JP3465910B2 - Automatic focusing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focusing system, and more particularly to an automatic focusing system which enables high-speed and highly accurate automatic focusing on any subject.

[0002]

2. Description of the Related Art In recent years, automatic focusing (AF) based on a video signal obtained from an imager without using a special sensor,
Automatic exposure adjustment (AE), automatic white balance (AW
A technique for performing B) and the like by digital processing has become common. The automatic focusing method digitally integrates the high frequency component of the video signal in the focusing target area, uses the obtained value as an evaluation value indicating the degree of focusing, and maximizes this evaluation value.
This is a method of driving and controlling the F motor. The extraction of the high frequency component of the video signal is performed using a bandpass filter.

As described above, the conventional automatic focusing control is performed based on the integrated value of the high frequency component of the video signal obtained from the imager. However, in such an automatic focusing method, since a high frequency component of the video signal in the pixel direction in the horizontal direction is extracted, a high level high frequency component is obtained when the subject is a vertical line. In some cases, the high-frequency component level decreases, and in the case of a horizontal line, the high-frequency component cannot be obtained, and highly accurate focusing control cannot be performed. For example, when the subject is the vertical line A shown in FIG. 16, the video signal obtained from the imager has a sharp fall and rise as shown by A1 in FIG. 17A, and the signal after passing through the bandpass filter. Also becomes a high level like A2. However, when the subject is a diagonal line as shown in B of FIG. 16,
The imager output does not have a steep level change like B1 in FIG. 17B, but has a gentle change, so that the signal level after passing through the bandpass filter is lowered and the focusing accuracy is lowered. . Also, in the case of a horizontal line object such as C in FIG. 16, the imager output is only the DC component.
As in (C), no output appears in the bump pass filter.

[0004]

As described above, according to the conventional automatic focusing method, when the subject is close to a diagonal line or a horizontal line,
High-precision focusing control is not possible. For horizontal line subjects,
This can be solved by forming a bandpass filter for high-frequency component extraction with a vertical filter, obtaining a sharp level change as shown by D1 in FIG. 16, and obtaining a high level like D2 as a bandpass filter output. , In that case 1H
Since the delay means is required, not only the circuit configuration scale becomes large, but also a problem arises in that it is not possible to deal with a shaded object. Also, a technology has been proposed to rotate the entire optical system by an optimum angle with respect to an oblique line or a horizontal line object (Japanese Patent Publication No. 58-708), but the optical system rotation mechanism is complicated,
There is also a problem that the size becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic focusing system which enables high-speed and highly accurate automatic focusing on any subject including horizontal lines and diagonal lines.

[0006]

In order to solve the above-mentioned problems, the automatic focusing method according to the present invention uses information relating to a high frequency component in a video signal corresponding to a focusing target area as a focusing evaluation value. An automatic focusing method for performing a focusing operation by performing a focusing operation, in which information relating to a high frequency component in video information obtained by scanning the video signal in a normal horizontal scanning direction without rotating the video signal every predetermined period A focus evaluation value of 1 is set, and the video signal is set every predetermined period.
In the angle to the normal horizontal scanning direction by a predetermined angle
Rotate while changing, respectively for each of the video signal after being the rotating, obtained by scanning the normal horizontal scanning direction
Information relating to the high frequency component in the video information is used as the second focus evaluation value, and the first focus evaluation value and the second focus evaluation value are obtained at the same time every predetermined period , and both Focus evaluation
The focus operation is performed using the value . Also, focus pair
The information related to the high frequency components in the video signal corresponding to the image area is combined.
It is an automatic focusing method that performs focusing operation by using it as a focus evaluation value.
Therefore, the above video signal is passed through without rotating for a predetermined period.
High frequency components in video information obtained by scanning in the usual horizontal scanning direction
Is used as the first focus evaluation value, and the above video signal is
Each predetermined period, a predetermined angle with respect to the normal horizontal scanning direction
The frequency of each video signal rotated while changing the angle by degrees
Each of the rotated video signals is rotated in the same order.
Each obtained by scanning in the normal horizontal scanning direction
The second focus evaluation is performed on the information related to the high frequency components in these image information.
And the first focus evaluation value and the second focus evaluation value for each predetermined period.
And the in-focus evaluation value of
The focus operation was performed using the value. Furthermore,
Information related to high frequency components in the video signal corresponding to the focus area
Focusing method for performing focusing operation using as the focus evaluation value
The above-mentioned video signal is not rotated every predetermined period.
High frequency in the image information obtained by scanning in the normal horizontal scanning direction
The information relating to the component is set as the first focus evaluation value, and the video signal
For each of the above-mentioned predetermined periods with respect to the normal horizontal scanning direction
Each video signal rotated while changing the angle by
Rotate in the order that the frequency of the constant angle increases,
Scan in the normal horizontal scanning direction for each video signal
Engagement Ru information to a high frequency component in each of the video information obtained by
A second focus evaluation value is set, and the first focus evaluation value is set every predetermined period.
While simultaneously obtaining the focus evaluation value and the second focus evaluation value,
Focusing operation is performed using the focusing evaluation values of both of them.
It was

[0007]

In the present invention, the video signal is rotated every predetermined period.
Of the video information obtained by scanning in the normal horizontal scanning direction without
Information relating to the high frequency component is set as a first focus evaluation value, and the video signal is set in the normal horizontal scanning direction every predetermined period .
Rotate while changing the angle by a predetermined angle, by the rotating
For each of the video signal after the information relating to the high-frequency component in each of the image information obtained by scanning the normal horizontal scanning direction as a second focus evaluation value, the every the predetermined time period First
Tomo obtains the focus evaluation value and the second focus evaluation value at the same time
In addition, the focusing operation is performed by using the focusing evaluation values of both of them , and even if the subject image has any inclination, it is always the maximum.
It is designed so that an appropriate focusing operation can be performed. Also in the present invention
Is the normal signal without rotating the video signal every predetermined period.
It relates to the high frequency components in the video information obtained by scanning in the horizontal scanning direction.
Information as the first focus evaluation value, and the video signal
Every fixed period, there is no specified angle to the normal horizontal scanning direction.
The frequency of each video signal rotated while changing the angle is the same
Each of the video signals after being rotated in the order of
Each obtained by scanning in the normal horizontal scanning direction
The second focus evaluation is performed on the information related to the high frequency components in these image information.
And the first focus evaluation value and the second focus evaluation value for each predetermined period.
And the in-focus evaluation value of
Use the value to perform the focusing operation, and do not tilt
Optimal focusing operation is always possible even with a subject image
I am trying to do it. Further, in the present invention, the above video signal
Run in the normal horizontal scanning direction without rotation every predetermined period.
The first combination of the information related to the high frequency components in the video information obtained by the inspection
The focus evaluation value is set, and the above video signal is normally
Do not change the angle by a predetermined angle with respect to the horizontal scanning direction of
The frequency of each video signal rotated from a specific angle increases.
Rotate in order and pair with each of the video signals after the rotation.
Then, each image obtained by scanning in the normal horizontal scanning direction is
Information relating to high frequency components in the image information is used as a second focus evaluation value.
However, the first focus evaluation value and the second focus evaluation value are calculated for each predetermined period.
A focus evaluation value is obtained simultaneously with the focus evaluation value.
Use to adjust the focus and adjust the
Even if it is a subject image that is
I am sorry.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an automatic focusing system according to the present invention. In this example,
The tilted subject image video signal is electrically rotated to the optimum angle (vertical direction) to always enable highly accurate high frequency component extraction. For example, the original image shown in FIG. 2A is rotated by an appropriate angle to obtain images (B) to (F) at desired angles. In (B), the original image (A) is rotated to obtain a subject image original image having an angle surrounded by a thick frame. At this time, the shaded area is a portion that does not exist in the original image, but since the subject image exists in the substantially central portion, no problem occurs. Also, the original image portion that extends beyond the thick frame is deleted.

In FIG. 1, a subject image formed on an imager 2 such as a CCD via an optical system 1 is converted into an electric signal and input to an image pickup process circuit 3. The imaging process circuit 3 subjects the signal from the imager 2 to known signal processing, and outputs a video signal to the recording system via the terminal 4a of the switch 4. The luminance Y signal from the imaging process circuit 3 is converted into a digital signal by the A / D converter 5 and written in the field memory 6. Various synchronizing signals are generated from the SSG circuit 10 to drive the timing generator circuit 9 to control the operation of the imager 2,
The operation timing of the imaging process circuit 3 is controlled and the writing timing of the field memory 6 is controlled via the write control circuit 11. Under control of the address signal Add from the read control circuit 15, a video signal rotated by a predetermined angle is read from the field memory 6 and subjected to interpolation processing by an interpolation coefficient K, and then D The signal is converted into an analog signal by the / A converter 8 and output to the recording system via the terminal 4b of the changeover switch 4. The microcomputer 12 sends to the read control circuit 15 a control signal for rotating the subject image from the imager 2 by a predetermined angle.

FIG. 3 is a diagram for explaining a principle of obtaining a focus evaluation value based on information related to a high frequency component in one embodiment of the automatic focusing system according to the present invention. In FIG. 3 (A), # 0 is the conventional detection direction of the high-frequency component of the vertical line without rotating the original image, and # 1 is the high-frequency component of the image rotated by 45 degrees from the # 0 direction. The detection direction of # 2 is #
The detection direction of the high frequency component of the image rotated by 90 degrees from the 0 direction is shown, and # 3 shows the detection direction of the high frequency component of the image rotated by 135 degrees from the # 0 direction. The high frequency component obtained in the above # 0 direction is the first evaluation value, and the high frequency component obtained in the # 1 to # 3 directions is the second evaluation value.
Is supplied to the microcomputer 12 as the evaluation value of each.
As the second evaluation value, the order of obtaining the high-frequency components obtained in the directions # 1, # 2, and # 3 is arbitrary, and as shown in FIG. Same frequency), that is #
1- # 2- # 3- # 1- # 2 ... and the horizontal line direction (# 2) detection direction are emphasized. That is, # 1- # 2- # 3- # 2-
It may be # 1- # 2 .... In addition, in FIG.
The detection direction for detecting the second evaluation value is arbitrary, but in this example, three representative values of 45 degrees, 90 degrees, and 135 degrees are used.
Direction is used.

The Y signal converted into a digital signal by the A / D converter 5 has a high-pass component extracted by the bandpass filter 19, and the integrated value integrated by the integrating circuit 20 is a normal evaluation value (first evaluation value). (Referred to as a value) is supplied to the microcomputer 12. A high-frequency component of the signal interpolated by the interpolation processing circuit 7 is extracted by the bandpass filter 13, and the integrated value obtained by the integration circuit 14 is the microcomputer 1.
2 is supplied to the microcomputer 12 as an evaluation value (hereinafter, referred to as a second evaluation value) indicating the focus degree. Microcomputer 1
2 drives the AF motor driver 17 to perform the focusing operation based on the evaluation value. That is, the microcomputer 12
Causes the focusing operation to be performed based on one of the first evaluation value and the second evaluation value or a combination evaluation value thereof.

Referring to FIG. 4, the microcomputer 12 operates as shown in FIG.
From the first evaluation value obtained in the # 0 direction and the second evaluation value obtained in the # 1 to # 3 directions, the optimum evaluation value for the AF operation for each field based on Vsync shown in (A). Data is switched and selected. It is assumed that the subject is at an angle (tilt) position as shown in (B), and when the subject is in the vertical direction as in A, the first evaluation value (C ) Is used as a reference value for AF operation. Further, when the subject is inclined like B1 and B2, the second evaluation value (D) is used. Here, when the subject is at the position A, the second evaluation value is hardly obtained as in (D), and the subjects are B1 and B.
At the position of 2, the second evaluation value is obtained as in (D), but the first evaluation value (C) is hardly obtained.

The above embodiment shows the case of the even order switching (the case where # 1 to # 3 are repeated at the same frequency) in FIG. 3B, but an example of emphasizing the horizontal line (that is, #).
The second evaluation value obtained in 1- # 2- # 3- # 2- # 1 ...) is shown in FIG. In this case, the second evaluation value obtained by the first field of the subject B1 is in the 90-degree direction indicated by # 2, so the second evaluation value cannot be obtained, and the first evaluation value is not obtained. Since the evaluation value of 1 cannot be obtained, there is no evaluation value used for the AF operation and the result is NG. But by the next field # 1
Since the detection in the 45-degree direction indicated by is performed, an appropriate second evaluation value is obtained. In this way, an evaluation value serving as an AF operation reference cannot be obtained in a certain field, and an appropriate second evaluation value can be obtained with a succeeding field value even if the value is NG, so that rapid AF operation is possible.

The principle of address conversion for controlling the rotation of the subject image will be described with reference to FIG. Figure 5
An address positional relationship when a thick line image is obtained by oblique scanning by rotating an original image indicated by a thin line by θ is shown. In the figure, white circles represent real pixels stored in the memory, and black circles represent virtual pixels read from the memory. Each address position P
(00), P (10), P (20), P (01), P
(11), P (21), P (02), P (12), P
(22) Corresponding pixel data is written in the field memory 6, and the pixel data at these address positions are used to rotate by θ with respect to the position P (00) as the corresponding address position Q ( 10), Q (20), Q
(01), Q (11), Q (21), ... Are obtained and sent to the field memory 6 as the address signal Add.

For example, the address position Q (1
The virtual pixel addresses of 0), Q (20), Q (01), Q (11) are obtained as follows from the relationship shown in the figure. Q (10): x ... P (00) + cos θ y ... P (00) + sin θ Q (20): x ... P (00) +2 cos θ = P (10) +2 cos θ-1 y ... P (00) +2 sin θ = P (10 ) +2 sin θ Q (01): x ... P (00) -sin θ y ... P (00) + cos θ Q (11): x ... P (00) -sin θ + cos θ = P (01) -sin θ + cos θ y ... P (00) + cos θ + sin θ = P (01) + cos θ + sin θ−1

FIG. 6 shows an example of a circuit for generating the above X address. A pixel address to be read first, 0 in this example, is set in the XST register 151X, and XW
XW = cos θ shown in FIG. 5 is generated from the register 152X and X shown in FIG. 5 is generated from the X0 register 153X.
0 = −sin θ has been generated. The output of the adder 154X is delayed by one clock (for one pixel) by the delay device 156X. The adder 154X adds the cos θ from the XW register 152X and the output from the delay device 156X.
The output of the delay device 156X is added to the output (0 in this example) from the XST register 151X in the adder 158X. The delay device 157X outputs the output of the adder 155X to 1
Delay by H. The adder 155X is the X0 register 15
The −sin θ from 3X and the output from the delay device 157X are added. The adder 159X adds the output of the delay device 157X and the output of the adder 158X and outputs the result as an X address signal.

FIG. 7 shows an example of a circuit for generating a Y address signal similar to that shown in FIG. YST register 151Y
Is set to 0, and from the YW register 152Y, as shown in FIG.
YW = sin θ is generated, and Y0 register 153 is generated.
From Y, Y0 = cos θ shown in FIG. 5 is generated. The output of the adder 154Y is delayed by one clock (one pixel) by the delay device 156Y. The adder 154Y adds sin θ from the YW register 152Y and the output from the delay device 156Y. The output of the delay device 156Y is YST
The output (0 in this example) from the register 151Y is added by the adder 158Y. The delay device 157Y delays the output of the adder 155Y by 1H. Adder 155Y
Is the cos θ from the Y0 register 153Y and the delay unit 1
57Y and the output from 57Y are added. The adder 159Y adds the output of the delay device 157Y and the output of the adder 158Y and outputs the result as a Y address signal.

FIG. 8 is a diagram showing the principle of address conversion shown in FIG. 5 and the aspect ratio of 3 to 4 (768 pixels, 2 shown in FIG. 9).
(40 lines), an address conversion diagram when rotated by 30 degrees is shown. In this case, as shown in FIG. 9, one pixel has a length and width of 2.4: 1. At this time, XST = 0 XW = 0.866 X
0 = −2.4 × 0.5 YST = 0 YW = 0.5 / 2.4 Y0 = 0.8
66, and as is clear from the figure, the general formula expressing the X address Xmn and the Y address Ymn when the number of pixels is m and the number of lines is n is as follows. Xmn = XST + m * XW + n * X0 Ymn = YST + m * YW + n * Y0 For example, the address (coordinates) of the 0th line (n = 0) is (XY) = (0,0), (0.866,0.208) ，
(1.732, 0.417), ... In the first line (n = 1), (XY) = (− 1.2, 0.866), (−0.33)
4, 1.074), (0.532, 1.28), ... Here, the integer part of each address is the address Add,
It is clear from the figure that the fractional part indicates the interpolation coefficient K.

Now, referring to FIG. 1, this embodiment is also applicable to an electronic zoom operation when the zoom motor driver 16 is driven by the operation of the zoom switch 18.
FIG. 10 shows actual pixel addresses P (00), P (10), P (20), P (30), which are indicated by white circles during electronic zoom operation.
P (01), P (11), P (21), P (31),
Virtual pixel address Q (00), Q (10) after zooming,
Q (20), Q (30), Q (40), Q (01), Q
(11), Q (21), Q (31), and Q (41) are shown. At this time, XW and Y0 are constant values, and X0 and Y0 are
W is 0.

It is preferable that the four-point weighted average method as shown in FIG. 11, for example, be used for the interpolation processing for extracting the high frequency component with higher accuracy by using the band pass filter shown in FIG. The address position Q to be read from the memory is
As shown in the figure, when X1 and X2 are defined, the surrounding four points P (1
1), P (21), P (12), P (22) weighted average is used to obtain by the following formula. Q = (1-Ky) X1 + Ky * X2 X1 = (1-Kx) P (11) + KxP (21) X2 = (1-Kx) P (12) + KxP (22) Therefore, Q = (1-Kx) ( 1-Ky) P (11) + Kx (1-Ky) P (21) + Ky (1-Kx) P (12) + Kx · Ky · P (22) (1) The operation of the formula (1) is one cycle. 4 pixel address P in
This can be realized by reading (11), P (21), P (12), and P (22) at the same time. The simultaneous reading of the four pixels can be performed using a memory configuration as shown in FIG. 10, for example.

In the example shown in FIG. 12, even columns are arranged so that four pixels can be read by supplying an address once.
Even row dedicated memory (A), odd column, even row dedicated memory (B), even column, odd row dedicated memory (C) and odd column,
Four independent memories of the odd row memory (D) are provided.

FIG. 13 shows an address generating circuit for reading data from the memory for performing the arithmetic operation by the above-mentioned four-point weighted averaging circuit. An address, a column address for even column memory, a row address for odd row memory, and a row address for even row memory are generated. 0 for column address
The bits are output as the select signal HSEL and added by the adder 251 with bits 1 to 9. 1 to
9 bits become the column address for the odd column memory, and the adder 2
The output of 51 becomes the column address for even column memory. Similarly, 0 bit of the row address is output as the select signal VSEL and is added by the adder 252 with 1 to 7 bits. Bits 1 to 7 become the row address for the odd row memory, and the output of the adder 252 becomes the row address for the even row memory.

FIG. 14 shows an example of a circuit for performing the 4-point weighted average calculation shown in the equation (1) using the read data read from the memory. In FIG. 14, the selectors 253 and 254 are the selection signals HS obtained in FIG.
When EL is "H", the "H" terminal is selected, and when it is "L", the "L" terminal is selected, and the selector 261 similarly selects the corresponding terminal by the select signal VSEL. Even-numbered-column even-row read data and odd-numbered-column even-row read data are input to the selector 253, and the selector 254 receives
Even-numbered column odd-row read data and odd-numbered column odd-row read data are input. The two outputs from the selector 253 are multiplied by the coefficients (1-K
x) and Kx are multiplied. The outputs of the multipliers 255 and 256 are added by the adder 257 and output to the 2-input terminal (L, H) of the selector 261. On the other hand, the two outputs from the selector 254 are multiplied by the coefficients (1-Kx) and Kx by the multipliers 258 and 259, respectively. Multiplier 258
The outputs of and 259 are added by the adder 260 and output to the other two input terminals (L, H) of the selector 261. The two outputs from the selector 261 are X1 and X2 described above, and the multipliers 262 and 263 respectively output the coefficient (1-K
x) and Kx are multiplied. The outputs of the multipliers 262 and 263 are added by the adder 264 to obtain the interpolated data Q.

In the example of FIGS. 13 and 14, the select signal is necessary because, as shown in FIG. 15, four address points to be selected are generated in accordance with the four patterns # 1 to # 4. In this example, pattern # 2 is shown.

[0025]

As described above, according to the automatic focusing method of the present invention, it is possible to always perform high- speed and high-precision focusing control for a subject image in any tilted state.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic focusing system according to the present invention.

FIG. 2 is a diagram for explaining the principle of the automatic focusing method according to the present invention.

FIG. 3 is a diagram illustrating a principle of acquiring a focus evaluation value according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of a focus evaluation value used for a focus operation in the embodiment of the present invention.

FIG. 5 is an address generation principle diagram showing an image rotation principle in the embodiment of the present invention.

FIG. 6 is a circuit diagram for generating an X address according to the principle diagram shown in FIG.

FIG. 7 is a circuit diagram for generating a Y address according to the principle diagram shown in FIG.

FIG. 8 is a diagram showing an address generation principle when the principle shown in FIG. 5 is applied to actual image rotation.

9 is an image configuration diagram which is a basis of the principle diagram shown in FIG. 8. FIG.

FIG. 10 is a diagram showing the principle of the electronic zoom operation in the embodiment of the present invention.

FIG. 11 is a principle diagram of performing interpolation processing in an interpolation processing circuit 7 according to an embodiment of the present invention by four-point weighted average calculation.

12 is a memory configuration diagram used to perform the interpolation process shown in FIG. 11. FIG.

13 is a circuit diagram showing an example of a memory read address generation circuit used in the interpolation processing shown in FIG.

14 is a circuit diagram showing an example of the interpolation process shown in FIG.

FIG. 15 is a selected 4 in the interpolation processing shown in FIG.
It is a figure which shows the example of the even and odd combination of a point.

FIG. 16 is a diagram showing vertical, horizontal, and diagonal subject images.

17 is a diagram showing changes in high-frequency components obtained from a bandpass filter in the conventional automatic focusing method for each of the subjects shown in FIG.

[Explanation of symbols]

1 Optical System 2 Imager 3 Imaging Process Circuit 4 Changeover Switch 5 A / D Converter 6 Field Memory 7 Interpolation Processing Circuit 8 D
/ A converter 9 Trigger circuit 10 S
SG circuit 11 Write control circuit 12 Microcomputer 13,19 Bandpass filter 14,20 Integration circuit, 15 Read control circuit 16 Zoom motor driver 17 AF motor driver 18 Zoom switch

Claims (3)

(57) [Claims] 1. An automatic focusing method for performing a focusing operation by using information relating to a high frequency component in a video signal corresponding to a focus target area as a focus evaluation value, wherein the video signal is provided at predetermined intervals. In addition, the information related to the high frequency component in the video information obtained by scanning in the normal horizontal scanning direction without rotation is set as the first focus evaluation value, and the video signal is set to the normal horizontal level every predetermined period. Each of the video information obtained by scanning in the normal horizontal scanning direction with respect to each video signal after being rotated while changing the angle by a predetermined angle with respect to the scanning direction Is used as the second focus evaluation value , the first focus evaluation value and the second focus evaluation value are obtained at the same time for each predetermined period, and the focus evaluations of both are obtained. An automatic focusing method characterized by performing a focusing operation using a value . 2.High frequencies in the video signal corresponding to the focus area
Focusing operation is performed using the information related to the components as the focus evaluation value.
It is an automatic focusing method, The above video signal is not rotated at regular intervals,
Information related to high frequency components in the video information obtained by scanning in the scanning direction.
As the first focus evaluation value, The video signal is supplied in the normal horizontal scanning direction every predetermined period.
For each rotated while changing the angle by a predetermined angle
Rotate the video signals in the same order so that
Normal horizontal scanning direction for each video signal after
Related to high frequency components in each video information obtained by scanning
The information is the second focus evaluation value, The first focus evaluation value and the second focus evaluation for each of the predetermined periods.
Value is obtained at the same time, and the focus evaluation values of both are used.
Automatic focusing feature
Focusing method. 3.High frequencies in the video signal corresponding to the focus area
Focusing operation is performed using the information related to the components as the focus evaluation value.
It is an automatic focusing method, The above video signal is not rotated at regular intervals,
Obtained by scanning in the scanning direction Information related to high frequency components in the video information
As the first focus evaluation value, The video signal is supplied in the normal horizontal scanning direction every predetermined period.
For each rotated while changing the angle by a predetermined angle
Rotate the video signal in order of increasing frequency at a particular angle.
For each of the video signals after the rotation,
The height in each image information obtained by scanning in the horizontal scanning direction
The information related to the range component is the second focus evaluation value, The first focus evaluation value and the second focus evaluation for each of the predetermined periods.
Value is obtained at the same time, and the focus evaluation values of both are used.
Automatic focusing feature
Focusing method.