Patent ID: 12253742

EXPLANATION OF REFERENCES

40: lens device1: imaging lens8: lens driving section2: stop9: stop driving section4: lens control unit5: imaging elementX: row directionY: column direction53: AF area50: light-receiving surface51: pixel52A,52B: phase difference detection pixelPL1, PL2, PL3: pair linec: opening6: analog signal processing section7: analog digital conversion circuit10: imaging element driving section11: system control unit11A: addition correlation operation unit11B: non-addition correlation operation unit11C: selection unit11D: defocus amount calculation unit11E: lens driving section11F: reliability determination unit14: operation unit15: memory control unit16: main memory17: digital signal processing section20: external memory control unit21: recording medium22: display control unit23: display unit24: control bus25: data busCS1, CS2, C1, C2, C3, C4: correlation curve80: range100: lens device111: focus lens112,113: zoom lens114: stop115: master lens group116: beam splitter116a: reflecting surface117: mirror118: condenser lens119: separator lens19R,19L: lens120: imaging element121: AF unit300: camera device310: imaging element320: image processing section200: smart phone201: housing202: display panel203: operation panel204: display input unit205: speaker206: microphone207: operation unit208: camera unit210: wireless communication unit211: communication unit212: storage unit213: external input/output unit214: GPS receiving unit215: motion sensor unit216: power source unit217: internal storage section218: external storage section220: main control unitST1to STn: GPS satellite

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings.

FIG.1is a diagram showing a schematic configuration of a digital camera that is an example of an imaging device according to an embodiment of the invention.

The digital camera shown inFIG.1includes a lens device40that includes an imaging lens1, a stop2, a lens control unit4, a lens driving section8, and a stop driving section9. In this embodiment, the lens device40may be detachably provided with respect to a digital camera main body, or may be fixed to the digital camera main body.

The imaging lens1and the stop2form an imaging optical system, and the imaging optical system at least includes a focus lens. The focus lens is a lens for adjusting a focusing position of the imaging optical system, and is configured of a single lens or plural lenses. As the focus lens is moved in an optical axis direction of the imaging optical system, the focusing position is adjusted.

The lens control unit4of the lens device40is configured to be communicable with a system control unit11of the digital camera main body in a wired or wireless manner. The lens control unit4drives the focus lens included in the imaging lens1through the lens driving section8, or drives the stop2through the stop driving section9, in accordance with a command from the system control unit11.

The digital camera main body includes an imaging element5such as a CCD image sensor or a CMOS image sensor that images a subject through the imaging optical system, an analog signal processing section6that is connected to an output end of the imaging element5and performs analog signal processing such as correlative double sampling processing, and an analog digital conversion circuit7that converts an analog signal output from the analog signal processing section6into a digital signal, the system control unit11, and an operation unit14. The analog signal processing section6and the analog digital conversion circuit7are controlled by the system control unit11.

The system control unit11that generally controls the entirety of an electric control system of the digital camera drives the imaging element5through the imaging element driving section10, and outputs a subject image obtained through the lens device40as a captured image signal. A command signal from a user is input to the system control unit11through the operation unit14.

The system control unit11is configured of a processor and a memory such as a random access memory (RAM) and a read only memory (ROM). The system control unit11executes programs including a focusing control program stored in the ROM that is provided therein, to thereby realize respective functions to be described later. The system control unit11forms a focusing control device.

Further, an electric control system of the digital camera includes a main memory16, a memory control unit15connected to the main memory16, a digital signal processing section17that performs signal processing with respect to a captured image signal output from the analog digital conversion circuit7to generate captured image data, an external memory control unit20to which an attachable and detachable recording medium21is connected, and a display control unit22to which a display unit23mounted on a rear surface or the like of the camera is connected.

The memory control unit15, the digital signal processing section17, the external memory control unit20, and the display control unit22are connected to each other through a control bus24and a data bus25, and are controlled by commands from the system control unit11.

FIG.2is a schematic plan view illustrating a configuration of the imaging element5mounted on the digital camera shown inFIG.1.

The imaging element5includes a light-receiving surface50on which multiple pixels are arranged in a two-dimensional pattern in a row direction X that is one direction and a column direction Y that is a direction orthogonal to the row direction X. On the light-receiving surface50, nine focus detection areas (hereinafter, referred to as an AF area)53that are target areas to be focused are provided in the example ofFIG.2. In the digital camera shown inFIG.1, one or more areas are selected from the nine AF areas53shown inFIG.2, and then, the phase difference of the subject imaged in the selected AF area53is calculated.

The AF area53is an area that includes an imaging pixel and a phase difference detection pixel as pixels.

On the light-receiving surface50, in a portion where the AF areas53are excluded, only imaging pixels are disposed. The AF areas53may be provided on the light-receiving surface50without a gap.

FIG.3is a partially enlarged view showing a single AF area53shown inFIG.2.

Pixels51(square shaped blocks in the figure) are arranged in the AF area53in a two-dimensional pattern. Each pixel51includes a photoelectric conversion unit such as a photo diode, and a color filter formed above the photoelectric conversion unit.

InFIG.3, letter “R” is given to a pixel51(R pixel51) including a color filter (R filter) that transmits red light.

Letter “G” is given to a pixel51(G pixel51) including a color filter (G filter) that transmits green light.

Letter “B” is given to a pixel51(B pixel51) including a color filter (B filter) that transmits blue light. The color filters are arranged in the form of a Bayer array over the entirety of the light-receiving surface50.

In the AF area53, a part of the G pixels51(shaded pixels inFIG.3) are used as the phase difference detection pixels52A and52B. In the example ofFIG.3, each G pixel51in a certain pixel row among pixel rows including the R pixels51and the G pixels51is used as the phase difference detection pixel52A. Further, the G pixel51of the same color closest to each G pixel51in the column direction Y is used as the phase difference detection pixel52B.

The phase difference detection pixel52A and the phase difference detection pixel52B of the same color closest to the phase difference detection pixel52A in the column direction Y form a pair.

A pair line PL1is formed by plural pairs that are arranged in the row direction X by the phase difference detection pixels52A disposed in the third pixel row from the top ofFIG.3and the phase difference detection pixels52B disposed in the fifth pixel row from the top ofFIG.3.

A pair line PL2is formed by plural pairs that are arranged in the row direction X by the phase difference detection pixels52A disposed in the seventh pixel row from the top ofFIG.3and the phase difference detection pixels52B disposed in the ninth pixel row from the top ofFIG.3.

A pair line PL3is formed by plural pairs that are arranged in the row direction X by the phase difference detection pixels52A disposed in the eleventh pixel row from the top ofFIG.3and the phase difference detection pixels52B disposed in the thirteenth pixel row from the top ofFIG.3.

In this way, in the AF area53, plural pair lines are arranged in the column direction Y.

FIG.4is a diagram showing phase difference detection pixels that form a certain pair line shown inFIG.3.

The phase difference detection pixel52A is a first signal detection unit that receives a beam that passes through one divided region in a pupil region of the imaging lens1, divided in the row direction X, and detects a signal depending on the intensity of received light.

The phase difference detection pixel52B is a second signal detection unit that receives a beam that passes through the other divided region in the pupil region of the imaging lens1and detects a signal depending on the intensity of received light.

In the AF area53, plural pixels51other than the phase difference detection pixels52A and52B are imaging pixels. Each imaging pixel receives beams that pass through the two divided regions in the pupil region of the imaging lens1, and detects a signal depending on the intensity of received light.

A light shielding film is provided above the photoelectric conversion unit of each pixel51, and an opening for defining a light-receiving area of the photoelectric conversion unit is formed in the light shielding film.

The center of the opening of the imaging pixel51matches the center of the photoelectric conversion unit of the imaging pixel51. On the other hand, the center of the opening (white portion inFIG.4) of the phase difference detection pixel52A is eccentric rightward with respect to the center of the photoelectric conversion unit of the phase difference detection pixel52A.

Further, the center of the opening (white portion inFIG.4) of the phase difference detection pixel52B is eccentric leftward with respect to the center of the photoelectric conversion unit of the phase difference detection pixel52B. Here, the right direction represents one direction along the row direction X shown inFIG.3, and the left direction represents the other direction along the row direction X.

FIG.5is a diagram showing a configuration of cross-sections of the phase difference detection pixels52A. As shown inFIG.5, an opening c of the phase difference detection pixel52A is eccentric rightward with respect to the photoelectric conversion unit (PD).

As shown inFIG.5, by covering one side of the photoelectric conversion unit by the light shielding film, it is possible to selectively shield light incident in a direction opposite to a side where the photoelectric conversion unit is covered by the light shielding film.

With such a configuration, it is possible to detect, using a pixel group that includes the phase difference detection pixels52A that form a pair line and a pixel group that includes the phase difference detection pixels52B that form the pair line, a phase difference in the row direction X in images respectively captured by the two pixel groups.

The pixel configuration of the imaging element5is not limited to the configuration shown inFIGS.2to5.

For example, a configuration in which all pixels included in the imaging element5are used as imaging pixels51and each imaging pixel51is divided into two parts, in which one divided part is used as a phase difference detection pixel52A and the other divided part is used as a phase difference detection pixel52B, may be used.

FIG.6is a diagram illustrating a configuration in which all pixels included in the imaging element5are used as imaging pixels51and each imaging pixel51is divided into two parts.

In the configuration ofFIG.6, each imaging pixel51with R in the imaging element5is divided into two parts, and the divided two parts are used as a phase difference detection pixel r1and a phase difference detection pixel r2, respectively.

Further, each imaging pixel51with G in the imaging element5is divided into two parts, and the divided two parts are used as a phase difference detection pixel g1and a phase difference detection pixel g2, respectively.

Furthermore, each imaging pixel51with B in the imaging element5is divided into two parts, and the divided two parts are used to as a phase difference detection pixel b1and a phase difference detection pixel b2, respectively.

In this configuration, the phase difference detection pixels r1, g1, and b1serve as the first signal detection units, respectively, and the phase difference detection pixels r2, g2, and b2serve as the second signal detection units, respectively. Further, two phase difference detection pixels included in one imaging pixel51form a pair.

In the configuration example ofFIG.6, in a case where signals of the first signal detection unit and the second signal detection unit included in one imaging pixel51are added up, a normal imaging signal having no phase difference is obtained. That is, in the configuration ofFIG.6, it is possible to use all pixels as both of phase difference detection pixels and imaging pixels.

In this way, the imaging element5forms a sensor that has plural pair lines that are arranged in the column direction Y, in which each pair line is formed by plural pairs that are arranged in the row direction X and each pair includes the first signal detection unit and the second signal detection unit.

FIG.7is a functional block diagram of the system control unit11shown inFIG.1. The system control unit11executes the focusing control program stored in the ROM that is provided therein, to thereby function as an addition correlation operation unit11A, a non-addition correlation operation unit11B, a selection unit11C, a defocus amount calculation unit11D, a lens driving section11E.

The addition correlation operation unit11A performs a correlation operation between a first signal group obtained by adding up detection signals detected by the same phase difference detection pixels52A of which positions in the row direction X are the same, included in all pair lines (hereinafter, referred to as N pair lines) disposed in a selected AF area53and a second signal group obtained by adding up detection signals detected by the same phase difference detection pixels52B of which positions in the row direction X are the same, included in the N pair lines.

The addition correlation operation unit11A calculates addition values of the detection signals detected by the same phase difference detection pixels52A of which the positions in the row direction X are the same, included in the N pair lines or average values of the detection signals detected by the same phase difference detection pixels52A of which the positions in the row direction X are the same, included in the N pair lines as the first signal group.

The addition correlation operation unit11A calculates addition values of the detection signals detected by the same phase difference detection pixels52B of which the positions in the row direction X are the same, included in the N pair lines or average values of the detection signals detected by the same phase difference detection pixels52B of which the positions in the row direction X are the same, included in the N pair lines as the second signal group.

The addition correlation operation unit11A performs an operation of the following expression (1) by setting the first signal group as A1(1), A1(2), . . . , and A1(k), setting the second signal group as B1(1), B1(2), . . . , and B1(k), and setting a certain shift amount in a case where the two signal groups shift in the row direction X as d (L is an arbitrary value), to thereby calculate a correlation value S1(d) between the first signal group and the second signal group.

[Expression⁢⁢1]S1⁡(d)=∑x=1k⁢A1⁡(x)-B1⁡(x-d)(1)d=-L,…⁢,-2-1,0,1,2,…⁢⁢L

The non-addition correlation operation unit11B performs, for each of N pair lines disposed in a selected AF area53, a correlation operation between a third signal group that is a detection signal group formed by detection signals detected by the phase difference detection pixels52A included in the pair line and a fourth signal group that is a detection signal group formed by detection signals detected by the phase difference detection pixels52B included in the pair line.

The non-addition correlation operation unit11B performs an operation of the following expression (2) by setting the third signal group as A2(1), A2(2), . . . , and A2(k) and setting the fourth signal group as B2(1), B2(2), . . . , and B2(k), to thereby calculate a correlation value S3(d) between the third signal group and the fourth signal group. The non-addition correlation operation unit11B performs the operation of the following Expression (2) with respect to N pair lines, to thereby calculate N correlation values S3(d).

[Expression⁢⁢2]S3⁡(d)=∑x=1k⁢A2⁡(x)-B2⁡(x-d)(2)

The non-addition correlation operation unit11B calculates correlation values S2(d) on the basis of the N correlation value S3(d).

In a case where the first signal group and the second signal group are respectively calculated as addition values, the non-addition correlation operation unit11B adds up correlation values corresponding to values having the same shift amounts in the N correlation value S3(d), and calculates the correlation value S2(d) indicating a relationship between the shift amount d and an addition value of the N correlation values.

Alternatively, in a case where the first signal group and the second signal group are respectively calculated as average values, the non-addition correlation operation unit11B calculates average values of correlation values corresponding to values having the same shift amounts in the N correlation value S3(d), and calculates the correlation value S2(d) indicating a relationship between the shift amount d and an average value of the N correlation values.

The correlation value S1(d) calculated by the addition correlation operation unit11A forms first result information that is information indicating a result of the correlation operation of the addition correlation operation unit11A.

The correlation value S2(d) calculated by the non-addition correlation operation unit11B forms second result information that is information indicating a result of the correlation operation based on the non-addition correlation operation unit11B.

The selection unit11C calculates a matching rate between the correlation value S1(d) calculated by the addition correlation operation unit11A and the correlation value S2(d) calculated by the non-addition correlation operation unit11B, and selects any one of the correlation value S1(d) or the correlation value S2(d) on the basis of the calculated matching rate.

FIGS.8and9are diagrams showing examples of a graph (correlation curve CS1) indicated by the correlation value S1(d) and a graph (correlation curve CS2) indicated by the correlation value S2(d). InFIGS.8and9, a lateral axis represents a shift amount d, and a longitudinal axis represents a correlation value.

The selection unit11C calculates an index indicating a similarity of shapes of the correlation curve CS1and the correlation curve CS2shown inFIGS.8and9as a matching rate.

For example, the selection unit11C calculates a matching rate C between the correlation value S1(d) and the correlation value S2(d) by performing an operation of the following Expression (3) or (4).

A range in which a sum is taken in Expression (3) or (4) may be a range of a predetermined shift amount centering around a minimum value d=dminof a correlation curve indicated by the correlation value S1(d), but the entire range of the shift amount d may be used as the range in which the sum is taken. By limiting the range in which the sum is taken, it is possible to simplify the operation process.

[Expression⁢⁢3]C=∑S1⁡(d)∑S2⁡(d)(3)[Expression⁢⁢4]C=1∑(S1⁡(d)-S2⁡(d))(4)

The matching rate C calculated by the operation of Expression (3) shows a rate between an area surrounded by the correlation curve CS1and the lateral axis and an area surrounded by the correlation curve CS2and the lateral axis, in a range80of the shift amount d centering around the minimum value dminof the correlation curve CS1, in the example shown inFIG.8. As shown inFIG.9, as the similarity of the shapes of the correlation curve CS1and the correlation curve CS2becomes higher, the matching rate C calculated by Expression (3) has a larger value.

The matching rate C calculated by the operation of Expression (4) represents a reciprocal of a value obtained by integrating and accumulating differences between respective correlation values of the correlation curve CS1and respective correlation values of the correlation curve CS2in the range80, in the example shown inFIG.8. As shown inFIG.9, as the similarity of the shapes of the correlation curve CS1and the correlation curve CS2becomes higher, the matching rate C calculated by Expression (4) has a larger value.

In a case where the matching rate C exceeds a predetermined matching threshold value (for example, in the case of the result as shown inFIG.9), the selection unit11C selects the correlation value S1(d). In a case where the matching rate C is equal to or smaller than the matching threshold value (for example, in the case of the result as shown inFIG.8), the selection unit11C selects the correlation value S2(d).

The defocus amount calculation unit11D calculates a shift amount when a correlation value becomes a minimum value as a phase difference value, on the basis of the correlation value S1(d) and the correlation value S2(d). The defocus amount calculation unit11D converts the calculated phase difference into a defocus amount, and decides a target position of the focus lens on the basis of the defocus amount.

The lens driving section11E controls the lens control unit4to move the focus lens to the target position decided by the defocus amount calculation unit11D.

FIG.10is a flowchart for describing a focusing control operation of the digital camera shown inFIG.1.

In a case where the operation unit14is operated in a state where a certain area is selected from nine AF areas53by a user of the digital camera and a command for performing AF is input (YES in step S1), the system control unit11causes the imaging element5to perform imaging for AF. The system control unit11acquires captured image signals output from the selected AF area53of the imaging element5due to the imaging (step S2).

The addition correlation operation unit11A calculates average values of detection signals detected by the phase difference detection pixels52A of which the positions in the row direction X are the same, included in all pair lines included in the selected AF area53, and calculates average values of detection signals detected by the phase difference detection pixels52B of which the positions in the row direction X are the same, included in all the pair lines, among the captured image signals acquired in step S2. Further, the addition correlation operation unit11A performs a correlation operation between the calculated average values to calculate the correlation values S1(d) (step S3).

The non-addition correlation operation unit11B performs, for each of the pair lines included in the selected AF area53, a correlation operation between a detection signal group detected by the phase difference detection pixels52A included in the pair line and a detection signal group detected by the phase difference detection pixels52B included in the pair line, among the captured image signals acquired in step S2, to calculate the correlation values S2(d) on the basis of the result of the correlation operation (step S4).

Then, the selection unit11C calculates a matching rate C between the correlation value S1(d) calculated in step S3and the correlation value S2(d) calculated in step S4, and determines whether the calculated matching rate C exceeds a matching threshold value (step S5).

In a case where it is determined that the matching rate C exceeds the matching threshold value (YES in step S5), the selection unit11C selects the correlation value S1(d). Further, the defocus amount calculation unit11D calculates a shift amount d in which the correlation value S1(d) selected by the selection unit11C becomes a minimum value as a phase difference value (step S6).

On the other hand, in a case where it is determined that the matching rate C is equal to or smaller than the matching threshold value (NO in step S5), the selection unit11C selects the correlation value S2(d). Further, the defocus amount calculation unit11D calculates a shift amount d in which the correlation value S2(d) selected by the selection unit11C becomes a minimum value as a phase difference value (step S7).

After step S6and step S7, the defocus amount calculation unit11D converts the calculated phase difference into a defocus amount, and decides a target position of the focus lens on the basis of the defocus amount (step S8).

After step S8, the lens driving section11E controls the focus lens to move the target position decided by the defocus amount calculation unit11D (step S9), and then, AF is terminated.

As described above, the digital camera shown inFIG.1selects the correlation value S1(d) or the correlation value S2(d) on the basis of the matching rate C between the correlation value S1(d) and the correlation value S2(d), and drives the focus lens on the basis of the selected correlation value.

In a case where the matching rate C is high, by driving the focus lens on the basis of the correlation value S1(d) that is a result of a correlation operation that is not easily affected by noise, it is possible to perform AF with high accuracy.

On the other hand, in a case where the matching rate C is low, results of correlation operations are different from each other between a case where detection signals of phase difference detection pixels are added up and a case where detection signals of phase difference detection pixels are not added up, and it may be determined that this situation is a situation that contrast is lowered due to the addition.

Accordingly, in such a case, by driving the focus lens on the basis of the correlation value S2(d) that is a result of the correlation operation with a low possibility that contrast is lowered, it is possible to perform AF with high accuracy.

It is preferable that the selection unit11C variably controls the matching threshold value.

For example, as the brightness of a subject imaged in the selected AF area53is darker (the brightness is lower), the selection unit11C sets the matching threshold value to be smaller.

Alternatively, as an imaging sensitivity (ISO sensitivity) of the digital camera is higher, the selection unit11C sets the matching threshold value to be smaller. The ISO sensitivity is a standard defined by the International Standard Organization.

In a situation where the brightness of a subject is dark or in a situation where the imaging sensitivity is set to be high, noise components included in a captured image signal become large.

Accordingly, in such a situation, by increasing a probability that the correlation value S1(d) that is not easily affected by noise may be selected by setting the matching threshold value to be small, it is possible to enhance the AF accuracy.

Hereinafter, a modification example of the digital camera shown inFIG.1will be described.

First Modification Example

FIG.11is a diagram illustrating a modification example of functional blocks of the system control unit11shown inFIG.7. The system control unit11shown inFIG.11has the same configuration as inFIG.7except that a reliability determination unit11F is additionally provided.

The reliability determination unit11F determines a reliability of the correlation value S1(d) calculated by the addition correlation operation unit11A. Hereinafter, a reliability determination method of the correlation value S1(d) will be described.

FIG.12AandFIG.12Bare diagrams respectively showing an example of a graph (correlation curve CS1) indicated by the correlation value S1(d).

In the correlation curve CS1, it can be determined that as a shape close to a minimum value of the correlation value becomes flat, a detection signal group used for a correlation operation shows a low contrast. For example, in the example shown inFIG.12A, a correlation curve C1has a higher reliability compared with a reliability of a correlation curve C2.

Then, the reliability determination unit11F calculates a flatness of the shape close to the minimum value of the correlation curve, and determines the reliability of the correlation value S1(d) on the basis of the calculated flatness.

Specifically, the reliability determination unit11F calculates a coefficient a of a quadratic function v shown in Expression (5), using plural correlation values close to the minimum value of the correlation curve CS1and shift amounts corresponding to the correlation values, and handles the coefficient a as a numerical value indicating the reliability of the correlation value S1(d). As the coefficient a becomes larger, the reliability of the correlation value S1(d) becomes higher.
v=a·s2+b·s+s+c(5)
where v is a correlation value, s is a shift amount, and a, b, and c are coefficients.

Further, in the correlation curve CS1, it can be determined that as the minimum value becomes smaller, a correlation between two signal groups that are targets for a correlation operation becomes larger. For example, in the example shown inFIG.12B, a reliability of a correlation curve C4has a higher reliability compared with a reliability of a correlation curve C3.

Accordingly, the reliability determination unit11F handles a reciprocal of the size of the minimum value of the correlation curve CS1as a numerical value indicating the reliability of the correlation value S1(d). As the minimum value of the correlation curve CS1becomes smaller, the reliability of the correlation value S1(d) becomes higher.

Even in a case where a subject image captured in the AF area53has a low contrast, there is a case where the minimum value of the correlation curve CS1becomes small.

Thus, it is preferable that the reliability determination unit11F first calculates the coefficient a of the quadratic function v in Expression (5) and determines the reliability based on the size of the minimum value only in a case where the coefficient a is sufficiently large.

In the first modification example, as a result of the determination in the reliability determination unit11F, in a case where the reliability of the correlation value S1(d) exceeds a predetermined reliability threshold value, the selection unit11C selects the correlation value S1(d).

As the result of the determination in the reliability determination unit11F, in a case where the reliability of the correlation value S1(d) is equal to or smaller than the reliability threshold value, the selection unit11C selects any one of the correlation value S1(d) or the correlation value S2(d) on the basis of the above-mentioned matching rate C.

FIG.13is a flowchart for describing the first modification example of the focusing control operation of the digital camera shown inFIG.1. InFIG.13, the same reference numerals are given to the same processes as inFIG.10, and description thereof will not be repeated.

After the correlation value S1(d) is calculated in step S3, the reliability determination unit11F determines the reliability of the correlation value S1(d), on the basis of the shape close to the minimum value of the correlation curve indicated by the correlation value S1(d), the size of the minimum value, or the like (step S21).

In a case where the reliability of the correlation value S1(d) determined in step S21exceeds a reliability threshold value (YES in step S22), the correlation value S1(d) is selected by the selection unit11C. Then, the defocus amount calculation unit11D calculates a shift amount when the selected correlation value S1(d) becomes a minimum value as a phase difference (step S23).

On the other hand, in a case where the reliability of the correlation value S1(d) determined in step S21is equal to or smaller than the reliability threshold value (NO in step S22), the non-addition correlation operation unit11B calculates the correlation value S2(d) on the basis of the captured image signal acquired in step S2(step S24).

After step S24, the selection unit11C calculates a matching rate C between the correlation value S1(d) calculated in step S3and the correlation value S2(d) calculated in step S24, and determines whether the calculated matching rate C exceeds a matching threshold value (step S25).

In a case where it is determined that the matching rate C exceeds the matching threshold value (YES in step S25), the selection unit11C selects the correlation value S1(d), and then, the process of step S23is performed.

In a case where it is determined that the matching rate C is equal to or smaller than the matching threshold value (NO in step S25), the selection unit11C selects the correlation value S2(d). Further, the defocus amount calculation unit11D calculates a shift amount in which the selected correlation value S2(d) becomes a minimum value as a phase difference value (step S26).

After step S23and step S26, the process of step S8and subsequent processes are performed.

As described above, according to the first modification example, in a case where the reliability of the correlation value S1(d) is high, the focus lens is driven on the basis of the correlation value S1(d), without performing a correlation operation necessary for calculation of the correlation value S2(d). Accordingly, according to imaging situations, it is possible to reduce the amount and time of the operation necessary for operation of the correlation value S2(d), to thereby reduce an AF time and power consumption.

On the other hand, in a case where the reliability of the correlation value S1(d) is low, any one of the correlation value S1(d) or the correlation value S2(d) is selected on the basis of the matching rate C, and then, the focus lens is driven on the basis of the selected correlation value. Thus, as described above, it is possible to select an optimal correlation value according to subjects, and to enhance the accuracy of AF.

Second Modification Example

A configuration of functional blocks of the system control unit11in a second modification example is the same as that shown inFIG.7.

In the second modification example, the selection unit11C selects the correlation value S1(d) in a case where the defocus amount based on the correlation value S1(d) calculated by the addition correlation operation unit11A exceeds a predetermined defocus threshold value.

The selection unit11C selects any one of the correlation value S1(d) or the correlation value S2(d) on the basis of the matching rate C between the correlation value S1(d) and the correlation value S2(d) in a case where the defocus amount is equal to or smaller than the defocus threshold value.

FIG.14is a flowchart for describing the second modification example of the focusing control operation of the digital camera shown inFIG.1. InFIG.14, the same reference numerals are given to the same processes as inFIG.10, and description thereof will not be repeated.

After the correlation value S1(d) is calculated in step S3, the defocus amount calculation unit11D calculates a shift amount in which the correlation value S1(d) becomes a minimum value as a first phase difference (step S31), and then, calculates a first defocus amount from the calculated first phase difference (step S32).

The selection unit11C determines whether the first defocus amount calculated in step S32exceeds a defocus threshold value THd (step S33).

In a case where the first defocus amount exceeds the defocus threshold value THd (YES in step S33), the selection unit11C selects the correlation value S1(d). Subsequently, the defocus amount calculation unit11D decides a target position of the focus lens on the basis of the first defocus amount calculated on the basis of the correlation value S1(d). Then, the lens driving section11E drives the focus lens to the target position (step S34).

The defocus threshold value THd is set to a value calculated by the following Expression (6) when an F-Number of the stop2is represented as f, an allowable confusion circle is represented as σ [um], and K represents an arbitrary coefficient. Here, ε represents a focal depth.
THd=K×ε
ε=f×σ(6)

In a case where the first defocus amount is equal to or smaller than the defocus threshold value THd (NO in step S33), the non-addition correlation operation unit11B calculates the correlation value S2(d) on the basis of the captured image signal acquired in step S2(step S35).

After step S35, the selection unit11C calculates a matching rate C between the correlation value S1(d) calculated in step S3and the correlation value S2(d) calculated in step S35, and determines whether the calculated matching rate C exceeds a matching threshold value (step S36).

In a case where it is determined that the matching rate C exceeds the matching threshold value (YES in step S36), the selection unit11C selects the correlation value S1(d), and then, the process of step S34is performed.

In a case where it is determined that the matching rate C is equal to or smaller than the matching threshold value (NO in step S36), the selection unit11C selects the correlation value S2(d). Further, the defocus amount calculation unit11D calculates a shift amount in which the selected correlation value S2(d) becomes a minimum value as a second phase difference value (step S37).

Subsequently, the defocus amount calculation unit11D calculates a second defocus amount from the calculated second phase difference (step S38), and decides a target position of the focus lens on the basis of the second defocus amount. Then, the lens driving section11E drives the focus lens to the target position (step S39).

As described above, according to the second modification example, in a case where the defocus amount based on the correlation value S1(d) is large, that is, in a state where blurriness of a captured image is large, the calculation of the correlation value S2(d) is not performed, and the focus lens is driven on the basis of the correlation value S1(d).

In the state where the blurriness is large, there is a low possibility that the contrast is lowered as detection signals of phase difference detection pixels in plural pair lines are added up. Accordingly, in such a case, by driving the focus lens on the basis of the correlation value S1(d) capable of reducing the influence of noise, it is possible to enhance the accuracy of AF.

Further, since a correlation operation for calculating the correlation value S2(d) is not performed, it is possible to reduce the amount of the operation and the operation time, to thereby reduce the AF time and power consumption.

On the other hand, in a case where the defocus amount based on the correlation value S1(d) is small, any one of the correlation value S1(d) or the correlation value S2(d) is selected on the basis of the matching rate C, and then, the focus lens is driven on the basis of the selected correlation value. Thus, as described above, it is possible to select an optimal correlation value according to subjects, to thereby enhance the AF accuracy.

In the above-described digital camera, the imaging element5for imaging a subject is also used as an AF sensor, but a configuration in which an exclusive sensor other than the imaging element5is provided in the digital camera may be used.

For example, a configuration in which a sensor exclusive for phase difference detection (a sensor in which the phase difference detection pixels as shown inFIG.4are only disposed) is provided in the lens device40, light of an imaging optical system is imported using the sensor, and a correlation operation is performed using an output of the sensor may be used.

In the case of this configuration, a configuration in which the lens control unit4of the lens device40has respective functional blocks of the system control unit11may be used.

In the above description, the digital camera is shown as an example, but for example, the invention may be applied to a broadcasting imaging system.

FIG.15is a diagram showing a schematic configuration of an imaging system that is an example of the imaging device according to the embodiment of the invention. The imaging system is a work system for broadcasting, movies, or the like.

The imaging system shown inFIG.15includes a lens device100, and a camera device300on which the lens device100is mounted.

The lens device100includes a focus lens111, zoom lenses112and113, a stop114, and a master lens group115, which are sequentially arranged from a subject side.

The focus lens111, the zoom lenses112and113, the stop114, and the master lens group115form an imaging optical system. The imaging optical system includes at least the focus lens111.

The lens device100further includes a beam splitter116including a reflecting surface116a, a mirror117, a condenser lens118, a separator lens119, and an AF unit121including an imaging element120. The imaging element120is an image sensor such as a CCD type image sensor or a CMOS type image sensor having plural pixels that are two-dimensionally arranged.

The beam splitter116is disposed between the stop114and the master lens group115on an optical axis K.

The beam splitter116transmits a part (for example, 80% of subject light) of the subject light that is incident onto the imaging optical system and passes through the stop114, and reflects the remaining part (for example, 20% of the subject light) of the subject light from the reflecting surface116ain a direction orthogonal to the optical axis K.

The position of the beam splitter116is not limited to the position shown inFIG.15, and may be disposed at a position behind a lens of the imaging optical system disposed to be closest to a subject on the optical axis K.

The mirror117is disposed on an optical path of light reflected from the reflecting surface116aof the beam splitter116, and reflects the light to be incident onto the condenser lens118of the AF unit121.

The condenser lens118collects light reflected from the mirror117.

The separator lens119includes two lenses19R and19L that are disposed side by side in one direction (a horizontal direction in the example ofFIG.15) with the optical axis of the imaging optical system being interposed therebetween, as shown in an enlarged front view indicated by a broken line inFIG.15.

The subject light condensed by the condenser lens118passes each of the two lenses19R and19L, and is imaged at different positions on a light-receiving surface (surface on which plural pixels are disposed) of the imaging element120. That is, a pair of subject light images that shifts from each other in the one direction is imaged on the light-receiving surface of the imaging element120.

The beam splitter116, the mirror117, the condenser lens118, and the separator lens119function as an optical element that causes a part of subject light that is incident onto the imaging optical system to be incident onto an imaging element310of the camera device300that captures a subject light image through the imaging optical system and causes the remaining part of the subject light to be incident onto the imaging element120.

A configuration in which the mirror117is removed and light reflected from the beam splitter116is directly incident onto the condenser lens118may be used.

The imaging element120is an area sensor in which plural pixels are two-dimensionally disposed on a light-receiving surface, and outputs an image signal based on each of two subject light images formed on the light-receiving surface. That is, the imaging element120outputs a pair of image signals that shifts from each other in the horizontal direction with respect to one subject light image formed by the imaging optical system.

By using such an area sensor as the imaging element120, compared with a configuration in which line sensors are used, it is possible to avoid a difficulty in an operation for accurately matching positions of the line sensors.

Each pixel that outputs one of the pair of image signals that shifts from each other in the horizontal direction, among pixels included in the imaging element120, forms each first signal detection unit that receives one beam among a pair of beams that passes through two different parts arranged in the horizontal direction in a pupil region of the imaging optical system and detects a signal depending on the intensity of received light.

Each pixel that outputs the other one of the pair of image signals that shifts from each other in the horizontal direction, among the pixels included in the imaging element120, forms each second signal detection unit that receives the other beam among the pair of beams that passes through two different parts arranged in the horizontal direction in the pupil region of the imaging optical system and detects a signal depending on the intensity of received light.

In this embodiment, the imaging element120is used as the area sensor, but instead of the imaging element120, a configuration in which a line sensor in which plural pixels that form the first signal detection units are two-dimensionally arranged is disposed at a position that faces the lens19R and a line sensor in which plural pixels that form the second signal detection units are two-dimensionally arranged is disposed at a position that faces the lens19R may be used.

The camera device300includes an imaging element310such as a CCD image sensor or a CMOS image sensor disposed on the optical axis K of the lens device100, and an image processing section320that processes an image signal obtained by capturing a subject light image using the imaging element310to generate captured image data.

The lens device100includes a driving section that drives the focus lens111and a system control unit that controls the driving section. Further, the system control unit executes the above-described focusing control program to function as the above-described respective functional blocks.

Signals output from the first signal detection units of the imaging element120correspond to detection signals of the above-described phase difference detection pixels52A. Signals output from the second signal detection units of the imaging element120correspond to detection signals of the above-described phase difference detection pixels52B. In this imaging system, the system control unit of the lens device100functions as a focusing control device.

Hereinafter, an embodiment in which a smart phone with a camera is used as the imaging device will be described.

FIG.16is a diagram showing an appearance of a smart phone200which is an embodiment of the imaging device of the invention. The smart phone200shown inFIG.16includes a flat housing201, and a display input unit204that is disposed on one surface of the housing201and includes a display panel202which is a display unit and an operation panel203which is an input unit, in which the display panel202and the operation panel203are integrally formed.

Further, the housing201includes a speaker205, a microphone206, an operation unit207, and a camera unit208. The configuration of the housing201is not limited thereto, and for example, a configuration in which the display unit and the input unit are independently provided may be employed, or a configuration in which a folding structure or a slide mechanism is provided may be employed.

FIG.17is a block diagram showing the configuration of the smart phone200shown inFIG.16.

As shown inFIG.17, as main components of the smart phone, a wireless communication unit210, the display input unit204, a communication unit211, the operation unit207, the camera unit208, a storage unit212, an external input/output unit213, a global positioning system (GPS) receiving unit214, a motion sensor unit215, a power source unit216, and a main control unit220are provided.

Further, as main functions of the smart phone200, a wireless communication function for performing mobile wireless communication through a base station device BS (not shown) and a mobile communication network NW (not shown) is provided.

The wireless communication unit210performs wireless communication with respect to the base station device BS included in the mobile communication network NW according to a command of the main control unit220. The wireless communication unit210performs transmission and reception of a variety of file data such as sound data or image data, e-mail data, or the like, or performs reception of Web data, streaming data, or the like using the wireless communication.

The display input unit204is a so-called touch panel that displays an image (a static image and a video image), character information, or the like under the control of the main control unit220to visually transmit information to a user, and detects a user operation with respect to the displayed information. The display input unit204includes the display panel202and the operation panel203.

The display panel202uses a liquid crystal display (LCD), an organic electro-luminescence display (OELD), or the like as a display device.

The operation panel203is a device that is placed so that an image displayed on a display surface of the display panel202can be visually recognized and detects one or plural coordinates operated by a user's finger or a stylus. In a case where the device is operated by the user's finger or the stylus, a detection signal generated due to the operation is output to the main control unit220. Then, the main control unit220detects an operation position (coordinates) on the display panel202based on the received detection signal.

As shown inFIG.16, the display panel202and the operation panel203of the smart phone200are integrated and accumulated to form the display input unit204, in which the operation panel203is arranged to completely cover the display panel202.

In a case where such an arrangement is employed, the operation panel203may have a function of detecting a user operation in a region out of the display panel202. In other words, the operation panel203may include a detection region with respect to a portion that overlaps the display panel202(hereinafter, referred to as a display region), and a detection region with respect to an outer edge portion that does not overlap the display panel202(hereinafter, referred to as a non-display region).

The size of the display region and the size of the display panel202may be completely the same, but it is not essential that both of the sizes are the same. Further, the operation panel203may include two sensitive regions of an outer edge portion and an inner portion other than the outer edge portion. Further, the width of the outer edge portion is appropriately set according to the size of the housing201, or the like.

Furthermore, as a position detecting method employed in the operation panel203, any one of a matrix switch type, a resistive film type, a surface acoustic wave type, an infrared type, an inductive coupling type, an electromagnetic capacitance type, or the like may be employed.

The communication unit211includes the speaker205and the microphone206, and converts user's voice input through the microphone206into voice data capable of being processed by the main control unit220and outputs the result to the main control unit220, or decodes voice data received by the wireless communication unit210or the external input/output unit213and outputs the result through the speaker205.

Further, as shown inFIG.16, for example, the speaker205may be placed on the same surface as the surface where the display input unit204is provided, and the microphone206may be placed on a side surface of the housing201.

The operation unit207is a hardware key using a key switch or the like, and receives a command from the user. For example, as shown inFIG.17, the operation unit207is a push button switch that is placed on a side surface of the housing201of the smart phone200, is turned on when being pressed by a finger or the like, and is turned off by a restoring force of a spring or the like when the finger is separated.

The storage unit212stores a control program or control data of the main control unit220, application software, address data in which a name, a telephone number, and the like of a communication partner are associated with each other, data on transmitted or received e-mail, Web data downloaded by a Web browser, or data on downloaded content, and temporarily stores streaming data or the like.

Further, the storage unit212includes an internal storage section217built in the smart phone, and an external storage section218provided with an attachable and detachable memory slot. Each of the respective internal storage section217and the external storage section218that form the storage unit212is realized using a storage medium such as a flash memory type, a hard disk type, a multimedia card micro type memory, a card type memory (for example, MicroSD (registered trademark) memory or the like), a random access memory (RAM), a read only memory (ROM), or the like.

The external input/output unit213serves as an interface with respect to all types of external devices to be connected to the smart phone200, and is configured to be directly or indirectly connected to other external devices through communication or the like (for example, universal serial bus (USB), IEEE1394, or the like) or a network (for example, Internet, wireless local area network (LAN), Bluetooth (registered trademark), radio frequency identification (RFID), Infrared Data Association (IrDA, registered trademark), Ultra Wideband (UWB, registered trademark), ZigBee (registered trademark), or the like).

As an external device to be connected to the smart phone200, for example, a wired or wireless headset, a wired or wireless external charger, a wired or wireless data port, a memory card, a subscriber identity module (SIM) card or a user identity module (UIM) card connected through a card socket, an external audio/video device connected through an audio/video input/output (I/O) terminal, an external audio/video device connected in a wireless manner, a smart phone connected in a wired or wireless manner, a personal computer connected in a wired or wireless manner, a PDA connected in a wired or wireless manner, an earphone, or the like is used.

The external input/output unit213may be configured to transmit data transmitted and received from the external device to respective components in the smart phone200, or to transmit data in the smart phone200to the external device.

The GPS receiving unit214receives GPS signals transmitted from GPS satellites ST1to STn according to a command of the main control unit220, executes a positioning operation process based on the plural received GPS signals, and detects the position of the smart phone200including latitude, longitude and altitude.

When position information can be acquired from the wireless communication unit210or the external input/output unit213(for example, wireless LAN), the GPS receiving unit214can also detect the position using the position information.

The motion sensor unit215includes a triaxial acceleration sensor or the like, for example, and detects a physical movement of the smart phone200according to a command of the main control unit220.

By detecting the physical movement of the smart phone200, a direction and an acceleration where the smart phone200moves are detected. The detection result is output to the main control unit220.

The power source unit216supplies power to be accumulated in a battery (not shown) to respective units of the smart phone200according to a command of the main control unit220.

The main control unit220includes a micro processor, and is operated according to a control program or control data stored in the storage unit212to generally control the respective units of the smart phone200.

Further, the main control unit220has a mobile communication control function for controlling respective units of a communication system and an application processing function in order to perform voice communication or data communication through the wireless communication unit210.

The application processing function is realized as the main control unit220is operated according to application software stored in the storage unit212. As the application processing function, for example, an infrared communication function for controlling the external input/output unit213to perform data communication with an opposing device, an e-mail function for performing transmission and reception of e-mail, a Web browsing function for browsing Web pages, or the like is used.

Further, the main control unit220has an image processing function, for example, for displaying an image on the display input unit204based on image data (data on a still image or a moving image) such as received data or downloaded streaming data. The image processing function refers to a function for decoding the image data, performing image processing with respect to the decoded image data, and displaying an image on the display input unit204, by the main control unit220.

In addition, the main control unit220executes a display control with respect to the display panel202, and an operation detection control for detecting a user operation through the operation unit207or the operation panel203. By executing the display control, the main control unit220displays an icon for starting up application software or a software key such as a scroll bar, or displays a window for creating an e-mail.

The scroll bar refers to a soft key for receiving, with respect to an image which cannot be accommodated in a display region of the display panel202, a command for movement of a display portion of the image.

Further, by execution of the operation detection control, the main control unit220detects a user operation through the operation unit207, receives an operation with respect to an icon or an input of a character string with respect to an input section of the window through the operation panel203, or receives a scroll request of a display image through the scroll bar.

Furthermore, by execution of the operation detection control, the main control unit220includes a touch panel control function for determining whether an operation position with respect to the operation panel203is a portion (display region) that overlaps the display panel202or an outer edge portion (non-display region) that does not overlap the display panel202, and controlling a sensitive region of the operation panel203and a display position of a soft key.

The main control unit220may detect a gesture operation with respect to the operation panel203, and may execute a predetermined function according to the detected gesture operation. The gesture operation does not refer to a typical simple operation, but refers to an operation of drawing a locus using a finger or the like, an operation of simultaneously designating plural positions, or an operation of drawing a locus with respect to at least one of plural positions by combination of the above operations.

The camera unit208includes a configuration other than the external memory control unit20, the recording medium21, the display control unit22, the display unit23, the operation unit14in the digital camera shown inFIG.1.

The captured image data generated by the camera unit208may be stored in the storage unit212, or may be output through the external input/output unit213or the wireless communication unit210.

In the smart phone200shown inFIG.16, the camera unit208is placed on the same surface as that of the display input unit204, but the mounting position of the camera unit208is not limited thereto, and may be a rear surface of the display input unit204.

Further, the camera unit208may be used for various functions of the smart phone200. For example, an image acquired by the camera unit208may be displayed on the display panel202, or the image of the camera unit208may be used as one of operation inputs through the operation panel203.

Further, when detecting the position using the GPS receiving unit214, it is possible to detect the position with reference to the image from the camera unit208. In addition, it is possible to determine an optical axis direction or a current usage environment of the camera unit208of the smart phone200without using the triaxial acceleration sensor or by using the triaxial acceleration sensor together with reference to the image from the camera unit208. Further, the image from the camera unit208may be used in the application software.

Furthermore, position information acquired by the GPS receiving unit214, voice information (which may be text information obtained by performing voice text conversion by the main control unit or the like) acquired by the microphone206, posture information acquired by the motion sensor unit215, or the like may be added to the image data on a still image or a moving image, and the result may be recorded in the storage unit212, or may be output through the external input/output unit213or the wireless communication unit210.

As described above, this specification discloses the following content.

(1) A focusing control device comprising: a sensor that has a pair of a first signal detection unit that receives one of a pair of beams passed through different parts disposed in one direction in a pupil region of an imaging optical system including a focus lens and detects a signal depending on an intensity of received light and a second signal detection unit that receives the other of the pair of beams and detects a signal depending on an intensity of received light, in which a plurality of the pairs that are arranged in the one direction form a pair line and a plurality of the pair lines are arranged in a direction orthogonal to the one direction; an addition correlation operation unit that performs a correlation operation between a first signal group obtained by adding up detection signals detected by the first signal detection units of which positions in the one direction are the same, included in the plurality of pair lines, and a second signal group obtained by adding up detection signals detected by the second signal detection units of which positions in the one direction are the same, included in the plurality of pair lines; a non-addition correlation operation unit that performs, for each of the plurality of pair lines, a correlation operation between a detection signal group detected by the first signal detection units included in the pair line and a detection signal group detected by the second signal detection units included in the pair line; a selection unit that calculates a matching rate between first result information of the correlation operation performed by the addition correlation operation unit and second result information of the correlation operation performed by the non-addition correlation operation unit, and selects any one of the first result information or the second result information on the basis of the matching rate; and a lens driving section that drives the focus lens on the basis of the result information selected by the selection unit.

(2) The focusing control device according to (1), wherein the selection unit selects the first result information in a case where the matching rate exceeds a matching threshold value, and selects the second result information in a case where the matching rate is equal to or smaller than the matching threshold value.

(3) The focusing control device according to (2), wherein the selection unit variably controls the matching threshold value.

(4) The focusing control device according to (3), wherein the selection unit sets the matching threshold value to be smaller as a brightness of a subject imaged through the imaging optical system is darker.

(5) The focusing control device according to (3), wherein the selection unit sets the matching threshold value to be smaller as an imaging sensitivity of an imaging device that images a subject through the imaging optical system is higher.

(6) The focusing control device according to any one of (1) to (5), wherein the first result information is information indicating a relationship between a shift amount in a case where the first signal group and the second signal group shift in the one direction by a predetermined shift amount and a correlation value of the first signal group and the second signal group in the shift amount, the second result information is information obtained by adding up or averaging information for each of the plurality of pair lines indicating a relationship between a shift amount in a case where the two detection signal groups shift in the one direction by a predetermined shift amount and a correlation value of the two detection signal groups in the shift amount, and the matching rate is an index indicating a similarity between a shape of a graph indicated by the first result information and a shape of a graph indicated by the second result information.

(7) The focusing control device according to any one of (1) to (6), further comprising: a reliability determination unit that determines a reliability of the first result information, wherein the selection unit selects any one of the first result information or the second result information on the basis of the matching rate in a case where the reliability is equal to or smaller than a reliability threshold value, and selects the first result information in a case where the reliability exceeds the reliability threshold value.

(8) The focusing control device according to any one of (1) to (6), further comprising: a defocus amount calculation unit that calculates a defocus amount on the basis of the first result information, wherein the selection unit selects any one of the first result information or the second result information on the basis of the matching rate in a case where the defocus amount is equal to or smaller than a defocus threshold value, and selects the first result information in a case where the defocus amount exceeds the defocus threshold value.

(9) An imaging device comprising: the focusing control device according to any one of (1) to (8); and an imaging element that images a subject through the imaging optical system including the focus lens.

(10) A lens device comprising: the focusing control device according to any one of (1) to (8); and the imaging optical system.

(11) A focusing control method for controlling a position of a focus lens, using a sensor that has a pair of a first signal detection unit that receives one of a pair of beams passed through different parts disposed in one direction in a pupil region of an imaging optical system including the focus lens and detects a signal depending on an intensity of received light and a second signal detection unit that receives the other of the pair of beams and detects a signal depending on an intensity of received light, in which a plurality of the pairs that are arranged in the one direction form a pair line and a plurality of the pair lines are arranged in a direction orthogonal to the one direction, the method comprising: an addition correlation operation step of performing a correlation operation between a first signal group obtained by adding up detection signals detected by the first signal detection units of which positions in the one direction are the same, included in the plurality of pair lines, and a second signal group obtained by adding up detection signals detected by the second signal detection units of which positions in the one direction are the same, included in the plurality of pair lines; a non-addition correlation operation step of performing, for each of the plurality of pair lines, a correlation operation between a detection signal group detected by the first signal detection units included in the pair line and a detection signal group detected by the second signal detection units included in the pair line; a selection step of calculating a matching rate between first result information of the correlation operation performed in the addition correlation operation step and second result information of the correlation operation performed in the non-addition correlation operation step, and selecting any one of the first result information or the second result information on the basis of the matching rate; and a lens drive step of driving the focus lens on the basis of the result information selected in the selection step.

(12) The focusing control method according to (11), wherein in the selection step, in a case where the matching rate exceeds a matching threshold value, the first result information is selected, and in a case where the matching rate is equal to or smaller than the matching threshold value, the second result information is selected.

(13) The focusing control method according to (12), wherein in the selection step, the matching threshold value is variably controlled.

(14) The focusing control method according to (13), wherein in the selection step, the matching threshold value is set to be smaller as a brightness of a subject imaged through the imaging optical system is darker.

(15) The focusing control method according to (13), wherein in the selection step, the matching threshold value is set to be smaller as an imaging sensitivity of an imaging device that images a subject through the imaging optical system is higher.

(16) The focusing control method according to any one of (11) to (15), wherein the first result information is information indicating a relationship between a shift amount in a case where the first signal group and the second signal group shift in the one direction by a predetermined shift amount and a correlation value of the first signal group and the second signal group in the shift amount, the second result information is information obtained by adding up or averaging information for each of the plurality of pair lines indicating a relationship between a shift amount in a case where the two detection signal groups shift in the one direction by a predetermined shift amount and a correlation value of the two detection signal groups in the shift amount, and the matching rate is an index indicating a similarity between a shape of a graph indicated by the first result information and a shape of a graph indicated by the second result information.

(17) The focusing control method according to any one of (11) to (16), further comprising: a reliability determination step of determining a reliability of the first result information, wherein in the selection step, in a case where the reliability is equal to or smaller than a reliability threshold value, any one of the first result information or the second result information is selected on the basis of the matching rate, and in a case where the reliability exceeds the reliability threshold value, the first result information is selected.

(18) The focusing control method according to any one of (11) to (16), further comprising: a defocus amount calculation step of calculating a defocus amount on the basis of the first result information, wherein in the selection step, in a case where the defocus amount is equal to or smaller than a defocus threshold value, any one of the first result information or the second result information is selected on the basis of the matching rate, and in a case where the defocus amount exceeds the defocus threshold value, the first result information is selected.

(19) A focusing control program that causes a computer to execute a focusing control method for controlling a position of a focus lens, using a sensor that has a pair of a first signal detection unit that receives one of a pair of beams passed through different parts disposed in one direction in a pupil region of an imaging optical system including the focus lens and detects a signal depending on an intensity of received light and a second signal detection unit that receives the other of the pair of beams and detects a signal depending on an intensity of received light, in which a plurality of the pairs that are arranged in the one direction form a pair line and a plurality of the pair lines are arranged in a direction orthogonal to the one direction, the method comprising: an addition correlation operation step of performing a correlation operation between a first signal group obtained by adding up detection signals detected by the first signal detection units of which positions in the one direction are the same, included in the plurality of pair lines, and a second signal group obtained by adding up detection signals detected by the second signal detection units of which positions in the one direction are the same, included in the plurality of pair lines; a non-addition correlation operation step of performing, for each of the plurality of pair lines, a correlation operation between a detection signal group detected by the first signal detection units included in the pair line and a detection signal group detected by the second signal detection units included in the pair line; a selection step of calculating a matching rate between first result information of the correlation operation performed in the addition correlation operation step and second result information of the correlation operation performed in the non-addition correlation operation step, and selecting any one of the first result information or the second result information on the basis of the matching rate; and a lens drive step of driving the focus lens on the basis of the result information selected in the selection step.

According to the present invention, it is possible to provide a focusing control device, a lens device, an imaging device, a focusing control method, and a focusing control program capable of calculating a phase difference suitable for a subject to enhance the accuracy of a focusing control.

As described above, the invention has been described with reference to specific embodiments, but the invention is not limited to the embodiments, and various modifications may be made in a range without departing from the concept of the disclosed invention.

Priority is claimed to Japanese Patent Application No. 2016-077550, filed Apr. 7, 2016, the entire content of which is incorporated herein by reference.