JPH0818842A - Video camera - Google Patents

Abstract

PURPOSE:To provide a video camera in which a defect problem is eliminated in the use of a zoom lens and a continuous zoom magnification is obtained similarly to the case with the use of the zoom lens. CONSTITUTION:An optimum magnification for a multi-focus lens 1 as an image pickup lens is switched discontinuously by selecting a focal distance. The multi- focus lens 1 is made up of a pan focus lens. An image pickup signal from an image pickup element 2 is processed by a camera processing circuit 3 to obtain a video signal SVa. The electronic zoom circuit 4 applies processing for image magnification to the video signal SVa to form a video signal SVb. A microcomputer 5 selects the optical magnification of the multi-focus lens 1 depending on zooming by a zoom lever 7 and controls an electronic zoom magnification in the electronic zoom circuit 4 so as to control the electronic zoom magnification in the electronic zoom circuit 4 thereby interpolating other magnification than the optical magnification switched by the multi-focus lens 1 and changing continuously the zoom magnification similarly to the case with the use of a zoom lens.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera suitable for application to, for example, a camera-integrated video tape recorder.

[0002]

2. Description of the Related Art Conventionally, it is well known that a video tape recorder with a built-in camera has a zoom lens as an imaging lens. According to the device including the zoom lens as described above, continuous zoom operation can be performed, and thus a video having a change can be recorded.

[0003]

However, since the zoom lens is one in which a zoom lens is moved back and forth along the optical axis to continuously change the zoom magnification (optical magnification), the zoom magnification Focus adjustment according to changes is required. Therefore, it is necessary to separately control both the zoom lens and the focus lens, which complicates the structure of the lens system, which requires complicated adjustment for correcting optical variations and is expensive. There is a problem that it is difficult to reduce the size and weight.

Therefore, the present invention provides a video camera which can eliminate the problems caused by using the zoom lens as described above and can obtain a continuous zoom magnification as in the case of using the zoom lens. To do.

[0005]

A video camera according to a first aspect of the present invention processes a pickup signal from a multifocal image pickup lens capable of changing the focal length to change the optical magnification discontinuously. An electronic zoom means for enlarging the image of the obtained video signal, and switching the optical magnification of the multifocal imaging lens according to the zoom operation and interpolating a magnification other than the optical magnification switched by the multifocal imaging lens. In this way, the zoom control means for controlling the electronic zoom magnification in the electronic zoom means to continuously change the zoom magnification is provided.

A video camera according to a second aspect of the present invention is the video camera according to the first aspect of the invention, wherein the optical magnification of the multifocal imaging lens is switched within a vertical blanking period.

A video camera according to a third aspect of the present invention is the video camera according to the first aspect, further comprising memory means for writing the video signal subjected to image enlargement processing by the electronic zoom means, and a memory for switching the optical magnification in the multifocal imaging lens. The video signal for one screen immediately before the means is repeatedly read and output.

[0008]

According to the first aspect of the invention, the electronic zoom in the electronic zoom means is adapted to switch the optical magnification of the multifocal imaging lens according to the zoom operation and to interpolate a magnification other than the optical magnification switched by the multifocal imaging lens. The zoom magnification is continuously changed by controlling the magnification, and it is possible to continuously change the zoom magnification without using the zoom lens as in the case of using the zoom lens. Further, since the multifocal image pickup lens is used as the image pickup lens, the structure of the lens system becomes simpler and the adjustment for correcting the optical variation becomes simpler than the case where the zoom lens is used. In addition, it is possible to reduce the cost and to reduce the size and weight. Since the electronic zoom is used to interpolate magnifications other than the optical magnification that can be switched by the multifocal imaging lens, the electronic zoom magnification does not increase so much and deterioration of resolution due to the electronic zoom can be suppressed. Become.

According to the second aspect of the invention, the switching of the optical magnification in the multifocal imaging lens is performed within the vertical blanking period, and it is possible to avoid the influence of the switching of the optical magnification on the display image.

According to the third aspect of the present invention, when switching the optical magnification in the multifocal imaging lens, the video signal for the immediately preceding one screen is repeatedly read out and output from the memory means, and the optical magnification is switched to the display image. It is possible to avoid the effects from appearing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a multifocal lens as an imaging lens. As is well known, the multifocal lens 1 can switch the optical magnification discontinuously by switching the focal length. In this example, the optical magnification can be switched to × 1, × 3, and × 6. Further, this multifocal lens 1 is composed of a pan focus lens, and even if the optical magnification is switched, focus adjustment (focusing) is unnecessary. Switching of the optical magnification of the multifocal lens 1 is performed by a microcomputer (microcomputer) 5 that constitutes a system controller.
Controlled by.

Reference numeral 2 is an image pickup device composed of a CCD or the like. A subject image is formed on the image pickup surface of the image pickup element 2 by the multifocal lens 1. The image pickup signal output from the image pickup element 2 is supplied to the camera processing circuit 3. In the camera processing circuit 3, γ correction processing, AGC processing, synchronization addition processing and the like are performed to form the video signal SVa.

The video signal SVa formed by the camera processing circuit 3 is supplied to the electronic zoom circuit 4. The electronic zoom circuit 4 performs image enlargement processing according to the electronic zoom magnification. That is, interpolation processing or the like is performed on the video signal SVa as conventionally known according to the electronic zoom magnification, and the video signal SVb subjected to image enlargement processing is formed. The control of the electronic zoom magnification of the electronic zoom circuit 4 is controlled by the microcomputer 5.

The image-enlarged video signal SVb output from the electronic zoom circuit 4 is output to the output terminal 6. Although not shown, in the camera-integrated video tape recorder, the video signal SVb obtained at the output terminal 6 is supplied to the recording signal processing unit (not shown) and processed, and then recorded on the video tape. .

Reference numeral 7 is a zoom lever for the user to perform a zoom operation to the WIDE (wide angle) side or the TELE (telephoto) side. The operation signal of the zoom lever 7 is supplied to the microcomputer 5. The vertical blanking signal VBLK is supplied to the microcomputer 5 as a timing signal for switching the optical magnification of the multifocal lens 1 as described later.

In the above structure, the microcomputer 5 responds to the zoom operation by the zoom lever 7 in response to the multifocal lens 1
The electronic zoom magnification in the electronic zoom circuit 4 is controlled so as to switch the optical magnification of (1) and to interpolate a magnification other than the optical magnification switched by the multifocal lens 1. This allows the zoom operation by the zoom lever 7 to be performed as shown in FIG.
The optical magnification and electronic zoom magnification change as shown in
As in the case of using the zoom lens, the obtained zoom magnification (the product of the optical magnification and the electronic zoom magnification) can be continuously changed.

For example, when the zoom lever 7 is operated to the TELE side when the optical magnification is × 1 and the electronic zoom magnification is × 1 and the obtained zoom magnification is × 1, the electronic zoom is performed by the microcomputer 5. The zoom magnification obtained by controlling the electronic zoom magnification in the circuit 4 to increase is x.
It will rise more than 1 time. In this state, the electronic zoom magnification is × 3, and the obtained zoom magnification is the multifocal lens 1.
When it becomes equal to the next optical magnification of × 3, the microcomputer 5 switches the optical magnification of the multifocal lens 1 to × 3, and at the same time, the microcomputer 5 increases the electronic zoom magnification in the electronic zoom circuit 4 to × 1. Will be returned.

Further, when the zoom lever 7 is further operated to the TELE side in this state, the electronic zoom magnification in the electronic zoom circuit 4 is controlled to increase by the microcomputer 5, so that the obtained zoom magnification is × 3. Will continue to rise. In this state, when the electronic zoom magnification becomes × 2 and the obtained zoom magnification becomes equal to the next optical magnification of the multifocal lens 1, which is × 6, the microcomputer 5 causes the optical magnification of the multifocal lens 1 to be ×. At the same time as switching to 6 ×, the microcomputer 5 simultaneously returns the electronic zoom magnification in the electronic zoom circuit 4 to × 1.

Further, when the zoom lever 7 is further operated to the TELE side in this state, the electronic zoom magnification in the electronic zoom circuit 4 is controlled to be increased by the microcomputer 5, so that the obtained zoom magnification is × 6. Will continue to rise.

Although a detailed description is omitted, when the zoom lever 7 is operated to the WIDE side, the operation reverse to that of the operation to the TELE side described above is performed continuously in the direction in which the obtained zoom magnification decreases. Change.

FIG. 3 is a flowchart of a subroutine showing the zoom control operation in the microcomputer 5.

First, in step ST1, it is determined whether or not the zoom lever 7 is pressed. If it is not pressed, it returns without doing anything. When pressed,
In step ST2, it is determined whether the TELE side is operated. When it is operated to the TELE side, it is determined in step ST3 whether or not the optical magnification of the multifocal lens 1 is × 1.

If the optical magnification is not x1 in step ST3, it is determined in step ST4 whether the optical magnification is x3. When the optical magnification is not × 3, it is × 6, and therefore there is no need to determine the timing for switching the optical magnification, and in step ST5, the electronic zoom magnification of the electronic zoom circuit 4 is incremented by a predetermined unit amount and the process returns. The increment operation is set so as not to be performed after the electronic zoom magnification reaches a predetermined value, for example, × 3.

If the optical magnification is × 3 in step ST4, the electronic zoom magnification is × 2 in step ST6.
It is determined whether or not the magnification is doubled, and accordingly, it is the timing for switching the optical magnification. If the electronic zoom magnification is not × 2, the switching timing has not yet been reached, so step S
At T5, the electronic zoom magnification is incremented by a predetermined unit amount and the process returns. On the other hand, when the electronic zoom magnification is × 2, the obtained zoom magnification is × 6, which is the optical magnification switching timing. Therefore, in step ST7, the optical magnification is switched to × 6, and at the same time, the electronic zoom is switched. Magnify x1 and return.

If the optical magnification is × 1 in step ST3, the electronic zoom magnification is × 3 in step ST8.
It is determined whether or not it is the magnification, and accordingly, it is the timing for switching the optical magnification. If the electronic zoom magnification is not x3, the switching timing has not yet been reached, so the electronic zoom magnification is incremented by a predetermined unit amount in step ST5, and the process returns. On the other hand, when the electronic zoom magnification is × 3, the obtained zoom magnification becomes × 3, which is the optical magnification switching timing, and therefore step ST9.
The optical magnification is switched to x3 and the electronic zoom magnification is simultaneously set to x1, and the process returns.

Next, when the zoom lever 7 is operated to the WIDE side in step ST2, step ST10
Then, it is determined whether the optical magnification of the multifocal lens 1 is × 6.

If the optical magnification is not × 6 in step ST10, it is determined in step ST11 whether the optical magnification is × 3. If the optical magnification is not × 3, ×
Since it is 1 ×, it is not necessary to determine the timing of switching the optical magnification, and in step ST12, the electronic zoom magnification of the electronic zoom circuit 4 is decremented by a predetermined unit amount and the process returns. The decrement operation is set so as not to be performed after the electronic zoom magnification becomes × 1.

In step ST11, the optical magnification is × 3.
If it is double, it is determined in step ST13 whether or not the electronic zoom magnification is × 1, that is, it is the timing for switching the optical magnification. If the electronic zoom magnification is not x1 times, the switching timing has not been reached yet, so the electronic zoom magnification is decremented by a predetermined unit amount in step ST12, and the process returns. On the other hand, when the electronic zoom magnification is × 1, the obtained zoom magnification is × 3, which is the optical magnification switching timing.
At 14 the optical magnification is switched to × 1 and at the same time the electronic zoom magnification is set to × 3 and the process returns.

In step ST10, the optical magnification is × 6.
If it is, it is determined in step ST15 whether or not the electronic zoom magnification is × 1 and, therefore, it is the timing for switching the optical magnification. If the electronic zoom magnification is not x1 times, the switching timing has not been reached yet, so the electronic zoom magnification is incremented by a predetermined unit amount in step ST12, and the process returns. On the other hand, the electronic zoom magnification is ×
When the magnification is 1 ×, the obtained zoom magnification is × 6, which is the optical magnification switching timing. Therefore, in step ST16, the optical magnification is switched to × 3, and at the same time, the electronic zoom magnification is set to × 2. To return.

By the way, depending on the structure of the multifocal lens 1, it is conceivable that the display image is affected by the switching of the optical magnification. In order to avoid this, in the present example, the above-mentioned switching of the optical magnification in the multifocal lens 1 is performed within the vertical blanking period based on the vertical blanking signal VBLK. A memory means for writing the video signal SVb output from the electronic zoom circuit 4 is provided, and when switching the optical magnification of the multifocal lens 1, the video signal for one screen immediately before is repeatedly read from this memory means. It may be possible to avoid the influence on the display image by switching the optical magnification by outputting.

As described above, in this example, the optical magnification of the multifocal lens 1 is switched according to the operation of the zoom lever 7, and the optical magnification (× 1, × 3, ×) that can be switched by the multifocal lens 1 is switched. The electronic zoom magnification of the electronic zoom circuit 4 is controlled so as to interpolate a magnification other than 6 times, and the obtained zoom magnification (the product of the optical magnification and the electronic zoom magnification) changes continuously. Therefore, the zoom magnification can be continuously changed without using the zoom lens as in the case of using the zoom lens. Further, since the multifocal lens 1 is used as the imaging lens, the structure of the lens system is simpler and the adjustment for correcting the optical variation is simpler than the conventional one using the zoom lens. . In addition, it can be constructed at low cost and can be made compact and lightweight. Furthermore, since the electronic zoom circuit 4 is used to interpolate magnifications other than the optical magnification that can be switched by the multifocal lens 1, the electronic zoom magnification does not increase so much and deterioration of resolution due to the electronic zoom can be suppressed. it can.

In the above-mentioned embodiments, the example in which the optical power of the multifocal lens 1 is x1, x3, x6 has been shown, but no matter how many steps the optical power is, No matter how the intervals of the respective magnifications are assigned, the zoom magnification can be continuously changed by the similar configuration. It is also possible to use a monofocal lens instead of the multifocal lens 1 and obtain a continuous zoom magnification only with the electronic zoom circuit 4.

[0033]

According to the first aspect of the present invention, the electronic zoom means is arranged so that the optical magnification of the multifocal imaging lens is switched according to the zoom operation and the magnification other than the optical magnification switched by the multifocal imaging lens is interpolated. The electronic zoom magnification is controlled to continuously change the zoom magnification, and the zoom magnification can be continuously changed without using the zoom lens as in the case of using the zoom lens. Further, since a multifocal image pickup lens is used as the image pickup lens, the structure of the lens system is simpler than that using a zoom lens, and adjustments for correcting optical variations can be performed easily and at low cost. It can be configured and can be made compact and lightweight. Further, since the electronic zoom is used to interpolate magnifications other than the optical magnification that can be switched by the multifocal imaging lens, the electronic zoom magnification does not become so large and deterioration of the resolution due to the electronic zoom can be suppressed to a small extent.

According to the invention of claim 2, the switching of the optical magnification in the multifocal imaging lens is performed within the vertical blanking period, and it is possible to avoid the influence of the switching of the optical magnification on the display image.

According to the third aspect of the present invention, when switching the optical magnification in the multifocal imaging lens, the video signal for one screen immediately before is repeatedly read out and output from the memory means, and the optical magnification is switched to the display image. It is possible to avoid the effect of.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a video camera according to the present invention.

FIG. 2 is a diagram for explaining how to change a zoom magnification.

FIG. 3 is a flowchart showing a zoom control operation of a microcomputer.

[Explanation of symbols]

 1 Multifocal lens 2 Image sensor 3 Camera processing circuit 4 Electronic zoom circuit 5 Microcomputer 6 Output terminal 7 Zoom lever

Claims (3)

[Claims] 1. A multifocal imaging lens capable of switching the focal length to switch the optical magnification discontinuously, and an electronic for enlarging an image of a video signal obtained by processing an imaging signal from an imaging device. The electronic zoom magnification in the electronic zoom means is controlled so as to switch the optical magnification of the multifocal imaging lens according to zoom operation and the zoom operation and to interpolate a magnification other than the optical magnification switched by the multifocal imaging lens. And a zoom control means for continuously changing the zoom magnification. 2. The video camera according to claim 1, wherein the switching of the optical magnification in the multifocal imaging lens is performed within a vertical blanking period. 3. A memory means for writing a video signal subjected to image enlargement processing by the electronic zoom means is provided, and when switching the optical magnification in the multifocal imaging lens, a video signal for one screen immediately before the memory means is repeated. The video camera according to claim 1, which reads out and outputs.