JP2006259407A - Imaging apparatus and control method for illuminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus using LEDs (light emitting diodes) in R, G, B colors, which is designed so that a subject can be illuminated without burden on power source voltage, and to provide a control method for an illuminating device. <P>SOLUTION: The lighting timings of the LEDs in the respective colors are shifted from one another. Lighting luminance is controlled by the lighting time of each LED. A color temperature is controlled by a ratio between the lighting times of the LEDs in the respective colors. The lighting times of the LEDs and the ratio between the lighting times of the LEDs are determined by illuminating control conditions corresponding to photographing conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photographing apparatus and a lighting device control method, and more particularly, to a photographing apparatus and a lighting device control method using RGB LEDs as light sources.

  In a conventional photographing apparatus, a strobe that emits light from a Xe discharge tube (xenon discharge tube) is generally used as a flash light source.

  However, since a high voltage of 300 V or higher is usually applied to make the strobe emit light, it is necessary to provide a booster circuit such as a DC / DC converter and a large-capacity capacitor capable of generating a large current instantaneously. is there. In addition, complicated circuits such as a trigger circuit for causing the Xe discharge tube to emit light and a dimming circuit for appropriately controlling the light emission amount are required, which is a major factor that hinders downsizing and cost reduction of the photographing apparatus. It was.

  In addition, the strobe using the Xe discharge tube has a number of problems that it takes time to charge the above-mentioned large-capacity capacitor, so that the strobe photography cannot be performed at a photo opportunity.

  By the way, in recent years, the sensitivity of photographic film has increased to ISO sensitivity 800 to 1600, and further, the sensitivity of a CCD (charge coupled device) image sensor of a digital still camera (electronic camera) has also increased. A large amount of light like a strobe is no longer necessary.

  Therefore, in recent years, many photographing apparatuses that illuminate a subject using high-intensity LEDs (light-emitting diodes) having emission colors such as red, green, blue, and white have been used.

  The following are known as techniques relating to an imaging device using an LED.

  Japanese Patent Application Laid-Open No. 2004-228688 proposes a technique of a photographing illumination device that includes a plurality of white light emitting diodes and selectively emits the white light emitting diodes according to the distance from the subject. Patent Document 2 proposes a technique of a photographic illumination device that includes a plurality of white light emitting diodes and selectively emits the white light emitting diodes based on information detected by the distance measuring unit and the photometric unit. .

Patent Document 3 and Patent Document 4 propose a technique of a strobe photographing device that uses each RGB LED and adjusts the amount of light emitted from each LED so that the strobe light has a desired color temperature. Yes.
Japanese Patent No. 3584355 JP 2002-148686 A JP 2002-116481 A JP 2003-215673 A

  However, the above technique has the following problems.

  In the techniques of Patent Documents 1 and 2, since only white LEDs are used, fine adjustment to the color temperature of the shooting environment cannot be performed, and in some cases, unclear photographs are formed.

  Further, in the techniques of Patent Documents 3 and 4, it is necessary to flow a large current for all the LEDs (R + G + B) at the time of strobe shooting, which places a burden on the power supply voltage and reduces the life of the battery power supply. is there.

  The present invention has been made in view of the above problems, and in an imaging apparatus using RGB color LEDs (light emitting diodes), an imaging apparatus capable of illuminating a subject without imposing a burden on the power supply voltage, and It is an object of the present invention to provide a method for controlling a lighting device.

  The invention described in claim 1 is a photographing apparatus for illuminating a subject under exposure by an illuminating device having light emitting diodes of R, G, and B colors, and the illuminating device illuminates the light emitting diodes of each color one by one. An imaging apparatus that illuminates the subject under exposure by continuously turning on.

  According to a second aspect of the present invention, in the photographing apparatus according to the first aspect, the luminance of the illumination is adjusted according to an illumination time for illuminating the subject of the illumination device.

  According to a third aspect of the present invention, in the photographing apparatus according to the first or second aspect, the color temperature of illumination is adjusted by a ratio of lighting times of the light emitting diodes of the respective colors.

  According to a fourth aspect of the present invention, in the photographing apparatus according to the third aspect, the photographing apparatus includes a reading unit that reads a photographing condition, and illuminates the subject according to the photographing condition read by the reading unit. The illumination time and the lighting time ratio of the light emitting diodes of the respective colors are determined.

  According to a fifth aspect of the present invention, in the photographing apparatus according to the fourth aspect, the photographing condition includes a distance to the subject, a color temperature of the subject, an aperture of the photographing device, and an image amplification factor of the photographing device. It is characterized by being at least one.

  According to a sixth aspect of the present invention, in the photographing apparatus according to any one of the first to fifth aspects, the amount of current flowing through the light emitting diode of each color is substantially the same for each color.

  A seventh aspect of the present invention is the imaging apparatus according to any one of the first to sixth aspects, wherein a plurality of the light emitting diodes for each color are provided for each color.

  According to an eighth aspect of the present invention, in the photographing apparatus according to the seventh aspect, in the plurality of light emitting diodes of each color, R-light emitting diodes are arranged in series, and the G-light emitting diode and the B-light emitting diode are They are arranged in parallel connection.

  The invention according to claim 9 is the imaging apparatus according to any one of claims 1 to 8, wherein the illumination time for illuminating the subject of the illumination device is longer than the exposure time of the imaging device. The image amplification factor is changed.

  According to a tenth aspect of the present invention, in the photographing apparatus according to the ninth aspect, when the illumination time for illuminating the subject of the lighting device is longer than the exposure time of the photographing device even if the image amplification factor is changed. Has an informing means for informing the outside to that effect.

  The invention according to claim 11 is a method of controlling an illuminating device that illuminates a subject under exposure using light emitting diodes of R, G, and B colors, wherein the light emitting diodes of each color are continuously turned on one by one. And adjusting the brightness of the illumination according to the illumination time for illuminating the subject of the illumination device, and adjusting the color temperature of the illumination according to the ratio of the lighting times of the light emitting diodes of the respective colors. is there.

  According to a twelfth aspect of the present invention, in the method of controlling an illuminating device according to the eleventh aspect, the illumination time for illuminating the subject and the lighting time ratio of the light emitting diodes of the respective colors are determined according to shooting conditions. It is characterized by.

  In the present invention, lighting control is performed by shifting the lighting timing of each color LED. The illumination brightness is controlled by the LED lighting time, and the color temperature is controlled by the lighting time ratio of each color LED. By controlling in this way, the electric current supplied to LED of an illuminating device can be averaged (it makes constant value). As a result, the load current from the power source can be made constant, the voltage drop can be reduced, and the battery life can be prevented from decreasing.

  First, with reference to FIG. 1, the structure of the imaging device of this embodiment is demonstrated.

  The photographing apparatus 10 includes a CPU 11, a lens barrel unit 12, a CCD 13, an image processing circuit 14, a ROM 15, a RAM 16, a main memory 17, an SRAM 18, an SDRAM 19, a memory card 20, an auxiliary memory 21, A liquid crystal monitor 22, an operation panel 23, a release button 24, an external I / O 25, an audio recording unit 26, an audio reproducing unit 27, a photometric sensor 28, a distance measuring sensor 29, an LED illumination device 30, Consists of

  The CPU 11 controls the operation of the photographing apparatus 10 according to a program. Also, white balance setting, gamma setting, and JPEG compression / decompression are performed on the output data of the image processing circuit 14. Also, interpolation control (enlargement / reduction) of image data size and conversion control of luminance data and color difference data are performed.

  The lens barrel unit 12 includes a lens (zoom / focus) for taking an image of a subject into the CCD 13, a diaphragm, a mechanical shutter, a motor driver for moving these, and the like, and is driven and controlled by the CPU 11.

  The CCD 13 photoelectrically converts the image captured from the lens barrel unit 12.

  The image processing circuit 14 includes a correlated double sampling circuit for removing image noise, a gain adjustment circuit, and a digital signal conversion circuit, and performs these image processes on the subject image data sent from the CCD 13.

  The ROM 15 holds a control program and control parameters for the CPU 11. When the photographing apparatus 10 is turned on, the control program is loaded into the main memory 17. The CPU 11 controls the operation of each part of the photographing apparatus 10 according to this program. Data necessary for control is temporarily stored in the RAM 16 and the SRAM 18.

  Note that by using a rewritable flash ROM as the ROM 15, it becomes possible to change the control program and control parameters, and the device functions can be easily upgraded.

  The SDRAM 19 temporarily stores image data when the CPU 11 performs various processes on the image data. As saved image data, “RAW-RGB image data” obtained by white balance setting / gamma setting and luminance data / color difference data conversion are obtained from the CCD 13 via the image processing circuit 14. “YUV image data” and “JPEG image data” compressed with JPEG are listed.

  The memory card 20 is a storage unit configured to be detachable from the photographing apparatus 10. By storing image data in this, it becomes possible to exchange image data between devices.

  The auxiliary memory 21 is an auxiliary memory that holds captured image data even when the memory card 20 is not attached to the imaging apparatus 10.

  The liquid crystal monitor 22 monitors a subject before photographing, confirms a photographed image, displays image data recorded in the memory card 20 and the auxiliary memory 21, and displays the remaining battery level and photographing mode of the photographing apparatus 10.

  The operation panel 23 accepts various inputs from the user such as a change in shooting mode. The release button 24 is a switch that triggers shooting. When this button is pressed, the mechanical shutter of the lens barrel unit 12 is opened and the subject image is taken into the shooting apparatus 10.

  The external I / O 25 is an input / output circuit for performing serial communication with an external device such as a personal computer.

  The audio recording unit 26 is a part for recording external sound, and includes a microphone for inputting an audio signal, a microphone AMP for amplifying the input audio signal, and an audio recording circuit for recording the amplified audio signal. The

  The audio reproduction unit 27 is a part that outputs audio, an audio reproduction circuit that converts a recorded audio signal into a signal that can be output from a speaker, an audio AMP that amplifies the converted audio signal and drives the speaker, And a speaker for outputting an audio signal.

  The photometric sensor 28 measures the color temperature of the subject.

  The distance measuring sensor 29 measures the distance from the photographing apparatus 10 to the subject.

  The LED illumination device 30 is composed of LEDs (light-emitting diodes) of R (red), G (green), and B (blue), and illuminates a subject at the time of shooting.

  FIG. 2 shows the configuration of the LED lighting device 30. A control signal corresponding to each color LED 32 is transmitted from the CPU 11 to the drive circuit 31, and on / off of each color LED 32 is controlled based on this signal.

  Next, illumination control of the LED illumination device 30 in the present embodiment will be described.

  In the present embodiment, lighting control is performed by shifting the lighting timing of each color LED 32 of the LED lighting device 30. The illumination brightness of the LED lighting device 30 is controlled by the lighting time of the LED 32, and the color temperature of the LED lighting device 30 is controlled by the lighting time ratio (lighting time ratio) of each color LED 32. By controlling in this way, the electric current supplied to LED of an illuminating device can be averaged (it makes constant value). As a result, it is not necessary to flow a large current as in a conventional photographing apparatus, the load current from the power source can be made constant, the voltage drop can be reduced, and the battery life can be prevented from being lowered. .

  Hereinafter, specific description will be given with reference to the drawings. FIG. 3 shows an illumination control flow of the LED illumination device 30 of the present embodiment.

  First, the CPU 11 reads photographing conditions (S101). The shooting conditions here are conditions such as the distance to the subject (shooting distance), the color temperature state of the subject, the aperture, and the image amplification factor. The distance to the subject is measured using the distance measuring sensor 28, and the color temperature state of the subject is measured using the photometric sensor 29. The reading of the shooting conditions is performed after the release button 24 is pressed and before the mechanical shutter is opened and the subject is captured.

  Next, the CPU 11 acquires illumination control data of the LED illumination device 30 based on the read photographing condition (S102). The illumination control data is data that determines the lighting time of the LED 32 and the lighting time ratio of the LED 32. This illumination control data is stored in advance in the ROM 15 as a data table.

  Next, the CPU 11 determines whether or not the LED illumination shooting mode is set (S103). When it is not in the LED illumination photographing mode (S104 / No), it is not necessary to perform the illumination control of the LED illumination device 30, and the subject photographing operation (exposure operation) is started as it is (S106).

  On the other hand, when the LED illumination photographing mode is set (S104 / Yes), the illumination control of the LED illumination device 30 is performed based on the obtained illumination control data, and photographing is performed (S105, S106). The illumination brightness is controlled and adjusted by the lighting time of the LED 32, and the color temperature of the lighting is controlled by the lighting time ratio of each color LED 32.

  An example will be described. As a result of reading the photographing conditions, the illumination time of the LED illumination device 30 for obtaining an appropriate illumination brightness is 10 msec, and the light emission ratio of each color LED 32 for obtaining an appropriate color temperature is R: G: B = 3: 6: 1. In this case, as shown in FIG. 4, the R-LED is turned on for 3 msec, the G-LED is turned on for 6 msec, and the B-LED is turned on for 1 msec during the illumination time of 10 msec. Since it has been found that the light emitted during exposure (the state in which the mechanical shutter is open and the subject is taken in) is mixed and integrated, all the colors can be obtained even if single lighting is continuously performed in this way. It is possible to obtain the same color temperature as when the lighting is performed.

  In this illumination control, it is preferable that the current flowing through each color LED 32 is constant, that is, constant current driving is performed. By controlling in this way, it becomes possible to facilitate the averaging of the current supplied to each color LED 32 when the illumination control of the LED lighting device 30 is performed. In addition, it is possible to reduce the influence due to temperature change and power supply voltage fluctuation.

  In addition to the above method, the ratio of currents flowing through the respective color LEDs 32 may be set to R: G: B = 3: 6: 1, and the respective color LEDs 32 may be sequentially turned on every 10 msec.

  The LED lighting device 30 may be provided with a plurality of each color LED 32. By comprising in this way, an increase in illumination brightness and an increase in the light distribution angle of the LED illumination device 30 can be achieved. When a plurality of LEDs 32 are provided for each color, the number of LEDs may be the same for each color or may be different for each color.

  Since the lighting voltage of the R-LED is about half of the lighting voltage of the G-LED and the B-LED, for example, when arranging each LED of two colors, the R-LED is connected in series as shown in FIG. Arranging and arranging G-LEDs and B-LEDs in parallel makes it possible to increase circuit efficiency.

  In the above-described illumination control, when the illumination time of the LED illumination device 30 for achieving the illumination brightness obtained from the imaging conditions exceeds the exposure time (time during which the mechanical shutter is open), it corresponds to the imaging conditions. The illumination brightness to be obtained cannot be obtained.

  Therefore, as in the control flow of FIG. 6, when the illumination time of the LED illumination device 30 is longer than the exposure time in the illumination control data corresponding to the shooting conditions (S115 / No), the amplification factor of the image is changed ( (S116), the illumination control data of the LED illumination device 30 is acquired under the condition with the amplification factor changed (S112). Then, the illumination control of the LED illumination device 30 is performed based on the acquired illumination control data, and exposure / photographing is performed (S118, S119). By controlling in this way, shooting can be performed under various shooting conditions, which can contribute to the user.

  If the illumination time is longer than the exposure time even if the image amplification factor is changed, in other words, if the shooting condition exceeds the capability of the shooting apparatus, an under or hand on the liquid crystal monitor 22 or the operation panel 23 is displayed. Control to perform notification such as blur warning. By controlling in this way, it is possible to give a warning to the user and contribute to the user.

It is a figure which shows the structure of an imaging device. It is a figure which shows the structure of a LED lighting apparatus. It is a figure which shows the flow of the illumination control of a LED lighting apparatus. It is a figure for demonstrating the lighting timing of each color LED. It is a figure which shows the structure of the illuminating device which provided multiple LED. It is a figure which shows the flow of the illumination control of a LED lighting apparatus.

Explanation of symbols

10 photographing device 11 CPU
28 Photometric sensor 29 Distance sensor 30 LED lighting device 32 LED (R, G, B)

Claims (12)

An imaging device that illuminates a subject under exposure by an illumination device having light emitting diodes of R, G, and B colors,
The illuminating device illuminates the subject under exposure by continuously lighting the light emitting diodes of the respective colors one by one.   The photographing apparatus according to claim 1, wherein the luminance of the illumination is adjusted according to an illumination time for illuminating the subject of the illumination device.   The photographing apparatus according to claim 1, wherein the color temperature of the illumination is adjusted according to a ratio of lighting times of the light emitting diodes of the respective colors. The photographing apparatus has a reading means for reading photographing conditions,
4. The photographing apparatus according to claim 3, wherein the illumination time for illuminating the subject and the lighting time ratio of the light emitting diodes of the respective colors are determined in accordance with the photographing condition read by the reading unit.   5. The photographing apparatus according to claim 4, wherein the photographing condition is at least one of a distance to the subject, a color temperature of the subject, an aperture of the photographing device, and an image amplification factor of the photographing device. .   6. The photographing apparatus according to claim 1, wherein the amount of current flowing through the light emitting diode of each color is substantially the same for each color.   7. The photographing apparatus according to claim 1, wherein a plurality of light emitting diodes of each color are provided for each color.   8. The plurality of light emitting diodes of each color, wherein R-light emitting diodes are arranged in series, and G-light emitting diodes and B-light emitting diodes are arranged in parallel. Shooting device.   The imaging according to any one of claims 1 to 8, wherein an image amplification factor is changed when an illumination time for illuminating the subject of the illumination device is longer than an exposure time of the imaging device. apparatus.   In the case where the illumination time for illuminating the subject of the illumination device is longer than the exposure time of the photographing device even if the image amplification factor is changed, it has a notification means for informing the outside to that effect. The imaging device according to claim 9. A method for controlling an illumination device that illuminates a subject under exposure using light emitting diodes of R, G, and B colors,
The light emitting diodes of each color are continuously lit one by one,
Adjusting the brightness of the illumination according to the illumination time for illuminating the subject of the illumination device;
A method for controlling an illumination device, comprising: adjusting a color temperature of illumination according to a ratio of lighting times of light emitting diodes of the respective colors.   12. The method of controlling an illumination device according to claim 11, wherein the illumination time for illuminating the subject and the lighting time ratio of the light emitting diodes of the respective colors are determined according to photographing conditions.

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