JP2003195148A - Subject distance display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a subject distance display device capable of solving such a problem that an error is produced in a subject distance by a difference in the moving direction of a focusing lens by previously storing the characteristic data for making the position of the focusing lens and the subject distance correspondent to each other in each of the moving directions of the focusing lens and calculating the subject distance from the position of the focusing lens in accordance with the characteristic data meeting the moving direction of the focusing lens. <P>SOLUTION: The characteristic data for making the position of the focusing lens and the subject distance correspondent to each other is previously formed respectively in the case (Figure 3 (A)) the moving direction of the focusing lens is from a closest-distance side to an infinite side and the case (Figure 3 (B)) the moving direction of the focusing lens is from the infinite side to the closest-distance side. In displaying the subject distance, the moving direction of the focusing lens is detected and the subject distance is calculated from the position of the focusing lens by using the characteristic data of this direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subject distance display device, and more particularly to a subject distance display device for displaying the distance of a focused subject in a lens device for a television camera.

[0002]

2. Description of the Related Art In a television lens system used for a television camera for broadcasting, etc., the focus lens (group) of the lens device is moved from the focus lens position currently set, or focus instruction means such as focus demand to the lens device. A subject distance display device has been proposed which acquires a designated focus lens position, obtains a subject distance at the acquired focus lens position, and displays the subject distance (Japanese Patent Application No. 2001-2001).
85136, Japanese Patent Application No. 2001-285236).
In order to obtain the subject distance, it is necessary to associate the focus lens position with the subject distance in advance. For example, the following method is used. First, a measurement object is placed at a certain position, the distance from the lens device to the measurement object is measured, and the focus lens of the lens device is driven to focus on the measurement object. In the subject distance display device, the focus lens position set at that time is acquired from the lens device. Here, the measured value obtained by measuring the distance to the object to be measured is input to the subject distance display device. As a result, the focus lens position set in the lens device at that time is associated with the subject distance. By repeating such an operation while changing the distance of the object to be measured, a plurality of focus lens positions and object distances are associated with each other. Based on this, a distance function indicating the relationship between the focus lens position and the subject distance is obtained, and each point in the variable range of the focus lens position is associated with the subject distance.

[0003]

However, since there is some mechanical / electrical play between the focus lens and the position sensor for detecting the current position of the focus lens, the operating direction of the focus lens (moving direction). )
However, even if the actual setting position of the focus lens is the same, the position of the focus lens detected by the position sensor differs depending on the operation direction, and the error of the displayed subject distance becomes large. Therefore, in the past, the focus lens was always operated in the same direction so as to eliminate the influence of error. However, if there is such a restriction on the operation, the operability becomes poor. was there.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an object distance display device capable of eliminating an error in an object distance caused by a difference in moving direction of a focus lens.

[0005]

In order to achieve the above object, the invention according to claim 1 acquires a focus lens position at which a focus lens of a lens device is currently set, or sets the focus lens position of the focus lens. Focus lens position acquisition means for acquiring the focus lens position instructed by the lens device from the focus instruction means as the position to be set, and characteristic data for associating the focus lens position with the subject distance for each moving direction of the focus lens in advance. Characteristic data storing means stored in the focus lens moving direction detecting means, focus lens moving direction detecting means for detecting a moving direction until the focus lens reaches the focus lens position acquired by the focus lens position acquiring means, and focus lens moving direction detecting means. Focus detected by means Subject data for obtaining the characteristic data about the moving direction of the lens from the characteristic data storage means, and for calculating the subject distance corresponding to the focus lens position obtained by the focus lens position obtaining means on the basis of the obtained characteristic data. It is characterized in that it comprises a calculating means and a display means for displaying the subject distance calculated by the subject distance calculating means.

The invention described in claim 2 is the same as claim 1
In the invention described in, the actual measurement value receiving means for receiving the actual measurement value of the subject distance corresponding to the focus lens position acquired by the focus lens position acquisition means, and when the actual measurement value is received by the actual measurement value receiving means. The movement direction until the focus lens reaches the focus lens position is detected by the focus lens movement direction detecting means, and the actual measurement value received by the actual measurement value receiving means is used as the characteristic data about the detected movement direction. And a characteristic data generation unit that stores the characteristic data in the storage unit in association with the lens position.

According to the present invention, characteristic data associating the focus lens position with the subject distance is stored for each moving direction of the focus lens, and the focus lens position is calculated based on the corresponding data corresponding to the moving direction of the focus lens. Since the subject distance is calculated, the problem that the subject distance has an error due to the difference in the moving direction of the focus lens is eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a subject distance display device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a control block diagram showing the overall configuration of a television lens system to which the present invention is applied. First, a schematic configuration of the lens device 10 used in the television lens system will be described. As is well known, the lens device 10 includes, for example, a zoom lens (group) ZL,
Optical components such as a focus lens (group) FL, an extender lens (group) EL, and an iris I are arranged. In addition, the lens device 10 is provided with a zoom motor ZM, a focus motor FM, an extender motor EM, and an iris motor IM corresponding to each of these optical components, and the power of each motor is supplied to each optical component. Power transmission mechanism (gear train) ZG, FG, E
G and IG are provided. When each motor rotates, each optical component is driven. For example, when the zoom lens ZL is driven by the zoom motor ZM, the shooting magnification changes, and when the focus lens FL is driven by the focus motor FM, the shooting distance (combined distance) is changed. Subject distance to focus) changes.
Extender lens EL by extender motor EM
Is driven, the shooting magnification is, for example, 1 to 2 times, or
When the iris I is driven by the iris motor IM by switching from 2 times to 1 time, the diaphragm position (diaphragm diameter) changes.

On the other hand, the lens device 10 receives a zoom control signal for zoom control, a focus control signal for focus control, and an extender control signal for extender control from the zoom controller ZC, the focus controller FC, and the extender controller EC, respectively. An iris control signal regarding iris control is input from the camera body to which the apparatus 10 is attached. These control signals are, for example, analog signals, and A /
It is converted into a digital signal by the D converter 12.

A CPU 14 is mounted on the lens device 10, and each control signal converted into a digital signal by the A / D converter 12 is input to the CPU 14, and a zoom lens ZL and a focus are also provided. Lens F
The position signals indicating the respective current positions of L, the extender lens EL, and the iris I are the respective potentiometers ZP and F.
Input is made from P, EP, and IP. CP
U14 is a zoom lens ZL, a focus lens FL, an extender lens EL, and an iris I based on respective control signals and position signals relating to zoom, focus, extender, and iris, and a target position or target speed designated by each control signal. So that each motor Z
It outputs drive signals for driving M, FM, EM, and IM.

Here, in general, the zoom control signal indicates a zoom target speed, and the other control signals indicate a target position. Further, the drive signal output from the CPU 14 indicates the rotation speed (including the rotation direction) of each motor.

The drive signal output from the CPU 14 is D
A / A converter 16 converts the analog signal, the drive signal for the zoom motor ZM is input to the zoom amplifier ZA, the drive signal for the focus motor FM is input to the focus amplifier FA, and the extender motor E
The drive signal for M is input to the extender amplifier EA, and the drive signal for the iris motor IM is input to the iris amplifier IA. Each amplifier ZA, FA, E
A and IA control the voltage applied to each corresponding motor so that the rotation speed corresponds to the input drive signal. As a result, the zoom lens ZL and the focus lens F
L, the extender lens EL, and the iris I are set to the target position or target speed designated by each control signal.

In addition to the lens device 10 configured as described above, the subject distance display device 20 according to the present invention is detachably connected to a predetermined communication connector of the lens device 10 by a cable, for example. The subject distance display device 20 according to the present embodiment is not limited to the subject distance.
Since various other lens information is also displayed, it will be referred to as a lens information display device 20 hereinafter. Further, the lens information display device 20 may be detachably fixed to the lens device 10 or the like with a screw or the like. The lens information display device 20 does not have to be a device specially manufactured for displaying lens information, and may be a commercially available computer such as a personal computer (notebook personal computer) or a mobile terminal. Further, the processing of the lens information display device 20 described below is performed by the CPU 14 or the like in the lens device 10 so that the processing is displayed on the display unit installed in the lens device 10 or the like or the display screen of the viewfinder or the like. Good.

The lens information display device 20 is equipped with a CPU 22 and an SCI (serial communication interface) 24 so that it can communicate with an external device. Further, the lens device 10 is also equipped with the SCI 18, which enables communication with an external device. Therefore, the lens information display device 20
When the communication connector of the lens device 10 and the communication connector of the lens device 10 are connected by a cable or the like, the lens information display device 2
The CPU 22 of 0 can exchange signals with the CPU 14 of the lens apparatus 10 by communication. The communication means between the lens information display device 20 and the lens device 10 is not limited to a wire, but may be wireless, and any communication method may be used.

The CPU 22 of the lens information display device 20 is
The CPU 1 of the lens device 10 using such communication means
4, requesting that the required lens information be transmitted, and the CPU 1
The required lens information is acquired from 4. If there is lens information to be displayed on the LCD panel 26 of the lens information display device 20 other than the acquired lens information, the lens information is calculated based on the lens information acquired from the lens device 10, and the LCD panel 26 The lens information to be displayed on the LCD panel 26 is displayed via the display driver 28. The content and display form of the lens information displayed on the LCD panel 26 can be switched by the operator by a predetermined switch of the operation switch section 30, but the description thereof is omitted.

Here, the CPU of the lens information display device 20
The lens information acquired from the lens device 10 at 22 is information that can be recognized by the CPU 14 of the lens device 10. For example, as the lens information, the specification data indicating the optical specifications of the lens device 10 and the model name of the lens device 10, And a zoom lens ZL, a focus lens FL,
There is position data indicating the current set position of the extender lens EL and the iris I. The zoom lens ZL,
The setting positions of the focus lens FL, the extender lens EL, and the iris I are referred to as the zoom lens position, the focus lens position, the extender lens position (extender magnification), and the diaphragm position (diaphragm diameter), respectively.

The specification data includes data unique to the lens device 10 which is necessary when calculating lens information other than the lens information acquired from the lens device 10. The specification data, zoom lens position, and By using the position data indicating the focus lens position, the extender lens position, and the diaphragm position, desired lens information different from the lens information acquired from the lens device 10 can be obtained. In the lens information display device 20, the specification data corresponding to various lens devices is registered in the memory in advance, and the model name of the lens device 10 is acquired instead of acquiring the specification data from the lens device 10. It is also possible to read the specification data corresponding to the model name from the memory, and in the present embodiment, the specification data (characteristic data) described later that is necessary when calculating the subject distance corresponding to the focus lens position is the lens. Information display device 2
0 is stored in the EEPROM 32.

On the other hand, as the lens information displayed on the LCD panel 26 of the lens information display device 20, for example, in addition to the current zoom lens position, focus lens position, extender lens position, aperture position acquired from the lens device 10, Distance, depth of field, focal length, angle of view, F number, T number, and the like. These subject distances,
The lens information such as the depth of field, the focal length, the angle of view, the F number, and the T number can be calculated based on the specification data and the position data acquired from the memory of the lens device 10 or the lens information display device 20. is there.

The information obtained by the lens device 10 and the information calculated from the information are converted into a file, and a user-specified file name (date, scene number, place name, etc.) is designated, and the lens information display device 20 is predetermined. Memory (such as built-in rewritable memory or removable recording medium), and readable,
If necessary, the read information may be displayed on the LCD panel 26 or may be printed out. In this way, for example, in the case of movie production, the focal length and aperture value of the lens device are used properly according to each scene, but when reshooting is performed at a later date, the previous shooting conditions can be easily stored. You can do it, LC
Displaying on the D panel 26 or the like is convenient because it is possible to take another picture under the same shooting conditions as the last time.

FIG. 2 is a view showing an example of lens information displayed on the LCD panel 26. As shown in the figure, information on the model name of the lens device 10 is displayed, for example, as “HA20 × 7.5E” in the portion indicated by reference numeral 40 at the top of the screen. In the portion indicated by the reference numeral 42 below the information on the subject distance, for example, "4.99 m" is displayed, and in the portion indicated by the reference numeral 44 therebelow, the information on the depth of field is indicated, for example, in the front field. The depth is displayed as "-3.18 m" and the rear depth of field is displayed as "+ ∞m". The focal length information, for example, "7.5 mm" is displayed in the portion indicated by the reference numeral 46 below the display of the depth of field, and the angle of view information is further displayed in the portion indicated by the reference numeral 48 therebelow. "65 ° 11 '" for the horizontal direction and "39" for the vertical direction.
32 ° '"is displayed. For example, "2.2" is displayed as the F number information on the left side portion 50 of the subject distance display, and T number information is displayed on the left side portion 52 of the focal length display. Is, for example, “2.
4 ”is displayed.

The above-mentioned various lens information is position data (each potentiometer ZP, FP, FP, FP) indicating zoom lens position, focus lens position, extender lens position, and diaphragm position currently set in the lens device 10.
It is calculated based on the position signals obtained by EP and IP, but various control signals (zoom control signals) indicating the target position given to the CPU 14 of the lens device 10 instead of using these position data. , A focus control signal, an extender control signal, and an iris control signal that indicate a target position (hereinafter referred to as control information) are acquired by the CPU 22 of the lens information display device 20, and based on the control information, the same lens as described above is acquired. LCD for information
It may be displayed on the panel 26. In this case, each lens information displayed on the LCD panel 26 indicates a target value finally achieved in the current control signal state.

Further, the types and display forms of the lens information as described above (numerical display and graphic display, metric display and yard display)
Pound display, view angle display at screen size 16: 9, view angle display at screen size 4: 3, etc.) may be switchable.

Next, of the lens information displayed on the LCD panel 26, the processing relating to the display of the subject distance, which is the subject of the present invention, will be described. In order to obtain the subject distance, it is necessary to associate the focus lens position with the subject distance. In the present embodiment, as one method for associating the focus lens position with the subject distance, position data indicating several focus lens positions and measured values of the subject distance corresponding to the focus lens positions at each point are obtained. A method of storing the indicated distance data in advance is adopted. Based on the stored position data of the focus lens position and the distance data of the subject distance, the distance function indicating the relationship between the focus lens position and the subject distance can be obtained, and the focus lens position acquired from the lens device 10 can be obtained. The corresponding subject distance (the subject distance in focus at the focus lens position) can be obtained.

To input the distance data indicating the measured value of the subject distance, first, a predetermined switch (mode switch) of the operation switch section 30 in the lens information display device 20 is operated to set the writing mode. Then, for example, the object to be measured is placed at a certain position, the distance from the lens device 10 to the object to be measured is measured in advance, and the focus lens FL of the lens device 10 is driven to focus on the object to be measured.
Then, an actual measurement value (distance data) of the distance to the measurement object is input by a predetermined switch of the operation switch unit 30.
As a result, the position data indicating the focus lens position acquired from the lens device 10 at that time and the distance data input as the measured value of the distance to the measurement object are associated with each other and written in the EEPROM 32. By repeating such an operation by changing the distance of the object to be measured, a plurality of position data regarding the focus lens position and the distance data corresponding to each position data are associated with each other and the EEPR is obtained.
It is stored in the OM32. In this specification, the data in which the focus lens position and the subject distance are associated with each other is referred to as characteristic data.

When inputting the distance data, the operator focuses the object to be measured while operating the focus lens FL from the near side to the infinity side and inputs the distance data, and the focus lens FL is infinite. While operating from the far side to the near side, focus on the object to be measured and perform both steps of inputting the distance data. The CPU 22 detects the operation direction (movement direction) of the focus lens FL from the change in the focus lens position acquired from the lens device 10, and the focus lens FL until reaching the focus lens position when the distance data is input. It is determined whether the moving direction of is from the near side to the infinity side or from the infinity side to the near side. When the moving direction of the focus lens FL is from the near side to the infinity side, the position data of the focus lens position and the distance data input at that time are stored in the EEPROM.
It is memorized in the 32 [closest → ∞] area. On the other hand, when the moving direction of the focus lens FL is from the infinity side to the close side, the position data of the focus lens position and the distance data input at that time are stored in the EEPROM 32 [∞ → close range].
Store in the area. As a result, FIG. 3 (A), (B)
As shown in, the position data of the focus lens position and the distance data of the subject distance corresponding thereto are EEPRO corresponding to the moving direction of the focus lens FL as characteristic data.
It is categorized and stored in the [closest → ∞] area and the [∞ → closest] area of M32.

On the other hand, when it is desired to display the subject distance corresponding to the currently set focus lens position in the lens device 10 on the LCD panel 26, the display mode is set by a predetermined switch (mode switch) of the operation switch section 30. Set. The CPU 22 sequentially acquires position data indicating the focus lens position from the lens device 10, and detects the operation direction (movement direction) of the focus lens FL from the change in the acquired position data. Then, it is determined whether the moving direction of the focus lens FL is from the near side to the infinity side or from the infinity side to the close side. When the moving direction of the focus lens FL is from the close side to the infinity side, an area in the same moving direction as this, that is, FIG.
As shown in (A), the EEPROM 32 [closest → ∞]
A distance function is obtained using the characteristic data (position data and distance data) stored in the area, and the object distance corresponding to the current focus lens position is calculated using the distance function.

Specifically, first, the [
Nearest → ∞] Of the characteristic data stored in the area,
A plurality of sets close to the current focus lens position are selected and an appropriate function, for example, y is the subject distance and x is the focus lens position,

[0029]

## EQU1 ## y = a / (x-b) + c (1) is calculated. In the case of this example, since it is necessary to obtain three constants a, b, and c, the position data of the focus lens position and the distance data of the subject distance corresponding thereto are set as three sets (x1,
y1), (x2, y2), (x3, y3) are selected,

[0030]

[Mathematical formula-see original document] y1 = a / (x1-b) + c y2 = a / (x2-b) + c y3 = a / (x3-b) + c A three-dimensional simultaneous equation is created and constants a, b, and c are set. Ask. Then, the obtained constants a, b, and c are substituted into the above equation (1), and the position data indicating the current focus lens position is substituted into x of the above equation (1) to calculate the subject distance y.

Similarly, when the moving direction of the focus lens FL is from the infinity side to the close side, the characteristic data ((∞ → close) area of the EEPROM 32 shown in FIG. 3B is stored. The distance function is obtained using the position data and the distance data), and the subject distance corresponding to the current focus lens position is calculated using the distance function. Then, the subject distance calculated as described above is displayed on the LCD.
It is displayed on the panel 26.

As described above, the characteristic data that associates the focus lens position with the subject distance for each moving direction of the focus lens FL is generated in advance and stored in the EEPROM 32, and when the subject distance corresponding to the focus lens position is displayed. Calculates the subject distance by using the characteristic data corresponding to the moving direction of the focus lens FL, and the focus lens FL and the potentiometer FP.
It is possible to eliminate the error caused by mechanical and electrical play between and.

In displaying the object distance, the focus control signal given to the CPU 14 of the lens device 10 as described above is sent to the CPU 22 of the lens information display device 20.
Alternatively, the subject distance corresponding to the target position of the focus lens FL designated by the focus control signal may be obtained and displayed on the LCD panel 26.

Further, instead of the EEPROM 32, other kinds of storage means may be used, and the lens information display device 2
It may be a recording medium that can be attached to and detached from 0.

Next, the CPU 2 of the lens information display device 20
The processing procedure regarding the display of the subject distance in 2 will be described with reference to the flowchart of FIG.

When the power is turned on, the CPU 22 makes necessary initial settings (step S10), and then the lens apparatus 1
A communication connection with 0 is performed (step S12). Next, the current focus lens position (position data) is received from the lens device 10 (step S14). Then, the state of a predetermined switch (mode switch) of the operation switch unit 30 is read (step S16), and it is determined whether or not it is the write mode (step S18). Here, when the determination is YES, the operator focuses on the predetermined measurement object as described above and manually inputs the actual distance measurement value (step S2).
0), the CPU 22 sets the input measured value as distance data (step S22). And the focus lens F
The operation direction (movement direction) of L is detected (step S2
4) It is determined whether the moving direction is from the infinity side to the close side (step S26). If YES is determined, the current focus lens position (position data) and the distance data are stored in the [∞ → near] area of the EEPROM 32 (step S28). On the other hand, when it is determined to be NO, the current focus lens position (position data) and the distance data are stored in the EEPROM 32 [close-up →
∞] Area is stored (step S30). And
The distance data (input measured value) is displayed on the LCD panel 26 (step S48), and the process returns to step S14.

In step S18, NO, that is,
When it is determined that the display mode is set, the operation direction (movement direction) of the focus lens FL is detected (step S40), and it is determined whether or not the movement direction is from the infinity side to the close side (step S40). S42). If YES is determined here, the distance data indicating the object distance is calculated based on the stored data stored in the [∞ → closest] area of the EEPROM 32 and the current focus lens position (position data). (Step S44). On the other hand, N
If it is determined to be O, the [closest to the EEPROM 32 →
∞] Distance data indicating the subject distance is calculated based on the storage data stored in the area and the current focus lens position (position data) (step S46). Then, the calculated distance data is displayed on the LCD panel 26, and the process returns to step S14.

The characteristic data described in the above embodiment may be any data as long as it is data that associates the focus lens position with the subject distance. For example, the relationship between the focus lens position and the subject distance. Or a conversion table that directly converts the focus lens position into a subject distance.

[0039]

As described above, according to the subject distance display device of the present invention, characteristic data that associates the focus lens position with the subject distance is stored for each moving direction of the focus lens, and the movement of the focus lens is performed. Since the subject distance is calculated from the focus lens position based on the characteristic data according to the direction, the problem that the subject distance has an error due to the difference in the moving direction of the focus lens is eliminated.

[Brief description of drawings]

FIG. 1 is a control block diagram showing an overall configuration of a television lens system to which the present invention is applied.

FIG. 2 is a diagram showing an example of lens information displayed on an LCD panel of a subject distance display device.

FIGS. 3A and 3B are explanatory diagrams used for explaining data stored for each moving direction of the focus lens.

FIG. 4 is a flowchart showing a processing procedure regarding display of a subject distance in a CPU of the subject distance display device.

[Explanation of symbols]

10 ... Lens device, 14 ... CPU, 20 ... Lens information display device (subject distance display device), 22 ... CPU, 26 ...
LCD panel, 28 ... Display driver, 30 ... Operation switch section, 32 ... EEPROM

Claims (2)

[Claims] 1. A focus lens of a lens device acquires a focus lens position currently set, or a focus lens position instructed to the lens device by a focus instructing unit as a position to set the focus lens. A focus lens position acquisition unit, a characteristic data storage unit that stores in advance characteristic data that associates a focus lens position with a subject distance for each moving direction of the focus lens, and a focus lens acquired by the focus lens position acquisition unit. A focus lens moving direction detecting means for detecting a moving direction until the focus lens reaches a position, and characteristic data for the moving direction of the focus lens detected by the focus lens moving direction detecting means from the characteristic data storing means. A subject distance calculation unit that obtains and calculates a subject distance corresponding to the focus lens position obtained by the focus lens position obtaining unit based on the obtained characteristic data, and a subject distance calculated by the subject distance calculation unit A subject distance display device, comprising: a display unit for displaying. 2. An actual measurement value receiving means for receiving an actual measurement value of a subject distance corresponding to the focus lens position acquired by the focus lens position acquisition means, and a focus when the actual measurement value is received by the actual measurement value receiving means. The movement direction until the focus lens reaches the lens position is detected by the focus lens movement direction detection means,
A characteristic data generating unit that stores the measured value received by the measured value receiving unit as the characteristic data about the detected moving direction in the storage unit in association with the focus lens position. Item 1
Object distance display device.