JP2002027310A - Image pickup system and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further miniaturize a device configuration by easily, accurately, and automatically adjusting the relative position with the image pickup optical system of an image pickup means within a specific tolerance in a simple configuration. SOLUTION: Before an image pickup operation, information read from a storage means 42, namely the positional difference between a reference value obtained based on a test chart for adjusting positions and an image pickup element for reference, is stored in a storage means in the format of error information corresponding to each specific temperature regarding the relative position with the image pickup optical system 8 of an image pickup element 1, and the relative position with the image pickup optical system 8 of the image pickup means 1 is adjusted within a specific tolerance by the drive of the drive means 11 and 12 based on the information.

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 system having an image pickup means such as an image pickup optical system and a photoelectric conversion element.

[0002]

2. Description of the Related Art FIG. 9 shows a typical configuration diagram of a conventional imaging system, and a schematic operation will be described based on the configuration diagram. In this imaging system, a focal length adjusting optical system L1 for adjusting an imaging angle of view, a correction optical system L2 according to the movement of the L1, a shift optical system L3 for camera shake correction, and a diaphragm mechanism for adjusting the amount of incident light ( Iris), a subject image is formed on the image sensor 1 by the imaging optical system 8 having the focus position adjusting optical system L4 for performing focus adjustment. The subject image is photoelectrically converted by the image pickup device 1 into an electric signal, and processed into a color video signal by the video camera signal processing means 3. While this color video signal is output, luminance information is mainly supplied to the exposure control (AE) means 4 and the focus adjustment (AF) means 2 to generate respective control signals.

The AE means 4 controls the storage time (so-called shutter speed) of each image of the image pickup device 1 and the aperture mechanism, and the AF means 2 controls the focus position adjusting optical system L4.

The shake detecting means 7 is composed of an acceleration sensor or the like, and detects a hand shake state. Using this detection output, the shift optical system driving means (AS / IS) drives the shift optical system L3 to reduce blur.

[0005] An angle-of-view adjusting (zoom) means 5 receives an operation instruction signal for adjusting the angle of view of the imaging as required by the user, reads out an electronic cam curve from a memory (not shown), and links the optical systems L1 and L2. While controlling.

[0006]

As described above, in recent years, with the rapid progress of miniaturization of the imaging system, a versatile and high-performance imaging system can be realized in a small size, but on the other hand, the mounting of the imaging device is difficult. Extremely high precision is required.

For example, as shown in FIG. 10, the imaging optical system 8 depends on the manufacturing accuracy of parts and mounting errors in the manufacturing process.
May be inclined from the vertical. In this case, as the miniaturization of the system configuration progresses,
It is difficult to keep the angle θ within an allowable range, and it is becoming increasingly difficult to perform the angle adjustment with high accuracy corresponding to the currently required miniaturization.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to easily and accurately automatically adjust the relative position of an image pickup means to an image pickup optical system within a predetermined allowable range with a simple configuration. It is an object of the present invention to provide an imaging system and a control method thereof that can sufficiently cope with further downsizing of the device configuration.

[0009]

According to the present invention, there is provided an image pickup system comprising: an image pickup optical system; an image pickup unit for performing photoelectric conversion processing of incident light from the image pickup optical system; and a relative position of the image pickup optical system of the image pickup unit. A storage unit for storing information relating to a position; and a position adjustment unit for adjusting the position of the imaging unit. Based on the information read from the storage unit, the position adjustment unit is driven by driving the position adjustment unit. It is characterized in that the relative position with respect to the imaging optical system is adjusted.

In one embodiment of the imaging system of the present invention,
The storage unit stores information on a positional difference between a reference value obtained based on a predetermined position adjustment pattern having predetermined horizontal and vertical frequency components and a reference imaging unit.

In one aspect of the imaging system of the present invention,
The position of the reference imaging unit is adjusted in the horizontal and vertical directions so that the frequency components in the horizontal and vertical directions are respectively maximized by the predetermined pattern, thereby obtaining the information on the positional difference.

In one aspect of the imaging system of the present invention,
The storage unit stores, for the positional difference, error information corresponding to each predetermined temperature regarding a relative position of the imaging unit with the imaging optical system.

In one embodiment of the imaging system of the present invention,
The imaging optical system is provided interchangeably.

In one embodiment of the imaging system of the present invention,
A first storage unit provided on the imaging optical system side for storing a difference from the reference value of the imaging optical system, and a first storage unit provided on the imaging unit side and the reference value of the imaging unit; And second storage means for storing the difference.

In one embodiment of the imaging system of the present invention,
The information in the first and second storage units is integrated by data communication, and the relative position of the imaging unit with the imaging optical system is adjusted.

A method of controlling an image pickup system according to the present invention is directed to an image pickup system including an image pickup optical system and image pickup means for performing photoelectric conversion processing on incident light from the image pickup optical system. Information relating to a relative position with respect to the system is stored, and the relative position of the imaging unit with the imaging optical system is adjusted by driving the position adjustment unit based on the information.

In one aspect of the control method of the imaging system according to the present invention, the information includes a reference value obtained based on a predetermined position adjustment pattern having predetermined horizontal and vertical frequency components. This is information on a positional difference from the reference imaging unit.

In one embodiment of the control method of the image pickup system of the present invention, the reference image pickup means is provided in the horizontal direction and the vertical direction such that the frequency components in the horizontal and vertical directions are respectively maximized by the predetermined pattern. The position is adjusted to obtain information on the positional difference.

In one aspect of the control method of the imaging system according to the present invention, the information is error information corresponding to the positional difference with respect to a relative position of the imaging means with respect to the imaging optical system for each predetermined temperature. is there.

In one embodiment of the control method of the imaging system according to the present invention, the imaging optical system is provided so as to be exchangeable.

In one aspect of the control method of the image pickup system according to the present invention, the difference between the reference value of the image pickup optical system and the reference value of the image pickup means is set on the image pickup optical system side. Are stored as the information.

In one aspect of the control method of the image pickup system of the present invention, the image pickup optical system side and the image pickup means side are integrated by data communication, and the relative position of the image pickup means with respect to the image pickup optical system is adjusted. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic diagram showing the overall configuration of an imaging system according to the present embodiment. In this imaging system, reference numeral 1 denotes an imaging element including a photoelectric conversion element such as a CCD or CMOS, 8 denotes a focal length adjusting optical system L1 for adjusting an imaging angle of view, a correction optical system L2 corresponding to the movement of the L1, and a camera shake correction. Optical system L3, an aperture mechanism (Iris) for adjusting the amount of incident light, and a focus position adjusting optical system L4 for adjusting focus.

Further, reference numeral 2 denotes a focus adjusting (AF) means for controlling the focus position adjusting optical system L4, 3 denotes a signal processing means for receiving an image pickup signal from the image pickup element 1 and outputting an image, and 4 denotes an image pickup element 1 Exposure control (AE) means for controlling the accumulation time (so-called shutter speed) for each screen and the aperture mechanism;
Is an input of an operation instruction signal for adjusting the imaging angle of view as required by the user, reads an electronic cam curve from a memory (not shown), and controls the angle of view (zoom) by controlling the optical systems L1, L2, and L4 in conjunction with each other. Means.

Further, reference numeral 7 denotes an acceleration sensor or the like, which is a shake detecting means for detecting a camera shake state, and 6 is a shift optical system which receives a signal from the shake detecting means 7 and drives a shift optical system L3 to reduce the shake. System driving means (AS / IS).

Reference numeral 42 denotes storage means (error memory) for storing information on the relative position of the image pickup device 1 with respect to the image pickup optical system 8. As the information, as will be described later, a positional difference between a reference value obtained based on a position adjustment test chart having predetermined frequency components in the horizontal direction and the vertical direction and a reference imaging device is obtained. For example, error information corresponding to each predetermined temperature regarding the relative position of the image sensor 1 with respect to the image pickup optical system 8 is used. Reference numeral 61 denotes a temperature sensor for measuring the temperature inside the apparatus.

Further, 12 and 11 are X-axis (horizontal), respectively.
Is a driving unit for controlling the position of the image sensor 1 in the direction and the Y-axis (vertical) direction. The relative position of the image sensor 1 with respect to the imaging optical system 8 is determined based on information in the storage unit 42 within a predetermined allowable range. Adjust within.

Then, based on information from the storage means 42 and the temperature sensor, the system control means 9
And the driving means 11 and 12 are controlled.

The feature of the imaging system of the present embodiment is that, prior to the imaging operation, based on the information read from the storage means 42, the driving means 11 and 12 are driven to move the imaging means 1 relative to the imaging optical system 8 relative to the imaging optical system 8. It is to adjust the target position within a predetermined allowable range (angle correction).

FIG. 2 is a schematic diagram showing the basic concept of adjusting the angle of the image pickup device 1. The angle adjustment needs to be performed on the imaging screen in the X-axis and Y-axis directions. In an effective image circle including an effective image formed by the imaging optical system 8,
The largest rectangular imaging area inscribed is area A, and 2
Area B is a safe area without vignetting in consideration of shaft adjustment work. Here, an angle θ (θx, θx) formed between the optical axis of the imaging optical system 8 and the imaging device 1 with respect to each of the X axis and the Y axis.
An imaging signal is generated and output with the effective imaging area adjusted for y) as area B.

Referring to FIG. 3, a method for measuring the difference between the positional information, that is, the error from the reference value, will be described below. When the imaging optical system 8 having the above-described configuration is measured, X A test chart 43 for measurement having respective frequency components of the Y axis and the Y axis is imaged on a reference image sensor 40 in which the imaging optical system 8 is installed at a reference mounting position, and this information is photoelectrically converted and output. I do. The photoelectric conversion signal is converted into a color (or monochrome) video signal by a well-known video camera signal processing unit, supplied to an evaluation unit 41, and the relative position between the imaging optical system 8 and the reference imaging element 40 is evaluated. The reference image pickup device 40 is inclined with respect to the X axis and the Y axis, and the inclination angle having the highest frequency component is detected, and this angle (deviation from the reference value) is stored in the storage means 42 provided in the imaging optical system unit. I do. This storage means 42 stores the EE
A non-volatile memory such as a PROM, which can be read from a system microcomputer on the camera side having an image pickup device to be combined when assembling an image pickup system.

Similarly, it is possible to measure the error of the mounting position of the image pickup device based on the image pickup optical system serving as a reference.
A storage unit for storing the error information of the image sensor may be provided. As will be described later, in the interchangeable lens system, as described later, it is possible to construct an effective system by separately providing each of them.

FIG. 4 shows the concept of adjusting the integrated value in the screen in two directions of the X axis and the Y axis. Here, hill-climbing control using a so-called TV signal is performed for the X-axis and the Y-axis, and optimization of the entire screen is executed.

For example, fixing the Y axis to an arbitrary value, first,
The hill-climbing control is performed so that the high-frequency component in the X-axis direction becomes the highest value. Next, the hill-climbing control of the Y-axis component is executed in a state where the X-axis value is fixed to the vertex of the X-axis, and the vertex value on the X-axis at this time and the inclination angle θx corresponding to the vertex value on the Y-axis , Θy are stored.

In order to further improve the accuracy, it is necessary to correct a change in the tilt angle due to a temperature change in the apparatus. For this purpose, error information corresponding to a plurality of temperatures is stored in the storage unit 42.
To be stored. As one method, a table may be provided for each temperature and each parameter value may be stored. It is considered practically sufficient to store 5 to 6 measurement temperatures at 20 ° C. centered at room temperature of 20 ° C. For example, the temperature settings are -20 ° C, 0 ° C, 20 ° C, 40 ° C, and 60 ° C.

In this case, first, the temperature in the apparatus is measured by the temperature sensor 61, and among the various parameter values for each temperature stored in the storage means 42 in advance, the temperature closest to the measured temperature is determined. The error information is read from the table, and the relative position is corrected according to the value. As the correction method,
The relative positions of the imaging optical system and the imaging device are adjusted by adjusting the mounting inclination angles of the imaging device 1 in the X direction and the Y direction by the driving units 11 and 12.

Other adjustment systems are also conceivable, as described below. At the time of factory adjustment after incorporating the imaging optical system 8 and the imaging device 1 into the main body, the above-described relative position error measurement operation is performed, and the driving amount D from the driving reference point of the driving means 11 and 12 is calculated.
The x and Dy information is measured for each of a plurality of temperatures and stored in the storage means 42, and before the imaging operation, the information is read out by the system control means 9 and the driving means 1
The relative position correction of the image pickup means 1 is performed by 1 and 12.

The above position adjustment procedure is shown in FIG. 5 as an adjustment flowchart, and a simple process for each step (S1 to S7) will be described.

First, when the system control means 9 detects that the power is turned on (S1), the position adjustment is started (S2), and the information is read from the storage means 42 (S3). Adjustment in the X-axis direction is performed based on the information (S4), and adjustment in the Y-axis direction is similarly performed based on the information. At this time, the inclination angle is corrected based on the above-mentioned device internal temperature (S5). Upon completion of the adjustment in both axial directions (S
6), the adjustment operation ends (S7). Thus, the initial adjustment is completed, and the steady imaging can be started.

As described above, according to the imaging system of the present embodiment, the relative position of the imaging device 1 and the imaging optical system 8 can be easily and accurately adjusted within a predetermined allowable range with a simple configuration. This makes it possible to sufficiently cope with further downsizing of the device configuration.

Further, by storing information for position adjustment for each predetermined temperature in the storage means 42, it is possible to cancel a temporal change due to a temperature change.

(Second Embodiment) Next, a second embodiment of the present invention will be described. This imaging system has a first
In this embodiment, the initial adjustment is performed in the same manner as in the first embodiment, but is different in that the imaging optical system 8 is replaceable. In addition,
Constituent members and the like similar to those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 6 is a schematic diagram showing the overall configuration of the imaging system of the present embodiment. This imaging system is roughly divided into a lens unit and a camera unit, each of which includes system control means 16 and 18 each comprising a microcomputer.
Correspondingly, storage means (error memory) is provided on the lens unit side.
Reference numeral 17 denotes a storage unit (error memory) 19 provided on the camera unit side, and data communication is performed between the system control units 16 and 18.

Prior to the steady imaging operation, the system control means 16 on the lens unit side first measures the temperature in the lens with the temperature sensor 81, and stores a plurality of temperature values stored in the error memory 17 in advance. Among the various parameter values, the error information (information obtained by correcting the position adjustment information based on the measured temperature) from the table of the value closest to the measured temperature is read out, and the value is read out by the system on the lens unit side. The data is transmitted from the control unit 16 to the system control unit 18 on the camera unit side.

At substantially the same time as this operation, the system control means 18 of the camera section measures the temperature in the camera body by the temperature sensor 82 and stores various temperatures for a plurality of temperatures stored in the error memory 19 in advance. From among the parameter values, error information (information obtained by correcting the position adjustment information based on the measured temperature) from the table of the value closest to the measured temperature is read out, together with the value transmitted from the lens. The position of the image sensor 1 is controlled by the correction method described later.

As described above, since the temperature sensor and the error memory table are stored in each of the camera section and the lens section corresponding to a plurality of temperatures, more appropriate correction can be performed even when the camera temperature and the lens temperature are different. You can do it.

Here, a subject image is formed on the image pickup device 1 by the image pickup optical system 8, photoelectrically converted by the image pickup device 1, and processed into a color video signal by the video camera signal processing means 3. The processed video signal is output, and the luminance information is mainly supplied to the AE unit 4 and the AF unit 2 to generate respective control signals and input to the system control unit 18. Control data from the AE unit 4 and the AF unit 2 are transmitted from the system control unit 18 to the system control unit 16 on the lens unit side, and control the Iris and the focus position adjusting optical system L4. The AE unit 4 also controls the accumulation time of each image of the image sensor 1 as necessary.

The camera shake state is detected on the lens unit side.
The blur is detected by the blur detecting means 7 such as an acceleration sensor, and the optical system L3 is driven by the shift optical system driving means (AS / ls) to reduce blur.

Further, when an operation instruction signal for adjusting the imaging angle of view is input to the system control means 18 as required by the operator, the signal is transmitted to the system control means 16 on the lens unit side and provided on the lens unit side. An electronic cam curve is read from a memory (not shown), and control is performed while the optical systems L1, L2, and L4 are linked.

Here, the correction method will be described with reference to the error correction table of FIG. X axis error: error angle and shift amount from the reference position in the X axis direction Y axis error: error angle and shift amount from the reference position in the Y axis direction Z axis error: error angle and shift from the reference position in the Z axis direction The amounts L1-C1, L3-C3, and L5-C5 are calculated, the relative error angles are obtained, the relative shift amounts of L2-C2, L4-C4, and L6-C6 are obtained, and correction data is set.

FIG. 6 shows the initial adjustment procedure in this embodiment.
Is shown as an adjustment flowchart, and each step (S1 to
A simple process for each S10) will be described. Here, an example of a data communication procedure between the system control unit 16 on the lens unit side and the system control unit 18 on the camera unit side will be described.

First, when the lens attachment is detected (S
1) The error information stored in the storage unit 17 on the lens unit side is transmitted to the camera side (S2). Subsequently, this is received by the system control unit 18 on the camera unit side (S3), and error information is read from the storage unit 19 on the camera unit side (S3).
4) Compiling with the error information on the lens unit side, each correction data is generated in accordance with the above procedure. X based on the correction data
The adjustment in the axial direction is performed (S5), and the adjustment in the Y-axis direction is performed based on the correction data (S6). When the adjustment is completed, the flow ends (S7).

As described above, according to the present embodiment, in addition to the various embodiments of the first embodiment, the data relating to the adjustment work is also transmitted to the system control on the camera section side in the lens-interchangeable imaging system. By enabling communication between the unit 18 and the system control unit 16 on the lens unit side, the relative position between the optical system and the image sensor can be optimized even when an imaging optical system having any characteristics is attached. In addition, it is possible to eliminate an inappropriate imaging screen (a so-called one-sided blur) in which a partially blurred portion is left, thereby enabling good imaging. Moreover, by providing a storage unit in each of the lens unit and the camera unit, a highly compatible system can be constructed.

Further, since the temperature sensor and the error memory table are stored in both the camera section and the lens section corresponding to a plurality of temperatures, more appropriate correction can be executed even when the camera temperature and the lens temperature are different. .

[0056]

According to the present invention, the relative position of the image pickup means with respect to the image pickup optical system can be easily and accurately adjusted within a predetermined allowable range with a simple structure. It is possible to cope with the change. In addition, it is possible to appropriately correct the temperature change during shooting,
For example, by performing a correction process during a shooting pause or when the power is turned on again, it is possible to cope with a temporal change during use.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an overall configuration of an imaging system according to a first embodiment.

FIG. 2 is a schematic diagram showing a basic concept of angle adjustment.

FIG. 3 is a schematic diagram showing a method of measuring and storing an initial position using a reference imaging element.

FIG. 4 is a schematic diagram showing a concept of adjusting an integrated value in a screen in two directions of an X axis and a Y axis.

FIG. 5 is a flowchart illustrating initial adjustment.

FIG. 6 is a schematic diagram illustrating an overall configuration of an imaging system according to a second embodiment.

FIG. 7 is a table showing an error memory table.

FIG. 8 is a flowchart showing an initial adjustment.

FIG. 9 is a schematic diagram showing the overall configuration of a conventional imaging system.

FIG. 10 is a conceptual diagram illustrating a change in an angle between an optical axis of an imaging optical system and an imaging element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image sensor 2 Focus adjustment (AF) means 3 Signal processing means 4 Exposure control (AE) means 5 Angle-of-view adjustment (zoom) means 6 Shift optical system drive means (AS / IS) 7 Shake detection means 8 Imaging optical system 9, 16, 18 System control means 11, 12 Driving means 17, 19, 42 Storage means (error memory) 40 Reference image sensor

Claims (14)

[Claims] An imaging optical system; an imaging unit configured to perform a photoelectric conversion process on incident light from the imaging optical system; and a storage unit configured to store information on a relative position of the imaging unit with the imaging optical system. A position adjusting unit that adjusts the position of the imaging unit, and adjusts a relative position of the imaging unit with the imaging optical system by driving the position adjustment unit based on information read from the storage unit. An imaging system, characterized in that: 2. The image processing apparatus according to claim 1, wherein the storage unit stores a reference value obtained based on a predetermined position adjustment pattern having predetermined horizontal and vertical frequency components and a positional difference between the reference value and the reference imaging unit. The imaging system according to claim 1, wherein information is stored. 3. The information on the positional difference is obtained by adjusting the position of the reference imaging means in the horizontal and vertical directions so that the frequency components in the horizontal and vertical directions are respectively maximized according to the predetermined pattern. The imaging system according to claim 2, wherein 4. The apparatus according to claim 2, wherein said storage means stores error information corresponding to each predetermined temperature regarding a relative position of said image pickup means with respect to said image pickup optical system. Or the imaging system of 3. 5. The imaging system according to claim 1, wherein the imaging optical system is provided so as to be exchangeable. 6. A storage device, comprising: a first storage device provided on the imaging optical system side for storing a difference from the reference value of the imaging optical system; and a storage device for the imaging device provided on the imaging device side. The imaging system according to claim 5, further comprising a second storage unit that stores a difference from the reference value. 7. The apparatus according to claim 6, wherein the information in the first and second storage units is integrated by data communication, and a relative position of the imaging unit with respect to the imaging optical system is adjusted. Imaging system. 8. A method for controlling an imaging system, comprising: an imaging optical system; and an imaging unit that performs photoelectric conversion processing on incident light from the imaging optical system, wherein a relative relationship between the imaging unit and the imaging optical system is provided. A method for controlling an imaging system, wherein information on a position is stored, and a relative position of the imaging unit with the imaging optical system is adjusted by driving the position adjustment unit based on the information. 9. The information includes information on a positional difference between a reference value obtained based on a predetermined pattern for position adjustment having predetermined horizontal and vertical frequency components and a reference imaging unit. The control method for an imaging system according to claim 8, wherein 10. The information on the positional difference by performing position adjustment of the reference imaging means in the horizontal direction and the vertical direction such that the frequency components in the horizontal direction and the vertical direction are respectively maximized by the predetermined pattern. The method according to claim 9, wherein 11. The information processing apparatus according to claim 9, wherein the information is error information corresponding to the positional difference with respect to a relative position of the imaging unit with the imaging optical system for each predetermined temperature. 3. The control method of an imaging system according to claim 1. 12. The method according to claim 9, wherein the imaging optical system is provided to be exchangeable. 13. The imaging optical system stores the difference from the reference value of the imaging optical system, and the imaging unit stores the difference from the reference value of the imaging unit as the information. The method for controlling an imaging system according to claim 12, wherein: 14. The apparatus according to claim 13, wherein the imaging optical system side and the imaging unit side are integrated by data communication, and a relative position of the imaging unit with the imaging optical system is adjusted. An imaging system control method.