JP2500808Y2 - Electronic still camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Utilization of the Invention] The present invention relates to an electronic still camera, and more particularly to an electronic still camera having a function of notifying distance / distance information of a subject in portrait mode.

[Background of the invention]

Recently, a magnetic sheet that rotates by photographing a subject purely electronically by combining an image pickup device such as a solid-state image pickup device and a pickup tube with a recording device that uses a magnetic sheet that is inexpensive and has a relatively large storage capacity as a recording medium. An electronic still camera system for recording and reproducing images on a separate television system or printer has been developed and attracts attention.

By the way, it has been found that such an electronic still camera has the following problems due to its structure. That is, in the electronic still camera, the degree of integration of the charge-coupled device for capturing a subject image is still low even with the current integrated circuit forming technology, and the image resolution is insufficient. Also, the reproduction of the captured image is performed by a television (hereinafter abbreviated as TV).
The resolution of the image has a great influence on the number of pixels and the number of scanning lines of the TV screen. For this reason, when shooting with an electronic still camera, it is necessary to fully consider the shooting size of the subject, as will be described later.

In general, the proportion of faces in the shooting background in portrait shooting tends to be as follows. That is, FIG. 5 shows a photographic print, in which L represents the size in the vertical direction and H represents the size of the face. FIG. 6 is a diagram in which the ratio H / L occupied by the face in the photographic print shown in FIG. 5 is plotted on the horizontal axis, and the frequency at which the ratio H / L occurs is plotted on the vertical axis.
As is clear from the figure, in general, when the subject is a person, the amateur photographer tends to put the whole person in the photograph, and as a result, the case where the horizontal axis H / L is about 0.1 is the most frequent. However, in the case of photographic prints, since a silver salt film is used as a recording medium as a recording medium, an image printed on a photographic printing paper has a high degree of resolution and is clearly visible, which is not a problem.

On the other hand, in a method of reproducing a captured image on a TV screen, for example, TV broadcasting, the following photographic device is used. FIG. 7 shows a normal TV screen. In FIG. 7, L shows the vertical size of the screen, and H shows the size of the face. FIG. 8 shows the proportion H / L of the face of the person image sent from the TV broadcasting station on the TV screen shown in FIG. 7 on the vertical axis and the frequency of occurrence of the proportion H / L on the vertical axis. It is shown. The figure shows that the frequency is highest when H / L is about 0.3. As described above, when the subject is a person in the TV image of the TV broadcasting station, in order to increase the resolution of the captured image and make it easier to see, in order to make it easier to see, the face part occupies about 30% of the TV screen and is broadcast. You can see that

As shown above, when the subject is a human, if you shoot with an electronic still camera as if you were shooting with a camera using a general silver salt film, you can reproduce the shot image on the TV screen especially to capture a small face. In the case of doing so, there is a problem that the resolution is lowered and it is difficult to distinguish the face.

Therefore, there is a demand for an electronic still camera having a function of allowing a photographer to intentionally show a large image of his face.

Recently, a so-called TV photo system in which a magnetic film for an electronic camera is used to record and store an object to be photographed, such as a negative film or a print, is reproduced by a reproducing device as necessary, and is projected on a TV screen to be enjoyed. Is being used. Even in such a system, it is necessary to take a close-up picture because the person is projected on the TV screen and is viewed.

[Purpose of device]

The present invention has been made in view of such circumstances, and an object thereof is to propose an electronic still camera having a function of prompting close-up photography when a subject is located at a long distance in portrait photography.

[Outline of device]

In order to achieve the above-mentioned object, the present invention forms a subject image on a light-receiving surface of a solid-state image sensor through a taking lens, and a video signal representing a subject image photoelectrically converted by the solid-state image sensor is recorded on a recording medium. In the electronic still camera for recording,
Distance measuring means for measuring the distance to the subject, automatic focusing mechanism for automatically focusing the photographing lens based on the output signal of the distance measuring means, and port for selecting a portrait mode for photographing a person When the portrait mode is selected by the rate mode selection switch and the portrait mode selection switch, the ratio of the face length to the vertical length of the screen is estimated by the shooting distance measured by the distance measuring means, Means for generating an alarm signal prompting a close-up of the face image when the ratio becomes a predetermined value or less,
And an alarm means for issuing an alarm according to the alarm signal.

〔Example〕

Hereinafter, preferred embodiments of an electronic still camera according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the appearance and use example of an electronic still camera according to an embodiment of the present invention. In the figure, 10 is a body of an electronic still camera, 12 is a taking lens, 14 is a stroboscopic light emitting unit, 16 is a finder, 17 is an alarm generating unit, and 18 is a magnetic sheet as an image recording medium. Further, the electronic still camera and the subject 20 are arranged with a distance of approximately l, and the distance to the subject is accurately measured by a known autofocus technique, and the image is automatically focused based on the result. At the same time, distance information indicating whether or not the subject is located farther than a predetermined distance is displayed via a warning lamp.
The electronic camera can switch between a portrait mode and a normal mode. Hereinafter, description will be made assuming portrait mode.

Next, an outline of the operation of the electronic still camera will be described with reference to FIG. FIG. 2 is a block diagram showing an outline of an electric circuit of the electronic still camera shown in FIG.
In the figure, reference numeral 23 designates a distance measuring circuit for measuring the distance from the photographing point to the subject, which is an automatic focusing mechanism unit which is synchronized with an output signal (not shown) of the distance measuring circuit 23 integrally formed with the optical system 26. An image of the subject is converted into a photoelectric conversion device (not shown).
It is imaged on 28 charge-coupled device (CCD) surfaces and recorded as a static image of the charge pattern. Further, the scan control circuit 30 scans the charge pattern formed on the charge coupled device, and based on this, the video signal processing circuit 32 converts it into a video signal. Next, if the distance to the subject is within a predetermined value, the recording circuit 38 receives the output signal 36 of the control circuit 24 and further performs signal processing on the video signal to magnetically record it on the magnetic sheet 40. If the distance to the subject is equal to or greater than a predetermined value, the alarm circuit 34 receives the alarm signal 42 output from the control circuit 24 and turns on a warning lamp to alert the photographer.

Here, a method of warning the distance and position of the subject will be described in detail with reference to FIGS. 3 and 4 below.
FIG. 3 shows a control circuit for generating a signal (alarm signal) for operating the alarm circuit shown in FIG. In the figure, the power supply 44 can be pushed to the middle of the shutter release button.
It is connected to a power switch 46 that is turned on, and a current is supplied to the circuit when the shutter release button is pressed at an intermediate position or higher. The E terminal of the light receiving element 48 whose C terminal is connected to the power switch 46 is connected to the capacitor 50 to charge it, and
A normally-closed switch 52, which is turned off when the shutter release button is fully pressed, is connected in parallel to the capacitor to initialize the capacitor 50. The voltage of the capacitor 50 is input to the-terminal of the comparator 54. The capacitor 50 is also a transistor 58 which is turned off by a high level (hereinafter referred to as H level) output from the Q terminal of the flip-flop 56.
And resistor 60 to the power switch 46 to provide another charging path to the capacitor 50 when the transistor 58 is ON. A resistor 62 is connected to the positive terminal of the comparator 54.
When the reference voltage is input by 64 and the voltage at the − terminal is higher than the voltage at the + electron, the comparator 54 outputs the H level to the transistor 66.

The distance measuring circuit 23 outputs a signal depending on the case where the subject is located at a distant position or when the subject is located at a near position. For example, when the subject is located within a predetermined distance, it remains at the L level. However, when it detects that it is farther than the predetermined distance, it outputs the H level and inputs it to the S terminal of the flip-flop 56. Further, the switch 70 is always connected as shown by the solid line, and is connected as shown by the broken line at the time of shutter release, the common terminal is grounded via the capacitor 72 and the resistor 74, and the R terminal of the flip-flop 56 is connected by the capacitor. Connected so that the pulse differentiated by 72 is input.

Turn off the strobe power switch (not shown) by energizing
One terminal of the first solenoid 76 is a power switch 46
The other terminal is grounded through a transistor 78 which is turned on by the H level input of the Q output of the flip-flop 56. Further, when the transistor 78 is turned on, the switch 73 integrated with the first solenoid 76 operates. Further, one terminal of the second solenoid 80, which maintains the open state made by the mechanical operation of the shutter mechanism (not shown) by the bias, is connected to the power switch 46, and the other terminal is at the H level from the comparator 54. Is grounded via a transistor 66 which is turned on by the input of.

In the above circuit, the power switch 46 is turned on by pressing the shutter release button halfway, and the distance measuring circuit 23 operates to measure the subject distance, and at the same time, the reference voltage is applied to the + terminal of the comparator 54. On the other hand, the switch 52 is still closed, and the negative potential of the comparator 54 is supplied with the ground potential. Therefore, at the same time when the switch 46 is turned on, the comparator 54 outputs the H level, the transistor 66 is turned on, the second solenoid 80 is energized, and the shutter mechanism is kept open. During the shutter release operation, the switch 70 momentarily falls to the broken line side to reset the flip-flop 56.

Then, when the shutter release button is completely pressed, the switch 52 is turned on, but since the capacitor 50 is not charged, the voltage at the negative terminal of the comparator 54 is low, and the comparator 54 outputs the H level. The 2-solenoid 80 remains energized to maintain the open state of the shutter mechanism that is mechanically opened by the pressing. In order to charge the capacitor 50, the light receiving element 48 and the transistor 58 are provided, and the charging time of the capacitor 50, that is, the time for maintaining the open state of the shutter mechanism can be adjusted by changing the resistances thereof.

Next, the configuration of the alarm circuit of FIG. 4 will be described. In the figure, a light emitting diode as a lamp is provided in the collector of the transistor 82 which is turned on in response to the alarm signal 42 shown in FIG.
83 (hereinafter referred to as an LED) is connected, and a protection resistor R that limits the current flowing through the LED 83 is connected in series with the LED 83. Further, one end of the protection resistor R is connected to the power supply line.

If the subject is within the prescribed distance, the distance measuring circuit
The output of 23 is at L level (hereinafter referred to as L level),
Flip-flop 56 is not set. Since the flip-flop 56 is in the reset state and the Q terminal of the flip-flop 56 is at the L level, the transistor 58
Is turned on. Therefore, the capacitor 50 is charged through the transistor 58 and the resistor 60, and at the same time the light receiving element is
Charged via 48. The internal resistance of the light receiving element 48 changes according to the amount of received light, and the capacitor 50
The time required to exceed the reference voltage of the + terminal of 54 changes depending on the amount of received light. After a predetermined time determined by the amount of light,
When the voltage of the capacitor 50, that is, the voltage of the-terminal of the comparator 54 exceeds the reference voltage, the output of the comparator 54 becomes L level, the transistor 66 is turned off, the second solenoid is deenergized, and the shutter mechanism is closed. Separately from this, the first solenoid 76 is not energized because the output of the flip-flop 56 is at the L level, and the switch 73 is turned off.
Since the state remains as it is, the alarm signal 42 is not output and the LED 83 of the alarm circuit shown in FIG. 4 is not turned on.

On the other hand, when the distance measuring circuit 23 detects that the object is farther than the predetermined distance and outputs the H level, the flip-flop 56 is set, so that the transistor 58 outputs the H level from the flip-flop 56. OFF by input
Becomes Therefore, the capacitor 50 is charged only by the current flowing through the light receiving element 48 in proportion to the amount of light received, and therefore, the negative terminal of the comparator 54 after a predetermined time longer than when the distance measuring circuit 23 outputs the level. Is higher than the potential at the same + terminal. This makes the flip-flop
56 is set, transistor 78 is flip-flop 56
The first solenoid is turned on by the H level from
76 is energized to stop the flash firing. Separately from this, the first solenoid 76 is energized because the output of the flip-flop 56 is at the H level, and the switch 73 is turned on. As a result, the alarm signal 42 is output from the control circuit,
Transistor 82 of the alarm circuit shown in the figure receives this alarm signal 42 and turns on, and current flows to the collector.
3 turns on.

In the above embodiment, when the distance to the subject is equal to or greater than the predetermined value, the lamp 83 is turned on to give an optical warning, but an acoustic method such as electronic sound, voice synthesis sound, and acoustic buzzer may be used. I do not care. Further, the lamp need not be provided separately as in this embodiment, but may be provided inside the finder.

Furthermore, in an electronic still camera with a built-in electronic viewfinder, a warning may be given to blink the screen regardless of whether it is a cathode ray tube or a liquid crystal display, or a warning may be issued by a lamp or an audio device provided separately from this. Good.

Further, the warning by the lamp may be changed to the blinking operation instead of the lighting.

[Effect of device]

As described above, according to the electronic still camera of the present invention, when the distance to the subject is equal to or larger than the predetermined distance, a warning is issued, so that the photographer can be warned and a large copy can be made.

[Brief description of drawings]

1 is a perspective view showing the appearance of an electronic still camera according to an embodiment of the present invention, FIG. 2 is a block diagram showing a schematic electric circuit of the electronic still camera shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a circuit diagram showing the control circuit shown in FIG. 4, FIG. 4 is a circuit diagram showing an alarm circuit, FIG. 5 is an explanatory diagram showing a photographic print, and FIG.
Explanatory drawing showing the ratio occupied by the face of the subject shown in FIG.
FIG. 8 is an explanatory diagram showing a TV screen, and FIG. 8 is an explanatory diagram showing a proportion of the face of the portrait shown in FIG. 23 ... Distance measuring circuit, 24 ... Control circuit, 26 ... Optical system, 28 ... Photoelectric / electric converter, 30 ... Scan control circuit, 32 ... Video signal processing circuit, 34
... Finder, 36 ... Recording circuit control signal, 38 ... Recording circuit,
40 ... Magnetic sheet, 83 ... Light emitting diode.

Claims (1)

(57) [Scope of utility model registration request] 1. An electronic still camera which forms a subject image on a light-receiving surface of a solid-state image sensor through a photographing lens and records a video signal representing the subject image photoelectrically converted by the solid-state image sensor on a recording medium. Distance measuring means for measuring the distance to the subject, automatic focusing mechanism for automatically focusing the photographing lens based on the output signal of the distance measuring means, and port for selecting a portrait mode for photographing a person When the portrait mode is selected by the rate mode selection switch and the portrait mode selection switch, the ratio of the face length to the vertical length of the screen is estimated by the shooting distance measured by the distance measuring unit, A means for generating an alarm signal prompting a close-up of the face image when the ratio becomes a predetermined value or less, and an alarm for issuing an alarm by the alarm signal. An electronic still camera characterized by comprising a stage, a.