JPH11190864A - Imaging device with tilt mechanism, method, and storage medium - Google Patents

Abstract

(57) [PROBLEMS] To control a tilt mechanism for rotating an input medium for an optical image about a fixed rotation center based on an image signal obtained from an image sensor to focus on a plurality of subjects. In this case, a plurality of subjects having different subject distances are surely focused without being affected by the position of the subject. In an image pickup apparatus provided with a tilt mechanism for rotating an input medium for an optical image about a fixed rotation center, a high-frequency component of an image signal obtained from an image pickup element at a lens focus position from a close to infinity. Detect the maximum value of
Drives and controls the tilt mechanism so that the distance between the lens focus positions of multiple maxima corresponding to multiple subjects with different subject distances is minimized, and then drives and controls the tilt mechanism so that the maximal value is maximized I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt correction technique in a video camera, an electronic still camera, or the like, in which a lens or an image sensor is rotated by a tilt mechanism to focus on a plurality of subjects.

[0002]

2. Description of the Related Art As a camera capable of focusing on a plurality of subjects, a system in which a tilt mechanism is built in an interchangeable lens of a 35 mm single-lens reflex camera is known. In addition, many large cameras equipped with a tilt mechanism for tilting a lens or a film have been commercialized. These tilt mechanisms are all based on manual operation, and require the skill of the photographer to focus on a plurality of subjects.

There is also known an auto-focus (AF) camera that measures a distance at multiple points in order to bring a plurality of subjects into a substantially focused state without using a tilt mechanism. An example of this is a camera that adjusts the focus so that a plurality of subjects fall within the depth of field.
-52538). This type of method is to reduce the possibility of focusing failure by selecting one of a plurality of pieces of focusing information or by taking an average, and does not actively focus. .

Further, as described in Japanese Patent Application Laid-Open No. 2-79808, for example, distance measurement is performed on a plurality of objects having different object distances so as to automatically focus on the plurality of objects. A camera having a built-in automatic tilt mechanism that can tilt a film surface or a lens is known.

However, in this automatic tilting device,
A multipoint distance measurement sensor capable of measuring the distance of at least three or more points of the subject is required. Particularly, in a camera that obtains a subject image using an image sensor, for example, a video camera or an electronic still camera, a sensor for distance measurement is provided in addition to the image sensor, so that the structure of the device becomes complicated and is not suitable for miniaturization. There were drawbacks.

As a tilting apparatus which solves these problems, an automatic tilting apparatus of a TTL video system which drives a tilting mechanism so that a high-frequency component of a video signal output from an image sensor is maximized has been realized. Kaihei 4-1968
No. 78).

The following is a brief description of this conventional TTL video system tilting apparatus.

FIGS. 17 and 18 are diagrams for explaining Scheimpflug's law, which is the principle of tilt photographing.
Generally, if the photographing lens system 1 and the image sensor 2 are parallel,
When the subject 20 is expensive, the entire area of the subject 20 is not focused. In order to focus on the entire area, the intersection point P between the imaging surface of the imaging device 2 and the object surface should cross the main plane of the imaging lens system 1. This is the law called Scheimpflug's law. When the Scheimpflug's law is actually applied, the image sensor 2 is inclined with respect to a plane perpendicular to the optical axis as shown in FIG.
In some cases, the photographing lens system 1 is tilted as shown in FIG.

FIG. 19 is a configuration diagram showing a conventional automatic tilting apparatus. In FIG. 19, reference numeral 1 denotes a photographing lens system. The photographing lens system 1 includes optical lens groups 101, 102, and 104 and a diaphragm 103. 1
Reference numeral 04 denotes a rotating lens group, and tilting correction is performed by rotating the rotating lens group 104. Reference numeral 2 denotes an image sensor, which converts a subject image obtained by the optical system into an electric image signal. Reference numeral 3 denotes a signal processing circuit that performs processing such as amplification, and reference numeral 4 denotes a high-frequency component extraction circuit that extracts a high-frequency component from an image signal. Reference numeral 6 denotes a control signal generation circuit for driving and controlling the tilt motor. Reference numeral 8 denotes a tilt motor drive circuit. Reference numeral 12 denotes a tilt motor constituted by a stepping motor, an ultrasonic motor, or the like, 13 denotes a motor gear attached to the tilt motor 12 and rotates integrally with the motor, and 14 denotes a rotating lens frame which rotates the motor gear 13 to be described later. 15 is a transmission gear.
Reference numeral 15 denotes a rotating lens group 104, and the rotating lens group 10
4 is a rotating lens frame that rotates integrally with the lens frame 4.

In a state where the main plane of the photographing lens system 1 and the image pickup surface of the image pickup device 2 are parallel, that is, in a state where the tilt correction is not performed, if the object is oblique, the image formation plane of the object and the image pickup The imaging surface of the element 2 does not overlap over the entire surface, and the entire area of the subject is not focused. Since the image of the subject in the out-of-focus portion is taken out of focus, the high-frequency component of the video signal is reduced.

Therefore, the rotation lens group 104 is minutely rotated, and the tilting mechanism is controlled based on the polarity and magnitude of the amount of change of the output signal of the high frequency component extraction circuit 4 which changes due to the minute rotation. By controlling the driving of the rotating lens group 104 so that the high-frequency component of the output signal of the image sensor 2 is maximized, tilt correction can be performed.

[0012]

However, the conventional automatic tilting apparatus has the following problems. This problem will be described with reference to FIGS. 20, 21, and 22.

20, 21 and 22, reference numeral 21 denotes an object plane, 22 denotes a main plane of a photographing lens system, 23 denotes an image pickup surface of an image pickup device, and 24 denotes an optically determined image by the photographing lens system and the image pickup surface 23. Reference numeral 25 denotes an object-side focus plane (hereinafter, referred to as an object plane), on which an object plane is formed by a photographing lens system.

FIG. 20 shows a state in which the tilt correction is not performed. In this state, since the subject image at the intersection M between the subject plane 21 and the object plane 24 is formed at the intersection M ′ between the imaging plane 23 and the imaging plane 25, a focus state occurs.
The subject image located on 1 is out of focus.

Therefore, in the conventional automatic tilting apparatus, as shown by an arrow in FIG. 21, the image pickup surface 23 is tilted so that the image pickup surface 23 coincides with the image forming surface 25.
The entire area of the object plane 21 is in focus.

However, in this case, the imaging plane 23 and the imaging plane 2
It is necessary to incline the imaging surface 23 around the intersection M ′ of 5 as the center of rotation. In other words, before the tilt correction, the subject image must be formed at the center of rotation when the imaging surface 23 is tilted. However, in the tilt mechanism, in order to be able to arbitrarily set the center of rotation when the imaging surface 23 is tilted, the mechanism becomes very complicated. That is, they are set on the optical axis.

Therefore, for example, as shown in FIG.
If there is no subject image at the center of rotation O when tilting 3, in other words, if there is no subject at the object point O ′ of the center of rotation O on the imaging surface 23, the automatic tilt correction cannot be performed. A similar problem occurs when the photographing lens system is tilted.

The present invention has been made under such a background. An object of the present invention is to provide a tilt mechanism for rotating an input medium for an optical image about a fixed center of rotation, by using an image pickup device obtained from an image sensor. When drive control is performed based on a signal to focus on a plurality of subjects, it is desirable to be able to reliably focus on a plurality of subjects having different subject distances without being affected by the positions of the subjects.

[0019]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an image pickup apparatus provided with a tilt mechanism for rotating an input medium for an optical image about a fixed center of rotation. First detection means for detecting focus information of a subject image from an image signal obtained from an image sensor at an infinite lens focus position, and detection of a local maximum value from focus information detected by the first detection means And a distance between a lens focus position corresponding to the plurality of local maxima when the plurality of local maxima are detected by the second detecting unit corresponding to a plurality of subjects having different subject distances. The first control that drives and controls the tilt mechanism so as to minimize
And second control means for controlling the driving of the tilt mechanism so that the maximum value becomes maximum.

According to the present invention, there is provided an image pickup method provided with a tilt mechanism for turning an input medium for an optical image about a fixed center of rotation. A first detection step of detecting focus information of a subject image from an image signal; and a second detection step of detecting a maximum value from the focus information detected in the first detection step.
Detecting step, and when a plurality of maxima are detected by the second detection step corresponding to a plurality of subjects having different subject distances, the distance between lens focus positions corresponding to the plurality of maxima is minimized. And a second control step of controlling the drive of the tilt mechanism so as to maximize the local maximum value.

According to the present invention, there is provided a storage medium storing a control program for focusing on a plurality of subjects by using a tilt mechanism for rotating an input medium for an optical image about a fixed center of rotation. And the control program includes:
A first detection routine for detecting focus information of a subject image from an image signal obtained from an image sensor for a lens focus position from a close to infinity, and a maximum value based on focus information detected by the first detection routine A second detection routine for detecting a plurality of maximum values detected by the second detection routine corresponding to a plurality of objects having different object distances, and a lens focus position corresponding to the plurality of maximum values. And a second control routine for controlling the drive of the tilt mechanism so that the maximum value is maximized.

In the present invention, the first detecting means,
The steps and routines detect a high-frequency component of the image signal as the focus information.

In the present invention, the first detecting means,
The steps and routines detect the sharpness of the edge shape of the image signal as the focus information.

In the present invention, the tilt mechanism is configured to rotate the input medium for the optical image about an optical axis around a rotation center.

In the present invention, the tilt mechanism is configured to rotate a part or the whole of a photographic lens system as an input medium for the optical image.

In the present invention, the tilt mechanism is configured to rotate the image sensor as an input medium for the optical image.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
It is a schematic structure figure of the imaging device with a tilt mechanism concerning the embodiment. In FIG. 1, reference numeral 1 denotes a photographing lens system. The photographing lens system 1 includes an optical lens group including 101, 102, and 104 and a diaphragm 103. Reference numeral 104 denotes a rotation lens group, and the rotation of the rotation lens group 4 performs a rear orientation correction. Reference numeral 2 denotes an image sensor, which converts a subject image obtained by the optical system into an electric image signal. Reference numeral 3 denotes a signal processing circuit for performing processing such as amplification.
Is a high frequency component extraction circuit for extracting high frequency components from the image signal. Reference numeral 5 denotes a maximum value detection circuit that detects a maximum value of a high frequency component.

Reference numeral 6 denotes a focus motor 9 and a tilt motor 12 which will be described later in order to perform a tilt correction unique to the present invention.
Is a control signal generating circuit for generating a control signal for controlling the driving of the control signal. The control signal generation circuit 6 is constituted by a microcomputer, and has a CPU 61, a ROM 62, and a RAM 63. A tilt correction program corresponding to the flowcharts of FIGS. 2 and 3 is preset in the ROM 62, and the CPU 61 performs tilt correction processing according to the tilt correction program while using the RAM 63 as a work area or the like.

Reference numeral 7 denotes a focus motor driving circuit,
Is a tilt motor drive circuit. Reference numeral 9 denotes a focus motor constituted by a stepping motor, an ultrasonic motor, or the like, 10 denotes a motor gear attached to the focus motor 9 and rotates integrally with the motor, and 11 denotes a transmission gear for transmitting rotation of the motor gear 10 to the photographing lens system 1. It is.
By driving the focus motor 9 to move the photographing lens system 1 back and forth on the optical axis, normal focus adjustment is performed.

Reference numeral 12 denotes a tilt motor constituted by a stepping motor, an ultrasonic motor or the like, 13 denotes a motor gear attached to the tilt motor 12 and rotates integrally with the motor, and 14 denotes a rotating lens frame for rotating the motor gear 13 to be described later. 15 is a transmission gear. Reference numeral 15 denotes a rotating lens frame which holds the rotating lens group 104 and rotates integrally with the rotating lens group 104. Tilt motor 12
To rotate the rotating lens frame 15 and the rotating lens group 104.
Is rotated to tilt the main plane of the rotation lens group 104 with respect to a plane perpendicular to the optical axis, thereby performing tilt correction. The center of rotation of the rotating lens group 104 is set on the optical axis (please let us know if it is correct).

Next, the tilt correction operation in the first embodiment will be described with reference to FIGS.

First, the CPU 61 of the control signal generating circuit 6 rotates the rotating lens group 104 so that the photographing lens system 1 and the image sensor 2 are in a parallel state, that is, a state in which the tilt correction is not performed. (Step S20 in FIG. 2)
1). Then, the local maximum value detection operation shown in detail in FIG. 3 is performed (step S202). That is, the CPU 61 first moves the photographing lens system 1 to the closest lens focus position by the focus motor 9 in order to sequentially scan the photographing lens system 1 from a close position to an infinity lens focus position (step S301 in FIG. 3). ). At this time, the image sensor 2
Outputs an image signal at the lens focus position,
Since the image signal is input to the high-frequency component extraction circuit 4 via the signal processing circuit 3, the CPU 61 causes the high-frequency component extraction circuit 4 to extract a high-frequency component of the image signal as focus information (step S1). S302).

Next, the photographing lens system 1 is slightly moved in the direction of the lens focus position at infinity (step S303).
High-frequency component detection processing similar to that in step S302 is performed (step S304). Then, it is determined whether or not the current position of the photographing lens system 1 is at the lens focus position at infinity (step S305). If not, the process returns to step S303 and the same processing is performed. repeat. On the other hand, if the lens focus position is at infinity,
As described above, the local maximum value detection circuit 5 detects the local maximum value from the high frequency components of the image signal obtained by sequentially scanning the photographing lens system 1 from the closest position to the lens focus position at infinity (step S306). .

Incidentally, the high frequency component of the image signal increases near the focus. Therefore, as shown in FIG. 4, when a plurality of subjects A, B, and C having different subject distances exist in the field, the high-frequency components extracted by the high-frequency component extraction circuit 4 are as shown in FIG. . In FIG. 5, a indicates the focus position of the subject A in FIG. Similarly, b and c indicate the focus positions of the B and C subjects, respectively. Generally, when an object is present at a plurality of lens focus positions, a plurality of local maxima are detected as shown in FIG. 5, and in this case, the local maximal value detection circuit 5 corresponds to the local maximal value and the local maximal value. The lens focus position is output.

When a plurality of local maxima are detected (step S203 in FIG. 2), the control signal generation circuit 6
The CPU 61 outputs a control signal for driving the tilt motor 12 to the tilt motor drive circuit 8 and drives the tilt motor 120 to slightly rotate the rotation lens group 104 (step S204). Then, the maximum value detecting operation is performed again (step S20).
5) It is determined whether or not the distance between the lens focus positions corresponding to the plurality of local maximum values has become minimum (step S20).
6). As a result, if not the minimum, the process returns to step S204, and the same processing is repeated. On the other hand, when the interval between the lens focus positions corresponding to the plurality of local maximum values is minimized, the fine rotation of the rotary lens group 104 and the local maximum value detection operation are repeated again, and the size of the local maximum value becomes maximum this time. The rotation of the rotation lens group 104 is controlled so as to satisfy (steps S207 to S209).

Here, assuming that the lens is slightly rotated in the direction T in FIG. 4, the relationship between the high frequency component and the lens focus position is as shown in FIG.
It becomes as shown in. In FIG. 6, a ′, b ′, and c ′ indicate the lens focus positions of the subjects A, B, and C after the rotation lens group 104 has slightly rotated. In FIG. 6, since the rotation lens group 104 is slightly rotated in the tilt correction direction, the distance between the lens focus positions a ′, b ′, and c ′ is the same as the lens focus positions a, b, and b before tilt correction in FIG. It is smaller than the interval of c. Conversely, the intervals between the respective lens focus positions when the rotation lens group 104 rotates in the direction of T ′ in FIG. 2 are not shown, but the lens focus positions a, b, and It becomes wider than the interval of c. As described above, when the interval between the lens focus positions is widened when the rotating lens group 104 is rotated, steps S204 to S204 are performed.
In the processing loop of 206, the rotating direction is immediately reversed.

As described above, the minute rotation of the rotating lens group 104 and the operation of detecting the maximum value are repeated, and as shown in FIG. 7, one lens focus position at which the maximum value is obtained or a plurality of lens focus positions is obtained. At the point when the interval becomes the narrowest,
The rotation of the rotation lens group 104 is repeatedly performed by repeating the minute rotation of the rotation lens group 104 and the maximum value detection operation, and this time, the rotation of the rotation lens group 104 is controlled so that the maximum value becomes maximum.

Then, as shown in FIG. 8, when the maximum value reaches the maximum, the rotation of the rotation lens group 104 is stopped. Next, the focus motor 9 is driven in this state,
The photographing lens system 1 is moved to the lens focus position x where the maximum value Vmax is obtained (step S210), and the tilt correction ends. By performing the photographing operation in the state where the tilt correction has been performed in this manner, image signals that are in focus on a plurality of subjects having different subject distances can be obtained.

Next, a case where the subject is uniformly present on a plane where the subject distance changes linearly, such as a character written on paper or the like, will be described with reference to FIGS. I do.

In FIG. 9, reference numeral 20 denotes a subject which exists uniformly on a plane where the subject distance linearly changes. When such a subject 20 is photographed, the high-frequency component of the image signal when the photographing lens system 1 is sequentially scanned from a close position to an infinity lens focus position without performing the tilt correction, as shown in FIG. Is uniform in the range of m to n where one exists, and one local maximum value is detected.

As in this case, step S20 in FIG.
If it is determined in step 3 that the number of local maxima is one, the rotation lens group 104 is moved so that the interval between the lens focus positions corresponding to the plural local maxima in steps S204 to S206 is minimized. The rotation process is skipped, and the processes of steps S207 to S209, that is, the micro-rotation and the maximum value detection operation of the rotation lens group 104 are repeated, and the rotation lens group is set so that the maximum value becomes maximum. 1
04 is controlled. Then, when the maximum value reaches the maximum, the rotation of the rotation lens group 104 is stopped, and the focus motor 9 is driven to drive the maximum maximum value Vma.
The photographing lens system 1 is moved to the lens focus position x where x was obtained (step S210), and the tilt correction is completed.
Also in this case, an in-focus image signal can be obtained in all regions of the subject 20.

[Second Embodiment] FIG. 11 is a schematic configuration diagram of an image pickup apparatus with a tilt mechanism according to a second embodiment of the present invention. In FIG. 11, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 11, reference numeral 1 denotes a photographing lens system. The photographing lens system 1 includes an optical lens group of 101, 102, and 105 and a stop of 103. 1
Reference numeral 7 denotes a transmission gear for transmitting the rotation of the tilt motor 12 to an image pickup device rotation frame 18 described later via the motor gear 13. Reference numeral 18 denotes an image sensor rotation frame that rotates integrally with the image sensor 2.

In the present embodiment, the tilt correction is performed by rotating the image sensor 2 instead of rotating the lens as in the first embodiment. The control operation for tilt correction is exactly the same as in the first embodiment. Note that the center of rotation of the image sensor 2 is set on the optical axis.

When the image pickup device 2 is rotated as in this embodiment, since the image pickup device 2 is lighter in weight than the optical system, a small and light motor can be used as the tilt motor 12. This is advantageous for reducing the size and weight of the entire apparatus. Further, an optical system having no tilt correction function can be used as it is, and lens replacement becomes easy.

[Third and Fourth Embodiments] In the first and second embodiments, the high-frequency component of the image signal is used as the focus information of the subject image.
Any information may be used as long as the information has a local maximum value or a local minimum value at the subject position. For example, information on the edge shape of the image signal may be used. So, third,
In the fourth embodiment, information on the edge shape of an image signal is used as focus information.

FIGS. 12 and 13 are schematic structural views of an image pickup apparatus with a tilt mechanism according to the third and fourth embodiments, respectively. As the mechanical tilt mechanism in the third embodiment of FIG. The lens is configured to rotate in the same manner as in the first embodiment, and the mechanical tilt mechanism in the fourth embodiment in FIG. 13 is configured to rotate the image sensor 2 in the same manner as in the second embodiment. It is configured as follows. In addition,
The center of rotation of each of these tilt mechanisms is set on the optical axis.

As an electrical configuration for performing the tilt correction, in both of the third and fourth embodiments, as shown in FIGS. 12 and 13, the first and second embodiments are shown. Is provided with an ES filter 19 for obtaining an ES value indicating the sharpness of the edge of the image signal.

The focus information detection method (ES method) using the information of the edge shape is disclosed in US Pat. No. 4,804,831 and will be described only briefly. FIG. 14 is a diagram illustrating a configuration example of the ES filter 19. In FIG. 14, 31
Is a differentiation circuit, 32 is an absolute value circuit, 33 is a delay circuit, 34
Is an integration circuit, and 35 is a division circuit. The integration circuit 34
Two delay circuits 34a and 34b and one adder circuit 34c
It consists of.

Next, the function of the ES filter 19 shown in FIG. 14 will be described with reference to the waveform diagram of FIG.

FIG. 15A is a waveform diagram of an image signal, and the edge of the image signal has a steep slope when focused.
When out of focus, the slope is gentle. FIG.
FIG. 6 is a differential waveform diagram obtained by differentiating the image signal of FIG. FIGS. 15C and 15D respectively show:
FIG. 16B is a waveform diagram obtained by delaying the differential waveform of FIG. 15B (strictly, a signal whose polarity is unified to be positive by the absolute value circuit 32) by the delay circuits 33 and 34a and the delay circuit 34b. FIG. 15E shows FIGS. 15B, 15C, and 15C.
FIG. 6 is an integrated waveform diagram obtained by integrating the waveform of (d) by an integration circuit 34, and this integrated waveform represents a contrast of an edge portion of an image signal.

FIG. 15 (f) shows a waveform obtained by dividing the differential waveform of FIG. 15 (b) by the integral waveform of FIG. 15 (e) by the dividing circuit 35. The division value is output as an ES value indicating the sharpness of the edge. This ES method is characterized in that it is not affected by the size, contrast, and illumination of the subject.

FIG. 16 is a diagram showing changes in the lens position and the ES value when performing the AF operation for obtaining the in-focus position. The lens is fed continuously from a minimum position (closest position) to a maximum position (infinity), during which an image signal is stored in the image sensor 2 every one vertical scanning period and the image signal is read out.
The ES value is obtained from the image signal by the ES filter 19, and the position having the largest ES value is detected by the local maximum value detection circuit 5 and detected as the focus position, that is, the local maximum value.

A curve having a peak at the in-focus position drawn when the lens feed amount is plotted on the horizontal axis and the focusing signal (in this case, the ES value) is plotted on the vertical axis is called a hill-climbing curve. It is characterized by its steepness and good focus detection accuracy.

The present invention is not limited to the above-described embodiment, and may be applied to, for example, a tilt mechanism for rotating the entire photographic lens system without rotating a part of the photographic lens system. Is also possible.

[0057]

As described above, according to the present invention,
In an imaging apparatus having a tilt mechanism for rotating an input medium of an optical image about a fixed rotation center, focusing information of a subject image is obtained from an image signal obtained from an imaging device with respect to a close-to-infinite lens focus position. Detecting means for detecting a maximum value from focus information detected by the first detecting means, and a second detecting means for detecting a plurality of objects having different object distances. A first control means for driving and controlling the tilt mechanism so that a distance between lens focus positions corresponding to the plurality of maximum values is minimized when a plurality of maximum values are detected by the detection means; A second control means for driving and controlling the tilt mechanism so as to maximize the value, so that a tilt mechanism for rotating the input medium of the optical image about a fixed rotation center is obtained from the image sensor. Be When driven controlled based on the image signal focused on the plurality of subjects, without being affected by the position of the subject, it is possible make reliable focus for different plurality of subjects of the subject distance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an imaging device with a tilt mechanism according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a tilt correction process according to first to fourth embodiments of the present invention.

FIG. 3 is a flowchart showing details of a maximum value detection process in FIG. 2;

FIG. 4 is a diagram illustrating a first subject example.

5 is a diagram illustrating a relationship between a high-frequency component of an image signal before tilt correction and a lens focus position corresponding to the example of a subject in FIG. 4;

6 is a diagram illustrating a relationship example between a high-frequency component of an image signal after a first stage tilt correction process and a lens focus position corresponding to the subject example in FIG. 4;

7 is a diagram illustrating another example of the relationship between the high-frequency component of the image signal after the first stage tilt correction process and the lens focus position corresponding to the example of the subject in FIG. 4;

FIG. 8 is a diagram illustrating another example of the relationship between the high-frequency component of the image signal after the tilt correction processing in the second stage and the lens focus position.

FIG. 9 is a diagram illustrating a second example of a subject;

10 is a diagram illustrating a relationship example between a high-frequency component of an image signal after a first-stage tilt correction process and a lens focus position corresponding to the second subject example in FIG. 9;

FIG. 11 is a schematic configuration diagram of an imaging device with a tilt mechanism according to a second embodiment of the present invention.

FIG. 12 is a schematic configuration diagram of an imaging device with a tilt mechanism according to a third embodiment of the present invention.

FIG. 13 is a schematic configuration diagram of an imaging device with a tilt mechanism according to a fourth embodiment of the present invention.

FIG. 14 is a block diagram illustrating a configuration of an ES filter in FIGS. 12 and 13;

FIG. 15 is a diagram showing signal waveforms at various parts of the ES filter of FIG. 14;

FIG. 16 is a diagram showing a hill-climbing curve in the ES method.

FIG. 17 is a diagram illustrating Scheimpflug's law when the image sensor is tilted.

FIG. 18 is a diagram illustrating Scheimpflug's law when the taking lens system is tilted.

FIG. 19 is a view showing a schematic configuration of a conventional TTL automatic tilting apparatus.

FIG. 20 is a view for explaining a problem of a conventional TTL automatic tilt apparatus.

FIG. 21 is a view for explaining a problem of a conventional TTL automatic tilt apparatus.

FIG. 22 is a diagram for explaining a problem of a conventional TTL automatic tilt apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photographing lens system 2 imaging element 4 high-frequency component extraction circuit 5 maximum value detection circuit 6 control signal generation circuit 12 tilt motor 13 motor gears 14 and 17 transmission gear 19 ES filter 61 CPU 62 ROM 63 ... RAM 104 ... Rotating lens group

Claims (18)

[Claims] An image pickup apparatus provided with a tilt mechanism for rotating an input medium for an optical image about a fixed center of rotation, wherein an object is obtained from an image signal obtained from an image pickup element at a lens focus position from a close to infinity. First detecting means for detecting focus information of an image, second detecting means for detecting a local maximum value from the focus information detected by the first detecting means, corresponding to a plurality of subjects having different subject distances Then, when a plurality of local maxima are detected by the second detecting means, a first control for driving and controlling the tilt mechanism so that an interval between lens focus positions corresponding to the plural maximal values is minimized. Means for controlling the tilt mechanism so as to maximize the local maximum value. 2. The imaging apparatus according to claim 1, wherein the first detection unit detects a high-frequency component of the image signal as the focus information. 3. The imaging apparatus according to claim 1, wherein the first detection unit detects sharpness of an edge shape of the image signal as the focus information. 4. The imaging apparatus according to claim 1, wherein the tilt mechanism is configured to rotate the input medium of the optical image about an optical axis about a rotation center. 5. The imaging apparatus according to claim 1, wherein the tilt mechanism is configured to rotate a part or all of a photographic lens system as an input medium for the optical image. 6. The image pickup apparatus according to claim 1, wherein the tilt mechanism is configured to rotate the image pickup device as an input medium for the optical image. 7. An imaging method comprising a tilt mechanism for rotating an input medium for an optical image about a fixed rotation center, wherein a subject is obtained from an image signal obtained from an imaging device for a lens focus position from a close to infinity. A first detection step of detecting focus information of an image, a second detection step of detecting a local maximum value from the focus information detected by the first detection step, and corresponding to a plurality of subjects having different subject distances Then, when a plurality of local maximum values are detected in the second detecting step, a first control for driving and controlling the tilt mechanism such that an interval between lens focus positions corresponding to the plural local maximum values is minimized. And a second control step of controlling the drive of the tilt mechanism so that the local maximum value is maximized. 8. The imaging method according to claim 7, wherein the first detection step detects a high-frequency component of the image signal as the focus information. 9. The imaging method according to claim 7, wherein the first detection step detects sharpness of an edge shape of the image signal as the focus information. 10. The imaging method according to claim 7, wherein the tilt mechanism is configured to rotate the input medium of the optical image about an optical axis around a rotation center. 11. The imaging method according to claim 7, wherein the tilt mechanism is configured to rotate a part or all of a photographic lens system as an input medium for the optical image. 12. The imaging method according to claim 7, wherein the tilt mechanism is configured to rotate the image sensor as an input medium for the optical image. 13. A storage medium storing a control program for focusing on a plurality of subjects by using a tilt mechanism for rotating an input medium for an optical image about a fixed center of rotation, wherein The control program includes: a first detection routine for detecting focus information of a subject image from an image signal obtained from an image sensor with respect to a lens focus position from a close to infinity; and a focus detected by the first detection routine. A second detection routine for detecting a maximum value from the information, and a plurality of maximum values detected by the second detection routine corresponding to a plurality of objects having different object distances.
A first control routine for controlling the drive of the tilt mechanism so as to minimize the distance between the lens focus positions corresponding to the plurality of local maximum values; and a drive control for controlling the drive of the tilt mechanism so as to maximize the local maximum value. 2. A storage medium, comprising: a control routine according to claim 2; 14. The storage medium according to claim 13, wherein the first detection routine detects a high-frequency component of the image signal as the focus information. 15. The storage medium according to claim 13, wherein said first detection routine detects sharpness of an edge shape of said image signal as said focus information. 16. The storage medium according to claim 13, wherein the tilt mechanism is configured to rotate the input medium for the optical image about an optical axis about a rotation center. 17. The storage medium according to claim 13, wherein the tilt mechanism is configured to rotate a part or all of a photographic lens system as an input medium for the optical image. 18. The storage medium according to claim 13, wherein the tilt mechanism is configured to rotate the image sensor as an input medium for the optical image.