JP2001119623A - Focusing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain accurate and sure focusing by excluding the effect of high- frequency components due to the contrast specific to an object. SOLUTION: In this focusing device, where a focus evaluation value for every position of a focus lens 10 on the basis of a signal from a CCD 11 is calculated, the position of the focus lens, where the focus evaluation value is maximized is defined as a focus lens position and a lens drive mechanism 17 moves the focus lens 10 to the focus lens position to perform focusing, a focus evaluation area in a photographed image is divided into a plurality of target areas (pack cells), the focus evaluation value is calculated by summing partial focus evaluation values calculated by each target area, and the partial focus evaluation value is weighted on the basis of the signal from the CCD 11 with respect to the addition. The partial focus evaluation value related to the target areas especially suitable for the focus evaluation among a plurality of the target areas is emphasized, and then the focusing can accurately and surely be executed, even in the case that the contrast of the object OB is low or a plurality of kinds of objects OB with different contrasts are mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a focusing device used for an imaging device such as an electronic still camera.

[0002]

2. Description of the Related Art Conventionally, a focusing system in a video camera employs a focusing system commonly called a "hill climbing servo system". This hill-climbing servo system utilizes the property that when an image is in focus, high-frequency components included in electric signals from photoelectric conversion elements such as CCDs and CMOSs are larger than when the image is in a so-called out-of-focus state. ing. That is, it is determined that the image is focused at the lens position where the amount of the high-frequency component is maximum.

In order to find the lens position where the amount of high-frequency components becomes maximum, the focus lens is moved in one direction from infinity or the closest. During the movement of the focus lens, a focus evaluation area set in a part of the image is moved. , The focus evaluation value serving as an index of the high-frequency component amount is continuously calculated. As long as the focus evaluation value increases, the movement of the focus lens is continued. When a decrease in the focus evaluation value is detected, it is determined that the peak value has been exceeded, and the focus lens is returned to the lens position that establishes the maximum value.

[0004]

However, the amount of high frequency components differs depending on the inherent contrast of the subject.
An object having a low contrast has few high-frequency components, and an object having a high contrast contains many high-frequency components. For this reason, when the contrast of the subject is low, the peak of the maximum value cannot be clearly detected even by the above-described hill-climbing method, and there is a problem that accurate focusing is difficult. Further, when there is a low-contrast subject at a position close to the device and a high-contrast subject at a position far from the apparatus, there is a disadvantage that the focus tends to go to a position far from the apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to eliminate the influence of high-frequency components caused by the inherent contrast of a subject, thereby achieving accurate and reliable focusing. It is to provide a device.

[0006]

According to a first aspect of the present invention, there is provided a focus lens, a conversion element for converting light incident through the focus lens into a signal, lens driving means for moving the focus lens,
Focus evaluation value calculation means for calculating a focus evaluation value for each focus lens position based on a signal from the conversion element, and lens position specification means for specifying a focus lens position at which the focus evaluation value is maximum as a focus lens position. The lens driving means,
In a focusing device for moving a focusing lens to a focusing lens position specified by a lens position specifying unit, the focus evaluation value calculating unit includes a plurality of regions of interest, and a partial focus evaluation value calculated for each region of interest is calculated. Calculating a focus evaluation value by the addition, and weighting the partial focus evaluation value of at least one of the partial focus evaluation values of the plurality of attention regions with respect to the addition based on the signal. Is a focusing device.

In the first aspect of the present invention, when the focus evaluation value calculating means calculates the focus evaluation value for each focus lens position based on the signal from the conversion element, the lens position specifying means sets the focus at which the focus evaluation value becomes the maximum. The lens position is specified as the focusing lens position. Then, focusing is performed by the lens driving unit moving the focusing lens to the focusing lens position specified by the lens position specifying unit. Here, in the first aspect of the present invention, the focus evaluation value calculating means includes a plurality of attention areas, calculates a focus evaluation value by adding partial focus evaluation values calculated for each attention area, and relates to the addition. , Based on the signal, the partial focus evaluation value of at least one of the partial focus evaluation values of the plurality of attention areas is weighted. Emphasis is placed on the partial focus evaluation value relating to the attention area particularly suitable for evaluation, so that accurate and reliable focusing can be performed even when the contrast of the subject is low or when a plurality of types of subjects having different contrasts are mixed. Becomes possible.

According to a second aspect of the present invention, in the focusing apparatus according to the first aspect of the present invention, the focus evaluation value calculating means includes a maximum unit in the unit area based on outputs of the plurality of unit areas in the attention area. Each of the area outputs is detected, and a value obtained by dividing the sum of the maximum unit area outputs in the area of interest by the sum of outputs of the plurality of unit areas in the area of interest is a partial focus evaluation value for the area of interest. A focusing device.

In the second aspect of the present invention, the focus evaluation value calculating means detects the maximum unit area output in the unit area based on the outputs of the plurality of unit areas in the area of interest, and detects the maximum unit area output in the area of interest. Since the value obtained by dividing the sum of the maximum unit area outputs by the sum of the outputs of the plurality of unit areas in the attention area is used as the partial focus evaluation value for the attention area, the subject in the attention area regardless of the illuminance of the subject Can be detected sharply, focusing can be performed accurately even when the contrast of the subject is low, and when the brightness changes before and after the movement of the focusing lens (for example, when the cloud gradually covers And flicker of a fluorescent lamp) can also eliminate the effect.

According to a third aspect of the present invention, in the focusing apparatus according to the first or second aspect of the present invention, the focus evaluation value calculating means includes a partial focus calculated for each of the plurality of regions of interest and each focus lens position. A focusing device that corrects a partial focus evaluation value that is a maximum value among evaluation values to a predetermined value, and corrects a partial focus evaluation value other than the maximum value by the correction ratio.

According to a third aspect of the present invention, the maximum partial focus evaluation value among the partial focus evaluation values calculated for each of a plurality of regions of interest and for each focus lens position is corrected to a predetermined value. Since the partial focus evaluation value other than the maximum value is corrected by the ratio, even if the illuminance differs for each attention area, the part continuously calculated with the movement of the focus lens between the closest distance and infinity The focus evaluation value is leveled as a ratio to the maximum value corrected to the predetermined value. Therefore, in the third aspect of the present invention, it is possible to simply compare the change in the partial focus evaluation value for each attention area due to the movement of the focus lens regardless of the difference in the illuminance for each attention area, and An attention area having a large change, that is, an attention area to be emphasized for focusing can be easily specified.

According to a fourth aspect of the present invention, in the focusing apparatus according to the third aspect of the present invention, when the minimum value among the corrected partial focus evaluation values is large, the evaluation weight of the attention area is reduced. Is a focusing device.

According to a fourth aspect of the present invention, when the minimum value among the partial focus evaluation values corrected according to the third aspect of the present invention is large, the evaluation weight of the attention area is reduced. Here, in a state where the partial focus evaluation value continuously calculated with the movement of the focus lens is leveled as a ratio to the maximum value corrected to the predetermined value, the fact that the minimum value is large means that the maximum value is the maximum value. This means that the difference between the partial focus evaluation value due to the movement of the focus lens is small. Therefore, in the fourth aspect of the present invention, the attention area to be emphasized for focusing can be accurately specified by weighting such an attention area with a small weight.

According to a fifth aspect of the present invention, in the focusing apparatus according to the second, third or fourth aspect of the present invention, the partial focus evaluation value calculated for each of the plurality of regions of interest and for each focus lens position is determined by the focus. When the number of peaks formed along with the movement of the lens is large, an evaluation weight of the attention area is reduced.

According to a fifth aspect of the present invention, when the partial focus evaluation value calculated for each of a plurality of regions of interest and for each focus lens position has a large number of peaks formed as the focus lens moves,
The evaluation weight of the attention area is reduced. Here, the fact that the partial focus evaluation value has a large number of peaks formed with the movement of the focus lens means that there is a high possibility that the focus lens position indicating a small maximum value is mistaken for the focus lens position indicating the maximum value. Means Therefore, in the fifth aspect of the present invention, the attention area to be emphasized for focusing can be accurately specified by weighting such attention area with a small weight.

According to a sixth aspect of the present invention, in the focusing apparatus according to the first aspect of the present invention, the focusing apparatus further includes a band-pass filter for filtering the component of the incident light according to a frequency, and the incident light filtered by the band-pass filter. When the maximum value of the partial focus evaluation value based on the output when the component is low frequency is small, the evaluation weight for the partial focus evaluation value when the component of the incident light filtered by the bandpass filter is high frequency is reduced. A focusing device.

In the sixth aspect of the present invention, when the maximum value of the partial focus evaluation value based on the output when the component of the incident light filtered by the band-pass filter has a low frequency is small, the light is filtered by the band-pass filter. The evaluation weight for the partial focus evaluation value when the component of the incident light has a high frequency is reduced. Here, if the peak is not clearly seen when the low frequency is filtered as the pass band, the peak of the partial focus evaluation value is also located at the in-focus position of the focus lens even when the high frequency is filtered as the pass band. It has been empirically known that the reliability of the correct response is low. Therefore, in the sixth aspect of the present invention, the attention area to be emphasized for focusing can be accurately specified by weighting such attention area with a small weight.

[0018]

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

FIG. 1 shows the overall configuration of an electronic still camera to which the automatic focusing device according to the present invention is applied. The electronic still camera SC includes a focus lens 10 that captures the subject OB at an appropriate lens position, and a CCD 11 as a photoelectric conversion element that converts an image formed through the focus lens 10 into an electric signal corresponding to the illuminance. A color filter (not shown) is attached to the CCD 11. CCD11
The image captured by the A / D converter 2 of the signal processing unit 19
Recording media 1 such as a memory card
3 recorded.

The CCD driver 16 is a driver for a photoelectric conversion element, and supplies a driving signal to the CCD 11. The lens drive mechanism 17 includes a motor and a gear mechanism (not shown), and moves the focus lens 10 forward and backward (far and near) along the optical axis. The controller 18 includes a microcomputer as a main component, and an RO (not shown)
An M and a RAM are provided to control the entire apparatus including the CCD driver 16 and the lens driving mechanism 17.

Under the control of the controller 18, a current having a magnitude corresponding to the illuminance of each pixel of the image is output from the CCD 11 as a serial signal sequence in accordance with a drive signal from the CCD driver 16. The signal sequence output from the CCD 11 is supplied to a focus evaluator 20 through a signal processing unit 19. The focus evaluator 20 calculates a focus evaluation value reflecting the amount of high frequency components included in the signal sequence. The controller 18 moves the focus lens 10 to a lens position at which the focus evaluation value shows the maximum value under the control of the CCD driver 16 and the lens driving mechanism 17.

The signal processing section 19 includes an amplifier 21 for amplifying the electric signal from the CCD 11, an A / D converter 22 for linearly converting the amplified electric signal into a digital signal, and an A / D converter 22.
A digital filter for filtering a digital signal from the D converter and passing an electric signal in a desired frequency band; The A / D converter 22 outputs a linear digital signal with respect to the input light to the CCD 11. The digital value of each pixel that has passed through the digital filter 23 is summed up by the focus evaluator 20 for the entire focus area FA (see FIG. 3) as a focus evaluation area that has been set, according to a procedure described later. Is output as the focus evaluation value.

The controller 18 includes the digital filter 2
Filter coefficient setting unit 24 for setting the filter coefficient of No. 3
And a step of changing a movement step width as a distance between lens positions for moving the focus lens 10 in conjunction with an operation of a focus area setting unit 25 that divides a focus area FA into a part of an image and a lens driving mechanism 17. And a width setting unit 26. The operations of the filter coefficient setting unit 24, the focus area setting unit 25, and the step width setting unit 26 are controlled by the control execution unit 27 based on the focus evaluation value sent from the focus evaluator 20.

The filter coefficient setting section 24 changes the characteristics of the digital filter 23, that is, the pass frequency band, by arbitrarily setting the filter coefficient of the digital filter 23. For example, when the digital filter 23 is configured by two second-order IIR (infinite impulse response) systems cascaded with each other, the digital filter 23 can be configured by appropriately setting the coefficients of the respective multipliers in the configuration. It operates as a wide-pass filter having the frequency characteristic shown in FIG. 2A, operates as a high-pass filter having the frequency characteristic shown in FIG. 2B, or has a frequency shown in FIG. It operates as a low-pass filter exhibiting characteristics. Filter coefficient setting unit 24
May be provided with a table in which filter coefficients required to obtain a desired frequency characteristic are set in advance.

The focus area setting section 25 causes the focus evaluator 20 to extract only pixel signals corresponding to the focus area FA from the signal sequence. At this time, as shown in FIG. 3, the focus area FA set at the center of the photographing screen 30 is further divided into nine paxels P of 3 rows × 3 columns as a region of interest. For this division, for example, a pixel clock counter is used. As described later, each paxel P has a weight coefficient of WL1, WL2, WH1, WH2, and WH3, respectively. In the present embodiment, a configuration in which one focus area FA is set at the center of the shooting screen for easy understanding will be described. However, instead of such a configuration, a configuration in which a plurality of focus areas FA are set may be adopted. Good.

The step width setting unit 26 sets the moving step width of the focusing lens 10 based on the depth of field detected by a depth of field detecting unit (not shown). The depth-of-field detection unit detects the depth of field based on the focal length of the focus lens 10 and the aperture.

The operation of the focusing apparatus according to the present embodiment having the above-described configuration will be described below with reference to the flowchart shown in FIG. Here, the process after the step width setting unit 26 sets the moving step width of the focus lens 10 based on the depth of field detected by the depth of field detection unit will be described.

First, in a state where the focusing lens 10 is arranged at an infinity position, the controller 18 controls the CCD driver 1.
The drive output to the CCD 11 is performed through 6, and the photographing is executed (S1). The signal from the CCD 11 is amplified by an amplifier 21 and then converted into a digital signal by an A / D converter 22. Here, if the color filter of the CCD 11 is a primary color Bayer array, the output signal is a signal of an array such as GRGR BGBG GRGR BGBG (R: Red, G: Green, B: Blue). The signal is an array signal such as YCYC MGMG YCYC MGMG or YCYC MGMG YCYC GMGM (C: Cyan, M: Magenta, Y: Yellow, G: Green). Therefore, in the case of the primary color Bayer array, luminance information can be obtained from, for example, only G pixel information, and in the case of a complementary color filter, luminance information can be obtained by adding two pixels on the left and right.

Next, using the obtained luminance information, a partial focus evaluation value of each paxel P for the lens position is calculated (S2). The calculation process of the partial focus evaluation value will be described with reference to the flowchart of FIG.

In FIG. 5, first, an added value D1 of each paxel P of output data is calculated (S11). This addition value D1 increases as the brightness of the subject increases.

Next, the output data is passed through a low-pass filter to obtain an absolute value, a maximum value is obtained for each line in the paxel P, and this maximum value is added for each paxel P to obtain an added value DL
1 is obtained (S12). This addition value DL1 is larger as the maximum value when the luminance of each line is passed through the low-pass filter is larger, that is, as the paxel P contains more high-frequency components (there are many edges where the contrast changes greatly). Value.

Next, the added value D obtained in step S12
The partial focus evaluation value DL2 of each paxel P is calculated by dividing L1 by the addition value D1 obtained in step S11 (S13).

Next, the same operation is performed for the high frequency range. That is, the output data is first passed through a high-pass filter to obtain an absolute value, a maximum value is obtained for each line in the paxel P, and this maximum value is added for each paxel P to obtain an added value D
H1 is obtained (S14). Then, the obtained addition value DH
1 is divided by the addition value D1 obtained in step S11 to calculate the partial focus evaluation value DH2 of each paxel P (S15), and this routine ends.

Referring again to FIG. 4, it is determined whether the above calculation of the partial focus evaluation value has been completed ten times (S3). If the determination is negative, the moving step width set by the step width setting unit 26 is determined. The focus lens 10 is moved only by the distance (S4), and the processes of steps S1 to S3 are repeated. Thereby, the focus lens 10 is moved stepwise from infinity to the closest distance. At each stage of this movement, the addition value D1 and the addition value D
L1, partial focus evaluation value DL2, addition value DH1, and partial focus evaluation value DH2 are calculated. Note that, instead of the configuration in which the photographing is performed while the focus lens 10 is stopped, a configuration in which the photographing is performed ten times while moving may be adopted. In addition, the number of times of shooting is set to 10 as an example. The number of times of shooting may be any number, and the number of times of shooting may be determined according to the depth of field.

After the photographing and the calculation have been performed ten times in this manner, the process proceeds to step S5. Here, for ease of understanding, of the nine paxels P shown in FIG. First, in step S5, the ten partial focus evaluation values DL2 and the ten partial focus evaluation values DH2 calculated for the paxel P are divided by the maximum value of each of the ten data, and the maximum value is 1 Normalize to become
(S5). The normalized partial focus evaluation values are set to FVL and FVH, respectively.

Next, a calculation is performed on these FVL, FVH, and the like to obtain a weight W for use in calculating a weighted sum described later.
L1, WL2, WH1, WH2 and WH3 are calculated (S6). This will be described below.

[Calculation of Weights WL1 and WH1] With respect to FVL which is a normalized value, the minimum value among the ten values is adopted as an index, and WL1 is determined based on this. Specifically, WL1 is reduced as the minimum value is increased (see FIG. 6). For FVL, which is a value normalized with the maximum value as 1, the larger minimum value means that the difference between the maximum value and the minimum value is smaller, that is, the focus lens 10
Means that the change of the partial focus evaluation value FVL due to the movement of is small. Therefore, by paxel P having such a small weight, it is possible to accurately specify the paxel P to be emphasized for focusing. On the other hand, similarly, for FVH, the minimum value among the ten values is adopted as an index, and WH1 is determined based on this.

[Calculation of Weights WL2 and WH2] WL2 is
The partial focus evaluation value FVL calculated for each focus lens position is a value that decreases when the number of peaks formed with the movement of the focus lens 10 is large. The fact that the number of peaks formed by the partial focus evaluation value FVL with the movement of the focus lens 10 is large indicates that it is highly likely that a focus lens position showing a small local maximum value is mistaken for a focus lens position showing a maximum value. means. Therefore, by weighting such paxels P small, it is possible to accurately specify paxels P to be emphasized for focusing.

Note that there are several methods for detecting the number of peaks. For example, as shown in FIG.
When looking at the values of 0 FVHs in order, the value takes 1 and then decreases once by dividing Threshold 1 and then again T
When hreshold 2 is exceeded, the number of peaks is counted as two. Furthermore, when the number of peaks exceeds Threshold 2 again after being decreased by dividing by Threshold 1, the number of peaks is counted as 3.

Then, WL2 is calculated so that WL2 becomes small when the count value of the peak number is large (see FIG. 8). On the other hand, for FVH, WH
2 is calculated.

[Calculation of Weight WH3] Step S1
WH3 is calculated based on the addition value DL1 calculated in Step 2. Here, the addition value DL1 is a predetermined threshold Th
If the value falls below reshold 3, WH3 is reduced. This is because, in the signal filtered by the low-pass filter, the sum value DL1 per paxel of the maximum value per paxel line is obtained.
Is low, the added value D accompanying the movement of the focus lens 10
The peak of L1 does not clearly appear, and in such a case, even if the high frequency is passed as a pass band, the reliability of whether or not the peak of the partial focus evaluation value correctly corresponds to the focus position of the focus lens 10 is high. This is because it is empirically known that it is low. Therefore, by weighting such paxels P small, it is possible to accurately specify paxels P to be emphasized for focusing.

The weights WL1 and W thus calculated
Using L2, WH1, WH2, and WH3, the calculation of the weighted sum FV for each lens position is executed by the following equation (S7).

FV = FVL * WL1 * WL2 + FVH * WH1 * WH2 * WH3 (1) Thus, a weighted sum FV for the upper left paxel P of interest is calculated, and this calculation is performed for each lens position. By executing, the upper left paxel P is 1
Zero weighted sums FV are calculated.

Further, the same operation is performed for each paxel P, and a weighted sum FV for each of ten lens positions is obtained for each of nine paxels P. Finally, 1
For each of the zero lens positions, the sum FVtotal of the FVs for nine paxels is calculated by the following equation.

FVtotal = ΣFV (2) Then, 10 FVs obtained for each lens position
Using the total as the focus evaluation value, the focus lens position at which this FVtotal is maximum is specified as the focus lens position (S
8).

Finally, a lens drive output is performed on the lens drive mechanism 17 so that the lens 10 moves to the specified focus lens position (S9), and this routine ends.

As described above, in this embodiment, the focus area FA, which is the focus evaluation area, is divided into a plurality of paxels P, and the focus evaluation values DL2 and DH2 calculated for each paxel P are added to obtain the focus evaluation value. And the weights WL1, WL2, WH1, WH2, and WH for each of the partial focus evaluation values DL2 (DH2) related to the plurality of paxels P, based on the output signal.
Since the weighting is performed by H3, the partial focus evaluation value DL2 (DH2) of the paxel P particularly suitable for focus evaluation is emphasized from among the plurality of paxels P, whereby the contrast of the subject OB is reduced. Even when the object OB has a low contrast or a plurality of types of objects OB having different contrasts,
Focusing can be performed accurately and reliably.

In this embodiment, the maximum value in the attention area (paxel P) including the unit area (each line) is determined based on the output of the plurality of unit areas (each line in the paxel P) in the paxel P. At the same time, the partial focus evaluation value DL2 (DH2) of the paxel P is obtained by dividing the value obtained by dividing the maximum value DL1 (DH1) of each paxel P by the total sum D1 of the output data of the paxel P.
Therefore, regardless of the illuminance of the object OB, the object OB
Can be detected sharply, focusing can be performed accurately even when the contrast of the object OB is low, and when the brightness changes before and after movement of the focusing lens 10 (for example, gradually In the case of a cloud, or in the case of flicker of a fluorescent lamp), the influence can be eliminated. Instead of such a configuration, for example, the sum of the absolute values of the output through the high-pass filter is calculated for each paxel P, or a configuration in which the value is divided by the brightness, the appropriate partial focus evaluation value can be obtained. And such a configuration is also included in the scope of the present invention.

In this embodiment, a plurality of paxels P
A partial focus evaluation value DL2 (DH2) other than the maximum value, based on the maximum partial focus evaluation value DL2 (DH2) of the partial focus evaluation values DL2 (DH2) calculated for each focus lens position. Is normalized (S5),
Even when the illuminance differs for each paxel P, the partial focus evaluation value DL2 (DH2) continuously calculated with the movement of the focus lens 10 is leveled as a ratio to the maximum value. Therefore, in the present embodiment, regardless of the difference in the illuminance for each paxel P, the change in the partial focus evaluation value DL2 (DH2) for each paxel P due to the movement of the focus lens 10 can be simply compared, and the partial focus can be compared. Evaluation value DL2
It is possible to easily specify a paxel P having a large change in (DH2), that is, a paxel P to be emphasized for focusing.

In this embodiment, the weighting is performed on all the paxels P in the focus area FA. However, instead of such a configuration, the weighting may be performed on only some of the paxels P. With a configuration in which weighting is performed on at least one paxel P among a plurality of paxels, it is possible to obtain a considerable effect unique to the present invention.

In this embodiment, the focus area FA is set at the center of the photographing screen 30 as shown in FIG. 3, but the focus area FA may be set at any position on the photographing screen 30. A configuration in which the photographer can arbitrarily set the position of the focus area FA in the shooting screen 30 or a configuration in which the focus area FA automatically moves by tracking a specific subject OB. In the present embodiment, the focus area FA is divided into nine paxels P. However, the number of paxels P may be any number. It belongs to the category of the invention.

In this embodiment, the electronic still camera S
Although an example in which the present invention is applied to C has been described, the present invention can be widely applied to video cameras and various optical devices.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an electronic still camera to which a focusing device according to an embodiment of the present invention is applied.

FIG. 2 is a graph showing three different characteristics of a digital filter.

FIG. 3 is a schematic diagram showing an arrangement of a focus area and a paxel on a shooting screen.

FIG. 4 is a flowchart showing a focusing process.

FIG. 5 is a flowchart showing a process of calculating a partial focus evaluation value.

FIG. 6 is a graph showing a calculation process of a weight WL1.

FIG. 7 is a graph showing a process of detecting the number of peaks of the partial focus evaluation value FVL for calculating the weight WL2.

FIG. 8 is a graph showing a calculation process of a weight WL2.

[Explanation of symbols]

10 focus lens, 11 CCD, 16 CCD driver, 17 lens drive mechanism, 18 controller, 23
Digital filter, 30 shooting screen, FA focus area, P paxel.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Manabu Kiriri F-term (reference) 2H011 AA03 BA31 BB04 CA21 2H051 AA00 BA47 CE09 CE14 in Eastman Kodak Japan Co., Ltd. 4-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo DA03 DA19 DA23 DA26 FA48 5C022 AA13 AB29 AB30 AC42 AC54 AC69 AC74

Claims (6)

[Claims] A focus lens; a conversion element for converting incident light passing through the focus lens into a signal; lens driving means for moving the focus lens; and a focus evaluation value for each focus lens position based on a signal from the conversion element. A focus evaluation value calculating means for calculating the focus evaluation value, and a lens position specifying means for specifying a focus lens position at which the focus evaluation value becomes the maximum as a focusing lens position, wherein the lens driving means controls the focusing specified by the lens position specifying means. In a focusing apparatus for moving a focus lens to a lens position, the focus evaluation value calculation unit includes a plurality of attention areas, and calculates a focus evaluation value by adding a partial focus evaluation value calculated for each attention area. Regarding the addition, based on the signal, based on the signal, a partial focus evaluation value of at least one of the partial focus evaluation values of the plurality of attention regions A focusing device for performing weighting. 2. The focusing apparatus according to claim 1, wherein the focus evaluation value calculating unit detects a maximum unit area output in the unit area based on outputs of a plurality of unit areas in the attention area. And a value obtained by dividing the sum of the maximum unit area outputs in the attention area by the sum of outputs of the plurality of unit areas in the attention area as a partial focus evaluation value for the attention area. Focusing device. 3. The focusing apparatus according to claim 1, wherein the focus evaluation value calculation unit calculates a maximum of the partial focus evaluation values calculated for each of the plurality of regions of interest and for each focus lens position. A focusing device that corrects a partial focus evaluation value as a value to a predetermined value and corrects a partial focus evaluation value other than the maximum value by the correction ratio. 4. The focusing apparatus according to claim 3, wherein when the minimum value among the corrected partial focus evaluation values is large, the evaluation weight of the attention area is reduced. Matching device. 5. The focusing apparatus according to claim 2, wherein a partial focus evaluation value calculated for each of the plurality of regions of interest and for each focus lens position is formed as the focus lens moves. When the number of peaks to be performed is large, the evaluation weight of the attention area is reduced. 6. The focusing apparatus according to claim 1, further comprising a band-pass filter that filters the component of the incident light according to a frequency, wherein the component of the incident light filtered by the band-pass filter is a low-frequency component. When the maximum value of the partial focus evaluation value based on the output in the case of is small, the evaluation weight for the partial focus evaluation value when the component of the incident light filtered by the bandpass filter is a high frequency is reduced. Focusing device.