Umted States Patent
`
`[19]
`
`[11] Patent Number:
`
`4,847,680
`
`
`Okino
`[45] Date of Patent:
`Jul. 11, 1989
`
`[54]
`
`IMAGE PICKUP APPARATUS WITH WHITE
`BALANCE CONTROL
`«
`
`Tadashi Okino, Kanagawa, Japan
`Inventor:
`[75]
`[73] Assignee: Canon Kabushiki Kaisha, Tokyo,
`Japan
`
`[21] Appl. No.: 99,620
`,
`F113d=
`
`[22]
`
`SeP- 22’ 1937
`
`Foreign Application ‘Priority Data
`[30]
`Sep. 24, 1986 [JP]
`Japan ................................ 61-223826
`Nov. 4, 1986 [JP]
`Japan ............ 61-260602
`
`Japan ............ 61-260603
`Nov. 4, 1986 [JP]
`Japan ................................ 61-260604
`Nov. 4, 1986 [JP]
`
`Int. Cl.4 ......................... H04N 9/73; H04N 9/04
`[51]
`[52] US. Cl. ........................................ 358/29; 358/41;
`358/43; 354/430
`[58] Field of Search ................... 358/29 C, 29, 41, 43,
`358/44, 50; 354/430, 482, 414
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`5/1974 Murata et a1.
`Re. 28,025
`.................. 354/414 X
`2,455,116 11/1948 Gittus ............
`.‘.. 354/430 X
`
`4,281,337
`7/1981 Nakamura .............. 358/29 C
`
`........... 358/29 C X
`4,499,487 2/ 1985 Takayama et al.
`
`
`1/ 1986 Takayama et al.
`............... 358/29 C
`4,567,509
`
`4/1986 Kutaragi .............
`358/29 c
`4,584,598
`8/1986 Hashimoto et a1.
`358/29 C
`4,605,955
`
`
`4,616,253 10/1986 Hashimoto et a1.
`358/41 X
`4,700,219 10/ 1987 Tanaka et a1.
`.................... 358/41 X
`FOREIGN PATENT DOCUMENTS
`
`3322835 12/1983 Fed. Rep. of Germany .......... 9/535
`55-70833
`5/1980 Japan ................................... 354/430
`60-176380
`9/1985 Japan ................................ 358/29 c
`
`Primary Examiner—James J. Groody
`Assistant Examiner—E. Anne Favis
`
`Attorney, Agent, or Firm—Robin, Becker & Daley
`[57]
`ABSTRACT
`
`An image pickup apparatus of the kind using an object
`illuminating device is provided with a colorimetric
`circuit which is arranged to measure the hue of ambient
`light existing around an object to be photographed
`other than the illumination light of the illuminating
`device. The light source of the illuminating device is
`provided with a hue adjustment circuit. The apparatus
`is thus arranged to adjust the hue of the illumination
`light generated by the illuminating device to the hue of
`the ambient light.
`
`21 Claims, 12 Drawing Sheets
`
`11]
`
`”GMT ”WRITE
`
`WRIIETRIG GIT
`
`PHOTOMETRIC GKT
`
`2'
`
`31
`
`IRIS
`DRIVER
`
`SHUTTER
`DRIVER
`
`14
`
`RELEASE
`SWITGH
`
`11
`
`
`GUIPUTIRG/ GURTRDL IIKT
`
`
`
`-
`
`SHUTTER
`
`-
`
`
`SIEIAL
`PROCESSING
`
`GIT
`
`
`
`REBITRITIIIG
`GIT
`
`0mm sum
`
`2:
`
`3:
`
`13
`
`PllRER SUPPLY
`SWITCH
`
`12
`
`61061 GKT
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`H
`
`9
`
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`
`W,ag3233.5
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`Sheet 2 of 12
`
`4,847,680
`
`Fl 5.2
`
`23
`
`
`
` PHUTUHETRIG
`
`6H
`
`
`
`35
`
`
`
`37
`
`
`PHUTDIETRIG
`
`
`
`HTC, Exhibit 1007
`
`0U
`
`31
`
`
`
`DIFFUSINGPLAIE
`
`PHDTUMETRIE
`GKT
`
`33
`
`
`
`34
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`Sheet 3 of 12
`
`4,847,680
`
`FIGA
`
`YES
`
`
`
`
`
`SET YIHITE BALANCE
`(CORRESPONDING TD HANIIAUN
`ILLUIINATIDN EFFICIENCY)
`
`s2
`
`33
`
`vmvnmx?
`
`ND
`
`ummuwnmmlccm
`
`310
`
`SET IYHITE DALANCE
`(INCLUDING LICHT SOURCE)
`
`SI I
`
`-
`
`% SI?
`
`YES
`
`NO
`
`TURN [IN LICHT SOURCEIO
`
`313
`
`
`
`TURN ON LICHT SDURCEID
`(NANIHUN EFFICIENCY)
`
`
`
`OPERATE
`PHOTOHETHIC ONTO
`
`
`
`APPOSITE
`ICHT QUANTITY?
`
`YES
`
`
`
`
`
`OPERATE PHOTONETRIC ONTO
`
`SIS
`
`ADJUST
`LICHT
`
`
`ADJUST
`
`LICHT
`
`
`APPOSITE
`LICHT QUANTITY?-
`
`YES
`
`
`II
`
`RELEASE
`SWITCH 14 CLOSED?
`
`YES
`
`OPERATE IRIS 11mm:
`
`818
`
`OPERATE SHUTTER DHIYER 3h
`
`3T9
`
`OPERATE SICNAL
`PROCESSING CNTS
`
`320
`
`OPERATE RECORDING CAT]
`
`SOT
`
`322
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`Jul. 11,1989
`
`Sheet 4 of 12
`
`4,847,680
`
`F I 6.5
`
`45
`
`42
`
`A
`
`41
`
`
`
`
`UGHI
`
`SflUflBE an
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`Sheet 5 of 12
`3‘”
`
`4,847,680
`'
`
`YES
`
`
`
`
`
`SET WHITE BAIAIIIIE
`(MAXIMUM EETIUIEIIUV
`IIF LIGHT SUURGE III)
`
`
`
`‘
`
`.3-
`
`0mm PHUTUIIETIIIG cm
`
`352
`
`363
`
`STU
`
`SS]
`
`2
`
`SEE
`
`RELEASE
`SWITGH 14 SLUSEU?
`
`.
`
`YES
`
`357
`
`I” w I
`“=2
`
`
`SET UULIIR TEMPERATURE
`SET UUIUR TEMPERATURE
`
`
`UFIIGHTSUURUE TU
`[IF lIGHTSITURUE TO
`OPERATE IIIIS DRIVER 2h
`(THE SAME VALUE AS AMBIENT EIGHT)
`(MAXIMUM EEEISIEIIUY)
`I
`
`UFERATE SHUTTER DRIVER 3h
`
`
`
`383
`
`384
`
`373
`
`UPERATE SIGNAL
`PHOGESSIIIG cm
`
`359
`
`370
`
`IIPERATE IRIS DRIVER 2h
`
`um snumnaa
`
`sn
`
`man on LIGHT suunum
`
`372
`
`GIUSE SHUTTER 3a
`
`
`
`374
`
`III’EIIATE REIIIJRDIIIG cm
`
`375 m
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`_ US. Patent
`
`@91
`
`m
`
`6
`
`1
`
`4
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`
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`9eana_
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`Sheet 7 of 12
`
`4,847,680
`
`
`
`ANALOGSWITGH
`
` .
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`Sheet 8 of 12
`
`4,847,680
`
`
`
`am..
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`
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`
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`
`HTC, Exhibit 1007‘
`
`5:2;ADV0—.0_n.
`
`HTC, Exhibit 1007
`
`
`
`

`

`US. Patent
`
`0091L,1m
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`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`
`
`
`

`

`US. Patent
`
`Jul. 11, 1989
`
`-
`
`Sheet 10 of 12
`
`4,847,680
`
`
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`US. Patent
`
`0an7
`
` mw3:_Ew:3AUvm—mv—n—u.EEM.Il.||.||.||||IIJ.|I||IL|Im_.%Amvm—GC
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`
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`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`
`

`

`US. Patent
`
`Jul. 11,1989
`
`Sheet 12 of 12
`
`4,847,680
`
`
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`1
`
`4,847,680
`
`MAGE PICKUP APPARATUS WITH WHITE
`' BALANCE CONTROL
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`This invention relates to an image pickup apparatus
`and more particularly to a photo-electric converting
`type image sensing apparatus which; is often used in
`combination with an object illuminating device.
`2. Description of the Related Art
`The sensitivity of image sensors which have been
`used for the image pickup apparatuses of the above
`stated kind is not always sufficient for image sensing
`conditions. In the event of an image pickup operation in
`a dark place, insufficient sensitivity of the image sensor
`is compensated for by illuminating an image sensing
`object with an illuminating device. Such illumination
`has been also used as an auxiliary light for softening the
`shadow of the object.
`However, a photographing (or image pickup) opera-
`tion using an illuminating device (or a flash device) is
`not always performed under dark conditions. Further,
`on some occasions, a contribution from coexisting sta-
`tionary (ambient) light is not ignorable even in the event
`of photographing with flash because of low intensity of
`the flash light due, for example, to a high reflection
`factor of the object or the like.
`Under such conditions, mere white balance adjust-
`ment of the image pickup apparatus solely for an ambi-
`ent light or solely for the flash light hardly permits
`accurate color reproduction.
`SUMMARY OF THE INVENTION
`
`This invention is made in view of the above stated
`problem of the prior art. It is therefore a principal ob-
`ject of this invention to provide an image pickup appa-
`ratus which is capable of giving an apposite white bal-
`ance for both the illumination by existing stationary
`ambient light on the photographing object and the aux-
`iliary illumination by an illuminating device.
`To attain this object, an embodiment of this invention
`is provided with a light source (or an illuminating de-
`vice) which is capable of continuously changing the hue
`of the light thereof and also with a colorimetric circuit.
`The embodiment is thus arranged to measure the hue of
`ambient light obtained without the light of an illuminat-
`ing device and then to cause the illuminating device to
`illuminate the object by generating a light of the same
`hue as that of the ambient light.
`The embodiment arranged in this manner is capable
`of reproducing an image in its original color with a
`white balance obtained appositely to both the existing
`ambient light and the light of the illuminating device
`employed.
`Further, to attain this object, another embodiment of
`this invention is arranged to separately measure the
`quantity of light obtained by the ambient light from that
`of light obtained by flash illumination; and to make
`white balance adjustment by prorating the amplifying
`gain of the ambient light and that of flash illumination
`according to a ratio between the two light quantities
`thus separately measured.
`More specifically, the image pickup apparatus which
`is arranged according to this invention to have an opti-
`cal image formed on an image sensor and to take out the
`image by converting it into a plurality of color or chro-
`minance signals comprises:
`flashing means; storage
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`65
`
`2
`means for storing color temperature data relative to the
`flashing means; light measuring means arranged to mea-
`sure the luminance intensity of ambient light and that of
`light emitted by the flashing means separately from
`each other; color measuring means for measuring color
`temperature due to the ambient light; amplifying means
`for controlling the balance between the color signals
`formed by the image sensor; and control means for
`controlling an amplification gain of the amplifying
`means according to the value of the luminance intensity
`measured by the light measuring means, the value of the
`color temperature measured by the color measuring
`means and the color temperature data relative to the
`flashing means.
`The above stated arrangement, enables the embodi—
`ment to obtain a white balance according to both the
`color temperature of the ambient light and that of the
`flash light in cases where the contributions of both of
`them are not ignorable.
`To attain the above stated object, a further embodi-
`ment of this invention adjusts a white balance on the
`basis of measured values of the light quantity of a flash
`light and that of an ambient light. More specifically, an
`image pickup apparatus arranged according to this in-
`vention to have an optical image formed on the surface
`of an image sensor and to take out the image by convert-
`ing it into a plurality of chrominance or color signals
`comprises: flash means; storage means for storing color
`temperature data about the light of the flash means; first
`detecting means arranged to measure the luminance
`intensity of the flash light of said flash means; second
`detecting means arranged to measure the luminance of a
`photographing object
`resulting from ambient
`light;
`color measuring means for measuring color temperature
`resulting from the ambient light; amplifying means ar-
`ranged to control a balance between the color signals
`produced from said image sensor; white balance adjust-
`ing means arranged to adjust a white balance by con-
`trolling the amplification gain of the amplifying means
`according to the measured values obtained by the first
`and second detecting means, the value of color tempera-
`ture measured by the color measuring means and the
`value of the color temperature data about the flash
`means.
`
`The embodiment arranged in this manner is capable
`of obtaining a white balance on the basis of both the
`color temperature of the ambient light and that of the
`flash light according to their weights in case of photo-
`graphing where both the contributions of the ambient
`light and the flash light are not ignorable.
`Further, to attain the above stated object, a still fur-
`ther embodiment of this invention is arranged to make
`white balance adjustment on the basis of light quantity
`values obtained by accumulating and storing, over an
`exposure time, the light quantity of flash light and that
`of ambient light by dividing each of them into two
`primary colors of, for example, red and blue.
`More specifically, an image pickup apparatus which
`is arranged as the above stated embodiment to have an
`optical image formed on the surface of an image sensor
`and to take out the image by converting it into a plural-
`ity of chrominance signals comprises: flash means; color
`measuring means arranged to measure, over the expo-
`sure time of the image sensor, color temperature infor-
`mation on the flash light of the flash means and color
`temperature information on ambient light other than the
`flash light; and adjusting means for adjusting the color
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`3
`balance of the chrominance signals produced from the
`image sensor according to the overall color temperature
`value measured by the color measuring means. There-
`fore, in case of photographing where contributions of
`both the ambient light and the flash light are not ignor-
`able, a white balance is obtainable according to the
`color temperature of both of them.
`Other objects and features of this invention will be-
`come apparent from the following detailed description
`of embodiments thereof taken in connection with the 10
`accompanying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`5
`
`FIG. 1 is a block diagram showing the electric circuit
`of an image pickup device arranged according to this 15
`invention as a first embodiment thereof.
`
`FIG. 2 is a circuit diagram showing the photometric
`circuit of the embodiment.
`
`20
`
`30
`
`FIG. 3 is a diagram showing the colorimetric circuit
`of the embodiment.
`FIG. 4 is a flow chart showing a sequence of photo-
`graphing processes of the embodiment.
`FIGS. 5 and 6 are diagrams showing two examples of
`arrangement of the light source of the embodiment.
`FIG. 7 is a flow chart showing another sequence of 25
`photographing processes.
`FIG. 8 is a block diagram showing the arrangement
`of a second embodiment of this invention.
`FIG. 9 is a circuit diagram showing the arrangement
`of a photometric circuit included in FIG. 8.
`FIGS. 10(A) to 10(H) show in a timing chart the
`operation of the second embodiment.
`FIG. 11 is a block diagram showing the arrangement
`of a third embodiment of this invention.
`FIG. 12 is a circuit diagram showing the arrangement 35
`of the colorimetric circuit of the third embodiment.
`FIGS. 13(A) to 13(G) show in a timing chart the
`operation of a fourth embodiment of this invention
`which employs the arrangement shown in FIG. 12.
`FIG. 14 is a block diagram showing the arrangement 40
`of a variable gain amplifier which is included in the
`arrangement shown in FIG..8.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`45
`
`This invention is further described through the fol-
`lowing description of embodiments thereof:
`FIG. 1 shows in a. block diagram the electric circuit
`of a photo-electric converting type image pickup appa-
`ratus arranged as a first embodiment of this invention. 50
`An optical system 1 consists of optical lenses, etc. which
`are arranged to form on the surface of an image sensor
`4 an image of an object to be photographed. The em-
`bodiment comprises an iris (stop) 2a and a driver 2b for
`the iris; a shutter 3a and a driver 3b for the shutter; and 55
`the image sensor 4 which is arranged to convert an
`image of the object into an electrical signal. The image
`sensor 4 may be a camera tube, a CCD (charge coupled
`device), an MOS type solid-state image sensor or the
`like.
`- Referring further to FIG. 1, a driver 5 is arranged to
`drive the image sensor 4. A signal processing circuit 6 is
`arranged to convert an electrical signal read out from
`the image sensor 4 into the prescribed form of a video
`signal. A recording circuit 7 is arranged to record the 65
`video signal on a recording medium, such as a magnetic
`tape or a magnetic disc. A photometric circuit 8 is ar-
`ranged to measure the luminance of an object to be
`
`60
`
`4,847,680
`
`4
`photographed. A colorimetric circuit 9 is arranged to
`measure the hue of light with which the object is illumi-
`nated. A light source 10 is arranged to provide an object
`illuminating light in the event of an object having an
`insufficient degree of luminance. As will be further
`described later on, this light source 10 permits adjust-
`ment of the hue (color temperature) of the light thereof.
`A computing/control circuit 11 is arranged to control
`applicable parts by performing various computing oper-
`ations and making discriminations as necessary. A clock
`circuit 12 is arranged to determine the operation timing
`of the various parts. A reference numeral 13 denotes a
`powe supply switch. A release switch 14 is arranged to
`enable the photographer to designate the timing of pho-
`tographing.
`The photometric circuit 8 can be easily arranged by
`means of a known circuit as shown in FIG. 2. FIG. 2
`
`includes an operational amplifier 21; a light receiving
`element 22 which is, for example, a silicon photo diode
`or the like and has a short—circuit current in proportion
`to the intensity of light incident thereon. A reference
`numeral 23 denotes a diode. In this circuit, a voltage Vo
`which is generated at the output terminal 0 of the opera-
`tional amplifier 21 can be expressed as:
`
`Vo = qu ln [sec
`
`wherein,
`k: Boltzmann constant
`
`(1)
`
`T: ambient temp. (absolute temp.)
`q: electric charge of one electron
`Is: reverse saturation current of diode 23
`Ispec: forward current flowing to diode 23 (=photo
`current flowing to light receiving element 22 o:
`intensity of light received)
`In other words, the light measurement output voltage
`V0 is proportional to the natural logarithm of the inten-
`sity of light received and can be expressed as:
`
`kT
`
`an= 18 mV
`
`(2)
`
`Therefore, the voltage Vo increases by 18 mV every
`time the luminance of the object (o: the receiving light
`intensity of the photometric circuit 8) increases two
`times. The luminance of the object can be found by
`measuring the voltage output of the circuit 8.
`The colorimetric circuit 9 of FIG. 1 can be arranged
`as shown in FIG. 3 in accordance with a known circuit
`arrangement. Referring to FIG. 3, a reference numeral
`31 denotes a diffusing plate. Numerals 32, 33 and 34
`denote color filters, which are arranged to transmit, for
`example, only the colors R (red), G(green) and B (blue)
`respectively. Numerals 35, 36 and 37 denote photomet-
`ric circuits which are similar to the photometric circuit
`shown in FIG. 2 respectively. In this circuit arrange-
`ment, a difference between the outputs of the two pho-
`tometric circuits 35 and 36 can be expressed as follows:
`
`qu 1n
`
`[seclxggz
`
`_ qu ln Isgch)
`I;
`
`= kT ln Igpcggl
`q
`15pc(R)
`
`(3)
`
`Therefore, this gives a ratio between the green (G)
`and red (R) components of the light incident on the
`colorimetric circuit 9.
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`5
`Likewise, a difference between the outputs of the two
`photometric circuits 36 and 37 can be expressed as fol-
`lows:
`
`kT
`q
`
`Is
`Ispc<B>
`
`1“
`
`5
`
`(4)
`
`That gives a ratio between the green (G) and blue (B)
`components of the light incident on the circuit 9.
`The ratio of components of the incident light which is
`expressed as:
`
`Red (R):Green (G):Blue (B)
`
`(5)
`
`thus can be obtained to permit detection of the hue of
`the incident light.
`In case of photographing with an illuminating device
`which generates a temporally continuant light, such as
`an illumination lamp,
`3. photographing (or
`image
`pickup) operation is performed as described below with
`reference to FIG. 4 which is a flow chart of a sequence
`of processes:
`When the power supply switch 13 (FIG. 1) is closed,
`the image pickup apparatus begins to operate (a step
`81). The luminance of the object is measured by the
`photometric circuit 8 (a step 82). At a next step S3: A
`check is made to find whether the measured luminance
`of the object is below a predetermined value. If so, the
`ambient light which is illuminating the object from
`around it is sufficiently dark to permit photographing
`with illumination by the light source 10.
`In this case, at a step S4, the white balance is set at a
`color temperature which obtains at the maximum light
`emission efficiency of the light source 10. The mode of
`the light source 10 is shifted to a mode in which it has
`the maximum light emission efficiency. At a step SS:
`The light source 10 is lighted up. At a step S6: The
`luminance of the object is again measured by the photo-
`metric circuit 8. At a step S7: A check is made to find
`whether the measured luminance of the object is within
`a photographable range. If the luminance is found to be
`outside of the photographable range of the image
`pickup apparatus (too bright or too dark), the flow of
`operation comes to a step S8. At the step S8: The inten-
`sity of the light of the light source 10 is adjusted. The
`flow then comes back to the step 86 to check for the
`lightness of the illumination. When the illumination by
`the light source 10 is found to be apposite to the object
`at the step S7, the flow comes to a step 817. At the step
`517: The flow of operation awaits the operation of the
`release switch 14. When the release switch 14 is oper-
`ated at the step 817, the flow proceeds to a step 818. At
`the step 818: The computing/control circuit 11 first
`causes the iris driver 2b to stop down the aperture of the
`iris 2a. At a step 819: Then,
`the computing/control
`circuit 11 causes the shutter driver 3b to drive the shut-
`ter 30. The shutter 3a is then opened for a given period
`of time thus to have the image sensor 4 exposed to light.
`In this instance, the aperture value of the iris 20 and the
`exposure time of the shutter 30 are computed by the
`circuit 11 on the basis of information on the-object’s
`luminance obtained at the step S6 through the photo-
`metric circuit 8.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`4,847,680
`
`6
`video signal is recorded by the recording circuit 7 on
`the recording medium. At a step 522: The photograph-
`ing operation comes to an end.
`In case that the ambient light of the object is found, at
`the step S3, to be not ignorably weak after light mea-
`surement is performed at the step $2, the embodiment
`operates as follows: In this case, since the influence of
`the color of the ambient light illuminating the object is
`not ignorable, the flow of operation comes to a step 810.
`At the step 810: The computing/control circuit 11
`causes the colorimetric circuit 9 to measure the hue of
`the ambient light illuminating the object. At a step 811:
`On the basis of the colorimetric value thus measured,
`the control circuit 11 then sets the white balance of the
`
`signal processing circuit 6 and the color temperature
`(absolute temperature) of the light source 10. At a step
`512: A check is made, on the basis of the value of light
`measured at the step 82, to find whether the object is
`photographable without the aid of the light source 10.
`At a step 813: If the aid of the the light source is neces-
`sary, the light source 10 is lighted up. At steps $14 to
`816: Then, the lightness of the light source 10 is ad-
`justed to a photographable range of the image pickup
`apparatus through processes which are similar to those
`of the above stated steps S6 to SS. At steps $17 to 821:
`a photographing operation is carried out. In that in-
`stance, the parameter values of the iris 2a and the shut-
`ter Sa are computed by the computing/control circuit
`11 on the basis of the measured light value obtained at
`the step 814.
`Further, if it is found at the step S12 that the lightness
`is found to be sufficient for photographing without the
`aid of the light source 10, the flow of operation jumps to
`the step 817 to have the photographing processes car-
`ried out at the steps 817 to 821. In that event, the pa-
`rameter values of the iris 2a and the shutter 3a are com-
`puted by the computing/control circuit 11 on the basis
`of the light value measured at the step 82.
`The color temperature of the light source 10 is ar-
`ranged to be set in a manner as described below with
`reference to FIGS. 5 and 6 which show the details of
`examples of the light source arranged to have the hue
`(color temperature) thereof variable respectively:
`Referring to FIG. 5, a light source 41 is arranged to
`have its lightness (luminance intensity) variable by a
`voltage applied between electrodes A and B thereof.
`Reference numerals 42, 43 and 44 respectively denote
`color filters of, for example, red (R), green (G) and blue
`(B). Filters 45, 46 and 47 which have no hue are ar-
`ranged to have their transmission factors variable by
`electrical signals applied to electrodes C, D and E.
`With the light source arranged as shown in FIG. 5,
`the color temperature of the light source 10 is adjusted
`to the measured color value of the ambient light on the
`object in the following manner: The light intensity ratio
`among the colors red, green and blue is adjusted by
`adjusting the ratio among the transmission factors of the
`filters 45, 46 and 47. Then, the intensity of the light of
`the color temperature is adjusted (at each _of the light
`adjusting steps S8 and $16 of FIG. 4) through the me-
`dium of the voltage applied between the electrodes A
`and B.
`
`At a step 820: After completion of the exposure, the
`object’s image is read out from the image sensor 4 in the
`form of an electrical signal at a suitable timing and is
`converted into a video signal of a prescribed form by
`the signal processing circuit 6. At a step 821: Then, the
`
`65
`
`Further, in the event of weak intensity of the ambient
`light, as in the case of “YES” at the step S3 of FIG. 4,
`the object is illuminated directly by the light of the light
`source 41 with all the filters 42 to 47 removed. Then,
`since the light is then not attenuated by any of the filters
`
`HTC, Exhibit 1007
`
`HTC, Exhibit 1007
`
`

`

`7
`42 to 47, the efficiency of illumination is greatly im-
`proved. In this instance the white balance of the image
`pickup apparatus is adjusted to the light of the light
`source 41. Data relative to this may be arranged to be
`supplied to a memory area provided within the com-
`puting/control circuit 11 of FIG. 1 from the light
`source 10.
`
`Referring now to FIG. 6, another method for chang-
`ing the hue of the light source 10 is as follows: In this
`instance, a plurality of light sources 51, 52 and 53 are
`discretely arranged to have the luminance of their light
`emission variable by changing voltages applied to elec-
`trodes A, B and C respectively. Color filters 54, 5 and
`56 are provided, for example, for red (R), green (G) and
`blue (B). With the light source arranged as shown in
`FIG. 6, the ratio (of color temperature) among the color
`components of red, green and blue of the light passing
`through the color filters 54, 55 and 56 is adjustable by
`changing a ratio among the voltages applied to the
`electrodes A, B and C. Light adjustment is carried out
`according to the light that increases the absolute values
`of voltages applied to the electrodes A, B and C.
`Further, the light source arrangement of FIG. 5 may
`be changed as follows: By omitting the filters 43 and 46,
`illumination is effected mainly with a freely passing
`portion of light and the hue (color temperature) is ad-
`justed. with two colors. This modification lessens the
`degree of attenuation of light by virtue of omission of
`the filters 43 and 46 and yet still permits adjustment of
`hue.
`
`5
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`In the case of FIG. 6, the same advantageous effect is
`attainable by omitting the color filter 55.
`For further simplification of the light source arrange-
`ment, the light of the light source 41 or 52 may be ar— .
`35
`ranged to have a tinge of cyan with the transmission
`factor or the lightness of the filter 45 or the light source
`51 adjusted accordingly. In the event of this modifica-
`tion, the color filters 43 and 44 of FIG. 5 can be omitted
`and the filters 46 and 47 can be replaced with a one
`filter. As for the arrangement of FIG. 6, the color filters
`55 and 56 and the light source 53 can be omitted by this
`modification.
`
`Further, the arrangement of the light source shown in
`FIGS. 5 or 6 may be changed to replace the color filter
`42 or 54 with a magenta filter and the color filter 43 or
`55 with a cyan filter. This change then makes the color
`filter 44 or 56 and the light source 53 omissible.
`Further, in the case of FIG. 6, the light source 53 and
`the color filters 54, 55 and 56 are omissible if the light
`sources 51 and 52 are tinged with colors.
`Next, in case of photographing with an illumination
`device which is arranged to generate light in a pulse-
`like state like in the case of, for example, a flash device,
`the embodiment operates as follows: FIG. 7 is a flow
`chart showing by way of example a sequence of pro-
`cesses of such a photographing operation. The sequence
`of processes can be carried out by the electric circuit
`arrangement, etc. of the embodiment as shown in FIG.
`1. Referring to FIG. 7, at a step S61: The image pickup
`apparatus begins to operate with the power supply
`switch 13 closed. At a step S62: The luminance of the
`object is measured by the photometric circuit 8. At a
`step S63: A check is made to find whether the lightness
`of the object is below a predetermined value. If the
`lightness is found to be lower than the predetermined
`value, it indicates that the ambient light illuminating the
`object from around it is sufficiently dark and ignorable
`thus permitting a photographing operation with the
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4,847,680
`
`8
`light source 10 under a condition ensuring the highest
`light emitting efficiency thereof. In that event, the flow
`of operation proceeds to a step S64. At the step S64:
`The computing/control circuit 11 sets the white bal—
`ance of the signal processing circuit 6 at a value corre-
`sponding to this illuminating condition. At a step S65:
`After the white balance is set, a parameter X for dis-
`crimination of each case is set at 0. At a step S66: The
`flow waits for an operation on the release switch 14
`(FIG. 1). At a step S66: The flow comes to this step
`when the release switch 14 is operated. At a step 867: A
`check is made for the value of the parameter X. Since,
`in this instance, the value of the parameter X is O, the
`flow jumps to a step S68. At the step S68: The color
`temperature of the light source 10 is set in such a way as
`to obtain the maximum efficiency of the light source 10.
`At a step 569: The aperture of the iris 2a is stopped, for
`example, down to a value designated by the light source
`10. At a step S70: The shutter 3a is opened. At a step
`S71: The light source 10 is caused to flash or emit light.
`At a step S72: The shutter 30 is closed after the light
`emission comes to a stop. At a step S73: After that,
`information on the image of the object is read out in the
`form of an electrical signal and is converted into a video
`signal by the signal processing circuit 6. At a step S74:
`The video signal is recorded on a recording medium by
`the recording circuit 7. At a step S75: The series of
`photographing processes comes to an end.
`If the intensity of the ambient light is found not ignor-
`able at the step S63, the flow of operation comes to a
`step S76. At the step S76: The color temperature of the
`ambient light is measured by the colorimetric circuit 9.
`At a step S77: The white balance of the signal process-
`ing circuit 6 is set on the basis of the measured value of
`color. At a step S78: Next, the light is checked on the
`basis of a measured photometric value obtained at the
`step S62 to find whether photographing is possible
`without the aid of the light source 10. At a step S79: If
`the result of the check made at the step S78 is in the
`negative (NO), the value of the discriminative parame-
`ter X is set at 1. At a step S66: The flow waits for an
`operation on the release switch 14. When the release
`switch 14 is operated, a next step is decided according
`to the value of the discriminative parameter X.
`In this instance, since the value X is at 1 indicating
`that the influence of the ambient light is not ignorable,
`the flow comes to a step 880. At the step 580: The color
`temperature of the light source 10 is adjusted to a value
`apposite to the color temperature of the ambient light.
`After that, the steps S69 to S75 are executed in exactly
`the same manner as in the case of X=O.
`
`In case that photographing is determined to be possi-
`ble without the aid of the light source 10 at the step 578,
`the flow of operation comes to a step 581. At a step 881:
`The discriminative parameter X is set at 2 and the flow
`comes to the step S66 to wait for the operation on the
`release switch 14. When the release switch 14 is oper-
`ated, a check is made for the value of the discriminative
`parameter X at the step S67.
`Since the value of the discriminative parameter X is 2
`in that instance, the flow jumps to a step SS3. At a step
`883: The iris 2a is stopped down to a parameter value
`computed by the computing/control circuit 11 accord-
`ing to the photometric value obtained at the s