JPH0250579A - Electronic still camera - Google Patents

Abstract

PURPOSE:To temporarily display the contents of a photographed still picture on a finder by providing a picture signal continuously image picked up before an exposure so that the still picture signal of a memory means may be supplied only for a prescribed period after the exposure. CONSTITUTION:The output of a solid-state image pickup element 30 is changed over by a switch 4, and supplied through a recording system or a system separately provided from the recording system to an electronic view finer 10. The recording system includes a signal processing circuit 5, and records a respectively signal-processed picture signal to a recording medium 6. On the rear stage of the signal processing circuit 5, a frame memory 7, which can store only the still picture signal for one field out of the surface-successively outputted color picture signal is separately provided from the recording system. The frame memory 7 consists of rewritable memories, and a memory output is supplied to the electronic view finder 10. Thus, the picture recorded while having the frame memory can be monitored in the finder as the still picture after the photographing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electronic still camera, and more specifically, it is equipped with an electronic viewfinder and can display recorded images actually taken on the electronic viewfinder. Regarding electronic still cameras.

(Prior Art) Recently, electronic still cameras equipped with electronic viewfinders have been proposed, similar to video cameras.

This electronic viewfinder supplies image signals output from a solid-state image sensor to an external or built-in small monitor or television to display the image, and is used in movie mode when determining shooting conditions. This generally makes it easier to set the angle of view.

(Problem to be Solved by the Invention) However, on the other hand, when the electronic viewfinder is applied to an electronic still camera, since the electronic still camera takes one shot screen, if the screen is not fixed in movie mode, This has the disadvantage that it is difficult to accurately determine the angle of view when actually taking a picture with the shutter open. In particular, it was difficult to accurately determine the angle of view for moving subjects.

Also, if you try to check the images actually taken and recorded with a conventional electronic still camera by displaying them on the viewfinder,
It was necessary to play back the disc on which the images were recorded, which was time-consuming and required an increase in the size of the device.

In other words, it is difficult to check photographing conditions such as angle of view setting, exposure, and focus adjustment using the electronic viewfinder by taking a trial shot.

An object of the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electronic still camera that can temporarily display the contents of a photographed still image on a viewfinder without playing back a recorded medium. .

(Means and Effects for Solving the Problems) The above-mentioned object of the present invention is to convert an image signal into a plane in an electronic still camera consisting of a solid-state image sensor in which a dark box, an imaging optical system, a shutter, a recording medium, and a color filter are arranged. A solid-state image sensor that sequentially outputs image signals, a recording system that records image signals output after exposure on a recording medium, an electronic vinyl finder that displays the captured subject image on a screen, and an image signal that outputs image signals after exposure. A rewritable memory means for storing at least one field worth of still image signals, and an image signal continuously captured by opening the shutter before exposure, and a still image signal stored in the memory means are switched to the viewfinder. and a switch means for sending a continuously imaged image signal to the viewfinder before exposure, and a still image signal from the memory means for a predetermined period after exposure. This is achieved by an electronic still camera that is characterized by

Note that the present inventors have already proposed a solid-state imaging device that can improve sensitivity and resolution when applied to electronic still cameras.

In this solid-state image sensor, the vertical charge transfer section has a photoelectric conversion function at the same time as charge transfer, and a color filter of one color is arranged on the vertical charge transfer section, and two color filters are arranged on the photosensitive area.
Color filters are arranged so that image signals of three colors are output in a frame-sequential manner.

Particularly, when an electronic vinyl finder is used to monitor photographed images as in the present invention, the image information manually input to the finder is sufficient for one screen of light or several hundred pixels or less. Furthermore, it is convenient to use a frame-sequential solid-state image pickup device because a monochrome screen is sufficient and a wide range can be compressed.

The shutter is opened to take a picture, and among the image signals output from the solid-state image sensor in a frame-sequential manner, for example, one field's worth of signals is subjected to appropriate signal processing and signal compression. By storing the image in the image memory and sending it to the electronic viewfinder after exposure, the actual photographed image can be monitored.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

One embodiment of FIG. 1 conceptually shows an electronic still camera according to the present invention.

In the figure, this electronic still camera incorporates an imaging optical system 2 and a shutter 3 in a dark box 1, similar to a conventional silver halide film camera. The image of the subject incident through the imaging optical system 2 and the shutter 3 is captured by a solid-state imaging device 30, which will be described later, and is output as a photoelectrically converted image signal.

The solid-state image sensor 30 is configured as shown in FIG. 2, and outputs color image signals of three primary color components in a frame-sequential manner. That is, this solid-state image sensor 30 has a photoelectric conversion function by disposing a micro color filter similar to the photoelectric conversion section 31 also on the vertical transfer path 32 of the interline transfer CCD.

Then, by controlling the transfer gate Tg formed between the vertical transfer path 32 and the photoelectric conversion section 31, the vertical transfer path 3
2 and the photoelectric conversion unit 31 are sequentially vertically transferred by the transfer electrodes 33 to 36, and then transferred to the transfer gate 37.
The image signals are sequentially output from one horizontal CCD 38 as RGB color-separated image signals.

In this embodiment, green and blue filters indicated by symbols G and B are arranged alternately in the vertical direction on the surface of each photoelectric conversion element constituting the photoelectric conversion unit 31, and vertical transfer paths On the surface of 320, red filters indicated by symbol R are arranged in stripes.

Further, the transfer electrodes 33, 34, 35, 36 are provided in a set of 4 and are controlled by the vertical transfer control unit 39, and the 4-phase drive φ1
~φ, has been done.

Returning to FIG. 1, the output of the solid-state image sensor 30 is switched by a switch 4 and supplied to the electronic viewfinder 10 via a recording system or a system provided separately from the recording system. . The recording system includes a signal processing circuit 5, and outputs image signals subjected to various signal processing to a recording medium 6,
This embodiment is configured to record on a floppy disk.

At the subsequent stage of the signal processing circuit 5, a frame memory 7 is provided as a recording system, which can store only one field of still image signals of the color image signals outputted in a frame-sequential manner, in this embodiment, only image signals corresponding to color R. It is set up separately. The frame memory 7 is a rewritable memory, for example, a RAM (
It consists of random access memory) and EEPROM (electrically erasable read-only memory).
The memory output is adapted to be supplied to the electronic viewfinder 10.

Here, ■The still image for the field only needs to have the information necessary to confirm the shot image, and the signal is compressed to a higher degree than the image signal sent to the recording medium, and the memory capacity of the rewritable memory is can be made smaller. Also,
Images can be displayed two-dimensionally on an electronic viewfinder without being restricted by the format recorded on a recording medium (floppy disk, memory card, etc.).

The solid-state image sensor 30, switch 4, signal processing circuit 5, and frame memory 7 are controlled by a synchronization signal from a synchronization signal generator 8.

Next, the operation of the electronic still camera will be described with reference to FIG. 3 showing the driving timing of the solid-state image sensor applied to the present invention.

Time t0 indicates the start of use when the power switch of this camera is turned on, and the camera is at time t.

to t3, the monitor mode is set.

In this monitor mode, the shutter control signal S2 is “H”
The shutter 3 shown in FIG. 1 is always in an open state by inverting the level, and the switch 4 is connected to the monitor/TV side so that the image signal of the subject imaged by the solid-state image sensor 30 is continuously monitored/TV. supply to. Therefore, the charge accumulated in the element between time to %t is
The data is vertically transferred between times t1 and t2 and repeatedly read out on a monitor or television.

That is, time t. At drive signal φ8. φ2゜φ
3 first goes to "H" level, and the drive signal φ goes to "L" level, so that the corresponding transfer electrode 33.3 goes to "L" level. A potential well is formed in the charge transfer element below 34°35.

Next, drive signal φ1. By bringing φ3 to a higher level "H", the transfer gate Tg becomes conductive, and the signal charges of colors G and B generated in the photoelectric conversion section 31 are transferred to the potential well below the transfer electrode 33, 35. . As a result, the color R signal charges generated in the potential well and the color G and B signal charges generated in the photoelectric conversion section 31 are mixed and stored in the potential well. Further, only the drive signal φ2 is maintained at the "H" level, so that the mixed signal charges are collected in the potential well below the transfer electrode 34, and the signal charges of each color are mixed.

Next, time 1. The mixed signal charges are output according to the timing based on the well-known four-phase drive blade system, and the output signal is supplied to the viewfinder monitor/television 10.

The operation of reading signal charges for one frame from time t0 to t2 (operation during period T in the figure) is repeated until the shutter release is pressed. By setting this repetition period to 30 frames per second as in the NTSC system, it becomes possible to set the angle of view while observing the movement of the subject. Incidentally, when performing readout at such a period, the signal charge mixing process from time t0 to time t is performed within a so-called blanking period.

Next, when the shutter release is pressed at time t3, the camera enters the shooting mode, and the shutter control signal S,
is reversed to the "L" level and the shutter closes. As the shutter closes, the same operation as from time to to t2 is performed once, and unnecessary charges remaining in the solid-state image sensor are discharged to the outside. When this unnecessary charge is discharged,
Set period T from time t4.

During this period T5, the drive signal φ2. φ3 is “H”, φ1. By setting φ4 to the "L" level, signal charges of color R are generated in the charge transfer elements below the transfer electrodes 33 and 34, and signal charges of colors G and B are generated in the photoelectric conversion section 31. Then, at the same time as the set period Ts ends, the camera switches to the read/record mode.

At the same time as the camera switches to the read/record mode, the switch 4 is switched to the recording system side. Then, the solid-state image pickup device outputs signal charges of each hue according to a so-called field-sequential reading method, and records the color video signal for one frame on the floppy disk 6. At this time, only the signal charges for one field of color R from the vertical transfer path 32 that are outputted first are stored in the frame memory 7 after being subjected to signal processing.

The signal charge of color R stored in this frame memory is output at the time when the signal charges of other colors G and B start vertical transfer, and is supplied to a monitor/television to display a still image. That is, this still image is based on photographing conditions that match the image actually recorded on the floppy disk, thereby confirming the photographed image. still,
The display period of this still image can be set until it is displayed after a predetermined period of time has elapsed or until the shank button is operated. Then, when the photographing ends (time ts), time t returns. It becomes a monitor mode from t2 to t2.

(Effects of the Invention) As described above, according to the electronic still camera of the present invention, an image recorded with a frame memory can be monitored as a still image in the viewfinder after shooting. , A, and E can be easily confirmed. Furthermore, since captured images can be recorded in a frame memory that can be rewritten independently of the format of the image information recorded on the recording medium, the driving method of the electronic vinyl finder can be optimized and at the same time the driving circuit can be simplified (HDTV, I
There are DTV, etc., but it is not influenced by these systems. )can. Furthermore, compared to the case where a reproduction process is used, the apparatus can be made smaller and easier to handle, and trial shots can be taken.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronic still camera according to an embodiment of the present invention, FIG. 2 is a block diagram of a solid-state image sensor applied to the electronic still camera of FIG. 1, and FIG. 3 is an operation of the electronic still camera. FIG. 2 is a drive timing diagram of an element for explaining. 1: Dark box, 2: Imaging optical system, 3: Shutter,
4: Switch, 5 Signal processing circuit, 6: Floppy disk, 7: Frame memory, 10: Monitor
Television, 30: Solid-state image sensor, 31: Photoelectric conversion unit, 32
: Vertical transfer path, 33 to 36: Transfer electrode, 38: Horizontal CCD. R: Red filter, G: Green filter, B: Blue filter

Claims (1)

[Claims] An electronic still camera consists of a solid-state image sensor that has a dark box, an imaging optical system, a shutter, a recording medium, and a color filter. a recording system for recording on a recording medium, an electronic viewfinder for displaying a captured subject image on a screen, and a rewritable memory means for storing at least one field worth of still image signals among the image signals output after exposure; a switch means for switching between an image signal that is continuously imaged by opening the shutter before exposure and a still image signal stored in the memory means and sending it to the viewfinder; An electronic still camera characterized in that the still image signal stored in the memory means is provided to the viewfinder for a predetermined period after exposure.