JP2009238410A - Illumination system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately control light by surely detecting a human being from image data, in an illumination system which controls light based on the image data outputted from an image sensor. <P>SOLUTION: An illumination system 10 comprises a light source 12, a lighting circuit 13 for lighting the light source 12, an image sensor 14, and a control part 15 which acquires image data outputted from the image sensor 14 and generates a light control signal for the lighting circuit 13 by image-processing the image data. The control part 15 turns on the light source 12 at such light control rate as an object to be detected can be discriminated on the acquired image data. Thus, neither pyroelectric element nor infrared light source is required for detecting the human being. By surely detecting the human being from the image data, light is controlled accurately. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination system that performs dimming control based on image data output from an image sensor.

  2. Description of the Related Art Conventionally, lighting fixtures that control brightness by measuring the brightness of an irradiation surface with a brightness sensor are known. FIG. 6 shows a luminaire having a photodiode as a brightness sensor. The lighting fixture 51 is provided with a photodiode 52 whose output current changes according to the brightness, and the desk top surface is set as a light condensing range of the photodiode 52. The lighting fixture keeps the illuminance on the desk surface constant even under the influence of external light or other lighting fixtures by controlling the dimming rate of the lighting so that the output of the photodiode becomes constant.

  There is also known a lighting fixture that detects a person with a human sensor and controls turning on and off. FIG. 7 shows a lighting apparatus having a pyroelectric element as a human sensor. The luminaire 61 is provided with a pyroelectric element 62 that senses changes in heat rays, and turns on when a person is detected within a predetermined detection range by the pyroelectric element 62, or turns off when a person is not detected for a certain period of time. To do.

  Further, although not shown, the brightness of the desk top surface is controlled to be constant by controlling the output of the photodiode to be constant when a person is detected by the pyroelectric element by combining the photodiode and the pyroelectric element. Lighting fixtures are also known.

  However, since the pyroelectric element detects the movement of the heat ray, it can be detected when a person is moving, but cannot be detected when a person is seated or stopped. In view of this, there is known an illumination system that detects a person using an image sensor and controls lighting. FIGS. 8A and 8B show an image processing example in which a human body is detected from an image captured by an image sensor in such a system. FIG. 8A shows the case of stationary human body detection. In this case, a difference is calculated by comparing the current image with a previously captured reference image, a difference image is formed, and the presence of a stationary person is detected when there is a certain difference or more in the difference image. FIG. 8B shows a case of motion human body detection for detecting a moving person. In this case, images such as frames 1 to 4 are taken at regular intervals, and a moving person is detected from the difference between the image of frame 2 and the immediately preceding frame 1. The same applies to the difference between the images of the frames 3 and 2 and the difference between the images of the frames 4 and 3.

  There is also known an illumination system that controls lighting by measuring brightness using an image sensor. FIG. 9 shows an example of image information photographed by an image sensor composed of a CCD. Image information photographed by the CCD is formed from dots, and each dot has brightness information. The brightness is measured by calculating the average brightness of all the dots in the range specified as the measurement range in the image information captured by the CCD.

  However, in a system for detecting a person using an image sensor, an image to be captured becomes completely dark when the imaging range becomes dark. Even if such image data is subjected to image processing, a person cannot be identified, so that the person cannot be detected and accurate lighting control cannot be performed.

  For this reason, in the state which turned off illumination, the illuminating device which detects a person using a pyroelectric element is known (for example, refer patent document 1). However, such an apparatus requires a pyroelectric element separately from the image sensor, which increases the cost.

Further, there is known an illumination device that detects a person by irradiating infrared rays and photographing reflected light with an image sensor (CCD) when the illumination is turned off (see, for example, Patent Document 2). However, in such a device, an infrared light source for irradiating infrared rays is required, the infrared light source must be turned on with the illumination turned off, and an image sensor capable of photographing the infrared region is used. Since it is necessary to use, it becomes expensive.
JP 2002-246189 A Japanese translation of PCT publication No. 2004-50196

  The present invention solves the above problem, and in a lighting system that performs dimming control based on image data output from an image sensor, when performing dimming control by detecting a person, the person is reliably detected from the image data. It is an object of the present invention to make it possible to perform dimming control accurately.

  In order to achieve the above-mentioned object, the invention according to claim 1 acquires a light source, a lighting circuit for lighting the light source, an image sensor, and image data output from the image sensor, and converts the image data into an image. A control unit that generates a dimming control signal for the lighting circuit by processing, wherein the control unit is configured to control the light source at a dimming rate capable of identifying the detected object on the acquired image data. Is to light up.

  According to a second aspect of the present invention, in the illumination system according to the first aspect, the image sensor is of a plug-in type, and includes a storage unit that stores information referred to by the control unit, and the storage unit The light control rate that can identify the detected object on the image data acquired by the control unit is stored.

  According to the first aspect of the present invention, since the light source is turned on at a dimming rate capable of identifying the detected object on the image data, a pyroelectric element, an infrared light source, or the like is provided in addition to the image sensor in order to detect a person. Therefore, it is possible to accurately detect the person from the image data and accurately control the light control.

  According to the second aspect of the present invention, the image sensor is of a plug-in type that can be replaced, and the dimming rate capable of identifying the detected object on the image data can be stored in advance in the storage unit of the image sensor. Therefore, the dimming rate can be easily set by replacing the image sensor.

  Hereinafter, an illumination system according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows functional blocks of a lighting system 10 (hereinafter referred to as the present system) of the present embodiment. The system 10 acquires a light source 12, a lighting circuit 13 that lights the light source 12, an image sensor 14, and image data output from the image sensor 14, and performs image processing on the image data to thereby apply the lighting circuit 13 to the lighting circuit 13. And a control unit 15 that generates a dimming control signal. The light source 12, the lighting circuit 13, and the control unit 15 constitute a general lighting fixture.

  The light source 12 is an illumination load composed of an incandescent bulb, a fluorescent lamp, an LED, and the like that are lit by a power source such as the AC power source 11 and capable of current control. The lighting circuit 13 controls the current (load current) flowing through the light source 12. The control of the load current is, for example, phase control or amplitude control. The image sensor 14 is composed of a CCD, a CMOS, or the like. The field of view of the image sensor 14 is determined by the lens 14L, and the field of view is photographed and image data is output. The control unit 15 includes a CPU and the like, acquires image data output from the image sensor 14, and performs image processing on the image data to generate a dimming control signal such as a PWM (Pulse Width Modulation) signal.

  FIG. 2 shows the relationship between the dimming control signal and the current (load current) supplied to the light source 12 (illumination load) in the system 10 configured as described above. The lighting circuit 13 controls the load current of the light source 12 according to the on-duty of the PWM signal generated by the control unit 15. The larger the on-duty of the PWM signal, the larger the load current of the light source 12 and the higher the dimming rate.

  The system 10 can be set to one of three types regarding whether or not a person is detected and whether or not brightness is measured. The first type is an operation type in which the control unit 15 detects a person by identifying a human body on the image data, and changes the dimming rate of the light source 12 in accordance with the detection of the person (in the present specification, this is an operation type). N type). The second type is an operation type in which the control unit 15 measures brightness from image data and changes the dimming rate according to the brightness measurement value (this is referred to as “A type” in this specification). The third type is an operation type (in this specification, this is referred to as AN type) in which the control unit 15 changes the dimming rate by combining human detection and brightness measurement values. Hereinafter, each of these operation types will be described.

  First, the N type will be described. The control unit 15 detects a person by, for example, stationary human body detection or moving human body detection by image processing (see, for example, FIGS. 8A and 8B). Prior to the start of use of this system, the relationship between the light control rate of the light source 12 and the possibility of human body detection is obtained, and the light control rate is set. For example, when the dimming rate is 9% or less and human body detection is not possible, and the dimming rate of 10% is the minimum dimming rate that human body detection is possible, the dimming rate when a person is detected is specified as the specification of this system. Is set to 10% or more (for example, 70%) set by the user, and the dimming rate when no person is detected is set to 10%.

  In the dimming control operation of this system, the control unit 15 turns on the light source 12 at a dimming rate of 70% when a person is detected, and at a dimming rate of 10% when no person is detected. Turn on the light source.

  Thereby, this system 10 can ensure the minimum brightness required for the human body detection by the image sensor 14. Note that the brightness may be further increased by external light or another light source, but it is not darkened, and external light or the like does not hinder human body detection.

  Here, countermeasures against deterioration with time of the light source 12 will be described with reference to FIGS. FIG. 3A shows a change in the luminous flux with time with respect to the cumulative lighting time of the light source 12. In general, the light source 12 deteriorates as the cumulative lighting time increases, and the luminous flux decreases. FIG. 3B shows a setting example of the dimming rate with respect to the cumulative lighting time. For example, the dimming rate when a person is detected still has room for increase (up to 100%) when the initial value set in advance preparation is 70%. Even when the luminous flux of the light source 12 at the same dimming rate decreases as the cumulative lighting time increases, the brightness when a person is detected can be controlled to be constant regardless of the cumulative lighting time by increasing the dimming rate. Can do. The light control rate when no person is detected is 10% at which the initial value is 10% to ensure the minimum brightness necessary for human detection by the image sensor 14, and the light source 12 at the same light control rate as the cumulative lighting time increases. Even if the luminous flux decreases, the minimum brightness required for human body detection can be ensured by increasing the dimming rate.

  Next, the A type will be described. The control unit 15 measures the brightness from the image data and controls the dimming rate of the light source 12 so that the measured brightness becomes a preset brightness target value. Since the human body is not detected in the A type, the light source 12 may be turned off when the external light becomes bright.

  FIG. 4 shows an A type dimming rate setting method performed prior to use of the present system. For example, 750 [lx] of the desk surface illuminance is set as the target brightness value. The illuminance is measured by an illuminance meter 17 placed on the desk surface while raising or lowering the dimming rate of the light source 12 in the absence of external light. The total output value is stored in the lighting system 10. The brightness measurement by the image sensor 14 may be an average value as well as a total value of RGB output, or a value converted to brightness suitable for visibility using conversion from RGB to Y. May be.

  In the dimming control operation of this system, the control unit 15 increases the dimming rate by 1% when the total RGB output value of the image sensor 14 is lower than the value stored in advance preparation. Performs feedback control that decreases by%.

  Thereby, the illumination system 10 can maintain the desk surface illuminance at a target value, for example, 750 [lx] even when external light enters.

  Next, the AN type will be described. When detecting a person, the control unit 15 performs the same dimming control as that of the A type, and keeps the desk surface illuminance at the target value. When no person is detected, lighting to brighten the desk surface is not necessary for the person, but the dimming rate of the light source 12 is fed back so that the human body can be detected from the output of the image sensor 14. Control.

  Prior to the start of use of this system, the average value of RGB of all dots of the image sensor 14 at the minimum brightness that allows human detection can be obtained from the output of the image sensor 14. For example, if the average value of RGB of all dots of the image sensor 14 is less than 10, human body detection cannot be performed, and if human body detection is possible at 10, the average value of RGB at the minimum brightness at which human body detection is possible is 10. . As a specification of the system, when no person is detected, the dimming rate is reduced by 0.1% when the average RGB value of all dots of the image sensor 14 exceeds 10, and the dimming rate is 0 when the average value is less than 10. .Control to increase 1%. Thereby, the light source 12 can be dimmed and controlled at the minimum dimming rate necessary for human body detection, which is energy saving.

  As described above, the system 10 turns on the light source 12 at a dimming rate capable of identifying the detected object on the image data. Therefore, a pyroelectric element, an infrared light source, or the like is provided in addition to the image sensor 14 to detect a person. Therefore, it is possible to accurately detect the person from the image data and accurately control the light control.

  Next, an illumination system according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows functional blocks of the illumination system 20 (hereinafter referred to as the present system) of the present embodiment. The system 20 includes a plug-in type image sensor 24 that can be replaced with respect to a lighting fixture 21 including a light source 12, a lighting circuit 13, and a control unit 15. The image sensor 24 includes a storage unit 25 that stores information referred to by the control unit 15. The storage unit 25 stores a dimming rate that can identify the detected object on the image data acquired by the control unit 15. Yes. The image sensor 24 is electrically connected to the control unit 15 of the lighting fixture 21 by plug-in. The lens 14L is attached to the image sensor 24. The storage unit 25 includes a nonvolatile memory or the like. Other configurations are the same as those of the first embodiment.

  Thus, the present system 20 is a plug-in type in which the image sensor 24 can be replaced, and a dimming rate capable of identifying the detected object on the image data can be stored in the storage unit 25 of the image sensor 24 in advance. Therefore, the dimming rate can be easily set by replacing the image sensor 24.

  Operation types such as N type, A type, AN type, etc. are set on the lighting fixture 21 side of the system 20, and when the image sensor 24 is plugged in, dimming control is performed with the automatically set operation type. You may do it. The operation type can be freely changed in setting, and is stored in, for example, a nonvolatile memory in which a program executed by the CPU of the control unit 15 is stored.

  Further, the operation type setting may be stored in the storage unit 25 of the image sensor 24. When the image sensor 24 is plugged into the lighting fixture 21, the control unit 15 reads the operation type set with reference to the storage unit 25 of the image sensor 24, and automatically performs dimming control with the operation type. The operation type stored in the storage unit 25 can be freely set and changed. When the operation type (N type, AN type) for performing human body detection is stored in the storage unit 25, the dimming rate at which the control unit 15 can identify the detected object on the image data is stored in the same storage unit 25.

  That is, the present system 20 acquires the light source 12, the lighting circuit 13 that lights the light source 12, the image sensor 24, and image data output from the image sensor 24, and performs image processing on the image data to perform the lighting circuit. The image sensor 24 is of a plug-in type and includes a storage unit 25 that stores information referred to by the control unit 15. Stores information on whether or not to perform human body detection by image processing (operation type such as N type, A type, AN type), and when performing human body detection by image processing (in the case of N type or AN type), The storage unit 25 stores a dimming rate that allows the human body to be identified on the image data acquired by the control unit 15, and the control unit 15 uses the dimming rate that allows the human body to be identified on the acquired image data. The turning on.

  Thereby, in the operation type (N type, AN type) that performs human body detection, it is possible to reliably perform human body detection without causing darkness that human body detection is not possible. Moreover, in the operation type (A type) which does not perform human body detection, it can be turned off depending on the intensity of outside light, and energy saving can be achieved.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the operation type and the dimming rate may be stored in a storage device that is fixed to the lighting fixture and is detachably provided on the lighting fixture.

The functional block diagram of the illumination system which concerns on the 1st Embodiment of this invention. The figure explaining control of the load current by the light control signal in the system. (A) is a figure which shows a time-dependent deterioration of the light source of the system, (b) is a figure which shows the example of a setting of the light control rate for compensating a time-dependent deterioration. The figure explaining the setting method of the light control rate in the same system. The functional block diagram of the illumination system which concerns on the 2nd Embodiment of this invention. The block diagram of the conventional lighting fixture which has a photodiode. The block diagram of the conventional lighting fixture which has a pyroelectric element. (A) is explanatory drawing of a stationary human body detection using the image pick-up element in the conventional illumination system, (b) is explanatory drawing of the operation | movement human body detection using the same image pick-up element. Explanatory drawing of the brightness measurement using the image sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 Illumination system 12 Light source 13 Lighting circuit 14 Image sensor 15 Control part 24 Plug-in type image sensor 25 Memory | storage part

Claims (2)

Control for generating a dimming control signal for the lighting circuit by acquiring a light source, a lighting circuit for lighting the light source, an image sensor, and image data output from the image sensor, and performing image processing on the image data A lighting system comprising:
The said control part makes the said light source light with the light control rate which can identify a detected object on the acquired image data, The illumination system characterized by the above-mentioned. The image sensor is of a plug-in type, and includes a storage unit that stores information referred to by the control unit,
The lighting system according to claim 1, wherein a dimming rate capable of identifying the detected object on the image data acquired by the control unit is stored in the storage unit.

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