PATENT ABSTRACTS OF JAPAN
`
`(11)Publication number:
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`2004-135183
`
`(43)Date of publication of application : 30.04.2004
`
`(51)Int.CI.
`
`H04N 5/225
`
`6033
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`7/16
`
`H04N 5/238
`
`// H04N101 :00
`
`(21)Application number: 2002-299501 (71)Applicant : FUJI PHOTO FILM CO LTD
`
`(22)Date of filing:
`
`11.10.2002
`
`(72)[nventor : TSUBAKI HISANOBU
`
`TANAKA HIROSHI
`
`(54) DIGITAL CAMERA
`
`
`
`(57)Abstract:
`
`PROBLEM TO BE SOLVED: To provide a
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`digital camera capable of deciding whether a
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`strobe light reaches a main object, without
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`using a distance meter.
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`SOLUTION: The digital camera takes a
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`pre-photograph by hahc depressing its release
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`button to obtain a pre-image, determines
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`photographing conditions, based on the
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`obtained pre-image, and takes a regular
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`photograph by fully depressing the release
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`button to obtain a regular image. A strobe light
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`reaches an object in a near range but not its
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`background. If the regular image with a strobe
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`

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`light has a higher brightness than the pre-image without strobe light in comparison of
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`the brightness values of both, a reflection of the strobe light is counted to determine
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`that the strobe light reaches.
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`* NOTICES *
`
`JPO and INPIT are not responsible for any
`
`damages caused by the use of this translation.
`
`1.This document has been translated by computer. So the translation may not reflect
`
`the original precisely.
`
`2.**** shows the word which can not be translated.
`
`3.In the drawings. any words are not translated.
`
`CLAIMS
`
`[Claim(s)]
`
`[Claim 1]
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`In a digital camera provided with an imaging means which images an object and
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`obtains a taken image, and a strobe device,
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`Two photography without those with a strobe light and a strobe light is performed to
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`the same object, A digital camera providing a strobe light attainmentjudging means
`
`whichjudges whether a strobe light has reached an object in the case of photography
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`with [ aforementioned ] a strobe light based on brightness information of two images
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`acquired by these two photography.
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`[Claim 2]
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`The digital camera according to claim 1 specifying an object range scale which
`
`expresses rough object distance based on a decided result of the aforementioned
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`strobe light attainmentjudging means.
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`[Claim 3]
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`The digital camera according to claim 1 or 2 photography with the aforementioned
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`strobe light being this photography for obtaining this taken image recorded on a
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`storage medium, and being a pre photograph for photography without a strobe light
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`being performed before this aforementioned photography, and acquiring a
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`photographing condition of this aforementioned photography.
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`

`

`[Claim 4]
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`one of Claims 1-3 recording the aforementioned decided result on a storage medium
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`with a taken image -- a digital camera of a description.
`
`[Translation done.]
`
`* NOTICES *
`
`JPO and INPIT are not responsible for any
`
`damages caused by the use of this translation.
`
`1.This document has been translated by computer. So the translation may not reflect
`
`the original precisely.
`
`2.**** shows the word which can not be translated.
`
`3.In the drawings, any words are not translated.
`
`DETAILED DESCRIPTION
`
`[Detailed Description of the Invention]
`
`[0001]
`
`[Field of the Invention]
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`The present invention relates to the digital camera which equipped the major object
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`with the function tojudge whether the strobe light has reached.
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`[0002]
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`[Description of the Prior Art]
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`The digital camera recorded on memory card by imaging means, such as CCD, by
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`using as digital data the taken image which might be imaged in the object has spread.
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`Photographed image data is recorded on memory card as a graphics file of EXIF form,
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`for example. As everyone knows, an EXIF standard is standardized by JEITA (Japan
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`Electronics and Information Technology Industries Association), and can store the
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`attendant information relevant to image data in the graphics file of EXIF form besides
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`image data.
`
`[0003]
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`There are various kinds of things, such as photographing condition data about
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`

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`photographing conditions, such as existence of exposure time, a diaphragm value, a
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`luminance value, and a strobe light, date data, photographing mode information which
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`were photoed, in this attendant information. In a graphics file, an information storage
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`area called a tag for every kind of these attendant information is provided.
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`Attendant information is stored in each tag.
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`[0004]
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`When printing an image, such attendant information is referred by the printer, and it is
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`used in order to perform a suitable image processing. For example, if the existence of
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`a strobe light is known, exposure correction processing according to it can be
`
`performed. However, like [ at the time of carrying out a scenery shot], when major
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`object distance is far, even if it carries out a metaphor strobe light, a strobe light
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`does not reach even a major object. In this case, if an image processing is performed
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`only based on the information on the existence of a strobe light, since the mistaken
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`correction will be made, good image quality cannot be obtained.
`
`[0005]
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`Since the irradiation range of a strobe light can be presumed, if the distance
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`measurement data obtained in the case of focusing is used in addition to the
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`information on the existence of the aforementioned strobe light, it can bejudged
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`whether the strobe light has actually reached. Photosensor is made to image an
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`object image as two images as a ranging system. There are a system (for example,
`
`see Patent Document 1) which computes object distance using the phase contrast
`
`of these images, a system (for example, see Patent Document 2) which computes
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`distance by consisting of light projection elements and a photo sensor, and carrying
`
`out light reception of the optical signal reflected with an object, etc.
`
`[0006]
`
`[Patent document 1]
`
`.JP,H6—222258,A
`
`[Patent document 2]
`
`.JP,H8—286100,A
`
`[0007]
`
`[Problem to be solved by the invention]
`
`By the way, the spread of digital cameras in recent years is remarkable, and a camera
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`type [ a variety of] is sold increasingly. There is a type of in it called the short form
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`digital camera characterized by small size and low cost. In such a short form digital
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`camera, miniaturization and low cost-ization are attained by eliminating a focusing
`
`

`

`mechanism by using a fixed focus-type taking lens, or simplifying the image
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`processing inside a camera etc. For this reason, since photographing image quality
`
`cannot but fall victim, in order to acquire good print picture quality, it increases also
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`to a prevalent digital camera and picture correction processing in the case of a print
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`needs to be performed properly. Thejudgment information of whether from such a
`
`background, the strobe light has actually reached the graphics file recorded with a
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`short form digital camera to the major object was wanted to be recorded.
`
`[0008]
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`However, when the distance measuring equipment of the ranging system mentioned
`
`above was provided to the short form digital camera, it had a problem that it will be
`
`connected with cost increase.
`
`[0009]
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`An object of the present invention is to provide the digital camera which canjudge
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`whether the strobe light reached to a major object, without providing distance
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`measuring equipment.
`
`[0010]
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`[Means for solving problem]
`
`In order to attain the aforementioned purpose, the digital camera of the present
`
`invention, In the digital camera provided with the imaging means which images an
`
`object and obtains a taken image, and the strobe device, Two photography without
`
`those with a strobe light and a strobe light is performed to the same object, Based on
`
`the brightness information of two images acquired by these two photography, the
`
`strobe light attainmentjudging means whichjudges whether the strobe light has
`
`reached the object in the case of photography with [ aforementioned ] a strobe light
`
`was provided.
`
`[0011]
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`Based on the decided result of the aforementioned strobe light attainmentjudging
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`means, it is good to specify the object range scale showing rough object distance.
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`[0012]
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`[t is good to consider it as the pre photograph for considering it as this photography
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`for obtaining this taken image recorded on a storage medium in photography with the
`
`aforementioned strobe light, performing photography without a strobe light before
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`this aforementioned photography, and acquiring the photographing condition of this
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`aforementioned photography. [t is good to record the aforementioned decided result
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`on a storage medium with a taken image.
`
`[0013]
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`

`

`[Mode for carrying out the invention]
`
`Eigiis a block diagram showing the composition of the digital camera 10. The digital
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`camera 10 converts the photoed image data to the graphics file of EXIF form, and
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`records it on the memory card 11 set to a main part enabling free attachment and
`
`detachment. Attendant information other than image data is stored in a graphics file.
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`[0014]
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`CPU12 controls each part of a main part of the digital camera 10 according to the
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`operation signal input from the operating part 13. The operating part 13 consists of a
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`power button, a release button, a mode change dial, a general-purpose key, etc. A
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`mode change dial switches the photographing mode which photos an image, and the
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`reproduction mode which carries out the repeat display of the photoed image to
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`LCD14. The menu screen which performs various setting out besides a reproduced
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`image is displayed on LCD14. A general-purpose key moves the cursor in a menu
`
`screen, and is used for selection of a setting—out item. The through drawing for an
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`object check is displayed on this LCD14, and it functions on it also as an electronic
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`view finder.
`
`[0015]
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`As a setting-out item, there are various kinds of items, such as luminescence mode
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`of the strobe device 16 and setting out of a record pixel number, for example. There
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`are an auto mode which emits light as strobe light mode according to object
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`luminosity, bloodshot-eyes mitigation mode which reduces red eye,
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`forced-light—emission mode which is not concerned with object luminosity but is
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`made to emit light forcibly, luminescence prohibition mode which forbids a strobe
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`light forcibly, etc.
`
`[0016]
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`The digital camera 10 is provided with the strobe light attainment determining
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`function whichjudges whether the strobe light has reached major object distance
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`when speed light photography is carried out. Since the range of the strobe light was
`
`decided about, a near major object range scale can be specified by investigating
`
`whether the strobe light reached. That is, it can specify that a major object range
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`scale is a close-range view whenjudged with the strobe light having reached, and
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`when judged with another side and a strobe light not having reached, it can specify
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`that it is a distant view. A decided result is stored in the object region tag in a
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`graphics file, and is recorded on the memory card 11 with image data.
`
`[0017]
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`The fixed focus-type taking lens 18 is provided by the front face of the digital camera
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`

`

`10. Behind the taking lens 18, CCD series 33 is arranged as an image sensor. As
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`everyone knows, by arranging a many photo detector to matrix form, CCD series 33
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`is provided with the photoelectric surface, passes a photographing optical system,
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`and carries out photoelectric conversion of the object light imaged to this
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`photoelectric surface. The microlens array for condensing light to each pixel ahead of
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`a photoelectric surface and the color filter array by which the filter of each color was
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`regularly arranged so that each pixel might correspond to R, G, or B, respectively are
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`arranged.
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`[0018]
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`COD series 33 outputs the electric charge accumulated for every pixel as an imaging
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`signal serial one line at a time synchronizing with the vertical transfer clocks and the
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`horizontal transfer clock which are supplied from COD driver 36. The charge storage
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`time (exposure time) of each pixel is decided by the electronic shutter driving signal
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`given from COD driver 36. A timing signal is input into COD driver 36 from the timing
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`generator 31, and CCD series 33 is operated based on this timing signal.
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`[0019]
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`The imaging signal of the analog incorporated from CCD series 33 is input into the
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`analog signal processing circuit 38. The analog signal processing circuit 38 consists
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`of a correlated double sampling circuit (CDS), an auto gain controller (AGO), and an
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`AD converter (ADC). ODS removes the noise of an analog signal and AGO regulates
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`the gain of an analog signal automatically. ADC carries out digital conversion of the
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`analog signal, and generates image data. This image data is COD—RAW data which
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`have a concentration value of R, G, and B for every pixel, and these CCD-RAW data
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`are input into DSP (Digital Signal Processor) 41. The timing signal from the timing
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`generator 26 is supplied also to the analog signal processing circuit 38, an electric
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`charge incorporates from CCD series 33, and rare ** timing and a synchronization
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`are taken.
`
`[0020]
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`DSP41 is an [0 chip which consists of the AE/AWB circuit 44, the image input
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`controller 46, the image processing circuit 47, the compression processing circuit 48,
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`the media controller 49, and the video encoder 51, While performing various kinds of
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`signal processing from the analog signal processing circuit 38 to the input image data,
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`it accesses to the display to LCD14 of through drawing, and the memory card 11, and
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`a graphics file is written.
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`[0021]
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`The image input controller 46 incorporates the aforementioned COD-RAW data from
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`

`

`the analog signal processing circuit 38. and writes this in the frame memory 42. The
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`frame memory 42 is a memory for work used when DSP41 performs various signal
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`processing to image data. The frame memory 42 is connected with each part of
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`CPU12 and DSP41 via the data bus 55. As the frame memory 42. SDRAM
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`(Synchronous Dynamic Random Access Memory) which performs data transfer
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`synchronizing with the bus clock signal of a constant period is used. for example.
`
`[0022]
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`A pre image other than through drawing and this image is among the image data
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`incorporated from CCD series 33. Through drawing is an image for a check used for
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`flaming as it mentioned above. and while photographing mode is chosen. it is imaged
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`with a predetermined interval. By the video encoder 51. through drawing is converted
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`to a composite signal and outputted to LGD14. A pre image is an image acquired by a
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`pre photograph. A pre photograph means the photography for determining the
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`photographing condition at the time of being carried out before photoing this image.
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`and photoing this image.
`
`[0023]
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`When a release button is half-pressed. CPU12 detects a half-press signal and makes
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`COD series 33 perform a pre photograph. The acquired pre image is once written in
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`the frame memory 42 via DSP41. Based on this pre image. the AE/AWB circuit 44
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`determines a photographing condition. Based on the aforementioned data. the
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`AE/AWB circuit 44 measures object luminosity and determines shutter speed etc.
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`An AWB circuit is an automatic white balance circuit. and adjusts the white balance
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`at the time of photography automatically.
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`[0024]
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`If a release button is pressed fully. this photography will be performed and this image
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`will be captured. The pixel number of this image can change a record pixel number by
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`setting out of fine ** Normal etc.. although the maximum pixel number is determined
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`by the pixel number of COD series 33. Rather than this image. there are few images
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`of through drawing or a pre image. for example. it is incorporated with about 1/16
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`pixel number of this image.
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`[0025]
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`By the image processing circuit 47. as opposed to the data of this image in which
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`various kinds of image processings were performed. the compression processing
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`circuit 48 performs compression processing by compression format. such as JPG.
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`and generates a graphics file. Attendant information is stored in each tag at this
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`graphics file generate time. The media controller 49 is accessed to the memory card
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`

`

`11, and performs writing and reading of a graphics file. in reproduction mode, after
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`the image data compressed from the memory card 11 is read and an expansion
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`process is performed by the compression processing circuit 48, it is outputted to
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`LCD14.
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`[0026]
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`Y data whose image processing circuit 47 is a luminance signal to image data about
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`image quality correction processings, such as a gamma correction, sharpness
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`correction, and contrast correction, and COD-RAW data, YC processing converted
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`to YC data consisting of Cr data which is Cb data and the red color-difference signal
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`which are blue color-difference signals is performed.
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`[0027]
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`The image processing circuit 47 performs strobe light attainment decision processing
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`based on this image acquired by this photography and the pre image acquired by the
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`pre photograph, when speed light photography is performed. The luminance
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`difference of the specific portion in each screen of a pre image and this image is
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`compared, and a strobe light attainmentjudging is performed by investigating the high
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`luminance region where the luminance difference is large.
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`[0028]
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`For example, as shown in Eng”; when the major object 61a photos the scene 61 which
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`is a person, suppose that the strobe device 16 emitted light. In that case, when a
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`strobe light actually reaches the major object 61a, the luminosity of a part with the
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`reflected light of a strobe light and this image goes up. On the other hand, even if a
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`metaphor stroboscope emits light since a strobe light does not reach a distant view
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`when a major object photos the scene 63 which is scenery, as shown in flgAB), a
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`strobe light does not reflect with an object and the luminosity of this image and a pre
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`image does not change. Thus, the luminosity of a pre image and this image is
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`measured, and when the luminosity of this image is high, it canjudge with the strobe
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`light having reached the major object.
`
`[0029]
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`flgiM) shows this image 71 and the pre image 72. When comparing this image 71
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`with the pre image 72, the luminance value of all the regions of each screen may be
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`compared, but in order to shorten processing time more, it is good to set up the
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`comparison object regions 73 and 74 as a specific region used as a comparison
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`object. Since a major object is near the center in a screen in many cases, in this
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`example, the comparison object region has been set up in the center of a screen. The
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`pixel number of the pre image 72 is 320x240 to the pixel number of this image 71
`
`

`

`being 1280x960, for example, and it is 1/16 of the pixel number of this image 71.
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`Therefore, the comparison object region 74 of the pre image 72 is also extracted in
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`1/16 of the comparison object region 73 of this image 71 of sizes. When the pixel
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`number of the comparison object region 73 is 320x240. the pixel number of the
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`comparison object region 73 is set to 80x60.
`
`[0030]
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`Comparison of a luminance value is performed as follows. First, the luminance
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`difference dY of the corresponding portion in the comparison object region 73 and 74
`
`is searched for. As shown in Eig3_(0), if each pixel of Ya and the comparison object
`
`region 74 is set to Db and the luminance value is set to Yb for Da and its luminance
`
`value, each pixel of the comparison object region 73, The portion corresponding to
`
`pixel Db“ at the upper left of [ in a screen ] the comparison object region 74 is
`
`equivalent to 16 pixel Dan at the upper left of [ in a screen] the comparison object
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`region 73 — Da44. For this reason. if in charge of comparison. it is the average
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`luminance value Yaavg of the luminance value Ya of the pixel Da for 16 pieces of the
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`comparison object region 73 first. It asks and is this average luminance value Yaavg.
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`The luminance difference dY with luminance value Yb of the pixel Db of the
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`comparison object region 74 is searched for. Similarly, the pixel number part
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`above-mentioned comparison of the comparison object region 74 is repeated, and
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`the luminance difference dY of each pixel Db and each portion of the comparison
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`object region 73 corresponding to it is searched for.
`
`[0031]
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`The luminance difference dY searched for is totaled and the average luminance
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`difference dYavg of the luminance difference dY searched for is searched for by
`
`dividing this by the pixel number in the comparison object region 74. This average
`
`luminance difference dYavg compares the threshold value S set up previously, and
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`when a threshold value S twist also has the large luminance difference dYavg, it
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`judges with the strobe light having reached. When the luminance difference dYavg is
`
`below the threshold value 8, itjudges with a strobe light not reaching. An object
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`range scale is specified based on this decided result. This object range scale is
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`stored in the object distance range tag in a graphics file as one of the attendant
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`information.
`
`[0032]
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`Thus, since a strobe light attainmentjudging is performed by measuring the
`
`luminosity of the pre image acquired by CCD series 33, and this image. it is not
`
`necessary to range with distance measuring equipment. Therefore, low cost-ization
`
`

`

`can be attained.
`
`[0033]
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`Hereafter, according to the flow chart of Eng_and Fig.5, it describes about the
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`operation by the above-mentioned composition.[f a power supply is turned on and
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`photographing mode is chosen, through drawing incorporation of COD series 33 will
`
`be started, and the repeat display of the through drawing will be carried out to LCD14.
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`A photography person performs flaming, looking at this display.
`
`[0034]
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`Half press of a release button will perform a pre photograph. A pre image is captured
`
`by this pre photograph, and it is written in the frame memory 42. The AE/AWB circuit
`
`44 reads this pre image, and determines a photographing condition (exposure value).
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`Shutter speed is adjusted based on this photographing condition.
`
`[0035]
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`Full press of a release button will perform this photography. COD series 33 captures
`
`this image and writes this data in the frame memory 42. The image processing circuit
`
`47 performs various kinds of image quality correction processings to this image of
`
`this. When speed light photography is performed, strobe light attainment decision
`
`processing is performed after completing image quality correction processing. In
`
`strobe light attainment decision processing, the corresponding pixels in each
`
`comparison object region 73 and 74 of the pre image 72 and this image 71 are
`
`measured with the flow chart of Eigjuso that it may be shown, and the luminance
`
`difference dY is searched for. And after comparing a part for all the pixels in the
`
`comparison object region 74, the average luminance difference dYavg of the
`
`luminance difference dY searched for is searched for. When a threshold value S twist
`
`also has the large luminance difference dYavg searched for, itjudges with the strobe
`
`light having reached the major object. In below the threshold value S, itjudges with a
`
`strobe light not reaching.
`
`[0036]
`
`An object range scale is specified based on this decided result. That is, it specifies
`
`that it is a short distance when a strobe light reaches, and when not having reached,
`
`it specifies that it is a long distance. And a graphics file including this object range
`
`scale information is generated, and it records on memory card. When carrying out
`
`next photography, the above-mentioned procedure is repeated.
`
`[0037]
`
`[n printing the image recorded on the memory card 11, with reference to the object
`
`distance range tag in a graphics file, as for a printer, a major object distinguishes a
`
`

`

`short distance or a long distance. And though strobe light information is set to ON,
`
`when an object range scale is a long distance, it isjudged that the strobe light has
`
`not reached. Since a proper image processing can be performed by this, good print
`
`picture quality is acquired.
`
`[0038]
`
`Although an average luminance difference is searched for and this average luminance
`
`difference and threshold value are compared by the above-mentioned embodiment
`
`from the luminance difference of a picture element position [ in the case of a strobe
`
`light attainmentjudging / in a comparison object region ], it mayjudge from the
`
`number of the luminance difference beyond a certain threshold value. Simply, each
`
`average luminance value of each comparison object region may be calculated, and
`
`these luminance differences and threshold values may be compared.
`
`[0039]
`
`Although described in the example with rectangular form of a comparison object
`
`region, of course, it may not be rectangular and may be circular. Although the
`
`comparison object region was described in the example set as the center of a screen
`
`only one, it may not be a center and there may be more than one. Although described
`
`in the example which compares two images from which a pixel number differs, two
`
`images of the same pixel number may be compared.
`
`[0040]
`
`Although it is not concerned with a photographing scene but the strobe light
`
`attainmentjudging is always made to be performed in the above-mentioned
`
`embodiment, depending on a photographing scene, a difficult ** case also has a
`
`strobe light attainmentjudging. For example, when a photographing scene is very
`
`bright, even if a metaphor strobe light reaches, it is thought that a big difference does
`
`not arise in the luminosity of a pre image and this image. For this reason, when it is
`
`beyond a predetermined luminance value with the luminance value of a pre image, it
`
`may not be made not to perform a strobe light attainmentjudging. In this case, it is
`
`good to, record the information that ajudgment is impossible on an object distance
`
`range tag for example.
`
`[0041]
`
`When speed light photography was carried out, it described in the example in which a
`
`strobe light attainmentjudging is always performed, but a user may enable it to set
`
`up whether decision processing is performed.
`
`[0042]
`
`Although an object range scale is specified and he is trying to store this in a graphics
`
`

`

`file based on a strobe light attainmentjudging, it may be made to store in a graphics
`
`file the information itself which the strobe light reached whether it has lent.
`
`[0043]
`
`Although the decided result is described in the example stored in a graphics file, it is
`
`also good to use a decided result for the image processing inside a camera, without
`
`storing in a graphics file.
`
`[0044]
`
`Although the short form digital camera without a focusing mechanism was described
`
`for the example, the present invention may be applied to the digital camera provided
`
`with the focusing mechanism.
`
`[0045]
`
`[Effect of the Invention]
`
`As described in details above, the digital camera of the present invention, In the
`
`digital camera provided with the imaging means which images an object and obtains a
`
`taken image, and the strobe device, Two photography without those with a strobe
`
`light and a strobe light is performed to the same object, Based on the brightness
`
`information of two images acquired by these two photography, The digital camera
`
`which can judge whether the strobe light reached the major object can be provided
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`without providing distance measuring equipment, since the strobe light attainment
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`judging means which judges whether the strobe light has reached the object in the
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`case of photography with [ aforementioned ] a strobe light was provided.
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`[Brief Description of the Drawings]
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`[Drawing 1][t is a block diagram showing the outline of the electric composition of a
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`digital camera.
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`[Drawing 2][t is an explanatory view of a strobe light attainmentjudging.
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`[Drawing 3][t is an explanatory view showing the comparison method of a pre image
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`and this image.
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`[Drawing 4][t is a flow chart which shows a photographing procedure.
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`[Drawing 5][t is a flow chart which shows a strobe light attainment determining
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`procedure.
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`[Explanations of letters or numerals]
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`10 Digital camera
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`16 Strobe device
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`33 CCD series
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`41 DSP
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`42 Frame memory
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`

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`47 Image processing circuit
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`71 This image
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`72 Pre image
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`[Translation done.]
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`