JPH11295588A - Automatic focus controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To substantially reduce product-sum operations and to provide a high-speed automatic focus controller by detecting the color information of the image data of an AF area for respective color components, deciding a specified color component in charge of the calculation of an AF evaluation value based on the detected result and calculating the AF evaluation value by the specified color component. SOLUTION: Signals for which filtering is executed are outputted to a high frequency component integrator 46 and also outputted to an error component integrator 47. In a CPU 7, the AF evaluation value is calculated based on a high frequency component integrated value inputted from the high frequency component integrator 46 and a negative value integrated value inputted from the error component integrator 47 and the minimum value is retrieved. Then, a corresponding focus lens position is specified with a restoration filter number corresponding to the retrieved minimum value as a focusing point index. In such a manner, the color information of the image data of the AF area is detected for the respective color components, the specified color component in charge of the calculation of the AF evaluation value is decided based on the detected result, the AF evaluation value is calculated by the specified color component and a focusing position is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] 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, as an in-focus position determining method in an automatic focus control device, there are an AF method using infrared rays or ultrasonic waves, and a passive AF method such as external light passive or hill-climbing servo. In particular, digital still video cameras (hereinafter "DS
VC), a passive AF method that does not require a special distance measuring component is often used. In such a passive AF method, a method of detecting a focus position in one shot in recent years is disclosed in, for example, Japanese Patent Laid-Open No. 6-181.
No. 532, there is an "in-focus position detecting device for an electronic camera". Such a focus position detecting device detects a focus position in one shot by using a restoration filter.

More specifically, such an in-focus position detecting device obtains and stores a plurality of point spread functions of an optical imaging system or functions obtained by converting the point spread functions of an optical imaging system at a focal position and lens positions before and after the focal position. Characteristic value storage means, image restoration means for restoring image data for one screen or a part thereof for each of the plurality of lens positions by the characteristic values stored in the characteristic value storage 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. In addition, it is possible to perform more accurately.

[0004]

However, in the prior art, a one-shot AF is performed using a restoration filter.
Is performed, the amount of calculation for restoring the image data becomes large, and the application range of the point spread function is limited.

In the conventional AF, a luminance signal Y component is generated from a color signal from a CCD, for example, an RGB signal and used. However, in order to convert from the RGB component to the Y component, three multiplications and two additions per pixel are performed.
It requires a so-called multiply-accumulate operation. VGA (640 × 48
In the case of DSVC having a relatively small number of pixels (eg, 0 pixels), not so high-speed processing is required.
Since the response time expected to have the number of pixels such as (1280 × 1024 pixels) does not change so much, higher-speed processing is required.

[0006] In one-shot AF using a restoration filter, the characteristics of the restoration filter used for image restoration and the high-frequency setting range in calculating the AF evaluation value greatly influence the focus determination. In particular, if the lens is replaced with a DSVC equipped with a one-shot AF system tuned to a specific lens because the lens strongly depends on an optical system such as a focus lens, the lens and the DSVC main body cannot be aligned. There is a problem that it is not possible to determine an appropriate focal point.

[0007] One-shot AF using a restoration filter utilizes a characteristic called a point spread function, which is a basis for generating a restoration filter. In particular, the point image radius is the most important, but it is affected by shooting conditions such as the focal length and the aperture. If the aperture value is small, the point image radius becomes too large, and if the aperture value is large, the point image radius becomes too small. As a result, there is a problem that the range of the subject distance to which the one-shot AF can be applied is narrowed, or a phenomenon that the one-shot AF cannot be applied is caused.

In general, as the number of restoration filters increases, it becomes possible to deal with a variety of lenses with high accuracy. However, as a practical problem, the number of restoration filters is increased due to the limitation of the memory (ROM) mounted. There is a problem that it is difficult to prepare.

Further, when performing one-shot AF,
Normally, the AF area is cut out from the image frame and
Processing such as T and IFFT is performed. However, the AF area includes a permeation of a point image from outside the AF area, and the influence is particularly large in the peripheral area of the AF area. In addition, unnecessary high frequency components due to discontinuity also occur. This causes a disturbance when calculating the AF evaluation value, and has a problem in that accurate focus detection is hindered.

The present invention has been made in view of the above, and an object of the present invention is to provide an automatic focus control device capable of performing a high-speed and high-precision focusing operation.

[0011]

According to a first aspect of the present invention, an image is taken at an initial focus lens position, image data is output, and a point image radius is set for the image data. Image data is restored using a plurality of corresponding restoration filters, AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are collated to determine the focus position. In the automatic focus control device, the color information of the image data in the AF area is detected for each color component, and a specific color component responsible for calculating the AF evaluation value is determined based on the detection result. The AF evaluation value is calculated using a specific color component.

According to the first aspect of the present invention, color information of image data in the AF area is detected for each color component, and a specific color component responsible for calculating an AF evaluation value is determined based on the detection result. Since the AF evaluation value is calculated based on the determined specific color component, for example, when the color components are uniform, only the G component is used for the AF evaluation value as a substitute for the luminance signal, or the specific component is biased. If there is, the specific color component can be used when calculating the AF evaluation value, and the product-sum operation can be greatly reduced, and a high-speed automatic focus control device can be realized. .

According to a second aspect of the present invention, an image is picked up at an initial focus lens position and image data is output, and the image data is output to the image data by using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that calculates an AF evaluation value for each of image data groups restored for each restoration filter by performing restoration, and compares the calculated AF evaluation values to determine a focus position, a focusing operation is performed. Detection means for detecting a factor affecting the, and correction means for correcting the focusing operation based on the detection result of the detection means,
It is provided with.

According to the second aspect of the present invention, a factor affecting the focusing operation is detected, and the focusing operation is corrected based on the detection result. High-precision automatic focus control can be performed without being affected by the applied factors.

According to a third aspect of the present invention, an image is picked up at an initial focus lens position and image data is output, and the image data is output to the image data by using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that performs restoration and calculates an AF evaluation value for each of the image data groups restored for each restoration filter, and compares the calculated AF evaluation values to determine a focus position, A lens system having identification information for identification, a lens type determination unit for detecting the identification information to determine a lens type, and a plurality of restoration filters respectively corresponding to the plurality of lens types and corresponding to the point image radius. Storage means for storing a plurality of restoration filter groups comprising: a restoration filter group corresponding to the lens type determined by the lens type determination means in the storage means. Comprising a restoration filter designating means, and
The AF evaluation value is calculated using the specified restoration filter group.

According to the third aspect of the present invention, there is provided a lens system having identification information for identifying a lens type, a lens type identification means for detecting the identification information and identifying the lens type, and a plurality of lenses. Storage means for storing a plurality of restoration filters each comprising a plurality of restoration filters each corresponding to a point image radius, each corresponding to a kind, wherein the restoration means corresponds to the lens type determined by the lens type identification means in the storage means; Since the group is designated, it is possible to calculate the AF evaluation value by the restoration filter corresponding to the lens when the lens exchange is exchanged, and it is possible to match the lens with the main body of the automatic focus control device. As a result, highly accurate automatic focus control becomes possible.

According to a fourth aspect of the present invention, an image is taken at an initial focus lens position and image data is output, and the image data is converted from the image data using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration, and compares the calculated AF evaluation values to determine an in-focus position, When executing the automatic focusing operation in order to make the operation possible control range,
Based on constraint information on shooting conditions such as automatic exposure control, parameters such as an initial focus lens position and an aperture value that affect the point spread function are changed.

According to the fourth aspect of the present invention, when the automatic focusing operation is performed, the point is set based on the restriction information of the photographing conditions such as automatic exposure control so that the automatic focusing operation can be performed. Since the parameters such as the initial focus lens position and the aperture value which affect the image distribution function are changed, the controllable parameters such as the initial lens position and the aperture value are changed so that the one-shot AF according to the imaging conditions can be performed. The limitation on the operation can be avoided, and one shot A
The applicable range of the F operation can be widened, and the AF operation can be performed over a wide range.

According to a fifth aspect of the present invention, an image is picked up at an initial focus lens position and image data is output, and the image data is converted from the image data by using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that performs restoration and calculates an AF evaluation value for each of the image data groups restored for each restoration filter, and compares the calculated AF evaluation values to determine a focus position, Image data is restored using a restoration filter, an AF evaluation value is calculated based on the restored image data, and the calculated AF evaluation value is compared to determine an approximate focus position,
Then, near the approximate focus position, the final focus position is determined by the hill-climbing servo method.

According to the fifth aspect of the present invention, first,
Image data is restored using a restoration filter, an AF evaluation value is calculated based on the restored image data, and the calculated AF evaluation value is collated to determine an approximate focus position. Since the final focus position is determined by the hill-climbing servo method in the vicinity of the focus position, the memory capacity for storing the restoration filter can be reduced, and an inexpensive and high-precision automatic focus light control device can be realized. Becomes possible.

According to a sixth aspect of the present invention, an image is taken at an initial focus lens position and image data is output, and the image data is converted to the image data by using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that performs restoration and calculates an AF evaluation value for each of image data groups restored for each restoration filter, and compares the calculated AF evaluation values to determine a focus position, The image data is restored using the restoration filter, and the AF
AF that is a smaller area than the AF area in the area
In the evaluation value area, the AF evaluation value is calculated based on the restored image data.

According to the sixth aspect of the present invention, image data of the AF area is restored using the restoration filter,
Since the AF evaluation value is calculated based on the restored image data in the AF evaluation value area which is a smaller area than the AF area in the AF area, the calculation range of the AF evaluation value is Of these, it is possible to set an area where there is little penetration of a point image and unnecessary high frequency components, and it is possible to prevent disturbance and realize a highly accurate automatic focus control device.

[0023]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a digital still camera to which an automatic focus control device according to Embodiment 1 is applied. The digital still camera shown in FIG. 1 is roughly divided into a lens system 1 for forming a subject image on a CCD, an aperture 2, a front end unit 3 for outputting image data corresponding to the subject image, and various data processing of the image data. Image Pre-Proce
ssor (hereinafter referred to as “IPP”) unit 4 and CPUI /
F6, a CPU 7 for controlling the operation of each unit of the digital still camera, an aperture control unit 8 for controlling an aperture value (f-value) of the aperture 2, and a focus lens control unit 9 for driving and controlling a focus lens of the lens system 1. , Is provided.

The lens system 1 includes an imaging lens and a focusing 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 ASIC into digital image data and outputs the digital image data to IPP unit 4
And.

The IPP unit 4 converts the digital image data input from the front end unit 3 into RGB data.
The RGB value separation unit 41 separates the RGB components into RGB components, and the gain of each color component of the separated RGB digital signal is adjusted to adjust the luminance value generation unit 43 and the R, G, B components.
An RGB gain adjuster 42 for outputting to each of the component accumulators 51 to 53; a luminance value generator (YUV converter) 43 for converting an input RGB digital signal into a luminance signal and outputting the luminance signal to an FFT (IFFT) calculator 44 A color component detection / analysis unit 5 that performs an integration process for each color component and outputs a selection signal indicating which color component to use when calculating the AF evaluation value to an FFT (IFFT) calculation unit 44; Is provided.

The IPP unit 4 further includes a luminance signal input from the luminance value generation unit 43 or an RGB gain adjustment unit 4.
The FFT (IFFT) calculation unit 44 converts the RGB digital signal input from the FFT 2 into a frequency component, and inversely converts the signal restored by the filtering unit 45 into a spatial component. A filtering unit 45 that performs a restoration process on the signal converted to the component using a plurality of restoration filters respectively corresponding to a plurality of point image radii; And an error component (negative value component) of a signal inversely transformed into a spatial component by the FFT (IFFT) operation unit 44 by accumulating the high frequency components of the above and calculating a high frequency component integrated value and outputting the integrated value to the CPU 7.
And an error component integrator 47 for calculating a negative integrated value and outputting the calculated integrated value to the CPU 7.

As described above, the CPU 7 controls the operation of each unit of the digital still camera. Specifically, for example, the CPU 7 performs the operation based on the input high-frequency component integrated value and negative value integrated value. The CPU 7 performs AF control by calculating an AF evaluation value (a detailed calculation method of the AF evaluation value will be described later), and the CPU 7 performs AE (Auto Exposure) control, AWB (Auto White Balance) control, and the like.

The color component detection / analysis unit 5 accumulates the R, G, and B components of the RGB digital signal and outputs the accumulated R, G, and B components to a selector comparison unit 54, a G component integration unit 52, and a B component integration unit. Based on the integrated values of the unit 53, the R component integrating unit 51, the G component integrating unit 52, and the B component integrating unit 53,
When calculating the AF evaluation value, an FFT (IFFT) calculation unit 44 outputs a selection signal instructing which color component to select.
And a selector comparing unit 54 that outputs the data to the

The outline of the AF (one-shot AF) operation of the digital still camera will be described. First, CCD
RGB digital color signals obtained from the A / D converter 31 from the A / D converter 31 are input to the IPP unit 4 that performs image signal processing. In the IPP unit 4, first, the RGB digital signal is separated by the RGB separation unit 41 into R, G, and B components (RGB digital signals), and then adjusted by the RGB gain adjustment unit 42, and the luminance is adjusted. It is output to the value generation unit 43 and the color information detection unit 5. Here, the brightness value generation unit 4
Only signals within the set AF area are output to the signals 3 and the color component detection / analysis unit 5.

In the luminance value generation section 43, the input RGB
The digital signal is converted into a luminance signal, and the FFT (IFF
T) Output to the calculation unit 44. In the color component detection / analysis unit 5, the R, G, and B components of the RGB digital signal are accumulated by an R component integrator 51, a G component integrator 52, and a B component integrator 53, and each integrated value is converted into a selector comparator. It is output to 54. In the selector comparing section 54, the R component integrating section 5
1. Based on the integrated values of the G component integrating section 52 and the B component integrating section 53, a selection signal instructing which color component to select when calculating the AF evaluation value is output to the FFT (IFFT) calculating section 44. Is done.

When the color components are equal, about 60% of the luminance components have a G component, the selector comparing section 54 calculates the FFT (I) so that the AF evaluation value is calculated only with the G component.
The selection signal is output to the FFT (calculation unit) 44. On the other hand, when the integrated value is biased toward R or B, the selector comparing unit 54 outputs a selection signal to the FFT (IFFT) calculating unit 44 so as to calculate the AF evaluation value only with the R component or the B component, respectively. I do. Since the AE process is usually performed before the AF process, the integration and analysis of the color components may be performed during the AE process.

Subsequently, an FFT (IFFT) operation unit 44
Then, the conversion from the spatial component to the frequency component is performed on the luminance signal of the RGB digital signal or the specific color component signal selected by the selector comparing unit 54. Then, the filtering unit 45 performs a restoration process on the signal converted into the frequency component based on one restoration filter, and outputs the filtered signal to the high-frequency component integrator 46. With FFT (IFF
T) Output to the calculation unit 44.

The high-frequency component integrator 46 outputs a high-frequency component accumulated value obtained by accumulating a specific high-frequency component of the input signal to the CPU 7 via the CPU I / F 6.

On the other hand, the data subjected to the filtering process is again input to the FFT (IFFT) calculation unit 44, converted into a spatial component again, and output to the error component integrator 47. Here, this re-converted data (image data)
May include an error component (negative value). In the error component integrator 47, a negative value integrated value obtained by integrating negative values of the reconverted data is output to the CPU 7 via the CPU I / F6. That is, the integrated value of the high frequency component and the integrated value of the negative value corresponding to one restoration filter are stored in the CPU 7.
Will be entered.

The series of processing of filtering processing → high frequency component integrated value → IFFT → negative value integration is repeated by the number of restoration filters, and the high frequency component integrated values and negative value integrated values by the number of restoration filters are output to the CPU 7. Is done.

The CPU 7 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 example, the minimum value. Then, the corresponding focus lens position (target position) is specified using the restoration filter number corresponding to the retrieved minimum value as the focus index. Then, the CPU 7 outputs control data for instructing the focus lens control unit 9 to move the focus lens to the target position. In response, the focus lens control unit 9 drives the focus lens to the target position. With the above operation, the AF operation ends.

As described above, in the first embodiment, the color information of the image data in the AF area is detected for each color component, and the specific color component responsible for calculating the AF evaluation value is calculated based on the detection result. Is determined, and the AF evaluation value is calculated using the determined specific color component to determine the focus position. For example, when the color components are uniform, only the G component is used as a substitute for the luminance signal. If the value is used or the specific component has a bias, the specific color component can be used for calculating the AF evaluation value, and the product-sum operation for specifying the focus position can be greatly reduced. As a result, a high-speed automatic focusing operation becomes possible.

(Embodiment 2) Embodiment 2 will be described with reference to FIGS. The second embodiment detects a factor that affects the focusing operation and corrects the focusing operation based on the detection result. The lens 1 having the AF lens identification signal contact point 1x and the lens type And a lens identification unit 11 for selecting a high-frequency component range suitable for the filter.

FIG. 2 is a structural diagram showing the structure of the lens. As shown in FIG. 2, the lens has an AF lens identification signal contact 1x having a lens identification code for detecting lens replacement.

FIG. 3 is a block diagram showing the structure of the lens identification unit 11. The lens identification unit 11 is for setting a restoration filter and a high frequency setting range suitable for a lens. The lens identification unit 11 includes the lenses 1a to 1
c,.., a restoration filter group 13a composed of a plurality of restoration filters respectively corresponding to a plurality of point image radii.
To 13c,... Are respectively stored.
, And the ROM 14 storing high-frequency setting range data 14a to 14c,... Corresponding to the lenses 1a to 1c,. Then, the type of the lens is identified based on the lens identification code.
And a corresponding restoration filter group from the ROM 1
4 is provided with a selector lens identification section 12 for selecting a corresponding high frequency setting range.

The lens identification unit 11 sets a restoration filter group and a high frequency setting area each time a lens is mounted. In the digital still camera (see FIG. 1), the filtering unit 45 (see FIG. 1)
The selected restoration filter group is used as a restoration filter at the time of image restoration.
(See FIG. 1) accumulates high-frequency components in the selected high-frequency setting region to calculate a high-frequency component integrated value,
7 (see FIG. 1) calculates an AF evaluation value based on the input high-frequency component integration value and negative value integration value, and performs AF control.

As described above, in the second embodiment, the lens is provided with the lens identification code for identifying the lens type, and the lens identification section 11 detects the lens identification code to determine the lens type. Therefore, since the restoration filter group corresponding to the lens type is selected, the AF evaluation value can be calculated by the restoration filter corresponding to the lens when the lens exchange is exchanged. , And high-precision automatic focus control becomes possible.

(Embodiment 3) Embodiment 3 will be described with reference to FIG. In the third embodiment, in the digital still camera having the configuration of the first embodiment, when performing a one-shot AF operation, controllable parameters such as an initial lens position are operated to limit the applicable range of the one-shot AF operation as much as possible. An operation example in which the operation is expanded will be described.

In general, in DSVC, A
In many cases, the E processing is performed to calculate an appropriate exposure amount, and the photographing condition is set based on the calculated exposure amount. However, the point image radius is affected by imaging conditions such as the focal length and the aperture. Therefore, in the fourth embodiment, the controllable parameters such as the initial lens position are operated to expand the applicable range of the one-shot AF operation as much as possible.

FIG. 4 is an explanatory diagram for explaining the operation of controlling the parameters during the one-shot AF operation. In particular, the aperture value, the focal lens position, the point image radius and the point image radius when the subject is at a distance of 0.5 m. Shows the relationship. As shown in the figure, when the initial focus lens position is ∞, especially when the aperture value is small, for example, when the shooting condition of f6.7 is set, the point image radius becomes too large (A in the figure). ), The allowable point image radius area supported by DSVC is exceeded. On the other hand, when the aperture value is large, for example, when the shooting condition of f38 is set, the point image radius becomes too small (B in the drawing), and the proper focus position cannot be pointed out. There is. That is, depending on the aperture value and the position of the focusing lens, the range of the subject distance to which the one-shot AF can be applied may be narrowed or may not be applicable.

In the fourth embodiment, for example, when photographing conditions such as the apertures f6.7 and f38 are set, the aperture control unit 8 forcibly sets f11 only during the one-shot AF process. (A 'in the figure) and f22 (B' in the figure)
Is shifted to a condition under which one-shot operates most effectively. After that, when the one-shot AF processing is completed, the photographing conditions set in the AE are returned to, and the subsequent AWB
(White balance) processing.

Although not shown, when the portrait mode is selected, the subject is more than 10 m long.
There is hardly anything above that. Under these conditions,
When the aperture f6.7 is selected, the focus lens controller 9 sets the initial focus lens index position to the ∞ position (C in the figure).
And a position (C ′ in the figure) from the point is controlled so that the point image radius falls within the allowable range.

As described above, in the third embodiment, when the automatic focusing operation is performed, the restriction information of the photographing conditions such as the automatic exposure control is set so that the automatic focusing operation can be performed. Based on the above, parameters such as the initial focus lens position and the aperture value which affect the point spread function can be changed, so that limitations on the one-shot AF operation due to imaging conditions can be avoided. Can be widened, and a wide range of AF operations can be performed.

(Embodiment 4) Embodiment 4 will be described with reference to FIG. In the fourth embodiment, an operation example in which the one-shot AF is used for coarse adjustment and the hill-climbing servo method is used for fine adjustment in the digital still camera having the configuration of the first embodiment will be described.

In general, as the number of restoration filters increases, it becomes possible to correspond to lenses with high accuracy and various colors.
M) It is difficult to prepare a large number of restoration filters due to restrictions such as capacity. Therefore, in the fourth embodiment, the one-shot AF is used for coarse adjustment, while the hill-climbing servo method is used for fine adjustment. That is, the in-focus position is determined by using both the one-shot AF and the hill-climbing servo method.

FIG. 5 is a diagram for explaining an operation example in which the one-shot AF is used for coarse adjustment and the hill-climbing servo method is used for fine adjustment. FIG. 5 is a diagram for explaining the one-shot AF operation (see FIG. 5). A diagram for explaining the hill-climbing servo method (a diagram shown in the lower part of the figure) is shown in association with a figure shown in the upper part.

The figure for explaining the one-shot AF operation shows the relationship between the lens position, the object position, the restoration filter, and the one-shot AF evaluation value. As shown in the figure, the filtering unit 45 has a focal position of ∞ to Ne.
ar (closest), there are seven restoration filter Nos. each corresponding to each distance. 1 to No. 7 (filter group). Each restoration filter No. 1 to 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 AF evaluation value. In FIG. At 6,
The CPU 7 outputs a signal indicating that the AF evaluation value is the in-focus position to the focus lens control unit 9. Based on this signal, the focus lens controller 9 sets the focus lens to the filter No. Move to the position corresponding to 6.

Next, as shown in the figure for explaining the hill-climbing servo method, as shown in FIG. 5 and filter N
o. Between 6, the focal point is detected by the hill-climbing method. In this way, the focus lens is finally moved to a position where the subject is focused. In this embodiment, an example is described in which seven restoration filters are provided for coarse adjustment of the one-shot AF, but the number of filters is not limited to this in the present invention.

As described above, in the fourth embodiment, image data is restored using a restoration filter, an AF evaluation value is calculated based on the restored image data, and the calculated AF evaluation value is calculated. The approximate focus position is determined by comparing the values, and the final focus position is determined by the hill-climbing servo method in the vicinity of the approximate focus position, so the memory capacity for storing the restoration filter is reduced. Can be reduced,
High-precision automatic focusing operation can be performed with an inexpensive configuration.

Also, in the fourth embodiment, the high-frequency component used in the hill-climbing servo method uses the FFT engine (FFT (IFFT) calculation unit 4) used in the one-shot AF.
4 and the high frequency component integrator 46) can be used, so that a new device for the hill-climbing servo method is not required.

(Fifth Embodiment) A fifth embodiment will be described with reference to FIGS. In the fifth embodiment, in the digital still camera having the configuration of the first embodiment,
An operation example in which the calculation range of the F evaluation value is set in an area of the AF area where the penetration of a point image or an unnecessary high-frequency component is small to realize high-precision AF will be described.

Generally, when performing one-shot AF,
Normally, an AF area is set from an image frame and FFT
And processing such as IFFT. However, this AF area includes a permeation of a point image from the outside of the AF area and an unnecessary high-frequency component, and the influence is particularly large in the periphery of the AF area. The penetration of a point image from the outside of the AF area and unnecessary high-frequency components become disturbances when calculating the AF evaluation value, and hinder highly accurate focus detection. Therefore, in the fifth embodiment, the calculation range of the AF evaluation value is set in an area of the AF area where the penetration of a point image and unnecessary high-frequency components are small, thereby realizing high-precision AF.

FIG. 6 shows the AF area and the AF evaluation value area, and FIG. 7 shows the AF area and the AF evaluation value calculated in the AF evaluation value area. More specifically, as shown in FIG. 6, in the fifth embodiment, the image frame is 1280 ×
The number of pixels is 1,000. And A in the image frame
The F area is 256 × 256 pixels, and the A area in the AF area is
The F evaluation value calculation area is set to 128 × 128 pixels. FIG. 7 shows an AF evaluation value in an AF area of 256 × 256 pixels and an AF evaluation value in an AF evaluation value calculation area of 128 × 128 pixels. In FIG.
The F evaluation value is shown, and the horizontal axis shows the filter number. In addition, as shown in FIG.
In the case of 128 pixels, it is possible to calculate an AF evaluation value with higher accuracy than in the AF area of 256 × 256 pixels. The number of pixels in the image frame, the AF area, and the AF evaluation value calculation area are not limited to the above.
The point is that the AF evaluation value area should not include the vicinity of the periphery of the AF area.

As described above, in the fifth embodiment, at least a part of the image frame is set as the AF area, the image data of the AF area is restored using the restoration filter, and the image data in the AF area is restored. In the AF evaluation value area, which is a smaller area than the AF area, the AF evaluation value is calculated based on the restored image data. Therefore, the calculation range of the AF evaluation value is limited to the penetration of a point image in the AF area. It can be set in a region where unnecessary high-frequency components are small, and disturbance can be prevented, so that highly accurate automatic focusing operation can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without changing the gist of the invention.

Further, 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.

[0063]

As described above, according to the first aspect of the present invention, an image is taken at the initial focus lens position, image data is output, and a plurality of image data corresponding to the point image radius are provided for the image data. Automatically calculating the AF evaluation value for each of the image data groups restored for each restoration filter by performing restoration of the image data using the restoration filter, and collating the calculated AF evaluation values to determine the in-focus position. The focus control device detects color information of the image data in the AF area for each color component, determines a specific color component responsible for calculating the AF evaluation value based on the detection result, and determines the AF based on the determined specific color component. Since the evaluation value is calculated, for example, when the color components are uniform, only the G component is used for the AF evaluation value as a substitute for the luminance signal, or when the specific component is biased,
The specific color component can be used when calculating the AF evaluation value, and the product-sum operation can be greatly reduced, so that a high-speed automatic focus control device can be provided.

According to the second aspect of the present invention, an image is taken at the 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. In an automatic focus control device that determines a focus position by comparing each AF evaluation value, a detection unit that detects a factor that affects the focusing operation, and a correction that corrects the focusing operation based on a detection result of the detection unit Means, high-precision automatic focus control can be performed without being influenced by factors affecting the focusing operation.

According to the third aspect of the present invention, an image is taken at the 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. A lens system having identification information for identifying a lens type, and a lens type determining unit for detecting the identification information to determine the lens type in an automatic focus control device that determines a focus position by collating each AF evaluation value When,
A storage unit storing a plurality of restoration filter groups each including a plurality of restoration filters corresponding to a point image radius, each corresponding to a plurality of lens types, and the storage unit corresponding to the lens type determined by the lens type determination unit. A restoration filter designating means for designating a restoration filter group, and calculating the AF evaluation value by using the designated restoration filter. Therefore, when the lens is replaced, the AF evaluation is performed by the restoration filter corresponding to the lens. The value can be calculated, the lens can be matched with the main body of the automatic control device, and highly accurate automatic focus control can be performed.

According to the fourth aspect of the present invention, an image is taken at the 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. In an automatic focus control device that determines an in-focus position by collating each AF evaluation value, when performing an auto-focus operation to set a possible control range of the auto-focus operation, a photographing condition such as an automatic exposure control is set. Based on the constraint information,
Since parameters such as the initial focus lens position and the aperture value that affect the point spread function are changed, it is possible to avoid the limitation on the one-shot AF operation due to the imaging conditions, and to reduce the one-shot AF operation. An application range can be widened, and an automatic automatic focus control device capable of performing an AF operation over a wide range can be provided.

According to the fifth aspect of the present invention, an image is taken at the 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. In the automatic focus control device that determines the in-focus position by comparing each AF evaluation value, first, image data is restored using a restoration filter, and an AF evaluation value is calculated based on the restored image data. The approximate focus position is determined by collating the calculated AF evaluation values. Then, near the approximate focus position, the final focus position is determined by the hill-climbing servo method. It is possible to provide an inexpensive and high-precision automatic focus light control device in which the memory capacity to be stored can be reduced.

According to the sixth aspect of the present invention, an image is taken at the 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. In an automatic focus control device that determines an in-focus position by collating each AF evaluation value, image data in an AF area is restored using a restoration filter, and an AF area in the AF area that is narrower than the AF area. In the evaluation value area, AF based on the restored image data
Since the evaluation value is calculated, the calculation range of the AF evaluation value can be set in an area of the AF area where the penetration of a point image and unnecessary high frequency components are small, and it is possible to prevent disturbance and achieve high accuracy. It is possible to provide an automatic focus control device.

[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 a configuration diagram showing a configuration of a lens according to a second embodiment.

FIG. 3 is a block diagram illustrating a configuration of a lens identification unit according to Embodiment 2.

FIG. 4 is an explanatory diagram for describing an operation of performing parameter control during a one-shot AF operation according to the third embodiment.

FIG. 5 is an explanatory diagram illustrating an operation example according to a fourth embodiment in which one-shot AF is used for coarse adjustment and a hill-climbing servo method is used for fine adjustment.

FIG. 6 is a diagram showing an AF area and an AF evaluation value area according to a fifth embodiment.

FIG. 7 is a diagram showing AF evaluation values calculated in an AF area and an AF evaluation value area according to the fifth embodiment.

[Explanation of symbols]

 Reference Signs List 1 lens system 2 aperture 3 front end section 4 image preprocessor (IPP) section 5 color component detection analysis section 6 CPU I / F 7 CPU 8 aperture control section 9 focus lens control section 11 lens identification section 12 selector lens identification section 13, 14 ROM 31 CCD 32 signal processing unit 33 A / D converter 41 RGB separation unit 42 RGB gain adjustment unit 43 luminance value generation unit (YUV conversion unit) 44 FFT (IFFT) calculation unit 45 filtering unit 46 high frequency component integrator 47 error component integration Unit 51 R component integrating unit 52 G component integrating unit 53 B component integrating unit 54 selector comparing unit

Claims (6)

[Claims] An image is output at an initial focus lens position, and image data is output. The image data is restored using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, color information of image data in an AF area is detected for each color component, and the calculation of the AF evaluation value is performed based on the detection result. An automatic focus control device which determines a specific color component and calculates the AF evaluation value based on the determined specific color component. 2. An image is taken 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. The AF evaluation value is calculated for each of the image data groups restored to
In an automatic focus control device that determines an in-focus position by comparing an evaluation value, a detection unit that detects a factor that affects a focusing operation, and a correction that corrects the focusing operation based on a detection result of the detection unit Means for auto-focusing. 3. An image is taken 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. The AF evaluation value is calculated for each of the image data groups restored to
An automatic focus control device that determines an in-focus position by comparing an evaluation value, comprising: a lens system having identification information for identifying a lens type; and a lens type determination unit configured to detect the identification information and determine the lens type. A storage unit storing a plurality of restoration filter groups each including a plurality of restoration filters corresponding to the point image radius, each corresponding to a plurality of lens types; and a lens determined by the lens type determination unit in the storage unit. An automatic focus control device comprising: a restoration filter designating unit that designates a restoration filter group corresponding to a type; and wherein the AF evaluation value is calculated using the designated restoration filter group. 4. An image pickup device at an initial focus lens position and outputs image data. The image data is restored using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, when an auto-focus operation is performed, restrictions on shooting conditions such as an automatic exposure control are set so that the auto-focus operation can be performed. An automatic focus control device characterized by changing parameters such as an initial focus lens position and an aperture value which affect a point spread function based on information. 5. An image pickup device which picks up an image at an initial focus lens position, outputs image data, and restores the image data using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, first, image data is restored using the restoration filter, and an AF evaluation value is calculated based on the restored image data. Automatic focus control, characterized by determining the approximate focus position by comparing the calculated AF evaluation values, and then determining the final focus position by the hill-climbing servo method near the approximate focus position. apparatus. 6. An image pickup device at an initial focus lens position and outputs image data. The image data is restored using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, an image data of an AF area is restored using the restoration filter, and an area within the AF area that is narrower than the AF area. An automatic focus control device, wherein in the AF evaluation value area, the AF evaluation value is calculated based on the restored image data.