JPH05191704A - Electronic image pickup device - Google Patents

Abstract

PURPOSE:To attain video recording with high picture quality with reduced power consumption at zooming by using an electronic zoom means and an optical zoom means in common. CONSTITUTION:In the recording standby state, an optical zoom system 1 is set to the WIDE position and an image pickup circuit 3 and a control circuit 7 of the electronic zoom system are set so as to be in operation within a focal distance range coped with the optical zoom system 1. Then the state prior to recording, the electronic zoom system is made to OFF and an optical zoom control circuit 6 drives a zoom motor 8 to move the optical zoom system to a position corresponding to the focal distance of the electronic zoom to be set to the recording standby state. Since the optical zoom system is not driven in the recording standby state, power consumption is reduced and video image with high picture quality is obtained by recording the video image with the optical zoom system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic image pickup device, and more particularly to an electronic image pickup device which saves power consumption associated with driving a zoom motor.

[0002]

2. Description of the Related Art For example, when changing the zoom magnification in an electronic image pickup apparatus such as an electronic still camera or a video camera, the focal length of a built-in optical system is changed to change the magnification of an image formed on an image pickup device such as a CCD. This is done by varying optical zoom means. When recording an image using such an electronic imaging device, the focal length is complicatedly changed by the optical zoom means in order to adjust the angle of view to the subject. Therefore, the zoom motor for moving the optical system must be driven for each change, the power consumption for driving the motor becomes significant, the battery consumption also progresses, and in the worst case, the actual shooting recording Sometimes the battery power runs out and recording becomes impossible.

In order to solve this problem, a video memory is built in the electronic image pickup apparatus, and an electronic zoom for enlarging the subject image at a predetermined magnification by subjecting a video signal obtained from the image pickup element to a predetermined signal processing. Devices using means have been proposed. For example, in Japanese Patent Laid-Open No. 3-141327, an optical zoom means and an electronic zoom means are provided, and the optical zoom means is used up to a magnification that the optical zoom means can handle, and the optical zoom means cannot handle. There is disclosed a technique for obtaining a wide range of magnification change by operating an electronic zooming means in a region exceeding a large magnification.

[0004]

As described above, the conventional electronic image pickup device obtains an image with a wide range of magnification by providing the optical zoom means and the electronic zoom means. However, the electronic zoom means further expands the TELE side that can be supported by the optical zoom means.
Although a large magnification can be obtained, there is a problem that the actual image quality deteriorates according to the magnification set in the electronic zooming means.

Therefore, an object of the present invention is to provide an electronic image pickup apparatus capable of obtaining a high-quality image at the time of recording an actual image while minimizing the power consumption due to the driving of the zoom motor.

[0006]

In order to solve the above-mentioned problems, an electronic image pickup apparatus according to the present invention is an optical zoom means for selectively setting an optical zoom magnification by moving an optical element by a driving means. And an electronic zoom means for variably setting an electronic zoom magnification by changing a process of forming a video signal by the image pickup means, and a period excluding a period for recording the video signal generated by the image pickup means. In at least a part of the period, the total zoom magnification is variable within a predetermined range with respect to a change in the direction in which the total zoom magnification increases based on the product of the optical zoom magnification and the electronic zoom magnification. The optical zoom means is caused to selectively set a predetermined one of the optical zoom magnifications corresponding to the section, and the total zoom magnification is changed in the decreasing direction. On the other hand, a predetermined other zoom magnification of the optical zoom magnification is set to the optical zoom means corresponding to a predetermined other variable section that partially overlaps the predetermined one range of the total zoom magnification. During the period in which the first control unit that is selectively set and the video signal generated by the image pickup unit are recorded, the optical zoom magnification selectively set by the first control unit and the total zoom by the corresponding electronic zoom unit are performed. Second control means for newly setting the value of the magnification as the optical zoom magnification and for setting the zoom magnification by the electronic zoom means to a predetermined reference value.

[0007]

According to the present invention, the optical zooming means and the electronic zooming means are provided, and the operation of the optical zooming means is minimized at the stage of preparation for recording such as selection of the composition of an object to be photographed. However, the zoom image obtained by the optical zoom means is mainly recorded at the time of actual recording, so that it is possible to save the power consumption during the period other than the recording and to record the image with high image quality.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an electronic image pickup apparatus according to the present invention. The subject is imaged on the image sensor 2 such as a CCD via the optical system 1. Optical system 1
Is composed of, for example, four groups of optical systems, and a zoom lens system 111 is provided as one of the groups. The zoom lens system 111 is moved by a zoom motor 8 which is rotationally driven by a control signal supplied from the optical zoom control circuit 6, and its position is controlled. Zoom encoder 9
Detects the position of the zoom lens system 111 and sends it to the optical zoom control circuit 6. The image signal obtained by the image pickup device 2 is subjected to a predetermined image pickup process in the image pickup circuit 3 to obtain an EVF.
It is sent to the (electronic viewfinder) 4 and the recording circuit 5. The image pickup circuit 3 also performs an electronic zoom process by the electronic zoom control circuit 7 under the control of the system control circuit 10. This electronic zoom processing includes, for example, drive control processing of the image sensor (CCD) 2 and continuous magnification electronic zoom processing by linear interpolation. The recording circuit 5 is the imaging circuit 3
The video signal from is subjected to processing necessary for recording and sent to the recording system. The system control circuit 10 is provided with five types of switches such as a T switch, a W switch, an RT switch, a ZM1 switch, and a ZM2 switch. The T switch is for TELE operation, the W switch is for WIDE operation, the RT switch is for sending REC TRIG for performing recording start command control, and the ZM1 switch and ZM2 switch are for zoom mode 1 and zoom mode 2 setting. The system control circuit 10 sends a zoom control signal to the optical zoom control circuit 6 and the electronic zoom control circuit 7 in accordance with the operating states of these switches.

FIG. 2 shows the zoom mode switch ZM1.
And operation modes of the optical zoom system and the electronic zoom system corresponding to the setting conditions of ZM2. Mode 1 is an operation mode in which both the zoom mode switches ZM1 and ZM2 are in the OFF state, and the recording standby (REC STANDB
In the Y) state, the optical zoom system is fixed to the predetermined WIDE side, and the electronic zoom system operates to perform the zoom operation. Also,
In the (REC TRIG) state prior to recording, the optical zoom system operates and the electronic zoom system is turned off. Mode 2 is an operation mode in which the zoom mode switch ZM1 is off and the zoom mode switch ZM2 is on.
In the recording standby state and the state prior to recording, the optical zoom system operates, the electronic zoom system operation is turned off, and the same operation as the electronic image pickup apparatus having only the optical zoom system is performed. In mode 3, the zoom mode switch ZM1 is ON, ZM
2 is in the OFF state, and in the recording standby state, the optical zoom system performs a rough operation and the electronic zoom system performs a fine operation. In the state prior to recording, the optical zoom system is operated and the electronic zoom system is turned off. In mode 4, the zoom mode switches ZM1 and ZM2 are in the ON state,
Both the optical zoom system and the electronic zoom system operate both in the recording standby state and in the state prior to recording. In this mode, the image quality is deteriorated because the electron beam system is also operated during recording, but it is effective when high magnification is required.

The above modes will be described in more detail below. In the mode 1, as described above, in the recording standby state, the optical zoom system is fixed to the WIDE side, and the electronic zoom system is set to operate within the focal length range that the optical zoom system can support. Further, in the state prior to recording, the electronic zoom system is turned off, and the optical zoom system is moved and driven to a position corresponding to the focal length of the electronic zoom set in the recording standby state. By doing this, it is not necessary to drive the zoom lens of the optical zoom system in the recording standby state, and it is possible to obtain low power consumption, and for recording, the image obtained by the optical zoom system is recorded without operating the electronic zoom system. High-quality image recording is performed. The operation and processing procedure in mode 1 will be described with reference to FIGS. 3 and 4. In the recording standby state (REC STANDBY), as shown in FIG. 3, first, the optical zoom ratio (magnification) OZ and the electronic zoom ratio EZ are respectively set to 1 (step S1). Next, the zoom ratio of the optical zoom system is set to OZ (step S
2) After setting the zoom ratio of the electronic zoom system to EZ (step S3), the ZT switch and ZW switch are monitored (step S4), and the zoom TELE and WIDE switches are set to TE.
When it is turned on to the LE side, the zoom ratio EZ of the electronic zoom system is set to (EZ + k) to increase the zoom magnification (step S5). Here, k represents the amount of change in the zoom ratio according to the zoom speed at that time. After that, the zoom ratio (“6” in this example) set as the maximum magnification of the optical zoom system is compared with the zoom ratio EZ of the electronic zoom system (step S6). If EZ is less than 6, step S3 is performed.
If EZ is 6 or more, the process returns to step S7, the value is fixed to EZ = 6 (step S7), and the process returns to step S3. In step S4, the WIDE of the zoom switch
If the side is ON, EZ = EZ-k is set and the zoom magnification is reduced (step S8), and EZ is compared with the minimum possible magnification 1 (step S9). If EZ is larger than 1, the process returns to step S3. If EZ is 1 or less, EZ is set to 1 (step S10) and then the process returns to step S3.

When the recording instruction signal REC TRIG is input and recording is started, as shown in FIG. 4, first, the zoom ratio OZ of the optical zoom system is set to EZ × OZ to the zoom ratio set in the recording standby state. Yes (step S1
1 and S12). Next, after setting the zoom ratio of the electronic zoom system to 1 (step S13), preparations for recording other than the zoom operation (for example, driving of AF, AE, AWB, still video spindle motor (SPM), etc.) are performed (step S13). S1
4) The recording operation is performed (step S15). Next, OZ
÷ EZ is set as OZ (step S16), and the operation returns to the recording standby state as shown in FIG.

In mode 2, the electron beam system is turned off and only the optical zoom system is used in both the recording standby state and the state prior to recording. This mode is more disadvantageous in terms of power consumption than Mode 1, but when the subject is moving at a high speed, there is no optical zoom operation after REC TRIG input and there is no time lag, so there is a shutter chance. Do not let go.

In mode 3, in the recording standby state,
The optical zoom system operates only at some points (discrete points) between WIDE and WIDE / TELE, and the electronic zoom system operates within a range of focal lengths compatible with the optical zoom system. In addition, in a state prior to recording, the electronic zoom system is turned off and the optical zoom system is operated so as to perform zooming to the total zoom magnification of the electronic zoom system and the optical zoom system set during recording standby. FIG. 5 shows an example of the correspondence relationship between the optical zoom system magnification and the electronic zoom system magnification with respect to the total zoom magnification. Figure 5 shows the total zoom ratio.
1 from WIDE to TELE as shown in (A)
It changes from double to eight times. This change is from WIDE to TE
The change in the LE side direction is indicated by WT, and the change from TELE to the WIDE side direction is indicated by TW. The change in magnification of the optical zoom system is set to be different in the WT direction and the TW direction as shown in FIG. That is, in the WT direction, the magnification of the optical zoom system is set to 1 until the total magnification becomes 4 times.
When it doubles, it is set to double. On the other hand, in the TW direction, it remains at 2 times until the total magnification becomes two times, and is set to one when the total magnification becomes two times. This is for the following reason. Ie 1 to 2 times or 2 to 1
If the zoom direction is switched immediately after switching to double, the optical zoom system frequently moves between the zoom magnifications of 1 × and 2 ×, and power consumption increases. Therefore, the figure (B)
As shown in, the switching timing is provided with hysteresis to prevent such frequent switching, and a power saving effect is obtained. Also, this hysteresis is set biased toward the WIDE side, but this setting is based on which magnification the electronic zoom system can maintain good image quality and which zoom magnification is often used. Selected and set. That is, in this example, the maximum magnification of the electronic zoom system is set to 4 times (× 4), and it is stipulated that the electronic zoom system is often used on the TELE side.

The zoom magnification of the electronic zoom system changes as shown in FIG. 5 (C) in order to obtain the total magnification shown in FIG. 5 (A) corresponding to the change in the optical zoom system magnification. That is, WT
In the direction, the total magnification changes similarly from 1 to 4 times,
When the total magnification reaches 4 times, the magnification decreases to 2 times, and thereafter changes as shown in FIG. On the other hand, in the TW direction, as shown in the figure, the magnification becomes 2 times when the total magnification reaches 2. Although the optical zoom system is fixed at two places in this example, it may be fixed at three or more places.

The operation and processing procedure in the above mode are shown in FIG. In the recording standby state, first, both OZ and EZ are set to 1 (step S20), and the optical zoom system is set to O.
After setting to Z (step S21) and the electronic zoom system to EZ (step S22), the zoom switch (Z
It waits for operation control of (T, ZW) (step S23). When the TELE side of the zoom key is turned on, (EZ + k) is set to E
Set to Z to increase the magnification (step S24), and
The maximum magnification 4 of the electronic zoom system shown in (C) is compared with EZ (step S25). If EZ is less than 4, the process returns to step S22, and if EZ is 4 or more, EZ
Is determined to be either # 1 or # 2 in FIG. 5C by checking OZ (step S26). When OZ is 2 in step S26, EZ is # 1 in FIG. 5C, so EZ is set to 4 (step S27), the process returns to step S22, and when OZ is 1, EZ is set. Is # 2 in FIG. 5C, so EZ
After setting both OZ and OZ to 2 (step S2
8) and returns to the process of step S22.

On the other hand, when it is determined in step S23 that the zoom switch is turned on to the WIDE side, EZ is set to (EZ-k) to reduce the magnification (step S29), and EZ is set to 1. Compare (step S3)
0). If it is determined that EZ is greater than 1, the process proceeds to step S22. When it is determined that EZ is 1 or less, OZ is checked to determine whether EZ is # 3 or # 4 in FIG. 5C (step S31). When OZ is 1, since EZ is # 4, after setting EZ = 1 (step S3)
2), the process proceeds to step S22. Further, when OZ is 2, EZ is # 3 in FIG.
After setting EZ to 2 and OZ to 1 (step S33),
The process of step S21 is reached.

In the mode 3, the operation of the optical zoom system in the recording standby state is suppressed, so that the power consumption can be reduced. In mode 1, if the total magnification is 8 times, the electronic zoom system operates, so that deterioration of the recorded image quality cannot be avoided, but in mode 3, the deterioration of image quality is small. Therefore, it is preferable to use switching such that mode 1 is used at low magnification and mode 3 is used at high magnification.

[0018]

As described above, the electronic image pickup apparatus according to the present invention is provided with the optical zooming means and the electronic zooming means, and the optical zooming means of the optical zooming means is provided at the stage of preparation for recording such as selection of the composition of the object to be photographed. Since the operation is kept to a minimum and the electronic zoom means is used, the zoom image mainly obtained by the optical zoom means is recorded during actual recording.
It is possible to save power consumption during periods other than recording and to perform high-quality recording.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electronic imaging device according to the present invention.

FIG. 2 is a diagram showing a zoom operation in modes 1 to 4 in the embodiment of FIG.

FIG. 3 is a flowchart showing an operation processing means in a recording standby state of mode 1 in the embodiment of FIG.

FIG. 4 is a flowchart showing an operation processing unit in a state prior to recording in mode 1 in the embodiment of FIG.

5 is a diagram showing the relationship between changes in the optical zoom system magnification and the electronic zoom system magnification with respect to the total zoom magnification in mode 3 in the embodiment of FIG.

FIG. 6 is a flowchart showing an operation processing procedure in a recording standby state of mode 3 in the embodiment of FIG.

[Explanation of symbols]

1 Optical system 2 Image sensor 3 Imaging circuit 4 EV
F 5 Recording circuit 6 Optical zoom control circuit 7 Electronic zoom control circuit 8 Zoom motor 9 Zoom encoder 10 System control circuit 11 Switch 111 Zoom lens system

Claims (3)

[Claims] 1. An optical zoom means for selectively setting an optical zoom magnification by moving an optical element by a driving means, and an electronic zoom magnification by changing a process of forming an image signal by an image pickup means. Of the optical zoom magnification and the electronic zoom magnification in at least a part of the period excluding the period in which the video signal generated by the image pickup unit is recorded. In response to a change in the direction in which the total zoom magnification based on the product increases, the optical zoom means is provided with a predetermined one of the optical zoom magnifications corresponding to a variable section in the predetermined one range of the total zoom magnification. Of the zoom ratio is selected and set, and with respect to the change in the decreasing direction of the total zoom ratio, the predetermined zoom range partially overlaps the predetermined range of the total zoom ratio. The first control means for selectively setting a predetermined other zoom magnification of the optical zoom magnifications to the optical zoom means corresponding to the variable section of, and a period during which the video signal generated by the image pickup means is recorded. Then, the optical zoom magnification selected and set by the first control means and the value of the total zoom magnification by the corresponding electronic zoom means are newly set as the optical zoom magnification, and the zoom magnification by the electronic zoom means is set to a predetermined value. An electronic image pickup device comprising: a second control unit for setting a reference value. 2. An optical zooming means for selectively setting an optical zooming magnification by moving an optical element by a driving means, and an electronic zooming magnification by changing a process of forming a video signal by an image pickup means. Of the optical zoom magnification to the optical zoom means during at least a part of the period excluding the period for performing the recording of the video signal generated by the image pickup means. Of the first control means for setting / maintaining a predetermined one of the zoom magnifications, and the optical zoom magnification selected and set by the first control means in the period for recording the video signal generated by the image pickup means. The value of the total zoom magnification based on the product of the corresponding electronic zoom means is newly set as the optical zoom magnification, and the zoom magnification by the electronic zoom means is set. Electronic imaging apparatus characterized by comprising by a second control means for setting a reference value of the constant. 3. An optical zoom means for selectively setting an optical zoom magnification by moving an optical element by a driving means, and an electronic zoom magnification by changing a process of forming a video signal by an imaging means. An electronic zooming means for variably setting, and an operation mode selecting means for selectively operating one or both of the optical zooming means and the electronic zooming means according to an operator's option are provided. An electronic image pickup device comprising: