actually feels "brightness", not the light that is incident on the object, but the light that is incident on the object is incident on the observer's eyes out of the light reflected by the object It is against light. And since the photometric quantity that captures the light incident on the observer's eyes is luminance, the “brightness” of the object is a comprehensive evaluation of the “brightness” of the object and the “brightness” of the entire space. Can be expected to be evaluated based on luminance.

  Here, the correspondence between the average horizontal illuminance and the evaluation value of the brightness of the space, which has been used as an index for evaluating the brightness of the space in the past, was performed for the living room of the house (see FIG. 14). Results obtained by experiments are shown in FIG. 10 (see Non-Patent Document 1). The numerical value on the vertical axis represents an index for sensitivity evaluation, and defines the level of “brightness” that is darker as the numerical value is smaller and brighter as the numerical value is larger. The correlation coefficient between the sense of brightness of the space and the average horizontal illuminance obtained from this experimental result is 0.41, and the correspondence between the two is not good.

  On the other hand, FIG. 11 shows the experimental results for determining the relationship between the average luminance within the viewing angle of 105 × 80 degrees and the evaluation value of the brightness of the space. The correlation coefficient between the sense of brightness of the space and the average luminance obtained from this experimental result is 0.75, which is better than the correspondence with the average horizontal illuminance shown in FIG. It can be said that it shows the effectiveness of feeling evaluation. Further, Non-Patent Document 2 shows from experimental results that there is a high correspondence between the average luminance in the vertical viewing angle range of 40 degrees and the brightness evaluation of the space. It is proposed to evaluate the feeling of brightness. FIG. 12 shows the relationship between the average luminance in the vertical viewing angle range of 40 degrees and the evaluation value of the brightness of the space from the luminance distribution obtained from the result of FIG. 11. The correlation coefficient between the two is 0.79. And the correspondence relationship between the brightness evaluation value of the space and the average horizontal illuminance in FIG.

As described above, it is apparent that it is more appropriate to evaluate the sense of brightness of the space, which is an evaluation regarded as important in illumination design, based on the luminance distribution of the observation visual field rather than the average horizontal plane illuminance. And the method of predicting the brightness feeling evaluation of space using the average brightness | luminance (For example, the average brightness | luminance of the range of 40 degree | times of a vertical viewing angle) in the brightness | luminance distribution of an observer's visual field has been proposed conventionally ( For example, see Patent Document 2).
JP 11-1111019 A Akira Iwai et al .: Brightness in the living room-When downlights are installed-Journal of the Lighting Society of Japan Vol1.83, No.2, pp.81-86 (1999) DLLoe et al .: Apperance of litenvironment and its relevance in lighting design: Experimental study, Lighting Reserach Technology, 26-3, pp.119-133 (1994)

By the way, when the correspondence relationship between the average luminance in the rectangular area M indicated by the broken line in FIG. 14 and the brightness evaluation value of the space is obtained, the result shown in FIG. 13 is obtained. The correlation coefficient between the average luminance in the rectangular area M obtained from this experimental result and the sense of brightness of the space is 0.89, which is a higher value than the experimental results shown in FIG. 11 and FIG. . Thus, the correspondence between the average luminance in the rectangular area M set on the wall of the living room and the sense of brightness of the space is more correlated than the correspondence between the average luminance in the visual field and the average luminance in the range of the vertical viewing angle of 40 degrees. The reason why the number is high is that in the calculation of the average luminance in the rectangular area M, a high value of 1000 [cd / m ² ] or more such as an appliance light-emitting unit and a light source (lighting fixtures such as the ceiling light K1 and downlight K2 in FIG. It is thought that the brightness of the level is not included in the calculation.

Here, as shown in FIG. 15, when the correspondence between the luminance of the appliance light emitting unit and the evaluation value of the brightness of the space is obtained, the influence of the luminance of the appliance light emitting unit on the evaluation value of the brightness of the space is a rectangular region. It was found that it was extremely small compared to the effect of the average luminance in M. However, although the luminance of an object perceived as if it is emitting light, such as an instrument light-emitting unit, has a small effect on the brightness evaluation value of the space as shown in the experimental results of FIG. 15, While the brightness of objects such as walls is about 100 [cd / m ² ], it has a very high level of 1000 [cd / m ² ] or more, and the calculated value of average brightness is large. It has an influence.

Therefore, in order to accurately predict the brightness feeling evaluation value of the space, the high luminance area of 1000 [cd / m ² ] or more is excluded as described above, and the area that affects the brightness feeling of the space is excluded. (For example, the rectangular area M) needs to be extracted, and in the conventional evaluation method using the average luminance, the spatial light is emitted when there is a high luminance area of 1000 [cd / m ² ] or more such as an instrument light emitting unit. The prediction accuracy of the brightness feeling evaluation value was lowered.

By the way, in the example shown in FIG. 14, since the lighting fixtures K1 and K2 are both arranged on the ceiling, there is no high-luminance region in the rectangular region M set on the wall, but the illumination attached to the wall If the appliance is present in the rectangular area M, a high brightness area of 1000 [cd / m ² ] or more may be included, which may make it impossible to predict the brightness evaluation value of the space with high accuracy.

As described above, the conventional evaluation method of calculating the average brightness of a set region in the luminance distribution of the observer's visual field and evaluating the feeling of the brightness of the space has an effect on the evaluation value of the brightness of the space. Although there is a small area, evaluation of the sense of brightness of the space occurs when there is a high-luminance area of 1000 [cd / m ² ] or more, such as an instrument light-emitting part or a light source, which has a great influence on the calculation of the average value. There has been a problem that the prediction accuracy of the value is lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an evaluation method capable of predicting a brightness evaluation value of a space with high accuracy even in a space where a region with high luminance exists. To provide an evaluation system.

  In order to achieve the above object, the invention of claim 1 is an evaluation method for evaluating a feeling of brightness defined as an impression of brightness felt by a person with respect to the entire space, and a visual field in which the space is observed The ratio of the area where the brightness is at a predetermined level to the predetermined visual field range is obtained, and the brightness feeling of the space is evaluated based on the ratio.

  According to the present invention, even when a high brightness area exists in the target space, the brightness of the space is evaluated based on the ratio of the area excluding such a high brightness area to the entire area. It is possible to predict the brightness evaluation value of the space with high accuracy even in a space where a high area exists.

  The invention of claim 2 is characterized in that, in the invention of claim 1, when the average illuminance of the space is 300 lux or less, the predetermined level expressed by luminance is in a range of 20 to 75 candela per square meter. .

  According to the present invention, by determining the luminance range suitable for obtaining the evaluation value of the brightness of the space as a range according to the overall brightness of the space, it is possible to achieve higher accuracy particularly in the lighting space in the house. It is possible to predict the brightness evaluation value of the space.

  The invention of claim 3 is characterized in that, in the invention of claim 1, when the average illuminance of the space is 300 lux or more, the predetermined level expressed by luminance is in a range of 75 to 300 candela per square meter. .

  According to the present invention, by determining the luminance range suitable for obtaining the evaluation value of the brightness of the space as a range according to the overall brightness of the space, it is possible to achieve higher accuracy particularly in the lighting space in the office. It is possible to predict the brightness evaluation value of the space.

  The invention of claim 4 is characterized in that, in the invention of claim 1, 2 or 3, the predetermined visual field range is a range of 60 degrees left and right and 40 degrees above and below the center of the observation visual field.

  According to this invention, the amount of calculation for calculating the evaluation value without reducing accuracy by setting the visual field range for obtaining the evaluation value of the brightness of the space to the size of the visual field called the effective visual field capable of instantaneously accepting information. Can be reduced.

  In order to achieve the above object, the invention of claim 5 is an evaluation system for evaluating a feeling of brightness defined as an impression of brightness that a person feels with respect to the entire space, and a visual field in which the space is observed Measuring means for measuring the luminance distribution within a predetermined visual field range in the computer, calculating means for calculating a ratio of the area where the luminance level is a predetermined level with respect to the visual field range from the luminance distribution, and calculating by the calculating means And display means for displaying an evaluation value obtained by evaluating the brightness of the space at the ratio.

  According to the present invention, even when a high brightness area exists in the target space, the brightness of the space is evaluated based on the ratio of the area excluding such a high brightness area to the entire area. It is possible to predict the brightness evaluation value of the space with high accuracy even in a space where a high area exists.

  According to the present invention, even when a high-luminance area exists in the target space, the brightness of the space is evaluated by evaluating the ratio of the area to the entire area excluding such a high-luminance area. It is possible to provide a space brightness evaluation method and an evaluation system capable of predicting the brightness evaluation value of a space with high accuracy even in a space where a high area exists.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a space brightness feeling evaluation method and an evaluation system thereof according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 4, a hallway in a house where two lighting fixtures 30 are arranged on one wall is used as a lighting space, and a sense of brightness is felt by a plurality of subjects while changing the light amount (luminance) of the lighting fixture 30. When the sensitivity evaluation experiment to evaluate was conducted, the experimental result shown in FIG. 5 and FIG. 6 was obtained. FIG. 6 shows the relationship between the logarithmic value of the average luminance [cd / m ² ] in the visual field at the viewpoint position of the observer and the brightness feeling evaluation value. In addition, the numerical values on the vertical axis in the following graphs including FIG. 5 and FIG. 6 represent the sensitivity evaluation index, and the level of “brightness” is such that the smaller the numerical value, the darker and the brighter the numerical value. It prescribes. In this experimental result, the correlation coefficient between the average luminance in the field of view and the brightness feeling evaluation value was 0.73 ("wall lighting for corridors that achieves both glarelessness and brightness", Ohara (See Kazuki, Journal of the Illuminating Society of Japan, Vol86, No.10, pp.777-781 (2002)).

On the other hand, FIG. 5 shows the ratio (hereinafter referred to as “occupation ratio”) and brightness of the area in the illumination space where the luminance is in the range of ^{20 to} 75 [cd / m ² ] in the entire area in the visual field of the observer. The relationship with the feeling evaluation value is shown. In this experimental result, the correlation coefficient between the occupation ratio of the luminance range in the visual field and the brightness feeling evaluation value was 0.83. Based on the results of these two experiments, the evaluation method of this embodiment evaluates the feeling of brightness using the occupancy ratio in the field of view of the luminance range as compared to the above-described conventional method of evaluating the feeling of brightness using the average luminance. It is obvious that the brightness of the space can be evaluated with higher accuracy. From the experimental results shown in FIG. 5, the correlation between the space brightness evaluation value B and the occupation ratio R according to the evaluation method of the present invention is expressed by the following equation (1).

B = 0.60R + 0.53 (1)
However, the appropriate luminance range for obtaining the brightness feeling evaluation value varies depending on the overall brightness of the target space. That is, in an illumination space in a house, it is usually sufficient that the average illuminance is about 300 lux, but in an office illumination space, an average illuminance of 300 lux or more is necessary. When the same experiment as described above was performed, as shown in FIG. 7, the brightness evaluation value could not be predicted with the occupancy ratio in the region where the luminance was in the range of ^{20 to} 75 [cd / m ² ]. As shown in FIG. 5, it was found that the brightness evaluation value can be predicted with a high accuracy of a correlation coefficient of 0.85 by using the occupancy ratio of the region where the luminance is in the range of 75 to 300 [cd / m ² ]. . Therefore, when the average illuminance of the target space is 300 lux or less, the brightness feeling evaluation value is predicted based on the occupancy ratio of the region that has a luminance range of ^{20 to} 75 [cd / m ² ], and the average illuminance is 300 lux. In the above case, it is desirable to predict the brightness evaluation value based on the occupation ratio of the region in the range of 75 to 300 [cd / m ² ].

  By the way, the range of the human visual field is 200 degrees left and right and 125 degrees above and below the visual angle with the viewpoint as the center, but it takes a considerable amount of calculation man-hours to detect the occupancy by detecting the luminance for the entire visual field range. Become. On the other hand, it has been found that the size of a visual field called an effective visual field that can accept information instantaneously is in the range of 60 degrees left and right and 40 degrees up and down with a visual angle centered on the viewpoint (“VDT”). And visual characteristics ", Toyohiko Hatada, Ergonomics, 22-2, pp.45-52 (1986)), usually when a person observes the space, it is instantly" bright "or" dark "and" brightness of the space " Therefore, if the brightness of the space is evaluated within the above effective field of view (60 degrees left and right, 40 degrees above and below the viewing angle, the accuracy will be reduced). It is possible to predict the evaluation value efficiently by reducing the calculation man-hours.

  FIG. 2 shows the hardware configuration of the evaluation system according to the present embodiment, which includes a CCD camera 1 that captures an illumination space to be evaluated, and a computer device 2. The CCD camera 1 is a conventionally well-known device that uses a CCD (charge coupled device) as an image sensor, and captures still image (raster image) data (hereinafter referred to as “image data”) via a cable 4. Output to the computer device 2. The computer apparatus 2 is a so-called notebook type in which a CPU, a motherboard, a memory, a hard disk, a keyboard, a pointing device, and the like are built in a main body 2a, and a liquid crystal display 3 is attached to the main body 2a so as to be freely opened and closed. The software (program) for implementing the evaluation method in the form is installed. The image data output from the CCD camera 1 via the cable 4 is taken into the computer apparatus 2 via a general-purpose interface (for example, USB, IEEE 1394, etc.) provided as a standard in the computer apparatus 2.

  FIG. 3 shows a block diagram of the evaluation system in the present embodiment. The measuring means 10 for measuring the luminance distribution within a predetermined visual field range (the effective visual field range) in the visual field observing the space, and the luminance distribution Further, calculation means 11 for calculating a ratio (occupancy ratio) of a region where the luminance level becomes a predetermined level with respect to the visual field range, and display means for displaying the occupation ratio calculated by the calculation means 11 as an evaluation value of the brightness of the space. 12. Here, the measuring means 10 is realized by controlling the hardware of the computer apparatus 2 with the above-mentioned software executed by the CPU of the computer apparatus 2, and the CCD camera 1 and the computer apparatus 2, the calculating means 11 and the display means 12 are realized.

  Next, the brightness evaluation method of this embodiment, that is, the operation of the evaluation system of this embodiment will be described in detail with reference to the flowchart of FIG.

  First, an image (image data) obtained by capturing the space (illumination space) to be measured by the measuring means 10 with the CCD camera 1 is taken into the computer device 2 and acquired (S1), and each pixel value of the acquired image data is converted into luminance. The brightness distribution data is created by conversion (S2), and the created brightness distribution data is stored in a data file (S3). Note that it is confirmed with the operator whether or not the brightness distribution data of another space is to be created (S4), and if so, the processes of S1 to S3 are repeated.

  When the creation of the luminance distribution data by the measuring means 10 is completed, a dialog box D1 for inputting the name of the data file for calculating the brightness feeling evaluation value is displayed on the screen of the liquid crystal display 3, and the operator uses the keyboard of the computer device 2. When a data file is selected using a pointing device or a pointing device (S5), when a data file is selected, an input of an illuminance level is awaited (S6). Here, the illuminance level is obtained by measuring the average illuminance in the target illumination space using an illuminometer, and the dialog box D2 displayed on the screen of the liquid crystal display 3 by the operator using a keyboard or pointing device. To enter.

The computing means 11 extracts the luminance distribution data within the effective visual field range from the luminance distribution data of the selected data file (S7), and the luminance range corresponding to the illuminance level (that is, the illuminance level is determined from the extracted luminance distribution data). brightness when following 300 lux in the range of 20~75 [cd / m ^2], the brightness when the illumination level is above 300 lux calculates the occupation rate R range) of 75~300 [cd / m ^2] At the same time (S8), the brightness R evaluation value B is calculated by substituting the occupancy rate R into the above equation (1) (S9), and the calculated brightness evaluation value B is displayed on the display means 12, that is, the liquid crystal display 3. Is displayed in the dialog box D3 displayed on the screen (S10). Note that the operator confirms whether or not the brightness evaluation value of another illumination space is to be calculated (S11). If so, the processes of S5 to S11 are repeated. If not, the process ends.

  As described above, according to the evaluation method and the evaluation system of the present embodiment, even when a high-luminance region exists in the target space, the space excluding such a high-luminance region depends on the ratio of the entire region. By evaluating the feeling of brightness, it is possible to predict the brightness feeling evaluation value of the space with high accuracy even in a space where a region with high luminance exists. Moreover, if the evaluation system of this embodiment is used, a brightness feeling evaluation value can be obtained immediately after the measurement of the luminance distribution, and the brightness feeling of the target space is achieved with respect to the designed lighting space. It can be verified immediately on site.

  In this embodiment, the luminance distribution data within the effective visual field range is created from the luminance distribution data. However, if the field angle of the lens 1a of the CCD camera 1 is matched with the effective visual field range, the luminance distribution data is effective. There is an advantage that the processing time (S7 in FIG. 1) for extracting the luminance distribution data within the visual field range is not required and the calculation time can be shortened.

  By the way, in the present embodiment, luminance is used to obtain a sense of brightness. However, the brightness may be converted into “brightness” scaled so as to be adapted to human senses, and obtained by the “brightness”. Good. As such “brightness”, brightness BR represented by the following formula (2) (see “The brightness of objects in non-uniform luminance fields”, T. Takeuchi, Proceeding of CIE 22rd Session (1995)) And brightness calculation formulas ("Brightness Perception of Visual Objects with Uniform Background-Study on Brightness Perception Considering Luminance Contrast", Shigeki Nakamura et al., Illumination Society, 88-2, pp.77-84 (See 2004)) can be used.

BR = 1.2 (Lo ^0.4 -3ΔLmin ^0.7 ) (2)
However, Lo is the luminance [cd / m ² ] of the visual target, and ΔLmin is the luminance difference discrimination threshold [cd / m ² ].

It is a flowchart explaining embodiment of the brightness feeling evaluation method and evaluation system which concern on this invention. It is a system block diagram same as the above. It is a block diagram same as the above. It is a perspective view of the illumination space (corridor of a house) which conducted the experiment same as the above. It is a graph which shows an experimental result same as the above. It is a graph which shows the experimental result of the conventional method. It is a graph when the average illuminance is high and the luminance range is low, showing the experimental results. It is a graph in the case where average illuminance and a brightness | luminance range are high, showing an experimental result same as the above. It is explanatory drawing of a feeling of brightness. It is a graph which shows the experimental result of the conventional method. It is a graph which shows the experimental result of another conventional method. It is a graph which shows the experimental result of other conventional methods. It is a graph which shows another experimental result. It is a perspective view which shows the living room of the house which conducted the experiment. It is a graph which shows the experimental result of the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CCD camera 2 Computer apparatus 3 Liquid crystal display 10 Measuring means 11 Calculation means 12 Display means

Claims (5)

  An evaluation method for evaluating a feeling of brightness defined as an impression of brightness felt by a person over the entire space, wherein the brightness is at a predetermined level with respect to a predetermined visual field range in the visual field observing the space A method for evaluating a feeling of brightness in a space, characterized in that a ratio occupied by an area is obtained and the feeling of brightness in the space is evaluated based on the ratio.   2. The method for evaluating a feeling of brightness of a space according to claim 1, wherein when the average illuminance of the space is 300 lux or less, the predetermined level expressed by luminance is in a range of 20 to 75 candela per square meter.   2. The method for evaluating a feeling of brightness of a space according to claim 1, wherein when the average illuminance of the space is 300 lux or more, the predetermined level expressed by luminance is in a range of 75 to 300 candela per square meter.   4. The method for evaluating a feeling of brightness of a space according to claim 1, wherein the predetermined visual field range is a range of 60 degrees left and right and 40 degrees up and down from the center of the observation visual field.   An evaluation system for evaluating a sense of brightness defined as an impression of brightness perceived by a person with respect to the entire space, measuring means for measuring a luminance distribution within a predetermined visual field range in a visual field observing the space; A calculation means for calculating a ratio of a region where the luminance level is a predetermined level with respect to the visual field range based on the luminance distribution, and an evaluation value for evaluating a sense of brightness of the space at the ratio calculated by the calculation means. A space brightness evaluation system comprising display means for displaying.

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