JP4659700B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus capable of performing flange back adjustment according to a use environment and a control method thereof.

  Some conventional camera devices have a function of electrically adjusting the flange back (see, for example, Patent Document 1). In addition, there is a camera that can perform stable photographing without being affected by a temperature change in a use environment (for example, see Patent Document 2). In addition, there is a lens device having means for correcting a difference between the flange back information of the camera device mounted at the time of assembly adjustment of the lens device and the flange back information of the camera device to which the lens device is currently mounted (for example, And Patent Document 3).

JP 2000-121911 A JP 2003-131103 A Japanese Patent Application Laid-Open No. 11-084501

  However, when the flange back information set for the interchangeable lens device and the flange back information set for the camera device are combined, an error occurs between the flange back adjustment value and the ideal value. Also, an error occurs between the flange back adjustment value and the ideal value due to the influence of the temperature change in the use environment. In order to cope with both of these errors, it is the most effective means that the user performs flange back adjustment automatically or manually and obtains an adjustment value for each use environment. However, there is a problem in that the user is subjected to a load of performing flange back adjustment for each use environment.

  Accordingly, an object of the present invention is to avoid the load of the user performing flange back adjustment for each use environment.

An image pickup apparatus according to the present invention is an image pickup apparatus to which a lens device including a drive lens that can be driven can be mounted, and a flange back adjustment control unit that performs drive control for flange back adjustment on the drive lens; Based on the result of drive control on the drive lens by the flange back adjustment control means, adjustment value calculation means for calculating an adjustment value for correcting flange back adjustment, and a history of adjustment values calculated by the adjustment value calculation means And a predicting means for predicting an adjustment value under any use environment based on a history of adjustment values.
An image pickup apparatus control method according to the present invention is a method for controlling an image pickup apparatus to which a lens apparatus including a drive lens that can be driven can be attached, and performs a drive control for flange back adjustment on the drive lens. Calculated by the adjustment control step, the adjustment value calculation step for calculating the adjustment value for correcting the flange back adjustment based on the result of the drive control for the drive lens by the flange back adjustment control step, and the adjustment value calculation step A recording step of recording the adjustment value history on a recording medium, and a prediction step of predicting the adjustment value under any use environment based on the adjustment value history.

  In the present invention, it is possible to calculate an adjustment value for correcting the flange back adjustment under any use environment based on the history of adjustment values calculated in the past. Therefore, according to the present invention, it is possible to avoid the load of the user performing flange back adjustment for each use environment.

  Hereinafter, an embodiment in which the present invention is applied to a digital video camera will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an electrical circuit configuration of a digital video camera according to an embodiment of the present invention. In FIG. 1, a light beam from a subject passes through a first lens group, a variator lens group 2 as a second lens group, a diaphragm 3, a third lens group 4, and a focus lens group 5 as a fourth lens group. Then, an image is formed on the image pickup devices 21 to 23 such as a CCD in the video camera main body 31.

  The first lens group 1 is a lens group to which an optical system in the interchangeable lens unit 12 is fixed. The variator lens group 2 is a lens group for performing zooming. The second lens group 4 is a lens group that is fixed in the same manner as the first lens group 1. The focus lens group 5 is a lens group that has both a focus adjustment function and a competition function that corrects the movement of the focus due to zooming.

  On the image sensor 21, a red component separated by a color separation prism (not shown) in the video camera main body 31 of the light beam incident through the focus lens group 5 is imaged. On the image sensor 22, a green component separated by a color separation prism (not shown) in the video camera main body 31 among the light beams incident through the focus lens group 5 is imaged. On the image sensor 23, a blue component separated by a color separation prism (not shown) in the video camera main body 31 among the light beams incident through the focus lens group 5 is imaged.

  The absolute position of each of the variator lens group 2 and the focus lens group 5 is detected by an absolute position detection device (not shown) such as an encoder, and the detected information is stored in the lens microcomputer 10 as the control means of the interchangeable lens unit 12. Supplied.

  The respective images on the image sensors 21, 22, and 23 are photoelectrically converted, amplified to optimum levels by the amplifiers 25, 26, and 27, and input to the camera signal processing circuit 28 to be standard television signals (video signals). Is converted to At the same time, AF information is read as data by the AF data reading program unit of the main body microcomputer 29 as the control means of the video camera main body 31 as an AF evaluation value.

  The AF evaluation value read by the main body microcomputer 29 is combined with information on the switch on the video camera main body 31 side such as the ON / OFF state of the AF switch (not shown) and the state of the zoom switch (not shown). The data is transferred to the lens microcomputer 10 through the lens side contact 11.

  The lens microcomputer 10 sends a signal to the zoom motor driver 7 to drive the variator lens group 2 in the direction in which TELE or WIDE is pressed when the zoom switch is pressed according to information from the main body microcomputer 29. As a result, the lens microcomputer 10 drives the variator lens group 2 via the zoom motor (lens driving means) 6. At the same time, the lens microcomputer 10 sends a signal to the focus motor driver 9 based on the lens cam data as control information stored in advance in the internal cam data storage unit, and the focus lens via the focus motor (lens driving means) 8. Move group 5. As a result, it is possible to perform a zooming operation without focusing.

  By the way, in the type in which the correction lens (focus lens group 5) is located behind the optical axis rather than the variable magnification lens (variator lens group 2) as in the present embodiment, the focus at the time of variable magnification is maintained. The control position of the correction lens changes depending on the subject distance.

  As shown in FIG. 6A, the lens cam data is for each of a plurality of absolute positions of the variator lens group 2 and for each absolute position of the subject distance (for example, every 1 m and 2 m in FIG. 6A). The position of the focus lens group 5 is stored.

  The lens microcomputer 10 determines the rotation direction and rotation speed of the focus motor 8 using lens cam data selected by the absolute position information of the variator lens group 2 and the focus lens group 5 detected by a position detection device (not shown). To do.

  When the AF switch on the video camera main body 31 side is ON, the AF control unit in the lens microcomputer 10 sends a signal to the focus motor driver 9 so that the AF evaluation value from the main body microcomputer 29 is maximized. Thus, the automatic focus adjustment operation is performed by moving only the focus lens group 5.

  Now, regarding the driving of the correction lens (focus lens group 5) based on the lens cam data as described above, the origin for ensuring accurate back focus must be determined. The origin is determined by correcting with a predetermined correction value based on the set reference position. The predetermined correction value here is a total value of the correction value possessed by the interchangeable lens unit 12 and the correction value transmitted from the video camera main body 31.

  The correction value possessed by the interchangeable lens unit 12 is a fixed value due to variations or the like generated at the stage of manufacturing the interchangeable lens unit 12, and a variable value due to a temperature change or the like on the optical system side. And the total value.

  The correction value transmitted from the video camera main body 31 is a fixed value due to variations or the like generated at the stage of manufacturing the video camera main body 31 and an output signal detected by the temperature detection element 24 on the video camera main body 31 side. It is the value obtained by using. This value is a value given as change information of the flange back on the video camera body 31 side.

  This embodiment relates to a flange back adjustment method for obtaining an adjustment value for correcting an error generated when a correction value possessed by the interchangeable lens unit 12 itself and a correction value transmitted from the video camera main body 31 are combined. is there.

  FIG. 2 is a diagram illustrating an example of a menu screen according to the present embodiment. Here, the adjustment value initialization 203 is a selection item for returning the flange back information of the video camera body 31 to the setting value at the time of factory shipment.

  FIG. 3 is a flowchart showing the flange back adjustment method in the present embodiment. In AF (autofocus) adjustment, in the first step S301, the lens microcomputer 10 moves the variator lens group 2 to the TELE end. In subsequent step S302, the lens microcomputer 10 automatically moves and focuses the focus lens group 5.

  In subsequent step S303, the lens microcomputer 10 moves the variator lens group 2 to the WIDE end while maintaining the focus position.

  In subsequent step S304, the lens microcomputer 10 reads the current focus position, that is, the focus position f1 at the TELE end.

  In subsequent step S305, the lens microcomputer 10 automatically moves and focuses the focus lens group 5.

  In subsequent step S306, the lens microcomputer 10 reads the current focus position, that is, the focus position f2 at the WIDE end.

  The main body microcomputer 31 calculates an adjustment value using (f1-f2) and the lens coefficient set in the interchangeable lens unit 12 (step S307). The video camera body 31 stores a value obtained by adding the flange back information set at the stage of manufacturing the video camera body 31 and the adjustment value as a new adjustment value. Alternatively, a value obtained by summing the flange back information stored as a result of the user performing flange back adjustment on the interchangeable lens unit 12 before and the adjustment value may be stored as a new adjustment value. Good.

  It is possible to correct an error of the flange back that occurs when the interchangeable lens unit 12 and the video camera body 31 are combined by sequentially sending the adjustment value obtained here with correction by temperature to the lens unit 12. It becomes possible.

  In MF (manual focus) adjustment, in the first step S301, the lens microcomputer 10 moves the variator lens group 2 to the TELE end. In the subsequent step S302, after the focus lens group 5 is manually moved and focused, the process proceeds to the next processing by the enter key operation.

  In subsequent step S303, the lens microcomputer 10 moves the variator lens group 2 to the WIDE end while maintaining the focus position set in step S302.

  In subsequent step S304, the lens microcomputer 10 reads the current focus position, that is, the focus position f1 at the TELE end.

  In subsequent step S305, the focus lens group 5 is manually moved and focused, and then the process proceeds to the next process by the enter key operation.

  In subsequent step S306, the lens microcomputer 10 reads the current focus position, that is, the focus position f2 at the WIDE end.

  The video camera body 31 calculates an adjustment value using (f1-f2) and the lens coefficient set in the interchangeable lens unit 12 (step S307). The video camera body 31 stores a value obtained by adding the flange back information set at the stage of manufacturing the video camera body 31 and the adjustment value as a new adjustment value in the video camera body 31. Alternatively, the video camera main body 31 uses a value obtained by summing the flange back information stored as a result of the user's previous flange back adjustment for the interchangeable lens unit 12 and the adjustment value as a new adjustment value. May be stored. The adjustment value obtained here is corrected by temperature and sent to the lens unit 12 sequentially to correct the error of the flange back that occurs when the interchangeable lens unit 12 and the video camera body 31 are combined. It becomes possible.

  FIG. 4 is a flowchart showing a flange back adjustment method including a user operation prohibiting operation in AF adjustment which is one of the flange back adjustments in the present embodiment. FIG. 5 is a sequence chart showing the operational relationship among the operation unit, video camera body, and lens unit at this time. This process is started when 201 in FIG. 2 is selected.

  In the AF adjustment, processing is started in a state where all operations other than the cancel operation, such as zoom operation, focus operation, iris operation, shutter speed operation, etc., are not accepted (steps S501 and S502).

  In the first step S401, a control signal for forcibly shifting to the AF mode and a control signal for moving the variator lens group 2 to the TELE end are transmitted from the main body microcomputer 29 to the lens microcomputer 10 (step S503). ).

  The lens microcomputer 10 moves the variator lens group 2 to the TELE end. In step S402, the lens microcomputer 10 determines whether or not the TELE end has been reached, and repeats the operation in step S401 until the TELE end is reached. When the TELE end is reached, the lens microcomputer 10 sends a signal indicating that the variator lens group 2 has reached the TELE end to the main body microcomputer 29 (step S504).

  Receiving this, the main body microcomputer 29 transmits to the lens microcomputer 10 a signal for confirming whether or not focusing by AF is completed (step S505). In step S403, the lens microcomputer 10 automatically moves and focuses the focus lens group 5. Note that the determination in step S403 is repeated until focusing is completed. After completion of focusing, the lens microcomputer 10 transmits a signal indicating that focusing is completed to the main body microcomputer 29 (step S506).

  A control signal for forcibly shifting to the MF mode and a control signal for moving the variator lens group 2 to the WIDE end are transmitted from the main body microcomputer 29 to the lens microcomputer 10 (step S507). In step S404, the lens microcomputer 10 that has received these control signals moves the variator lens group 2 to the WIDE end while maintaining the focus position at that time.

  In step S405, the lens microcomputer 10 determines whether or not the WIDE end has been reached, and the operation in step S404 is repeated until the WIDE end is reached. When reaching the WIDE end, the lens microcomputer 10 transmits a signal indicating that the variator lens group 2 has reached the WIDE end to the main body microcomputer 29 (step S508).

  The main body microcomputer 29 transmits a signal for confirming the current focus position, that is, the focus position f1 at the TELE end, to the lens microcomputer 10 (step S509). The lens microcomputer 10 transmits a signal indicating the focus position f1 to the main body microcomputer 29 (step S510).

  In step S406, the main body microcomputer 29 receives a signal indicating the focus position f1 from the lens microcomputer 10 and stores it (step S511).

  Subsequently, the main body microcomputer 29 transmits a control signal for forcibly shifting to the AF mode and a signal for confirming that focusing by AF has been completed to the lens microcomputer 10 (step S512).

  The lens microcomputer 10 that has received these signals automatically moves and focuses the focus lens group 5 in step S407, and returns a signal indicating the in-focus state to the main body microcomputer 29 (step S513). Note that the focusing process in step S407 is repeated until focusing is completed.

  The main body microcomputer 29 that has received the in-focus completion signal transmits a signal for confirming the current focus position, that is, the focus position f2 at the WIDE end, to the lens microcomputer 10 (step S514). The lens microcomputer 10 transmits a signal indicating the focus position f2 to the main body microcomputer 29 (step S515). In step S409, the main body microcomputer 29 receives a signal indicating the focus position f2 from the lens microcomputer 10 and stores it.

  In subsequent step S410, the main body microcomputer 29 calculates an adjustment value using (f1-f2) and the lens coefficient set in the interchangeable lens unit 12 (step S516). The video camera body 31 stores a value obtained by adding the flange back information set at the stage of manufacturing the video camera body 31 and the adjustment value as a new adjustment value. Alternatively, a value obtained by summing the flange back information stored as a result of the user performing flange back adjustment on the interchangeable lens unit 12 before and the adjustment value may be stored as a new adjustment value. Good.

  As soon as the processing is finished, the main body microcomputer 29 cancels the state in which all operations other than the cancel operation are not accepted (step S517). The adjustment value obtained here is corrected by temperature and transmitted sequentially to the lens unit 12. As a result, it is possible to correct a flange back error that occurs when the interchangeable lens unit 12 and the video camera body 31 are combined. By the above control, erroneous adjustment is prevented.

  Next, how the adjustment value obtained in the above processing is processed on the interchangeable lens unit 12 side will be described. The adjustment value sent from the main body microcomputer 29 is subjected to predetermined processing as a correction value in the lens microcomputer 10. The lens microcomputer 10 stores lens cam data as ideal values (design values) as shown in FIG. The following calculation is performed for the correction.

  If the adjustment value (flange back change information) transmitted from the video camera main body 31 side is positive, the back focus is extended beyond the ideal value. Accordingly, as shown in FIG. 6B, the lens cam data is read in parallel (downward) with lens cam data indicated by a dotted line obtained by subtracting this amount from the ideal value of lens cam data. By performing lens movement control based on the new data that has been replaced, accurate zooming that does not cause blurring can be performed. If the adjustment value is negative, the back focus is contracted from the ideal value, and the lens cam data is re-read with a parallel shift upward.

  FIG. 7 is a relationship diagram between the temperature and the adjustment value obtained by performing the flange back adjustment in the present embodiment under a plurality of environments. As an example of a method for calculating an adjustment value under the current usage environment using regression analysis based on this accumulated data, a calculation method using approximation to a quadratic equation by the least square method will be described below.

When n sets of data (x _i , y _i ) are approximated to the regression equation y = ax + bx ² , a and b can be obtained by solving the simultaneous equations of Equation 1.

  For Equation 1, the coefficient matrix and constant vector are as shown in Equation 2.

  The coefficient matrix of Equation 2 is converted into a determinant and is defined as D.

  The column corresponding to a in the coefficient matrix is replaced with a constant vector, converted into a determinant, and set as Δa.

  A column corresponding to b of the coefficient matrix is replaced with a constant vector, converted into a determinant, and set as Δb.

  From the above, a and b can be obtained as follows.

  A quadratic expression obtained by the above processing is shown in FIG. The storage unit 32 in FIG. 1 stores arbitrary information (such as a history of adjustment values) obtained by flange back adjustment.

  As an example of a method for evaluating the adjustment value obtained by the above processing, an evaluation method using temperature data and an evaluation method using Euclidean distance are described below.

  FIG. 9 is a flowchart illustrating an example of a technique for evaluating reliability using comparison of temperature data. The first step S901 is the regression analysis process described above. In the next step S902, the main body microcomputer 29, among the temperature data stored in association with the adjustment value in the storage unit 32, the temperature data closest to the temperature data T1 in the current use environment where the adjustment value is predicted. Search for items with T2 (including matching ones).

  In subsequent step S903, the main body microcomputer 29 evaluates whether the absolute value of the difference between T1 and T2 is within an arbitrary threshold value P. If it is within an arbitrary threshold value, it is determined that the reliability of the adjustment value N obtained in step S901 is high, and processing for setting N in the system is performed (step S904). If it exceeds the arbitrary threshold value, it is determined that the reliability of the adjustment value N obtained in step S901 is low, and after N is set in the system, processing for prompting the user to readjust is performed (step S905).

  With the above processing, the reliability of the adjustment value N obtained by the regression analysis can be evaluated. In this example, the temperature data is used as a comparison reference, but it goes without saying that there is no problem if it is replaced with an adjustment value corresponding to the temperature data.

  FIG. 10 is a flowchart illustrating an example of a technique for evaluating reliability using the Euclidean distance. The first step S1001 is the regression analysis process described above. As a result, the obtained quadratic curve is shown in FIG. 11, and the coordinates (x, y) are coordinate points indicating the relationship between the adjustment value and the temperature data in an arbitrary use environment where the adjustment value is predicted. Suppose there is.

  In step S1002, the main body microcomputer 29 calculates the Euclidean distance from the neighboring points in order to calculate the reliability of the derived adjustment value. Expressions for obtaining the Euclidean distance (a, b, c in FIG. 11) are given by the following expressions 7, respectively.

  Here, it is assumed that the smallest Euclidean distance obtained is b. That is, b is a coordinate point closest to the coordinates (x, y) among the coordinate points indicating the relationship between the temperature data stored in association with the storage unit 32 and the evaluation value. The main body microcomputer 29 evaluates whether the obtained Euclidean distance b (L) is within an arbitrary threshold value P (step S1003). If it is within an arbitrary threshold value, it is determined that the reliability of the adjustment value N obtained in step S1001 is high, and processing for setting N in the system is performed (step S1004). If it exceeds the arbitrary threshold value, it is determined that the reliability of the adjustment value N obtained in step S1001 is low, and after N is set in the system, processing for prompting the user to readjust is performed (step S1005). With the above processing, the reliability of the adjustment value N obtained by the regression analysis can be evaluated.

  As described above, according to the present embodiment, an adjustment value under an arbitrary use environment can be obtained by performing regression analysis based on arbitrary information such as temperature and adjustment value at the time of flange back adjustment accumulated in the past. It can be set automatically. This eliminates the need for the user to perform flange back adjustment each time the usage environment changes, and the load on the user can be reduced. Further, when it is determined that the reliability of the adjustment value obtained by the evaluation unit is low, it is possible to prompt the user to adjust the flange back.

  Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and a computer such as the system reads and executes the program codes from the storage medium. Is also achieved.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  In addition, the case where the functions of the above-described embodiment are realized by performing part or all of the actual processing by an OS or the like running on the computer based on the instruction of the program code read by the computer. It is.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion unit connected to the computer, the CPU or the like performs actual processing based on the instruction of the program code, and the above-described processing is performed. The case where the functions of the embodiment are realized is also included.

It is a block diagram which shows the electric circuit structure of the digital video camera which concerns on embodiment of this invention. It is a figure which shows an example of the menu screen in embodiment of this invention. It is a flowchart which shows the flange back adjustment method in embodiment of this invention. It is a flowchart which shows the flange back adjustment method including the prohibition operation | movement of the user operation in AF adjustment. It is a sequence chart which shows the operation | movement relationship between the operation part at the time of the flange back adjustment process including the prohibition operation | movement of a user operation in AF adjustment, a video camera main body, and an interchangeable lens unit. It is a figure for demonstrating the lens movement control performed by correct | amending lens cam data. It is a figure which shows the relationship of temperature and the shift | offset | difference obtained by performing the flange back adjustment in embodiment of this invention. FIG. 8 is a diagram of a quadratic equation obtained as a result of using a predicted value calculation method (least square method) in the embodiment of the present invention for the data group of FIG. 7. It is a flowchart which shows the evaluation method using the temperature data in embodiment of this invention. It is a flowchart which shows the evaluation method using the Euclidean distance in embodiment of this invention. It is a figure which shows the evaluation method using the Euclidean distance in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 4: Fixed lens group 2: Variator lens group 3: Diaphragm 5: Focus lens group 6, 8: Lens drive means 7, 9: Lens drive driver 10: Lens microcomputer 11: Lens side contact 12: Interchangeable lens unit 21 , 22, 23: imaging device 24: temperature detection means 25, 26, 27: amplifier 28: camera signal processing circuit 29: main body microcomputer 30: camera side contact 31: video camera main body 32: storage unit

Claims (7)

An imaging device capable of mounting a lens device including a drive lens that can be driven,
Flange back adjustment control means for performing drive control for flange back adjustment on the drive lens;
Adjustment value calculating means for calculating an adjustment value for correcting the flange back adjustment based on the result of drive control on the drive lens by the flange back adjustment control means;
Recording means for recording a history of adjustment values calculated by the adjustment value calculation means on a recording medium;
An imaging apparatus comprising: a predicting unit that predicts an adjustment value under an arbitrary use environment based on a history of adjustment values.   The imaging apparatus according to claim 1, wherein the prediction unit predicts an adjustment value under an arbitrary use environment by using regression analysis based on a history of the adjustment value.   The imaging apparatus according to claim 1, further comprising an evaluation unit that evaluates the adjustment value predicted by the prediction unit.   The evaluation means calculates the difference between the temperature data in the usage environment in which the adjustment value is predicted by the prediction means and the temperature data that is closest to the temperature data and recorded in association with the adjustment value in the recording medium. The imaging apparatus according to claim 3, wherein the adjustment value predicted by the prediction unit is evaluated according to whether or not the absolute value is within a predetermined threshold.   The evaluation unit includes coordinate points indicating a relationship between the adjustment value predicted by the prediction unit and temperature data in a use environment corresponding to the adjustment value, and temperature data recorded in association with the recording medium, According to whether or not the Euclidean distance with the coordinate point closest to the coordinate point related to the adjustment value predicted by the prediction means is within a predetermined threshold among the coordinate points indicating each relationship with the adjustment value, The imaging apparatus according to claim 3, wherein the adjustment value predicted by the prediction unit is evaluated. A method for controlling an imaging apparatus to which a lens apparatus including a drive lens that can be driven can be attached,
A flange back adjustment control step for performing drive control for flange back adjustment on the drive lens;
An adjustment value calculating step for calculating an adjustment value for correcting the flange back adjustment based on the result of the drive control on the drive lens by the flange back adjustment control step;
A recording step of recording a history of adjustment values calculated in the adjustment value calculation step on a recording medium;
And a prediction step of predicting the adjustment value under any use environment based on the history of the adjustment value.   A non-transitory computer-readable storage medium storing a program for causing a computer to execute the control method for an imaging apparatus according to claim 6.

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