JP2001257932A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy in image processing without complicating configuration. SOLUTION: A full focus image pickup device has a high-speed focus control mechanism 10, focus control driving circuit 20 for driving that mechanism, image pickup means 30, microcomputer 40 and liquid crystal display 50. The high-speed focus control mechanism 10 is provided with a variable focus lens 11 capable of varying a focal position corresponding to an observation object and a piezoelectric actuator 12 for changing that focal position. The focal position of the variable focus lens 11 is detected by a sensor 25. Among plural image signals, the most focused image signal is decided for each pixel by a CPU 42 inside the microcomputer 40, one full focus image is generated, and three-dimensional map data are generated on the basis of distance information to the observation object. At such a time, concerning image data stored in an image memory 41, the CPU 42 corrects the magnification change or optical aberration of image caused by an optical image pickup system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of imaging devices such as an optical microscope, an electron microscope, an optical telescope, and an electronic camera, and more particularly to an imaging device for improving a focusing technique.

[0002]

2. Description of the Related Art As a prior art of this kind, there is known a "camera device" disclosed in Japanese Patent Application Laid-Open No. 9-230252 filed by the present applicant. A technique for obtaining an image with a large depth of field has been disclosed. This camera device displays an image in real time while reciprocating a focal position (a distance from a lens to a focal plane, also referred to as a focal length in this specification) with respect to an observation target at a high speed, and has a sharp focused outline. The fact that only a portion is visually recognized as a retinal afterimage is used. This technology makes it possible for an observer to view an image that is in focus over the entire observation target in real time by using the physiological afterimage phenomenon cleverly. It was the preferred imaging technique.

The applicant of the present application has proposed, as an “omnifocal imaging device” to which the above-mentioned camera device technology is applied, as disclosed in Japanese Patent Application No.
No. 300467 has been filed. This Japanese Patent Application No. 11-30
No. 0467 proposes a technique for obtaining a complete omnifocal image in which all the portions to be observed are focused in real time or near real time by using an image processing technique. In particular, the device eliminates the previous problem of blurred images that are out of focus on the retina, which makes it impossible to obtain a perfect omnifocal image and makes the image appear somewhat blurry. I was trying to do it.

[0004]

However, when the focal length is changed by changing the optical characteristics of the imaging lens or the like, including the case of using the variable focus lens disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-230252. Since the magnification of the object and the image on the image sensor changes depending on the focal length, there is a problem that the same point on the observation object is not located at the same coordinate of the image data output from the image sensor. Further, there is a problem that an image is curved due to occurrence of aberration due to a change in optical characteristics. In order to improve the accuracy of an all-focus image or a three-dimensional map, a telecentric lens system whose magnification does not change with the focal length is required. However, this telecentric lens is very large and expensive. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an imaging apparatus capable of improving the accuracy of image processing without complicating the configuration. It is to be.

[0006]

According to the first aspect of the present invention, the variable focus lens has a variable focus position with respect to an observation target, and the focus position is changed at a high speed by an actuator. The imaging unit outputs a real image formed through the variable focus lens as an image signal for each pixel. At this time, image signals for a plurality of images obtained by the imaging means with the change of the focal position are stored in the image memory. The image processing means determines, for each pixel, the most in-focus one of the plurality of image signals, and determines one all-in-focus image in which each part of the observation target is in focus, and the three-dimensional shape of the observation target. At least one of the one three-dimensional numerical model shown is generated. The detecting means detects the focal position of the variable focus lens changed by the actuator, and the correcting means individually corrects the plurality of image signals based on the detected focal position of the variable focus lens.

[0007] In short, in the variable focus lens in which the focal position is variable as described above, there is a problem that the coordinates of the same point are shifted when the magnification is changed, or the image is curved due to the optical aberration. Since the image signal is appropriately corrected based on the focal position of the varifocal lens, various problems due to a change in magnification and optical aberration (distortion) are eliminated. Also, in this case, there is no need for a large and expensive telecentric lens. As a result, the accuracy of image processing can be improved without complicating the configuration.

The correction of the image signal by the correction means is as follows. The image signal is corrected by multiplying the coordinates of each pixel of the image signal by the reciprocal of the magnification of the varifocal lens. As described in the third aspect, the aberration accompanying the change in the optical characteristics of the variable focus lens is quantified in advance, and the image signal is corrected based on the quantified data. It is good to use such a method. According to each of the above-described correction methods, the image signal is subjected to coordinate conversion according to the focal position of the variable focus lens, and an image signal free from a change in magnification or an influence of optical aberration can be obtained.

In a preferred embodiment of the present invention, the varifocal lens and the actuator may be configured as described in claim 4. That is, the varifocal lens is a liquid ring lens having a transparent elastic film whose curvature is variable by the pressure difference between the front and back sides, and a transparent liquid is sealed in an internal space formed by the transparent elastic film, while the actuator is And a piezoelectric actuator that is integrated with the varifocal lens and applies pressure to the transparent liquid when a drive voltage is applied. In such cases,
Since a plurality of image signals having different focal positions can be obtained at high speed, it is very effective when capturing images of an observation target having different focal positions at high speed.

In the above-mentioned invention, the description has been given of the effect that the focus position of the varifocal lens is detected by the detection means and the image signal is corrected based on the detection result (focal position).
The invention according to claims 5 to 7 can be considered as a more specific configuration. That is, in the invention of claim 5, the detecting means is a voltage sensor for measuring a driving voltage applied to the actuator, and the correcting means corrects the image signal based on the measurement value of the voltage sensor. In the invention according to claim 6, the detecting means is a charge amount sensor for measuring the amount of charge injected and the amount of discharge of the actuator, and the correcting means corrects the image signal based on the measured value of the charge amount sensor. In the invention of claim 7, the detecting means is a displacement sensor for directly measuring the displacement amount of the actuator, and the correcting means is
The image signal is corrected based on the measured value of the displacement sensor.

In any case, the focal position of the varifocal lens can be detected in accordance with the driving state of the actuator, and image processing can be performed with high accuracy by correction based on the detection result.

Further, in the invention according to claim 8, the image processing means includes a logic for taking in a plurality of image signals having different focal positions from an image pickup means and a focal position of a varifocal lens based on the logic. Logic for individually correcting a plurality of image signals, extracting a focused pixel from the corrected image signal, and calculating distance information from the image signal where the pixel exists to the observation target. , Logic for reconstructing all-focus image data from the extracted in-focus pixels, and logic for generating a three-dimensional numerical model from the calculated distance information.

According to this configuration, by realizing each logic, it is possible to generate an omnifocal image and a three-dimensional numerical model free from the influence of the change in magnification of the variable focus lens and the optical aberration, thereby realizing a highly practical imaging apparatus. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present embodiment, the invention is embodied in an all-focus image pickup apparatus. In this image pickup apparatus, a plurality of image signals having different focal positions are taken in and the plurality of image signals are appropriately synthesized. Then, an omnifocal image in which the entire image display range is in focus is generated. In addition, the imaging apparatus generates three-dimensional map data (a three-dimensional numerical model) of the observation target based on the plurality of image signals and information on the distance to the observation target. Hereinafter, the details will be described with reference to the drawings.

FIG. 1 shows the overall configuration of an all-focus image pickup apparatus according to the present embodiment. In FIG. 1, the omnifocal imaging device includes a high-speed focus adjustment mechanism 10, a focus adjustment drive circuit 20 for driving the same, an imaging unit 30, a microcomputer (microcomputer) 40, and a liquid crystal display 50 as a display device. Have.

The main components of the high-speed focus adjusting mechanism 10 are a varifocal lens 11 whose focal position with respect to the observation target is variable, and a plurality of varifocal lenses which change the focal position of the varifocal lens 11 (position of the focal plane F). Piezoelectric actuator 1
2 and a fixed lens 13 which are assembled together.

Here, the varifocal lens 11 has a pair of transparent elastic films 11a and 11 whose curvatures are variable by the pressure difference between the front and back sides.
b is a liquid-sealed lens in which a transparent liquid is sealed in an internal space 11c between the transparent elastic films 11a and 11b.
Further, the piezoelectric actuator 12 is provided with the transparent elastic film 11.
A plurality of piezoelectric elements (bimorph elements) 12a are arranged at equal intervals on the periphery of the element a. The outer peripheral portions of the plurality of piezoelectric elements 12a are fixed to the case 12b, and the central portions are fixed to the output shaft 12c. When the plurality of piezoelectric actuators 12 are simultaneously driven and the output shaft 12c reciprocates, the curvature of the transparent elastic films 11a and 11b changes due to a change in the pressure of the transparent liquid, and the focal position (magnification) of the varifocal lens 11 changes. .

This varifocal lens 11 can change the focal position at high speed by changing the lens shape.
This is very effective when capturing images of observation objects having different focus positions at high speed. The configuration of the high-speed focus adjustment mechanism 10 is also described in detail in the above-mentioned Japanese Patent Application Laid-Open No. 9-230252, and the configuration can be applied in the present embodiment.

The focus adjustment drive circuit 20 applies an appropriate voltage to the piezoelectric actuator 12 to
2a is displaced, and all the piezoelectric actuators 12 are driven synchronously. When the piezoelectric actuator 12 is driven by the focus adjustment drive circuit 20, the focal position of the varifocal lens 11 changes according to the driving state of the piezoelectric actuator 12. The focus position of the varifocal lens 11 is the sensor 2
5 is detected. The drive cycle of the piezoelectric actuator 12, that is, the cycle in which the focal position of the variable focus lens 11 changes, may be a cycle in which an all-focus image or a three-dimensional map is obtained in real time.
In an apparatus for generating one omnifocal image, the piezoelectric actuator 12 is driven at high speed so that a desired number of image signals having different focal positions can be obtained within 1/30 second.
In practice, the piezoelectric actuator 12 is driven at a frequency of several hundreds of Hz, and at this time, the focal position is several microseconds to
It is changed little by little every several tens of microseconds.

The sensor 25 may have any configuration as long as it can detect the focal position of the varifocal lens 11. In this embodiment, any one of the following configurations (1) to (3) is employed. That is, (1) a voltage sensor is provided as the sensor 25. In this case, the focus adjustment drive circuit 20 sends the piezoelectric actuator 12
By measuring the voltage applied to the
The focus position of the varifocal lens 11 is detected. (2) A charge amount sensor is provided as the sensor 25. In this case, the focus position of the varifocal lens 11 is detected by measuring the charge injection amount and the discharge amount of the piezoelectric actuator 12 with a charge amount sensor. (3) A displacement sensor is provided as the sensor 25. In this case, the focal position of the varifocal lens 11 is detected by directly measuring the amount of displacement of the piezoelectric actuator 12 with a displacement sensor. The configuration (3) for directly measuring the actuator displacement is described in detail in Japanese Patent Application No. 10-246198 filed by the present applicant. A detection unit is incorporated to detect the amount of distortion (bending amount) when the actuator is driven, and convert the amount of distortion to a displacement amount.

In short, the focal position of the varifocal lens 11 is determined by the lens shape of the lens 11, and the lens shape is determined by the displacement of the piezoelectric actuator 12. Since the sensors (1) to (3) all measure the lens shape indirectly or directly, the focal position of the varifocal lens 11 can be detected by the measurement.

Incidentally, the voltage sensor of the above (1) has an advantage that it is inexpensive. Further, the charge amount sensor of (2) and the displacement sensor of (3) have an advantage that the displacement amount of the piezoelectric actuator 12 can be accurately detected, and the accuracy in the depth direction when constructing a three-dimensional map is improved. That is, in this case, comparing the sensors (1) to (3), the cost is reduced in the order of (3) → (2) → (1), but the cost is reduced in the order of (1) → (2) → (3). The detection accuracy of the focal position (actuator displacement amount) increases in order.

The image pickup means 30 comprises a solid-state image pickup device 31 and an image pickup device drive circuit 32.
Has the function of outputting an image formed through the device as an image signal for each pixel. The image plane of the solid-state imaging device 31 is fixed to a position where the observation target forms an image with respect to the high-speed focus adjustment mechanism 10 through the variable focus lens 11 and the fixed lens 13. As the solid-state imaging device 31, a CCD image sensor, a CMOS image sensor, a CMD image sensor, or the like is used. In particular, if a high-speed drive type image sensor that can output image data at a video rate or higher is used,
An omnifocal image and a three-dimensional map can be generated in a short time that allows real-time display.

The microcomputer 40 comprises: an image memory 41 capable of storing image signals from the image pickup means 30 over a plurality of image signals;
It includes a CPU 42 that performs image processing based on the image signals of the plurality of sheets and controls the entire omnifocal imaging device. The image memory 41 is a frame memory, and can collectively input and output image signals one by one at a high speed.

The CPU 42 includes a focus adjustment drive circuit 20, an image pickup means 30, an image memory 41, and a liquid crystal display 50.
It has a function to control by properly synchronizing. Also, CPU
Reference numeral 42 controls the driving of the piezoelectric actuator 12 via the focus adjustment drive circuit 20, and determines and extracts, for each pixel, the most in-focus image signal among a plurality of image signals obtained at that time. In addition to generating all omnifocal images, three-dimensional map data (three-dimensional three-dimensional numerical model) is generated based on planar position information of each pixel and information on the distance to the observation target where the pixel exists.

The liquid crystal display 50 is a display device for displaying image data.
Display the three-dimensional map and omnifocal image provided by.

FIG. 2 is a block diagram showing the omnifocal image pickup device by function, and each function will be described with reference to FIG. In particular, the configuration of the image processing unit realized by the CPU 42 in the microcomputer 40 will be described in detail.

In the image processing section, image data picked up by the solid-state image pickup device 31 of the image pickup optical system is fetched by the image data fetching logic section 43. At this time, the image data capturing logic unit 43
, A control signal for sequentially changing the focal position is output, and the image data is sequentially stored in the image memory 41 while corresponding to the focal position for each image data based on the focal position information input from the sensor 25. . That is, the image data capturing logic unit 43 captures a plurality of image data having different focal positions in synchronization with the focus adjustment driving circuit 20.

The image data correction logic unit 44 corrects a change in magnification of an image or an optical aberration caused by the imaging optical system with respect to the image data fetched and stored in the image memory 41 as described above, and The image data is stored in the image memory 41 again. However, details of the image data correction will be described later.

The all-focus calculation logic unit 45 uses a large number of image data stored in the image memory 41,
A focused pixel is extracted from a plurality of image data (corrected image data) having different focal positions, and distance information to the observation target is calculated from the image data in which the pixel exists. At this time, the logic unit 45 determines the focal point based on the correlation between the luminance value and the focal position of each pixel. This focus determination will be described later.
The calculation of the distance information may be performed with reference to the focal position information of the image data.

The three-dimensional map generation logic unit 46 generates three-dimensional map data as a three-dimensional numerical model of the observation target based on information on the distance to the observation target. For example, processing such as expressing three-dimensional information by contour lines is performed. Then, the three-dimensional map data is displayed on the display device (the liquid crystal display 50).

The image data reconstruction logic unit 47
When the all-focus calculation logic unit 45 completes the in-focus determination for all pixels, it reconstructs a single all-focus image (an image in which all parts of the observation target are focused). Then, the omnifocal image is displayed on the display device (the liquid crystal display 50).

Next, correction relating to a change in magnification as correction content in the image data correction logic unit 44 will be described with reference to FIG. FIG. 3 shows how the magnification of the image changes when the focal length to the observation target is changed. 3A, 3B, and 3C show the cases where the focal length is long, intermediate, and short, respectively. Of these, (a) is a low magnification based on (b), and (c) is It is assumed that the magnification is high.

That is, as shown in FIG. 3A, when the focal length becomes longer, the magnification becomes lower, and conversely, as shown in FIG.
When the focal length is shortened as in the above, the magnification increases. In this case, the image data correction logic unit 44 recognizes the magnification of the varifocal lens 11 based on the focal position information obtained from the sensor 25 and stores the reciprocal of the magnification of the varifocal lens 11 in the coordinates of each pixel of the image data. To correct the image data. As a result, the image data is corrected according to the magnification at which the observation target is formed on the solid-state imaging device 31, and the observation target is always obtained as the image data at the same magnification.

Further, it is considered that the imaging optical system (variable focus lens 11) of the present imaging apparatus causes optical aberration as shown in FIG. Therefore, the image data correction logic unit 44
Then, the optical aberration generated by the imaging optical system is quantified in advance based on parameters such as the focal position, and the image data is corrected based on the quantified data. That is, in the correction, the coordinates of each pixel are converted so that the optical aberration caused by the change in the focal position of the variable focus lens 11 is reduced. FIG. 4 shows a state in which the image data is distorted due to the optical aberration when the image data is acquired through the imaging optical system, and thereafter, the distortion is eliminated by the correction in the image data correction logic unit 44.

Next, a method of extracting a focused pixel in the all-focus calculation logic unit 45 will be described. The apparatus according to the present embodiment uses an all-focus determination algorithm that compares a change in the luminance value of the same pixel between two or more image frames. In addition,
The details are described in the aforementioned Japanese Patent Application No. 11-300467.

In short, when a black-and-white pattern on an object to be observed is photographed, extreme values (maximum value and minimum value) of the luminance value of the pixel near the boundary between white and black are changed with the change of the focal position.
Appears. Therefore, the maximum value and the minimum value of the luminance value of the pixel at the same xy coordinate are extracted, and the first derivative value of the luminance value at that position is obtained to detect the extreme value and determine the focus position. I do. However, since the correlation between the focal position and the extreme value of the luminance value is unclear in the pixels near the boundary, in the present embodiment, the maximum luminance value is determined as the focal position.

The algorithm of the in-focus determination will be briefly described with reference to the flowchart of FIG.
The luminance values of pixels at the same coordinates are sampled from a plurality of images having different focus positions stored in the image data (step S1). Next, the minimum value (Min) and the maximum value (Max) of the luminance value are extracted (step S2), and thereafter, the sign of the difference value of the luminance value is inverted between the focal position of the maximum value and the focal position of the minimum value. It is determined whether or not it has been performed (step S3).

When the difference value of the luminance value is inverted between the positive value and the negative value in only one of the maximum value and the minimum value, it can be determined that only one of the positive peak and the negative peak is formed.
Therefore, the A determination is made, and the focal position where the peak of the luminance value is formed is set as the focal point (step S4).

On the other hand, when the difference between the luminance values is inverted at both the maximum value and the minimum value, it can be determined that both the positive peak and the negative peak are formed. Therefore, the B determination is made, the negative peak is excluded, and the focal position where the luminance value forms a positive peak is set as the focal point (step S5). In step S5, the positive peak may be excluded, that is, it is determined that one of the positive and negative peaks has the in-focus position.

As shown in FIG. 6, when the simple determination is made, as shown in FIG. 6, when the B determination that there are both positive and negative peaks is made, the in-focus point is erroneously determined (denoted as NG in the figure). ). However, according to a viewpoint obtained by repeated experiments by the inventors, even when an erroneous determination is made in the in-focus determination, in many cases the in-focus position is close to the in-focus position, and a large error does not occur.

According to this embodiment described in detail above, the following effects can be obtained. (A) Since the focus position of the varifocal lens 11 is detected and the image signal is corrected based on the detection result, the coordinates of pixels at the same point are shifted when the magnification is changed, or the image is curved due to optical aberration. Conventional problems are solved. Also, in this case, there is no need for a large and expensive telecentric lens. As a result, the accuracy of image processing can be improved without complicating the configuration. In particular, in the apparatus of the present embodiment, a high-precision omnifocal image and a three-dimensional map can be simultaneously generated. Thus, an omnifocal image can be obtained with high accuracy in an optical system having a shallow depth of field such as a microscope. In addition, since the distance and the shape to the observation target can be recognized, it can be applied to a robot vision and the like.

(B) The correction contents of the image signal are as follows: The image signal is corrected by multiplying the reciprocal of the magnification of the varifocal lens 11. The image signal is corrected based on optical aberration data quantified in advance. The varifocal lens 11
The image signal is coordinate-transformed according to the focal position of the image, and an image signal free from the influence of magnification change and optical aberration can be obtained.

(C) By using the high-speed focus adjustment mechanism 10 in which the variable focus lens 11 and the piezoelectric actuator 12 are integrated, a plurality of image signals having different focus positions can be obtained at high speed.

(D) Since any one of a voltage sensor, a charge sensor, and a displacement sensor is used as the sensor 25 for detecting the focal position of the variable focus lens 11, the variable focus is changed according to the driving state of the piezoelectric actuator 12. The focal position of the lens 11 can be properly detected, and image processing can be accurately performed by correction based on the detection result. It should be noted that which sensor to use may be determined from the viewpoint of cost in constructing the present imaging device or the viewpoint of required accuracy.

(E) For image data groups obtained at a plurality of focal positions, the focal position is determined based on luminance data of one pixel at the same xy coordinate. That is, a change in luminance was observed for each pixel alone without omitting the correlation with the surrounding pixels.
As a result, the calculation load required for the determination of the focused pixel is extremely reduced, and the focus position can be determined at a high speed. Therefore, the real-time property of image display is improved.

The present invention can be embodied in the following forms other than the above. In the above-described embodiment, the focus position of the varifocal lens 11 is detected from the sensor detection value using the sensor 25 including any one of the voltage sensor, the charge amount sensor, and the displacement sensor. However, the configuration is changed. For example, the pressure in the internal space 11c of the varifocal lens 11 (the pressure of the transparent liquid) may be measured by a pressure sensor, and the focal position of the varifocal lens 11 may be detected from the measured value. Alternatively, the focus adjustment drive circuit 20 may read a drive signal input to the piezoelectric actuator 12 in the CPU 42 and detect (calculate) the focus position of the varifocal lens 11 accordingly. In this case, the pressure sensor or the CPU 42 corresponds to the detecting unit.

The variable focus lens is not limited to the liquid ring lens having the pair of transparent elastic films 11a and 11b as described above. Further, the actuator is not limited to the above configuration. In any case, the present invention can be applied to any configuration using a variable focus lens whose focal position with respect to the observation target is variable and an actuator capable of changing the focal position at high speed.

In the above embodiment, both the omnifocal image and the three-dimensional map data (three-dimensional numerical model) are generated and displayed on the display device. The present invention may be embodied as an imaging device that generates and displays only one of map data (a three-dimensional numerical model).

As another judging method different from the above-mentioned in-focus point judging method, a captured image signal is divided into a line-shaped or area-shaped minute area, and a contrast value for the same minute area is determined between two or more image frames. A method of comparing and selecting the pixel data having the maximum contrast value is also possible. The contrast value of the minute area can be converted into a contrast value by a method generally used conventionally, for example, a luminance value of image data is converted into a luminance dispersion method, a luminance amplitude method, an entropy method, a DCT method, or a method combining them. It can be obtained by conversion.

On the other hand, as a method for improving the accuracy of the three-dimensional map, a noise removal filter for removing high-frequency components is inserted between the all-focus calculation logic part 45 and the three-dimensional map generation logic part 46 in FIG. You may. As a form of the noise elimination filter, noise is likely to occur in a portion where the contrast changes abruptly, such as the end of the observation object. Therefore, the three-dimensional map data of the all-focus calculation logic unit 45 is converted into a spatial frequency component, It is effective to remove only high-frequency components containing a large amount of, and then return to three-dimensional map data again. The method of converting the three-dimensional map data in the time domain into data in the spatial frequency domain may be any of the discrete cosine transform method, the Fourier transform method, and the discrete sine transform method.

Another configuration of the noise removal filter is as follows.
By taking “moving average” or “total average” for the three-dimensional map data output from the all-focus calculation logic unit 45, a filter for removing high-frequency components containing much noise, and the output from the all-focus calculation logic unit 45 3D map data to be divided into line-shaped or area-shaped minute areas,
It is also possible to use a “majority decision” filter that removes noise by replacing all three-dimensional map data in each minute region with the three-dimensional map data that occurs most frequently in the minute region.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an outline of an all-focus imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an omnifocal imaging device for each function.

FIG. 3 is a diagram illustrating correction of a change in magnification of an imaging optical system.

FIG. 4 is a diagram illustrating correction of optical aberration of an imaging optical system.

FIG. 5 is a flowchart showing an algorithm of focus determination.

FIG. 6 is a list showing the results of focus determination.

[Explanation of symbols]

10: High-speed focus adjustment mechanism, 11: Variable focus lens, 11
a, 11b: transparent elastic film, 11c: internal space, 12: piezoelectric actuator, 20: focus adjustment drive circuit, 25: sensor, 30: imaging means, 40: microcomputer, 41: image memory, 42: image processing means and correction CP as a means
U.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/262 H04N 13/02 13/02 G02B 7/11 DF term (Reference) 2H051 BA41 FA07 FA09 FA60 5C022 AA01 AA13 AB44 AB68 AC03 AC42 AC54 AC69 5C023 AA02 AA10 AA11 AA37 AA38 BA11 5C061 AB02 AB06 AB17

Claims (8)

[Claims] A variable focus lens having a variable focus position with respect to an observation target; an actuator for changing the focus position of the variable focus lens at high speed; and a real image formed through the variable focus lens output as an image signal for each pixel. An image memory that can store a plurality of image signals obtained in accordance with a change in the focal position; and determining the most in-focus one of the plurality of image signals for each pixel. An imaging apparatus comprising: an all-in-focus image focused on each part of an observation target; and a three-dimensional numerical model indicating a three-dimensional shape of the observation target; and an image processing unit configured to generate at least one of the three-dimensional numerical model. Detecting means for detecting the focal position of the variable focus lens changed by the actuator; and Imaging apparatus characterized by comprising a correction means for correcting the image signal individually. 2. The image pickup apparatus according to claim 1, wherein said correction means corrects the image signal by multiplying a coordinate of each pixel of the image signal by a reciprocal of a magnification of a variable focus lens. 3. The method according to claim 1, wherein the correcting means quantifies in advance aberrations caused by changes in optical characteristics of the variable focus lens, and corrects an image signal based on the quantified data.
An imaging device according to claim 1. 4. The varifocal lens is a liquid ring lens having a transparent elastic film whose curvature is variable by the pressure difference between the front and back, and a transparent liquid sealed in an internal space formed by the transparent elastic film. On the other hand, the actuator is a piezoelectric actuator that is integrated with a varifocal lens and applies pressure to the transparent liquid with application of a drive voltage.
3. The imaging device according to any one of 3. 5. The imaging apparatus according to claim 4, wherein said detecting means is a voltage sensor for measuring a driving voltage applied to said actuator, and said correcting means is configured to generate an image based on a value measured by the voltage sensor. An imaging device that corrects a signal. 6. The image pickup apparatus according to claim 4, wherein said detecting means is a charge amount sensor for measuring an amount of charge injection and discharge of said actuator, and said correction means is a measurement value of said charge amount sensor. An image pickup device that corrects an image signal based on the image signal. 7. The imaging apparatus according to claim 4, wherein said detecting means is a displacement sensor for directly measuring a displacement amount of said actuator, and said correcting means outputs an image signal based on a measured value of said displacement sensor. An imaging device to be corrected. 8. The image processing means comprises: logic for taking in image signals of a plurality of images having different focal positions from an image pickup means; and individually correcting the plurality of image signals based on a focal position of a varifocal lens. Logic for extracting a focused pixel from the corrected image signal, and calculating distance information to an observation target from an image signal in which the pixel exists, and logic for calculating the distance of the extracted focus. The imaging apparatus according to claim 1, further comprising: logic for reconstructing omnifocal image data from matching pixels; and logic for generating a three-dimensional numerical model from the calculated distance information.