JP2010011042A - Tilt correction method for imaging apparatus, and tilt-correcting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt correction method of an imaging apparatus and a tilt-correcting apparatus, capable of accurately correcting an inclination of an imaging element, with respect to the optical axis direction, using a simple configuration. <P>SOLUTION: In a tilt-correcting techniques for correcting the inclination of the imaging element 8 by driving tilt correcting elements 13a to 13c disposed discretely around the optical axis and connected to the imaging element 8, the focusing position of a focusing lens 5 is detected in each of pickup patterns TP0 to TP4 and is focused on the imaging element 8, by associating with the amount of slide in the optical axis direction of the focusing lens 5 in focusing position detecting means 24. Then the amount of displacement of the focusing position of the other pickup pattern, relating to the focusing position of the pickup pattern TP0 for reference, is detected, and the driving amounts of the tilt-correcting elements 13a to 13c are calculated so that the focusing positions of the focusing lens 5 in the pickup patterns TP0 to TP4 coincide with one another, based on the amount of displacement detected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tilt correction method for correcting an inclination of an image sensor with respect to an optical axis of an image pickup apparatus including an image pickup lens that guides an optical image to the image sensor and an image sensor that photoelectrically converts the optical image and outputs an image signal. And a tilt correction device.

  Conventionally, a subject image (a so-called optical image) is formed on an image sensor (for example, CCD: Charge Coupled Devices, CMOS: Complementary Metal Oxide Semiconductor, etc.) through an imaging lens, and photoelectrically converted to generate an image signal. An imaging device (for example, a digital camera) is known.

  Some image pickup devices are required to have high accuracy in mounting an image pickup device in accordance with the need for higher resolution, and have a tilt correction that corrects the tilt of the image pickup device with respect to the optical axis of the imaging system that guides an optical image. is there. That is, in the imaging apparatus, even if the center of the imaging surface is in focus, the focus near the periphery of the screen may be shifted depending on the tilt of the imaging element. The correction is made to correct it.

  For example, in the manufacturing process of the imaging apparatus, the operator evaluates the degree of focus while viewing the captured image, and corrects the tilt of the imaging element by manual operation. In this case, generally, there is a problem that the amount of tilt cannot be quantitatively evaluated, the correction accuracy is impaired, and the correction time is longer than necessary.

  On the other hand, a technique is known that detects the amount of tilt and automatically corrects the tilt of captured image data. For example, an imaging apparatus such as an electronic camera includes an angle sensor that detects a tilt angle of the camera with respect to a horizontal axis, and a distance measuring unit that detects a distance from the camera to a subject (hereinafter referred to as a subject distance). A technique is disclosed in which tilt correction is performed by correcting image data formed on an image sensor in accordance with the tilt angle and subject distance (see, for example, Patent Document 1).

  As another example, the imaging area is divided into a plurality of areas, and the focus information (so-called information indicating the degree of focus) for each area is used to determine the relationship between the imaging plane of the image sensor and the optical axis of the imaging system. There is also known a technique for detecting the tilt angle and correcting the tilt by adjusting the tilt of the image sensor based on the detected tilt angle.

  For example, a horizontal tilt correction drive mechanism that detects a tilt angle for each of the horizontal direction and the vertical direction orthogonal to each other and correlates with these tilt angles to tilt the image sensor in the horizontal direction to correct the horizontal tilt. A vertical tilt correction drive mechanism that tilts the image sensor in the vertical direction to correct vertical tilt; A technique for correcting the tilt by driving the horizontal tilt correction drive mechanism and the vertical tilt correction drive mechanism using the tilt correction drive parameters stored in advance in the EEPROM is disclosed.

In this case, the imaging device is supported so as to be tiltable along the horizontal direction via a support shaft extending in the vertical direction, and along the vertical direction via a support shaft extending in the horizontal direction. It is configured to be tiltable about these support shafts (see, for example, Patent Document 2).
JP 2004-147138 A Japanese Patent Laid-Open No. 11-242152

  However, the tilt correction technique described in Patent Document 1 corrects the image data formed on the image sensor without correcting the tilt of the image sensor itself, and cancels the tilt angle of the optical axis with respect to the subject. This is a technique for correcting image data, and is used while the tilt angle (tilt angle) of the image sensor with respect to the optical axis of the imaging optical system is present. Therefore, there is a possibility that image accuracy may be impaired due to an error in image correction. In addition, according to the tilt correction technique described in Patent Document 1, there is a problem that a load (for example, an arithmetic circuit) in image correction processing increases as the number of pixels of the image sensor increases.

  Further, the tilt correction technique described in Patent Document 2 depends on two axes in the horizontal direction and the vertical direction. For example, when the tilt center of the tilt of the image sensor does not coincide with the horizontal direction or the vertical direction, The time required for correction because the correction operation by the horizontal tilt correction climate and the vertical tilt correction mechanism does not affect the tilt direction accurately, and the correction accuracy is impaired or the correction operation needs to be repeated. May exceed the allowable range.

  In the tilt correction technique described in Patent Document 2, the accuracy of tilt correction depends on the support mechanism of the image sensor (accuracy to support the image sensor in the horizontal and vertical directions orthogonal to each other) and the tilt correction drive mechanism. Therefore, there is a possibility that the cost for accurately configuring these mechanism units increases and the productivity is impaired.

  Therefore, the present invention does not require a precise horizontal and vertical drive mechanism for the image sensor when correcting the tilt in the image pickup apparatus, and the center of rotation of the image sensor tilt is horizontal or vertical. It is an object of the present invention to provide a tilt correction method and a tilt correction device that can obtain a high accuracy with a relatively simple configuration without being restricted by the rotation center even when they do not coincide with each other.

  The invention according to claim 1, which has been made to achieve the above object, includes an imaging lens that is slidably installed along an optical axis direction of incident light and guides an object image to an imaging device, and the imaging lens is arranged as the light. In the imaging device comprising: a slide mechanism that slides along the axial direction; and the imaging device that photoelectrically converts the subject image formed through the imaging lens and outputs an image signal, the imaging device includes: A plurality of tilt correction elements discretely arranged around the optical axis are connected, and the tilt of the imaging surface of the image sensor with respect to the optical axis of the incident light is corrected by driving the plurality of tilt correction elements. This is a tilt correction method in which a plurality of imaging patterns discretely arranged on a predetermined chart are imaged, the imaging lens is slid in the optical axis direction through the slide mechanism, and the scan is corrected. An in-focus position detecting step for detecting an in-focus position in the optical axis direction of the imaging lens for each of the plurality of imaging patterns imaged on the imaging element in association with an id amount; and the in-focus position Based on the deviation amount detection step for detecting the deviation amount of the in-focus position for each of the plurality of imaging patterns detected in the detection step, and the deviation amount detected in the deviation amount detection step, the plurality of imaging patterns. A drive amount calculating step for calculating a drive amount of the plurality of tilt correction elements so that the in-focus positions at the same position, and an inclination of the imaging plane based on the drive amount calculated in the drive amount calculating step And an inclination correction step for correcting.

  According to the tilt correction method of the imaging apparatus according to claim 1, a plurality of tilt correction elements discretely arranged around the optical axis are connected to the image sensor, and the plurality of tilt correction elements are driven. A tilt correction method for correcting the tilt of the imaging surface of the image sensor with respect to the optical axis of incident light. First, in the focus position detection step, a plurality of imaging patterns discretely arranged on a predetermined chart The image pickup lens is slid in the optical axis direction, and the in-focus position in the optical axis direction of the image pickup lens is detected for each of a plurality of image pickup patterns formed on the image pickup device in association with the slide amount. .

  Next, in the shift amount detection step, the shift amount of the focus position for each of the plurality of imaging patterns detected in the focus position detection step is detected, and then in the drive amount calculation step, the shift detected in the shift amount detection step. Based on the amount, the drive amount of the plurality of tilt correction elements is calculated so that the in-focus positions in the plurality of imaging patterns match, and then, in the inclination correction step, based on the drive amount calculated in the drive amount calculation step Thus, the tilt of the image plane is corrected.

  Thus, the tilt correction method of the imaging device according to claim 1 does not require a precise horizontal and vertical drive mechanism with respect to the image sensor when correcting the tilt, and the tilt of the image sensor is rotated. Even when the center does not coincide with the horizontal direction or the vertical direction, the tilt center is not restricted, and high accuracy can be obtained with a relatively simple configuration.

  According to a first aspect of the present invention, the tilt correction method of the imaging apparatus includes a focus evaluation value obtained by sliding the imaging lens in the optical axis direction in the focus position detecting step. A change curve is detected, and the imaging lens is slid in the optical axis direction so as to pass a peak point of the focus evaluation value in the change curve, and a position of the imaging lens corresponding to the peak point is detected as a focus position. It is preferable.

  The tilt correction method for an image pickup apparatus according to claim 1 or 2, as in the invention according to claim 3, focuses on the image pickup lens based on an image signal output from the image pickup element. Preferably, a reference position detection step for detecting a reference position of the position is provided, and in the shift amount detection step, a shift amount between the reference position and the focus position of the imaging lens for each of the plurality of imaging patterns is preferably detected. . ,

  The tilt correction method for an imaging apparatus according to any one of claims 1 to 3 is the drive amount for each of the plurality of tilt correction elements in the drive amount calculation step as in the invention according to claim 4. When a response matrix composed of the change amount of the in-focus position with respect to is generated, and the response matrix is represented by R, the drive amount is represented by a, and the variation amount is represented by b, the drive amount a is determined from Ra = b. By the solution of the following equation, the drive amount for each tilt correction element can be obtained.

  According to a fourth aspect of the present invention, the response correction method of the imaging apparatus is configured such that the response matrix R sets the number of the plurality of imaging patterns to M and the number of the plurality of tilt correction elements. When expressed as N, it may be configured by M rows and N columns, and a component constituting this matrix may be the amount of change.

  The tilt correction method for an image pickup apparatus according to any one of claims 1 to 3, as in the invention according to claim 6, is two directions orthogonal to the optical axis direction and the optical axis. A plane in which the difference from the in-focus positions of the plurality of imaging patterns detected in the in-focus position detecting step is the smallest in the three-dimensional coordinate system is defined as a focus plane. Detecting and then correcting the tilt so as to cancel the tilt of the tilt focusing plane with respect to the reference focusing plane when a plane perpendicular to the optical axis is used as a reference focusing plane at a predetermined focusing reference position. It is preferable to generate a driving amount of the element.

  Further, according to the tilt correction method of the imaging apparatus according to any one of claims 1 to 6, the drive amounts of the plurality of tilt correction elements detected in the drive amount calculation step are calculated as in the invention according to claim 7. By providing the presenting step to be presented to the user, the user can easily obtain the driving amount of the correction element and the convenience can be improved.

  The tilt correction method for an imaging apparatus according to any one of claims 1 to 7 is, as in the invention according to claim 8, wherein, in the drive amount calculation step, one of the plurality of tilt correction elements. One of them is locked in the direction of the optical axis, and a drive amount of the tilt correction for the other tilt correction elements excluding the one tilt correction element is calculated, and in the tilt correction step, the other tilts excluding the one tilt correction element are calculated. It is preferable to correct the tilt of the image plane by driving a correction element. As a result, the image sensor is locked in the optical axis direction by one tilt correction element, and tilt correction can be easily performed.

  The tilt correction method of the imaging apparatus according to any one of claims 1 to 7 is performed when any of the plurality of tilt correction elements is driven as in the invention according to claim 9. The image pickup device is tilted so that the straight line connecting the two tilt correction elements opposed to the drive target tilt correction element is the rotation axis, thereby further including a rotation axis that supports the image pickup element in a tiltable manner. There is no need to improve productivity.

  Next, the invention according to claim 10 is slidably installed along the optical axis direction of the incident light to guide the subject image to the image sensor, and slides the imaging lens along the optical axis direction. An image pickup apparatus comprising: a slide mechanism for causing the image pickup device to photoelectrically convert the subject image formed through the image pickup lens and outputting an image signal. A tilt correction device that is connected to a plurality of discrete tilt correction elements and corrects the inclination of the imaging plane of the image sensor with respect to the optical axis of the incident light by driving the plurality of tilt correction elements. Imaging a plurality of imaging patterns discretely arranged on a predetermined chart, sliding the imaging lens in the optical axis direction via the slide mechanism, and associating with the slide amount, Focus position detection means for detecting a focus position in the optical axis direction of the image pickup lens for each of the plurality of image pickup patterns formed on the image element, and the plurality of positions detected by the focus position detection means. The in-focus positions in the plurality of imaging patterns coincide with each other based on the amount of deviation detected by the amount of deviation detected by the amount of deviation detection means and the amount of deviation detected by the amount of deviation detection means. As described above, a drive amount calculation unit that calculates a drive amount of the plurality of tilt correction elements, an inclination correction unit that corrects an inclination of the imaging plane based on the drive amount calculated by the drive amount calculation unit, It is characterized by providing.

  Thus, the tilt correction device for the image pickup device according to the tenth aspect, like the invention according to the first aspect, requires a precise drive mechanism in the horizontal and vertical directions with respect to the image pickup device when correcting the tilt. Even when the pivot center of the tilt of the image sensor does not coincide with the horizontal direction or the vertical direction, it is not restricted by this pivot center, and high accuracy can be obtained with a relatively simple configuration.

  According to a tenth aspect of the present invention, there is provided a tilt correction device for the focus evaluation value of the focus position detection unit according to the slide in the optical axis direction of the imaging lens. A change curve is detected, and the imaging lens is slid in the optical axis direction so as to pass a peak point of the focus evaluation value in the change curve, and a position of the imaging lens corresponding to the peak point is detected as a focus position. It is preferable.

  Further, the tilt correction device of the imaging device according to claim 10 or 11, as in the invention according to claim 12, the tilt correction device is based on an image signal output from the imaging device. A reference position detecting unit for detecting a reference position of a focus position of the imaging lens, and the shift amount detecting unit detects a shift between the reference position and the focus position of the imaging lens for each of the plurality of imaging patterns. It is preferably configured to detect the quantity.

  In the tilt correction device for an imaging apparatus according to any one of claims 10 to 12, as in the invention according to claim 13, the drive amount calculation unit is configured to control the drive amount for each of the plurality of tilt correction elements. When a response matrix composed of the change amount of the in-focus position is generated, the response matrix is represented by R, the drive amount is represented by a, and the variation amount is represented by b, the drive amount a is Ra = b. By being configured to be the solution of the equation, it is possible to obtain the drive amount for each tilt correction element.

  Further, in the tilt correction device for an imaging apparatus according to claim 13, as in the invention according to claim 14, the response matrix R includes M as the number of the plurality of imaging patterns, and the plurality of tilt correction elements. When the number is expressed as N, it is preferable that the number of change elements is composed of M rows and N columns, and the component constituting the matrix is the amount of change.

  Further, the tilt correction device for an imaging apparatus according to any one of claims 10 to 12 includes the coordinate in the optical axis direction and the optical axis, as in the invention according to claim 15. A three-dimensional coordinate system composed of coordinates in two directions orthogonal to each other, and in the three-dimensional coordinate system, the difference from the in-focus positions of the plurality of imaging patterns detected by the in-focus position detecting means Is provided with a tilt plane detection means for detecting the plane with the smallest focus as a focus plane, and the imaging model driving amount calculation means sets a plane orthogonal to the optical axis at a predetermined focus reference position as a reference focus plane. In this case, it is preferable that the drive amount of the tilt correction element is generated so as to cancel the tilt of the tilt focus surface with respect to the reference focus surface.

  The tilt correction apparatus for an imaging apparatus according to any one of claims 10 to 15 is configured to drive the plurality of tilt correction elements calculated by the drive amount calculation unit as in the invention according to claim 16. By providing the presenting means for presenting the amount to the user, the user can easily obtain the driving amount of the correction element and improve the convenience as in the case of the seventh aspect of the invention.

  Further, in the tilt correction device for an imaging apparatus according to any one of claims 10 to 16, as in the invention according to claim 17, the drive amount calculation unit includes one of the plurality of tilt correction elements. 9. The same as the invention according to claim 8, wherein one of the two is corrected in the optical axis direction, and a drive amount for correcting the tilt with respect to other tilt correcting elements excluding the one tilt correcting element is calculated. In addition, the image sensor is locked in the optical axis direction by a single tilt correction element, and tilt correction can be easily performed.

  The tilt correction device for an imaging apparatus according to any one of claims 10 to 17 is configured to drive any one of the plurality of tilt correction elements as in the invention according to claim 18. In the same manner as in the invention according to claim 9, the image pickup device is tilted with a straight line connecting the two tilt correction elements facing the drive target tilt correction element as a rotation axis. Further, it is not necessary to separately provide a rotating shaft that supports the image pickup device so as to be tiltable, and productivity can be improved.

  In the tilt correction method and tilt correction apparatus of the imaging apparatus according to the present invention, a plurality of tilt correction elements discretely arranged around the optical axis are connected to the imaging element, and are discretely arranged on a predetermined chart. A plurality of image pickup patterns are imaged to calculate a correction amount of the tilt, and a plurality of tilt correction elements are driven according to the correction amount to correct the tilt. A precise drive mechanism in the vertical direction is not required, and even when the pivot center of the tilt of the image sensor does not coincide with the horizontal direction or the vertical direction, the tilt center is not restricted, and the structure is relatively simple. High accuracy can be obtained.

  Also, the tilt correction method and tilt correction apparatus of the imaging apparatus according to the present invention generates a response matrix configured by the amount of change in the in-focus position with respect to the drive amount for each of the plurality of tilt correction elements, and drives the response matrix as R. When the amount is expressed as a and the amount of change is expressed as b, the drive amount for each tilt correction element can be obtained with high accuracy by calculating the drive amount a so that it is a solution of the equation of Ra = b. .

  Further, the tilt correction method and tilt correction apparatus of the imaging apparatus according to the present invention provide a correction between two tilt correction elements facing the target tilt correction element when one of a plurality of tilt correction elements is driven. Since the image sensor is tilted about a straight line connecting the two as a rotation axis, it is not necessary to separately provide a rotation axis that supports the image sensor so as to be tiltable, and productivity can be improved.

(First embodiment)
Next, a tilt correction method and tilt correction apparatus for an imaging apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the tilt correction device of the imaging apparatus of the first embodiment, FIG. 2 is a structural diagram of the imaging apparatus of the first embodiment, and FIG. 3 is a direction from the arrow Z in FIG. FIG. 2 is a structural diagram of the imaging device viewed from above.

  FIG. 4 is a flowchart showing the procedure of the tilt correction method of the imaging apparatus of the first embodiment, FIG. 5 is a flowchart showing the adaptive matrix generation procedure in the flowchart of FIG. 4, and FIG. FIGS. 5A and 5B are diagrams for explaining the effect of tilt correction in the first embodiment, in which FIG. 5A shows a focus evaluation curve before correction and FIG. 5B shows a focus evaluation curve after correction.

  As shown in FIG. 1, the tilt correction device 1 of the imaging apparatus of the present embodiment captures an image of the imaging plane of the imaging element 8 with respect to the optical axis of incident light in the imaging apparatus 100 that captures a subject and outputs an image signal. It is configured to correct the tilt.

  The imaging apparatus 100 includes a front lens 2 that guides incident light into the imaging apparatus 100 along the optical axis direction (Z direction in FIG. 1), and the optical axis direction (in the figure, depending on the zoom magnification at the time of shooting). A zoom lens 3 that slides in the X direction), a light amount adjustment unit 4 that adjusts the amount of incident light, a focus lens 5 that guides the subject image to the image sensor 8, and a filter that removes harmful infrared rays and harmful reflected light ( By an image sensor (for example, a complementary metal oxide semiconductor (CMOS) sensor) 8 that photoelectrically converts a formed optical image and outputs a digital image signal for each pixel, etc. It is configured.

  The imaging apparatus 100 also includes a zoom lens driving unit 3M as a driving source for moving the zoom lens 3 in the optical axis direction, a light amount adjustment driving unit 4M as a driving source for driving the light amount adjustment unit 4, and the positions of the focus lens 5 and The detection unit 5S detects the amount of movement, the focus lens drive unit 5M as a drive source for moving the focus lens in the optical axis direction, and the like.

  As shown in FIG. 2, the imaging apparatus 100 includes a front lens 2, a light amount adjustment unit 4, a filter 6, and the like inside casings 1 a, 1 b, and 1 c that are formed of a synthetic resin material and are integrally joined. Is fixed, and the zoom lens 3 and the focus lens 5 are supported by the support members 3a and 5a so as to be slidable in the optical axis direction.

  The edge of the filter 6 is sandwiched between a casing 1c and a filter spacer 7 made of an elastic body, and is supported by the casing 1c. The filter spacer 7 is configured to elastically contact the edge of the filter 6 and the image sensor 8 to hold the filter 6 in the casing 1c and to prevent incident light from leaking.

  In addition, an image sensor 8 is disposed on the opposite side of the front lens 2 via the focus lens 5, and the image sensor 8 is fixed to the first sensor board 9, and via a tilt correction mechanism described later, The casing 1c is supported so as to be tiltable.

  In addition, the imaging device 100 is fixed to the outside of the casings 1a, 1b, and 1c, and is fixed to the end surface in the optical axis direction of the casing 1c, and is formed with an insertion hole through which the imaging element 8 and the first sensor board 9 are inserted. 12, a second sensor board 11 that relays an image signal output from the image sensor 8 to the circuit board 14, a circuit board 14 on which a circuit that controls the operation of the imaging device 100 is mounted, and the like.

  Further, as shown in FIG. 2, the image signal output from the image sensor 8 is connected by the connection between the connector 16 a mounted on the first sensor board 9 and the connector 16 b connected to the second sensor board 11. The second sensor board 11 is led.

  One end of the second sensor board 11 is connected to the circuit board 14, and the image signal output from the image sensor 8 is connected to a circuit on the circuit board 14. The circuit board 14 includes a circuit for processing an image signal output from the image sensor 8 and controlling operations of the zoom lens 3, the light amount correction unit 4, the focus lens 5, and the like.

  Next, the imaging apparatus 100 includes the above-described tilt correction mechanism that corrects the inclination of the imaging element 8 with respect to the optical axis of incident light that is incident through the lens groups 2, 3, and 5.

,
As shown in FIGS. 2 and 3, the tilt correction mechanism is discretely arranged along the periphery of the optical axis and the support member 10 that supports the image sensor 8 via the first sensor board 9. A pair of three urging members 14a, 14b, 14c elastically contacting the support member 10 along the optical axis direction and urging members 14a, 14b, 14c are provided, and the shaft portion is the support member 10 and the urging member 14a. 14b and 14c, one end of the shaft portion engages with the support member 10, and the other end of the shaft portion is screwed into the casing 1c, and slides in the optical axis direction along with the screwing to support member 10. And tilt correction elements 13a, 13b, and 13c for tilting together with the image sensor 8. It should be noted that the function of the tilt correction element in the present invention is expressed by the tilt correction elements 13a, 13b, and 13c.

  Specifically, the plate-like fixing member 12 is fixed to the casing 1c and disposed in a direction facing the support member 10, and the support member 10 passes through the fixing member 12 and the lens groups 2, 3 along the optical axis direction. 5, and biasing members 14 a, 14 b, and 14 c are disposed between the fixing member 12 and the support member 10.

  The fixing member 12 is provided with a sealing hole formed with a threaded portion in which the shaft portions of the tilt correction elements 13a, 13b, and 13c are combined, and the tilt correction elements 13a, 13b, and 13c are arranged in the casing via the fixing member 12. 1c, there is a support member 10, which is supported by the fixing member 12 by the correction elements 13a, 13b, 13c. Moreover, the fixing member 12 and the supporting member 10 are formed using steel materials (for example, stainless steel etc.) excellent in durability.

  The biasing members 14a, 14b, and 14c are compression coil springs wound around the shaft portions of the tilt correction elements 13a, 13b, and 13c. One end of the biasing members 14a, 14b, and 14c contacts the support member 10 and the other end is fixed. It is configured to abut against the member 12. The tilt correction elements 13a, 13b, and 13c are small screws each having a top portion having a larger diameter than the shaft portion and a shaft portion that extends from the top portion and has a helical thread portion. The seat 12a is formed so as to protrude from the fixing member 12 and is screwed.

  Further, the support member 10 is formed with a recess facing the seat 12a and being recessed on the opposite side of the fixing member 12, and the biasing members 14a, 14b, 14c and the tilt correction elements 13a, 13b, 13c is attached.

  Also, as shown in FIG. 3, a plurality of urging members 14a, 14b, 14c and tilt correction elements 13a, 13b, 13c are provided at positions that constitute the apex of the triangle, and are arranged at equal intervals, respectively. Yes. That is, the distance between the biasing member 14a and the tilt correction element 13a and the biasing member 14b and the tilt correction element 13b, the distance between the biasing member 14b and the tilt correction element 13b, the biasing member 14c and the tilt correction element 13c, and the biasing member 14a. The tilt correction element 13a and the biasing member 14c and the tilt correction element 13c are arranged to have the same distance. At this time, it is preferable that the tilt correction elements 13a, 13b, and 13c and the urging members 14a, 14b, and 14c are arranged on a concentric circle with the optical axis as the center.

  Further, as shown in FIG. 3B, two positioning pins 18a and 18b protrude in the optical axis direction from the end surface of the casing 1c, and the fixing member 12, the support member 10 and the like are loosely connected to the positioning pins. A through-hole that fits in is formed. The fixing member 12 and the support member 10 are positioned via the positioning pins 18a and 18b.

  In the tilt correction mechanism of this embodiment, when the tilt correction element 13a is rotated clockwise, the support member 10 is fixed to the fixing member 12 with the tilt correction elements 13b and 13c as fulcrums against the biasing force of the biasing member 14a. On the other hand, when the tilt correction element 13a is rotated counterclockwise, the support member 10 is tilted away from the fixed member 12 with the tilt correction elements 13b and 13c as fulcrums.

  Further, when the tilt correction element 13b is rotated clockwise, the tilt correction element 13a, 13c is tilted so that the support member 10 approaches the fixed member 12 against the biasing force of the biasing member 14b, with the tilt correction elements 13a and 13c as fulcrums, When the tilt correction element 13b is rotated counterclockwise, the support member 10 tilts away from the fixed member 12 with the tilt correction elements 13a and 13c as fulcrums.

  Further, when the tilt correction element 13c is rotated clockwise, the support member 10 is tilted so as to approach the fixing member 12 against the biasing force of the biasing member 14c with the tilt correction elements 13a and 13b as fulcrums, When the tilt correction element 13c is rotated counterclockwise, the support member 10 tilts away from the fixed member 12 with the tilt correction elements 13a and 13b as fulcrums.

  Next, as illustrated in FIG. 1, when correcting the tilt, the chart CH is photographed, and the rotation amounts of the tilt correction elements 13 a, 13 b, and 13 c are based on the digital image signal output from the imaging device 100. (The so-called drive amount of the present invention) is calculated by the tilt correction device 1. At this time, on the chart CH, the imaging pattern TP0 is arranged at a position corresponding to the optical center, and a plurality of imaging patterns TP1 to TP4 are arranged discretely around the imaging pattern TP0.

  The tilt correction device 1 stores a digital image signal output from the imaging device 100 in association with a pixel address, and stores the image patterns TP0 to TP4 based on the digital image signal stored in the field memory 21. The focus detection unit 22 detects the evaluation value of the degree of focus in association with the slide amount of the focus lens 5 in the optical axis direction, and the focus reference position (the main position) is detected based on the detection result of the focus detection unit 22. In the embodiment, the shift amount calculation means 25 for calculating the shift amount of the focus positions of the image pickup patterns TP1 to TP4 with respect to the focus lens 5 position corresponding to the focus position of the image pickup pattern TP0. Further, a tilt correction necessity determination means 26 for determining whether or not the tilt correction is necessary based on the calculation result of the deviation amount calculation means 25 is provided.

  Further, the tilt correction device 1 generates a parameter for the driving amount of the tilt correction elements 13a, 13b, and 13c for correcting the shift amount of the in-focus position, based on the determination signal indicating that the tilt correction is necessary. Parameter generation means 27, drive amount calculation means 30 for calculating drive amounts of the tilt correction elements 13a, 13b, 13c, and drive amounts of the tilt correction elements 13a, 13b, 13c calculated by the drive amount calculation means 30 are displayed in a predetermined manner. Drive amount display means 31 to be displayed on the device, buffer 34 for temporarily storing the calculation result in the tilt correction device 1, CPU 32, ROM 33, etc., and according to the control program stored in the ROM 33, the tilt correction device 1 And each process of the imaging device 100 is performed.

  As shown in FIG. 6A, the focus detection unit 22 measures the MTF (Modulation Transfer Function) of the captured image pattern for each slide (focus position) of the focus lens 5 to obtain a predetermined spatial frequency. MTF is detected as a focus evaluation value (that is, a contrast index is detected by measuring a change in MTF accompanying the movement of the focus lens 5). In FIG. 6 (a), TP0 to TP4 are focus evaluation value change curves associated with the slide in the optical axis direction of the focus lens (so-called imaging lens of the present invention) 5, and each symbol is a chart CH. It corresponds to the symbol.

Then, the focus detection unit 22 determines the position of the focus lens 5 that is the peak point of the focus evaluation value based on the image data of the imaging pattern TP0 in the focus reference position detection unit 23 (FIG. 6A). and it detects as a a) focus position P ₀ of TP0 in, at a focus position detecting means 24, based on the image data of the imaging pattern TP1 to TP4, the position of the focus lens 5 which is a peak of the focus evaluation value ( So-called in-focus position).

  At this time, the focus lens 5 is slid in the optical axis direction so as to pass the peak point of the focus evaluation value in the change curve, and the position of the focus lens 5 corresponding to the peak point is detected as the in-focus position. In addition, the function of the focus position detection means in the present invention is expressed by the focus detection means 22, and the function of the reference position detection means in the present invention is expressed by the focus reference position detection means 23.

Then, the deviation amount calculating means 25, as shown in (Equation 1), calculates the amount of deviation of the focus position of the imaging pattern TP1~TP4 for focusing the reference position _{P 0.} Hereinafter, the amount of deviation of the in-focus position of the imaging pattern P1 with respect to the in-focus reference position P ₀ is b ₁ , the amount of deviation of the in-focus position of the imaging pattern P ₂ with respect to the in-focus reference position P ₀ is b ₂ , and the in-focus reference position P. A deviation amount of the in-focus position of the imaging pattern TP3 with respect to _{0 is} represented as b ₃ , and a deviation amount of the in-focus position of the imaging pattern TP4 with respect to the in-focus reference position P ₀ is represented as b ₄ . In (Expression 1), P ₀ is the in-focus position of the imaging pattern TP ₀ , P ₁ is the in-focus position of the imaging pattern TP ₁ , P ₂ is the in-focus position of the imaging pattern TP ₂ , and P ₃ is the in-focus position of the imaging pattern TP ₃ ; P ₄ represents the focus position of the imaging pattern TP4. The function of the deviation amount detection means in the present invention is expressed by the deviation amount calculation means 25.

Next, the correction necessity determination unit 26 compares each of the deviation amounts b _{1 to} b ₄ with a predetermined threshold value, and if the deviation amount is within the threshold range, the tilt amount of the image sensor 8 is within an allowable range. Therefore, it is determined that the tilt correction is unnecessary. On the other hand, if the threshold is exceeded, it is determined that the tilt correction of the image sensor 8 is necessary. The correction necessity determination unit 26 transmits a signal representing the determination result to the drive amount presentation unit 31 when the tilt correction is not necessary, and drives the signal representing the determination result when the tilt correction is necessary. It transmits to the quantity calculation hand 30.

  Next, the parameter generation unit 27 generates a response matrix generation unit 28 that generates a change amount of the in-focus position with respect to the drive amount for each of the tilt correction elements 13a to 13c, and an inverse matrix of the response matrix generated by the response matrix generation unit 28. And adaptive matrix generation means 29 for generating.

Specifically, as shown in (Expression 2), the change amount of the focus position of the focus lens 5 corresponding to the imaging patterns TP1 to TP4 is a matrix element i, and the correspondence to the tilt correction elements 13a, 13b, and 13c is a matrix element. J. When the total number of measurement locations associated with the imaging pattern is expressed as M, and the number of tilt correction elements is expressed as N, the predetermined rotational drive amount of the tilt correction elements 13a, 13b, and 13c is represented by an M × N matrix element. The amount of change r _ij of the in-focus position for each imaging pattern associated with (for example, one rotation = 360 degrees) is arranged, and a response matrix R is generated.

In (Equation 2), a tilt correction device 13a when was driven by a predetermined amount, a change amount of the focus position of the imaging pattern TP1 is substituted into r _11, the amount of change in focus position of the imaging pattern TP2 to r ₂₁ assignment, and the amount of change in focus position of the imaging pattern TP3 substituted into r _31, substitutes the amount of change in focus position of the imaging pattern TP4 to r _41. Further, the tilt when the correction element 13b is driven, and the amount of change in focus position of the imaging pattern TP1 substituted into r _12, substitutes the amount of change in focus position of the imaging pattern TP2 to r _22, the imaging pattern TP3 The amount of change in the in-focus position is substituted for r _32, and the amount of change in the in-focus position of the imaging pattern TP 4 is substituted for r ₄₂ . Further, the tilt when the correction element 13c is driven, the amount of change in focus position of the imaging pattern TP1 is substituted into r _13, substituting the change amount of the focus position of the imaging pattern TP2 to r _23, the imaging pattern TP3 The amount of change in the in-focus position is assigned to r _33, and the amount of change in the in-focus position of the imaging pattern TP 4 is assigned to r ₄₃ .

Next, the adaptive matrix generation means 29 is an inverse matrix (A = R ⁻¹ of the response matrix generated by the response matrix generation means 28 as expressed in (Equation 3), and is also referred to as an adaptive matrix hereinafter. ) Is generated.

Next, the drive amount calculation unit 30 includes the inverse matrix (A = R ⁻¹ ) of the response matrix generated by the adaptive matrix generation unit 29 and the in-focus position shift amounts b ₁ and b calculated by the shift amount calculation unit. ₂ , b ₃ , and b ₄ are used to calculate the drive amount for tilt correction. At this time, if the drive amount of the tilt correction element 13a is a ₁ , the drive amount of the tilt correction element 13b is a ₂ , and the drive amount of the tilt correction element 13c is a ₃ , the tilt correction element is based on (Equation 4). The drive amount for each of 13a, 13b, and 13c is calculated. Note that the function of the drive amount calculation means in the present invention is expressed by the drive amount calculation means 30.

Next, the CPU 32 transmits the calculation result of the drive amount calculation unit 30 to the drive amount presentation unit 31. Further, the CPU 32 corrects the tilt of the image sensor 8 by applying a predetermined amount of rotation to the tilt correction elements 13a to 13c via a drive source (not shown) in response to a command signal from the user. The function of the presenting means in the present invention is expressed by the driving amount presenting means 30, and the function of the inclination correcting means in the present invention is expressed by the CPU 32.

  Next, the procedure of the tilt correction method in the present embodiment will be described with reference to FIGS. This procedure is executed by the CPU 14 giving a command signal to each function unit based on a program stored in the ROM 16. Further, S in FIGS. 4 and 5 represents a step.

  First, this procedure starts when a start signal is input to the tilt correction device 1 by the user, erases and initializes the previous calculation result stored in the buffer 34, and then proceeds to S100.

Next, in S100, the focus evaluation value (MTF) corresponding to the image pickup pattern TP0 is measured using the focus reference position detection unit 23 while sliding the focus lens 5 in the optical axis direction, and the focus evaluation value reaches a peak. The position (P ₀ ) of the focus lens 5 is detected as the focus reference position, and then the process proceeds to S200. The reference position detection step in the present invention corresponds to S100.

Next, in S200, the focus evaluation value corresponding to the slide amount of the focus lens 5 is obtained for each of the imaging patterns TP1 to TP4 while the focus lens 5 is slid in the optical axis direction using the focus position detection unit 24. (So-called focus evaluation value curve is measured), and this is recorded, and the position (P _{1 to} P ₄ ) of the focus lens 5 at which the focus evaluation value peaks is detected as the focus position. . The focus position detection step in the present invention corresponds to S100 and S200.

Then, in S300, by using the deviation amount calculation unit 25, the deviation amount between the position of the focus lens 5 which the imaging pattern TP1~TP4 is focused _(P 1 ~P ₄₎ for focusing the reference position _{(P 0)} (b _{1 to} b ₄ ) are calculated, and then the process proceeds to S400. The shift amount detection step in the present invention corresponds to S300.

Next, in S400, the correction necessity determination unit 26 is used to determine the necessity of correction by comparing the deviation amount (b _{1 to} b ₄ ) with a predetermined threshold value. When the deviation amount is equal to or less than the threshold value. If no correction is necessary, the process proceeds to S700. In S700, the driving amount presenting means 31 is used to present a correction end instruction signal, and the tilt correction processing procedure ends. On the other hand, if the amount of deviation is larger than the threshold value in S400, the correction is necessary and the process proceeds to S500.

Next, in step S500, the drive amount calculation means 30 is used to calculate the tilt correction drive amounts a ₁ , a ₂ , and a ₃ of the tilt correction elements 13a, 13b, and 13c, and then according to a command signal from the user. To S600 or S700. In S700, the driving amounts a ₁ , a ₂ , and a ₃ calculated in S500 are presented to the user using the driving amount presenting means 31. The driving amount calculation step of the present invention corresponds to S500, and the presentation step of the present invention corresponds to S700.

The tilt correction drive amounts a ₁ , a ₂ , and a ₃ are calculated using the adaptive matrix A generated in the steps S510 to S560 of FIG.

First, in S510 of FIG. 5, detects a focus reference position _{P 0} in the same manner as S100, and then, at S520, the position of the focus lens 5 is just as imaging patterns TP1~TP4 and S200 to focus (in-focus The positions P1 to P4) are detected, and then the process proceeds to S530.

  Next, in S530, a predetermined drive amount (for example, one rotation) is applied to each of the tilt correction elements 13a, 13b, and 13c, and the amount of change (b) in the in-focus position is detected for each of the imaging patterns TP1 to TP4. To S550.

  Next, in S550, the response matrix generation means 28 is used to generate a response matrix R having the amount of change in focus position with respect to the drive amount for each of the tilt correction elements 13a, 13b, 13c as a component, and then the process proceeds to S560. .

Next, in S560, the inverse matrix (A = R ⁻¹ ) of the response matrix is generated using the adaptive matrix generation means 28.

Then, in S600, based on the tilt correction driving amount _{a 1,} a 2, _{a 3} calculated in S500, the tilt correction device 13a is driven by the driving amount _{a 1,} a perspective correction device 13b by driving amount _{a 2} was driven, the tilt correction element 13c is driven by the driving amount _{a 3,} then it proceeds to S200, until it is determined that the correction required (No) smaller than the displacement amount b is laid value at S400, repeatedly S200~S600 If it is determined in step S400 that correction is not necessary (No), the process proceeds to step S700, where a tilt correction end signal is presented in step S700, and then the main tilt correction procedure ends. The tilt correction step in the present invention corresponds to S600.

  When S200 to S600 are repeated, S510 to S560 are not necessarily repeated, and the adaptive matrix generated in the first processing procedure may be used repeatedly. Moreover, S510-S560 may be implemented before S200-S600, and an adaptive matrix may be provided beforehand.

Next, as shown in FIG. 6, the tilt correction method and tilt correction apparatus 1 of the first embodiment have been verified by the inventors of the present invention. In FIG. 6, (a) is a focus evaluation curve obtained before correction, and (b) is a focus evaluation curve obtained after correction. Before tilt correction, as shown in FIG. 6 (a), the deviation occurs in the in-focus position _(P 0 _{~P 4)} of each imaging pattern, after perspective correction, shown in FIG. 6 (b) As can be seen, the deviation is corrected. As a result, it can be seen that the tilt of the image sensor 8 relative to the optical axis is corrected.

As described above, the tilt correction method and the tilt correction apparatus 1 according to the first embodiment are adjusted so that the focus positions (P _{0 to} P ₄ ) of the focus lens 5 in the plurality of imaging patterns TP0 to TP4 coincide. By calculating the drive amounts of the correction elements 13a, 13b, and 13c, the tilt correction does not require a precise horizontal and vertical drive mechanism for the image sensor 8, and the tilt center of the image sensor is rotated. Even when they do not coincide with the horizontal direction or the vertical direction, the tilt center is not restricted, and high accuracy can be obtained with a relatively simple configuration.

  Further, the tilt correction method and the tilt correction apparatus 1 of the first embodiment generate a response matrix R configured by the amount of change in the focus position with respect to the drive amount for each of the plurality of tilt correction elements 13a, 13b, and 13c. When the response matrix is represented by R, the drive amount is represented by a, and the change amount is represented by b, the drive amount for tilt correction is obtained with high accuracy by calculating the drive amount a so that it is a solution of an equation of Ra = b. be able to.

  Further, the tilt correction method and the tilt correction device 1 of the first embodiment, when any one of the plurality of tilt correction elements (for example, the tilt correction element 13a) is driven, the target tilt correction element is driven. The image sensor 8 can be tilted and tilted with the straight line connecting the two tilt correction elements (tilt correction elements 13b and 13c) facing (13a) as the rotation axis, so that the image sensor 8 is tiltably supported. There is no need to provide a separate rotating shaft, and productivity can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram showing the configuration of the tilt correction device of the imaging apparatus of the second embodiment, FIG. 8A is a layout diagram of tilt elements in the second embodiment, and FIG. It is a figure showing the position of the focus evaluation of the test chart CH in a form. FIG. 9 is a flowchart showing the procedure of the tilt correction method of the image pickup apparatus according to the second embodiment.

  Note that the tilt correction method and tilt correction device of the image pickup apparatus in the second embodiment are basically the same in configuration as those in the first embodiment, and therefore, the same symbols are assigned to components common to the first embodiment. Thus, the detailed description will be omitted and the characteristic points will be described below.

  As illustrated in FIG. 7, the tilt correction apparatus 1 </ b> A according to the second embodiment includes a plurality of imaging patterns TP <b> 0 to TP <b> 4 calculated by the focus detection unit 22 instead of the parameter generation unit 29 according to the first embodiment. There is provided a tilting surface calculating means (so-called tilting surface detecting means of the present invention) 35 that calculates a plane having the smallest difference from the in-focus position as a tilting focus plane. Further, the tilt correction device 1A according to the second embodiment cancels the tilt of the tilt focus surface based on the calculation result by the tilt surface calculation unit 35 instead of the driving amount calculation unit 30 according to the first embodiment. The driving amount calculation means 30A for generating the driving amount of the tilt correction element (reference numerals 13d, 13e, and 13f in FIG. 7A) is provided.

  Further, as shown in FIG. 8, in the second embodiment, the tilt correcting element 13d disposed at the optical center and the tilt correcting element 13d are orthogonal to each other with the tilt correcting element 13d as a base point and are disposed on the x-axis and the y-axis. The tilt correction elements 13e and 13f are connected to the image sensor 8. At this time, the x-axis and the y-axis are orthogonal to the optical axis direction Z.

  In the second embodiment, the tilt correction element 13d is locked in the optical axis direction at the focus reference position detected by the focus reference position detection means 23, and the tilt correction element is used with the tilt correction element 13d as a fulcrum. 13e and 13f are driven and tilt correction is performed.

As shown in FIG. 8B, the tilt surface calculation unit 35 gives the subscript i associated with the imaging patterns TP <b> 0 to TP <b> 4 to the xy coordinate system to indicate the measurement point of the focus evaluation on the chart CH. , The xy coordinates and the optical axis direction using the amount of deviation b in the optical axis direction with respect to the in-focus reference position (in this embodiment, the in-focus position of TP0) of the imaging patterns TP1 to TP4 detected by the focus detection means 22 The three-dimensional coordinates (x _i , y _i , b _i ) are generated.

Then, the tilt plane calculating means 35 sets (= x _i , y _i , b) of all measurement points corresponding to the imaging patterns TP0 to TP4 as represented by (Expression 5) as b = μ ₁ x + μ ₂ y + μ _{3. i} ) With respect to the coordinates, the surface where the error χ ₂ is small is calculated as the in-focus surface.

Further, the aforementioned μ ₁ , μ ₂ , and μ ₃ are calculated using (Equation 6).
Further, the matrix X ⁺ in (Expression 6) is a generalized inverse matrix of the matrix X defined by X ⁺ = (X ^T X) ⁻¹ X ^T , and the matrix X expressed in (Expression 7) Generate from. Here, ^XT is a transposed matrix in which the rows and columns of the matrix X are replaced. In (Expression 7), X _{1 to} X ₄ and Y _{1 to} Y ₄ correspond to the coordinates of the measurement points for focus evaluation corresponding to the imaging patterns TP _{1 to} TP ₄ .

On the other hand, the vector v represented by (Formula 6) is generated as represented by (Formula 8).
In (Expression 8), γ is calculated by an arithmetic expression of γ = α / Β based on the driving amount の of the tilt correction element when the image pickup device is moved by a predetermined amount α along the optical axis direction. In (Equation 8), b _{1 to} b _M are deviation amounts of the focus positions P _{1 to} P ₄ of the focus lens 5 corresponding to the imaging patterns TP 1 to TP 4 with respect to the focus reference position P ₀ of the focus lens 5. is there.

Then, the driving amount calculation unit 30A uses the following equation, when showing the plane perpendicular to the optical axis and the ideal focusing plane Z ₀ at a focus reference position _{P 0, μ 1, μ 2} , μ 3 The difference (Z ₀ −Z) between the focusing plane Z determined in step 1 and the ideal focusing plane Z ₀ is calculated as the drive amount a _j of the tilt correction elements 13e and 13f. At this time, x ′ _j and y ′ _j are coordinates for the tilt correction elements 13e and 13f, and are confirmed in advance.
a _j = μ ₁ x ′ _j + μ ₂ y ′ _j + μ ₃

  Next, the procedure of the tilt correction method according to the second embodiment will be described with reference to FIG. This procedure is executed by the CPU 14 giving a command signal to each function unit based on a program stored in the ROM 16. Further, S in FIG. 9 represents a step.

  First, this procedure starts when a start signal is input to the tilt correction apparatus 1A by the user, erases and initializes the previous calculation result stored in the buffer 34, and then proceeds to S100. .

Next, in S100, the focus evaluation value (MTF) of the imaging pattern TP0 is measured using the focus reference position detection unit 23 while sliding the focus lens 5 in the optical axis direction, and the focus evaluation value reaches a peak. The position (P ₀ ) of the focus lens 5 is detected as a reference position, and then the process proceeds to S200.

Next, in S200, the focus evaluation value corresponding to the slide amount of the focus lens 5 is obtained for each of the imaging patterns TP1 to TP4 while the focus lens 5 is slid in the optical axis direction using the focus position detection unit 24. (So-called focus evaluation value curve is measured), and this is recorded, and the position (P _{1 to} P ₄ ) of the focus lens 5 at which the focus evaluation value peaks is detected as the focus position. .

Then, in S300, by using the deviation amount calculation unit 25, the deviation amount between the position of the focus lens 5 which the imaging pattern TP1~TP4 is focused _(P 1 ~P ₄₎ for focusing the reference position _{(P 0)} (b _{1 to} b ₄ ) are calculated, and then the process proceeds to S400.

Next, in S400, the correction necessity determination unit 26 is used to determine the necessity of correction by comparing the deviation amount (b _{1 to} b ₄ ) with a predetermined threshold value. When the deviation amount is equal to or less than the threshold value. If no correction is necessary, the process proceeds to S700. In S700, the driving amount presenting means 31 is used to present a correction end instruction signal, and the tilt correction processing procedure ends. On the other hand, if the amount of deviation is larger than the threshold value in S400, the correction is necessary and the process proceeds to S410.

  Next, in step S410, the tilting surface calculation unit 35 is used to calculate the tilting focal plane Z according to (Expression 6) to (Expression 8), and then the process proceeds to S420.

  Next, in S420, the coordinates of the tilt correction element and the movement amount γ in the optical axis direction of the image sensor 8 according to the drive amount of the tilt correction element are acquired, and then the process proceeds to S501.

Next, in S501, the drive amount calculation means 30A is used to calculate the drive amount (a _j = μ ₁ x ′ _j + μ ₂ y ′ _j + μ ₃ ) of each tilt correction element 13e, 13f, and then S601. Move on.

  Next, in S601, the CPU 32 rotates the correction elements 13e and 13f by an amount corresponding to the drive amount calculated by the drive amount calculation means 30A using a drive source (not shown), tilts the image sensor 8, and then The process moves to S602. At this time, the imaging element 8 is locked in the optical axis direction by the tilt correction element 13d, and when the tilt correction element 13e is rotationally driven, the straight line connecting the tilt correction element 13d and the tilt correction element 13d. When the tilt correction element 13f is rotationally driven, the image pickup device 8 tilts about the straight line connecting the tilt correction element 13d and the tilt correction element 13e.

Subsequently, in S602, the focus lens 5 is slid in the optical axis direction by using the focus position detection unit 24, and the focus lens 5 is measured for each of the measurement points associated with the imaging patterns TP0 to TP4 of the chart CH. In-focus evaluation value corresponding to the slide amount (so-called in-focus evaluation value curve) is measured and recorded, and at the same time, the position of the focus lens 5 at which the in-focus evaluation value peaks (P ₀ to detecting the P ₄₎ as the in-focus position, then it moves to S603.

Next, in S603, each deviation amount (difference) at each in-focus position (P _{0 to} P ₄ ) detected in S602 is compared with a predetermined threshold value. If the deviation amount is equal to or less than the threshold value, no correction is necessary. Proceeding to S700, in S700, the driving amount presentation means 31 is used to present a correction end instruction signal, and the tilt correction processing procedure ends. On the other hand, if the amount of deviation is larger than the threshold value in S603, the correction is necessary, and the process proceeds to S400, and S400 to S603 are repeated.

As described above, the tilt correction method and tilt correction apparatus 1A of the second embodiment configure a three-dimensional coordinate system including coordinates in the optical axis direction and coordinates in two directions orthogonal to the optical axis and orthogonal to each other. In the three-dimensional coordinate system, using the tilt surface detection means, the plane having the smallest difference from the focus positions of the plurality of imaging patterns detected by the focus position detection means 24 is detected as the tilt focus surface. using the drive amount calculation means, so as to cancel the inclination of the tilt focusing plane Z with respect to the reference focal plane Z ₀ which is perpendicular to the optical axis, the driving amount 13e of perspective correction element, by generating 13f, correcting tilt In this case, a precise driving mechanism in the horizontal and vertical directions with respect to the image sensor 8 is not required, and even when the tilting center of the image sensor 8 does not coincide with the horizontal direction or the vertical direction, the tilt center. Is not limited to the ratio High accuracy can be obtained with a relatively simple configuration.

  As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, It can take various aspects.

For example, in the first and second embodiments, the focus reference position is the position (P ₀ ) of the focus lens 5 at which the measurement point of the imaging pattern TP0 is focused. Instead, the focus reference position is the focus reference position. imaging pattern (TP0~TP0) may be an average position of the positions of the focus lens 5 to focus _(P 0 ~P _4).

  Further, in the first and second embodiments, the in-focus evaluation positions (measurement locations associated with the imaging patterns TP0 to TP4) in the chart CH are not limited to 5 locations, and are corrected by increasing the focus locations. Accuracy can be improved.

  In the second embodiment, the arrangement of the tilt correction elements (13d to 13f) is not limited to three locations, and may be added on the xy axis as necessary.

It is a block diagram showing the structure of the tilt correction apparatus of the imaging device of the 1st Embodiment of this invention. It is a structural diagram of the imaging device of the first embodiment. FIG. 3 is a structural diagram of the imaging device viewed from the direction of an arrow Z in FIG. 2. It is a flowchart showing the procedure of the tilt correction method of the imaging device of the first embodiment. 5 is a flowchart showing a generation procedure of an adaptive matrix in the flowchart of FIG. 4. FIGS. 6A and 6B are diagrams for explaining the effect of tilt correction in the first embodiment, in which FIG. 6A shows a focus evaluation curve before correction and FIG. 6B shows a focus evaluation curve after correction. It is a block showing the structure of the tilt correction apparatus of the imaging device of the 2nd Embodiment of this invention. FIGS. 8A and 8B are explanatory diagrams of a tilt correction element and a test chart according to the second embodiment, in which FIG. 8A shows a layout of the tilt correction element, and FIG. 8B shows a focus evaluation position of the test chart CH. FIG. It is a flowchart showing the procedure of the tilt correction method of the imaging device of the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A ... tilt correction apparatus, 1a, 1b, 1c ... casing, 2 ... front lens, 3 ... zoom lens, 3a ... support member, 3M ... zoom lens drive part, 4 ... light quantity adjustment unit, 4M ... light quantity adjustment drive , 5 ... focus lens, 5a ... support member, 5M ... focus lens drive unit, 5S ... detection unit, 6 ... filter, 7 ... filter spacer, 8 ... image sensor, 9 ... first sensor board, 10 ... support member , 11 ... second sensor board, 12 ... fixing member, 12a ... seat, 13a to 13f ... tilt correction element (small screw), 14 ... circuit board, 14a, 14b, 14c ... biasing member (compression coil spring) 16a, 16b ... connectors, 18a, 18b ... positioning pins, 21 ... field memory, 22 ... focus detection means, 23 ... focus reference position detection means, 24 ... focus position detection Step 25: Deviation amount calculation means 26 ... Correction necessity determination means 27 ... Parameter generation means 28 ... Response matrix generation means 29 ... Adaptive matrix generation means 30, 30A ... Drive amount calculation means 31 ... Drive amount Presentation means, 32... CPU, 33... ROM, 34... Buffer, 35.

Claims (18)

An imaging lens that is slidably installed along the optical axis direction of incident light and guides the subject image to the imaging device, a slide mechanism that slides the imaging lens along the optical axis direction, and the imaging lens. In the imaging apparatus comprising the imaging device that photoelectrically converts the image of the subject image and outputs an image signal,
A plurality of tilt correction elements discretely arranged around the optical axis is connected to the image sensor, and the imaging element is coupled to the optical axis of the incident light by driving the plurality of tilt correction elements. A tilt correction method for correcting the tilt of the image plane,
Image a plurality of imaging patterns discretely arranged on a predetermined chart,
The image pickup lens is slid in the optical axis direction via the slide mechanism, and the optical axis of the image pickup lens is associated with the slide amount for each of the plurality of image pickup patterns imaged on the image pickup device. A focus position detecting step for detecting a focus position in the direction;
A shift amount detection step of detecting a shift amount of the focus position for each of the plurality of imaging patterns detected in the focus position detection step;
A drive amount calculation step of calculating drive amounts of the plurality of tilt correction elements based on the shift amounts detected in the shift amount detection step so that the in-focus positions in the plurality of imaging patterns coincide;
An inclination correction step for correcting the inclination of the image plane based on the drive amount calculated in the drive amount calculation step;
A tilt correction method for an imaging apparatus, comprising: In the in-focus position detecting step, a change curve of a focus evaluation value accompanying a slide in the optical axis direction of the imaging lens is detected, and the imaging lens is moved so as to pass a peak point of the focus evaluation value in the change curve. Sliding in the optical axis direction, and detecting the position of the imaging lens corresponding to the peak point as a focus position;
The tilt correction method for an imaging apparatus according to claim 1. The tilt correction method includes a reference position detection step of detecting a reference position of a focus position of the imaging lens based on an image signal output from the imaging element.
In the shift amount detection step, a shift amount between the reference position and a focus position of the imaging lens for each of the plurality of imaging patterns is detected.
The tilt correction method for an imaging apparatus according to claim 1, wherein the tilt correction method is used. In the driving amount calculating step,
Generating a response matrix composed of a change amount of the in-focus position with respect to a drive amount for each of the plurality of tilt correction elements;
When the response matrix is R, the drive amount is a, and the change amount is b, the drive amount a is a solution of an equation of Ra = b.
The tilt correction method for an imaging apparatus according to any one of claims 1 to 3. When the response matrix R represents the number of the plurality of image pickup patterns as M and the number of the plurality of tilt correction elements as N, the response matrix R includes M rows and N columns. , The amount of change,
The tilt correction method for an imaging apparatus according to claim 4. Using a three-dimensional coordinate system composed of coordinates in the optical axis direction and coordinates in two directions orthogonal to the optical axis and perpendicular to each other,
In the three-dimensional coordinate system, a plane where the difference from the focus position of the plurality of imaging patterns detected in the focus position detection step is the smallest is detected as a focus surface.
Next, when the plane perpendicular to the optical axis is set as a reference focusing surface at a predetermined focusing reference position, the tilt correction element of the tilt correcting element is canceled so as to cancel the inclination of the tilt focusing surface with respect to the reference focusing surface. Generate driving amount,
The tilt correction method for an imaging apparatus according to any one of claims 1 to 3. A presentation step of presenting to the user the drive amounts of the plurality of tilt correction elements calculated in the drive amount calculation step;
The tilt correction method for an imaging apparatus according to any one of claims 1 to 6. In the driving amount calculation step, one of the plurality of tilt correction elements is locked in the optical axis direction, and a driving amount for tilt correction with respect to other tilt correction elements other than the one tilt correction element is calculated. ,
In the tilt correction step, the tilt correction of the imaging plane is corrected by driving other tilt correction elements excluding the one tilt correction element.
The tilt correction method for an imaging apparatus according to any one of claims 1 to 7. When any one of the plurality of tilt correction elements is driven, the image sensor is tilted so that a straight line connecting the two tilt correction elements facing the target tilt correction element is a rotation axis. Let
The tilt correction method for an imaging apparatus according to any one of claims 1 to 7. An imaging lens that is slidably installed along the optical axis direction of incident light and guides the subject image to the imaging device, a slide mechanism that slides the imaging lens along the optical axis direction, and the imaging lens. In the imaging apparatus comprising the imaging device that photoelectrically converts the image of the subject image and outputs an image signal,
A plurality of tilt correction elements discretely arranged around the optical axis is connected to the image sensor, and the imaging element is coupled to the optical axis of the incident light by driving the plurality of tilt correction elements. A tilt correction device for correcting the tilt of the image plane,
Image a plurality of imaging patterns discretely arranged on a predetermined chart,
The image pickup lens is slid in the optical axis direction via the slide mechanism, and the optical axis of the image pickup lens is associated with the slide amount for each of the plurality of image pickup patterns imaged on the image pickup device. A focus position detecting means for detecting a focus position in the direction;
A deviation amount detecting means for detecting a deviation amount of the in-focus position for each of the plurality of imaging patterns detected by the in-focus position detecting means;
Drive amount calculation means for calculating drive amounts of the plurality of tilt correction elements so that the in-focus positions in the plurality of imaging patterns match based on the shift amounts detected by the shift amount detection means;
Inclination correcting means for correcting the inclination of the imaging plane based on the driving amount calculated by the driving amount calculating means;
A tilt correction apparatus for an imaging apparatus, comprising: The in-focus position detecting unit detects a change curve of a focus evaluation value associated with the slide of the image pickup lens in the optical axis direction, and passes the peak of the focus evaluation value in the change curve so that the image pickup lens is passed. It is configured to slide in the optical axis direction and detect the position of the imaging lens corresponding to the peak point as a focus position.
The tilt correction apparatus for an imaging apparatus according to claim 10. The tilt correction device includes a reference position detection unit that detects a reference position of a focus position of the imaging lens based on an image signal output from the imaging element.
The deviation amount detecting means is configured to detect a deviation amount between the reference position and a focus position of the imaging lens for each of the plurality of imaging patterns.
The tilt correction device for an imaging apparatus according to claim 10 or 11, wherein the tilt correction device is used. The driving amount calculating means;
Generating a response matrix composed of a change amount of the in-focus position with respect to a drive amount for each of the plurality of tilt correction elements;
When the response matrix is R, the drive amount is a, and the change amount is b, the drive amount a is a solution of an equation of Ra = b.
The tilt correction apparatus for an imaging apparatus according to any one of claims 10 to 12. When the response matrix R represents the number of the plurality of image pickup patterns as M and the number of the plurality of tilt correction elements as N, the response matrix R includes M rows and N columns. , Configured to be the amount of change,
The tilt correction apparatus for an imaging apparatus according to claim 13. In the tilt correction device,
Constituting a three-dimensional coordinate system composed of coordinates in the optical axis direction and coordinates in two directions orthogonal to the optical axis and perpendicular to each other;
In the three-dimensional coordinate system, there is provided a tilt surface detecting means for detecting a plane having the smallest difference from the focus positions of the plurality of imaging patterns detected by the focus position detecting means as a tilted focus surface. ,
The driving amount calculating means;
When the plane perpendicular to the optical axis at the predetermined focus reference position is the reference focus plane, the drive amount of the tilt correction element is set so as to cancel the tilt of the tilt focus plane with respect to the reference focus plane. Generate,
The tilt correction apparatus for an imaging apparatus according to any one of claims 10 to 12. Providing means for presenting to the user the drive amounts of the plurality of tilt correction elements calculated by the drive amount calculation means;
16. The tilt correction apparatus for an imaging apparatus according to claim 10, wherein the correction apparatus is used. The driving amount calculating means;
One of the plurality of tilt correction elements is locked in the optical axis direction, and is configured to calculate a driving amount for tilt correction with respect to other tilt correction elements excluding the one tilt correction element.
The tilt correction apparatus for an imaging apparatus according to any one of claims 10 to 16. When any one of the plurality of tilt correction elements is driven, the image sensor is tilted so that a straight line connecting the two tilt correction elements facing the target tilt correction element is a rotation axis. Configured to let
18. The tilt correction apparatus for an imaging apparatus according to claim 10, wherein the correction apparatus is used.