JP2008152275A - Surface sequential color image imaging method and digital camera with surface sequential emission strobe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface sequential color image imaging method capable of obtaining a high-quality color image using a monochromatic imaging device having no color filter, and to provide a digital camera with a surface sequential emission strobe. <P>SOLUTION: With a single shutter releasing operation, R, G and B strobe light beams are emitted three times in a prescribed sequence from an R light emitting part 52, a G light emitting part 53 and a B light emitting part 54 of the surface sequential emission strobe 50. Image data corresponding to respective R, G and B color strobe light beams are obtained by an imaging part having a monochromatic CCD 20 having no color filter, respectively. Consequently, a color still image of higher resolution can be obtained as compared with a color imaging means having the same number of pixels. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for capturing a frame sequential color image and a digital camera with a frame sequential light emission strobe, and more particularly to a method for capturing a frame sequential color image and a digital camera with a frame sequential light emission strobe capable of obtaining a high quality image.

  Conventional digital cameras use color image sensors with color filters such as R, G, B (red, green, blue) or Mg, Cy, Ye (magenta, cyan, yellow) attached, and strobe light. As a photographer using a white light source such as a xenon tube.

In recent years, there has been proposed a strobe device that uses R, G, and B light emitting diodes (LEDs) as a strobe light source, changes the color temperature of strobe light, and can emit strobe light with a slow shutter (Patent Document 1). ).
JP 2002-116481 A

  By the way, the luminance signal generated based on the R, G, B signals output from the color image sensor is R: G: B = 0.3: 0 so as to match the sensitivity characteristic with respect to the brightness of human eyes. .6: 0.1, the SN of B is poor, and there is a problem that noise in dark portions of B color increases when an image is printed based on captured image data.

  Further, since the color image sensor generates R, G, and B signals on a certain pixel by interpolating an insufficient color signal from surrounding pixels, the color image sensor is more than a monochrome image sensor having the same number of pixels. There is also a problem that the resolution is low. In order to solve this problem, some have three-plate type image pickup devices for R, G, and B. In this case, however, the number of image pickup devices, installation space, and the like increase.

  The present invention has been made in view of such circumstances, and uses a monochrome imaging element without a color filter, and provides a frame sequential color image imaging method and a plane sequential light emission strobe capable of obtaining a high quality color image. The purpose is to provide a digital camera.

  In order to achieve the above object, according to the first aspect of the present invention, R, G, and B strobe lights are sequentially emitted in a predetermined order from a surface sequential light emission strobe, and black and white imaging is performed in synchronization with each light emission of the strobe light. A frame sequential color image capturing method in which the image capturing unit is operated to acquire R, G, B frame sequential image data from the image capturing unit, and the flash emission amount is determined when the shutter release button is half-pressed. Capturing information for performing, capturing the color temperature of the object scene from the temperature sensor when the shutter release button is half-pressed, or capturing the color temperature set manually, and the captured information and A step of setting R, G, and B strobe emission amounts emitted from the surface-sequential emission strobe based on the color temperature so that light having the same color temperature is emitted. Steps for setting the light emission amounts of the R, G, and B strobe lights that are sequentially emitted, and when the shutter release button is fully pressed, the frame sequential light emission strobe is synchronized with the full press of the shutter release button. A step of emitting the first strobe light among the R, G, and B strobe lights in the set amount of strobe light; and after the first strobe light has been emitted, from the imaging unit When the image data corresponding to the strobe light is captured and stored in the temporary storage device, and when the image data corresponding to the first strobe light is captured, the R, G, B A step of causing the second strobe light among the strobe lights to be emitted by the set strobe light amount; After the end of the emission of the strobe light, the step of taking in the image data corresponding to the second strobe light from the imaging means and storing it in the temporary storage device, and the end of the taking in of the image data corresponding to the second strobe light A step of emitting the third strobe light among the R, G, and B strobe lights from the surface sequential light emission strobe light by the set strobe light amount, and after the third strobe light emission ends. Capturing image data corresponding to the third strobe light from the imaging means and storing the image data in a temporary storage device.

  That is, R, G, B strobe light is emitted three times in a predetermined order from a surface sequential light emission strobe with one shutter release, and an image corresponding to R, G, B strobe light by a monochrome imaging means. Data is fetched three times and each is stored in a temporary storage device. The R, G, and B strobe lights sequentially emitted from the surface sequential light emission strobe light include information for determining the amount of strobe light emitted when the shutter release button is half-pressed, and the object field captured from the temperature sensor. The R, G, and B strobe emission amounts are set so that the strobe light having the same color temperature is emitted based on the color temperature or the color temperature set manually. As a result, the color temperature of the entire three times of light emission can be set to the same color temperature as the color temperature of the object scene or the color temperature set manually. The frame sequential R, G, B image data imaged in synchronism with the light emission of the frame sequential light emission strobe is appropriately combined and used for printing or reproduction. In addition, a high-resolution image can be obtained as compared with a color imaging means having the same number of pixels, and printing with good image quality can be obtained when printing a color image.

  According to a second aspect of the present invention, in the frame sequential color image capturing method according to the first aspect, the method further includes the step of recording the R, G, and B image data stored in the temporary storage device respectively on a recording medium. It is characterized by that.

  According to a third aspect of the present invention, in the frame sequential color image capturing method according to the first aspect, R, G, and B image data stored in the temporary storage device are combined to create one image data. And a step of recording the created image data on a recording medium.

  According to a fourth aspect of the present invention, there is provided a digital camera equipped with a field sequential light emission strobe. A field sequential light emission strobe that emits R, G, and B strobe light in a field sequential manner, a black and white imaging unit, and a surface sequential light emission from the field sequential light emission strobe. Means for taking in information for determining the amount of R, G, B strobe light to be emitted, means for manually setting the color temperature, and R, G, B for emitting light sequentially in the frame sequential light emission strobe. Adjusting means for respectively adjusting the light emission amount of the strobe light so that light of the same color temperature is emitted based on the information for determining the light emission amount of the captured strobe light and the set color temperature Adjusting means for adjusting the amount of flash light emitted from each light emitting section that emits light in frame order, and control means for performing imaging three times with one shutter release, the adjusting means The R, G, and B strobe lights whose light emission amounts are adjusted are sequentially emitted in a predetermined order from the frame sequential light emission strobe, and the imaging unit is synchronized with the R, G, and B strobe lights. The image capturing operation is performed to acquire R, G, and B frame sequential image data from the imaging unit, and the acquired frame sequential image data is stored in a temporary storage device and then recorded on a recording medium. And a recording means.

  According to a fifth aspect of the present invention, there is provided a digital camera equipped with a field sequential light emission strobe. The field sequential light emission strobe that emits R, G, B strobe light in the field sequential order, the monochrome image pickup means, and the surface sequential light emission strobe light. Means for capturing information for determining the amount of R, G, B strobe light to be emitted; a color temperature sensor for detecting the color temperature of the object field; Adjusting means for respectively adjusting the light emission amounts of G and B strobe light, the information for determining the light emission amount of the captured strobe light and the color temperature set to the color temperature detected by the color temperature sensor And adjusting means for adjusting the amount of stroboscopic light emitted from each light emitting unit that emits light in the order of frames so that light having the same color temperature is emitted, and one shutter release to perform imaging three times. Control means for causing the R, G, and B strobe lights, the light emission amounts of which have been adjusted by the adjusting means, to be sequentially emitted in a predetermined order from the frame sequential light emission strobe, and the R, G, and B strobe lights; Control means for acquiring the R, G, B frame sequential image data from the imaging unit by performing an imaging operation of the imaging unit in synchronization with the light, and storing the acquired frame sequential image data in the temporary storage device. Thereafter, a recording means for recording on a recording medium is provided.

  According to the inventions according to claims 4 and 5, the R, G, B strobe light is emitted three times in a predetermined order from the surface sequential light emission strobe with one shutter release, and R, G, Image data corresponding to the strobe light of each color B is captured three times and stored in a temporary storage device. The R, G, and B strobe lights sequentially emitted from the surface sequential strobe light are information for determining the light emission amount of the R, G, and B strobe lights and the object field captured from the temperature sensor. The R, G, and B strobe emission amounts are set so that the strobe light having the same color temperature is emitted based on the color temperature or the manually set color temperature. As a result, the color temperature of the entire three times of light emission can be set to the same color temperature as the color temperature of the object scene or the color temperature set manually. The frame sequential R, G, B image data imaged in synchronism with the light emission of the frame sequential light emission strobe is appropriately combined and used for printing or reproduction. In addition, a high-resolution image can be obtained as compared with a color imaging means having the same number of pixels, and printing with good image quality can be obtained when printing a color image. The frame sequential light emission strobe may be externally attached to the digital camera or may be built in.

  6. The digital camera with a frame sequential light emission strobe according to claim 4, further comprising recording means for recording the acquired frame sequential image data of R, G, B on a recording medium, respectively. It is characterized by that.

  According to a seventh aspect of the present invention, in the digital camera with a frame sequential light emission strobe according to the fourth or fifth aspect, the acquired frame sequential image data of R, G, B is synthesized to create one image data. The image processing apparatus includes a combining unit and a recording unit that records the created image data on a recording medium.

  According to the present invention, it is possible to obtain a high-quality color image by using a black and white image pickup element without a color filter, and in particular, it is possible to perform three-time sequential imaging by one shutter release, Or a three-sequential color image (still image) illuminated with strobe light having the same color temperature (the color temperature of the entire three times of light emission) as the color temperature set manually or the color temperature set manually.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a frame sequential color image capturing method and a frame sequential light emitting strobe digital camera according to the present invention will be described in detail below with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of a digital camera with a frame sequential light emission strobe according to the present invention.

  This digital camera with a frame sequential light emission strobe performs imaging while being fixed to a tripod. The digital camera has a monochrome image pickup device (CCD) 20 without a color filter and an external or built-in surface sequential light emission flash 50. If the shutter button is pressed, R, G, B strobe lights are emitted sequentially from the surface sequential light emission strobe 50, and images are taken for each color emission, and imaged three times with one shutter release. I do. The overall operation of the camera is centrally controlled by a central processing unit (CPU) 12.

  The operation unit 14 of the digital camera includes a power switch, a shutter button, a mode switching switch for switching between a shooting mode and a playback mode, a multi-function cross key for outputting various command signals such as zoom and frame advance. Various operation signals from the operation unit 14 are applied to the CPU 12.

  As described above, when the shutter button is pressed, the CPU 12 sequentially emits the R, G, and B strobe lights from the surface sequential light emission strobe 50 and controls the operation of the CCD 20 and the like for each color light emission for three sheets. Image data acquisition control is performed.

  That is, when a strobe light of a certain color among R, G, and B is emitted from the surface-sequential light-emitting strobe 50, the reflected light of the strobe light from the subject is a lens optical system 16 including a focus lens and an aperture 18. Then, an image is formed on the light receiving surface of the CCD 20. The signal charge accumulated in the CCD 20 is sequentially read out as a voltage signal corresponding to the signal charge by a transfer pulse applied from the CCD driver 22. The CCD 20 has a so-called electronic shutter function that controls the charge accumulation time (shutter speed) of each photosensor according to the timing of the shutter gate pulse.

  The voltage signal sequentially read from the CCD 20 is applied to the analog processing unit 24. The analog processing unit 24 includes a signal processing circuit such as a sampling hold circuit that performs correlated double sampling (CDS) processing, a gain adjustment circuit, and the like. The analog processed signal is converted into a digital signal ( (Hereinafter referred to as “CCDRAW data”) and then stored in a temporary storage device 28 such as an SDRAM.

  The temporary storage device 28 has a storage capacity capable of temporarily storing, for example, three or more pieces of CCD RAW data. The timing generator (TG) 30 provides timing signals to the CCD driver 22, the analog processing unit 24, and the A / D converter 26 in accordance with instructions from the CPU 12, and the circuits are synchronized by this timing signal. ing. The ROM 32 stores programs and adjustment values in advance, and these programs and adjustment values are read as appropriate.

  When the CCD RAW data for three pieces of R, G, and B is stored in the temporary storage device 28 by three imaging operations, the signal processing unit 34 performs white balance on the R, G, and B CCD RAW data. Correction, gamma correction, luminance data Y and chrominance data Cr and Cb generation processing (YC processing), contour enhancement processing, and the like are sequentially performed as signal processing. The image data processed by the signal processing unit 34 is encoded by a video encoder 38 and output to a liquid crystal monitor (LCD) 40 provided on the back of the camera, whereby a subject image is displayed on the display screen of the LCD 40. Is done.

  The CCD RAW data stored in the temporary storage device 28 is rewritten with the image data (YC data) processed by the signal processing unit 34, and the YC data stored in the temporary storage device 28 is sent to the compression / decompression processing unit 36. The data is output, subjected to a predetermined compression process such as JPEG (joint photographic experts group), and stored in the temporary storage device 28 again. The media controller 42 records the compressed data temporarily stored in the temporary storage device 28 on the memory card 10 via the card interface 44.

  Next, the surface sequential light emission strobe 50 will be described.

  The frame sequential light emission strobe 50 is mainly composed of a light emission control unit 51, an R light emission unit 52, a G light emission unit 53, and a B light emission unit 54.

  The light emission control unit 51 emits R, G, and B strobe lights in a predetermined order from the R light emission unit 52, the G light emission unit 53, and the B light emission unit 54 according to a command from the CPU 12, and for each of R, G, and B, respectively. When it is detected by the light control sensor or the like in the light emitting unit that the light emission amount set in (2) has reached the specified value, the light emission is stopped.

  In addition, as the R light emission part 52, the G light emission part 53, and the B light emission part 54, the thing provided with the color filter of R, G, B on the front surface of the light emitting diode of R, G, B, or a xenon tube, or It is conceivable to sequentially move R, G, B color filters to the front of one white strobe light source.

  Next, the operation of the digital camera with the surface sequential light emission strobe having the above-described configuration will be described with reference to the timing chart shown in FIG.

  First, upon receiving a strobe on signal (FIG. 2A) for performing strobe shooting from the CPU 12, the light emission control unit 51 starts charging a main capacitor (not shown). The main capacitor may be provided for each of the R light emitting unit 52, the G light emitting unit 53, and the B light emitting unit 54, and each of the R light emitting unit 52, the G light emitting unit 53, and the B light emitting unit 54 has electric energy. One main capacitor for supplying

  When charging of the main capacitor is completed, the charging operation is stopped (FIGS. 2B and 2C).

  Thereafter, when the shutter release button is half-pressed, the standby state is set (FIG. 2D), and the light emission control unit 51 takes in information for determining the flash light emission amount such as a guide number from the CPU 12. When the color temperature setting is in the auto mode, the color temperature of the object field is read from a color temperature sensor (not shown), and in the manual mode, the color temperature set manually is read (FIG. 2E). ).

  The light emission control unit 51 determines the R, G, and B strobe light emission amounts based on the captured information, and sets the reference values for adjusting the light emission amount to obtain the strobe light emission amounts, respectively. The light is output to the light emitting unit 53 and the B light emitting unit 54. The ratio of the light emission amounts of the R light emission unit 52, the G light emission unit 53, and the B light emission unit 54 is set so that light having the same color temperature is emitted based on the color temperature of the object scene (FIG. 2). (F)).

  Next, when the shutter release button is fully pressed and the shutter is opened, a light emission signal synchronized with the opening of the shutter is input, and first, R strobe light with a predetermined light emission amount is emitted from the R light emitting unit 52 (FIG. 2). (G)). After completion of the strobe light emission, R CCD RAW data is taken in via the CCD 20, the analog processing unit 24 and the A / D converter 26 (FIG. 2F) and stored in the temporary storage device 28.

  Subsequently, when the capture of the R CCD RAW data is completed, the G light emission unit 53 emits the G strobe light (FIG. 2G), and the G CCD RAW data is captured after the completion of the strobe light emission (FIG. 2F). ), When the capture of the CCD RAW data of G is completed, the B light emission unit 54 emits the B strobe light (FIG. 2G), and after the completion of the strobe light emission, the B CCD RAW data is captured (FIG. 2F). .

  As described above, when R, G, and B frame sequential CCD RAW data is captured and stored in the temporary storage device 28 by three imaging operations, the signal processing unit 34 thereafter performs R, G, and R as described above. , A process for synthesizing one color image from the CCD RAW data of B is performed and recorded in the memory card 10.

  A color image can be printed by displaying the color image on a monitor based on the combined color image recorded on the memory card 10 or outputting the color image to a printer.

  Note that three image data of R, G, and B may be recorded in the memory card 10, and image data for color display is created from these three image data, or an image for printing. Data may be created.

1 is a block diagram showing an embodiment of a digital camera with a field sequential light emission strobe according to the present invention. Timing chart used for explaining the operation of the digital camera with a field sequential light emission strobe according to the present invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Memory card, 12 ... Central processing unit (CPU), 14 ... Operation part, 16 ... Lens optical system, 20 ... Image sensor (CCD), 24 ... Analog processing part, 26 ... A / D converter, 28 ... Temporary Storage device 34 ... Signal processing unit 36 ... Compression / decompression processing unit 42 ... Media controller 44 ... Card interface 50 ... Sequential light emission strobe 51 ... Light emission control unit 52 ... R light emission unit 53 ... G light emission unit 54 B light emitting part

Claims (7)

R, G, B strobe lights are sequentially emitted in a predetermined order from the surface sequential light emission strobe, and the black and white image pickup means is operated in synchronization with each light emission of the strobe light, and the image pickup means R, G, B A frame sequential color image capturing method for acquiring the frame sequential image data of
When the shutter release button is half-pressed, a step for capturing information for determining the flash emission amount,
When the shutter release button is half-pressed, the step of taking in the color temperature of the object scene from the temperature sensor, or taking in the color temperature set manually,
A step of setting R, G, and B strobe emission amounts emitted from the frame sequential light emission strobe based on the captured information and color temperature, wherein the light emission is performed in a frame sequential manner so that light of the same color temperature is emitted. Setting each of the R, G, and B strobe light emission levels;
When the shutter release button is fully pressed, the strobe light having the first light emission order among the R, G, and B strobe lights from the frame sequential light emission strobe is synchronized with the full press of the shutter release button. A step to fire only the set flash output,
Capturing image data corresponding to the first strobe light from the imaging means after the end of the emission of the first strobe light, and storing the image data in a temporary storage device;
When the capture of the image data corresponding to the first strobe light is finished, the set strobe light emission amount is set to the second strobe light among the R, G and B strobe lights from the frame sequential light emission strobe. Only to emit light,
Capturing image data corresponding to the second strobe light from the imaging means after the end of the second strobe light emission, and storing the image data in a temporary storage device;
When the capture of image data corresponding to the second strobe light is completed, the set strobe emission amount is set to the third strobe light among the R, G, B strobe lights from the frame sequential light emission strobe. Only to emit light,
Capturing image data corresponding to the third strobe light from the imaging means after the end of the emission of the third strobe light, and storing the image data in a temporary storage device;
A method of imaging a frame sequential color image.   2. The frame sequential color image capturing method according to claim 1, further comprising a step of recording R, G, and B image data stored in the temporary storage device on a recording medium. Combining R, G, B image data stored in the temporary storage device to create one image data;
Recording the created image data on a recording medium;
The method of claim 1, further comprising: a field sequential color image. A field sequential strobe that emits R, G, B strobe light in a field sequential manner;
Black and white imaging means;
Means for fetching information for determining the amount of R, G, B strobe light emitted from the surface sequential light emission strobe in a surface sequential manner;
Means to set the color temperature manually,
Adjusting means for adjusting the light emission amounts of R, G, and B strobe lights that are emitted in a field sequential manner from the frame sequential light emission strobe, the information for determining the light emission amount of the captured strobe light and the setting Adjusting means for adjusting the amount of strobe light emitted from each light emitting unit that emits light in a frame sequence so that light of the same color temperature is emitted based on the color temperature;
Control means for performing imaging three times with one shutter release, and sequentially, the R, G, and B strobe lights whose light emission amounts are adjusted by the adjusting means are sequentially applied in a predetermined order from the surface-sequential light emission strobe. Control means for causing the imaging means to perform an imaging operation in synchronization with the strobe lights of R, G, and B and acquiring R, G, and B frame sequential image data from the imaging means;
Recording means for storing the acquired frame-sequential image data in a temporary storage device, and then recording it on a recording medium;
A digital camera with a surface-sequential light emission strobe. A field sequential strobe that emits R, G, B strobe light in a field sequential manner;
Black and white imaging means;
Means for fetching information for determining the amount of R, G, B strobe light emitted from the surface sequential light emission strobe in a surface sequential manner;
A color temperature sensor for detecting the color temperature of the object scene;
Adjusting means for respectively adjusting the light emission amounts of R, G, and B strobe lights that are emitted in a field sequential manner from the surface sequential light emission strobe light, the information for determining the light emission amount of the captured strobe light and the color temperature; Adjusting means for respectively adjusting the amount of strobe light emitted from each light emitting unit that emits light in a frame sequence so that light of the same color temperature is emitted based on the color temperature set to the color temperature detected by the sensor;
Control means for performing imaging three times with one shutter release, and sequentially, the R, G, and B strobe lights whose light emission amounts are adjusted by the adjusting means are sequentially applied in a predetermined order from the surface-sequential light emission strobe. Control means for causing the imaging means to perform an imaging operation in synchronization with the strobe lights of R, G, and B and acquiring R, G, and B frame sequential image data from the imaging means;
Recording means for storing the acquired frame-sequential image data in a temporary storage device, and then recording it on a recording medium;
A digital camera with a surface-sequential light emission strobe.   6. The digital camera with a frame sequential light emission strobe according to claim 4, further comprising recording means for recording the acquired frame sequential image data of R, G, B on a recording medium.   The image processing apparatus includes a combining unit that combines the acquired R, G, and B frame sequential image data to generate one image data, and a recording unit that records the generated image data on a recording medium. A digital camera with a field sequential light emission strobe according to claim 4 or 5.

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