JP3206205B2 - Optical adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical adjustment device for an automatic focusing device of a video camera, and more particularly to an optical adjustment device for an image pickup device at an optical adjustment site having vibration.

[0002]

2. Description of the Related Art A method of adjusting a zoom lens of a video camera in which a focusing lens position is controlled so that a high frequency component of a video signal is maximized to obtain an in-focus state is performed as follows. Was.

An image pickup device of a video camera (for example, CC
The optical image formed in D) is converted into a distribution of accumulated charges generated in the light receiving portion of the CCD according to the intensity and the exposure time. The stored charges are sequentially transferred using vertical and horizontal CCDs to generate time-series video signals. A predetermined high-frequency component is extracted from the time-series video signal by a high-pass filter or a band-pass filter. The extracted high frequency components are detected and integrated. The output of the integrator has a maximum value when the focusing lens is in a focused state, and decreases as the focusing lens deviates from the focused state. Hereinafter, the output of the integrator is referred to as a focus signal.

As described above, the focus signal depends on the intensity of the optical image and the exposure time of the CCD.
In the case where the length is long, if there is a vibration during the exposure, a light beam irradiating a certain pixel (light receiving portion of the CCD) irradiates another nearby pixel due to the vibration. In other words, a plurality of congruent optical images are generated by the change of the irradiation position of the light beam due to the vibration
An optical image equivalent to an image obtained by shifting the positions little by little is obtained. That is, a video signal is passed through a so-called low-pass filter in which components with higher spatial frequencies are suppressed.

Therefore, if an external vibration is applied to the video camera being adjusted while controlling the focusing lens so that the focus signal is maximized, the focus signal changes suddenly and a false focus is obtained. May be detected. Conventionally, in order to prevent such a malfunction, a device has been devised to reduce the vibration to a predetermined amount or less, for example, by incorporating a vibration suppressing device into an adjusting device. Therefore, the equipment for optical adjustment is also large, and the equipment cost is not only expensive, but also it is not easy to change the equipment.

[0006] In this case, there is no known example in particular of an adjusting device, but an automatic focusing device for controlling the position of a focusing lens so that a focus signal is maximized is described in Japanese Patent Application Laid-Open No. 58-15893. Automatic focusing device.

[0007]

In the above prior art, optical adjustment of a video camera is performed while preventing vibration of adjustment equipment.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical adjustment device for a video camera which can tolerate vibration of adjustment equipment.

[0009]

SUMMARY OF THE INVENTION The present invention provides a zoom lens to be adjusted, a CCD image pickup device for forming an optical image of the zoom lens, a camera circuit for converting the output of the CCD image pickup device into a video signal, and a high image signal. A focus voltage generating circuit for extracting, detecting, and integrating a frequency range component, a shutter circuit for setting an exposure time of a CCD image sensor, a control circuit for operating a zoom lens, reading a focus voltage, and setting a shutter speed, and control A personal computer that performs automatic adjustment by communicating data with circuits (hereinafter abbreviated as personal computer)
And a collimator device for forming an object image at infinity and a subject illumination device of the collimator device.

[0010]

The operation of the present invention will be described with reference to FIGS. A collimator image is used as a subject image. First,
The shutter speed of the electronic shutter of the CCD image sensor of the camera is set to a speed at which no image blur occurs due to the vibration of the adjustment environment. Normally, the shutter speed of a video camera is 1
The setting is from 1/60 second to 1/100 second, but in an environment with vibration such as back focus adjustment and zoom tracking adjustment of the lens, it is 1/1000 second to 1/2000 second.
Seconds are appropriate.

After setting the shutter speed, the back focus is adjusted. That is, a variable power lens (not shown) of the lens is positioned at a predetermined zoom position, and that state is maintained. The high frequency components are extracted from the video signal of the camera using a band-pass filter, detected, integrated, and the focal voltage is read by a personal computer. The personal computer controls the focusing lens position of the lens so that the focal voltage becomes the maximum value, and obtains the in-focus position at the subject at infinity.
In these series of operations, the fluctuation of the focal voltage due to the vibration of the adjustment environment will be described with reference to FIG.

In FIG. 2, if vibration occurs during accumulation of photoelectric charges in the CCD image pickup device, the light quantity distribution on the CCD light receiving surface changes. That is, from time t1 to time tn
Consider the case of exposing to

In FIG. 2, (A) is a light amount distribution when there is no vibration, and (B) is a light amount distribution when there is vibration, and shows a positional deviation when changing from time t1 to tn.
(C) is an averaged light amount distribution of the light amount distribution shown in (B), and shows a substantial light amount distribution when there is vibration.

As shown in (C), the light amount distribution averaged for the exposure time is the average light amount distribution of each light amount distribution from time t1 to time tn. Accordingly, in the case of a low-speed shutter as in the related art, the averaged light amount distribution is obtained by applying a low-pass filter to the light amount distribution at each instant (the true light amount distribution of the subject). As a result, if vibration is applied during driving of the focusing lens so that the focus voltage becomes the maximum, the focus voltage decreases as shown by the broken line in FIG. As a result, the lens position deviates from the true focal point (E), which causes a poor adjustment.

However, when the CCD image sensor is controlled by a high-speed shutter, the fluctuation range of the light amount distribution on the CCD light receiving surface becomes smaller at a shutter speed ratio than when the low-speed shutter is used. As a result, the above-described averaged light amount distribution approaches the light amount distribution at each instant.
Therefore, even when vibration is applied during driving of the focusing lens so that the focal voltage is maximized, the focal point (E) is detected without lowering the focal voltage as shown by the solid line in FIG. Can be adjusted.

Similarly, in the case of zoom tracking adjustment in a vibrating environment, since the in-focus position for an object at infinity for each of a plurality of zoom positions can be obtained, a micro-computer built in a personal computer or a video camera can be obtained. The adjustment is performed by performing a correction calculation of the tracking error by a computer.

The adjustment using an object at infinity has been described above.
The same applies.

The illuminance of the subject of the above-described automatic adjustment device should be changed when the model of the video camera is changed. The illuminance corresponding to the model is determined based on the identification data of the camera, and is determined in advance. An efficient adjusting device is realized by remotely controlling a control device of the subject illuminance by a personal computer in order to obtain the determined illuminance.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described below. FIG. 1 is a block diagram of a signal processing unit of an optical adjustment device applied to the automatic focusing device of the present invention.
Is a front lens, 2 is a variator lens that changes the zoom magnification, 3 is a diaphragm device that adjusts the amount of incident light of the photographing optical system,
4 is a focus lens for forming a subject image, 5 is a CCD
A camera circuit for converting the photoelectric signal from the CCD 5 into a video signal which is easy to process by an automatic focusing device and a video processing means (not shown); and 7 a high-pass filter for extracting a high frequency component of the video signal. Reference numeral 8 denotes a detection circuit for detecting the output of the high-pass filter 7, reference numeral 9 denotes an integration circuit for integrating the detected signal for a predetermined period, and the integrated output is hereinafter referred to as a focus voltage. Reference numeral 10 controls the electric exposure time of the CCD 5. A shutter circuit, 11 is a microcomputer (hereinafter abbreviated as AF microcomputer) for controlling the automatic focusing device, 12 is a motor driver for controlling the position of the focus lens 4, and 13 is according to the output of the motor driver 12. A focus motor 14 for moving the position of the focus lens 4, and a motor 14 for controlling the position of the variator lens 2. The driver, 15 motor driver 1
A zoom motor for moving the position of the variator lens 2 in accordance with the output of 4, a zoom encoder 16 for detecting the position of the variator lens 2, an adjustment personal computer 17 for controlling the AF microcomputer 11 for optical adjustment, and 18 An illumination control device for controlling the illumination illuminance of an adjustment chart (not shown) as a subject of the photographing lens; 19, an illumination bulb for the adjustment chart; 20, an AF microcomputer 11 and the adjustment personal computer 1
Reference numeral 21 denotes a communication line for communicating with the microcomputer 7, and 21 denotes a signal line for transmitting illuminance information of a video signal to the AF microcomputer.

From the adjusting personal computer 17, the AF microcomputer 1
1 is sent to the CCD 5 to increase the shutter speed. Next, a command for positioning the variator lens 2 at a predetermined position is sent from the adjustment personal computer 17 to the AF microcomputer 11.

In this state, the focus voltage obtained by the integration circuit 9 from which the high frequency components of the video signal are extracted is calculated by AF.
The microcomputer 11 monitors the position and controls the position of the focus lens 4 via the motor driver 13 so that the focal voltage becomes maximum. As a result, the position of the focus lens 4 corresponding to the focal point at the predetermined zoom position at the predetermined object distance is determined. In addition, CC
Since the shutter speed of D5 is increased, it is not affected by environmental vibration.

In FIG. 4, the horizontal axis indicates the zoom position, that is, the position of the variator lens 2, and the vertical axis indicates the extension amount of the focus lens 4 for maintaining a focused state at a predetermined object distance. The position of the variator lens 2 is detected by connecting the output of a zoom encoder 16 composed of a sliding resistor linked to the variator lens 2 to the input of the AF microcomputer 11, and the position is determined as the zoom position.

Each point shown in FIG. 4 indicates the extension amount of the focus lens 4 at the zoom position evaluated by optical adjustment. As described above, the focal point at each zoom position is sequentially obtained, and the correction amount is calculated.

FIG. 5 shows one embodiment of the optical adjustment. In the drawing, reference numeral 31 denotes an object set at a predetermined distance, 32 denotes an interface with the adjustment personal computer 17, 33 denotes a video camera to be adjusted, 34 denotes a frame of an adjustment line, and 35 denotes a base plate on which the video camera is mounted. . As shown in FIG. 5, the adjustment personal computer 17 is connected to the video camera 33 via the interface 32, and sequentially adjusts the video cameras arranged in order.

The illuminating means for illuminating the chart as the subject adjusts the illuminance of the bulb 19 by the illumination control device 18. As a method for this adjustment, the adjustment personal computer 17 determines identification data such as the type of video camera (not shown) and controls the lighting control device 18.

In FIG. 1, the illuminance information from the video signal is transferred to the adjusting personal computer 17 via the AF microcomputer 11 via the signal line 21 and the illumination control device is controlled so that the illuminance becomes predetermined. In addition, it is possible to cope with a change in the illuminance of the lighting bulb.

[0027]

As a result of the present invention, even if there is vibration in the optical adjustment device, there is no change in the focus voltage for detecting the focal point because the high-speed shutter device is used, so that the optical adjustment device does not require a vibration proof structure. The device can be constructed at low cost.

Further, since the high-speed shutter device is a device equipped as a standard function in the video camera, it is not necessary to use a new device for optical adjustment, and the cost can be reduced in this regard.

Further, according to the present embodiment, since the illuminance of the object for optical adjustment is controlled by the adjustment personal computer, even if the model of the video camera on the line is changed in the middle, the appropriateness can be obtained without human intervention. Can be set to illuminance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an effect of a high-speed shutter according to the present invention.

FIG. 3 is an explanatory diagram of an effect of a high-speed shutter according to the present invention.

FIG. 4 is an explanatory diagram of a zoom adjustment according to the present invention.

FIG. 5 is an external view of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... front lens, 2 ... variator lens, 4 ... focus lens, 5 ... CCD image sensor, 6 ... camera circuit, 7 ... high-pass filter, 8 ... detection circuit, 9 ... integration circuit, 10 ... shutter circuit, 11 ... AF Microcomputer, 12 motor driver, 13 focus motor, 14 motor driver, 15 zoom motor, 16 zoom encoder, 17 personal computer for adjustment, 18 lighting controller, 19 light bulb for lighting, 21 communication line, 22 ... signal line.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Sagara 1410 Inada, Katsuta-shi, Ibaraki Pref., Hitachi, Ltd. AV Equipment Division (72) Inventor Yoshihiro Todaka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. Inside the Video Media Research Laboratory (72) Inventor Ichiro Osaka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi Video Media Research Laboratory (72) Atsushi Shiokawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Japan (72) Inventor Hiroshi Chiba 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture In-house Hitachi Media Media Research Laboratories (56) References JP-A-6-133204 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/232 G02B 7/28 G02B 7/36 H04N 5/238

Claims (7)

(57) [Claims] 1. An optical adjustment apparatus for an image pickup apparatus having a shutter device, wherein a position of a focusing lens is adjusted while a shutter speed of the shutter is set to a high speed, and focus information for detecting a focal point is obtained. An optical adjustment device characterized by being obtained. 2. The optical adjustment device according to claim 1, wherein the shutter device is realized by making a charge accumulation period of a photoelectric conversion element included in the imaging device variable. 3. The optical adjustment device according to claim 1, wherein the subject illuminance of the subject for optical adjustment of the imaging device is controlled by a control unit that can adjust the illuminance to a predetermined illuminance. 4. The image processing apparatus according to claim 1, further comprising: determining means for determining the type of the imaging device; and control means for controlling the subject illuminance of the subject to a predetermined illuminance based on the determination result of the determining means. 4. The optical adjustment device according to 1, 2, or 3. 5. In the optical adjustment of an image pickup apparatus, camera circuit means for converting a photoelectric conversion signal of an image of a subject into a video signal as a means for detecting a focal point, and a high frequency band of a video signal output from the camera circuit means. A high-pass filter or a band-pass filter for extracting a frequency component, a detecting means for detecting an output of the high-pass filter or the band-pass filter, an integrating means for integrating an output of the detecting means for a predetermined period,
The optical adjustment device according to claim 1, further comprising a focus determination unit configured to determine a maximum value of an integration output signal of the integration unit as a focal point of a subject image. 6. The optical adjustment device according to claim 1, further comprising a zoom lens as the subject image forming device. 7. The optical adjustment device according to claim 1, wherein the shutter speed is a high-speed shutter of 1/250 second or less.