JP2000152064A - Automatic focus controller - Google Patents

Automatic focus controller

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Publication number
JP2000152064A
JP2000152064A JP10325345A JP32534598A JP2000152064A JP 2000152064 A JP2000152064 A JP 2000152064A JP 10325345 A JP10325345 A JP 10325345A JP 32534598 A JP32534598 A JP 32534598A JP 2000152064 A JP2000152064 A JP 2000152064A
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Japan
Prior art keywords
position
focus
image
image data
calculated
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Pending
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JP10325345A
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Japanese (ja)
Inventor
Masaru Oikawa
賢 及川
Original Assignee
Ricoh Co Ltd
株式会社リコー
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Application filed by Ricoh Co Ltd, 株式会社リコー filed Critical Ricoh Co Ltd
Priority to JP10325345A priority Critical patent/JP2000152064A/en
Publication of JP2000152064A publication Critical patent/JP2000152064A/en
Pending legal-status Critical Current

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Abstract

(57) [Problem] To provide an automatic focus control device capable of performing a high-speed and high-accuracy focusing operation. An automatic focus control device shown in FIG. 1 performs image restoration on image data obtained by imaging at an initial focus lens position using a plurality of restoration filters corresponding to a first point image radius. Then, an AF evaluation value is calculated for the image data group restored for each restoration filter, and the calculated AF evaluation value is collated to determine a rough focus position. The image data obtained by imaging while moving the image is subjected to image restoration using a restoration filter corresponding to an arbitrary point image radius to calculate an AF evaluation value, and the calculated AF evaluation value is used as a focus lens. The final in-focus position is determined by referring to each drive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic focus control device, and more particularly, to an automatic focus control device applied to an image input device using an image pickup device such as a video camera and a still video camera.

[0002]

2. Description of the Related Art Conventionally, a focus position determination method in an automatic focus control device has been based on active A using infrared rays or ultrasonic waves.
F type, passive A for external light passive, hill climbing servo etc.
There is the F method. In particular, in a digital still video camera (hereinafter abbreviated as "DSVC") and the like, a passive AF method that does not require a special distance measuring component is often used.
In the passive AF system, as a device for detecting a focus position in one shot in recent years, there is Japanese Patent Application Laid-Open No. 6-181532, "a focus position detection device for an electronic camera". Such a focus position detection device uses a one-shot AF,
That is, the focus position is detected by one shot using the restoration filter.

More specifically, the in-focus position detecting apparatus obtains a plurality of points of a point spread function of an optical image pickup system or a function obtained by converting the point spread function from a focus position and lens positions before and after the focus position and stores the same. Characteristic value storing means, image restoring means for restoring image data for one screen or a part thereof for each of the plurality of lens positions by using characteristic values stored in the characteristic value storing means, and image restoring means. Focus position estimating means for obtaining an evaluation value of the in-focus position for each lens position from the image data obtained and comparing each evaluation value to estimate the in-focus position. , It is possible to do more accurately.

[0004]

However, in the above-described conventional one-shot AF using the restoration filter,
There is a problem that it is difficult to prepare a large number of restoration filters due to the limitation of the capacity of a mounted memory (ROM) or the like, and it is difficult to perform a focusing operation with high accuracy. In addition, when a large number of restoration filters are used, the amount of calculation at the time of restoring the image increases, and there is a problem that it is difficult to perform a high-speed focusing operation.

[0005] The present invention has been made in view of the above problems, and has as its object to provide an automatic focus control device capable of performing a high-speed and high-accuracy focusing operation.

[0006]

In order to solve the above-mentioned problems, an automatic focus control device according to the present invention provides an auto-focus control apparatus for image data obtained by imaging at an initial focus lens position.
Image restoration is performed using a plurality of restoration filters corresponding to the point image radius, an AF evaluation value is calculated for an image data group restored for each restoration filter, and the calculated AF evaluation values are collated to obtain a general synthesis result. The focus position is determined, and then image restoration is performed on image data obtained by moving the focus lens from the approximate focus position using a restoration filter corresponding to an arbitrary point image radius. Then, the AF evaluation value is calculated, and the final AF position is determined by referring to the calculated AF evaluation value every time the focus lens is driven.

According to a second aspect of the present invention, in the automatic focus control apparatus according to the first aspect, the AF evaluation value is determined by a ratio between a negative value integrated value and a high frequency component integrated value in an AF area. It is to be calculated.

According to a third aspect of the present invention, in the automatic focus control device according to the first or second aspect, the arbitrary point image radius is set to 5 or less.

According to a fourth aspect of the present invention, there is provided an automatic focus control device which picks up an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing image data restoration, and compares the calculated AF evaluation values to determine an in-focus position, A lens, a table storing position information for driving the focus lens corresponding to the zoom lens position, a zoom lens position detection unit for detecting the zoom lens position, and a zoom detected by the zoom lens position detection unit Based on the lens position, referring to the table,
Focusing lens driving means for driving the focusing lens to a focusing position.

According to a fifth aspect of the present invention, there is provided an automatic focus control device, which picks up an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing image data restoration, and compares the calculated AF evaluation values to determine an in-focus position, A lens, a zoom lens position detection unit that detects the zoom lens position, and an imaging condition control unit that controls imaging conditions during a focusing operation based on the zoom lens position detected by the zoom lens position detection unit. It is provided.

According to a sixth aspect of the present invention, there is provided an automatic focus control apparatus according to any one of the first to third aspects, wherein the zoom lens and the focus lens correspond to the zoom lens position. A table storing position information for driving the zoom lens position detecting means for detecting the zoom lens position, based on the zoom lens position detected by the zoom lens position detecting means, with reference to the table, Focusing lens driving means for driving the focusing lens to a focusing position.

According to a seventh aspect of the present invention, in the automatic focus control device according to any one of the first to third aspects, a zoom lens and a zoom lens position for detecting a zoom lens position are provided. A detecting means; and an imaging condition control means for controlling an imaging condition at the time of a focusing operation based on the zoom lens position detected by the zoom lens position detecting means.

The automatic focus control device according to claim 8 is provided with at least two initial focus lens positions, picks up an image at each initial focus lens position and outputs image data, The image data is restored using a plurality of restoration filters corresponding to the image radii, the AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are compared. A focus position is calculated for each of the initial focus lens positions, and a final focus position is determined based on the focus position calculated for each of the initial focus lens positions.

According to a ninth aspect of the present invention, in the automatic focus control device according to the eighth aspect, at least one of the initial focus lens positions is set to an infinity position or a closest position. .

According to a tenth aspect of the present invention, in the automatic focus control device according to the eighth aspect, the focus positions calculated for each of the initial focus lens positions are weighted and averaged to obtain the final focus position. This is for determining an in-focus position.

The automatic focus control device according to claim 11 is the automatic focus control device according to claim 9, wherein
Is set to the infinity position, the second initial focus lens position is set to the closest position, the image is output at the first initial focus lens position, and image data is output. The image data is restored using a plurality of restoration filters corresponding to the point image radius, and the AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are compared. Calculating a first in-focus position, and if the calculated first in-focus position is a long distance, determines the first in-focus position as a final in-focus position; When the in-focus position is at a short distance, the image is taken at the second initial focus lens position and image data is output, and a plurality of restoration filters corresponding to the point image radius are applied to the image data. To restore image data using An AF evaluation value is calculated for each image data group restored for each restoration filter, and the calculated AF evaluation values are collated to calculate a second focus position, and the first and second focus positions are calculated. Is used to determine the final focus position.

According to a twelfth aspect of the present invention, there is provided an automatic focus control apparatus according to the ninth aspect, wherein
The first initial focus lens position is set to the closest position, the second initial focus lens position is set to infinity position, image data is output at the first initial focus lens position, and image data is output. The image data is restored using a plurality of restoration filters corresponding to the point image radius, and the AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are compared. Calculating a first in-focus position, and when the calculated first in-focus position is a short distance, determines the first in-focus position as a final in-focus position; If the in-focus position is a long distance, the image is taken at the second initial focus lens position and image data is output, and a plurality of restoration filters corresponding to the point image radius are applied to the image data. To restore image data using An AF evaluation value is calculated for each image data group restored for each restoration filter, and the calculated AF evaluation values are collated to calculate a second focus position, and the first and second focus positions are calculated. Is used to determine the final focus position.

According to a thirteenth aspect of the present invention, in the automatic focus control device according to the eleventh or twelfth aspect, a point of a restoration filter group used for image restoration at the second initial focus lens position. The range step and the applicable range of the image radius are smaller than the range step and the applicable range of the point image radius of the restoration filter group used for image restoration in the first initial focus lens.

According to a fourteenth aspect of the present invention, there is provided an automatic focus control device according to any one of the first to thirteenth aspects, wherein the blur filter as a basis for generating the restoration filter is provided. The image profile is similar to the shape of the stop.

According to a fifteenth aspect of the present invention, in the automatic focus control apparatus according to the fourteenth aspect, the range of the constant term determined by the ratio of the signal of the restoration filter to the noise is 0.0005. -0.05.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment in which an automatic focus control device according to the present invention is applied to a digital still camera will be described below in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention.
1 is a configuration diagram of a digital still camera according to the present invention. The digital still camera shown in FIG.
A lens system 1 for forming an image on a CD, a diaphragm 2, a front end unit 3 for outputting image data corresponding to a subject image, and an image preprocessor (Imag) for performing various data processing of image data
e Pre-Processor, hereinafter referred to as “IPP”) Part 4
A CPU I / F 5, a CPU 6 for controlling the operation of each part of the digital still camera, a focus lens controller 7 for controlling the drive of the lens system 1, and an aperture controller 8 for controlling the aperture value (f-number) of the aperture 2. And

The lens system 1 includes an imaging lens and a focus lens. The front end unit 3 converts a subject image formed by the lens system 1 into an electric signal (analog image data) and outputs the converted signal, and performs noise removal and gain adjustment of the electric signal input from the CCD 31. A signal processing unit 32 and a CCD 31 via the signal processing unit 32
A / D converter 33 that converts analog image data input from the digital camera into digital image data and outputs the digital image data to IPP unit 4
And.

The IPP unit 4 separates the digital image data input from the front end unit 3 into R, G, and B components (RGB digital signals).
And an RGB gain adjustment unit 42 that adjusts the gain of each color component of the separated RGB digital signal to output to a luminance value generation unit 43, and converts an input RGB digital signal into a luminance signal to perform FFT (IFFT). A luminance value generating unit 43 to be output to the calculating unit 44; a spatial component of the luminance signal input from the luminance value generating unit 43 is converted into a frequency component to be output to the filtering unit 45; (IFFT) operation unit 44 that performs IFFT conversion, inversely converts the space component into a spatial component, and outputs the result to the negative value integration unit 48.

Further, based on the restoration filter stored in the restoration filter data ROM 46, the IPP unit 4
A filtering unit 45 for performing a restoration process of the signal converted to the frequency component by the FFT (IFFT) operation unit 44, a restoration filter data ROM 46 storing data of a plurality of restoration filters respectively corresponding to a plurality of point image radii, After filtering the signal converted to frequency component,
A high-frequency component integrator 4 that outputs to the CPU 6 a high-frequency component integrated value obtained by extracting and accumulating the specific high-frequency component.
7 and a negative value integrated value obtained by integrating the negative values of the spatial frequency components input from the FFT (IFFT) calculation unit 44 are represented by C
And a negative value accumulator 48 for outputting to the PU 6. In addition,
Although each function of the IPP unit 4 can be realized by software, it is preferable to configure the function by hardware as shown in the figure because high-speed processing can be performed.

As described above, the CPU 6 controls the operation of each section of the digital still camera. Specifically, for example, the CPU 6 performs the following operations based on the input high-frequency component integrated value and negative value integrated value. One-shot AF control is performed by calculating an AF evaluation value.

Next, the outline of the AF operation of the digital still camera having the above configuration will be described.

First, coarse AF by one-shot AF
The operation is performed. CCD at initial focus lens position
RGB digital color signals obtained from the A / D converter 33 from the A / D converter 31 are input to an IPP unit 4 that performs image signal processing. In the IPP unit 4, first, the luminance value is converted into a luminance signal by the luminance value generation unit 43, and then the spatial component is converted into a frequency component by the FFT (IFFT) calculation unit 44. The filtering unit 45 performs a restoration process on the signal converted into the frequency component based on the data (1 restoration filter) read from the restoration filter data ROM 46. The signal subjected to the filtering process is output to the high-frequency component integrator 47 and F
The data is output to the FT (IFFT) calculation unit 44.

The high-frequency component integrator 47 extracts a specific high-frequency component of the input signal, and outputs a high-frequency component integrated value obtained by accumulating the specific high-frequency component to the CPU 6 via the CPU I / F 5.

On the other hand, the data subjected to the filtering process is again input to the FFT (IFFT) calculating unit 44, converted into a spatial component again, and output to the negative value integrating unit 48. Here, the re-converted data (image data) may include a negative value. In the negative value integrating unit 48, a negative value integrated value obtained by integrating the negative values of the reconverted data is output to the CPU 6 via the CPU I / F5. That is, the integrated value of the high-frequency component and the integrated value of the negative value corresponding to one restoration filter are input to the CPU 6.

The series of processing of filtering processing → high frequency component integration → IFFT → negative value integration is repeated by the number of restoration filters, and the high frequency component integration values and the negative value integration values by the number of restoration filters are output to the CPU 6. You.

The CPU 6 calculates an AF evaluation value based on the input integrated value of the high-frequency component and the integrated value of the negative value, and searches for a minimum value, for example. The AF evaluation value is calculated by, for example, the following equation (1). Specifically, the negative value integrated value of the AF area and the integrated value of the high frequency component in the specific area are calculated, respectively.
The ratio between the calculated negative value integrated value group and the calculated high frequency component integrated value is used as the AF evaluation value.

(Ratio between negative value integrated value and high frequency component integrated value) = | 1000− (negative value integrated value) | / (high frequency component integrated value) (1) where || is an absolute value

Then, the corresponding focus lens position (target position), that is, the approximate focus position (coarse focus detection position) is specified using the restoration filter number corresponding to the retrieved minimum value as the focus index. Then, the CPU 6 outputs control data for instructing the focus lens control unit 7 to move the focus lens to the approximate focus position.
The focus lens control unit 7 drives the focus lens to the approximate focus position.

Next, a fine AF operation is performed. First, imaging is performed again at the approximate focus position, and the captured image data is subjected to image restoration using a restoration filter corresponding to a point image radius of 1 to calculate an AF evaluation value. Next, the focus lens is further slightly moved, the image is captured, and the captured image data is restored with a restoration filter corresponding to a point image radius of 1 to calculate an AF evaluation value. Here, the restoration filter corresponding to the point image radius 1 is used, but any restoration filter corresponding to the point image radius 5 or less may be used. The imaging, the image restoration, and the calculation of the AF evaluation value are the same as those described above, and a description thereof will be omitted.

The CPU 6 compares the AF evaluation values of at least two points at the approximate in-focus position and specifies in which direction the final in-focus position is. Then, while gradually moving the focus lens in the specified direction, image capturing → image restoration processing using a restoration filter corresponding to a point image radius of 1 → AF
The calculation of the evaluation value → the determination of the AF evaluation value (whether or not it is the minimum value) is repeatedly performed to specify the final in-focus position.

A specific example of the AF operation will be described with reference to FIG. It is an explanatory view for explaining a specific example of the AF operation, and is a diagram (upper diagram) for explaining an operation of detecting a coarsely focused position and a diagram for explaining an operation of detecting a finely focused position (FIG. (Shown below) in association with each other.

The upper part of FIG. 2 shows the lens position, the object position,
The relationship between the restoration filter and the one-shot AF evaluation value is shown. The filtering unit 45 sets the focal position to ∞
(Recovery filter No. 7) corresponding to each distance between (infinity) and Near (closest). 1 to No. 7 (filter group). Each restoration filter No. 1
-No. 7, the image is restored, and the AF evaluation value is obtained.
Here, the focal point is a filter number indicating the minimum value of the one-shot AF evaluation value, and in FIG. At 6, the CPU 6 outputs a signal to the effect that the AF evaluation value is the approximate focus position to the focus lens controller 7. Based on this signal, the focus lens control unit 7 sets the focus lens to the filter No. Move to the position corresponding to 6.

The focus lens is set to the filter No. After being moved to the position corresponding to 6, the image is taken again, the image is restored by the restoration filter corresponding to the point image radius 1, and the AF evaluation value is calculated. Next, the focus lens is further slightly moved, the image is captured, and the captured image data is restored with a restoration filter corresponding to a point image radius of 1 to calculate an AF evaluation value. By comparing the AF evaluation values of at least two points at the approximate in-focus position, the direction (closest direction or infinity direction) of the final in-focus position is specified. In the example shown in the figure, since it is possible to specify that there is a final focus position in the infinity direction, as shown in the figure, while gradually moving the focusing lens in the infinity direction, imaging → point image radius 1 Is repeated by the restoration filter corresponding to (1) → the calculation of the AF evaluation value → the determination of the AF evaluation value (whether or not it is the minimum value) to reach the final in-focus position.

As described above, in the first embodiment, an image is taken at the initial focus lens position, and the obtained image is subjected to image restoration using a plurality of restoration filters corresponding to the point image radius. An AF evaluation value is calculated for the image group restored for each restoration filter, and a rough focus position is determined by collating the AF evaluation values. Subsequently, a point image is formed for the image captured at the rough focus position. Image restoration is performed using a restoration filter having a radius of 1, an AF evaluation value is calculated,
Since the final focus position is specified by referring to the AF evaluation value every time the focus lens is driven, the memory capacity for storing the restoration filter can be reduced, and the high-precision automatic focusing can be performed with an inexpensive configuration. The operation can be performed.

In the first embodiment, the AF evaluation value is A
Since the calculation is performed based on the ratio between the negative value integrated value and the high frequency component integrated value in the F area, it is possible to calculate the AF evaluation value with high accuracy.

Also, in the first embodiment, since the point image radius of the restoration filter used for fine adjustment is set to 5 or less, it is possible to perform image restoration with high accuracy while assuring more accurate focusing characteristics. I have.

In the first embodiment, an example is described in which seven restoration filters are provided for coarse AF adjustment, but the present invention is not limited to this. Further, the calculation formula for calculating the AF evaluation value is not limited to the above formula (1). Further, the point image radius of the restoration filter used in the fine adjustment is set to 1, but is not limited to this, and any point image radius of 5 or less may be used.

(Embodiment 2) Regarding Embodiment 2,
This will be described with reference to FIGS. In the second embodiment, an AF operation when a digital still camera having the configuration of the first embodiment is provided with a zoom lens will be described.

In the one-shot AF, as described above,
A for an image restored by multiple restoration filters
The focus position (point image radius index) is specified by calculating the F evaluation value and determining the calculated AF evaluation value.

FIG. 3 shows the relationship between the zoom lens position, the subject distance, and the point image radius index. As shown in the figure, since the point image radius index series differs depending on the focal length, if the zoom lens is used, if the focal length is changed and the correction is not performed, the focus lens is driven to an inappropriate position. Would be. That is, the conventional one-yacht AF mainly uses a single focus lens in which a series of point image radii is determined to be one, and a zoom lens has an infinite number of series of point image radii. Has been considered unsuitable.

Therefore, in the second embodiment, the zoom lens position is detected, and position information for driving the focus lens corresponding to the zoom lens position is determined based on the detected zoom lens position and the point image radius index. By driving the focus lens to the in-focus position with reference to the stored table, an adverse effect on focusing accuracy when using a zoom lens is eliminated.

FIG. 4 is a diagram showing a configuration of a zoom lens and a zoom lens position correction unit of a digital still camera according to the second embodiment. The digital still camera according to the second embodiment is obtained by adding the zoom lens 9 and the zoom lens position correction unit 10 shown in FIG. 4 to the digital still camera according to the first embodiment.

The zoom lens position corrector 10 shown in FIG.
Is a position information output unit (not shown) provided on the zoom lens 9 for outputting position information (focal length information) of the zoom lens 9, and a zoom lens 9 output from the position information output unit (not shown). A zoom lens position detection unit 101 that detects position information (focal distance information) of the zoom lens 9 based on the position information, and a focus based on the detected position information (focal distance information) of the zoom lens 9 and a point image radius index. A selector 102 for specifying position information of the focus lens in the lens position drive table 103 and a focus lens drive position table ROM 103 for storing the position information of the zoom lens 9 and the position information of the focus lens in association with each other. I have.

Focus lens drive position table ROM 103
Has a drive position setting area for the zoom lens positions 1 to 3, and stores the position information of the focus lens for each of the drive position setting areas for the zoom lens positions 1 to 3. That is, in the focus lens drive position table ROM 103, one of the head addresses of the drive position setting areas for the zoom lens positions 1 to 3 is designated based on the position information of the zoom lens 9, and the point image radius index is offset (pointer). Is designated as focus lens position information.

Next, the AF operation in the third embodiment will be described. First, in the zoom lens position correction unit 10, a position information output unit (not shown) outputs position information (focal length information) of the zoom lens 9 to the zoom lens position detection unit 101. The zoom lens position detection unit 101 detects position information (focal length information) of the zoom lens 9 based on the position information of the zoom lens 9 output from a position information output unit (not shown), and outputs the information to the selector 102. Selector 1
Reference numeral 02 designates any one of the drive position setting areas for the zoom lens positions 1 to 3 as an appropriate area of the focus lens drive position table ROM 13 based on the detected position information (focal distance information).

On the other hand, the image picked up at the initial focus lens position is restored at each point image radius, an AF evaluation value is calculated, and the focus position (point image radius index) is output to the selector 102 by the CPU 6. . The selector 102 designates the position information of the focus lens of the focus lens drive position table ROM 103 based on the focus position (point image radius index) in the designated area of the focus lens drive position table ROM 103. Then, the focus lens control unit 7 reads the position information of the designated focus lens from the focus lens drive position table ROM 103, and drives the focus lens based on the read position information.

More specifically, for example, when the photograph is taken at the zoom lens position 3, the zoom lens position detecting unit 101
Detects the position 3 (focal length) of the zoom lens 9, and selects the focus lens driving position table ROM1
The head address of the drive position setting area for zoom lens position 3 of 03 is designated. On the other hand, the selector 102
When the CPU 6 outputs “2” as the focus position (point image radius index), the index value “2” is specified as an offset to the specified head address. As a result, in the figure, "0A" is designated as the position information of the focus lens. The focus lens control unit 7 determines the designated position information “0”.
A "is read out, and the focus lens is driven based on the position information.

As described above, according to the second embodiment, in the one-shot AF using the zoom lens, the zoom lens position is detected, and the zoom is determined based on the detected zoom lens position and the point image radius index. Since the focus lens is driven to the in-focus position with reference to the table storing the position information for driving the focus lens corresponding to the lens position, it is possible to suppress the variation at the time of focusing by the zoom lens, A highly accurate focusing operation can be performed.

In the second embodiment, the read area of the focus lens position table ROM 103 is switched. However, a configuration may be used in which a RAM is used as a table to arithmetically generate and rewrite position data.

The AF operation using the zoom lens as in the second embodiment may be combined with the AF operation according to the first embodiment. This makes it possible to perform a more accurate AF operation.

(Embodiment 3) Regarding Embodiment 3,
This will be described with reference to FIGS. In the third embodiment, an AF operation when a digital still camera having the configuration of the first embodiment is provided with a zoom lens will be described.

In the third embodiment, the position of the zoom lens is detected, and one-shot AF is performed based on the detected position information.
It controls shooting conditions during operation, and particularly controls the aperture value of the aperture as shooting conditions. FIG. 5 is an explanatory diagram showing the correspondence between the zoom lens position and the aperture value.

The aperture control unit 8 changes the aperture value of the aperture 2 according to the detected zoom lens position. In particular,
For example, as shown in FIG. 5, the aperture control unit 8 sets the aperture value to “11” when the zoom lens 9 is at the zoom lens position 1, and sets the aperture value to “8” when the zoom lens 9 is at the zoom lens position 2. In the case of the zoom lens position 3, "6.7" is set as the aperture value.

As a result, a point image radius index having characteristics as shown in FIG. 6 can be obtained. The characteristics shown in FIG.
As compared with the characteristics shown in (1), the point image radius index series at the zoom lens position 1 has a characteristic that is more depressed, and the point image radius index series at the zoom lens position 3 has a characteristic that can be further raised. As a result, a variation in the point image radius index series due to the zoom lens position is suppressed, and an accurate focusing operation is realized. Other AF operations are the same as those in the first or second embodiment, and a description thereof will be omitted.

As described above, in the third embodiment, the zoom lens position is detected, and the photographing conditions during the one-shot AF operation are controlled based on the detected position information. Variations in the point image radius index sequence due to the position can be suppressed, and a highly accurate focusing operation can be performed.

The AF operation using the zoom lens as in the third embodiment may be combined with the AF operation in the first embodiment. This makes it possible to perform a more accurate AF operation.

(Embodiment 4) Regarding Embodiment 4,
This will be described with reference to FIGS. In the fourth embodiment, a case will be described in which two initial focus lens positions are set during the AF operation in the digital still camera having the configuration of the first embodiment.

In the fourth embodiment, as shown in FIG. 7, filter Nos.
Tables 1 and 2 are provided to store lens position data of the focus lens corresponding to 8). Table 1 corresponds to a first initial focus lens position (∞), and table 2 corresponds to a second initial focus lens position (Near).

FIG. 8 is an explanatory diagram for explaining the AF operation in the fourth embodiment. In particular, the upper diagram shows each restoration filter (No.) when an image is taken at the first initial focus lens position (∞). .1 to No. 8) show an example of the AF evaluation value, and the lower figure shows the second initial focus lens position (Near).
, Each restoration filter (No. 1 to No. 1) when the image is picked up.
An example of the AF evaluation value in 8) is shown. In the fourth embodiment, the first initial focus lens position is set to the infinity position (∞), and the second initial focus lens position is set to the closest position (6).
0 cm).

First, at the first initial focus lens position (infinity position), an image is captured, and image restoration is performed for each restoration filter corresponding to the point image radius to obtain an AF evaluation value. FIG.
In the example shown in FIG. 6 is selected as the focusing index.

Next, the focus lens is driven to the second initial focus lens position (closest position: 60 cm). here,
An image is fetched again, and image restoration is performed for each restoration filter to obtain an AF evaluation value. In the example shown in FIG.
2 is selected as the focus index.

The table 1 storing the focus lens position based on the focus index selected from the first initial focus lens position and the focus index selected from the second initial focus lens position. , 2 are read out of the position data of the focus lens. In this embodiment, the filter No. selected from the table 1 at the first initial focus lens position. The lens position data “40h (hexadecimal display: 8 bits)” corresponding to No. 6 is read. The filter No. selected from the table 2 at the first initial focus lens position. The lens position data “80h” corresponding to No. 2 is read. Then, a weighted average of the read lens position data “40h” and “80h” is calculated. The specific calculation result is (40h + 80h) /
2 = 60h (the weight coefficients are each set to 1).

Then, using the calculated weighted average value “60h” as the final focus position, the focus lens control section 7 moves the focus lens to the final focus position.

As described above, according to the fourth embodiment, since the initial focus lens position is set at two points, it is possible to improve the specific accuracy of the focal point.

In the fourth embodiment, at least one of the two points of the initial focus lens position is set to the infinity position or the closest position. It is possible to do.

In the fourth embodiment, the final focus position is calculated by performing a weighted average of the lens position data at the first initial focus lens position and the lens position data at the second initial focus lens position. As a result, it is possible to improve the accuracy of specifying the focal point.

In the fourth embodiment, the closest position is set to 60 [cm], but the present invention is not limited to this. Also, the number of restoration filters is not limited to those listed here. Further, the weighting coefficients are all set to 1, but are not limited to this.

(Embodiment 5) Regarding Embodiment 5,
This will be described with reference to FIGS. In the fifth embodiment, in the fourth embodiment, the focus lens position is set to the second position only when it is determined that the subject is at a short distance by estimating the focus position based on the first initial focus lens position (infinity position). Is moved to the closest position, which is the initial focus lens position, and further imaging is performed there, and image restoration is performed to specify the focus position.

FIG. 9 is an explanatory diagram for explaining the AF operation according to the fifth embodiment (when imaging at the second initial focus lens position is necessary), and FIG. 10 is a diagram for explaining the AF operation according to the fifth embodiment. FIG. 7 is a diagram for explaining the operation (when imaging at the second initial focus lens position is unnecessary). In the fifth embodiment, the first initial focus lens position is set at the infinity position (∞), and the second initial focus lens position is set at the closest position (60 cm).
The reason for setting the initial focus lens position in this way is to make the focusing applicable range as wide as possible.
For example, the first initial focus lens position is set to 300 [cm].
Alternatively, the second initial focus lens position may be set to 100 [cm] or the like.

In FIG. 9, the upper figure shows each restoration filter (No. 1) when an image is taken at the first initial focus lens position (∞).
1 to No. 8) shows an example of the AF evaluation value in 8). The lower figure shows A in each restoration filter (No. 1 to No. 8) when the image is captured at the second initial focus lens position (Near).
An example of the F evaluation value is shown.

In FIG. 9, first, at the first initial focus lens position (infinity position), an image is taken, and image restoration is performed for each restoration filter corresponding to the point image radius to obtain an AF evaluation value. In FIG. 6 is selected as the focusing index. This indicates that the subject is at a short distance. Therefore, the focus lens is driven to the second initial focus lens position (closest position: 60 cm). Here, an image is fetched again, and image restoration is performed for each restoration filter to obtain an AF evaluation value. In the figure (lower figure), the filter N
o. 2 is selected as the focus index.

Here, in the same manner as in the fourth embodiment,
Based on the focus index selected from the first initial focus lens position and the focus index selected from the second initial focus lens position, the lens of the focus lens is obtained from the tables 1 and 2 shown in FIG. Each position data is read out, a weighted average is taken of the read out lens position data to determine a final focus position, and the focus lens control unit 7 moves the focus lens to the final focus position.

FIG. 10 shows each restoration filter (No. 1 to N) when an image is taken at the first initial focus lens position (位置).
o. An example of the AF evaluation value in 8) is shown.

As shown in FIG. 10, first, an image is captured at a first initial focus lens position (infinity position).
Image restoration is performed for each restoration filter corresponding to the point image radius,
An AF evaluation value is obtained. In FIG. 2 is selected as the focus index. Thus, the filter No. When 2 is the focusing index, it is understood that the subject is at a long distance. In this case, since the focusing accuracy is sufficient even from the focusing index value from the first initial focus lens position (the position at infinity), the focusing lens control unit 7 directly moves the focus index value to the position indicated by the focusing index value. Drive the focusing lens. That is, the AF operation is performed only with one shot when the initial focus lens position is set at the infinity position. As a result, it is possible to omit the restoration scanning that has been performed uniformly regardless of the subject distance,
High-speed automatic focus control with necessary and sufficient focusing accuracy is possible.

As described above, according to the fifth embodiment, when the in-focus position is estimated based on the first initial focus lens position (infinity position), when the subject is at a long distance, the first Is determined as the final in-focus position, while the in-focus position based on the first in-focus lens position (infinity position) is determined to be at a short distance. In this case, the focus lens position is moved to the nearest position, which is the second initial focus lens position, and further imaging is performed there, and image restoration is performed to specify the in-focus position. The operation can be omitted, and high-speed automatic focus control can be performed.

(Embodiment 6) Embodiment 6
This will be described with reference to FIGS. Embodiment 6
In the fourth embodiment, the focus lens position is changed to the second initial focus lens only when it is determined that the subject is at a long distance by estimating the focus position based on the first initial focus lens position (closest position). Move to the infinity position which is the position,
Therefore, further imaging is performed, and the image is restored to specify the focus position.

FIG. 11 is an explanatory diagram for explaining the AF operation according to the sixth embodiment (when imaging at the second initial focus lens position is necessary), and FIG. 10 describes the AF operation according to the sixth embodiment. (In the case where imaging at the second initial focus lens position is unnecessary) is shown. In the sixth embodiment, the first initial focus lens position is set at the closest position (60 cm), and the second initial focus lens position is set at the infinity position (∞).

In FIG. 11, the upper figure shows an example of the AF evaluation value in each restoration filter (No. 1 to No. 8) when the image is taken at the first initial focus lens position (60 cm), and the lower figure shows the second example. An example of an AF evaluation value in each restoration filter (No. 1 to No. 8) when an image is captured at the initial focus lens position (位置) of FIG.

In FIG. 11, first, at the first initial focus lens position (60 cm), an image is captured, and image restoration is performed for each restoration filter corresponding to the point image radius to obtain an AF evaluation value. In FIG. 6 is selected as the focusing index. This indicates that the subject is at a long distance. Therefore, the focus lens is driven to the second initial focus lens position (infinity position). Here, an image is fetched again, and image restoration is performed for each restoration filter to obtain an AF evaluation value. In FIG. 2 is selected as the focus index.

Here, in the same manner as in the fourth embodiment,
Based on the focus index selected from the first initial focus lens position and the focus index selected from the second initial focus lens position, the lens of the focus lens is obtained from the tables 1 and 2 shown in FIG. Each position data is read out, a weighted average is taken of the read out lens position data to determine a final focus position, and the focus lens control unit 7 moves the focus lens to the final focus position.

FIG. 12 shows the first initial focus lens position (6
0 cm), each restoration filter (No. 1 to No. 1).
No. An example of the AF evaluation value in 8) is shown.

As shown in FIG. 12, first, at the first initial focus lens position (60 cm), an image is captured, and image restoration is performed for each restoration filter corresponding to the point image radius.
Obtain the F evaluation value. In FIG. 3 is selected as the focusing index. Thus, the filter No. When 3 is the focusing index, it is understood that the subject is at a short distance. In this case, the first initial focus lens position (60c
Since the focusing accuracy is sufficient even from the focusing index value from m), the focus lens control unit 7 drives the focusing lens to the position indicated by the focusing index value as it is. That is, the AF operation is performed only with one shot at the initial focus lens position (60 cm). This makes it possible to omit the restoration scan that has been performed uniformly regardless of the subject distance, and to perform high-speed automatic focus control with necessary and sufficient focusing accuracy.

As described above, according to the sixth embodiment, when the in-focus position is estimated based on the first initial focus lens position (closest position), when the subject is at a short distance, the first The in-focus position calculated at the initial focus lens position is determined as the final in-focus position, while the in-focus position is estimated based on the first initial focus lens position (closest position), and the subject is determined to be at a long distance. In this case, the focus lens position is moved to the infinity position, which is the second initial focus lens position, the image is captured, the image is restored, and the in-focus position is specified. And high-speed automatic focus control becomes possible.

(Embodiment 7) Embodiment 7
This will be described with reference to FIG. In the seventh embodiment, the range step of the point image radius of the restoration filter used for the image restoration at the second initial focus lens position in the fourth embodiment is performed for the image restoration at the first initial focus lens position. This is smaller than the range step of the point image radius of the restoration filter.

FIG. 13 is an explanatory diagram for explaining the AF operation in the seventh embodiment. In particular, the upper diagram shows each restoration filter (No.) when an image is taken at the first initial focus lens position (∞). .1 to No. 8), the lower figure shows the second initial focus lens position (Nea).
r) and the restoration filters (No. 1 ′ to N)
o. 7 shows an example of the AF evaluation value in 7 ′). As shown in the figure, the range step of the point image radius of the restoration filter used for image restoration at the second initial focus lens position (closest position) is performed by changing the image restoration at the first initial focus lens position (∞). Is set to be smaller than the range step of the radius of the point image of the restoration filter provided for the above.

In the figure, first, an image is taken in at a first initial focus lens position (infinity position), and image restoration is performed for each restoration filter corresponding to the point image radius to obtain an AF evaluation value. In FIG. 6 is selected as the focusing index. At this time, the step of the corresponding point image radius of the restoration filter is 8.

Next, the focus lens is driven to the second initial focus lens position (closest position: 60 cm). here,
The image is fetched again, the image is restored for each restoration filter, and an AF evaluation value is obtained. Here, at the first initial focus lens position, a rough focus range is specified, and the restoring scan of the entire range has many wasteful parts. The radius of the corresponding point image is four steps, and the restoration scanning range covers only three steps of the restoration range at the first initial focus lens position. This realizes high-speed automatic focus control with necessary and sufficient focusing accuracy. In FIG. 4 'is selected as the focusing index.

As described above, in the seventh embodiment, the range step of the point image radius of the restoration filter used for image restoration at the second initial focus lens position is as follows.
Since the range step of the point image radius of the restoration filter used for image restoration at the first initial focus lens position is smaller and the range to which the restoration filter group is applied is narrowed, high-speed and high-precision Focusing can be specified.

In the seventh embodiment, 60 cm is set as the closest position, but the present invention is not limited to this. Also, the number of restoration filters is not limited to those listed here. Further, the step of engraving the point image radius of the restoration filter in the first initial focus lens is 8,
Although the step of enlarging the point image radius of the restoration filter in the second initial focus lens is set to 4, it is not limited to this.

(Eighth Embodiment) Regarding the eighth embodiment,
This will be described with reference to FIGS. In the eighth embodiment, the point image profile of the blur filter, which is a basis for generating a restoration filter (Wiener filter) used for image restoration, is made similar to the shape of the stop. FIG. 14 to FIG.
FIG. 21 is a diagram illustrating an example of a point image profile of a blur filter that is a basis of a restoration filter according to the eighth embodiment.

In the eighth embodiment, a Wiener filter is used as a restoration filter for automatic focus control using the image restoration filter. Although a blur filter is assumed as a basis for generating the restoration filter, the cross-sectional shape of the point image distribution profile representing the blur is set to be similar to the aperture as shown in FIGS.

Here, a circular shape as shown in FIGS. 14 and 15 is often used because of easy generation of a filter. Some lenses are limited in their heavy fractions and have a hexagonal aperture shape due to the drive load of the aperture blades. In the case of a digital video camera provided with such an aperture, a point image distribution profile having a shape as shown in FIG. 16 further improves the restoration accuracy and also improves the focusing accuracy.

The point image distribution profiles are shown in FIGS.
The shape is not limited to a columnar shape or a Gaussian shape as shown in FIG. 16, but may be a complex shape of the two or a polygonal shape such as an octagon.

The filter frequency characteristic of the restoration filter is calculated by the following equation (2) from the frequency characteristic of the blur filter. Here, the frequency characteristic of the blur filter is H
(U, V), the frequency characteristic of the restoration filter is K (U, V)
Then, the frequency characteristic K (U, V) of the restoration filter can be calculated as in the following equation (2).

K (U, V) = H (U, V) * / {H (U, V) * · H (U, V) + W} (2) where H (U, V) * : Conjugate complex number of H (U, V) W: constant (determined by the ratio of signal and noise of the restoration filter)

Here, a signal of a restoration filter (Wiener filter) used for image restoration and a frequency characteristic K (U,
V) and the range of the constant term W determined by the ratio of noise to the range of 0.0005 to 0.05,
By appropriately changing and adapting to a change in noise level such as a change in zoom or a change in focal length due to zoom, the accuracy of restoration is improved, which in turn leads to an improvement in focusing accuracy. In addition, in the manufacturing stage, by incorporating a restoration filter appropriately adapted to the characteristics of the CCD to be used, the focusing accuracy can be improved.

The restoration filter according to the eighth embodiment can be applied to the restoration filters according to the first to seventh embodiments.

As described above, in the eighth embodiment, the point image profile of the blur filter which is the basis for generating the restoration filter (Wiener filter) used for image restoration is made similar to the shape of the stop. Because
It is possible to improve the accuracy of image restoration and, consequently, the accuracy of specifying the focal point.

In the eighth embodiment, the range of the constant term W determined by the ratio between the signal of the restoration filter (Wiener filter) used for image restoration and the noise is set to 0.0.
Since it is set in the range of 005 to 0.05, it is possible to improve the accuracy of image restoration and, consequently, to improve the accuracy of specifying the focal point.

The present invention relates to the above-described first to eighth embodiments.
The present invention is not limited to this, and can be appropriately changed without changing the gist of the invention.

The automatic focus control device of the present invention can be widely applied to image input devices using an image pickup device such as a video camera and a still video camera.

[0108]

According to the first aspect of the present invention, the image data obtained by imaging at the initial focus lens position is restored using a plurality of restoration filters corresponding to the point image radius. Is performed, an AF evaluation value is calculated for the image data group restored for each restoration filter, and the calculated AF evaluation value is compared to determine an approximate focus position.
Next, image restoration is performed on the image data obtained by moving the focal lens from the approximate focus position using a restoration filter corresponding to an arbitrary point image radius, and A
Since the F evaluation value is calculated and the calculated AF evaluation value is referred to each time the focus lens is driven to determine the final focus position, a high-speed and high-precision focus operation can be performed.

According to the automatic focus control device of the second aspect, in the automatic focus control device of the first aspect,
Since the AF evaluation value is calculated based on the ratio between the negative value integrated value and the high frequency component integrated value in the AF area, it is possible to calculate the AF evaluation value with high accuracy.

According to the automatic focus control device according to the third aspect, in the automatic focus control device according to the first or second aspect, since an arbitrary point image radius is set to 5 or less, more accurate focusing is achieved. Operation becomes possible.

According to the automatic focus control device of the fourth aspect, in a one-shot AF having a zoom lens, the position of the zoom lens is detected, and based on the detected position of the zoom lens, the position of the zoom lens is made to correspond to the position of the zoom lens. Since the focus lens is driven to the in-focus position with reference to the table storing the position information for driving the focus lens, a high-precision focusing operation can be performed even when a zoom lens is used. .

According to the fifth aspect of the present invention, in a one-shot AF having a zoom lens, the position of the zoom lens is detected, and the image pickup during the focusing operation is performed based on the detected position of the zoom lens. Since the conditions are controlled, a highly accurate focusing operation can be performed even when a zoom lens is used.

According to the automatic focus control device of the sixth aspect, in the automatic focus control device of any one of the first to third aspects, the zoom lens position is determined based on the detected zoom lens position. Refer to the table that stores the position information for driving the focus lens in correspondence with
Since the focus lens is driven to the in-focus position, a highly accurate focusing operation can be performed even when a zoom lens is used.

Further, according to the automatic focus control device according to the seventh aspect, in the automatic focus control device according to any one of the first to third aspects, the position of the zoom lens is detected,
Since the imaging conditions at the time of the focusing operation are controlled based on the detected position of the zoom lens, a highly accurate focusing operation can be performed even when the zoom lens is used.

According to the automatic focus control device of the present invention, at least two initial focus lens positions are provided, and image data is output at each initial focus lens position.
The image data is subjected to image data restoration using a plurality of restoration filters corresponding to the point image radius, and an AF evaluation value is calculated for each image data group restored for each restoration filter. Check each AF evaluation value,
The focus position is calculated for each initial focus lens position, and the final focus position is determined based on the focus position calculated for each initial focus lens position. Focusing operation becomes possible.

According to the automatic focus control device of the ninth aspect, in the automatic focus control device of the eighth aspect,
Since at least one of the initial focus lens positions is set at the infinity position or the closest position, it is possible to reduce the limitation on the range for specifying the focus position.

According to the automatic focus control device of the tenth aspect, in the automatic focus control device of the eighth aspect, the focus positions calculated for each of the initial focus lens positions are weighted and averaged. Since the in-focus position is determined, the final in-focus position can be easily specified.

Further, according to the automatic focus control device according to the eleventh aspect, in the automatic focus control device according to the ninth aspect, the first initial focus lens position is set at infinity, and the second initial focus lens position is set. Is set to the closest position, image is taken at the first initial focus lens position and image data is output,
The image data is subjected to image data restoration using a plurality of restoration filters corresponding to the point image radius, and an AF evaluation value is calculated for each image data group restored for each restoration filter. The first focus position is calculated by comparing the AF evaluation values, and when the calculated first focus position is a long distance, the first focus position is set to the final focus position. If the first focus position is a short distance, the image is taken at the second initial focus lens position and image data is output, and the image data corresponds to the point image radius. The image data is restored using the plurality of restored filters thus calculated, the AF evaluation value is calculated for each of the image data groups restored for each of the restored filters, and the calculated AF evaluation values are collated to obtain a second combination. Calculating the focal position, Based of the in-focus position, so it was decided to determine the final focus position, it is possible to omit the imaging and restore operations of unwanted images, thereby enabling more rapid focusing operation.

According to the automatic focus control device of the twelfth aspect, in the automatic focus control device of the ninth aspect, the first initial focus lens position is set to the closest position, and the second initial focus lens position is set. Is set to an infinity position, an image is taken at a first initial focus lens position and image data is output,
The image data is subjected to image data restoration using a plurality of restoration filters corresponding to the point image radius, and an AF evaluation value is calculated for each image data group restored for each restoration filter. The first in-focus position is calculated by comparing the AF evaluation values, and when the calculated first in-focus position is a short distance, the first in-focus position is set as the final in-focus position. When it is determined that the first in-focus position is at a long distance, an image is taken at the second initial focus lens position and image data is output, and a plurality of image data corresponding to the point image radius The image data is restored using the restoration filter, the AF evaluation value is calculated for each of the image data groups restored for each restoration filter, and the calculated AF evaluation values are collated to determine the second focus position. Calculated based on the first and second focus positions. There, since it was decided to determine the final focus position, it is possible to omit the imaging and restore operations of unwanted images, thereby enabling more rapid focusing operation.

Further, according to the automatic focus control device according to the thirteenth aspect, in the automatic focus control device according to the eleventh or twelfth aspect, the restoration filter group used for image restoration at the second initial focus lens position. Since the range step and the applicable range of the point image radius are smaller than the range step and the applicable range of the point image radius of the restoration filter group used for image restoration in the first initial focus lens, a higher-speed and higher-accuracy matching is achieved. The focus operation becomes possible.

Further, according to the automatic focus control device according to the fourteenth aspect, in the automatic focus control device according to any one of the first to thirteenth aspects, a blur filter as a basis for generating the restoration filter is provided. Since the point image profile of was made similar to the shape of the aperture, the accuracy of image restoration can be improved,
Thereby, it is possible to specify the focus position with high accuracy.

According to the automatic focus control device of the fifteenth aspect, in the automatic focus control device of the fourteenth aspect, the range of the constant term determined by the ratio of the signal of the restoration filter to the noise is set to 0.1. Since the value is set to 0005 to 0.05, the accuracy of image restoration can be improved, and thereby, the focus position can be specified with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital still camera to which an automatic focus control device according to a first embodiment is applied.

FIG. 2 is an explanatory diagram for explaining a specific example of an AF operation according to the first embodiment;

FIG. 3 is a diagram illustrating a relationship between a zoom lens position, a subject distance, and a point image radius index.

FIG. 4 is a diagram illustrating a zoom lens and a zoom lens position correction unit of a digital still camera according to a second embodiment.

FIG. 5 is an explanatory diagram showing a correspondence between a zoom lens position and an aperture value in a third embodiment.

FIG. 6 is a diagram illustrating a relationship among a zoom lens position, a subject distance, and a point image radius index.

FIG. 7 is a diagram showing a table according to the fourth embodiment.

FIG. 8 is an explanatory diagram for explaining an AF operation according to a fourth embodiment.

FIG. 9 is an explanatory diagram for explaining an AF operation according to the fifth embodiment (when imaging at a second initial focus lens position is required)
It is.

FIG. 10 is an explanatory diagram for explaining an AF operation according to the fifth embodiment (in a case where imaging at a second initial focus lens position is unnecessary).

FIG. 11 is an explanatory diagram for explaining an AF operation according to a sixth embodiment (when imaging at a second initial focus lens position is required).

FIG. 12 is an explanatory diagram for explaining an AF operation according to the sixth embodiment (in a case where imaging at a second initial focus lens position is unnecessary).

FIG. 13 is an explanatory diagram for explaining an AF operation in the seventh embodiment.

FIG. 14 is a diagram illustrating an example of a point image profile of a blur filter serving as a basis of a restoration filter according to the eighth embodiment.

FIG. 15 is a diagram illustrating an example of a point image profile of a blur filter serving as a basis of a restoration filter according to the eighth embodiment.

FIG. 16 is a diagram illustrating an example of a point image profile of a blur filter serving as a basis of a restoration filter according to the eighth embodiment.

[Explanation of symbols]

 Reference Signs List 1 lens system 2 aperture 3 front end section 4 image preprocessor (IPP) section 5 CPU I / F 6 CPU 7 focus lens control section 8 aperture control section 9 zoom lens 10 zoom lens position correction section 31 CCD 32 signal processing section 33 A / D Converter 41 RGB separation unit 42 RGB gain adjustment unit 43 Luminance value generation unit 44 FFT (IFFT) calculation unit 45 Filtering unit 46 Restoration filter ROM 47 High frequency component integrator 48 Negative value integration unit 101 Zoom lens position detection unit 102 Selector 103 Focus Lens drive position table ROM

Claims (15)

    [Claims]
  1. An image data obtained by imaging at an initial focus lens position is subjected to image restoration using a plurality of restoration filters corresponding to a point image radius, and image data restored for each restoration filter. An AF evaluation value is calculated for the group, an approximate in-focus position is determined by comparing the calculated AF evaluation value, and an image obtained by imaging while moving the focusing lens from the approximate in-focus position is obtained. The data is subjected to image restoration using a restoration filter corresponding to an arbitrary point image radius to calculate an AF evaluation value, and the calculated AF evaluation value is referred to each time the focus lens is driven to obtain a final result. An automatic focus control device for determining a focus position.
  2. 2. The automatic focus control device according to claim 1, wherein the AF evaluation value is calculated by a ratio of a negative value integrated value and a high frequency component integrated value in an AF area. .
  3. 3. The automatic focus control device according to claim 1, wherein the arbitrary point image radius is set to 5 or less.
  4. 4. An image is captured at an initial focus lens position, image data is output, and the image data is restored using a plurality of restoration filters corresponding to a point image radius. An auto focus control device that calculates an AF evaluation value for each of the image data groups that have been restored to a predetermined position, determines the in-focus position by comparing the calculated AF evaluation values, includes a zoom lens and a focus corresponding to the zoom lens position. A table storing position information for driving the lens, a zoom lens position detecting unit for detecting the zoom lens position, and a zoom lens position detected by the zoom lens position detecting unit. A focus lens driving unit for driving the focus lens to a focus position.
  5. 5. An image is captured at an initial focus lens position, image data is output, and the image data is restored using a plurality of restoration filters corresponding to a point image radius. An auto focus control device that calculates an AF evaluation value for each of the image data groups restored in step (a) and determines the in-focus position by comparing the calculated AF evaluation value; and a zoom lens that detects the zoom lens position. An automatic focus control device comprising: a lens position detection unit; and an imaging condition control unit that controls imaging conditions during a focusing operation based on the zoom lens position detected by the zoom lens position detection unit. .
  6. 6. The automatic focus control device according to claim 1, wherein a table storing a zoom lens and position information for driving the focus lens in correspondence with the zoom lens position. A zoom lens position detecting means for detecting the zoom lens position; and a focus for driving the focus lens to a focus position with reference to the table based on the zoom lens position detected by the zoom lens position detecting means. An automatic focus control device comprising: lens driving means.
  7. 7. The automatic focus control device according to claim 1, wherein: the zoom lens; a zoom lens position detecting unit that detects a zoom lens position; and the zoom lens position detecting unit. And an imaging condition control means for controlling imaging conditions at the time of focusing operation based on the detected zoom lens position.
  8. 8. At least two initial focus lens positions are provided, an image is taken at each initial focus lens position, image data is output, and a plurality of restoration filters corresponding to a point image radius are used for the image data. The image data is restored to calculate an AF evaluation value for each of the image data groups restored for each restoration filter, and the calculated AF evaluation values are collated to focus on each of the initial focus lens positions. An automatic focus control device that calculates a position and determines a final focus position based on the focus position calculated for each of the initial focus lens positions.
  9. 9. The automatic focus control device according to claim 8, wherein at least one of the initial focus lens positions is set to an infinity position or a closest position.
  10. 10. The automatic focus control device according to claim 8, wherein the final focus position is determined by averaging the focus positions calculated for each of the initial focus lens positions. Automatic focus control device.
  11. 11. The automatic focus control device according to claim 9, wherein the first initial focus lens position is set at an infinity position and the second initial focus lens position is set at a closest position. Image data is captured at the focal lens position, image data is output, and the image data is restored using a plurality of restoration filters corresponding to the point image radius, and the image data is restored for each restoration filter. An AF evaluation value is calculated for each group, a first focus position is calculated by comparing the calculated AF evaluation values, and when the calculated first focus position is a long distance,
    The first focus position is determined as a final focus position, and when the first focus position is a short distance, the second focus position is determined.
    At the initial focus lens position, image data is output, and the image data is restored for each image by using a plurality of restoration filters corresponding to the point image radius. An AF evaluation value is calculated for each of the image data groups, a second focus position is calculated by comparing the calculated AF evaluation values, and a final focus position is calculated based on the first and second focus positions. An automatic focus control device for determining an in-focus position.
  12. 12. The automatic focus control device according to claim 9, wherein the first initial focus lens position is set at a closest position, the second initial focus lens position is set at an infinity position, and the first initial focus lens position is set at an infinity position. Image data is captured at the focal lens position, image data is output, and the image data is restored using a plurality of restoration filters corresponding to the point image radius, and the image data is restored for each restoration filter. An AF evaluation value is calculated for each group, and the calculated AF evaluation values are collated to calculate a first focus position. When the calculated first focus position is a short distance,
    The first focus position is determined as a final focus position, and when the first focus position is a long distance, the second focus position is determined.
    The image data was output at the initial focus lens position of, and the image data was restored using a plurality of restoration filters corresponding to the point image radius, and the image data was restored for each restoration filter. An AF evaluation value is calculated for each of the image data groups, a second focus position is calculated by comparing the calculated AF evaluation values, and a final focus position is calculated based on the first and second focus positions. An automatic focus control device for determining an in-focus position.
  13. 13. The automatic focus control device according to claim 11, wherein a range step and an applicable range of a point image radius of a restoration filter group used for image restoration at the second initial focus lens position are set to be: An automatic focus control device, characterized in that a point image radius of a restoration filter group used for image restoration in a first initial focus lens is smaller than a range step and an applicable range.
  14. 14. The automatic focus control device according to claim 1, wherein a point image profile of a blur filter as a basis for generating the restoration filter is made similar to a shape of an aperture. An automatic focus control device, characterized in that:
  15. 15. The automatic focus control device according to claim 14, wherein a range of a constant term determined by a ratio between a signal of the restoration filter and a noise is 0.0005 to 0.05. Automatic focus control.
JP10325345A 1998-11-16 1998-11-16 Automatic focus controller Pending JP2000152064A (en)

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JP2003075717A (en) * 2001-09-06 2003-03-12 Nikon Corp Distance detecting device
US6928241B2 (en) 2002-09-12 2005-08-09 Canon Kabushiki Kaisha Autofocus apparatus and method and image sensing apparatus
US8570432B2 (en) 2010-09-06 2013-10-29 Canon Kabushiki Kaisha Focus adjustment apparatus and image capturing apparatus
JP2015521394A (en) * 2012-03-28 2015-07-27 ソニー株式会社 System and method for performing depth estimation by utilizing an adaptive kernel
JP2015207019A (en) * 2013-11-19 2015-11-19 パナソニックIpマネジメント株式会社 Imaging apparatus
US9571719B2 (en) 2013-11-19 2017-02-14 Panasonic Intellectual Property Management Co., Ltd. Image-capturing apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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