JP5699720B2 - Visual axis angle control device and visual axis angle control method - Google Patents

Description

  The present invention relates to a visual axis angle control device and a visual axis angle control method.

  In an imaging device such as a camera mounted on an aircraft or a ship, a disturbance disturbance may occur in the mounting portion of the imaging device, and the visual axis of the imaging device may change. In such a case, for example, a strap-down method is known as one of the spatially stabilized visual axis control mechanisms that are fixed with respect to the inertial coordinate system so that the visual axis of the imaging apparatus does not change.

  In the strap-down method, an optical system (for example, a mirror or a prism) that can change the visual axis direction is installed in the visual axis direction of the camera, and a gyro is mounted in the vicinity of the imaging device. Then, the visual axis is controlled by moving the optical system in a direction in which the deviation of the visual axis corresponding to the disturbance disturbance detected by the gyro is canceled.

  In addition, a double wedge prism system is known that controls the visual axis angle by combining two wedge prisms in a strap-down space-stabilized visual axis control mechanism. When the double wedge prism method is used, a prism rotation angle directed to a given visual axis angle is obtained so as to cancel the disturbance disturbance detected by the gyro. Here, the visual axis angle means an angle formed by the visual axis with respect to a straight line from the camera to the prism, and the prism rotation angle means a rotation angle around a straight line from the camera to the prism. .

  In order to obtain the prism rotation angle for realizing it from the desired visual axis angle, the following three methods are mainly conceivable. The first method is a method of solving the equation of refraction approximately by repeatedly calculating numerical values. The relationship from the prism rotation angle to the visual axis angle is a three-dimensional refraction formula, that is, a vector expression of Snell's law, which is a nonlinear relational expression including a trigonometric function (normal vector of refraction surface, incident light, outgoing light) Can be expressed as long as the number of refractions is expressed. This is a method of obtaining a solution by repeatedly calculating by changing the prism angle until a desired visual axis angle is obtained.

  The second method is a method using an inverse function of a linearly approximated refraction formula. This is a method of obtaining a prism rotation angle using an inverse function for calculating a prism rotation angle from a visual axis angle after linearly approximating a conversion formula for converting the prism rotation angle to the visual axis angle.

  As a third method, the current visual axis angle is detected, and the prism rotation angle is obtained by feedback about the visual axis angle. For example, the visual axis angle is detected using a beam, a splitter, a beam position sensor, etc., and the prism rotation angle is controlled by feedback on the visual axis angle.

JP 2002-90142 A

However, the conventional techniques described above have the following problems.
In the first method, since it is necessary to repeatedly calculate a three-dimensional vector expression having the number of refractions, there is a problem that it takes a calculation time. Further, the first method and the second method have a problem that the visual axis angle cannot be accurately controlled when there are various errors that affect the visual axis angle control. In other words, in the conventional technology, for example, when there are various errors such as mechanical error, wedge prism refractive index error, wedge prism apex angle error, angle sensor error, etc., these errors control the visual axis angle. The visual axis angle cannot be accurately controlled.

  In the third method, that is, the method of detecting the visual axis angle using a sensor or the like, since the sensor or the like for detecting the visual axis angle is incorporated in the apparatus, it may be difficult to implement due to problems such as space. In addition, in the method of calculating the prism rotation angle using the inverse function described above, an error is generated according to the error of linear approximation, the error in the large visual axis angle range is large, and high-accuracy calculation cannot be performed.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object thereof is to accurately control the visual axis angle.

  In order to solve the above-described problems and achieve the object, this apparatus is obtained from an actual measurement value of the visual axis angle of the imaging apparatus and an actual measurement value of the prism rotation angle of the wedge prism corresponding to the actual measurement value of the visual axis angle. The visual axis angle is corrected using a binary polynomial approximation formula. Then, the prism rotation angle of the wedge prism is calculated with respect to the corrected visual axis angle using Snell's formula in the paraxial region, and the wedge prism is rotated according to the calculated prism rotation angle.

  The disclosed apparatus has an effect that the visual axis angle can be controlled with high accuracy.

FIG. 1 is a diagram illustrating a hardware configuration of the visual axis angle control device according to the first embodiment. FIG. 2 is a diagram illustrating a double wedge prism. FIG. 3 is a diagram illustrating an arrangement example of the imaging device and the gyro. FIG. 4 is a diagram for explaining a visual axis angle control method by feedforward. FIG. 5 is a block diagram illustrating the configuration of the visual axis angle control device according to the first embodiment. FIG. 6 is a diagram for explaining a measurement example of actual values of the visual axis angle and the prism rotation angle. FIG. 7 is a diagram for explaining the procedure for calculating the parameters of the binary polynomial approximate expression. FIG. 8 is a diagram illustrating a calculation procedure for calculating the prism angle from the command visual axis angle. FIG. 9 is a diagram illustrating processing for calculating a prism angle from a command visual axis angle. FIG. 10 is a flowchart illustrating the processing procedure of the binary polynomial approximate expression calculation process of the computer according to the first embodiment. FIG. 11 is a flowchart illustrating the processing procedure of the visual axis angle control process of the visual axis angle control device according to the first embodiment.

  Embodiments of a visual axis angle control device and a visual axis angle control method according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  In the following embodiments, the configuration and processing flow of the visual axis angle control device according to the first embodiment will be described in order, and finally the effects of the first embodiment will be described.

[Configuration of visual axis angle control device]
First, the configuration of the visual axis angle control device 10 shown in FIG. 1 will be described with reference to FIG. 1 is a diagram illustrating a hardware configuration of a visual axis angle control device according to Embodiment 1. FIG. As shown in FIG. 1, the visual axis angle control device 10 includes a double prism mechanism unit 11 and a double prism control unit 13, and is connected to the imaging device control unit 30 and the gyro 40. Further, as shown in FIG. 1, the visual axis angle control device 10 is communicably connected to a computer 14. The processing of each of these units will be described below.

  The double prism mechanism unit 11 includes prism rotation mechanisms 11a and 12a, prisms 11b and 12b, motors 11c and 12c, angle sensors 11d and 12d, and motor amplifiers 11e and 12e. Although FIG. 1 shows an example in which there are two prisms, the invention is not limited to this, and there may be three or more prisms.

  The prism rotation mechanisms 11a and 12a are mechanisms that enable the prisms 11b and 12b to rotate, and rotate the prisms 11b and 12b on the same rotation axis to scan the visual axis. Note that the prisms 11b and 12b may each include a plurality of prisms for the purpose of correcting chromatic aberration. The prisms 11 b and 12 b are two wedge prisms installed on the visual axis of the imaging device 20, and change the direction of the light beam incident on the imaging device 20. Here, the prisms 11b and 12b which are two wedge prisms are demonstrated using FIG. FIG. 2 is a diagram illustrating a double wedge prism.

As shown in FIG. 2, the prisms 11b and 12b are wedge-shaped wedge prisms having a quadrangular shape for entering a light beam. In the initial state, it is assumed that the prism 12b is disposed in an inverted state with respect to the wedge prism 11b. Further, in FIG. 2, alpha is the prism 11b, shows a prism apex angle of 12b, _{n b} is the refractive index of the prism 11b, 12b. Θ ₁ indicates the prism rotation angle of the prism 11b, and θ ₂ indicates the prism rotation angle of the prism 12b. It is assumed that the prisms 11b and 12b illustrated in FIG. 2 have a prism rotation angle of “0”.

In the wedge prism structure, the two prisms 11b and 12b are rotated by prism rotation mechanisms 11a and 12a (not shown), so that the visual axis is AZ (azimuth) and EL (elevation) orientation. can do. As a result, the light beam can be inclined by a predetermined angle by the prisms 11 b and 12 b, and the incident light beam can be incident at substantially the center position of the imaging device 20. 2, the vector n _i indicates the normal vector on a plane Ai. Further, in FIG. 2, the vector _{q a,} a ray vector entering the plane _{A 1,} the vector _{q b,} a ray vector entering the plane _{A 2,} the vector _{q c,} light rays incident on the plane _{A 3} The vector q _d is a light vector incident on the plane A ₄ . In FIG. 2, a vector q _e is a direction vector of the visual axis.

  Returning to the description of FIG. 1, the motors 11 c and 12 c rotate to drive the prisms 11 b and 12 b, respectively. The angle sensors 11d and 12d detect the prism rotation angles of the prisms 11b and 12b, respectively. The motor amplifiers 11e and 12e supply necessary electric power to the motors 11c and 12c based on a command from the double prism control unit 13.

  The double prism control unit 13 controls the rotation angle about the central axis of the prisms 11b and 12b installed on the visual axis of the imaging device 20 by the visual axis control method by the strap-down method, and thereby the imaging device 20. The direction of the light beam incident on the is controlled. The double prism control unit 13 controls the rotation of the prisms 11b and 12b so that the visual axis of the imaging device 20 does not change due to angular disturbance due to fluctuations or the like. The double prism control unit 13 will be described in detail later with reference to FIG.

  The imaging device 20 captures a predetermined direction and outputs the captured image as image data to an external terminal (not shown). The imaging device control unit 30 controls the timing at which the imaging device 20 captures images. The gyro 40 is installed in the vicinity of the imaging device 20, measures the angular velocity of the visual axis angle, and notifies the double prism control unit 13 of the measured angular velocity.

Here, an arrangement example of the imaging device 20 and the gyro 30 will be described with reference to FIG. FIG. 3 is a diagram illustrating an arrangement example of the imaging device and the gyro. The imaging device 20 images in a predetermined direction. The gyro 40 is installed in the vicinity of the imaging device 20. As shown in FIG. 3, in the visual axis control method using the strap-down method, since the gimbal or the like is not mounted, the drive mechanism can be made small. In FIG. 3, the prisms 11b and 12b are not shown.
In the strap-down method, prisms 11b and 12b that can change the visual axis direction are installed in the visual axis direction of the imaging device 20, and the gyro 40 is mounted in the vicinity of the imaging device. Then, the visual axis is controlled by moving the prisms 11b and 12b in a direction in which the deviation of the visual axis corresponding to the angular velocity detected by the gyro 40 is canceled.

  Here, the visual axis control method in feed forward by the strap-down method will be described with reference to FIG. FIG. 4 is a diagram for explaining a visual axis angle control method by feedforward. As shown in FIG. 4, the visual axis angle is controlled in a direction to cancel the airframe shaking angle in which the imaging device detected by the gyro 40 is mounted. When the gyro 40 detects the angular velocity, a value obtained by integrating the detected angular velocities is used as a command value for the visual axis angle. This value corresponds to a visual axis angle command generated by a visual axis angle command generator 13a described later.

  Hereinafter, returning to FIG. In FIG. 1, a computer 14 calculates parameters. The parameter calculation unit 15 of the computer 14 calculates the visual axis angle by performing a calculation using the Snell's formula (the conversion formula from the prism angle to the visual axis angle) in the paraxial region using the measured value of the prism rotation angle. Then, the parameters of the binary polynomial approximation formula are calculated from the calculated visual axis angle and the actual measured value of the visual axis angle. Then, the parameter calculation unit 15 corrects the actual value of the visual axis angle using the binary polynomial approximate expression, and calculates the parameter of the binary polynomial approximate expression from the corrected visual axis angle and the actual value of the visual axis angle. Then, the parameters of the binary polynomial approximation formula are set to the binary polynomial approximation formula. Note that the actual measurement value of the visual axis angle and the actual measurement value of the prism rotation angle are measured in advance and stored in the storage unit 16 of the computer 14. The storage unit 16 includes, for example, a hard disk drive, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

  Here, measurement of the actual measurement value of the visual axis angle and the actual measurement value of the prism rotation angle will be described. FIG. 6 is a diagram for explaining a measurement example of actual values of the visual axis angle and the prism rotation angle. As illustrated in FIG. 6, the actual measurement value of the visual axis angle and the actual measurement value of the prism rotation angle are measured on the optical surface plate 50 that reduces disturbance vibration. The prism 11b and the prism 12b are installed on the gimbal type biaxial rotating table 70, and are rotatable about the AZ axis and the EL axis as central axes. Further, as illustrated in FIG. 6, the collimator 60 emits parallel rays to the prism 11b and the prism 12b.

  Then, when measuring the actual measurement value of the visual axis angle and the actual measurement value of the prism rotation angle, the prism 11b and the prism 12b are rotated by the gimbal type biaxial rotary table 70 so as to be the determined AZ axis and EL axis. Let Then, the parallel rays emitted from the collimator 60 are allowed to pass through the prism 11b and the prism 12b, and the visual axis angle is measured from the optical axis that has passed. Thus, the measured value of the visual axis angle and the measured value of the prism rotation angle are measured using the determined AZ axis and EL axis and the measured visual axis angle as one set. As described above, the process of discretely measuring the relationship between the prism rotation angle and the visual axis angle is performed in advance.

The parameter calculation unit 15 calculates the parameters of the binary polynomial approximate expression using the measurement values of the visual axis angle and the prism rotation angle thus measured. Here, a method of calculating the parameters of the binary polynomial approximation formula will be described with reference to FIG. FIG. 7 is a diagram for explaining the procedure for calculating the parameters of the binary polynomial approximate expression. First, as shown in FIG. 7 (1), the parameter calculator 15 uses, as reference data, measured values EL and AZ of visual axis angles prepared in advance and measured values θ ₁ and θ of prism rotation angles corresponding thereto. ₂ is read out. Then, as shown in FIG. 7 (2), the parameter calculation unit 15 performs calculation using the Snell formula (the conversion formula from the prism angle to the visual axis angle) in the paraxial region, and is the reference data. The visual axis angles EL ^** and AZ ^** are calculated from the actually measured values θ ₁ and θ _{2 of the} prism rotation angle . Snell's formula (converting formula from prism angle to visual axis angle) in the paraxial region is expressed by the following formulas (1) and (2). Note that S _α means sin _α .

Then, as shown in FIG. 7 (3), the parameter calculation unit 15 uses the simultaneous visual equation 2 based on the calculated visual axis angles EL ^** and AZ ^** and the actual measured values EL and AZ of the visual axis angle as reference data. parameter _c 1 _{to c} n of the original polynomial _{approximation,} to calculate the d 1 to d _n. n is appropriately selected according to the degree of the binary polynomial. For example, in the case of a binary quintic polynomial approximation, n is 21. The following formulas (3) and (4) exemplify fifth-order binary function formulas.

Hereinafter, the case of a binary quintic polynomial approximation will be described. Subsequently, as shown in FIG. 7 (4), the parameter calculation unit 15 measures the visual axis angle, which is the reference data, by Snell's formula (the conversion formula from the visual axis angle to the prism angle) in the paraxial region. The prism angle is obtained from the values EL and AZ . Then, the parameter calculation unit 15 performs a calculation using Snell's formula (a conversion formula from the prism angle to the visual axis angle) in the paraxial region, obtains the visual axis angle from the prism angle, and a binary polynomial approximation formula. using a visual axis angle ^EL *, to calculate the AZ ^*. Snell's formula (conversion formula from visual axis angle to prism angle) in the paraxial region is expressed by the following formulas (5) and (6).

Thereafter, as shown in FIG. 7 (5), the parameter calculation unit 15 uses a binary polynomial approximation formula from the measured values EL and AZ of the visual axis angle, which are reference data, and the calculated visual axis angles EL ^* and AZ ^*. Parameters a _{1 to} a ₂₁ and b _{1 to} b ₂₁ are calculated. The following formulas (7) and (8) exemplify quintic binary function formulas.

Thereby, the calculated parameters a _{1 to} a ₂₁ and b _{1 to} b ₂₁ are set in a binary polynomial approximate expression, and the binary polynomial approximate expression is stored in the predetermined storage unit 16.

  Next, the configuration of the visual axis angle control device 10 will be described with reference to FIG. FIG. 5 is a block diagram illustrating the configuration of the visual axis angle control device 10 according to the first embodiment. The double prism control unit 13 includes a visual axis angle command generator 13a, a visual axis angle prism angle converter 13b, and prism angle controllers 13c and 13d.

  The visual axis angle command generator 13a generates a visual axis angle command to be directed (hereinafter referred to as a visual axis angle command) and notifies the visual axis angle command to the visual axis angle prism angle converter 13b. For example, a command angle command to be directed is generated according to the visual axis shift corresponding to the angular velocity of the visual axis angle detected by the gyro 40, and the visual axis angle command is notified to the visual axis angle prism angle converter 13b. . Here, the visual axis angle command refers to the value of the visual axis angle to be directed together with an instruction to set the visual axis angle to be directed.

The visual axis angle prism angle converter 13b converts the visual axis angle command into a prism angle command. The visual axis angle prism angle converter 13 b includes a setting unit 130, a correction unit 131, and a calculation unit 132.
The setting unit 130 is a binary polynomial approximation obtained from the measured value of the visual axis angle of the imaging device and the measured value of the prism rotation angle of the wedge prism corresponding to the measured value of the visual axis angle from the storage unit 16 of the computer 14. The equation is read and set as a binary polynomial approximation equation used in the correction unit 131.

The correction unit 131 uses the binary polynomial approximate expression obtained from the actual measurement value of the visual axis angle of the imaging device and the actual measurement value of the prism rotation angle of the wedge prism corresponding to the actual measurement value of the visual axis angle, to determine the visual axis angle. Correct. For example, the correction unit 131 corrects the visual axis angle command generated by the visual axis angle command generator 13a using the above equations (7) and (8) as a binary polynomial approximation. In other words, the relationship between the prism rotation angle and the visual axis angle is discretely corrected as described above in order to collectively correct the non-linearity of the relationship between the prism rotation angle and the visual axis angle and the effects of manufacturing and assembly errors. The relationship between the prism rotation angle and the visual axis angle is interpolated with a binary polynomial approximation.

  The calculation unit 132 calculates the prism rotation angle of the wedge prism using the Snell equation in the paraxial region with respect to the corrected visual axis angle. For example, the calculation unit 132 corrects the visual axis angle corrected using the above formulas (5) and (6) as the Snell formula (the conversion formula from the visual axis angle to the prism angle) in the paraxial region. From the above, the prism rotation angles of the wedge prisms 11b and 12b are calculated. Then, the calculation unit 132 notifies the prism angle controllers 13c and 13d of a prism angle command that is a command for rotating the wedge prisms 11b and 12b by the calculated prism rotation angle.

As described above, the visual axis angle control device 10 corrects the visual axis angles EL and AZ using the binary polynomial approximation formula as shown in FIG. 8, and the corrected visual axis angle commands EL and AZ are corrected. The prism rotation angles θ ₁ and θ ₂ of the wedge prism are calculated using Snell's formula (conversion formula from the visual axis angle to the prism angle) in the paraxial region. FIG. 8 is a diagram illustrating a calculation procedure for calculating the prism rotation angle from the command visual axis angle.

That is, as shown in FIG. 9, the visual axis angle control device 10 corrects the visual axis angle command using a binary polynomial approximation formula, thereby correcting the visual axis angle error, that is, mechanical error, wedge prism refraction. The visual axis angles EL and AZ (described as “visual axis angle *” in FIG. 9) corrected for the error of the rate, the wedge prism apex error, the angle sensor error, and the like can be obtained. Then, the visual axis angle control device 10 can accurately correct the visual axis angle error by calculating the prism rotation angle from the visual axis angle using the Snell equation in the paraxial region. The shaft angle can be controlled with high accuracy.

  As described above, the visual axis angle control device 10 corrects the visual axis angle command using the binary polynomial approximate expression calculated from the measured value of the visual axis angle and the measured value of the prism rotation angle. As a result, it is possible to correct a pointing angle error caused by nonlinearity that increases rapidly with an increase in the pointing angle, and a pointing angle error caused by a prism characteristic or an angle sensor error.

  The prism angle controllers 13c and 13d control the prisms 11b and 12b to rotate according to the prism rotation angle calculated by the calculation unit 132. For example, when the prism angle controllers 13c and 13d receive the prism angle command from the visual axis angle prism angle converter 13b, the prism angle controllers 13c and 13d issue a current command to the motor amplifiers 11e and 12e according to the prism rotation angle calculated by the calculation unit 132. Output.

  The motor amplifiers 11e and 12e supply necessary power to the motors 11c and 12c based on the current command. The motors 11c and 12c supply torque for rotating the prism rotation mechanisms 11a and 12a supported by a rotary bearing or the like. When the prisms 11b and 12b rotate, the angle sensors 11d and 12d detect the angles of the prisms 11b and 12b, and input them to the prism angle controllers 13c and 13d as feedback signals.

[Computer processing]
Next, processing performed by the computer 14 according to the first embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating the processing procedure of the binary polynomial approximate expression calculation process of the computer 14 according to the first embodiment. FIG. 11 is a flowchart illustrating the processing procedure of the visual axis angle control process of the visual axis angle control device according to the first embodiment.

As shown in FIG. 10, the parameter calculation unit 15 of the computer 14 reads out the actual measurement value of the visual axis angle prepared in advance and the actual measurement value of the prism rotation angle corresponding thereto as reference data (step S <b> 101, FIG. 7). Corresponding to (1)). For example, the parameter calculation unit 15 reads the actual measurement values EL and AZ of the visual axis angle measured in advance and stored in the storage unit as the reference data, and the actual measurement values θ ₁ and θ ₂ of the corresponding prism rotation angles. .

Then, the parameter calculation unit 15 performs calculation using Snell's formula in the paraxial region, and calculates the visual axis angle from the actually measured value of the prism rotation angle that is the reference data (step S102, FIG. 7 (2)). Corresponding). For example, the parameter calculation unit 15 performs calculation using the Snell equation in the paraxial region, and calculates the visual axis angles EL ^** and AZ ^** from the measured values θ ₁ and θ ₂ of the prism rotation angle, which is the reference data. Is calculated.

Then, the parameter calculation unit 15 calculates the parameters of the binary polynomial approximate expression from the calculated visual axis angle and the actual measurement value of the visual axis angle that is the reference data (corresponding to step S103, FIG. 7 (3)). For example, the parameter calculation unit 15 calculates the parameters c _{1 to} c of the binary polynomial approximate expression by simultaneous equations from the calculated visual axis angles EL ^** and AZ ^** and the actual measured values EL and AZ of the visual axis angle as reference data. ₂₁ and d _{1 to} d ₂₁ are calculated.

Subsequently, the parameter calculation unit 15 calculates the corrected visual axis angle from the visual axis angle of the reference data using a binary polynomial approximation formula (corresponding to step S104, FIG. 7 (4)). For example, the parameter calculation unit 15 obtains the prism angle from the measured values EL and AZ of the visual axis angle, which is the reference data, using Snell's formula in the paraxial region. Then, the computer 14 performs a calculation using the Snell equation in the paraxial region, obtains the visual axis angle from the prism angle , and calculates the visual axis angles EL ^* and AZ ^* using a binary polynomial approximation formula. To do.

Then, the computer 14 calculates the parameters of the binary polynomial approximate expression from the calculated visual axis angle and the visual axis angle of the reference data (corresponding to step S105, FIG. 7 (5)). For example, the parameter calculation unit 15 uses the parameters a _{1 to} a ₂₁ , b _{1 of} the binary polynomial approximation formula based on the actual measurement values EL and AZ of the visual axis angle as reference data and the calculated visual axis angles EL ^* and AZ ^*. to calculate the ~b _21.

Next, the processing procedure of the visual axis angle control process of the visual axis angle control device 10 will be described with reference to FIG. As illustrated in FIG. 11, the correction unit 131 of the visual axis angle control device 10 corrects the command visual axis angle using a binary polynomial approximation formula (step S <b> 201). For example, the correction unit 131 corrects the visual axis angle command generated by the visual axis angle command generator 13a using the above equations (7) and (8) as a binary polynomial approximation.

  Then, the calculation unit 132 calculates the prism rotation angle from the visual axis angle using the Snell equation (step S202). For example, the calculation unit 132 calculates the prism rotation angle of the wedge prisms 11b and 12b from the corrected visual axis angle using the above equation (3) and the following equation (4) as the Snell equation in the paraxial region. To do.

  Subsequently, the prism angle controllers 13c and 13d control the rotation of the prisms 11b and 12b by the calculated prism rotation angle (step S203). For example, when the prism angle controllers 13c and 13d receive the prism angle command from the visual axis angle prism angle converter 13b, the prism angle controllers 13c and 13d issue a current command to the motor amplifiers 11e and 12e according to the prism rotation angle calculated by the calculation unit 132. The rotation is controlled by outputting.

[Effect of Example 1]
As described above, the visual axis angle control device 10 is obtained from the actual measurement value of the visual axis angle of the imaging device and the actual measurement value of the prism rotation angle of the prisms 11b and 12b corresponding to the actual measurement value of the visual axis angle. The visual axis angle is corrected using the original polynomial approximation. Then, the visual axis angle control device 10 calculates the prism rotation angle of the wedge prism using the Snell equation in the paraxial region with respect to the corrected visual axis angle. Thereafter, the visual axis angle control device 10 rotates the prisms 11b and 12b in accordance with the calculated prism rotation angle. As a result, the visual axis angle control device 10 can accurately correct errors in the visual axis angle (for example, mechanical errors, wedge prism refractive index errors, wedge prism apex angle errors, and angle sensor errors). . Thereby, the visual axis angle control apparatus 10 can correct the error of the visual axis angle with high accuracy, and can control the visual axis angle with high accuracy.

  Further, according to the first embodiment, the visual axis angle control device 10 calculates the visual axis angle by performing the calculation using the Snell equation in the paraxial region using the measured value of the prism rotation angle. The parameters of the binary polynomial approximation formula are calculated from the obtained visual axis angle and the measured value of the visual axis angle. Then, the visual axis angle control device 10 corrects the actual measurement value of the visual axis angle using the calculated binary polynomial approximation formula, and performs the binary polynomial approximation from the corrected visual axis angle and the actual measurement value of the visual axis angle. The parameter of the equation is calculated, and the parameter of the binary polynomial approximate equation is set to the binary polynomial approximate equation. For this reason, using the actual measurement value of the visual axis angle and the actual measurement value of the prism rotation angle, errors in the visual axis angle (for example, mechanical error, wedge prism refractive index error, wedge prism apex error, angle sensor error) ) Can be calculated with high accuracy.

  Further, according to the first embodiment, the visual axis angle control device 10 generates and generates a command angle command to be directed according to the visual axis shift corresponding to the angular velocity of the visual axis angle detected by the gyro. The command angle command is corrected using a binary polynomial approximation formula. For this reason, the visual axis angle control device 10 is capable of.

  In addition to the above-described embodiments, the visual axis angle control device may be implemented in various different forms. Therefore, another embodiment included in the present embodiment will be described below as a second embodiment.

(1) Prism In the first embodiment, the case where the visual axis angle control device has two wedge prisms has been described. However, the present embodiment is not limited to this, and there is one wedge prism. There may be three or more. Further, instead of the wedge prism, a mirror or the like may be used as an optical system that can change the visual axis direction.

(2) System Configuration The components of the illustrated devices are functionally conceptual and need not be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, the correction unit 131 and the calculation unit 132 may be integrated. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic. For example, the processing by the computer 14 according to the first embodiment may be performed inside the visual axis angle control device 10 (such as the visual axis angle prism angle converter 13b).

(3) Program The visual axis angle control method described in the present embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. The program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

DESCRIPTION OF SYMBOLS 10 Visual axis angle control apparatus 11 Double prism mechanism part 11a, 12a Prism rotation mechanism 11b, 12b Prism 11c, 12c Motor 11d, 12d Angle sensor 11e, 12e Motor amplifier 13 Double prism control part 13a Visual axis angle command generator 13b Visual axis Angular prism angle converter 13c, 13d Prism angle controller 14 Computer 15 Parameter calculation unit 16 Storage unit 130 Setting unit 131 Correction unit 132 Calculation unit 20 Imaging device 30 Imaging device control unit 40 Gyro 50 Optical surface plate 60 Collimator 70 Gimbal type 2 Axis turntable

Claims (4)

Correction for correcting the visual axis angle using a binary polynomial approximate expression obtained from the actual measured value of the visual axis angle of the imaging apparatus and the measured value of the prism rotation angle of the wedge prism corresponding to the actual measured value of the visual axis angle And
A calculation unit that calculates a prism rotation angle of the wedge prism using a Snell equation in a paraxial region with respect to the visual axis angle corrected by the correction unit;
A rotation control unit that rotates the wedge prism according to the prism rotation angle calculated by the calculation unit;
A visual axis angle control device comprising:   A visual axis angle is calculated by performing a calculation using the Snell equation in the paraxial region using the measured value of the prism rotation angle, and the visual axis angle is calculated from the calculated visual axis angle and the measured value of the visual axis angle. 1 binary polynomial approximation formula is calculated, the measured visual axis angle is corrected using the calculated first binary polynomial approximation formula, and the corrected visual axis angle and the visual axis angle are corrected. A parameter calculation unit that calculates a parameter of the second binary polynomial approximate expression from the actual measurement value of the second binary polynomial approximate expression and sets the parameter of the second binary polynomial approximate expression in the binary polynomial approximate expression; The visual axis angle control device according to claim 1. A visual axis angle generating unit for generating a command of a command angle to be directed according to a shift of the visual axis corresponding to the angular velocity of the visual axis angle detected by the gyro;
The visual axis angle according to claim 1 or 2, wherein the correction unit corrects the command angle command generated by the visual axis angle generation unit using the binary polynomial approximation formula. Control device. A visual axis angle control method for controlling a visual axis angle,
Using the binary polynomial approximate expression obtained from the actual measurement value of the visual axis angle of the imaging device and the actual measurement value of the prism rotation angle of the wedge prism corresponding to the actual measurement value of the visual axis angle, the visual axis angle is corrected,
For the corrected visual axis angle, calculate the prism rotation angle of the wedge prism using Snell's formula in the paraxial region,
A visual axis angle control method, comprising: rotating a wedge prism according to the calculated prism rotation angle.

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