JPH04403A - Video camera - Google Patents

Abstract

PURPOSE:To detect the position of a zoom lens with a small number of switches and to prevent the system from malfunctioning by driving the zoom lens temporarily to the telephoto side when the power source is turned on and controlling the setting of a mode with the lens position detection signal. CONSTITUTION:When a detection signal for a macrophotography end point area is obtained from the zoom lens position detection part 15 composed of three units of microswitches SW1 - SW3 at the time of the power-on operation, the zoom lens is driven temporarily to the telephoto side. When a case wherein the lens position is in a normal area is detected from the position detection signal at the time of the deviation of the zoom lens position from the macrophotography end point area at the time of the start of operation as a result of said driving, the driving is stopped and the mode is controlled into a normal mode. Further, when a case wherein the lens position is in a macrophotographic area is detected, the lens is put back to the position at the time of the power-on operation to control the camera into a macrophotographic mode, so the lens position can be detected with a small number of switches.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera having an autofocus function in a normal range from telephoto to a wide angle as well as an autofocus function in a macro range.

[Summary of the Invention] The video camera of the present invention is a video camera in which the position detection signal of the zoom lens driven by autofocus in the macro area is set to be the same at both end positions of the macro area. In order to detect which macro end point the zoom lens is located at, the zoom lens is driven in the telephoto direction and a position detection signal is obtained when it exits the macro end point area. This is to prevent system malfunctions by checking the

Furthermore, in the above video camera, when starting autofocus in the macro area and when the zoom lens enters the macro area from the normal area, only the first macro end point area detection signal is blocked. This prevents the system from malfunctioning.

[Prior Art] Conventionally, in a video camera having an autofocus function, autofocus is achieved by automatically driving a focus lens in a normal range (from the most telephoto position to the widest angle position).

As a focus lens drive control method, for example, by taking advantage of the fact that the frequency components of the video signal excluding the DC component are maximum at the in-focus position, the evaluation value data is calculated by integrating the frequency components of the video signal excluding the DC component. There is a known method (so-called mountain climbing control) in which the lens position is controlled to the position where this evaluation value data is maximum (for example, Patent Application No. 1983-
No. 146628).

By the way, when performing autofocus control, it is necessary to detect the position of the focus lens, and in order to perform related control with the zoom lens, it is also necessary to detect the position of the zoom lens.

As for the conventional position detection method, for a focus lens, a reflective film part is provided on the lens cylindrical part, and a light emitting and light receiving diode is provided as a detection means, and the lens position is detected by obtaining the light reflected by this reflective film part. It has been known.

In particular, Japanese Patent Application No. 63-51293 has been proposed as an invention for effectively detecting the position of the end point of a lens. Furthermore, with respect to zoom lenses, this has been done simply by using a resistor switch or the like.

[Problems to be Solved by the Invention] By the way, if autofocus control is to be performed not only in the normal area but also in the macro area (from the widest angle position to the close-up position in the normal area), it is necessary to Therefore, the lens position is driven by hill-climbing control similar to that of a focus lens. Naturally, more precise position detection of the zoom lens is required. For example, as shown in FIG.
In addition to the detection of the four regions (W, widest angle W), it is essential to detect at least the macro region portion MC and two macro end point regions MC, MC, which are the end points on both sides of the macro region portion MC. However, for example, the maximum telephoto region T
If you want to detect seven areas from MCb to macro end point area MCb, it would require a large detection mechanism to provide multiple switch means that are controlled on/off in response to the zoom lens position within each area. The problem is that it becomes undesirable.

[Means for Solving the Problems] The present invention provides two macro endpoint regions MC, .
While detecting MCb with the same detection signal,
The zoom lens position is MC.

In cases where there is a possibility that it may not be possible to detect which macro end point region of MC2 the zoom lens is in, a means for determining which position the zoom lens is in is provided to prevent system malfunction. It is intended to prevent this.

That is, in a video camera, for example, there is a drive means that drives the zoom lens toward the telephoto side when a detection signal of the macro end point region is obtained when the power is turned on, and a drive means that causes the zoom lens to escape from the macro end point region when the power is turned on by this driving operation. If the position detection signal obtained when the video camera is in the normal region indicates that it is in the normal region, the driving operation is stopped and the video camera is controlled to the normal mode, and
If the position detection signal indicates a macro region, a control means returns the zoom lens driven to the telephoto side by the drive means to the zoom lens position when the power is turned on, and controls the video camera to a macro mode. The purpose is to provide the following:

Furthermore, in the video camera, there is provided a driving means for driving the zoom lens toward the macro side when autofocusing in the macro area is started, and a detection signal for driving the zoom lens when it is detected that the zoom lens has entered the macro end point area. is related to the first macro end point detection after the drive to the macro side is started, and the determining means determines that it is the first macro end point detection. In this case, the zoom lens is provided with a blocking means for blocking the macro end point detection information until the zoom lens passes through the macro end point region.

[Operation] Even if the detection signals of both macro endpoint regions are the same, they can usually be distinguished by the moving direction data of the zoom lens. In other words, if a macro end/point detection signal is obtained during zoom operation (while moving in the macro direction) when the subject is in front of the lens, it means that the zoom lens is located in the macro end point area MC. If the macro end point detection signal is obtained while the zoom lens is being driven in the telephoto direction, the zoom lens is located in the macro end point region MC.

Therefore, normally there is no problem even if the detection signals of both macro endpoint areas are the same, but if the macro endpoint area is detected as the zoom lens position detection signal when the power is turned on, the MC
, MC, it is impossible to detect which position it is in. Also, if the zoom lens enters the macro end point area MC from the normal area at the start of macro mode, the zoom lens is moving in the macro direction. , on the system, the macro end point area MC, is the macro end point area MCI
, it is misunderstood.

Therefore, there is no problem if the position detection error prevention operation is performed by the above-mentioned means only in these cases.

[Embodiment] FIG. 1 is a block diagram of an autofocus control circuit system showing an embodiment of a video camera of the present invention.

1 shows a lens system in which a focus lens and a zoom lens are rotated in the directions of arrows A and B by drive motors 2a and 2b, respectively, and moved in the directions of arrows C and D to control the focal position. The focus lens in the area and the zoom lens in the macro area perform hill climbing control using the contrast detection method (frequency separation method), which will be explained below.
Normal autofocus operation and macro autofocus operation are possible. In this case, the focus lens and zoom lens are focused at a long distance when driven in six directions (= when moved in the C direction), and when driven in the B direction (= when moved in the D force direction). ) is assumed to be focused at close range.

Reference numeral 3 denotes a CCD image sensor, which captures a subject image through the lens system 1 and outputs the image signal to the signal processing circuit 4.

The signal processing circuit 4 forms a luminance signal and a chroma signal from the output signal of the CCD image sensor 3, and is composed of a process circuit, a color encoder, and the like.

5a and 5b are bandpass filters to which the luminance signal taken out from the signal processing circuit 4 is supplied. The bandpass filter 5a has a center frequency of, for example, 1floOKHz, and the bandpass filter 5b has a center frequency of, for example, 5.
00 KHz. These band pass filters 5a, 5
b, a predetermined frequency component in the luminance signal supplied from the signal processing circuit 4 is extracted. The extracted frequency components are then supplied to detection circuits 6a and 6b via amplifiers, and the level of the predetermined frequency components is detected.

7 is a switch circuit, and bandpass filters 5a, 5
The detection output of the frequency component extracted by b is selected to be used as autofocus control data under the control of an autofocus control system controller (hereinafter referred to as controller) IO. For example, when the subject has a strong contrast, the output of the band-pass filter 5a is selected, and when the subject has a weak contrast, the output of the band-pass filter 5b is selected.

The detection output selected by the switch circuit 7, that is, the signal at the level of a predetermined frequency component in the luminance signal, is digitized by the A/D converter 8, and the digital output is supplied to the integration circuit 9. The controller 1 is installed in the integration circuit 9.
An integration area control signal is supplied from A/D converter 8, and level data of a predetermined frequency component in the luminance signal input from the A/D converter 8 is integrated for a period specified by the integration area control signal. As an actual integration operation, for example, a method of integrating the maximum value in one horizontal period for one field can be considered. This integration result data is supplied to the controller IO as evaluation value data Dt.

The controller 10 is configured to perform hill-climbing control using the supplied evaluation value data Dt to achieve autofocus operation. That is,
When the focus lens or zoom lens is driven and the distribution and intensity of the frequency spectrum components are measured in the process of going from a completely out-of-focus state to an in-focus state and then back to an out-of-focus state, it is found that in an out-of-focus state, the spectral components is located on the low frequency side and its size is small, and as it comes into focus, the spectral components shift to the high frequency side and its size increases. From this, autofocus control becomes possible if the lens is driven so that the data obtained by integrating the high-frequency components extracted from the video signal is maximized. Therefore, in the normal area, the focus lens
In addition, in the macro area, the zoom lens is moved back and forth in the lens movement range (N4-4■) as shown in Fig. 2, while searching for the point FP where the evaluation value data Dt is maximum (mountain climbing control). As a result, autofocus is executed in both areas.

11a is a focus lens motor drive circuit, and 11b is a zoom lens motor drive circuit, each of which drives the drive motors 2a and 2b in accordance with drive direction control signals (SF, SR) from the controller 10. Further, a drive speed control signal Ss is supplied via the D/A converter 12, and the lens drive speed is set based on the drive speed control signal SS.

Note that the driving direction control signals S, , S, and the driving speed side m
(The i-ss is generated by the above-mentioned hill-climbing control during autofocus operation. The lens is driven toward the telephoto side by the drive direction control signal SF, and driven toward the macro side by the drive direction control signal Sa. be done.

13) is an orcus lens position detection unit, which forms a reflective film in a predetermined range of a cylindrical portion of the focus lens, irradiates this cylindrical portion with detection light from a light emitting diode, and
The focus lens position is detected depending on whether the irradiated position is a reflective film forming part, that is, whether the rotational position of the cylindrical part in the A direction or the B direction is a position where reflected light can be obtained. The detection signal is sent to the controller 1 via the A/D converter 14.
It is input to 0. Note that this focus lens position detection section 13 has no direct relationship to the present invention, and therefore a detailed description of the position detection method will be omitted.

15 is a zoom lens position detection section, which is composed of three units of microswitches SW1 to SW3. For example, each micro switch S W r is attached to the cylindrical part of the zoom lens.
A groove is formed in a predetermined portion corresponding to SW3, and the slider of each microswitch SW1 to SW3 is turned on/off in accordance with the groove, thereby making it possible to detect the zoom lens position. For example, the microswitches SW1 to SW3 are controlled on/off as shown in FIG. 3, corresponding to each zoom lens position from the maximum telephoto position T to the macro end point MC2. The on/off information of each microswitch sw, -sw, for example, is r++ as shown in FIG.
The signal is weighted by z+rs and supplied to the A/D converter 16, where it is digitally coded to indicate each area as a position detection signal.

These position detection signals (position information codes) are shown as ■ to ■ in FIG. 3 for explanatory purposes.

Reference numeral 17 denotes a mode controller that is controlled through communication with the controller 10, and controls, for example, displaying normal mode and macro mode on the viewfinder of the video camera.

18 is a macro mode switch, and when the user operates this switch, the controller 10 shifts to macro mode and macro autofocus is executed. That is, the zoom lens is driven by the hill climbing control described above.

Reference numeral 19 denotes a power zoom switch, and the user arbitrarily drives the zoom lens in the normal mode, that is, when the focus lens is mountain-climbing controlled and autofocus is executed from the maximum telephoto region T to the maximum wide-angle region W ( This is an operation switch for the telephoto side (φ wide-angle side).

In this embodiment, where the autofocus control circuit system is configured as described above, the controller 1° drives the focus lens or zoom lens using the hill climbing control described above to achieve autofocus in the normal area and macro area. However, the position detection signal (position information code) obtained from the zoom lens position detection unit 15 of this embodiment is coded in five types (■ to ■) based on the on/off status of the microswitches SW1 to SWs. The macro endpoint areas MC, MCt are detected as the same position information code (■). Therefore, when the position information code (3) is detected during operation, the controller 10 must be provided with means for determining in which region the zoom lens is located, MC or MCb.

Needless to say, this determination is necessary during macro-autofocus operation and when the zoom lens is located within the macro area. (While operating in normal area (
In the normal mode), the zoom lens is controlled so as not to enter the macro region, and the zoom lens only shifts to the macro region when the user operates the macro mode switch 18 to enter the macro mode. Note that control to prevent the zoom lens from entering the macro area in the normal mode will be described later. ) During normal macro mode, the zoom lens is in the macro area, and in this case, if position information code ■ is obtained, the difference between the positions of MC and MCt is determined by the movement of the zoom lens at that time. You can tell by the direction. That is, the controller 10 performs hill climbing control based on the evaluation value data Dt, and the drive direction control signals S, S, and drive speed control signal Ss are generated to drive the zoom lens in autofocus mode. It knows the driving direction by itself. Therefore, when the drive direction control signal SF is output, the lens is being driven toward the telephoto side, and if position information code ■ is detected in this case, the zoom lens at that time is positioned in the macro end point area MC. It can be determined that Conversely, when the drive speed control signal Ss is output, the lens is being driven in the direction of the most macro side, and the detection of the position information code ■ in this case is determined to indicate the macro end point area MCゎ. can.

Therefore, during macro autofocus operation,
There is no particular problem even if the position information codes of both macro endpoint areas are the same. Detection of location information code MC, and M
It becomes impossible to determine which macro endpoint of Cb is indicated, or misjudgment occurs when (a) the position information code ■ is detected at the time of first power-on or setting, and (b)
) This is a case in which the zoom lens shifts from the normal area to the macro area when the macro mode switch 18 is operated and the macro mode is started.

Therefore, in this embodiment, in response to these cases, the malfunction prevention means in the controller 10 is configured by software.

That is, the controller 10 includes a drive means that drives the zoom lens toward the telephoto side when a detection signal of the macro end point region is obtained when the power is turned on, and a drive means that causes the zoom lens to escape from the macro end point region when the power is turned on. If the position detection signal obtained when the video camera is in the normal region indicates that it is in the normal region, the driving operation is stopped and the video camera is controlled to the normal mode, and
If the position detection signal indicates the macro area, the zoom lens is returned to the position when the power was turned on, and the video camera is controlled to the macro mode, and the macro mode switch 18 is operated. drive means for driving the zoom lens toward the macro side when the zoom lens enters the macro end point region; A determination means for determining whether or not the macro end point has been detected for the first time; and when the determination means determines that the macro end point has been detected for the first time, the zoom lens
and a blocking means for blocking macro end point detection information until passing through the macro end point area, configured by software,
The control shown in the flowcharts of FIGS. 5 and 6 is performed below.

(a) When the power is turned on (Fig. 5) When the power is turned on (Floo), the position information code detected by the zoom lens position detection unit 15 is ■,■
, ■, or ■, the zoom lens position can be grasped as is, so there is no problem with subsequent operation control. However, when the position information code ■ is obtained, as described above, it is not possible to distinguish between the MC and MCI of the macro end point area. Therefore, fFlol first drives the zoom lens toward the telephoto side.

F102). Then, when the macro end point area is exited (F103), the position information code is checked, and if position information code ■ is obtained, the zoom lens is stopped at that position, and the controller 10 thereafter controls various controls as normal mode. (F1051°) In other words, in this case, the zoom lens is located in the macro end point region MC when the power is turned on, and the position of MC is almost the same as the widest-angle position.

Therefore, there is no problem even if the system directly shifts to normal mode operation.

Further, when the position information code ■ is obtained in step F104, the zoom lens is returned to the position when the power was turned on by driving in the opposite direction for the same time as the drive in step F102, and the controller 10 moves to the current position of the zoom lens. is recognized as the macro end point area MCI,
From now on, control will be performed in macro mode (F
106).

The above operation prevents a position detection error when the power is turned on.

(b) At the start of the macro mode (Fig. 6) When the macro mode switch 18 is operated, the zoom lens is moved to the macro side (F200.F2011), and the zoom lens is controlled to climb the mountain in the macro area. , when entering the macro area, first enters the macro end point area MC, so a position detection code ■ is obtained.However, in this case, since the zoom lens is controlled to move in the macro direction by the drive direction control signal S, ,
As mentioned above, depending on the driving direction of the zoom lens, MC,
, M.C.

If this is determined, the position will be mistakenly determined to be the macro end point area MC. For this reason, when the position information code (■) is first detected during the drive in step F201, the detected information is blocked for a certain period of time by the blocking means to prevent it from being used as various system control information within the controller 10. fF202. F203). The cut-off period is set as the period required for the zoom lens to pass through the macro endpoint region MC.

When the cut-off period passes and the cut-off is released, the zoom lens is completely in the macro area at that point, so the position information code ■ is detected, or the position information code of the macro end point area MC is detected. (2) may be detected, but at this point, macro autofocus processing using hill climbing control is started (misjudgment in position detection can be avoided by controlling F2041° or higher).

Therefore, in this embodiment, accurate position detection is possible with the detection mechanism using three units of microswitches that generate the signals shown in FIG. It is not necessary to detect all areas (regions) using different position detection codes.

In addition, in normal mode, power zoom switch 1
9, it is necessary to prevent the zoom lens from entering the macro area even if the user continues to arbitrarily drive the zoom lens toward the wide-angle side. Therefore, as control corresponding to the power zoom switch 19, the control shown in the flowchart of FIG. 7 is executed in the controller 10.

That is, when the power zoom switch 19 is operated by the user (F300) and the operation is an operation to move the zoom lens toward the telephoto side, the controller 10 transmits the drive direction control signal SF and the predetermined drive speed control signal S5 to the zoom lens. The signal is output to the drive circuit 11b to cause the zoom lens to move in the telephoto direction. fF301-F30
2) If the operation is to the wide-angle side, the drive direction control signal S
, and a predetermined drive speed control signal S3 are output to the zoom lens drive circuit 11b to move it to the wide-angle side (F
301-F3031 When the macro end point area is reached during movement and the position information code (■) is detected, the zoom lens is driven toward the telephoto side by a preset return amount and stopped at the return position (F305).

In normal mode, when the zoom lens is not automatically driven by mountain climbing control, this control prevents the zoom lens from entering the macro position.
Good autofocus operation by the focus lens can be prevented from being inhibited.

[Effects of the Invention] As explained above, the video camera of the present invention can detect the position of the zoom lens with a small number of switch means because it detects both macro endpoint regions with the same detection signal, and can detect the position of the zoom lens even when the power is turned on. Since error prevention control is performed at the time when the zoom lens is positioned and when the macro mode is started, it is not difficult to distinguish which of the two macro endpoint areas the zoom lens position is, and this has the effect of preventing system malfunctions. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the autofocus control system of the video camera of the present invention, FIG. 2 is an explanatory diagram of mountain climbing control, and FIG. 3 is an example of a detection signal of the zoom position detection section of the present embodiment. FIG. 4 is a circuit diagram showing an example of encoding information from each detection signal, FIG. 5 is a flowchart showing control at power-on of this embodiment, and FIG. 6 is this embodiment FIG. 7 is a flowchart showing control at the time of starting the macro mode of this embodiment. FIG. 7 is a flowchart showing control at the time of power zoom operation of this embodiment. FIG. 8 is an explanatory diagram of the zoom lens position. 1 is a lens system, 2a is a focus lens motor, 2b is a zoom lens motor, 3 is a CCD image sensor, 10 is a controller, lla is a focus lens drive circuit, llb
1 is a zoom lens drive circuit, 5 is a zoom lens position detection section, and 18 is a macro mode switch. Diagram Diagram Dimensions 1 Multi-transformation McMcMcB Maximum Wu Desired 1 Wide-angle wide-angle macromacro product 40cti Straw diagram

Claims (2)

[Claims] (1) It has an autofocus function in a normal range from a telephoto state to a wide-angle state and a macro range from a wide-angle state to a close-up state, and the position detection signal of the zoom lens driven by autofocus in the macro range is detected in the macro range. In a video camera in which both end point positions are set to be the same, driving means for driving the zoom lens toward a telephoto side when a detection signal of a macro end point region is obtained at the start of operation; When it is detected that the zoom lens position is in a normal region based on a position detection signal obtained when the zoom lens position escapes from the macro end point region at the start of operation, the driving operation is stopped. Control to control the video camera to normal mode, and when it is detected that the zoom lens position is in the macro area, return the zoom lens to the zoom lens position when the power was turned on, and control the video camera to macro mode. A video camera comprising means and. (2) It has an autofocus function in a normal range from a telephoto state to a wide-angle state and a macro range from a wide-angle state to a state directly in front of the lens, and the position detection signal of the zoom lens that is autofocus driven in the macro range is In a video camera that has the same settings at both end points of the area, there is a drive means that drives the zoom lens toward the macro side when autofocus starts in the macro area, and a drive means that drives the zoom lens toward the macro side when autofocus starts in the macro area. a determining means for determining whether or not this is the first macro end point detection after the drive toward the macro side is started by the driving means; and a first macro end point detected by the determining means. A video camera comprising: blocking means for blocking macro end point detection information until the zoom lens passes through the macro end point region when it is determined that the zoom lens passes through the macro end point region.