JP5979880B2 - Illumination device and imaging system - Google Patents

Description

  The present invention relates to an illumination device capable of attaching an optical accessory that changes the color characteristics of transmitted light to the front of a light emitting unit, and an imaging system including the illumination device.

  Generally, in an illumination device such as a strobe device used in a camera, a discharge tube such as a xenon tube is used as the light source. The color temperature of irradiation light (strobe light) in a strobe device using a xenon tube is set near sunlight (6000 K). For this reason, when shooting is performed using a strobe device in an environment having a color temperature different from the color temperature, an unnatural color captured image may be obtained.

  Therefore, Patent Document 1 proposes a technique of changing the color temperature of the irradiation light of the strobe device by attaching a filter holder with an optical accessory such as a color filter attached in front of the light emitting unit of the strobe device. In Patent Document 1, identification information for identifying the type of a color filter is added to the color filter side, and the color filter attached to the filter holder is read by reading the identification information of the color filter with a reading unit provided on the strobe device side. Identify the type of filter. Then, the strobe device determines the color temperature of the irradiation light from the identified type of the color filter, and displays the color temperature information on the display unit or transmits the color temperature information to the attached camera.

JP 2009-20298 A

  However, in the technique disclosed in Patent Document 1, since the identification information is read to identify the type of the color filter, the type of color filter to which no identification information is added cannot be identified.

  If the identification information can only be read from one side of the color filter, the type of color filter can of course be identified by attaching the color filter to the filter holder so that the side where the identification information cannot be read is on the reading unit side. I can't.

  Further, in order to read the identification information and identify the type of the color filter, it is necessary to read the identification information accurately. For example, if the identification information can be read from either side of the color filter, but the shape or pattern of the identification information differs depending on the surface to be read, if the wrong side of the color filter is attached to the filter holder, the color temperature will be mistakenly identified and the color temperature will be There is a risk of misjudgment. Further, since the identification information described in Patent Document 1 includes a plurality of unit information, in order to read such identification information, it is necessary to have a configuration in which the reading position of the strobe device can be changed. The number of points increases, which increases the size and cost of the strobe device.

  Accordingly, an object of the present invention is to make it possible to accurately determine the color characteristic of an optical accessory regardless of the mounting direction of the optical accessory that changes the color characteristic of transmitted light.

In order to achieve the above object, an illuminating device according to the present invention is an illuminating device in which an optical accessory that changes a color characteristic of transmitted light can be attached to the front of a light emitting unit, and includes a light source, a light receiving unit, Based on a light reception result of the light received from the light source and transmitted through the optical accessory by the light receiving means and a light reception result of the ambient light received by the light receiving means when the light source is not emitting light . Discriminating means for discriminating color characteristics.

In order to achieve the above object, a camera system according to the present invention includes an illumination device capable of attaching an optical accessory that changes the color of transmitted light in front of a light emitting unit, a light source, a light receiving unit, A light guide that guides the light emitted from the light source in the direction of the light receiving means so that the light emitted from the light source passes through an optical accessory attached to the lighting device and is received by the light receiving means; Discriminating means for discriminating the color of the optical accessory based on the result of receiving the light emitted from the light source by the light receiving means and the result of receiving the ambient light by the light receiving means when the light source is not emitting light. And an imaging unit that images the subject irradiated with the illumination light of the illumination device, and a white that corrects the white balance of the output of the imaging unit based on the output of the determination unit And having a lance correcting means.

  According to the present invention, the color characteristic of the optical accessory can be accurately determined regardless of the mounting direction of the optical accessory that changes the color characteristic of the transmitted light.

1 is a block diagram illustrating a configuration of an imaging system according to an embodiment of the present invention. (A)-(c) is a figure which shows the structure of the filter holder 10 which concerns on embodiment of this invention. It is a figure which shows the relationship between the filter holder 10 and filter discrimination | determination part 324 which concern on embodiment of this invention. (A) is an internal block diagram of the part regarding the holder discrimination | determination part 322 and the filter discrimination | determination part 324 in the state which faced the lower surface of the light emission part 350 which concerns on embodiment of this invention. (B) is a perspective view of the state where the inside of the cover 21 of the light emitting unit 350 according to the embodiment of the present invention faces upward. It is sectional drawing seen from the side surface of the light emission part 350 which concerns on embodiment of this invention. (A) is the figure which showed the example of the result of having received the light emitted from the light source 26 and having permeate | transmitted the color filter 16 once by the color sensor 27. FIG. (B) is a diagram showing an example of a result of receiving light emitted from the light source 26 and transmitted through the color filter 16 twice by the color sensor 27. It is a figure which shows the flowchart of the discrimination process of the color characteristic of the color filter 16 in 1st Embodiment. It is a figure which shows the range considered as the result which permeate | transmitted the same color filter in the detection result of the color sensor 27. FIG. FIG. 9 is a diagram illustrating a table in which the detection result of the color sensor 27 illustrated in FIG. 8 is associated with the color temperature of the color filter 16. It is a figure which shows the flowchart of the discrimination | determination process of the color characteristic of the color filter 16 in 2nd Embodiment. It is a figure which shows the spectral characteristic of the light source 26, the discharge tube 307, and the spectral sensitivity characteristic of the color sensor 27. It is a figure which shows the flowchart of the discrimination process of the color characteristic of the color filter 16 in 3rd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration of an imaging system according to the present embodiment. The imaging system according to the present embodiment includes a camera body 100 that is an imaging device, a lens unit 200 that can be attached to and detached from the camera body 100, and a flash device 300 that is an illumination device that can be attached to and detached from the imaging device. In the strobe device 300, a filter holder 10 as an optical accessory to be described later is detachable, and a device in which the filter holder 10 is attached to the strobe device 300 is hereinafter referred to as an illumination system.

  First, the configuration inside the camera body 100 will be described. A camera microcomputer (CCPU) 101 controls each part of the camera body 100. The camera microcomputer 101 is a one-chip IC circuit with a built-in microcomputer including, for example, a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, etc. It has a configuration.

  The image sensor 102 is an image sensor such as a CCD or CMOS including an infrared cut filter, a low-pass filter, and the like. The shutter 103 is driven to shield the image sensor 102 when not photographing, and to guide a light beam to the image sensor 102 when photographing.

  The main mirror (half mirror) 104 reflects a part of light incident from a lens group 202 (to be described later) during non-photographing and forms an image on the focus plate 105. The image on the focus plate 105 is guided to the optical viewfinder 116 or the like via the pentaprism 114 and used to confirm the in-focus state of the subject.

  The photometric circuit 106 includes a photometric sensor (AE sensor) that divides the photographing screen into a plurality of photometric areas and performs photometry in each photometric area. The focus detection circuit 107 has a focus detection sensor (AF sensor) having a plurality of distance measuring points in the shooting screen.

  The gain switching circuit 108 switches the amplification gain of the signal from the image sensor 102, and the camera microcomputer 101 switches the gain according to shooting conditions, level setting based on a charging voltage condition described later, input by the photographer, and the like.

  The A / D converter 109 converts the amplified analog signal from the image sensor 102 into a digital signal. The timing generator (TG) 110 is used to synchronize the signal from the image sensor 102 and the conversion timing of the A / D converter 109.

  The digital signal processing circuit 111 performs image processing including white balance control on the image data converted into a digital signal by the A / D converter 109.

  The signal line SC is a signal line for an interface between the camera body 100, the lens unit 200, and the strobe device 300. For example, the camera microcomputer 101 is used as a host to exchange data and transmit commands to each other.

  The input unit 112 includes various operation units such as a release switch for starting a photographing operation. For example, the display unit 113 including a liquid crystal device, a light emitting element, and the like displays various settings and shooting information.

  The pentaprism 114 guides the light beam incident from the lens group 202 and reflected by the main mirror 104 to the AE sensor and the optical viewfinder 116 in the photometry circuit 106.

  The sub mirror 115 guides the light beam incident from the lens group 202 and transmitted through the semitransparent portion at the center of the main mirror 104 to the AF sensor of the focus detection circuit 107.

  Next, the configuration and operation within the lens unit 200 will be described. A lens microcomputer (LPU) 201 controls the operation of each part of the lens unit 200. The lens microcomputer 201 includes, for example, a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, and the like. It has become.

  The lens group 202 is composed of a plurality of lenses, and the lens driving unit 203 moves the lens group 202 in accordance with an instruction from the lens microcomputer 201 such as focus adjustment and change of focal length.

  The encoder 204 detects the position of the lens group 202 or the driving amount of the lens group 202. By transmitting the position information or drive information of the encoder 204 from the lens microcomputer 201 to the camera microcomputer 101, the camera microcomputer 101 can acquire information regarding the subject distance at the time of shooting. The diaphragm 205 adjusts the amount of light incident on the image sensor 102 by changing the aperture diameter, and is controlled by the lens microcomputer 201 via the diaphragm control circuit 206.

  Next, the configuration of the strobe device 300 as an illumination device will be described. The battery 301 supplies power for the strobe device (VBAT), and the booster circuit 302 boosts the voltage of the battery 301 to several hundred volts and charges the main capacitor 303. The charging voltage of the main capacitor 303 is divided by the resistor 304 and the resistor 305 in the voltage detection circuit 313, and the divided voltage is input to the strobe microcomputer 310. That is, the voltage detection circuit 313 is connected to both ends of the main capacitor 303 and detects the voltage of the main capacitor.

  The trigger circuit 306 is connected to the strobe microcomputer 310 and outputs a trigger voltage when receiving a trigger signal from the strobe microcomputer 310 when the discharge tube 307 emits light. The discharge tube 307 is a main light source that emits light using energy charged in the main capacitor 303 by receiving and exciting a trigger voltage of several KV applied from the trigger circuit 306.

  The light emission control circuit 308 controls the start of light emission of the discharge tube 307 by the trigger voltage from the trigger circuit 306, and controls the stop of light emission by the output of an AND gate 311 described later. The integration circuit 309 is an integration circuit that integrates the current generated when the photodiode 323 receives the irradiation light of the discharge tube 307, and the output of the integration circuit 309 is input to the inverting input terminal of the comparator 312 and the strobe microcomputer 310. .

  A strobe microcomputer (FPU) 310 controls the operation of each unit of the strobe device 300. The strobe microcomputer 310 is a one-chip IC circuit configuration with a built-in microcomputer including, for example, a CPU, ROM, RAM, input / output control circuit (I / O control circuit), multiplexer, timer circuit, EEPROM, A / D converter, D / A converter, etc. It has become. The strobe microcomputer 310 determines whether or not the filter holder 10 is attached and determines the color characteristics of the color filter 16 as described later.

  The comparator 312 has a non-inverting input connected to the strobe microcomputer 310 and an output connected to the AND gate 311. The AND gate 311 has an input not connected to the comparator connected to the flash microcomputer 310 and an output connected to the light emission control circuit 308. In this way, the integration level of the integration circuit 309 is compared with the reference level set by the flash microcomputer 310, and when the integration level of the integration circuit 309 reaches the reference level, the stop of light emission is controlled.

  The reflector 315 reflects the light emitted from the discharge tube 307 in the irradiation direction of the light emitting unit 350. The optical system 316 is an irradiation unit that reduces unevenness of light irradiated from the discharge tube 307 and widens the irradiation range of light irradiated from the discharge tube 307. The input unit 320 includes various operation units for inputting settings of the flash device 300 and the like. The display unit 321 displays various states of the strobe device 300.

  The holder discriminating unit 322 discriminates whether or not the detachable filter holder 10 is attached to the light emitting unit 350, and the strobe microcomputer 310 performs filtering based on the detection result of the holder discriminating unit 322. It is determined whether or not the holder 10 is attached. The detailed structure and determination method of the filter holder 10 will be described later.

  The photodiode 323 is a sensor that receives the irradiation light of the discharge tube 307 as described above, and receives the irradiation light of the discharge tube 307 directly or via a glass fiber or the like. The current output from the photodiode 323 is integrated by the integration circuit 309 as described above.

  The filter discriminating unit 324 discriminates the color characteristics of the color filter 16 held in the filter holder 10 as shown in FIGS. 2 and 3, and the strobe microcomputer 310 is based on the detection result of the filter discriminating unit 324. Determines the color characteristics of the color filter. The detailed structure and discrimination method of the filter discrimination unit 324 will be described later.

  The light emitting unit 350 is a block mainly including the discharge tube 307, the reflector 315, the optical system 316, the detection system of the holder discrimination unit 322, and the detection system of the filter discrimination unit 324. They are connected by a hinge mechanism (not shown) and can be rotated in the vertical direction.

  2A to 2C show details of the filter holder 10. 2A is a perspective view of the filter holder 10 viewed from the light emitting unit 350 side (back side), and FIG. 2B is a diagram illustrating a state in which the color filter 16 or the color filter 16 ′ is mounted on the filter holder 10. It is. FIG. 2C is a view of the filter holder 10 in the state of FIG. 2B viewed from the front side (subject side).

  A light blocking block 19 is provided on the lower surface of the filter holder 10. The light blocking block 19 uses a strobe microcomputer 310 using a prism 18 for reflecting light for filter discrimination from the light emitting unit 350 and a magnetic sensor to be described later as to whether or not the filter holder 10 is attached to the light emitting unit 350. The magnet 17 for discriminating is incorporated.

  Further, the light shielding block 19 has two protrusions 29 for fixing the filter holder 10 to the concave portion 350a (described in FIG. 5) of the light emitting unit 350 when the filter holder 10 is attached to the light emitting unit 350. ing. The protrusion 29 has a hook shape and is also used as a holding portion for holding the color filter 16 by the filter holder 10 as shown in FIG. When the color filter 16 is attached to the filter holder 10, as shown in FIG. 2C, one end of the color filter 16 is inserted into a slit 32 provided on the upper portion of the filter holder 10, and the other end is a protrusion. It is sandwiched between 29 hook-shaped parts. In this way, the color filter 16 is held in the filter holder 10. The shape of the color filter may be any shape as long as it can be inserted into the slit 32 and sandwiched between the protrusions 29, and may be a shape such as 16 indicated by a solid line in FIGS. 2B and 2C. The shape may protrude from the filter holder 10 such as 16 'indicated by a dotted line.

  The holder discriminating unit 322 of the present embodiment detects the magnet 17 on the filter holder 10 side using a magnetic sensor 25 described later. Based on the detection result, the flash microcomputer 310 determines whether or not the filter holder 10 is attached to the light emitting unit 350. Therefore, it is not necessary to make the holder discriminating unit 322 protrude outside the filter holder 10 or the light emitting unit 350, and it is possible to discriminate whether or not the holder is mounted although the magnet 17 is disposed at a position covered by the color filter 16. Moreover, the filter holder 10 can be reduced in size by arrange | positioning the magnet 17 between the two projection parts 29 and the irradiation surface side rather than the two projection parts 29. FIG.

  FIG. 3 is a schematic view of the light emitting unit 350 with the filter holder 10 mounted, as viewed from the front, and shows a cross-sectional structure of the detection system of the filter holder 10 including the color filter 16 and the filter discriminating unit 324. The color filter 16 changes the color characteristic of the transmitted light. The filter holder 10 holding the color filter 16 is attached to the light emitting unit 350, thereby changing the color characteristic of the irradiation light of the light emitting unit 350. be able to. Note that filters of various colors can be attached to the filter holder 10 as the color filter 16, and the color characteristics of the irradiation light of the light emitting unit 350 can be changed variously by changing the filter attached to the filter holder 10. it can.

  In FIG. 3, a light source 26 is a light source such as a white LED and emits light for color filter discrimination. The color sensor 27 is a light receiving unit in which, for example, a plurality of photodiodes are provided with color filters having different spectral characteristics. The prism 18 is a prism for causing the light emitted from the light source 26 to enter the color sensor 27, and functions as a light guide that guides the light emitted from the light source 26 to the color sensor 27.

  As shown in FIG. 3, the light from the light source 26 passes through the color filter 16, is reflected twice by the prism 18 of the filter holder 10, passes through the color filter 16 again, and then enters the color sensor 27. Since the color characteristics of the color filter 16 held by the filter holder 10 are determined using the light source 26 and the color sensor 27 in this way, the mounting direction of the color filter 16 (which surface should be the light emitting unit 350 side). Etc.), the color characteristics of the color filter can be determined.

  FIG. 4 is a diagram showing an internal structure below the light emitting unit 350 of the strobe device 300, and mainly shows a part related to the detection system of the holder discriminating unit 322 and the detection system of the filter discriminating unit 324. 4A is a diagram in which the lower surface of the light emitting unit 350 is directed upward, and FIG. 4B is a diagram in which the inside of the lower cover 21 of the light emitting unit 350 is directed upward.

  A light-shielding member that suppresses unnecessary light from entering the magnetic sensor 25 for detecting the magnet 17 on the holder side, the light source 26, the color sensor 27, and the color sensor 27 on the substrate 24 provided inside the light emitting unit 350. The microcell polymer sheet 28 is arranged.

  By arranging the magnetic sensor 25, the light source 26, and the color sensor 27 in a direction substantially orthogonal to the optical axis of the light emitted from the light emitting unit 350, the magnet 17 and the prism 18 of the filter holder 10 also have the optical axis of the light emitted from the light emitting unit 350. They can be arranged in a substantially orthogonal direction. Thereby, the length in the direction parallel to the optical axis of the irradiation light of the light emitting part 350 of the light shielding block 19 of the filter holder 10 can be suppressed, and the filter holder 10 can be downsized.

  The lower cover 21, which is the exterior of the lower surface (upper surface in FIG. 4) of the light emitting unit 350, the irradiation window 22 for irradiating the light from the light source 26 to the outside of the light emitting unit 350, and the reflected light from the prism 18. Is incident on the color sensor 27. The shape of the prism 18 of the filter holder 10 is set such that the light emitted from the irradiation window portion 22 efficiently enters the incident window portion 23. For example, in the present embodiment, the light emitted from the irradiation window 22 by the prism 18 is reflected by the first reflecting surface 18a in FIG. 3, and the light reflected by the first reflecting surface is reflected by the second reflecting surface. It is shaped to reflect in the direction of the incident window 23 at 18b.

  Here, since the irradiation window portion 22 and the incident window portion 23 are made independent of each other, the light from the light source 26 is prevented from leaking into the color sensor 27 without passing through the color filter 16. Further, as shown in FIG. 4B, ribs 22a and 23a are provided on the inner surface of the lower cover 21 so as to block between the irradiation window 22 and the incident window 23, respectively. The light from 26 is prevented from leaking into the color sensor 27 without passing through the color filter 16.

  Moreover, the irradiation window part 22 and the incident window part 23 are the structures which have the translucent member in which the surface treatment which diffuses light, such as a satin, was given in the opening part. This is because when a light source having a strong directivity such as an LED is used as the light source 26, a difference in color occurs between the center and the periphery of the light beam emitted from the light source 26. If there is a difference in color characteristics between the center and the periphery of the light beam emitted from the light source 26, the color of the light received by the color sensor 27 changes according to a slight deviation when the filter holder 10 is mounted. Even if it passes through the same color filter, there is a possibility that different discrimination results will be obtained. Therefore, by diffusing light at the irradiation window portion 22 and the incident window portion 23, the color characteristics of the light beam emitted from the light source 26 can be averaged, and filter discrimination can be performed with high accuracy. The surface treatment for diffusing light may be performed on the inner surface side or the outer surface side of the irradiation window portion 22 and the incident window portion 23, or only one of them may have a diffusing action. Also good. Further, the light beam emitted from the light source 26 may be diffused before entering the color sensor 27, and the irradiation window portion 22 and the incident window portion 23 do not have a diffusing action, for example, a prism on the filter holder 10 side. 18 may have a diffusing action. Alternatively, the irradiation window 22 and the incident window 23 do not have a diffusing action, and a diffusion filter is provided between the light source 26 and the irradiation window 22 or between the color sensor 27 and the incident window 23. It may be configured to be inserted.

  The hood 20 of FIGS. 4 and 5 reflects the light that has not been reflected by the reflector 315 in the irradiation direction of the light emitting unit 350 in the irradiation direction of the light emitting unit 350. Therefore, the hood 20 has a shape that becomes larger as the opening in the plane perpendicular to the optical axis of the irradiation light of the light emitting unit 350 approaches the optical system 316 so that the light can be efficiently reflected in the irradiation direction of the light emitting unit 350. ing.

  FIG. 5 is a side view of the light emitting unit 350 with the filter holder 10 attached thereto, and shows a cross-sectional structure of the filter holder 10 including the color filter 16 and the light emitting unit 350. On the upper surface side of the light emitting unit 350, a wide panel 30 that can expand the irradiation range by allowing the irradiation light to pass therethrough, and a catch light sheet 31 that can reflect the irradiation light toward the subject at the time of bounce shooting and obtain a catch light effect. Is stored in a removable manner. Therefore, when the magnetic sensor 25 for discriminating the holder, the light source 26 for discriminating the filter, and the color sensor 27 are arranged on the upper surface side of the light emitting unit 350, it is necessary to arrange them outside the wide panel 30 and the catchlight sheet 31. As a result, the light emitting unit 350 is increased in size. Therefore, the light emitting unit 350 can be reduced in size by arranging the magnetic sensor 25, the light source 26, and the color sensor 27 below the light emitting unit 350 as in the present embodiment.

  Further, since the mechanical switch is not used for holder discrimination and filter discrimination, the detection system of the holder discrimination unit 322 and the detection system of the filter discrimination unit 324 can be arranged in a small space. Therefore, the magnetic sensor 25 and the color sensor 27 can be arranged closer to the irradiation surface side than the case where the mechanical switch is arranged in the space between the lower cover 21 and the hood 20, and the light of the irradiation light of the filter holder 10 can be obtained. The length in the direction parallel to the axis can be suppressed and the size can be reduced.

  The example of the configuration for determining the color characteristics of the color filter 16 based on the result of receiving the light emitted from the light source 26 and transmitted through the color filter 16 by the color sensor 27 has been described. Variations and changes are possible.

  For example, in the above-described embodiment, the prism 18 is used as the light guide unit that guides the light emitted from the light source 26 to the color sensor 27, but a mirror, an optical fiber, or the like may be used instead of the prism 18.

  Further, the light guide unit as described above may be provided on the light emitting unit 350 side. For example, as the filter holder 10 is attached to the light emitting unit 350, the color filter 16 held by the filter holder 10 is between the light guide unit on the light emitting unit 350 side, the irradiation window unit 22, and the incident window unit 23. You may make it insert in.

  The prism 18 serving as a light guide unit guides light from the light source 26 so that the light passes through the color filter 16 twice. However, the light from the light source 26 passes through the color filter 16 a plurality of times, three or more times. It may be a light guide part having a shape for guiding light so as to pass therethrough. As the number of times of transmission through the color filter 16 increases, the change in the color characteristic of the light from the light source 26 increases, so that the accuracy of determining the color characteristic of the color filter is improved. The color characteristics of the filter can be determined.

  The relationship between the number of times of passing through the color filter and the discrimination accuracy will be described with reference to FIG. FIG. 6A is a diagram showing a result of receiving the light emitted from the light source 26 and once transmitted through the color filter 16 by the color sensor 27, and FIG. 6B is a diagram showing the result of the color filter 16 emitted from the light source 26. FIG. 6 is a diagram showing a result of receiving light transmitted twice by a color sensor 27;

  When the color filter 16 is transmitted once, the difference between the chromaticity of the light emitted from the light source 26 and the chromaticity of the light received by the color sensor 27 is small. Therefore, the detection results of the color sensor 27 when the color filters A, B, and C having similar color characteristics are transmitted once are as shown in FIG. 6A, and the difference between the detection results is small. Since the spectral sensitivity characteristic of the color sensor 27 changes depending on the environmental temperature, when associating the detection result of the color sensor 27 with the color characteristic of the color filter 16, the detection result is considered in consideration of the change of the spectral sensitivity characteristic. When included in the predetermined range, it is necessary to correspond to the same color characteristic. When an LED is used as the light source 26, the spectral characteristics of the LED also change depending on the environmental temperature, so that it is necessary to further increase the range of detection results associated with the same color characteristic. Therefore, color filters having similar color characteristics, such as color filters A, B, and C, may have the same color characteristics because the difference in detection results of the color sensor 27 is small when they are transmitted once. .

  On the other hand, as shown in FIG. 6B, when the color filter 16 is transmitted twice, the chromaticity of the light emitted from the light source 26 changes twice, so that the color filters A, B, and C having similar color characteristics. Even so, the difference in the detection results of the color sensor 27 becomes large. For this reason, even if the detection result of the color sensor 27 is given a certain width in association with the color characteristics of the color filter 16 in consideration of changes in the spectral sensitivity characteristics, the color filters A, B, and C are assigned different colors. It is possible to determine the characteristic. It should be noted that the same effect can be obtained even when the number of times of transmission through the color filter 16 is three or more.

  Next, the color characteristic determination process of the color filter 16 will be described with reference to FIGS. FIG. 7 is a diagram illustrating a flowchart of the color characteristic determination process of the color filter 16, and FIG. 8 is a diagram illustrating a range that is regarded as a result of transmission through the same color filter in the detection result of the color sensor 27. FIG. 9 is a diagram showing a table in which the detection result of the color sensor 27 is associated with the color characteristics of the color filter 16. In the present embodiment, a method for determining the color characteristics of the color filter 16 using a table in which the detection results of the color sensor 27 stored in the ROM of the flash microcomputer 310 and the color characteristics of the color filter 16 are associated will be described.

  The flowchart shown in FIG. 7 is started, for example, when the power of the strobe device 300 is turned on or when the strobe microcomputer 310 determines that the filter holder 10 is attached to the light emitting unit 350 of the strobe device 300.

  In step S101, the flash microcomputer 310 performs detection using the color sensor 27 in a state where the light source 26 is not emitting light. The color sensor 27 outputs a signal corresponding to the three primary colors R, G, and B as a detection result (light reception result), and the detection result when the light source 26 is not emitting is (rn, gn, bn). To do.

  In step S <b> 102, the flash microcomputer 310 causes the light source 26 to emit light, and causes the light transmitted through the color filter 16 to enter the color sensor 27. In step S103, the stroboscopic microcomputer 310 uses the color sensor 27 to perform detection in a state where the light source 26 is caused to emit light. A detection result in a state where the light source 26 emits light is (rs, gs, bs).

In step S104, the stroboscopic microcomputer 310 performs an operation of removing (rn, gn, bn), which is a detection result when the light source 26 is not lit, from the detection result when the light source 26 is lit as a noise component. Do. If the result of removing (rn, gn, bn) from (rs, gs, bs) is (rc, gc, bc), rc = rs−rn (Equation 1 to Equation 3), respectively. 1)
gc = gs-gn (2)
bc = bs-bn (3)
It becomes.

  In step S105, the stroboscopic microcomputer 310 calculates information on the color characteristics of the light transmitted through the color filter 16 based on the calculation result (rc, gc, bc) obtained in step S104, using Expression (4). .

  By appropriately selecting the matrix coefficients M11 to M33 in the equation (4), the detection result of the color sensor 27 is a value Br that represents the brightness of light and a value Cx that represents the chromaticity of the received light in two axes. It can be converted to Cy. Hereinafter, the values Cx and Cy representing the chromaticity of light with two axes will be referred to as chromaticity information.

  In steps S106 to S112, the flash microcomputer 310 determines the color characteristics of the color filter 16 based on the chromaticity information obtained in step S105 and the table shown in FIG.

  In step S106, the flash microcomputer 310 determines whether or not the chromaticity information obtained in step S105 is included in the first range shown in FIG. When the chromaticity information obtained in step S105 is included in the first range, the process proceeds to step S107, and the stroboscopic microcomputer 310 determines the color temperature H of the color filter 16 as 5000K based on the table of FIG. . The color temperature H shown in the table of FIG. 9 represents the color temperature of light emitted from the discharge tube 307 and transmitted once through the color filter 16, and hereinafter, the color temperature H emitted from the discharge tube 307 is 1 The color temperature H of the transmitted light is expressed as the color temperature H of the color filter 16. That is, the color filter having the color temperature H is a color filter having a color characteristic that converts the light emitted from the discharge tube 307 into light having the color temperature H by transmitting the light once.

  If the chromaticity information obtained in step S105 is not included in the first range, the process proceeds to step S108, and the flash microcomputer 310 determines that the chromaticity information obtained in step S105 is within the second range shown in FIG. Judge whether it is included. When the chromaticity information obtained in step S105 is included in the second range, the process proceeds to step S109, and the flash microcomputer 310 determines the color temperature H of the color filter 16 as 3500K based on the table of FIG. .

  If the chromaticity information obtained in step S105 is not included in the second range, the process proceeds to step S110, and the flash microcomputer 310 causes the chromaticity information obtained in step S105 to fall within the third range shown in FIG. Judge whether it is included. When the chromaticity information obtained in step S105 is included in the third range, the process proceeds to step S111, and the stroboscopic microcomputer 310 determines the color temperature H of the color filter 16 as 2000K based on the table of FIG. .

  If the chromaticity information obtained in step S105 is not included in the third range, the flash microcomputer 310 indicates that the detection result of the color sensor 27 is not accurate, or the light from the light source 26 is transmitted through the color filter 16. It is assumed that no discrimination is possible.

  Information regarding the color characteristics of the color filter 16 obtained in steps S106 to S112 is displayed on the display unit 321. Alternatively, it is transmitted from the flash microcomputer 310 to the camera microcomputer 101 via the signal line SC. The camera microcomputer 101 performs white balance adjustment suitable for the irradiation light of the flash device 300 by performing white balance correction based on the information regarding the color characteristics of the color filter 16 received from the flash microcomputer 310. The information regarding the color characteristics of the color filter 16 transmitted from the flash microcomputer 310 to the camera microcomputer 101 may be the color temperature H of the light emitted from the discharge tube 307 and transmitted once through the color filter 16 or the color characteristics of the color filter 16. .

  As described above, by determining the color characteristics of the color filter 16 based on the result of receiving the light emitted from the light source 26 and transmitted through the color filter 16 by the color sensor 27, regardless of the mounting direction of the color filter 16, Color characteristics can be accurately determined.

  Although the accuracy of determining the color characteristics of the color filter 16 is improved by removing the noise component from the detection result of the color sensor 27 in the state where the light source 26 emits light, the noise component may not be removed. It is possible to determine the color characteristics of the color filter 16.

(Second Embodiment)
The configuration of the imaging system according to this embodiment is the same as that of the first embodiment, but the method for determining the color characteristics of the color filter 16 is different from that of the first embodiment. The color characteristic discrimination processing of the color filter 16 in the present embodiment will be described with reference to FIGS. FIG. 10 is a diagram showing a flowchart of the color characteristic discrimination processing of the color filter 16, and FIG. 11 is a diagram showing the spectral characteristics of the light source 26 and the discharge tube 307 and the spectral sensitivity characteristics of the color sensor 27.

  The flowchart shown in FIG. 10 is started, for example, when the power of the strobe device 300 is turned on or when the strobe microcomputer 310 determines that the filter holder 10 is attached to the light emitting unit 350.

  Steps S201 to S204 perform the same processing as steps S101 to S104, respectively, and thus detailed description thereof is omitted.

In step S205, the stroboscopic microcomputer 310 performs a temperature correction process on the calculation result (rc, gc, bc) obtained in step S104. This is because, as described above, the spectral sensitivity characteristic of the color sensor 27 and the spectral characteristic of the light source 26 change depending on the environmental temperature.
(Rp, gp, bp), which is a result of performing the temperature correction processing on (rc, gc, bc), is as follows from the equations (5) to (7).
rp = rc × LR (t) × CR (t) (5)
gp = gc × LG (t) × CG (t) (6)
bp = bc × LB (t) × CB (t) (7)

  Here, t is the environmental temperature, and (LR, LG, LB) is a temperature correction coefficient for compensating for the change in the spectral characteristics of the light source 26 and changes according to the environmental temperature. Further, (CR, CG, CB) is a temperature correction coefficient for compensating for the change in the spectral sensitivity characteristic of the color sensor 27 and changes according to the environmental temperature. These coefficients are stored in the ROM or the like of the flash microcomputer 310 as a table in which the environmental temperature and the coefficients are associated with each other. By performing the correction processing for the above temperature change, (rp, gp, bp) becomes a value corresponding to (rc, gc, bc) at a predetermined reference temperature.

  The ambient temperature may be measured by providing a temperature sensor in the strobe device 300, or measured by a temperature sensor provided in the camera body 100 connected to the strobe device 300 and receiving the measurement result from the camera body 100. You may do it.

  Further, since the light source 26 may change its spectral characteristics due to its own heat generation due to light emission, the temperature sensor for determining the temperature correction coefficient of the light source 26 and the temperature for determining the temperature correction coefficient of the color sensor 27. You may make it provide a sensor, respectively. In that case, if a plurality of temperature sensors are provided in the vicinity of the light source 26 and the color sensor 27, respectively, a more appropriate temperature correction coefficient can be determined. Alternatively, the environmental temperature for determining the temperature correction coefficient of the light source 26 and the environmental temperature for determining the temperature correction coefficient of the color sensor 27 may be measured at different timings.

  In step S206, the flash microcomputer 310 reads reference values (r0, g0, b0) stored in advance in a ROM or the like. The reference values (r0, g0, b0) are values obtained by performing Steps S201 to S204 without mounting the color filter 16 at a predetermined reference temperature.

In step S207, the stroboscopic microcomputer 310 calculates a value when the number of times the color filter 16 has been transmitted is 1 based on the correction result (rp, gp, bp) obtained in step S205 (number of transmissions). correction). The values (rw, gw, bw) when the number of times the color filter 16 is transmitted once in the configuration in which the color filter 16 is transmitted n times are as follows from the equations (8) to (10), respectively. Become.
rw = r0− (r0−rp) / n (8)
gw = g0− (g0−gp) / n (9)
bw = b0− (b0−bp) / n (10)
Note that this step may be omitted as long as the color filter 16 is transmitted once.

  In step S208, the stroboscopic microcomputer 310 receives values (rx, gx) when the color sensor 27 receives light emitted from the discharge tube 307 and transmitted once through the color filter 16 based on the values (rw, gw, bw). , Bx) (spectral characteristic correction). As shown in FIG. 11, the spectral characteristics of the light source 26 and the spectral characteristics of the discharge tube 307 are different. In order to determine the color characteristics of the irradiation light of the strobe device 300 after passing through the color filter 16, the light source 26 It is necessary to consider the difference between the spectral characteristics of the discharge tube 307 and the spectral characteristics of the discharge tube 307.

  When the spectral coefficient of the discharge tube 307 is Xe, the spectral coefficient of the light source 26 is WL, the spectral coefficient of the color sensor 27 is the three primary colors (CsR, CsG, CsB), and the wavelength is λ, (rx, gx, bx) 11) to (13) are as follows.

  In step S209, the stroboscopic microcomputer 310 calculates information on the color characteristics of the color filter 16 using the equation (14) based on the calculation result (rx, gx, bx) obtained in step S208 (color temperature calculation). ).

  By appropriately selecting the matrix coefficients m11 to m33, the color tristimulus values (rx, gx, bx) based on the information (rx, gx, bx) on the color characteristics of the light emitted from the discharge tube 307 and transmitted once through the color filter 16 X, Y, Z) can be calculated. The color characteristic of the color filter 16 can be determined by calculating the color temperature H of the color filter 16 based on the calculated tristimulus values (X, Y, Z). As a method for calculating the color temperature H from the tristimulus values (X, Y, Z), a known method may be used, and details thereof are omitted.

  As described above, by determining the color characteristics of the color filter 16 based on the result of receiving the light emitted from the light source 26 and transmitted through the color filter 16 by the color sensor 27, regardless of the mounting direction of the color filter 16, Color characteristics can be accurately determined.

  In addition, since the color characteristics of the color filter are determined by calculation without using a table in which the detection result of the color sensor 27 and the color characteristics of the color filter are associated with each other, the color filter of the color filter is finer than when the table is used. Color characteristics can be determined.

  In the above-described determination processing, correction is performed on the values obtained in the previous processing in the order of noise correction, temperature correction, transmission count correction, and spectral characteristic correction, but based on the detection result of the color sensor 27. It can be said that each correction is performed on the information.

  Further, depending on various conditions such as the environmental temperature, the number of transmissions, and the spectral characteristics of the light source, a part of each correction of the determination process may be omitted, and all the correction processes may not be performed.

(Third embodiment)
In the first and second embodiments, the configuration for determining the color characteristics of the color filter 16 using the light source 26 and the color sensor 27 that are white LEDs has been described. However, in the present embodiment, the first and second embodiments are described. The configuration of the light source 26 and the color sensor 27 is different from that of the embodiment. Specifically, an RGB LED having three primary colors of a red LED, a green LED, and a blue LED is used as the light source 26 instead of the white LED, and a photodiode is used as the light receiving unit instead of the color sensor 27.

  The configuration of the imaging system according to the present embodiment is different from the configuration of the imaging system according to the first and second embodiments only in the light source 26 and the color sensor 27 as described above, and a detailed description of the configuration is omitted. Hereinafter, RGB LEDs 26 ′ and photodiodes 27 ′ are associated with the light source 26 and the color sensor 27 of the first and second embodiments, respectively.

  The color characteristic discrimination processing of the color filter 16 in the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart of the color characteristic determination process of the color filter 16. After step S308, the process proceeds to step S105 in FIG. 7 or step S205 in FIG.

  In step S301, the stroboscopic microcomputer 310 uses the photodiode 27 'to perform detection in a state where the RGB LED 26' is not emitting light. The detection result of the photodiode 27 ′ at this time is (An).

  In S302, the stroboscopic microcomputer 310 causes the red LED of the RGB LED 26 'to emit light and causes the light transmitted through the color filter 16 to enter the photodiode 27'. In step S303, the stroboscopic microcomputer 310 performs detection in a state where the red LED emits light using the photodiode 27 '. The detection result when the red LED is caused to emit light is (rs ′).

  In S304, the stroboscopic microcomputer 310 causes the green LED of the RGB LED 26 'to emit light and makes the light transmitted through the color filter 16 enter the photodiode 27'. In step S305, the stroboscopic microcomputer 310 performs detection in a state where the green LED emits light using the photodiode 27 '. The detection result in a state where the green LED emits light is (gs ′).

  In S306, the stroboscopic microcomputer 310 causes the blue LED of the RGB LED 26 'to emit light and causes the light transmitted through the color filter 16 to enter the photodiode 27'. In step S307, the stroboscopic microcomputer 310 performs detection in a state where the blue LED emits light using the photodiode 27 '. The detection result when the blue LED emits light is (bs ′).

In step S308, the stroboscopic microcomputer 310 performs an operation of removing (An), which is a detection result when the RGBLED 26 'is not emitting light, from the detection result when the RGBLED 26' is emitting, using (An) as a noise component. If the result of removing (An) from each of (rs ′, gs ′, bs ′) is (rc ′, gc ′, bc ′), rc ′ = rs ′ from Expressions (15) to (17), respectively. -An (15)
gc ′ = gs′−An (16)
bc ′ = bs′−An (17)
It becomes.

  Thereafter, the process proceeds to step S105 in FIG. 7 or step S205 in FIG. 10, and (rc ′, gc ′, bc ′) is used instead of (rc, gc, bc) in the first and second embodiments. The color characteristics of the color filter 16 are discriminated.

  As described above, also in this embodiment, the color characteristics can be accurately determined regardless of the mounting direction of the color filter 16 as in the first and second embodiments.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  For example, in the above-described embodiment, the configuration using the discharge tube 307 as the main light source of the strobe device 300 has been described. However, the main light source is configured using a light source of the same type as the light source for color filter discrimination, for example, an LED. It doesn't matter.

  In the above embodiment, the configuration in which the color filter 16 is attached to the filter holder 10 and the filter holder 10 is attached to the light emitting unit 350 has been described. However, if the light emitting unit 350 has a color filter holding unit, There may be no filter holder. In that case, the light guide part like the prism 18 in the above embodiment is provided on the light emitting part 350 side, and the color filter 16 is inserted between the light guide part and the irradiation window part 22 and the incident window part 23. It is desirable that the color filter be held in

  In addition, the color filter color characteristic determination processing of the present invention is not limited to the stroboscopic device 300 that can be attached to and detached from the imaging device, but the color filter can be attached to the front of the irradiation unit of the stroboscope built in the imaging device. Applicable.

DESCRIPTION OF SYMBOLS 10 Filter holder 16 Color filter 17 Magnet 18 Prism 24 Board | substrate 25 Magnetic sensor 26 Light source 27 Color sensor 29 Protrusion part 310 Strobe microcomputer 322 Holder discrimination | determination part 324 Filter discrimination | determination part

Claims (11)

An illumination device capable of attaching an optical accessory that changes the color characteristic of transmitted light to the front of the light emitting unit,
A light source;
A light receiving means;
Based on a light reception result of the light received from the light source and transmitted through the optical accessory by the light receiving means and a light reception result of the ambient light received by the light receiving means when the light source is not emitting light . Discrimination means for discriminating color characteristics;
A lighting device comprising:   The discriminating means calculates the information on the color characteristics of light emitted from the light source and transmitted through the optical accessory based on the light reception result of the light receiving means, and discriminates the color characteristics of the optical accessory. Item 2. The lighting device according to Item 1. The illumination device is configured to receive light emitted from the light source and transmitted through the optical accessory a plurality of times by the light receiving means,
The discriminating unit corrects information based on a light reception result obtained by the light receiving unit receiving light emitted from the light source and transmitted through the optical accessory based on the number of times the light emitted from the light source passes through the optical accessory. The lighting device according to claim 2, wherein information relating to color characteristics of light transmitted through the optical accessory is calculated. The determination means corresponds to a case where the light receiving means receives the light emitted from the light source and transmitted once through the optical accessory based on the number of times the light emitted from the light source passes through the optical accessory. And correcting information based on a light reception result obtained by receiving the light emitted from the light source and transmitted through the optical accessory by the light receiving means, and calculating information on color characteristics of the light transmitted through the optical accessory. The lighting device according to claim 3. Having a temperature sensor to measure the temperature,
5. The discriminating means corrects information based on a light reception result based on a temperature measured by the temperature sensor, and calculates information on color characteristics of light transmitted through the optical accessory. The illumination device according to any one of the above.   The discriminating unit corrects information based on a light reception result of the light receiving unit based on the temperature measured by the temperature sensor and compensates for a temperature change of the spectral sensitivity characteristic of the light receiving unit and transmits the optical accessory. The lighting device according to claim 5, wherein information relating to the color characteristics of the emitted light is calculated. The discriminating means receives the light emitted from the light source and transmitted through the optical accessory so as to compensate for the temperature change of the spectral characteristics of the light source based on the temperature measured by the temperature sensor. The lighting device according to claim 5 or 6, wherein information on a color characteristic of light transmitted through the optical accessory is calculated by correcting information based on the result.   The discriminating unit corrects information based on the light reception result of the light receiving unit based on the spectral characteristic of the main light source irradiated with light from the light emitting unit and the spectral characteristic of the light source, and passes through the optical accessory The lighting device according to claim 2, wherein information relating to the color characteristics of the lighting device is calculated. Storage means for preliminarily storing information relating the color characteristics of light emitted from the light source and transmitted through the optical accessory and the color characteristics of the optical accessory;
The discriminating means is based on the information on the color characteristics of the light emitted from the light source and transmitted through the optical accessory calculated based on the light reception result of the light receiving means and the information stored in the storage means. The lighting device according to claim 2, wherein color characteristics of the lighting device are discriminated. The discriminating unit removes the light reception result of the ambient light received by the light receiving unit when the light source is not emitting from the light reception result of the light received from the light source and transmitted through the optical accessory by the light receiving unit . The lighting device according to any one of claims 2 to 9, wherein information on a color characteristic of light transmitted through the optical accessory is calculated based on a result . An illuminating device capable of attaching an optical accessory that changes the color of transmitted light to the front of the light emitting unit;
A light source;
A light receiving means;
A light guide that guides the light emitted from the light source in the direction of the light receiving means so that the light emitted from the light source passes through an optical accessory attached to the lighting device and is received by the light receiving means; ,
Discriminating means for discriminating the color of the optical accessory based on the result of receiving the light emitted from the light source by the light receiving means and the result of receiving the ambient light by the light receiving means when the light source is not emitting light. When,
Imaging means for imaging a subject irradiated with irradiation light of the illumination device;
White balance correction means for correcting the white balance of the output of the imaging means based on the output of the determination means;
An imaging system comprising:

Images