JPH0342751B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention relates to an electronic camera that is equipped with an electronic monitor and has means for changing the driving method of an image sensor in monitor mode. (Background Art) Electronic cameras are promising cameras that can replace silver-halide cameras, but their fundamental problem is firstly that of power consumption.
In other words, when shooting still images intermittently,
Power consumption is not a big problem, but especially for cameras that are connected or equipped with electronic monitors,
The problem of power consumption is extremely important because continuous monitoring or playback is not possible unless the imaging system or reproduction system is continuously driven. Second, there are performance problems such as the resolution of electronic monitors. If the resolution of the electronic monitor is low, false resolution etc. will occur if the same signal processing method is used during monitoring as during recording or reproducing. Furthermore, if the monitor does not have the capability commensurate with the imaging or recording capability, for example, the imaging signal or recording signal is a color signal but the monitor is a monochrome one,
Alternatively, if the reproduction band of the monitor is not as wide as the imaging or recording band, the circuit configuration should be appropriate to the characteristics of the monitor, which is important from the standpoint of reducing power consumption and improving image quality. The third problem is the relationship between the resolution of the monitor and the drive method of the image sensor.If the method drives the image sensor in the same mode during monitoring as during recording or playback, high performance is required of the monitor device. However, if the resolution in the vertical direction is made to match that of the image sensor, the cost will increase. By the way, in conventional electronic cameras, no particular consideration was given to these problems. (Purpose) This invention aims to solve the third problem among the above-mentioned problems, and makes it possible to provide a sufficient monitoring function even when using an electronic monitor in which the number of scanning lines is smaller than the number of vertical pixels of an image sensor. The purpose of the present invention is to provide an electronic camera equipped with the means to do so. (Explanation based on Examples) Hereinafter, the means taken in this invention to achieve the above object will be exemplified and explained with reference to the illustrated embodiments. The following description will be made in order of the overall configuration of an embodiment of the electronic camera of the present invention, the drive method of the image sensor in the monitor mode, and the power supply method and signal processing circuit applied to the above embodiment. (Overall configuration of an embodiment of the electronic camera of this invention)
(Fig. 1) Fig. 1 shows the overall configuration of an embodiment of the electronic camera of the present invention, in which 1 is a subject whose optical image is captured through an imaging optical system 2 such as a lens and a shutter/aperture mechanism 3. The light is received on the surface of the sensor 4. The image sensor 4 can be composed of a two-dimensional or one-dimensional solid-state image sensor such as a CCD or an image pickup tube.
Here, it is assumed that it is a two-dimensional CCD. Reference numeral 5 denotes an automatic focus adjustment (AF)/zoom drive control device, which controls the focal position, focal length, etc. of the imaging optical system 2. 6 is a shutter/aperture drive control device for automatic exposure control (AE), and drives and controls the shutter/aperture mechanism 3. The configurations and functions of these individual elements or devices are well known, so detailed explanations thereof will be omitted. Reference numerals 7A and 7B are drive control circuits for the image sensor 4, which control the impedance, pulse level, rise time and fall time, and the like. Of these, 7A is a drive control circuit for the monitor mode, which will be described later, and 7B is a drive control circuit for the imaging mode, which will be described later.By switching the selector S1, the clock pulses generated by the clock generator 8 are controlled according to each mode. supplied to either one. Although the drive control circuits 7A and 7B are illustrated as separate blocks to make the explanation easier to understand, they may have some of their constituent elements in common, or their circuit constants may be variably controlled mechanically or electronically. This allows all of the constituent elements to be made common, and this point will be explained later in the imaging signal processing circuit 9.
A, 9B and reproduction signal processing circuits 21A, 21B
The same applies to Note that the above-mentioned imaging mode refers to a recording mode described later, an external recording mode, an external monitor mode when an external monitor with high resolution is used, or another mode in which the imaging sensor is driven for the purpose of imaging. The output of the image sensor 4 is sent to an image signal processing circuit 9
It is input to A and 9B. Of these, the processing circuits 9A and 9B are configured to be suitable for processing the output of the image sensor 4 in the monitor mode and recording mode, respectively. The output of the processing circuit 9A is connected to the terminal a of the selector S3, and the output of the processing circuit 9B is input to the recording signal processing circuit 10 and connected to the b terminal of the selector S2.
The recording signal processing circuit 10 converts the output of the imaging signal processing circuit 9B into a signal suitable for recording, and the output is recorded on a magnetic disk 18, which is a recording medium, by a recording head 16 via a recording amplifier 14. Although FIG. 1 shows a magnetic disk, the recording medium in the present invention may be a magnetic tape, or a recording medium using a recording method such as optical recording, optical/magnetic recording, or magnetic bubble recording. The recording head 16 also serves as a reproducing head 17, which will be described later.
It may also be used for both. The magnetic disk 18 is driven and controlled by a motor servo device 19. Signals recorded or previously recorded on the magnetic disk 18 are read out by the reproduction head 17, passed through the reproduction amplifier 15, and inputted to the reproduction signal processing circuit 21A or 21B according to the setting of the selector S4. The processing circuits 21A and 21B are configured to be suitable for supplying reproduction signals to the monitor 24 and an external monitor (not shown), respectively, and their respective outputs are connected to the b terminal of the selector S3 and the selector SS.
Connected to the a terminal of 2. The monitor 24 is configured by, for example, a liquid crystal display (LCD), an electrochrominance display (ECD), or a cathode ray display tube, and is driven and controlled by a monitor drive device 25. 26 is an external video output terminal connected to the common terminal of the selector S2, and the power supply source 27 is
Power is supplied to each of the above-mentioned circuits or devices via the connection lines L1 to L14. (Driving method of the image sensor in the monitor mode according to the embodiment of the present invention) (Figs. 1 to 3) The present invention relates to a case where the number of scanning lines of the monitor built in an electronic camera is smaller than the number of vertical pixels of the image sensor. In the embodiment shown in FIG. 1, the image sensor is driven using fewer scanning lines than in the image pickup mode in order to match the monitor. First, the electronic camera shown in FIG.
The monitor mode, recording mode, monitor playback mode, external monitor mode, external recording mode, and external playback mode are selected by the following settings of 1 to S4, respectively. (1) In monitor mode, S1 is connected to the a terminal, and S3 is connected to the a terminal. (2) In recording mode, S1 is connected to the b terminal and S3 is connected to the b terminal.
Connected to the terminal. (3) In monitor playback mode, S4 is connected to terminal a,
3 is connected to the b terminal. (4) In external monitor mode and external recording mode,
S2 is connected to the b terminal. (5) In external playback mode, S4 is connected to the b terminal, S2
is connected to the a terminal. In addition, in external mode, external video output terminal 2
Each signal is supplied to an external device via 6. In the above, the selectors S1 to S4 that act as mode changeover switches can be configured to be linked to the release or configured as a dial switch, and in the recording mode, the selector S3 can be connected to the a terminal as necessary. Good too. In addition, various modes are possible for the circuit switching in FIG. It is possible to cut off the power supply from the power supply source 27 or reduce the power supply to unnecessary parts (circuits or devices). Here, the scanning and signal readout operations of the image sensor 4 when the drive control circuit 7A or 7B is switched will be described in detail. Now, the electronic monitor 24 built into the electronic camera has n vertical display numbers and m horizontal display numbers, as shown in FIG. 2, and the image sensor 4 has, as shown in FIG.
Assume that it has l vertical pixels and k columns of vertical registers 29. Here, an interline CCD is used in a row as the image sensor 4 (the same applies to other solid-state optical sensors or image pickup tubes), and in general, in image sensors, due to the necessity of interlaced scanning, the sensor drive is also as shown in Fig. 3. After reading out the pixels marked with ○ in one field, the pixels marked with × are read out in one field, so l/2 lines are output in each field, and l lines are output in 1 frame of 2 fields. Become. Or recently, in order to reduce "afterimages", in a certain field, the signal charges of the pixels marked with ○ and the pixels marked with x, which are arranged vertically in the same figure, are added in the vertical shift register 29 by l/2.
A method has also been proposed in which interlace signal output is obtained by outputting as a book, and in the next field, adding the signal charges of two pixels arranged above and below, shifted by one pixel, and outputting as 1/2 lines. However, in either method, if the number n of vertical displays on the electronic monitor 24 that should display the output of the sensor 4 is less than l (for example, but not limited to, l = 490, n = 245). In this case, the number of scanning lines of the image sensor 4 may be changed since the resolution of the monitor is poor. In this invention, the image sensor 4 is driven with fewer scanning lines in the monitor mode than in the imaging mode. Next, the first possible means for achieving this is non-interlaced driving. This is to output only from the pixels marked with ○ or only the pixels marked with x in FIG. According to this drive method, the effective storage time in the sensor is approximately halved, resulting in a decrease in effective sensitivity, but the flickering (vertical slight movement) of the image on the monitor disappears. It goes without saying that even if non-interlace driving is performed in the monitor mode using the built-in monitor 24, the image sensor 4 will be interlaced as usual in the recording mode or in the external monitor mode using a monitor with high vertical resolution. . The second means is the vertical register 29 as described above.
This is non-interlaced driving in which signal charges are added within each field, but the pixel pairs to be added are not changed for each field. This eliminates a decrease in sensitivity and flickering of the image. Further, as another means of adding signal charges, it is also possible to add vertical charges by 2, 3, etc. when moving the signal charges to the horizontal register 30 in FIG. 3. Further, by reducing the reset pulse drive frequency of the output amplifier of the image sensor 4, signal charges can be added at the output stage, and an increase in sensitivity can be expected. Furthermore, in a device having a plurality of horizontal shift registers, by changing the driving method, it is possible to integrate the addition into one horizontal shift register and increase the sensitivity. In this invention, when driving the image sensor in the monitor mode with fewer scanning lines than in the imaging mode, if a method of adding signal charges is adopted as in the embodiment described as the second means, the decrease in resolution can be compensated for. This can be effectively used to increase sensor sensitivity, and the effect of improving monitor (finder) performance can be realized. Of course,
In this case, it goes without saying that the control constants of the shutter/diaphragm drive control device (6 in FIG. 1) for automatic exposure control are made different from those during imaging in response to the increase in sensor sensitivity. (Power supply system and signal processing circuit applied to embodiments of this invention) (Fig. 1) In carrying out this invention, unnecessary parts of the electronic camera shown in Fig. 1 will be changed for each mode. By cutting off the power supply to the electronic camera or reducing the power supply as described below, it is possible to reduce the power consumption, which is an important issue mentioned above, in electronic cameras. In the following description, connection lines L1 to L14 indicate the parts to which power is supplied for each mode, and power supply is cut off or the power supply is reduced to other parts. (1) Monitor mode: L1 to L4, L7, L14 (2) Record mode: L1 to L3, L5, L6, L8
~L10 (3) Monitor playback mode: L10, L11, L1
3, L14 (4) External monitor mode and external recording mode: L1
~L3, L5, L6 (5) External playback mode: L10~L12 Note that in the recording mode, if necessary, power may be supplied via L13 and L14 in addition to the above to operate the monitor 24. In addition, in order to cut off the power supply to unnecessary parts or reduce the power supply for each mode as described above, in conjunction with the switching of the selectors S1 to S4, etc., the above (1) to (5) )
The rated voltage or current is supplied only to the connection wires listed in the following, and the power supply via other connection wires is cut off or the supplied power is reduced, and the selectors S1 to
It is possible to configure the power supply to be automatically controlled in accordance with the operation of S4. As a modification of the above power supply system, a microprocessor is provided in place of the power supply source at the portion 27 in FIG.
1 to L14 are signal lines between the microprocessor and each part of the device, power is supplied to each part of the device through separate connection lines, and the power supply is cut off to each part of the device under the control of the microprocessor. Alternatively, the supplied power may be reduced. Furthermore, in carrying out the present invention, in addition to the above-mentioned means, from the viewpoint of reducing power consumption and improving image quality, a drive control circuit, an imaging signal processing circuit, a reproduction circuit, It is possible to change the circuit configuration of the signal processing circuit, etc., or change the circuit constants. For example, in the monitor mode, the drive control circuit 7A supplies drive pulses suitable for the mode, and the imaging signal processing circuit 9A is configured to be suitable for processing the output of the image sensor 4 in the same mode, or For circuits that have a common circuit configuration, the circuit constants are changed to suit the same mode. Furthermore, in an imaging mode such as a recording mode, the drive control circuit 7B and the imaging signal processing circuit 9B
Alternatively, for those circuits that have a common circuit configuration, the circuit constants are changed to suit the imaging mode. Furthermore, in the monitor playback mode, the playback signal processing circuit 2
1A, or, if the reproduced signal processing circuits have a common circuit configuration, change the circuit constants to suit the monitor reproduction mode. The circuit constants in each of the above modes can be automatically changed and controlled by mechanical or electronic means in conjunction with the selection of each mode, and the drive control circuit, imaging signal processing Even if a part of the circuit configuration, such as a circuit or a reproduction signal processing circuit, is common and the rest is provided separately according to each mode, it is possible to switch the remaining circuit in the same way as described above. . (Effects) As described above, according to the present invention, in the monitor mode, the image sensor adds and outputs pixel signals formed in a predetermined pixel among a plurality of pixels provided on the imaging surface of the image sensor. Therefore, even if an electronic monitor having a number of scanning lines smaller than the number of vertical pixels of the image sensor is used, a sufficient monitoring function can be provided.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the electronic camera of the present invention, Fig. 2 is an explanatory diagram of the pixel configuration of the electronic monitor in the electronic camera of Fig. 1, and Fig. 3 is an explanatory diagram of the driving mode of the image sensor. be. Explanation of the symbols, 1... Subject, 2... Imaging optical system, 3... Shutter/aperture mechanism, 4... CCD which is an image sensor, 5... Automatic focus adjustment/zoom drive control device, 6... Shutter/ Aperture control device, 7
A, 7B... Image sensor drive control circuit, 8... Clock generator, 9A, 9B... Imaging signal processing circuit, 18... Magnetic disk as recording medium, 19
...Motor servo device, 21A, 21B...Reproduction signal processing circuit, 24...Electronic monitor, 25...Monitor drive device, 26...External video output terminal, 2
7...Power supply source, S1 to S4...Selector.

Claims (1)

[Scope of Claims] 1. A plurality of pixels are provided on an imaging surface on which a subject image is formed, and a plurality of pixels are formed in each of the plurality of pixels on the imaging surface according to the subject image formed on the imaging surface. A first image signal is generated by outputting a pixel signal, and a second image signal is generated by adding and outputting pixel signals formed at a predetermined pixel among the plurality of pixels.
an image sensor capable of generating an image signal and capable of generating either the first image signal or the second image signal; and an image sensor outputting the image signal output from the image sensor as an image corresponding to the image signal. a display means for performing display processing for displaying and displaying; a signal processing means for performing processing different from display processing in the display means on the image signal output from the image sensor; When processing the image signal output from the image sensor, a first control mode in which the image sensor generates the first image signal; and a first control mode in which the display means corresponds to the image signal output from the image sensor. An electronic camera comprising: an image sensor control means having a second control mode in which the image sensor generates the second image signal when displaying an image.