JPH04151994A - Electronic still camera - Google Patents

Abstract

PURPOSE:To realize the electronic still camera compatible with each TV system by means of the electronic still camera only by unifying a recording format, conversing scanning lines and switching each color modulation system at the reproduction. CONSTITUTION:A picture is fetched with scanning lines (626 lines, 25Hz) equivalent to those for the PAL, SECAM systems, the picture is compressed and recorded, and scanning lines area thinned at reproduction to allow the camera to be compatible with the NTSC (252 lines, 30Hz) system. That is, a same memory 6 for one screen is provided and a signal read from the memory 6 at reproduction is thinned at a rate of one line per 6 lines and two oscillators for chrominance subcarrier and two BPFs are provided for the modulation of a color difference signal and a changeover switch 17 is used to select any of the two color modulation systems. Through the constitution above, even when a memory card format to be recorded is recorded equally, the picture is observed by using television receivers of the different systems. Moreover, manufactures for electronic still cameras need not to manufacture electronic still cameras exclusive for a specific TV system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronic still video camera such as a digital still video camera having an image compression/expansion process.

(Prior Art) Conventionally, electronic still cameras that rely on television systems use NTSC (Nat
ional Te]evision SystemCo
mmi ttee), P A L (Phase Al
ternation byL 1ne), S E CA
M (Sequer+tial and memo
ry), and the number of scanning lines differs (N T S C = 525 lines, PAL, SECAM =
625 cameras), different frame frequencies and different color modulation methods, and electronic still cameras compatible with each method were used.

(Problem to be Solved by the Invention) However, when using an electronic still camera compatible with a television system as described above, when traveling overseas, the screen shot with an NTSC camera is
The problem was that it could not be seen on AL television. Furthermore, manufacturers of electronic still cameras have to manufacture cameras compatible with each television system.

The present invention solves the above-mentioned conventional problems, and aims to provide an electronic still camera that can support each television system with a single camera.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electronic still camera with PAL and SECAM (7) scanning lines (625 lines).

25Hz), compresses and records the image, thins out the scanning lines during playback, and converts the image to NTSC (525 lines, 30Hz).
) system. That is, it has a frame memory for one screen, thins out the readout from the frame memory at a rate of 1 line every 6 lines during playback, and has two color subcarrier oscillators for modulating color difference signals. It has two bandpass filters, and the two color modulation methods can be switched using a changeover switch.

(Function) Therefore, according to the present invention, the recording format is set to NTS.
C, PAL, SECAM, etc. are all unified note-repino television systems, and since they have scanning line conversion and modulation methods for each color, even if the memory card format is - , can also be viewed on different television systems.

(Embodiment) FIG. 1 shows a block configuration of an electronic still camera according to an embodiment of the present invention. In FIG. 1, 1 is a lens, 2 is an aperture that narrows down the amount of light, and 3 is an image sensor,
The formed image of the subject is photoelectrically converted into an electrical signal. 4 is a process circuit that performs color signal processing, γ correction, etc.;
5 is an A/D converter, 6 is a frame memory, 7 is an image signal compression/expansion circuit, 8 is a memory controller, 9 is a connector, IO is a D/A converter, 11 is an addition circuit, 1
2 is an encoder, 13 is an oscillator, 14 is an output terminal, 15
1 is an address controller that thins out every 6 lines by 1 line, 16 is a pulse generator, 17 is a changeover switch, 100 is an electronic still camera having the above 1 to 17, and 200 is a memory card.

Next, the operation of the above embodiment will be explained. An image of a subject captured by a lens 1 is focused to an appropriate amount of light by an aperture 2 and formed on an image sensor 3. Here, the image of the subject is photoelectrically converted and output as an electrical signal. The specifications of the image sensor 3 are 62
There are 5 lines and 25H2, which corresponds to PAL scanning lines.

The output of the image sensor 3 is input to a process circuit 4, where it undergoes processing such as color signal processing and γ correction, and is output as component signals of a luminance signal (Y), two color difference signals (R-Y), and (B-Y). Ru. Each of these component signals is converted into a digital signal by an A/D converter 5 and temporarily held in a frame memory 6. The output from the frame memory 6 is read out in block units (e.g., 8×8 pixels) necessary for the next stage of image compression according to the address from the address controller I5, and is sent to the compression/expansion circuit 7 to perform, for example, adaptive discrete cosine transformation. ADCT) process image is compressed and written to a memory card 200 connected to a connector 9 via a memory controller 8.

During playback, compressed image data of a predetermined screen is read from the memory card 200 by the memory controller 8, the image data is expanded block by block by the compression/expansion circuit 7, and sequentially written into the frame memory 6. Then, image data is read out from the frame memory 6 for each scanning line, and the D/A
Each is output as an analog component signal by the converter 10, and a synchronization signal is output from the pulse generator I6.

The burst signal and the blanking signal are added in the adder circuit 11, and the video encoder 12 balance-modulates the color difference signal into a color signal using the color subcarrier (4,43MH7,) from the oscillator 13, and generates a composite video signal (PAL). Output from the output terminal. When playing, turn the selector switch 17 to N.
When set to the TSC side, an operation of thinning out one line out of every six lines when reading from the frame memory 6 is performed using the read address from the address controller 15. This situation is shown in FIG. That is, as shown in FIG. 2(a), the frame memory 6 has horizontal lines 720. It has a vertical pixel configuration of 576, which is thinned out by one out of every six pixels, and the second
Horizontal 720. as shown in figure (b). 480 vertically, but in order to read out from the frame memory 6 in a filled sequence and perform non-interlace-interlace conversion, the odd field is 1°3.5 as shown in FIG. 2(c).
, 2, 4. ...and the even field is 2, 4
, 1, 3, 5. . . . to perform scan line thinning and non-interlace/interlace conversion. In the next addition circuit 11, the output pulse from the pulse generator 16 is switched depending on the PAL and NTSC modes, and a synchronization pulse suitable for each mode is output.

FIG. 3 shows a block configuration of a color encoder in an embodiment of the present invention. In Figure 3, 17
is a changeover switch, 21 is a color difference signal (RY) terminal, 22
are color difference signal (B-Y) terminals, 23° and 24 are burst addition circuits, 25.26 are balanced modulation circuits, 27 are selector switches, 28 are oscillators (A), 29 are oscillators (B), and 30 are addition circuits. , 31.32 is a changeover switch, 33 is a band pass filter (A) (B P F (A)), 34 is B
P F (B), 35 is an output terminal.

Next, the operation of the color encoder will be explained. Color difference signals (RY) input from terminals 21 and 22, (B-
Y) adds burst gate pulses by burst addition circuits 23 and 24. At this time, in the case of NTSC, only the color difference signal (B-Y) is used, and in the case of PAL, the color difference signal (R-
Y) and (B-Y) are both added. Next, each color difference signal is balanced modulated by balanced modulation circuits 25 and 26 at 4.43 MHz for PAL and 3.58 MHz for NTSC. At this time, the carrier waves are inputted to two balanced modulation circuits by switching the outputs from the oscillator (A) 28 and oscillator (B) 29 using a changeover switch 27. Oscillator (A)
is a PAL oscillator with an oscillation frequency of 4.43 MI (z).The input carrier wave of the color difference signal (RY) to the balanced modulation circuit 25 has a phase inverted every horizontal scanning line.The oscillator (B
) 29 outputs carrier waves whose phases are 0° and 90°. Next, an adder circuit 30 adds the outputs of the two balanced modulation circuits 25 and 26.
Add with . The output of the adder circuit 30 needs to be passed through a BPF to remove unnecessary components.
P F (A)33. B P F (B) has 34, B P F (A) 33 is 4.43 MF (BPF of z
, and B P F (B)34 is a 3.58 MHz BPF. By switching the changeover switches 31 and 32, the two BPFs are switched in conjunction with the PAL/NTSC changeover switch 17, and an encoded color signal is output from the output terminal 35.

(Effects of the Invention) As is clear from Example 1, the present invention uses the recording format of an electronic still camera as NTSC.

There are no differences between the television system systems such as PAL and SECAM, and the electronic still camera has the same scanning line conversion and color tone modulation methods during playback, so the recorded memory card format is the same. This has the effect that even if it is recorded, it can be viewed on a television set with a different system. This also has the effect that manufacturers of electronic still cameras do not have to manufacture electronic still cameras compatible with television systems.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electronic still camera according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of an address controller when reading a frame memory, and FIG. 3 is a block diagram of an encoder according to an embodiment of the present invention. . DESCRIPTION OF SYMBOLS 1...Lens, 2...Aperture, 3...Photographing element, 4...Process circuit, 5...A/D converter, 6...Frame memory, 7...
compression/expansion circuit, 8... memory controller, 9
...Connector, 1.0...D/A converter,
I+, 30・addition circuit, 12...encoder,
13・Oscillator, 14.35・Output terminal, 15...
Address controller, 16... Pulse generator, 17.27.31°32... Changeover switch, 2
1... Color difference signal (RY) terminal, 22... Color difference signal (B-Y) terminal, 23.24... Burst addition circuit, 25°26... Balanced modulation circuit, 28...
Oscillator (A). 29...Oscillator (B), 33...B P F (
A), 34...B P F (B).

Claims (2)

[Claims] (1) An electronic still camera that has an image compression/decompression process has a frame memory for one screen, and an address controller controls the reading from the frame memory during decompression (during playback) so that one line out of every six lines is thinned out. It also has two color subcarrier oscillators and two bandpass filters (BPF) for modulating color difference signals, and can switch between two color modulation methods using a changeover switch. An electronic still camera that is characterized by the ability to (2) In an electronic still camera that has an image compression/expansion process, a lens, an aperture, an image sensor that outputs an electric signal corresponding to a PAL scanning line, and a process circuit that performs color signal processing, γ correction, etc. An A/D converter, a frame memory, an image compression/expansion circuit, a memory controller, a D/A converter, an address controller,
A pulse generator, an adder circuit, two oscillators,
The electronic still camera according to claim 1, further comprising an encoder and a PAL/NTSC changeover switch.