Electronic still picture camera

Abstract: There is disclosed an image processing apparatus provided with a converter for converting the input image signal into another signal form; a first unit for generating first control information for causing the converter to compress the input image signal; and a second unit for generating second control information for causing the converter to convert the input image signal into a predetermined signal format suitable for storage in a recording medium. These units avoids the use of separate circuits for conversion into different signal forms, so that the magnitude of circuitry can be reduced.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an image processing apparatus, and an apparatus capable of transmitting image signal. Related Background Art In place for the conventional optical camera utilizing silver halide emulsion, there has been developed an electronic still camera in which an object image is converted into electric signals by an image pickup device and is recorded on a magnetic recording medium, and there has also been developed an electronic still camera having a function of image reproduction. In such conventional electronic still camera, the image signal is read from the image pickup device in synchronization with the rotation of a magnetic disk constituting the recording medium. The color difference signal is converted into line-sequential signal, and the brightness signal and the line-sequential color difference signal are respectively frequency modulated, then frequency multiplexed and recorded on the magnetic disk. In the reproducing circuit, the output of a magnetic head is separated by filters into a brightness component and a line-sequential color difference component, which are respectively frequency demodulated to obtain the brightness signal and the line-sequential color difference signals. The line-sequential color difference signals are converted into line-simultaneous signals by a line-simultaneous circuit consisting of a line sense circuit, a line delay circuit and switches. Thus obtained brightness circuit and line-simultaneous color difference signals are converted by an NTSC encoder into an NTSC image signal which is supplied to an NTSC image monitor, whereby a reproduced image can be obtained. Also in case of transmitting the image, recorded on the magnetic disk, to another location, the transmitting apparatus stores said image in a frame memory after separating it into color component signals of R, G and B, then reading said signals in a predetermined order and sends said signals to a telephone line after conversion into analog signal by a D/A converter. The conventional structure consumes a large electric power because of the use of a 1H (one horizontal synchronization period) delay line in the line simultaneous circuit and for the skew compensation in the field reproduction. While the reproduced image is displayed on the monitor, the magnetic disk has to be constantly rotated, thus requiring additional power consumption. Consequently there is required a battery of a considerably large capacity, in comparison with that in a camera with recording function only. Also in case of transmitting the taken image for example through a telephone line, there is also required a transmitting apparatus for reproducing and transmitting the image recorded on a magnetic disk, but such transmitting apparatus, if constructed as a separate unit, is wasteful because it contains many components and circuits which are common with those in the electronic still camera. Although the foregoing explanation is limited to a conventional electronic camera utilizing magnetic disk, such drawbacks are encountered also in other various image processing apparatus, such as a facsimile apparatus with a monitor unit, or a television telephone. In the electronic still camera handling still images or in the movie camera handling moving image, the image signal is often obtained in some places in the form of primary or complimentary colors, and in other places in the form of brightness signal and color difference signals. The actual signal processing is often conducted by common hardwares, such as image memories or digital signal processors (DSP). For storing the image signal in the image memory, an A/D converter is required for converting the analog signal into digital signal. For this purpose, there is already known a circuit structure utilizing two A/D converters for the brightness signal and the color difference signals, in which the image signal of primary (or complementary) colors is converted into brightness signal and color difference signals, which are then converted into digital signals by said A/D converters. Also there is known a circuit structure utilizing an A/D converter capable of high-speed digitization of serial image signal of primary (or complementary) colors, wherein thus digitized signal is converted into the brightness signal and color difference signals in or after the image memory. In either conventional structure, for effecting the A/D conversion in order to process the image signal of primary complimentary colors and the image signal composed of brightness signal and color difference signals by means of a common digital processing circuit, there is required a conversion circuit for signal conversion into either signal form, and/or a high-speed A/D converter capable of digitizing at least the brightness signal, or preferably the serial signal of primary colors (for example RGB dot-sequential signal). Such high-speed A/D converter has drawbacks of large circuit structure and high power consumption, and, when used in combination with an A/D converter of a relatively low speed, it is extremely difficult to match the characteristics (reference voltage, nonlinearity etc.) of these A/D converters. Besides, the conventional circuit structure is inevitably complex because exclusive circuits are required for the signal compression at recording and for the signal expansion at reproduction. EP-A-0336317 discloses an electronic still camera which can be switched in order to record an image in a semiconductor memory, an optical memory or magnetic memory. Images are stored in a buffer memory and are sent via modulators to magnetic or optical memory or, after compression, to semiconductor memory. SUMMARY OF THE INVENTION An object of the present invention is to provide an image processing apparatus or an image transmitting apparatus capable of resolving the above-mentioned drawbacks totally or individually. Another object of the present invention is to provide an image processing apparatus or an image transmitting apparatus capable of achieving multiple functions with a simple structure. According to the present invention, there is provided image processing apparatus for use in a camera, comprising: converting means for converting an input image signal, photoelectrically converted from an object image, into another signal format different from the input image signal, based on a predetermined program; characterised in that the apparatus includes: first providing means for providing said converting means with a first program for converting said input image signal into a compressed signal; and second providing means for providing said converting means with a second program for converting said input image signal into a predetermined signal format, which format is suitable for storage in a storage medium; and control means for causing, in case of compressing said input image signal, said first providing means to provide said first program to said converting means, and for causing, in case of converting said input signal into a format suitable for being stored in said storage medium, said second providing means to provide said second program to said converting means. By this apparatus, separate circuits are not required for conversion into different signal forms and the entire circuit structure can be compactized. Still another object of the present invention is to provide a camera capable of A/D conversion of plural signals with a simple structure. Still another object of the present invention is to provide a camera capable of signal compression and expansion with a simple structure. According to another aspect, the invention provides a camera that includes the image processing apparatus of the invention. Still other objects of the present invention, and the features thereof, will become fully apparent from the following description of the embodiments, to be taken in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of an example of a camera not according to the present invention but for helping to understand the invention; Fig. 2 is a view showing the circuit structure of an image pickup device of the camera of Figure 1 and the arrangement of color filters; Fig. 3 is a view showing the order of data readout and data processing of a frame memory 22 of the camera at the image taking and recording; Fig. 4 is a chart showing the frequency allocation of the recording signal of a magnetic disk 48; Fig. 5 is a chart showing the DC level of a line-sequential color difference signal; Fig. 6 is a view showing the storage positions of output data of an image pickup circuit 14 in the frame memory 22 of the camera; Fig. 7 is a view showing the storage positions of signal reproduced from the magnetic disk 48 into the frame memory 22 of the camera; Fig. 8 is a block diagram of an embodiment of the present invention; and Fig. 9 is a view showing the details of a principal part of the embodiment shown in Fig. 8. DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a block diagram of an example of a digital camera, wherein provided are a phototaking lens 10; a diaphragm 12; an image pickup circuit 14 including a CCD image sensor device; a switch 16 for selecting either the output signal of the image pickup circuit 14, or an external or reproduced image signal; A/D converters 18, 20; a frame memory 22; a memory control circuit 24 for controlling the frame memory 22; a high speed arithmetic operation unit 26 for converting the stored data of the frame memory 22 into an output format; D/A converters 28, 29, 30; low-pass filters (LPF) 32, 33, 34 for removing the unnecessary band component generated by the D/A converters 28, 29, 30; an adder 36 for adding a synchronization signal to the brightness signal; frequency modulation circuits 38, 39; an adder 40; a recording amplifier 42; a recording/reproduction selector switch 44; a magnetic head 46; a magnetic disk 48; a head moving device 49 for moving the magnetic head 46 to a designated track position of the magnetic disk 48; a PG coil 50 for detecting the rotational phase of the magnetic disk 48; a motor 52 for rotating the magnetic disk 48; a servo circuit 54 for the motor 52; an NTSC encoder 56; and an image output terminal 57. There are further provided a reproducing amplifier 60; a band pass filter 62 for extracting the brightness component from the reproduced signal; a low-pass filter 63 for extracting the color difference components from the reproduced signal; frequency demodulating circuits 64, 65; an external image input terminal 66; an NTSC decoder 68 for separating the external image signal into a brightness signal and two color difference signals; a color difference level conversion circuit 70 for converting the color difference signals R-Y, B-Y into line sequential signals and converting the DC level of said color difference signals into a level defined in the still video format; a switch 72 for selecting the external image signal or the reproduced image signal; and a synchronization separating circuit 74 for separating the synchronization signal from the brightness signal selected by the switch 72. There are further provided a system control circuit 76 for controlling the entire system; a standard signal generator (SSG) circuit 78 for supplying reference signals to various units; a switch box 80 for entering various operation commands to the system control circuit 76 and including a shutter switch 81, a release switch 82, a record/reproducing switch 83, an input video switch 84, a track forwarding switch 85, a track reversing switch 86 and transmission switch 87; a battery 88 for supplying electric power to various units; a low-pass filter 90; a transmitting amplifier 91; an acoustic coupling terminal 92; and a low-pass filter 93. At first there will be explained the recording (phototaking) operation of the apparatus shown in Fig. 1. When a shutter release button is lightly depressed, the release switch 82 is closed, and the shutter switch 81 is then closed upon further depression. The closing of the release switch 82 is transmitted through the switch box 80 to the system control circuit 76, which in response starts the power supply to the image pickup circuit 14, A/D converters 18, 20, standard signal generator 78, frame memory 22, memory control circuit 24, servo circuit 54 and motor 52. The standard signal generator 78 provides, based on a PG signal from the PG coil 50, the servo circuit 54 with a reference signal constituting a reference for the rotation of the magnetic disk 48, and the servo circuit 54 controls the rotation of the motor 52 based on said reference signal and an FG signal from the motor 52. Then, in response to the closing of the shutter switch 81, the diaphragm 12 is so controlled as to obtain an appropriate exposure, and the image pickup circuit 14 accumulates charges, corresponding to the light coming from an object, for a predetermined period. Said charges are read by clock signals from the standard signal generator 78. Fig. 2 shows the circuit structure of the image pickup circuit 14 and the filter arrangement of the photoelectric conversion device. These structures will not be explained in detail since they are already known. The output of the image pickup circuit 14 is supplied through the switch 16 to the A/D converter 18, digitized therein and stored in succession in the frame memory 22. When the rotation of the magnetic disk 48 becomes stabilized at a predetermined value, the servo circuit 54 sends a servo locking signal to the system control circuit 76, which in response activates the high-speed arithmetic operation circuit 26, thereby releasing the stored data of the frame memory 22 with conversion to the recording format for the magnetic disk 48. More specifically, the pixel data stored in the frame memory 22 in the order of color filter arrangements of the photoelectric conversion device of the image pickup circuit 14 as shown in Fig. 3 are converted into brightness data Y and color difference data R-Y, B-Y, utilizing an odd line and an immediately succeeding line in a first field as indicated by a solid line, or utilizing an even line and an immediately succeeding line in a second field as indicated by a broken line. Thus, in the first pixel in the first field, there are obtained: Y 00 = K 1 G(P 01 ) + K 2 R(P 00 ) + K 3 B(P 10 ) (R-Y) 00 = R(P 00 ) - Y 00 (B-Y) 00 = B(P 10 ) - Y 00 and, in the second pixel there are obtained: Y 00 = K 1 G(P 01 ) = K 2 R(P 00 ) + K 3 B(P 10 ) (R-Y) 00 = R(P 00 ) - Y 00 (B-Y) 00 = B(P 10 ) - Y 00 wherein K 1 = 0.59, K 2 = 0.3 and K 3 = 0.11, and P ij is the address of the frame memory 22 (cf. Fig. 3). The brightness data obtained in the high-speed arithmetic operation unit 26 are supplied to the D/A converter 29, while the color difference data R-Y, B-Y are alternately, by every line, to the D/A converter 30. The conversion frequencies of the D/A converters 29, 30 are determined by the recording frequency band of the magnetic disk 48. The outputs of the D/A converters 29, 30 are subjected to elimination of the unnecessary band component by the low-pass filter 33, 34, then to addition of the synchronization signal to the brightness signal in the adder 36, and are frequency modulated in the modulation circuits 38, 39. Fig. 4 shows the frequency allocation of the brightness signal and the color difference signals. The brightness signal and color difference signals subjected to frequency modulation are frequency multiplexed in the adder 40, then amplified by the recording amplifier 42 and supplied to the magnetic head 46 for recording on the magnetic disk 48. Upon recording of an image, the system control circuit 76 moves the magnetic head 46 by a head carrier 49 to the inside, and awaits the next phototaking operation. If the release switch 82 is closed in this state, the motor 52 is maintained in rotation. If said switch is open, the motor 52 is stopped and the power supply to the circuits 14, 18, 20, 22, 26, 28, 29, 30, 38 and 39 are interrupted. In the following there will be explained the reproducing operation of the image recorded on the magnetic disk 48. When the record/reproduction switch 83 is shifted to the reproduction side, the reproduction mode is assumed, whereby the switches 44, 72 are both connected to contacts b. The reproduction output from the magnetic head 46 is supplied through the switch 44 and the reproducing amplifier 60 to the band-pass filter 62 and the low-pass filter 63, thereby being separated into a modulated brightness signal and modulated color difference signals. Said signals are demodulated by the frequency demodulating circuits 64, 65 into the brightness signal and the color difference signals of base band, which are supplied through the switch 72 to the A/D converters 18, 20, digitized therein and stored in the frame memory 22. The synchronization separating circuit 74 separates, from the demodulated brightness signal, the horizontal and vertical synchronizations signals, which are supplied to the standard signal generator 78 and the system control circuit 76. The system control circuit 76 sends a command to the standard signal generator 78 for releasing a timing signal, for determining the timing of data fetching of the frame memory 22, and the memory control circuit 24 provides the A/D converters 18, 20 with a conversion timing signal synchronized with the horizontal synchronization signal H and the vertical synchronization signal V separated by the synchronization separating circuit 74. Also the memory control circuit 24 sends write-in addresses to the frame memory 22, under the control by the control signal from the standard signal generator 78. During the fetching of image data of a frame into the frame memory 22, the D/A converters 28, 29 and 30 are muted. The A/D converter 20 receives line-sequential color difference signals, with different DC levels in the R-Y and B-Y components as shown in Fig. 5. These signals are simply digitized in the A/D converter 20 and stored in the frame memory 22. The R-Y component and B-Y component can be distinguished, according to the DC level thereof, by the high-speed arithmetic operation circuit 26 either at the recording into the frame memory 22 or the reading from the frame memroy 22. At the phototaking operation, the frame memory stores the pixel data from the image pickup device in the order of output therefrom as shown in Fig. 6, but, at the reproducing operation from the magnetic disk 48, said memory stores the signals in the form of brightness signal and line-sequential color difference signals as shown in Fig. 7. Upon completion of the data fetching into the frame memory 22, the standard signal generator 78 sends a timing signal for starting arithmetic operation to the high-speed arithmetic operation circuit 26, which sends the brightness data of the frame memory to the D/A converter 29, the line-simultaneous color difference data B-Y to the D/A converter 28, and the line-simultaneous color difference data R-Y to the D/A converter 30. Said D/A converters 28, 29, 30 converts said data into analog signals, according to a conversion clock signal from the high-speed arithmetic operation circuit 26. Naturally there may be employed independent clock signals matching the bands of said data. Thus obtained analog brightness and color difference signals are subjected to elimination of the unnecessary band component by the low-pass filters 32, 33, 34, then to addition of the synchronization signal to the brightness signal by the adder 36, and are converted into an NTSC video signal by the NTSC encoder 56, of which output is supplied, through the output terminal 57, to an external monitor unit. In the following there will be explained the operation of recording an external image signal on the magnetic disk 48. In this case, in response to the input video switch 84, the switches 44, 72 are both connected to the contacts a . The image signal entered into the external image input terminal 66 is separated, by the NTSC encoder 68, into a brightness signal including synchronization signals, and color difference signals R-Y, B-Y. Said color difference signals are converted into line-sequential signals with predetermined DC offsets, as in the recording onto the magnetic disk 48, by the color difference level conversion circuit 70. The brightness signal from the NTSC decoder 68 and the line-sequential color difference signals from the color difference level conversion circuit 70 are supplied, respectively through the switches 72, 16, to the A/D converters 18, 20. When the shutter release button is depressed in this state, the release switch 82 is closed to power the A/D converters 18, 20, frame memory 22, memory control circuit 24, motor 52 and servo circuit 54, thereby rotating the magnetic disk 48. Then in response to the closing of the shutter switch 81, the memory control circuit 24 supplies the A/D converters 18, 20 with conversion clock signals and the frame memory 22 with a write-in signal and a write-in address signal, whereby the signals are stored in the frame memory 22 as shown in Fig. 7. When the rotation of the magnetic disk 48 becomes stabilized, the servo circuit 54 provides the system control circuit 76 with a servo locking signal, whereby the high-speed arithmetic operation circuit 26 is activated to send the brightness data to the D/A converter 29 and the line-sequential color difference data to the D/A converter 30. Thereafter signal recording on the magnetic disk 48 is conducted in the same manner as in the phototaking and recording operation. In the following there will be explained the operation of transmitting image data stored in the frame memory 22. In case of phototaken image data, data of each pixel are stored in the frame memory 22 as shown in Fig. 6. At first data of each color is subjected to data compression by one-dimensional ADPCM. Then the D/A converter 28 is used as a digital modulator to effect QAM, and the data are transmitted to a public telephone line through the low-pass filter 90, amplifier 91 and acoustic coupling terminal 92. The data read-out from the frame memory 22 is conducted, for example, in the following order: Red: P 00 , P 11 , P 03 , P 04 ,... Green: P 01 , P 12 , P 04 , P 15 ,... Blue: P 10 , P 02 , P 13 , P 05 ,... Also in case of transmitting the image signal reproduced from the magnetic disk 48 or the external image signal entered from the external input terminal 66, the frame memory 22 stores the data of each pixel as shown in Fig. 7. At first the brightness signal and the color difference signals are separately subjected to data compression by one- or two-dimensional ADPCM, and the data are transmitted to the telephone line by QAM modulation as explained above. The signal received from the telephone line is supplied through the low-pass filter 93 to the A/D converter 94 for digitization therein. The reference voltage of the A/D converter 94 is supplied from the output of the D/A converter 30, and is made lower or higher respectively when the received signal level is low or high, thereby expanding the dynamic range of the A/D converter 94. This adjustment is completed before the reception of the image data. Upon completion of said adjustment, a QAM demodulating circuit in the high-speed arithmetic operation circuit 26 is activated to demodulate the received signal. The signal is further subjected to ADPCM demodulation, and stored in succession in the frame memory 22. The kind of the image data, namely RGB data, brightness-color difference data, or NTSC video data, can be distinguished from control data to be transmitted prior to the image data. In the foregoing a magnetic disk is taken as an example of the recording medium, but it is naturally possible to use a magnetooptical disk, an IC card or a magnetic tape. The present embodiment enables to compactize the entire circuit structure, by effective utilization of the image memory at recording, reproduction and transmission. Also the present embodiment allows to reduce the electric power consumption and to stabilize the reproduced image, since the recording medium need not be continuously drive at the image reproduction. Also the manufacturing cost can be reduced since the line sensing circuit is not required for the reproduction of the signal recorded on the recording medium. Furthermore, the memory control circuit 24 is provided with first readout means for displaying the data stored in the image memory means as a visible image and second readout means for data reading according to the transmission capacity of the transmission channel, but it is also possible to utilize a separate read-out circuit. Also D/A converters are employed for converting the data read from the image memory means, but there may be employed other circuits, such as a look-up table for tonal conversion or a color correcting table. Figure 8 shows an embodiment of the present invention, which is a variation of the embodiment shown in Fig. 1. In said variation there are additionally provided ROM's 1100, 1101 and a connector 1092 for storing the output of the high speed arithmetic operation unit 6 in a recording medium provided in an IC card 1090. The ROM 1100 stores an algorithm for data compression of a high compression rate (for example a compression algorithm utilizing orthogonal conversion) to be conducted at the data transfer from the high-speed arithmetic operation circuit 26 to the IC card 1090. Said ROM 1100 also stores an algorithm for processing the output signal from the image pickup device 114, and an algorithm for processing the output signal from the magnetic disk 148. Also the ROM 1101 stores an algorithm for forming the line simultaneous signal matching the NTSC format from the image data shown in Fig. 7, at the data output to the NTSC encoder 56. Also the high speed arithmetic operation circuit 26 is provided, as shown in Fig. 9, with latch circuits 1120, 1122, 1124 for respectively latching the brightness signal and color difference signals R-Y, B-Y released from an input unit for receiving the signal read from the memory 22 or from a digital signal processor (DSP) 1110. There are also provided an output port 1126 for causing the IC card 1090 to release highly compressed data; a program RAM 1112 for storing the program transferred from the ROM 1100 or 1101 shown in Fig. 8, under the instruction from the system control unit 176; and a work area 1114 to be utilized in the data processing in the DSP 1110. In the present embodiment, the DSP 1110 can execute various processes according to the programs read from the ROM's 1100, 1101. Therefore, in case of data storage into the IC card 1090 mounted on the main body of the apparatus, said data storage is achieved by data compression, such as orthogonal conversion, according to a program stored in the ROM 1101. Also in the present embodiment, since the high-speed arithmetic operation circuit is composed of a digital signal processor as shown in Fig. 9, desired processes can be executed by merely replacing the ROM's 1100, 1101 with other ROM's storing other programs. References to DSP in the foregoing will be understood to indicate, but not be limited to, digital signal processing (DSP) devices such as the Western Electric DSP 32 single chip digital device available from AT&T, and the various block diagrams supplied will be understood to indicate the function, rather then the internal architecture, of the device. References to NTSC in the foregoing will be understood but by way of example only; the skilled man will immediately perceive how the invention may be applied to PAL or SECAM systems, or to high definition television image format systems, existing or future.

Claims: Image processing apparatus for use in a camera, comprising: converting means (126) for converting an input image signal, photoelectrically converted from an object image, into another signal format different from the input image signal, based on a predetermined program; characterised in that the apparatus includes: first providing means (1100,1101) for providing said converting means with a first program for converting said input image signal into a compressed signal; and second providing means (1100,1101) for providing said converting means with a second program for converting said input image signal into a predetermined signal format, which format is suitable for storage in a storage medium; and control means (176) for causing, in case of compressing said input image signal, said first providing means to provide said first program to said converting means, and for causing, in case of converting said input signal into a format suitable for being stored in said storage medium, said second providing means to provide said second program to said converting means. Apparatus according to claim 1, further comprising means for storing the image signal, following conversion into the predetermined format suitable for a storage medium, in a storage medium. Apparatus according to claim 1 or 2, further comprising means for generating said image signal. Apparatus according to claim 3, wherein said generating means comprises an image pickup device (14, 114) for converting an object image into an image signal. Apparatus according to any preceding claim, wherein said input image signal is a dot-sequential color image signal of red, green and blue. Apparatus according to claim any preceding claim, wherein said compression process includes an orthogonal conversion process. Apparatus according to any preceding claim, further comprising means for storing the compressed image signal in a semiconductor memory medium (1090). Apparatus according to any preceding claim, wherein said first providing means comprises a read-only memory. A camera that includes the apparatus of any preceding claim.

Inventors: KONDO MAKOTO, MIMURA TOSHIHIKO, OHARA EIJI, TAGUCHI TOMISHIGE, KONDO, MAKOTO, MIMURA, TOSHIHIKO, OHARA, EIJI, TAGUCHI, TOMISHIGE, KONDO, MAKOTO, C/O CANON KABUSHIKI KAISHA, MIMURA, TOSHIHIKO, C/O CANON KABUSHIKI KAISHA, OHARA, EIJI, C/O CANON KABUSHIKI KAISHA, TAGUCHI, TOMISHIGE, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1990
Main classification: H04N1
IPC codes: H04N1, H04N9