JP2002325199A - Electronic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic imaging device provided with a swing adjustment function that can correct distortion of an image resulting from photographing a large-sized object at a position with an offset from a front of the object in photographing the large sized object such as a high rise building. SOLUTION: The electronic imaging device 10 includes an optical image forming means 12 that forms an object image included in a photographing visual field and an electronic image pickup means 13 that is pressed into contact with a plane on which the image is formed and uses an image pickup device to convert the spatial luminous quantity on the plane into an electric signal. The focal position is adjusted by displacing the optical system of the optical image forming means 12 in the direction of the optical axis of the optical image forming means 12, the image pickup face 11 of the electronic image pickup means 13 is supported in a tilted way around an axis perpendicular to the optical axis 14, and the image pickup face 11 is adjusted to have an optional tilt angle so as to obtain a well-focused image of the object 1 even from a plane tilted from the perpendicular plane to the optical axis 14.

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 apparatus, and more particularly, to an electronic image pickup apparatus such as a digital camera and a digital video camera. The present invention can be applied to a camera in which such shooting conditions are regulated, and is suitable for a camera with a tilt function for obtaining a large omnidirectional image such as a side of a building.

[0002]

2. Description of the Related Art Conventionally, when photographing a high-rise building or the like, the photographing is performed from a position shifted from the front of the subject, but the distance to the subject is extremely different within one screen. In this case, it is not possible to obtain a photograph in which the entire subject is in focus unless the aperture is stopped down.

FIG. 17 is a diagram showing an example of the configuration of a conventional photographing apparatus. In the figure, reference numeral 1 denotes a subject, 1a denotes a farthest contact, 1b
Is the closest point, and 40 is a photographing device.
Has a lens 41 and an imaging surface (film surface) 42. A camera with a tilting function for rotating an imaging surface as shown in FIG. 18 about an axis perpendicular to the optical axis in order to shoot the above scene is well known. FIG.
8 is a diagram illustrating a configuration example of a photographing device 40 with a tilt function. The photographing device 40 with a tilt function has a lens 41, an imaging surface (film surface) 42, and an optical axis 43.
Of the film surface 42 and a tilt function of freely changing the inclination of the film surface 42.

[0004] By adopting the above-described apparatus configuration, it is possible to obtain a photograph in which the whole scene is in focus even in the above-described scene. Photographing device 40 with such tilt function
Is mainly used for professional use, and is usually adjusted manually. Here, with a silver halide camera, it is difficult to incline only the film surface from the point of view of mechanism and light shielding.
A method of tilting the optical axis of the lens has been adopted.

[0005] Further, for example, a similar application can be considered in an electronic imaging device such as a digital camera. In such an electronic imaging device, an imaging device such as a CCD is used. It is also possible to incline the imaging device as in the invention described in Japanese Patent Laid-Open No. H10-209, so that the tilt adjustment can be performed more easily.

In recent years, for example, digital cameras have been widely used in place of silver halide cameras. In a digital camera, photographed data is digital information, and thus, a use form that has never been seen before has been considered. One of the applications is to digitize characters, images, etc. on a plane like a scanner, but in such a usage form, rather than a scene that can be captured in front of the plane, a scene that is photographed obliquely from a position shifted from the front It is expected that there will be many. Therefore, it is considered that the tilt adjustment means as described above is effective. In this case, the obtained image is distorted, but since it is digital information, it can be corrected by image processing. Therefore, only the screen focus needs to be guaranteed for these uses.

With respect to the tilt mechanism of the electronic image pickup apparatus, according to the above-described image pickup apparatus described in Japanese Patent Application Laid-Open No. 9-331476, the tilt can be adjusted by electric power. However, it is preferable that not only special shooting but also amateurs be able to easily use scenes that the user actually shoots for the above-described purpose. Therefore, for these uses, an autofocus function is required. Normal auto focus is based on the premise that all imaging surfaces have the same focus, and the optimum focus position is determined by referring to the distance calculated from an external distance measuring device or the actual high frequency component of the CCD output. The adjustment is made by moving the optical system or the CCD in the direction of the optical axis.

However, when tilting occurs, the focusing axis must be adjusted not only in the optical axis but also in the tilting direction, and there has been a problem that the conventional autofocusing alone does not function.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an electronic imaging device with a tilt function having a focus mechanism capable of tilt adjustment. It was done.

More specifically, first, the optical system is displaced in the optical axis direction to adjust the focal position, and a tilt angle adjusting means in a tilt direction about an axis perpendicular to the optical axis direction is provided. Obtaining an in-focus image for a subject on a plane inclined from a plane perpendicular to the optical axis,

Second, for example, an image pickup device such as a CCD is displaced in an optical axis direction to adjust a focal position, and a tilt angle adjusting means in a tilt direction about an axis perpendicular to the optical axis direction is provided. With a simpler configuration, it is possible to obtain an in-focus image for a subject on a plane inclined from a plane perpendicular to the optical axis,

Thirdly, by controlling and adjusting the focal position by using a high-frequency component of an arbitrary image pickup area in the output of the image pickup device, it is possible to adjust the focus without providing an external device separately.

Fourthly, by providing an inclination axis for tilt adjustment on the imaging surface of the imaging element, the focal position in the optical axis direction is not shifted by the inclination angle adjusting means.

Fifth, in adjusting the focal position in the optical axis direction, only the high-frequency component near the tilt axis is used, so that the focus can be prevented from being out of focus by the tilt angle adjusting means.

Sixth, by using an imaging area set in a direction perpendicular to the tilt axis as tilt angle adjusting means, it is possible to perform more precise tilt adjustment.

Seventh, by calculating the amount of tilt of the imaging surface by measuring two or more in-focus positions within the imaging surface using only the focus adjustment mechanism, enabling high-speed operation.

Eighth, the accuracy of calculating the amount of tilt can be improved by taking two or more measurement points in the imaging plane in a direction perpendicular to the tilt axis.

Ninth, the control circuit is simplified by setting the maximum value of the high-frequency component as a control target in adjusting the focal position and the amount of tilt.

Tenth, speeding up the operation by adjusting the focal position by using an external distance measuring means for measuring the distance to the subject;

Eleventh, by making the measurement area of the distance measuring means coincide with the imaging area near the tilt axis in the tilt angle adjusting means, the focus is prevented from being shifted by the tilt angle adjusting means.

Twelfth, by using an imaging area set in a direction perpendicular to the tilt axis as tilt angle adjusting means,
To enable more precise tilt adjustment,

Thirteenth, in adjusting the focus position and the tilt amount, the control circuit is simplified by setting the maximum value of the high frequency component as a control target.

Fourteenth, the amount of tilt is calculated by measuring the distance to the subject at two or more places, so that operation can be performed at higher speed.

Fifteenth, the accuracy of correction can be improved by setting the measurement point of the distance to the subject in a direction perpendicular to the tilt axis.

Sixteenth, the objective is to easily obtain a front image by correcting the image distortion using the amount of tilt obtained from the control amount as a result of controlling the focus position and the amount of tilt as a parameter. Things.

[0026]

According to a first aspect of the present invention, there is provided an optical image forming means for forming an image of an object contained in a field of view on a plane, and an optical image forming means which abuts on the formed plane, and A focus position adjusting means for adjusting a focus position by displacing the optical imaging means, and an optical axis; A tilt angle adjusting means for holding the image pickup surface of the electronic image pickup means at least at least one axis so as to be tiltable about an axis perpendicular to the axis, and for adjusting the image pickup surface of the electronic image pickup means to an arbitrary tilt angle. It is characterized by the following.

According to a second aspect of the present invention, there is provided an optical image forming means for forming an object image contained in a field of view on a plane, and an image pickup device which comes into contact with the formed plane and measures the amount of spatial light in the plane. A focus position for adjusting a focus position by displacing an image pickup device of the electronic imaging means in an optical axis direction of the optical imaging means. Adjusting means for holding the imaging surface of the electronic imaging means so as to be tiltable about at least one axis about an axis perpendicular to the optical axis, and adjusting the imaging surface of the electronic imaging means to an arbitrary inclination angle; And adjusting means.

According to a third aspect of the present invention, in accordance with the first or second aspect of the present invention, the imaging area of the electronic imaging means is specified so that an electric signal of an arbitrary area converted by the electronic imaging means can be extracted as a video signal. An image pickup area specifying means for extracting, a frequency component extracting means for extracting an arbitrary frequency component in a video signal extracted from the specified image pickup area, a storage means for storing a value of the extracted frequency component, Comparing and judging the calculated frequency component and the frequency component stored immediately before, and operating the focus position adjusting means and the tilt angle adjusting means based on the judgment output of the comparing and judging means to control And control means for performing the control.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the tilt axis of the tilt angle adjusting means is provided on an imaging surface of the electronic imaging means.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, an imaging area which is coincident with or close to the tilt axis is set as an evaluation area, and only an output of a video signal in the evaluation area is set as an evaluation value. Focus adjustment is performed by the focus position adjusting means based on the evaluation value, and an imaging area different from the evaluation area is used for the operation of the tilt angle adjusting means.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the output of video signals in at least two or more imaging areas at different positions perpendicular to the tilt axis is used as an evaluation value, and The tilt angle of the imaging surface is adjusted based on the angle.

According to a seventh aspect of the present invention, in any one of the first to third aspects, when the imaging surface of the electronic imaging means is at a fixed angle with respect to an optical axis, the focus position adjusting means is provided. By operating, there are provided a focus position specifying means for specifying a focus position of at least two or more image pickup areas in the image pickup surface, and a storage means for storing the specified focus position. The tilt amount of the imaging surface is determined based on the focused position.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the output of the video signal in at least two or more imaging areas at different positions perpendicular to the tilt axis is used as an evaluation value, and The amount of inclination of the image pickup surface is obtained based on the image.

According to a ninth aspect of the present invention, in the invention of the sixth or eighth aspect, a high-frequency component in an imaging area is used as the evaluation value, and a maximum point of the high-frequency component is determined by an inclination amount of the imaging surface and a focus position. This is characterized in that it is set as a control target.

According to a tenth aspect of the present invention, in accordance with the first or second aspect of the present invention, there is provided a distance measuring means for measuring a distance to a subject, and the focal position adjusting means based on a value measured by the distance measuring means. And an image pickup area specifying means for specifying an image pickup area of the electronic image pickup means so that the electric signal converted by the electronic image pickup means can be picked up as a video signal; and a video signal picked up from the specified image pickup area. Frequency component extracting means for extracting an arbitrary frequency component, storage means for storing the value of the extracted frequency component, and determination by comparing the extracted frequency component with the frequency component stored immediately before Control means for operating and controlling the focus position adjusting means and the tilt angle adjusting means based on the judgment output of the comparing and judging means; It is obtained by characterized by comprising.

According to an eleventh aspect of the present invention, in the tenth aspect, the measurement area of the distance measuring means corresponds to an imaging area on or near a tilt axis of an imaging surface of the electronic imaging means. It is what it was.

According to a twelfth aspect of the present invention, in the tenth aspect of the present invention, the output of the video signal in at least two or more imaging areas at different positions perpendicular to the tilt axis is used as an evaluation value, and The tilt angle of the imaging surface is adjusted based on the angle.

According to a thirteenth aspect, in the twelfth aspect, a high-frequency component in an imaging area is used as the evaluation value, and a maximum point of the high-frequency component is set as a control target of the tilt amount of the imaging surface. It is a characteristic.

According to a fourteenth aspect of the present invention, in the first or the second aspect of the present invention, a distance measuring means for measuring a distance to a subject, and a changing means capable of selectively changing a measuring position of the distance measuring means within a field of view. And storage means for storing the distance to the subject at at least two or more measurement points in the field of view, wherein the focus position adjusting means and the tilt angle adjusting means are based on the measured distance to the subject. Is operated and controlled.

According to a fifteenth aspect, in the fourteenth aspect, at least two or more imaging areas are provided at different positions perpendicular to the tilt axis.

The invention of claim 16 is the invention of claims 1 to 15
Any one of the inventions, further comprising a tilt amount calculating means for calculating a tilt amount from the tilt control amount controlled by the tilt angle adjusting means, and a light amount of the optical imaging means based on the obtained tilt amount. An angle formed between the axis and the normal direction of the object plane is obtained, and distortion of an image output from the electronic imaging means is arithmetically corrected based on the angle.

[0042]

(Embodiment 1) FIG. 1 is a diagram showing a configuration example of an electronic imaging apparatus to which the present invention is applied.
Denotes an electronic imaging device, which includes a CCD imaging surface 11, an optical focus adjustment mechanism 12, a CCD tilt mechanism 1
3. a camera optical axis 14; The subject 1 is formed of a two-dimensional plane as shown in the drawing, and the camera optical axis 14 is greatly inclined from the vertical axis of the drawing. In such photographing, the difference in the distance between the farthest contact point 1a and the closest contact point 1b to the subject cannot be ignored in close-up with the camera closer, and the image becomes blurred in the tilt direction.

First, since the focus position changes depending on the distance to the subject, the optical focus adjustment mechanism 12 for moving the focus position by adjusting the optical system in the direction of the optical axis is adjusted. Focus the point.
Next, by adjusting the CCD tilt mechanism 13, the relative distance between the optical system and the CCD with respect to the subject 1 is changed, so that an image in which the subject 1 as shown in FIG. Is obtained. Here, for simplicity, 1
Although the description has been given of the tilt adjustment of the shaft, the same adjustment can be performed in the case of two shafts.

FIG. 2 is a view showing an example of the structure of a CCD tilt mechanism 13 to which the present invention is applied.
CD imaging surface 11, tilt axis 15, rotation actuator 1
6. The CCD imaging surface 11 is attached so as to be rotatable about a tilt axis 15, and the tilt amount is controlled by a rotation actuator 16. In this example, the tilt axis 15 is located substantially in the middle of the CCD imaging surface 11, but may be located at a position other than the center depending on the stroke of the actuator to be used and the peripheral space. However, it is desirable that the tilt axis 15 and the optical axis 14 be perpendicular to each other in order to ensure the independence of adjustment. Here, for the sake of simplicity, a description is given of the tilt adjustment of one axis. However, the same adjustment is possible in the case of two axes. Further, as the rotation actuator 16, a rotation actuator that directly gives rotation about the tilt axis 15 as well as going straight may be used.

(Embodiment 2) FIG. 3 is a diagram showing another example of the configuration of an electronic imaging apparatus 10 to which the present invention is applied. FIG.
FIG. 2 is a view showing another example of the configuration of the CCD tilt mechanism 13 to which the present invention is applied.
1, an inclination shaft 15, a rotation actuator 16, and a translation actuator 17. The device configuration of the electronic imaging device 10 in this example is different from the device configuration shown in FIG. 1, but has the same effect. The CCD imaging surface 11 is mounted to be tiltable by a tilt shaft 15, and is driven and controlled by a rotation actuator 16, similarly to the above device configuration. Similarly, it is translated by the translation actuator 17 in the optical axis direction. First, the CCD imaging surface 11 is translated by the translation actuator 17 in the optical axis direction, and an arbitrary position is focused.
Next, the CCD imaging surface 1 is rotated by the rotation actuator 16.
1 is tilted to obtain an image in which the entire object is in focus. Here, the translation and rotation actuators are separate for the purpose of explanation, but they may be combined into one actuator that can provide translation and rotation. Although not shown, a movement guide is provided so that the posture other than the tilt axis does not change significantly during the adjustment movement, so that movement other than translation and rotation is restricted.

FIG. 5 is a block diagram showing an example of the internal configuration of the control unit of the electronic imaging apparatus 10 to which the present invention is applied.
Reference numeral 20 denotes a control unit. The control unit 20 includes a CCD 21, a frame memory 22, a high-frequency component extractor 23, an adder 24,
It has a memory 25, a CPU 26, and an optical system 27. CC
The video signal captured from D21 is stored in the frame memory 2
2 As for the image data on the frame memory 22, the image data included in an arbitrary imaging area can be read by specifying an address from the CPU 26. C
After the image data of the designated imaging area is read from the PU 26, the high frequency component is extracted by the high frequency component extractor (filter) 23. Here, a high frequency component is extracted, but a component in an arbitrary frequency band may be used. Also,
It is conceivable to simultaneously extract components of two or more frequency bands. In this case, the following configuration requires two or more systems.

The high-frequency data extracted as described above is added to the image data in the imaging area by the adder 24 or the like, and is used as a high-frequency evaluation value indicating the imaging area. In this example, the configuration using the filter 23 and the adder 24 is shown. However, for example, a frequency spectrum of an arbitrary imaging area such as DCT may be obtained, and the high frequency component thereof may be directly obtained. Also in this case, it is conceivable that two or more frequencies are obtained and used as evaluation values. These evaluation values are read directly into the CPU 26 and used for evaluation of focus determination. Based on this evaluation value determination, the CPU 26
D21 and an actuator for tilt adjustment and focus adjustment attached to the optical system 27 are controlled.

As shown in FIG. 2 and FIG.
The tilting mechanism 13 first adjusts the focus by adjusting the optical system or the CCD by moving the CCD back and forth.
Adjust the tilt direction. At this time, the rotary tilt shaft 15
Are arranged so as to coincide with each other on the CCD imaging surface 11, and eliminate the defocus by preventing the position in the optical axis direction near the tilt axis 15 from being shifted by the tilt rotation operation.

FIG. 6 is a diagram showing a configuration example of a CCD imaging surface 11 to which the present invention is applied. The CCD imaging surface 11 has imaging areas 11a, 11b, 11c, and a tilt axis 15.
FIG. 6 corresponds to a view of the CCD imaging surface 11 viewed from the optical axis direction. The tilt axis 15 is on the CCD imaging surface 11. First, focus adjustment is performed, and the imaging area 11a near the tilt axis 15 is used as an evaluation area for focus adjustment. Based on the evaluation value obtained from the imaging area 11a, the above-described translation actuator 17 or the optical focus adjustment mechanism 12 is controlled, and after it is determined that the imaging area is in focus, the rotation axis of the rotation actuator 16 is separately provided. 1
A rotation of the CCD imaging surface 11 about 5 is given.
As the evaluation value used for the tilt control, an evaluation value of the imaging area 11b or 11c at a position separated in the direction orthogonal to the tilt axis 15 is used separately from the imaging area 11a, and based on the evaluation value, the rotation actuator 16 is used. Is controlled.
With such a configuration, the focus adjustment and the tilt adjustment are kept independent. In this example, an example in which the focus adjustment and the tilt adjustment are performed in a time-series manner has been described.

FIGS. 7 and 9 are diagrams showing an operation example of the CCD imaging surface 11. As shown in FIG.
Is moved by the translation actuator 17 while the rotation about the tilt axis 15 is fixed. In this case, if the tilt has occurred, the position of the focal point in each imaging area of the CCD imaging surface 11 will be different. In this example, the in-focus positions are from P1 to P3.

FIG. 8 is a diagram showing a change in a high frequency component at an arbitrary position on the CCD image pickup surface 11. FIG. 7 is a graph showing changes in high frequency components when the movement shown in FIG. 7 is given. The high frequency components are plotted on the vertical axis, and the CCD position is plotted on the horizontal axis.
The peaks of the high-frequency evaluation values corresponding to the focus positions P1, P2, and P3 are shown. These in-focus positions are temporarily stored separately in a memory (not shown), and the focal positions as shown in FIG. 9 are determined from the geometrical positions on the CCD imaging surface 11 in the imaging area and these in-focus positions (P1 to P3). And the amount of inclination are calculated, and the amount of movement and the amount of inclination in the optical axis direction are determined. In the description so far, the focus position scan is performed by moving the CCD imaging surface 11 in the optical axis direction.
The moving amount of the imaging surface 11 may be calculated, and the control amount of the optical focusing unit and the inclination amount of the CCD imaging surface 11 may be calculated.

FIG. 10 shows the high frequency components of the video signal and the CCD.
It is a figure showing an example of a relation of a position. When the same subject is photographed in the same imaging area, the output of the high-frequency component becomes highest when the video signal is focused. Therefore, when the focus is adjusted, the peak of the high-frequency evaluation value in an arbitrary imaging area indicates the in-focus position.

FIG. 11 is a flowchart for explaining an example of an algorithm for obtaining the peak of the high frequency component. First, a high-frequency evaluation value is obtained using the high-frequency component extractor 23 and the adder 24 as shown in FIG.
1). Next, this evaluation value is read into the CPU 26 and compared with the high-frequency evaluation value one step before (step S).
2). If the evaluation value is not a peak (NO),
The evaluation value is stored in the memory 25 (step S3).
Next, the focal position / inclination amount is adjusted based on the evaluation value (step S4). When the evaluation value is at the peak (in the case of YES), the control is completed. Here, the peak can be determined by a change such that the difference from the previous evaluation value disappears, or falls within a certain range, or the increase is reversed to decrease. Further, even when it is determined that the evaluation value is not the peak, the direction to the in-focus position can be determined by increasing or decreasing the evaluation value one step before. In this case, the evaluation value is temporarily stored in the memory 25, and is used as data of the previous step in the next evaluation.

In the case of focus adjustment, the focus position is further advanced in the detection direction by one step, and in the case of tilt adjustment, the tilt amount is set to 1
Step forward and obtain the next high-frequency evaluation value. If it is determined to be a peak, it is determined to be a control completion point, and a series of operations is completed. In this example, only one system is used for the high-frequency evaluation value, but the high-frequency component has a steep peak and can be controlled with high accuracy, but the control direction tends to be unclear when the distance from the in-focus position is low. Focusing accuracy is not good with the component, but the direction can be understood even if the distance is large, so a method using two or more frequencies, such as finding the direction of the approximate focus position at a low frequency and finding the focus position at a further high frequency Is also conceivable.

(Embodiment 3) FIG. 12 is a diagram showing another example of the configuration of an apparatus using a distance measuring means using infrared rays.
0 is an infrared LED (light emitting element), 31 is a subject, 32
Is a PSD (light receiving element). In the apparatus configuration of this example, the inventor obtained the in-focus position in the optical axis direction by the optical focus adjustment mechanism 12 and the movement adjustment mechanism in the optical axis direction of the CCD imaging surface 11, whereas the external It is characterized in that a distance measuring means is used. The infrared light emitted from the infrared LED 30 is reflected by the subject 31 and received by the PSD 32. PSD
32, the position where the light is received on the PSD 32 is obtained, and the incident angle β of the infrared light is obtained therefrom, and the incident angle β
Then, the distance L to the subject is obtained from the base length α of the light emitting element 30 and the light receiving element 32. The focal position in the direction of the optical axis is determined from the distance L, and the optical system or the CCD is moved in the direction of the optical axis for adjustment. As for the tilt direction, the tilt direction of the CCD imaging surface 11 is adjusted in the same configuration as described above.

FIG. 13 is a diagram showing another example of the configuration of the CCD imaging surface 11. The CCD imaging surface 11 has an imaging area 11d,
11e, 11f, and a tilt axis 15. In this case, a one-dimensional sensor is used as the light receiving element 32, and the imaging area 11d is set as a measurement area near the tilt axis 15 when the CCD imaging surface 11 is viewed from the optical axis direction.
Further, the tilt shaft 15 is provided on the CCD imaging surface 11 similarly to other device configurations. In the tilt direction, a separately set imaging area 11e or 11f is used as an evaluation area, and focus determination is performed using an evaluation value such as a high-frequency component. These imaging areas can be controlled more accurately if they are as far away as possible in the vertical direction of the tilt axis 15. In this example, the distance measuring means using infrared rays has been described.
Another distance measurement method such as a phase difference method may be used.

(Embodiment 4) FIG. 14 is a diagram showing an example of a configuration in a case where two distance measuring means shown in FIG. 12 are installed.
In the figure, 30a and 30b are infrared LEDs. here,
FIG. 14 is a side view of the infrared LED shown in FIG. 12, and shows a state in which two infrared LEDs 30a and 30b are vertically stacked in two stages. These two distance measuring means operate independently, and the principle of each is shown in FIG.
Is the same as that shown in FIG.

FIG. 15 is a diagram showing another example of the configuration of the CCD imaging surface 11. The CCD imaging surface 11 has an imaging area 11g,
11h and a tilt axis 15. On the CCD imaging surface 11, these two imaging areas 11g and 11h are arranged vertically about the tilt adjustment tilt axis 15. From these two pieces of measurement information, the optical position of the corresponding imaging area on the CCD imaging surface 11 can be determined, and the in-focus position and the tilt amount can be calculated. Also in this case, the external distance measuring means may be of an infrared type or another type such as a phase difference type.

FIG. 16 is a diagram for explaining an example of the tilt correction in the electronic image pickup apparatus 10. Here, for the sake of simplicity, a description will be given of the tilt correction of only one axis. FIG.
The principle is described below, and it is assumed that the plane of the subject 1 is perpendicular to the drawing. When performing a tilt adjustment on a planar subject, the plane of the subject 1, the plane passing through the lens surface and perpendicular to the optical axis, and the imaging plane intersect on one straight line as shown in FIG. Intersection). At this time, the tilt amount δ of the imaging plane with respect to the lens plane is obtained from the above-described tilt control amount.

Also, the distance L ₂ between the imaging plane and the lens plane
Is obtained from the focus adjustment amount. Accordingly, the distance L ₃ to triple intersection described above from the lens center can be calculated by Equation (1) shown below. L ₃ = L ₂ / tan δ Equation (1) Since the distance L ₁ between the lens and the object is obtained from the in-focus position, the angle θ between the lens plane and the object plane is obtained by the following equation (2). Can be. θ = tan ⁻¹ (L ₁ / L ₃ ) Expression (2) Here, θ indicates an angle between the lens optical axis and the normal to the object plane. Therefore, the “angle θ” obtained from the tilt amount δ and the focus adjustment amount can be obtained by the following equation (3). θ = tan ⁻¹ {(L ₁ / L ₂ ) tan δ} Equation (3)

In general, in the case of imaging in which the imaging surface and the subject are not parallel, the image can be converted into a parallel image by rotating the coordinates by an angle formed by both normals. In general, a camera coordinate system (x, y, 1) ) To the subject coordinate system (u, v, 1) is shown in the following determinant (4).

[0062]

(Equation 1)

A conversion equation for performing coordinate conversion using the above equation (4) is shown in the following equation (5).

[0064]

(Equation 2)

Therefore, in this example, first, the object is viewed from the front by rotating the imaging plane by the amount of inclination δ with respect to the optical axis, and further calculating the coordinate rotation by the amount of inclination θ of the optical axis with respect to the object plane (optical axis). And the subject normal vector). Here, a description has been given of only the one-axis direction. However, it is also possible to obtain a three-dimensional camera posture from the amount of tilt in a plurality of directions, and perform distortion correction using the above-described coordinate rotation formula.

[0066]

According to the first aspect of the present invention, the focus position is adjusted by displacing the optical system in the optical axis direction, and the tilt angle adjusting means in the tilt direction about the axis perpendicular to the optical axis direction is provided. By doing so, it is possible to obtain an image in which the front surface is focused even on a subject on a plane inclined from a plane perpendicular to the optical axis.

According to the second aspect of the present invention, the image pickup device such as a CCD is displaced in the optical axis direction to adjust the focal position, and the tilt angle adjusting means in the tilt direction about the axis perpendicular to the optical axis direction. Is provided, an image in which the front surface is in focus can be obtained even with a simpler configuration even for a subject on a plane inclined from a plane perpendicular to the optical axis.

According to the third aspect of the present invention, the focus position is adjusted and controlled by using a high-frequency component of an arbitrary image pickup area in the output of the image pickup device to adjust the focal position, without providing a separate element externally. be able to.

According to the fourth aspect of the present invention, by providing the tilt axis for tilt adjustment on the imaging surface of the image sensor, it is possible to prevent the focal position in the optical axis direction from being shifted by the tilt angle adjusting means.

According to the fifth aspect of the present invention, only the high-frequency component of the imaging area near the tilt axis is used for adjusting the focal position in the optical axis direction, so that the tilt angle adjusting means prevents the focus from being shifted. And no need for refocusing.

According to the sixth aspect of the present invention, by using the imaging area set in the direction perpendicular to the tilt axis as the tilt angle adjusting means, it is possible to adjust the tilt more precisely.

According to the seventh aspect of the present invention, the focus adjustment mechanism is operated in full stroke in advance, and the amount of tilt of the imaging surface is calculated by measuring the in-focus positions of two or more points in the imaging surface, thereby operating at high speed. be able to.

According to the eighth aspect of the present invention, the accuracy of calculating the amount of tilt can be improved by taking two or more measurement points in the imaging plane in a direction perpendicular to the tilt axis.

According to the ninth aspect of the present invention, in adjusting the focus position and the tilt amount, the control circuit is simplified by setting the maximum value of the high frequency component as the control target, and the focus and the tilt can be adjusted with high accuracy. Becomes

According to the tenth aspect, the operation can be sped up by adjusting the focal position using an external distance measuring means for measuring the distance to the subject.

According to the eleventh aspect of the present invention, the measurement area of the distance measuring means is made coincident with the imaging area in the vicinity of the tilt axis in the tilt angle adjusting means, so that the tilt angle adjusting means does not shift the focus. Can be.

According to the twelfth aspect, by using the imaging area set in the direction perpendicular to the tilt axis as the tilt angle adjusting means, it is possible to adjust the tilt more precisely.

According to the thirteenth aspect of the present invention, in adjusting the focus position and the tilt amount, the maximum value of the high-frequency component is set as the control target, thereby simplifying the control circuit and enabling highly accurate focus and tilt adjustment. become.

According to the fourteenth aspect, by measuring the distance to the subject at two or more locations, the amount of tilt can be calculated and the operation can be performed at higher speed.

According to the fifteenth aspect, the measurement accuracy of the distance to the subject is set in the direction perpendicular to the tilt axis, so that the correction accuracy can be improved.

According to the sixteenth aspect of the present invention, it is possible to obtain a front image by a simple calculation by performing image distortion correction by using a tilt amount obtained from a control amount obtained as a result of controlling the focus position and the tilt amount as a parameter. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an electronic imaging device to which the present invention is applied.

FIG. 2 is a diagram showing a configuration example of a CCD tilt mechanism to which the present invention is applied.

FIG. 3 is a diagram illustrating another configuration example of the electronic imaging device to which the present invention is applied.

FIG. 4 is a diagram showing another configuration example of the CCD tilt mechanism to which the present invention is applied.

FIG. 5 is a block diagram illustrating an example of an internal configuration of a control unit of the electronic imaging device to which the present invention is applied.

FIG. 6 is a diagram illustrating a configuration example of a CCD imaging surface to which the present invention is applied.

FIG. 7 is a diagram illustrating an operation example of a CCD imaging surface.

FIG. 8 is a diagram illustrating a change in a high-frequency component at an arbitrary position on a CCD imaging surface.

FIG. 9 is a diagram illustrating an operation example of a CCD imaging surface.

FIG. 10 is a diagram illustrating an example of a relationship between a high-frequency component of a video signal and a CCD position.

FIG. 11 is a flowchart illustrating an example of an algorithm for obtaining a peak of a high-frequency component.

FIG. 12 is a diagram showing another configuration example of a device using a distance measuring unit using infrared rays.

FIG. 13 is a diagram illustrating another configuration example of the CCD imaging surface.

FIG. 14 is a diagram showing a configuration example when two distance measuring units shown in FIG. 12 are installed.

FIG. 15 is a diagram illustrating another configuration example of the CCD imaging surface.

FIG. 16 is a diagram illustrating an example of a tilt correction in the electronic imaging device.

FIG. 17 is a diagram illustrating a configuration example of a conventional photographing apparatus.

FIG. 18 is a diagram illustrating a configuration example of a camera with a tilt function.

[Explanation of symbols]

1, 31 subject, 1a farthest contact, 1b closest contact,
10: Electronic imaging device, 11: CCD imaging surface, 11a, 1
1b, 11c, 11d, 11e, 11f, 11g, 11
h: imaging area, 12: optical focus adjustment mechanism, 13: C
CD tilt mechanism, 14: camera optical axis, 15: tilt axis, 16
... Rotation actuator, 17 ... Translation actuator, 20 ... Control unit, 21 ... CCD, 22 ... Frame memory, 23 ... High frequency component extractor, 24 ... Adder, 25 ... Memory, 26 ... CPU, 27 ... Optical system, 30, 30a, 3
0b: infrared LED (light emitting element), 32: PSD (light receiving element), 40: photographing device, 41: lens, 42: imaging surface (film surface), 43: optical axis.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 15/00 G02B 7/11 N 19/02 D // H04N 101: 00 G03B 3/00 A F term ( Reference) 2H011 AA03 BA33 BB02 BB04 CA21 2H051 AA00 BA47 CB22 CB27 CE14 DA03 DA05 DA10 DA19 DD05 DD10 DD20 FA48 GB12 2H054 AA01 BB00 BB11 5C022 AA13 AB24 AB26 AB27 AB29 AB45 AB46 AC27 AC42 CA07

Claims (16)

[Claims] 1. An optical imaging means for imaging an object image included in a field of view on a plane, and an optical signal abutting on the formed plane, and a spatial light amount on the plane being measured by using an image sensor. A focus position adjusting means for adjusting a focus position by displacing the optical image forming means, and an electronic image pickup means having an axis perpendicular to an optical axis. An electronic imaging apparatus comprising: a tilt angle adjusting unit that holds an imaging surface of an imaging unit so as to be tiltable in at least one axis and adjusts an imaging surface of the electronic imaging unit to an arbitrary tilt angle. 2. An optical imaging means for imaging an object image contained in a field of view on a plane, and an electric signal which is in contact with the formed plane, and which uses an image sensor to measure a spatial light amount on the plane. A focus position adjusting means for adjusting a focus position by displacing an image sensor of the electronic imaging means in an optical axis direction of the optical imaging means; Tilt angle adjusting means for holding an image pickup surface of the electronic image pickup means so as to be tiltable about at least one axis about an axis perpendicular to the axis, and adjusting the image pickup surface of the electronic image pickup means to an arbitrary inclination angle. An electronic imaging device characterized in that: 3. The electronic imaging device according to claim 1, wherein an imaging area of the electronic imaging unit is specified so that an electric signal of an arbitrary area converted by the electronic imaging unit can be extracted as a video signal. An imaging area specifying unit, a frequency component extracting unit that extracts an arbitrary frequency component in a video signal extracted from the specified imaging area, a storage unit that stores a value of the extracted frequency component, and a storage unit that stores a value of the extracted frequency component. A comparison determination unit that determines by comparing a frequency component with a frequency component stored immediately before, and operates and controls the focus position adjustment unit and the tilt angle adjustment unit based on a determination output of the comparison determination unit. An electronic imaging apparatus, comprising: a control unit. 4. The electronic imaging device according to claim 1, wherein an inclination axis of said inclination angle adjusting means is provided on an imaging surface of said electronic imaging means. 5. The electronic imaging apparatus according to claim 4, wherein an imaging area that is coincident with or close to the tilt axis is set as an evaluation area, and only an output of a video signal in the evaluation area is set as an evaluation value. An electronic imaging apparatus, wherein the focus adjustment is performed by the focus position adjusting means based on the value, and an imaging area different from the evaluation area is used for the operation of the tilt angle adjusting means. 6. The electronic imaging device according to claim 5, wherein output of video signals in at least two or more imaging areas at different positions in a direction perpendicular to the tilt axis is an evaluation value, and based on the evaluation value. An electronic imaging device, wherein an inclination angle of the imaging surface is adjusted. 7. The electronic imaging apparatus according to claim 1, wherein the focus position adjusting unit operates when an imaging surface of the electronic imaging unit forms a certain angle with respect to an optical axis. The focus position specifying means for specifying the focus positions of at least two or more image pickup areas in the image pickup plane; and the storage means for storing the specified focus positions. An electronic imaging apparatus, wherein an inclination amount of the imaging surface is determined based on a focus position. 8. The electronic imaging apparatus according to claim 7, wherein output of video signals in at least two or more imaging areas at different positions in a direction perpendicular to the tilt axis is used as an evaluation value, and based on the evaluation value. An electronic imaging apparatus, wherein an inclination amount of the imaging surface is obtained. 9. The electronic imaging device according to claim 6, wherein a high-frequency component in an imaging area is used as the evaluation value, and a maximum point of the high-frequency component is determined by a tilt amount of the imaging surface,
An electronic imaging apparatus, which is a control target of a focus position. 10. The electronic imaging apparatus according to claim 1, further comprising: a distance measuring unit that measures a distance to a subject, wherein the focal position adjusting unit is configured to control the focal position adjusting unit based on a measurement value measured by the distance measuring unit. Controlling, and an imaging area specifying means for specifying an imaging area of the electronic imaging means so that the electric signal converted by the electronic imaging means can be extracted as a video signal; and a video signal extracted from the specified imaging area. Frequency component extraction means for extracting an arbitrary frequency component, storage means for storing the value of the extracted frequency component, and comparison for determining by comparing the extracted frequency component with the frequency component stored immediately before Determining means, and control means for operating and controlling the focal position adjusting means and the tilt angle adjusting means based on the determination output of the comparing and determining means. An electronic imaging device, comprising: 11. The electronic imaging apparatus according to claim 10, wherein the measurement area of the distance measurement unit corresponds to an imaging area on or near an inclination axis of an imaging surface of the electronic imaging unit. Electronic imaging device. 12. The electronic imaging apparatus according to claim 10, wherein output of video signals in at least two or more imaging areas at different positions in a direction perpendicular to the tilt axis is an evaluation value, and based on the evaluation value. An electronic imaging device, wherein an inclination angle of the imaging surface is adjusted. 13. The electronic imaging device according to claim 12, wherein a high-frequency component in an imaging area is used as the evaluation value, and a maximum point of the high-frequency component is set as a control target of the tilt amount of the imaging surface. Electronic imaging device. 14. The electronic imaging apparatus according to claim 1, wherein a distance measuring unit that measures a distance to the subject, and a changing unit that can selectively change a measurement position of the distance measuring unit within a field of view. And storage means for storing the distance to the subject at at least two or more measurement points in the field of view, wherein the focus position adjusting means and the tilt angle adjusting means are based on the measured distance to the subject. An electronic imaging device characterized by operating and controlling the device. 15. The electronic imaging device according to claim 14, wherein at least two or more imaging areas are provided at different positions in a direction perpendicular to the tilt axis. 16. The electronic imaging apparatus according to claim 1, further comprising a tilt amount calculating means for calculating a tilt amount from a tilt control amount controlled by said tilt angle adjusting means. Obtaining an angle between an optical axis of the optical imaging means and a normal direction of a subject plane based on the tilt amount obtained, and calculating and correcting a distortion with respect to an image output from the electronic imaging means based on the formed angle. An electronic imaging device characterized by the above-mentioned.