JP5980166B2 - Imaging apparatus and autofocus control method - Google Patents

Description

  The present invention relates to a technique for autofocus control of an imaging apparatus.

  A function that automatically adjusts the focus, that is, an autofocus (AF) function, is mounted on video cameras, HDD (Hard Disc Drive) cameras, electronic still cameras, and imaging devices of camera mechanisms of mobile phones. Hereinafter, autofocus may be described as AF.

  As a focusing method of the AF function, there is a contrast method in which focus adjustment is performed by utilizing the fact that the position where the contrast signal of the photographed image is maximized is in a focused (just focus) state. The contrast signal is calculated based on a cumulative value of differences in luminance signal values between adjacent pixels. As a contrast method, for example, there is a method described in Patent Document 1. In Patent Document 1, the amount of the frequency component included in the image signal is calculated as the AF evaluation value by utilizing the fact that the amount of the frequency component (excluding the DC component) included in the image signal is maximized at the in-focus position. A technique for controlling the position of the focus lens in a focused state where the AF evaluation value is maximized is disclosed.

Japanese Patent Laid-Open No. 3-1668

However, in the technique described in Patent Document 1, since there is one region for generating the AF evaluation value, the AF evaluation value hardly changes when a person existing in the region moves within the region. Become. Further, the fact that the AF evaluation value hardly changes means that the person cannot be recognized that the person has moved, and there is a problem that control for focusing on the person cannot be executed. As a result, a phenomenon called defocus may occur.
Accordingly, an object of the present invention is to provide a technique for improving the focusing accuracy during autofocus control.

In order to solve the above problems, an imaging apparatus of the present invention includes an area setting unit that sets two or more areas in an imaging screen, a VF value generation unit that generates a contrast signal value of the area for each area, For an area where the luminance signal value of the area satisfies a predetermined range, an AF evaluation value generating unit that adds the contrast signal value of the area and outputs the addition result as an AF evaluation value; and the AF evaluation value is maximum A focus position control unit that controls a focus lens position in a direction, and after the focus lens position where the AF evaluation value is maximized is determined, the region setting unit subdivides the region into two or more small regions. The VF value generation unit generates a contrast signal value for the small area, generates a contrast signal value for the entire area of the imaging screen, and generates the focus position. The control unit is configured such that the absolute value of the difference between the current contrast signal value and the previous contrast signal value is less than a first threshold with respect to the entire region, and the current contrast signal value and the previous contrast signal value with respect to the small region. If the absolute value of the difference from the contrast signal value is greater than or equal to the second threshold value, the contrast signal value of the small region in which the direction in which the contrast signal value of the small region increases with respect to the focus lens position is the same is added. The subtotal value is calculated, the maximum value of the subtotal values in different directions is compared, and the focus lens position is controlled in the direction of the larger subtotal value .

  ADVANTAGE OF THE INVENTION According to this invention, the technique which improves the focusing precision at the time of autofocus control can be provided.

It is a figure which shows the function example of an imaging device. It is a figure which shows the example of a processing flow of an imaging device. It is a figure which shows the continuation of the example of a processing flow of an imaging device. It is a figure which shows the example of arrangement | positioning of VF value production | generation area | region. It is a figure which shows an example of VF value. It is a figure which shows an example which masked the area | region where VF value does not satisfy | fill a threshold value, and subdivided the center area | region further. It is a figure which shows the case where the slope of the curve of AF evaluation value is positive.

  Here, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as appropriate.

First, an example of functions of the imaging apparatus 100 will be described with reference to FIG.
The imaging apparatus 100 includes the control unit 10, the lens unit 20, and the camera signal processing unit 40 as functions.

  The lens unit 20 includes a variator lens group 23 that performs zooming of a light beam from a subject, a diaphragm 24 for adjusting the amount of received light, and a focus lens group (hereinafter also referred to as a focus lens) 25 that is used for focus adjustment. And has a function of forming an optical image of a subject on a light receiving surface of an image sensor 31 constituted by a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like. Further, the lens unit 20 includes an absolute position detection unit 21 and a temperature detection unit 22 that are configured by, for example, a photo interrupter. The absolute position detection unit 21 detects the absolute positions of the variator lens group 23 and the focus lens group 25 and outputs the detection result to the control unit 10 as lens absolute position information. Moreover, the temperature detection part 22 detects the temperature in the lens unit 20, and outputs a detection result to the control part 10 as lens unit internal temperature information.

  The image sensor 31 photoelectrically converts the optical image of the subject imaged on the light receiving surface and outputs the obtained image signal to the noise removing unit 32. The noise removal unit 32 performs noise removal processing on the received imaging signal. The AGC (automatic gain control) 33 amplifies the imaging signal to an optimum level. The AD (analog / digital) converter 34 digitally converts the imaging signal into a digital imaging signal, and outputs the digital imaging signal to the camera signal processing unit 40. The electronic shutter 35 adjusts the exposure time for the image sensor 31. The GYRO sensor 36 has a function of detecting the movement of the main body of the imaging apparatus 100 and outputs how it moves to the control unit 19 as a GYRO signal.

  The camera signal processing unit 40 includes a signal conversion processing unit 41, VF value generation units 42 a to 42 n (hereinafter, reference numeral 42 is used unless otherwise distinguished), an AE (auto iris) signal generation unit 45, and high / low luminance count counting. 46a to 46n (hereinafter, reference numeral 46 is used unless otherwise distinguished).

  The signal conversion processing unit 41 performs predetermined signal processing on the received digital imaging signal, and conforms to a predetermined television system such as NTSC (National Television Standards Committee) standard or PAL (Phase Alternating Line) standard, for example. It has a function of converting to a standard television signal and outputting the television signal. The signal conversion processing unit 41 has a function of setting two or more areas in the television signal imaging screen and separately outputting the signals of the respective areas. Note that the size and setting position of the area are instructed by the control unit 10.

  Each of the VF value generation units 42a to 42n includes an HPF (high pass filter) 43 and an integration unit 44, generates a contrast signal (VF: Value of Focus) value for each region, and obtains the obtained VF values (VFa to VFn). It has a function of outputting to the control unit 10. Since the VF value generation unit 42 operates by the number of regions, reducing the number of regions has an effect of reducing power consumption.

The AE signal generation unit 45 has a function of outputting the auto iris signal AE to the control unit 10.
Each of the high and low luminance number totaling units 46a to 46n totals the number of pixels of the luminance signal value exceeding the threshold value for determining bright and the threshold value for determining dark for each region, and outputs the obtained luminance number (BNa to BNn) signals. It has a function of outputting to the control unit 10. That is, the high / low luminance number totaling unit 46 totals the number of pixels in which the luminance signal value of the region does not satisfy the predetermined range, and outputs the total number to the control unit 10.

  The control unit 10 includes a CPU (Central Processing Unit) such as a microcomputer (not shown) and a main memory. The application program stored in the storage unit 13 is developed in the main memory, and the auto iris control unit 11 and the auto focus control unit. 12 is embodied.

  The auto iris control unit 11 acquires the auto iris signal AE from the AE signal generation unit 45, the brightness of the current photographed image recognized by the acquired auto iris signal AE, the opening degree of the aperture 24 of the lens unit 20, the gain of the AGC 33, and the like. A function of generating an auto iris evaluation value, which is an evaluation value for.

The autofocus control unit 12 includes an AF evaluation value generation unit 121, a focus position control unit 122, and an area setting unit 123.
The area setting unit 123 has a function of setting two or more areas in the imaging screen, and outputs information related to the size and setting position of the areas to the signal conversion processing unit 41.

  The AF evaluation value generation unit 121 has a function of setting a threshold value for determining brightness and a threshold value for determining darkness for the high and low luminance number counting units 46a to 46n in advance. The AF evaluation value generation unit 121 has a function of determining whether each region is too bright or too dark based on the luminance number (BN) signal acquired from the high / low luminance count totaling unit 46. The AF evaluation value generation unit 121 satisfies the predetermined range of the luminance signal value of the region based on the luminance number (BN) acquired from the high / low luminance number totaling unit 46 and a threshold value predetermined for the luminance number. And a function for generating an AF evaluation value by adding the VF values of the extracted regions. A detailed method for generating the AF evaluation value will be described later.

  The focus position control unit 122 has a function of controlling the position of the focus lens 25 in the direction in which the AF evaluation value is maximized (the in-focus direction) based on the AF evaluation value. Further, the focus position control unit 122 generates a third motor control signal to control the focusing direction and the focusing position, and outputs the generated third motor control signal to the third driving unit 25d. It has a function. The third drive unit 25d drives and controls the third motor 25m that moves the focus lens group 25 of the lens unit 20 in the optical axis direction based on the third motor control signal. Thereby, AF control is performed.

  The autofocus control unit 12 also includes zoom magnification information representing the current zoom magnification obtained based on the AF evaluation value, lens absolute position information acquired from the absolute position detection unit 21 of the lens unit 20, and the lens unit 20. The first and second motor control signals are generated using the temperature information in the lens unit 20 acquired from the temperature detection unit 22 and the trace curve data stored in the storage unit 13. The autofocus control unit 12 has a function of outputting the generated first motor control signal to the first drive unit 23d and outputting the generated second motor control signal to the second drive unit 24d. Based on the first motor control signal, the first drive unit 23d drives and controls the first motor 23m that moves the variator lens group 23 of the lens unit 20 in the optical axis direction. The second drive unit 24d drives and controls the second motor 24m that drives the diaphragm 24 of the lens unit 20 based on the second motor control signal. Thereby, auto iris control is performed.

  Further, the control unit 10 controls the shutter speed of the electronic shutter 35 so as to increase / decrease the exposure time for the image sensor 31 based on the auto iris evaluation value, and the optical of the subject imaged on the light receiving surface of the image sensor 31. It has a function to adjust the amount of image light. Further, the control unit 10 has a function of performing gain adjustment in the AGC 33 based on the auto iris evaluation value.

Next, a processing flow example of the imaging apparatus 100 will be described with reference to FIGS. 2A and 2B (see FIG. 1 as appropriate).
First, in step S <b> 201, the control unit 10 of the imaging apparatus 100 moves the focus lens 25 in advance to a position that becomes the minimum shooting distance. This is because the focus cannot be achieved when the distance between the imaging device 100 and the subject is shorter than the minimum shooting distance.

  In step S <b> 202, the control unit 10 exposes the image sensor 31 while adjusting the light amount of the optical image of the subject imaged on the light receiving surface of the image sensor 31.

  In step S <b> 203, the region setting unit 123 of the autofocus control unit 12 displays a VF value generation region (region) indicating an area for generating a VF value on the imaging screen via the signal conversion processing unit 41 of the camera signal processing unit 40. Set. Then, the signal conversion processing unit 41 receives information on the size and setting position of the VF value generation region from the region setting unit 123, sets the VF value generation region on the imaging screen, and sets the television of the VF value generation region. Output a signal.

  An example of a state in which the VF value generation area is set is shown in FIG. In FIG. 3, the VF value generation area is represented as a case where the entire area VF10 of the imaging screen and the imaging screen are set to be divided into nine (VF1 to VF9). The VF value generation area is not limited to the position shown in FIG. 3 and may be set at an arbitrary position in the imaging screen.

  Returning to FIG. 2A, in step S204, each of the VF value generation units 42a to 42n acquires a luminance signal of any one VF value generation region. Then, the VF value generation unit 42 generates a VF value (contrast signal value) in the VF value generation region for each position of the focus lens 25.

  In step S205, the AF evaluation value generation unit 121 acquires the VF value of each VF value generation region from each of the VF value generation units 42a to 42n. An example is shown in FIG. In FIG. 4, for each VF value generation region (VF1 to VF10), the horizontal axis represents the focus lens position, and the vertical axis represents the VF value. A VF value curve (real curve) is shown. Note that the VF value of the VF value generation area VF10 (the entire area of the imaging screen) represents the sum of the VF values of the VF value generation area VF1 to VF9.

  Returning to FIG. 2A, in step S206, the AF evaluation value generation unit 121 reads and sets a predetermined threshold value from the storage unit 13. The threshold value is a value used to determine that the brightness number (BN) of each VF value generation area acquired from the high / low brightness count totaling unit 46 exceeds the threshold value and is too bright or too dark. .

In step S207, the AF evaluation value generation unit 121 determines whether the luminance number (BN) of each VF value generation area satisfies a threshold value. Specifically, the AF evaluation value generation unit 121 determines that the threshold value is satisfied when the acquired luminance number (BN) of each VF value generation region is less than the threshold value.
If it is determined that the threshold is satisfied (Yes in step S207), the process proceeds to step S209. If it is determined that the threshold is not satisfied (No in step S207), the process proceeds to step S208.

  For example, in FIG. 4, VF3 and VF9 in the VF value generation area are determined to be “bright” without satisfying the threshold value, and VF7 in the VF value generation area is determined to be “dark” without satisfying the threshold value in the process of step S207. Shows the case.

  Returning to FIG. 2A, in step S208, the AF evaluation value generation unit 121 executes a process of excluding a VF value generation area that does not satisfy the threshold. Specifically, VF3, VF7, and VF9 in the VF value generation area are excluded from the process of generating the AF evaluation value by adding the VF values.

  In step S209, the AF evaluation value generation unit 121 determines whether the slope of the VF value curve is positive. If it is determined that the inclination is positive (Yes in step S209), the process proceeds to step S212. If it is determined that the inclination is not positive (No in step S209), the process proceeds to step S210.

  Here, the meaning of “inclination is positive” will be described with reference to FIG. In FIG. 6, the horizontal axis represents the focus lens position, the vertical axis represents the VF value, and the actual curve in the figure represents the curve of the VF value. The vertical dotted line represents the position of the minimum imaging distance combined in step S201. Therefore, the imaging apparatus 100 cannot focus on the left side of the vertical dotted line because the distance to the subject is too close. In FIG. 6, since the peak of the VF value curve is present on the right side of the vertical dotted line, the imaging apparatus 100 can be focused by aligning the position of the focus lens 25 with the peak. That is, when the inclination when the VF value curve crosses the vertical dotted line is “plus”, that is, “inclination is plus”, the focus lens 25 can be moved to the peak position of the VF value (in-focus). be able to). On the other hand, when the inclination is negative, this means that the imaging apparatus 100 cannot focus.

  Returning to FIG. 2A, in step S210, the AF evaluation value generation unit 121 executes a process of excluding the VF value generation area determined to have a positive slope. Specifically, in FIG. 4, when the VF value generation area is VF1, it is determined that the slope is not positive, that is, “close”. Therefore, VF1 in the VF value generation area is excluded from the process of adding the VF value and generating the AF evaluation value.

As a result of the exclusion process of VF1, VF3, VF7, and VF9 in the VF value generation area, as shown in FIG. 5, the four corners are “masked” in the imaging screen.
By excluding the VF value generation area, the VF value generation unit 42 is vacant (not used), which has the effect of reducing power consumption. On the other hand, in order to utilize the unused VF value generation unit 42, it is possible to provide flexibility such that a new VF value generation area can be set.

  Returning to FIG. 2A, in step S211, the AF evaluation value generation unit 121 generates the sum (AF evaluation value) of the VF values in the VF value generation area that has not been excluded. Specifically, the AF evaluation value generation unit 121 calculates an AF evaluation value by adding the VF values at the same focus lens position in each VF value generation area that is not excluded. For example, in FIG. 4, the VF values of VF2, VF4 to VF6, and VF8 in the VF value generation area are added.

  Returning to FIG. 2A, in step S212, the focus position control unit 122 executes control to move the focus lens 25 in the direction in which the AF evaluation value increases (plus direction). In this control, for example, a hill climbing method or the like can be used. In the case where the AF evaluation value is Yes in step S209, the VF value of VF10 in the VF value generation area acquired in step S205 is used, and in the case of No in step S209, the VF value generated in step S211. The sum of is used.

In step S213, the focus position control unit 122 determines whether the focus lens 25 is at the maximum position of the AF evaluation value.
If it is determined that the AF evaluation value is at the maximum position (Yes in step S213), the process proceeds to an out-of-page connector “A” (step S221 in FIG. 2B) and if it is determined that the AF evaluation value is not at the maximum position (step S221). In step S213, No), the process returns to step S202.

  2B, in step S221, the focus position control unit 122 stops the movement of the focus lens 25. A point where the lens stops means that the focal length is in focus. The processing flow after step S222 is AF control under a state where the focus is once achieved, and is an operation for quickly and accurately following the in-focus position.

  In step S222, when there is an unused VF value generation unit 42, the region setting unit 123 further subdivides the VF value generation region and sets a small region. Note that which VF value generation area is subdivided depends on the VF value generation area located near the center of the imaging screen, the VF value generation area with a large maximum VF value, or the VF value generation area with a large variation in VF value. It is decided to either. In addition, when the position of a person's face or object is detected and focused on the position, the VF value generation area including the focused position may be subdivided. Further, the number of small areas set by subdivision may be all or a part of the number of unused VF value generation units 42.

  FIG. 5 excludes the four VF value generation areas indicated as “mask” in the figure, and subdivides the VF value generation area at the center of the imaging screen into four sub-areas (VF1, VF3, VF5, VF7). Represents a state where is set. This small area has improved sensitivity for detecting the movement of the subject compared to the VF value generation area (VF2, VF4, VF6, VF8).

  Returning to FIG. 2B, in step S <b> 223, the control unit 10 exposes the image sensor 31 while adjusting the light amount of the optical image of the subject imaged on the light receiving surface of the image sensor 31.

  In step S224, the VF value generation unit 42 acquires the luminance signal of the entire region and each small region. The VF value generation unit 42 generates contrast signal values (VF values) for the entire region and each small region. Here, the reason why the VF value of the entire area is obtained is to prevent the excluded VF value generation area from being permanently excluded. Specifically, when there is a large variation in the VF value of the entire area of the captured image, the control unit 10 returns to step S201 in FIG. 2A to detect the focus position again.

  In step S225, the AF evaluation value generation unit 121 acquires the VF values of the entire region and each small region from the VF value generation unit 42. The most recently acquired VF value is referred to as the current VF value.

  In step S226, the AF evaluation value generation unit 121 compares the current and previous AF evaluation values (VF values) of the entire area. Note that the AF evaluation value (VF value) of the entire area is a standard television signal output from the signal conversion processing unit 41 (for example, 60 fields / second for NTSC) or a frame (for example, 30 for NTSC). Generated every frame / second).

  In step S227, the AF evaluation value generation unit 121 determines whether or not there is a change based on the comparison result in step S226. Specifically, the AF evaluation value generation unit 121 determines that the absolute value of the difference between the current AF evaluation value (VF value) of the entire area and the previous AF evaluation value (VF value) of the entire area is a predetermined threshold value (first value). 1 or more), it is determined that there is a fluctuation.

  If it is determined that there is a change (Yes in step S227), the process proceeds to step S235. If it is determined that there is no change (No in step S227), the process proceeds to step S228.

  In step S228, the AF evaluation value generation unit 121 acquires a GYRO sensor value from the GYRO sensor 36.

In step S229, the AF evaluation value generation unit 121 determines whether the position of the imaging device 100 has moved based on the acquired GYRO sensor value.
If it is determined that the position has moved (Yes in step S229), the process proceeds to step S235. If it is determined that the position has not moved (No in step S229), the process proceeds to step S230.

  In step S230, the AF evaluation value generation unit 121 compares the VF values of the current and previous small regions.

In step S231, the AF evaluation value generation unit 121 determines whether or not there is a change based on the comparison result in step S230. Here, the AF evaluation value generation unit 121 determines that there is a change when the absolute value of the difference between the VF value of the current small area and the VF value of the previous small area is greater than or equal to a predetermined threshold (second threshold). judge. The VF value of the small area is a standard television signal output from the signal conversion processing unit 41 (for example, 60 fields / second for NTSC) or a frame (for example, 30 frames / second for NTSC). Is generated.
If it is determined that there is a change (Yes in step S231), the process proceeds to step S232. If it is determined that there is no change (No in step S231), the process returns to step S223.

  In step S232, the AF evaluation value generation unit 121 generates the sum of the VF values of the regions in the direction in which the slope of the VF value curve of the small region is the same.

  In step S233, the focus position control unit 122 moves the focus lens 25 in the direction in which the sum (subtotal value) of the small area VF values calculated in step S232 is large. Specifically, the focus position control unit 122 compares the maximum values of the subtotal values in the different directions, and moves the focus lens 25 in the direction of the larger subtotal value. In this control, for example, a hill climbing method or the like can be used.

  Here, the reason for using the sum of the VF values of the regions in the same direction in which the slopes of the VF values of the small regions calculated in step S232 are subdivided is that the tracking is relaxed without excessively following the movement of the subject. This is to realize the control.

In step S234, the focus position control unit 122 determines whether or not the focus lens 25 is at the maximum position of the sum of the VF values.
If it is determined that the position is at the maximum position of the sum of VF values (Yes in step S234), the process returns to step S221. If it is determined that the position is not the maximum position of the sum of VF values (No in step S234), the process is step S223. Return to.

  In step S235, the settings of the VF value generation area and the small area are canceled. Then, the process returns to the out-of-page connector “B” (step S201 in FIG. 2A).

  As described above, by executing the processing flow described in steps S201 to S213 illustrated in FIG. 2A and steps S221 to S235 illustrated in FIG. 2B, the imaging apparatus 100 can adjust the focal length quickly and with high accuracy. Possible autofocus control can be realized.

  As described above, the imaging apparatus 100 according to the present invention sets two or more areas in the imaging screen and generates a contrast signal value (VF value) for the area. Then, the imaging apparatus 100 adds the contrast signal value of the area in which the luminance signal value of the imaging screen satisfies a predetermined range, and uses the addition result as an AF evaluation value to focus in the direction in which the AF evaluation value is maximized. Control the lens position. Furthermore, the imaging apparatus 100 subdivides the area into two or more small areas, generates a contrast signal value of the small area, and generates a contrast signal value for the entire area of the imaging screen. Next, the imaging apparatus 100 determines that the absolute value of the difference between the current contrast signal value and the previous contrast signal value is less than a predetermined threshold value (first threshold value) for the entire region, and for the small region this time. When the absolute value of the difference between the contrast signal value and the previous contrast signal value is greater than or equal to a predetermined threshold value (second threshold value), the direction in which the contrast signal value of the small region increases in the same direction with respect to the focus lens position A subtotal value is calculated by adding the contrast signal values of the small area, and the focus lens position is controlled in a direction in which the subtotal value increases. Since the imaging apparatus 100 can perform such control, it is possible to realize autofocus control that can adjust the focal length quickly and with high accuracy.

  In the present embodiment, in step S227 of FIG. 2B, the presence / absence of fluctuation is determined using the absolute value of the difference between the current and previous contrast signal values for the entire region. Instead, as a modification, when the correlation coefficient of the current and previous contrast signal values or the similarity of the curve of the contrast signal value with respect to the focus lens position is less than a predetermined threshold (fourth threshold) for the entire area In addition, it may be determined that there is a change. Here, the similarity is a value obtained by quantifying how much they are similar, and the larger the value, the more similar.

  Further, in the present embodiment, in step S231 in FIG. 2B, it is described that the presence / absence of variation is determined using the absolute value of the difference between the current and previous contrast signal values for a small region. Instead, as a modified example, when the correlation coefficient of the current and previous contrast signal values for the small area or the similarity of the contrast signal value curve with respect to the focus lens position is less than a predetermined threshold (third threshold) In addition, it may be determined that there is a change. Here, the similarity is a value obtained by quantifying how much they are similar, and the larger the value, the more similar.

  When a large number of VF value generation units 42 and high / low luminance count totaling units 46 are always used, the amount of power used by the imaging apparatus 100 increases and the temperature inside the imaging apparatus 100 rises. There may be cases that lead to speed. Therefore, the area setting unit 123 may set the number of small areas in consideration of power consumption when setting the small areas by subdividing the areas.

In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another modification, and the configuration of another modification can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
In addition, some or all of the functions and the like of the imaging apparatus 100 may be realized by hardware by designing, for example, an integrated circuit. Further, each function and the like of the control unit 10 may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files for realizing each function is stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD (Digital Versatile Disc). be able to.
In addition, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. In practice, it may be considered that almost all configurations are connected to each other.

DESCRIPTION OF SYMBOLS 10 Control part 11 Auto iris control part 12 Auto focus control part 20 Lens unit 21 Absolute position detection part 22 Temperature detection part 23 Variator lens group (zoom lens)
24 Aperture 25 Focus lens group (focus lens)
31 Image sensor 36 GYRO sensor 40 Camera signal processing part 41 Signal conversion processing part 42 (42a-42n) VF value generation part 43 HPF
44 Integrating Unit 45 AE Signal Generating Unit 46 (46a to 46n) High / Low Luminance Number Counting Unit 121 AF Evaluation Value Generating Unit 122 Focus Position Control Unit 123 Area Setting Unit

Claims (7)

An area setting unit for setting two or more areas in the imaging screen;
A VF value generation unit that generates a contrast signal value of the region for each region;
An AF evaluation value generation unit that adds the contrast signal value of the region for the region where the luminance signal value of the region satisfies a predetermined range, and outputs the addition result as an AF evaluation value;
A focus position control unit that controls a focus lens position in a direction in which the AF evaluation value is maximized,
After the focus lens position where the AF evaluation value is maximized is determined,
The region setting unit subdivides the region into two or more small regions,
The VF value generation unit generates a contrast signal value for the small area, and generates a contrast signal value for the entire area of the imaging screen,
The focus position control unit is configured such that the absolute value of the difference between the current contrast signal value and the previous contrast signal value for the entire region is less than a first threshold, and the current contrast signal value for the small region. If the absolute value of the difference between the previous contrast signal value and the previous contrast signal value is greater than or equal to the second threshold value, the contrast signal value of the small region is the same in the direction in which the contrast signal value of the small region increases relative to the focus lens position. summed to calculate subtotals value, different compared to the direction maximum value of each subtotal value, the larger the subtotal value direction to the focus lens position to that imaging device and controls the. An area setting unit for setting two or more areas in the imaging screen;
A VF value generation unit that generates a contrast signal value of the region for each region;
An AF evaluation value generation unit that adds the contrast signal value of the region for the region where the luminance signal value of the region satisfies a predetermined range, and outputs the addition result as an AF evaluation value;
A focus position control unit that controls a focus lens position in a direction in which the AF evaluation value is maximized,
After the focus lens position where the AF evaluation value is maximized is determined,
The region setting unit subdivides the region into two or more small regions,
The VF value generation unit generates a contrast signal value for the small area, and generates a contrast signal value for the entire area of the imaging screen,
The focus position control unit is configured such that the absolute value of the difference between the current contrast signal value and the previous contrast signal value for the entire region is less than a first threshold, and the current contrast signal value for the small region. Direction in which the contrast signal value of the small region increases with respect to the focus lens position when the correlation coefficient between the previous contrast signal value and the similarity of the curve of the contrast signal value with respect to the focus lens position is less than the third threshold value Calculate the subtotal value by adding the contrast signal values of the subregions that have the same value, compare the maximum value of the subtotal values in different directions, and control the focus lens position in the direction of the larger subtotal value imaging device characterized. An area setting unit for setting two or more areas in the imaging screen;
A VF value generation unit that generates a contrast signal value of the region for each region;
An AF evaluation value generation unit that adds the contrast signal value of the region for the region where the luminance signal value of the region satisfies a predetermined range, and outputs the addition result as an AF evaluation value;
A focus position control unit that controls a focus lens position in a direction in which the AF evaluation value is maximized,
After the focus lens position where the AF evaluation value is maximized is determined,
The region setting unit subdivides the region into two or more small regions,
The VF value generation unit generates a contrast signal value for the small area, and generates a contrast signal value for the entire area of the imaging screen,
The focus position control unit has a correlation coefficient between the current contrast signal value and the previous contrast signal value with respect to the entire region, or the similarity of the curve of the contrast signal value with respect to the focus lens position is a fourth threshold or more, In addition, when the absolute value of the difference between the current contrast signal value and the previous contrast signal value for the small area is equal to or greater than the second threshold, the direction in which the contrast signal value of the small area increases with respect to the focus lens position. Calculate the subtotal value by adding the contrast signal values of the subregions that are the same, compare the maximum value of the subtotal values in different directions, and control the focus lens position in the direction of the larger subtotal value It characterized imaging device. An area setting unit for setting two or more areas in the imaging screen;
A VF value generation unit that generates a contrast signal value of the region for each region;
An AF evaluation value generation unit that adds the contrast signal value of the region for the region where the luminance signal value of the region satisfies a predetermined range, and outputs the addition result as an AF evaluation value;
A focus position control unit that controls a focus lens position in a direction in which the AF evaluation value is maximized,
After the focus lens position where the AF evaluation value is maximized is determined,
The region setting unit subdivides the region into two or more small regions,
The VF value generation unit generates a contrast signal value for the small area, and generates a contrast signal value for the entire area of the imaging screen,
The focus position control unit has a correlation coefficient between the current contrast signal value and the previous contrast signal value with respect to the entire region, or the similarity of the curve of the contrast signal value with respect to the focus lens position is a fourth threshold or more, If the correlation coefficient between the current contrast signal value and the previous contrast signal value for the small region or the similarity of the curve of the contrast signal value with respect to the focus lens position is less than the third threshold, The subtraction value is calculated by adding the contrast signal values of the subregions where the contrast signal values of the subregions increase in the same direction, and the maximum value of the subtotal values in the different directions is compared. IMAGING dEVICE you and controls the focus lens position in the direction of the subtotal values. The focus position control unit newly sets the area when the absolute value of the difference between the current contrast signal value and the previous contrast signal value is greater than or equal to the first threshold with respect to the entire area. The imaging device according to claim 1 or 2 . The focus position control unit has a correlation coefficient between the current contrast signal value and the previous contrast signal value with respect to the entire area or a similarity of a curve of the contrast signal value with respect to the focus lens position is less than the fourth threshold value. case, the imaging apparatus according to claim 3 or claim 4, characterized in that newly set the region. An autofocus control method for an imaging apparatus,
The imaging device
An area setting step for setting two or more areas in the imaging screen;
A VF value generating step for generating a contrast signal value of the region;
An AF evaluation value generating step of adding the contrast signal value of the region in which the luminance signal value of the region satisfies a predetermined range, and outputting the addition result as an AF evaluation value;
Upon executing a focus position control step of the AF evaluation value to control the focus lens position in the direction of maximum,
The imaging device
After the focus lens position where the AF evaluation value is maximized is determined,
In the region setting step, the region is subdivided into two or more small regions,
In the VF value generation step, the contrast signal value of the small area is generated, and the contrast signal value is generated for the entire area of the imaging screen,
In the focus position control step, the absolute value of the difference between the current contrast signal value and the previous contrast signal value for the entire area is less than a first threshold value, and the current contrast signal value for the small area If the absolute value of the difference between the previous contrast signal value and the previous contrast signal value is greater than or equal to the second threshold value, the contrast signal value of the small region is the same in the direction in which the contrast signal value of the small region increases with respect to the focus lens position. An autofocus control method comprising: calculating a subtotal value by addition, comparing maximum values of subtotal values in different directions, and controlling a focus lens position in a direction of a larger subtotal value .

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