`Sasaki et a1.
`
`5,018,017
`[11] Patent Number:
`[45] Date of Patent: May 21, 1991
`
`[54] ELECTRONIC STILL CAMERA AND IMAGE
`RECORDING METHOD THEREOF
`
`[75] Inventors: Minoru Sasaki, Tokyo; Mmfumi
`Umeda, Kawasaki; Yoshitomo
`Tagami, Yokohama; Akihiko
`Sugikawa, Yokohama, all of Japan
`[73] Assignee: Kabushiki Kaisha Toshiba, Kawasaki,
`Japan
`[21] Appl. No.: 447,858
`[22] Filed:
`Dec. 8, 1989
`
`[63]
`
`Related US. Application Data
`Continuation-impart of Ser. No. 289,238, Dec. 23,
`1988.
`Foreign Application Priority Data
`[30]
`Dec. 25, 1987 [JP]
`Japan .............................. .. 62-327174
`Feb. 2, 1989 [JP]
`Japan
`l-2252l
`
`Mar. 22, 1989 [JP]
`
`Japan . . . . . . . . . . . .
`
`. . . .. l-67606
`
`Mar. 22, 1989 [JP]
`
`Japan ........................... .. l-67607
`
`H04N 5/30
`[51] Int. Cl.5 ........................ ..
`[52] US. Cl. .................................. .. 358/209; 358/335;
`358/909
`[58] Field of Search ................. .. 358/909, 209, 213.16,
`358/2l3.25, 41, 12, 13, 133, 105, 906, 335
`References Cited
`U.S. PATENT DOCUMENTS
`4,489,351 12/1984 d’Alayer de Costemore
`d’Arc ................................ .. 358/909
`4,745,474 5/1988 Schit‘f ................................ .. 358/105
`
`[56]
`
`4,758,883 7/1988 Kawahara et a]. ............... .. 358/335
`4,802,003 1/1989 Takei et a1. ......................... _. 358/12
`4,837,628 6/1989 Sasaki ................................ .. 358/909
`4,918,523 4/1990 Simon et a1. ........................ .. 358/12
`
`FOREIGN PATENT DOCUMENTS
`
`0289944 11/1988 European Pat. Off. .
`0269581 11/1987 Japan .
`0224561 9/1988 Japan .
`0284987 11/1988 Japan .
`Primary Examiner-Tommy P. Chin
`Attorney, Agent, or Firm-Oblon, Spivak, McClelland,
`Maier & Neustadt
`ABSTRACT
`[57]
`An electronic still camera has a memory card, which is
`detachably provided, for recording photographed
`image data. The electronic still camera comprises a data
`compression unit for compressing image data to be
`recorded, a mode selection unit provided in association
`with the data compression unit to select a recording
`mode or compression mode, a buffer memory for once
`storing the image data compressed in the compression
`mode selected by the mode selection unit, and a deter
`mination unit for determining whether or not the image
`data stored in the buffer memory can be recorded on the
`recording medium. In the electronic still camera, when
`the image data was determined to be unrecordable by
`the determination unit, the image data stored in the
`memory is stored in the buffer memory till the record
`ing medias assumes a recordable state.
`
`18 Claims, 23 Drawing Sheets
`
`LG 1007
`
`1
`
`
`
`US. Patent
`
`May 21, 1991
`
`Sheet 1 of 23
`
`5,018,017
`
`FIG.
`
`2
`
`
`
`US. Patent
`
`May 21, 1991
`
`Sheet 2 of 23
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`5,018,017
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`May 21, 1991
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`May 21, 1991
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`May 21, 1991
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`May 21, 1991
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`May 21, 1991
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`5,018,017
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`9
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`
`US. Patent
`
`May 21, 1991
`
`Sheet 9 of 23
`
`5,018,017
`
`DIRECTORY
`
`I BYTE
`
`FILE N0. (IMAGE NO.)
`
`ENLTSRSYAEIXTI‘ION
`IMAGING SYSTEM
`IMAGE MODE
`
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`525/60.625/5O
`W88? COMPRESSION
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`
`10
`
`
`
`US. Patent
`
`May 21, 1991
`
`Sheet 10 of 23
`
`5,018,017
`
`FAT AREA
`(256 BYTE)
`
`DATA AREA
`(IOK BYTE x 255=2.55M BYTE)
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`
`11
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`
`
`U.S. Patent
`
`May 21, 1991
`
`Sheet 11 of 23
`
`5,018,017
`
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`
`12
`
`12
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`
`US. Patent
`
`May 21, 1991
`
`Sheet 12 of 23
`
`5,018,017
`
`I START I
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`May 21, 1991
`
`Sheet 13 of 23
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`May 21, 1991
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`May 21, 1991
`
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`May 21, 1991
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`May 21, i991
`
`Sheet 18 of 23
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`5,018,017
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`May 21, 1991
`
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`5,018,017
`
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`
`May 21, i991
`
`Sheet 20 of 23
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`5,018,017
`
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`U.S. Patent
`
`May 21, 1991
`
`Sheet 21 of 23
`
`5,018,017
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`
`May 21, 1991
`
`Sheet 22 of 23
`
`5,018,017
`
`DIRECTORY
`
`I BYTE FILE NO. (IMAGE NO.)
`
`‘NF°RMAT'°N
`CLASSIFICATION
`
`IMAGE, VOICE, DATA
`
`IMAGING SYSTEM
`
`525/60.625/5O
`
`IMAGE MODE
`
`VOICE MODE
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`
`ENTRY BLOCK NO.
`
`NUMBER OF BLOCKS USED
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`
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`
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`
`255
`
`A
`
`FIG.
`
`I7
`
`23
`
`23
`
`
`
`U.S. Patent
`
`May 21, 1991
`
`Sheet 23 of 23
`
`5,018,017
`
`A
`
`12A;
`
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`
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`
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`
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`
`24
`
`24
`
`
`
`1
`
`5,018,017
`
`ELECTRONIC STILL CAMERA AND IMAGE
`RECORDING METHOD THEREOF
`
`CROSS-REFERENCES TO THE RELATED
`APPLICATIONS
`
`The present application is a continuation-in-part ap-
`plication of U.S. patent application Ser. No. 289,238
`filed on Dec. 23, 1988.
`
`BACKGROUND OF THE INVENTION
`The present invention relates to an electronic still
`camera, which uses,
`for example, a semiconductor
`memory card as a recording medium, for recording still
`images on the recording medium.
`
`DESCRIPTION OF THE RELATEDHART
`
`Electronic still cameras which use a solid state imag-
`ing device such as a CCD (charge coupled device) for
`photographing still images of subjects and recording the
`still images on rotatable magnetic recording medium,
`that is, a video floppy, are considered to replace con-
`ventional still cameras for photographing and recording
`still images by use of the photosensitivity of silver salt
`films, that is, photographic films using silver salt photo-
`sensitive material, and they have been merchandized.
`However, since this type of electronic still camera uses
`the rotatable magnetic recording medium, a driving unit
`for driving the rotatable magnetic recording medium
`relative to the recording head must be provided inside
`the camera, thus making it difficult to reduce the size of
`the camera. A solid state electronic still camera system
`for recrding image information on a memory card using
`a semiconductor memory (that is, storing image infor-
`mation in a semiconductor memory of a memory card),
`as a system which has no driving unit and is suitable for
`small sized cameras, has been considered by the same
`applicant (U.S. application Ser. No. 073,160, Minoru
`Sasaki). A typical example of this type of electronic still
`camera is shown in FIG. 13.
`An image of the subject is transmitted via lens 121,
`diaphragm 122 and color filter 120, and formed on CCD
`126 which is used as the imaging device in which the
`optical image is subjected to a photoelectric conversion.
`An output signal of CCD 126 is subjected to a predeter-
`mined process in preprocessing circuit 127, converted
`into a digital signal by means of analog-to-digital (A/D)
`converter 128, and then recorded on memory card 115.
`In this case, a signal from each picture element of the
`imaging device is recorded in the digital form on mem-
`ory card 115. The signal of each picture element of the
`imaging device is subjected to a predetermined process
`such as the amplification, white-ba.lance correction and
`7 correction as the pre-processing. Picture element
`data, which has been subjected to the pre-processing in
`a sequence according to the picture element array, is
`recorded on memory card 115. In the reproduction
`mode, memory card 115 is set in a reproducing unit, and
`data stored in memory card 115 is subjected to a prede-
`termined signal processing and digital-to—analog (D/A)
`conversion, and then supplied to a TV (television) mon-
`itor which in turn displays the data as an image. In FIG.
`13, case 110, release switch 111 for triggering the imag-
`ing operation, battery 123 used as a power source, shut-
`ter control circuit 124 for controlling diaphragm 122
`and electronic shutter operation, CCD driving circuit
`125, and monitoring unit 130 are also shown. CCD
`driving circuit 125 is used to control and drive shutter
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`control circuit 126, pre-processing circuit 127, A/D
`converter 128 and memory card 115. Monitoring unit
`130 displays the photographed image based on signals
`transmitted via pre-processing circuit 127 at the time of
`photographing and is used as a view finder.
`As described above, wherein data corresponding to
`each picture element of the solid state imaging device is
`recorded on the memory card, the signal processing is
`simple and the device is simple in construction. How-
`ever, if the recording conditions such as the number of
`picture elements and the arrangement of color filters of
`the solid state imaging device of the electronic still
`camera are changed, for example, the arrangement of
`data recorded on the memory card or the amount of
`data per frame will be changed accordingly. Therefore,
`the recorded memory card is not interchangeably used
`for another type of electronic still camera system, that
`is, an electronic still camera having the number of pic-
`ture elements and arrangement of color filters different
`from those of the electronic still camera used for re-
`cording the image data on the memory card.
`If a single electronic still camera is designed so as to
`record image under different recording conditions, the
`recorded memory card may be interchangeably used to
`some extent. However, in this case, the memory capac-
`ity required for recording one frame of image data of
`the photographed still image varies depending on the
`recording conditions (recording modes) set at the time
`of photographing. Therefore,
`in a case where new
`image data is written into a recording area in which one
`frame of image data has been previously recorded and
`erased, the memory capacity may sometimes be insuffi-
`cient for recording the new image data, thus making it
`impossible to record the new image data.
`SUMMARY OF THE INVENTION
`
`An object of this invention is to solve the aforemen-
`tioned disadvantages and provide a new electronic still
`camera and an image recording method by which the
`memory capacity required for recording one frame of
`data can be changed as required, the number of images
`to be recorded on one recording medium can be effi-
`ciently changed according to the image quality, and
`which can flexibly cope with a shortage in residual
`amount of the recording medium mounted at the time of
`photographing and the non-coincidence of the record-
`ing area when a suitable frame is erased and a new
`image is recorded.
`In an electronic still camera of this invention, a re-
`cording medium for recording a photographed image
`data, for example, a memory card is detachably pro-
`vided. The electronic still camera comprises a data
`compression unit for compressing an image data to be
`recorded, a mode selection unit provided in association
`with the data compression unit to select a recording
`mode, that is, a compression mode, a buffer memory for
`temporarily storing an image data compressed in the
`compression mode selected by the mode selection unit,
`and a determination unit for determining whether or not
`the image data stored in the buffer memory can be re-
`corded on the recording medium. In the electronic still
`camera, when “NO” is determined by the determination
`unit, the image data stored in the memory is stored in
`the buffer memory of the camera until the recording
`medium assumes a recordable state, that is, until a new
`memory card is mounted, for example. Preferably, the
`compression mode includes an uncompression mode not
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`applied with the data compression by the data compres-
`sion unit.
`
`In the electronic still camera according to a preferred
`embodiment of the present invention, an image signal
`subjected to photoelectric conversion by a solid state
`imaging device is digitalized by a signal processing
`circuit and coded, and the coded digital data is recorded
`on a memory card. In the electronic still camera, an
`image signal is converted into a brightness signal and
`two color-difference signals by a signal processing cir-
`cuit and recorded on a memory card. In the electronic
`still camera, the image data can be compressed and the
`total bit capacity for recording one frame of image data
`can be reduced by changing the number of samples and
`by non-linear quantitizing an error with an expected
`signal to reduce the number of bits required to express
`one sample data, and the brightness signal and two’
`color-difference signals can be written into the memory
`card as the recording medium. Also, the number of
`frames of images written into a memory card can be
`changed as desired accordingly. In the electronic still
`camera, the memory of the memory card is divided into
`blocks of fixed capacity, a number or name is set to each
`block, data in each frame is divided into several blocks
`and recorded, and the number of blocks used for each
`frame and the number or name of the first block are
`recorded whereby even if the memory of different ca-
`pacity is used every frame, writing, reading, erasing or
`rewriting can be easily made.
`In the electronic still camera according to the present
`invention, there are a plurality of compression modes
`having different compressibility, and an user can suit-
`ably select any of these modes. In the electronic still
`camera as described, even if the capacity of the record-
`ing medium or the data amount of one frame is deter-
`mined so that the capacity capable of being recorded by
`one recording medium, for example, a memory card, is
`the natural number times of the data amount of one
`frame in all the recording modes, when a plurality of
`different compression modes are selected for one re-
`cording medium, for example, the memory card, a sur-
`plus of the memory capacity less than one frame inevita-
`bly sometimes occurs. In other words, there sometimes
`occurs a case where a shortage of capacity not capable
`of recording an image of one frame on the memory
`capacity finally left occurs. In the light of this, in the
`electronic still camera of the present invention, when a
`shortage in capacity of the memory card attached oc-
`curs for photographed image data, and the transfer of
`the photographed image data to the memory card is
`effected for the first time when a new memory card is
`attached and the image data assumes a state capable of
`being recorded. Accordingly, the user can suitably se-
`lect and photograph the compression mode without
`being troubled by the residual capacity of the recording
`medium or the kind of compression modes when the
`compression mode is selected.
`In the electronic still camera according to the present
`invention, the number of images capable of being re-
`corded on the recording medium for example memory
`card, can be efficiently changed depending on the
`image quality, and even if plural kinds of image data
`processed according to different modes are mixed and
`recorded on a single recording medium, no inconve-
`nience occurs. Moreover, in the electronic still camera,
`it is possible to erase only data of one frame to record a
`new image data in an easy manner. Furthermore, in the
`electronic still camera, even in the case where the short-
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`age in capacity of the recording medium attached has
`been found after imaging had been made, the imaging
`content can be recorded on another recording medium.
`Accordingly, the present invention can provide an elec-
`tronic still camera and an image recording method
`which can be conveniently used as a system including
`the recording medium.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective view showing an appearance
`of an electronic still camera according to a first embodi-
`ment of this invention;
`FIG. 2 is a diagram schematically showing the con-
`struction of the electronic still camera shown in FIG. 1;
`FIG. 3 is a perspective view illustrating the basic
`construction of a semiconductor memory card used in
`the electronic still camera shown in the embodiment of
`FIG. 1;
`FIG. 4 is a diagram illustrating the detail construction
`of the memory card shown in FIG. 3;
`FIG. 5 is a diagram showing the modeled construc-
`tion of a CCD array used in the embodiment shown in
`FIG. 1;
`FIGS. 6A and 6B are diagrams showing the detailed
`construction of the electronic still camera shown in
`FIG. 2;
`FIGS. 7 and 8 are views illustrating the sampling
`points of the image data in the embodiment shown in
`FIG. 1 on the assumption that the positions thereof lie
`on a 2-dimensional plane;
`FIGS. 9A to 9E are views illustrating the recording
`formats of the memory card used in the embodiment
`shown in FIG. 1;
`FIG. 10 is a flowchart showing the process in detail
`at the time of photographing effected by the embodi-
`ment shown in FIG. 1;
`,
`FIG. 11 is a block diagram showing the schematic
`construction of a reproducing unit for reproducing an
`image from the memory card recorded by the camera of
`this invention;
`FIGS. 12A and 12B are block diagrams showing the
`detailed construction of a second embodiment of this
`invention;
`FIG. 13 is a diagram showing the construction of the
`conventional electronic still camera;
`FIGS. 14A and 14B are block diagrams showing the
`detailed construction of a third embodiment of this
`invention;
`FIG. 15 is a flowchart showing the process in detail
`at the time of photographing in the embodiments shown
`in FIGS. 14A and 14B;
`FIGS. 16A and 16B are block diagrams showing the
`detailed construction of a fourth embodiment of this
`invention;
`FIG. 17 is a view for explaining a format of a direc-
`tory within a memory card in the embodiments shown
`in FIGS. 16A and 16B; and
`FIGS. 18A and 18B are views illustrating examples of
`mode switch.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`There will now be described an electronic still cam-
`era according to an embodiment of this invention with
`reference to the accompanying drawings.
`An electronic still camera system, as used hereinafter
`is defined as including an electronic still camera and a
`reproducing unit. The electronic still camera is used to
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`take a picture of a subject and record the image on a
`semiconductor memory card used as recording me-
`dium, and the reproducing unit is used to read out image
`information from the memory card and transfer the
`image information to TV receiver or the like for dis-
`play.
`FIG. 1 is a perspective view of the electronic still
`camera as viewed from the rear upper point thereof,
`and the explanation for portions thereof which have the
`same functions as those of an ordinary still camera
`(using a photographic film) is omitted. Electronic still
`camera 10 includes reset switch 9, release 11, photo-
`graphing mode switch 12 and photographed picture
`number displaying unit 13. Further, insertion slot 14 is
`provided for pemtitting insertion of semiconductor
`memory card 15 on the right side of electronic still
`camera 10. Shutter speed selection dial 18 is disposed on
`the electronic still camera 10. These elements will be
`described more in detail later.
`FIG. 2 schematically shows the basic construction of
`electronic still camera 10. In the photographing opera-
`tion, focusing is effected by lens system 21 and the shut-
`ter speed is adequately set by operating shutter speed
`selection dial 18 in the same manner as in the ordinary
`still camera. Diaphragm 22 is controlled by control
`circuit 24, and the shutter speed is adjusted by a so-
`called electronic shutter. The electronic shutter adjusts
`the shutter speed by controlling the charge storing time
`in CCD array 26 used as an image device. An image of
`a shutter is formed on CCD array 26 via lens system 21.
`When the photographing operation is started and
`release 11 is set into the halfway position (the release
`button is depressed halfway) by an operator or user, the
`power source voltage from power source 23 using a
`battery is supplied to the respective electronic circuit
`sections (that is, when the power source switch not
`shown is turned on, the power source voltage is sup-
`plied only to a portion required in the preparation stage
`of photographing, and the power source voltage is sup-
`plied to other portions required for photographing for
`the first time when the release 11 assumes the halfway
`position). The amount of incident light is measured by
`exposure sensor 19, and control circuit 24 controls dia-
`phragm 22 according to the measured amount of inci-
`dent light. The external color temperature is measured
`by white balance sensor 17, and control circuit 24 gen-
`erates a white balance control signal according to the
`measured color temperature.
`When release 11 is further depressed from the half-
`way position to the fully depressed position (the release
`button is fully depressed), control circuit 24 produces a
`shutter pulse. In response to the shutter pulse, driving
`circuit 25 supplies control signals to CCD array 26,
`pre-processing circuit 27, A/D conversion circuit 28
`and signal processing 31 which are in turn operated in
`response to the respective control signal. An image
`information signal formed of an analog signal from
`CCD array 26 is supplied to A/D conversion circuit 28
`via pre-processing circuit 27 and is converted into a
`corresponding digital signal. The image information
`signal thus converted into the digital form is subjected
`to a predetermined signal processing in signal process-
`ing circuit 31. A digital image information signal from
`signal processing circuit 31 is supplied to semiconductor
`memory card 15 together with a control signal with an
`address signal. In this way, the image information signal
`corresponding to the photographed still image is stored
`in semiconductor memory card 15.
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`Prior to the photographing, the user can selectively
`set the format of data to be stored in semiconductor
`memory card 15 by operating mode switch 12. Mode
`switch 12 is used to select and set a desired one of a
`plurality of modes for different image qualities. Mode
`selection by mode switch 12 makes it possible to change
`the amount of digital data required for storing one
`frame image (i.e., the number of image frames which
`can be stored in one memory card 15). For example,
`when high quality mode is set, one frame image is stored
`as digital data of 640 Kbytes with the highest image
`quality. When mode “B” is set, one frame image is
`stored as digital data of 320 Kbytes with the second
`highest image quality, and when mode “C” is set, one
`frame image of 160 Kbytes is stored with the third high-
`est image quality. Further, when mode “D" or low
`image quality mode is set, one frame image of 80 Kbytes
`corresponding to the smallest memory space for one
`frame is stored. If memory card 15 is provided with a
`memory of 2.56 Mbytes, for example, it is possible to
`store 4, 8, 16 and 32 frames into one memory card 15 in
`modes “A”, “B”, “C” and “D”, respectively. The selec-
`tion of the recording modes by the mode switch 15 is
`effected every frame. The details of a method for stor-
`ing data into the memory card 15 will be described
`later.
`
`In the above description, the data amount in one
`frame is set by selecting one of the invariable modes.
`However, the compression rate of data amount may be
`set freely set by the user. In the case of the former (i.e.,
`selecting one mode), for example, a dial-type switch
`12A, wherein modes (A) to (D) correspond to four
`selections of a dial 12Al, as shown in FIG. 18A, can be
`used as the mode switch 12. In this type of mode switch,
`the dial 12A1 is rotated to select one of the modes (A)
`to (D). In the case of the latter (i.e., freely setting the
`compression rate of data amount), a switch 12B, which
`comprises, as shown in FIG. 18B, a pair of triangular
`button switches 12B1 and l2B2 arranged in opposite
`directions and a display 12B3 for displaying the com-
`pression rate, can be used. In the mode switch 12, the
`compression rate 1/N (N: an integer having a predeter-
`mined value or less that determines the limit of com-
`
`pression) is displayed on the display 12B3. Upon opera-
`tion of the button switches 12B] and 12B2, the value N
`is increased or decreased to set a desired compression
`rate.
`
`FIG. 3 shows the basic construction of memory card
`15. Memory card 15 is constituted by a printed circuit .
`board having a plurality of random access memory
`(RAM) chips 36 mounted thereon. External terminals
`32 including data terminals, address terminals and con-
`trol terminals, and power source terminals 33 are pro-
`vided on one side of memory card 15. For use of mem-
`ory card 15, it is inserted into electronic still camera 10
`or a reproducing unit. Supply of the power source volt-
`age to memory card 15 is achieved via power source
`terminals 33, and transfer of signals with respect to
`memory card 15 is effected via external terminals 32.
`Exclusive battery 34 used for holding stored data is built
`in memory card 15. Further, memory card 15 includes
`power source switching circuit 35 which switches the
`power source of RAM chip 36 from built-in battery 34
`to power source 23 of electronic still camera 10 or the
`power source of the reproducing unit when memory
`card 15 is inserted into electronic still camera 15 or the
`reproducing unit, respectively.
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`FIG. 4 shows an example of memory card 15 having
`20 1 M-byts RAM chips 361 to 3620. External terminals
`321 to 323 and power source terminals 33 are provided
`on one side of memory card 15. External terminals 321
`to 323 include 8-bit data terminals 321, address terminals
`322 for receiving address information A0 to A20 and
`control terminals 323. Memory card 15 of FIG. 4 has a
`memory capacity of 20 Mbytes (2.56 Mbytes). Control
`terminals 323 include terminal CS for selection of RAM
`chips 36, write pulse terminals WP and card selection
`terminals CE for selecting one of cards when a plurality
`of cards are used. One of decoders 1211 and 1212 is
`selected by an input supplied to terminals CS. Decord-
`ers 1211 and 1212 respectively correspond to RAM
`chips 361 to 3610 and 3611 to 3620.
`CCD array 26 which is a solid state imaging device is
`used as an imaging device for photographing still frame
`images, for example. A frame interline transfer type
`CCD may be suitable for the CCD array 26 used in the
`electronic still camera of this invention, for example.
`FIG. 5 shows the modeled construction of one exam-
`ple of a frame interline transfer type CCD solid state
`imaging device.
`The CCD array has image receiving portions 51
`formed of photoelectric conversion elements such as
`photodiodes arranged in a matrix form. Vertical trans-
`ferring portions 52 are arranged along and adjacent to
`the columns of image receiving portions 51. Charges in
`each of image receiving portions 51 are transferred to a
`corresponding one of the vertical transferring portions
`52 in response to field shift pulse qbvl, and the trans-
`ferred from one end thereof to charge storage section 54
`acting as a frame memory section via transfer gate 53.
`Signal charges in charge storage section 54 are trans-
`ferred to output circuit 56 via horizontal transferring
`section 55 and then output as an electrical signal. Drain
`portion 57 is arranged adjacent to the other ends of
`vertical transferring sections 52.
`In a case where only one CCD array of this type is
`used to derive out a color image signal, an optical color
`filter for s