JP6695910B2 - Distance detection device and distance detection method - Google Patents

Description

The present invention relates to a distance detection device and a distance detection method .

An image blur prevention device is known that controls the operation of the blur correction unit based on the angular velocity signal from the gyro sensor and the distance to the subject (see Patent Document 1).
[Patent Document 1] Japanese Unexamined Patent Publication No. 2011-23988

  Some image blur prevention devices drive a correction lens according to the output from the gyro sensor and the distance to the subject. However, there is a problem in that the correction lens is driven even though the blur is the panning intentionally performed by the user.

A distance detection device according to the first aspect of the present invention includes a calculation unit that calculates a distance to a detection target by using the time until the projected light is received by the light receiving unit, a sensor that detects blurring, A signal processing unit that calculates a time change of the distance using the distance, a driving unit that drives the shake correction optical system, and a control unit that controls the driving unit based on the output of the sensor and the output of the signal processing unit. ..

A distance detection device according to a second aspect of the present invention includes a calculation unit that calculates a distance to a detection target by using a time until the projected light is received by the light receiving unit, a sensor that detects a blur, Based on the output of the sensor and the distance, it is determined whether collimation is being changed from the detection target to a new detection target and / or whether the detection target is moving, and the drive amount of the shake correction optical system. And a drive unit that drives the shake correction optical system, and a control unit that controls the drive unit based on the output of the determination unit.
A distance detecting method according to a third aspect of the present invention includes a step of calculating a distance to a detection target by using a time until the projected light is received by the light receiving section, a step of detecting blurring, and a distance. A step of calculating a time change of distance, a step of driving a shake correction optical system, a step of detecting a shake, and a step of controlling driving of a shake correction optical system based on a step of calculating a time change of distance And, including.
A distance detecting method according to a fourth aspect of the present invention comprises a step of calculating a distance to a detection target by using a time until the projected light is received by a light receiving section, a step of detecting a blur, and a blurring step. Based on the distance and the step of detecting, the step of determining whether collimation is being changed from a detection target to a new detection target, and / or whether the detection target is moving, and a shake correction optical system. And a step of controlling the driving based on the step of judging.

  The above summary of the invention does not enumerate all the features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

1 is a block diagram of a distance meter 10 according to the present invention. 9 is a block diagram of a portion related to calculation of a shake angular velocity ω inside the drive amount calculation unit 500. FIG. It is a figure explaining the effect of cutoff frequency fc. 7 is a block diagram of a portion related to calculation of a correction lens target position LC inside the drive amount calculation unit 500. FIG. FIG. 6 is a diagram illustrating a relationship between an angular velocity bias amount ωbias and a correction lens target position LC. It is a flowchart explaining operation | movement of the range finder 10. 7 is a flowchart illustrating a moving body flag determination process of rangefinder 10. FIG. It is a figure which shows an example of the ranging sampling result at the time of non-detection of panning. It is a figure which shows an example of the ranging sampling result at the time of panning detection. 6 is a table summarizing combinations of parameters determined by a collimation change determination flag and a moving object flag in the present embodiment. 7 is a flowchart illustrating a shake correction process of the rangefinder 10. FIG. 7 is a flowchart illustrating a shake correction process of the rangefinder 10. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Moreover, not all combinations of the features described in the embodiments are essential to the solving means of the invention.

  FIG. 1 is a block diagram of a distance meter 10 according to this embodiment. The distance measuring device 10 includes a light transmitting unit 100, a light receiving unit 200, a collimation optical system 300, a shake detecting unit 400, a driving amount calculating unit 500, a correcting unit 600, a distance measuring signal processing unit 700, a control unit 800, and operation buttons 900. Equipped with.

The light transmitter 100 emits the measurement light forward. The light transmitting unit 100 includes an objective lens 110, a correction lens 610, an erecting prism 120, and a light emitting unit 130. In the following description, the direction in which the light transmitter 100 emits the measurement light in the distance meter 10, that is, the direction of the arrow of the light beam B _{3 in} the drawing may be referred to as the front.

  The light emitting unit 130 emits a predetermined number of pulsed measurement light beams per unit time. In this case, the light emitting unit 130 emits, for example, hundreds to thousands of pulse lights per second as measurement light. An example of the light emitting unit 130 is a semiconductor laser that oscillates light in the infrared region. Hereinafter, the light emitting unit 130 will be described using an example in which the measurement light in the infrared region is emitted.

The erecting prism 120 reflects the light in the visible light band and transmits the light in the infrared band, and the total reflection that has a high reflectance for the light in the infrared band in addition to the visible light band. And surfaces 124 and 126. The measurement light passes through the dichroic reflection surface 122, is reflected by the total reflection surface 124, and propagates forward in the range finder 10 as a light beam B ₂ . Further, the erecting prism 120 uses the dichroic reflection surface 122, the total reflection surfaces 124, 126 and other reflection surfaces to reverse the inverted mirror image formed by the incident light ray into an erecting erect image. Examples of the erecting prism 120 are a roof prism, a Porro prism, and the like.

  The objective lens 110 is arranged at the front end of the range finder 10, and the end face on the front side faces an object to be the object of distance measurement. In the following description, the target object for distance measurement may be referred to as a target object or a collimation target. The rear end surface of the objective lens 110 faces the front end surface of the erecting prism 120 with the correction lens 610 interposed therebetween.

  The light receiving unit 200 receives the incident light incident from the front, converts the intensity signal of the incident light into an electric signal, and outputs the electric signal. The light receiving unit 200 includes a light receiving lens 210, a bandpass filter 220, and a light receiving element 230, which are optical systems separate from the light transmitting unit 100 and the collimation optical system 300. Thereby, the light receiving unit 200 has an optical axis different from that of the light transmitting unit 100 and the collimation optical system 300.

  A band pass filter 220 and a light receiving element 230 are sequentially arranged behind the light receiving lens 210. The bandpass filter 220 transmits light in a narrow wavelength band including measurement light and blocks or attenuates light in other wavelength bands. Examples of the light receiving element 230 are a photodiode, a phototransistor, and the like having sensitivity to the wavelength band of the measurement light. From the viewpoint of eliminating the influence of background light on the measurement light, the light receiving area of the light receiving element 230 is preferably smaller.

In the light receiving unit 200, the light receiving lens 210 receives the light ray C ₁ reflected or scattered from the object located in front of the range finder 10. The light ray C ₁ is condensed by the light receiving lens 210, propagates backward as a light ray C ₂ , passes through the band-pass filter 220, and then is received by the light receiving element 230.

  The light receiving element 230 converts the received optical signal into an electric signal corresponding to the intensity, amplifies it with an internal amplifier, and then outputs the electric signal to the distance measurement signal processing unit 700.

  The distance measurement signal processing unit 700 calculates the distance to the collimated object based on the timing at which the measurement light is emitted and the timing at which the light receiving unit 200 receives the incident light. The ranging signal processing unit 700 includes a binarization circuit, a sampling circuit, a counter circuit, an oscillator and the like. The electric signal from the light receiving element 230 is converted into a binarized signal by the binarization circuit according to a predetermined threshold value, and is output to the sampling circuit. A sampling clock having a specific frequency is input from the oscillator to the sampling circuit. The count value is input to the sampling circuit from the counter circuit. The sampling circuit performs digital sampling of the input binarized signal and generates a light receiving signal synchronized with the sampling clock. The count value is reset by the control unit 800 at the timing when the pulsed light is emitted from the light emitting unit 130.

  The distance measurement signal processing unit 700 calculates the time difference between the time when the light emitting unit 130 emits the pulsed light and the time when the light receiving element 230 receives the incident light reflected from the object from the count value of the pulse of the light receiving signal. To do.

  The distance measurement signal processing unit 700 similarly sequentially performs the time difference calculation process for each pulsed light of the measurement light. Then, every time the time difference of the pulses in the light receiving signal is calculated, the signal value is integrated into the memory address corresponding to the time difference on the internal memory of the device itself. As a result, a histogram for distance calculation is generated. When the process is completed for the light reception signals corresponding to the predetermined number of pulsed lights, the distance measurement signal processing unit 700 specifies the memory address having the maximum integrated value. The distance measurement signal processing unit 700 determines that the time difference Δt corresponding to the memory address is the time difference between the light transmission and the light reception corresponding to the object.

The distance measurement signal processing unit 700 calculates the distance to the object based on the recognized time difference Δt. Specifically, the distance measurement signal processing unit 700 converts the time difference into a distance by the following formula.
l = c × Δt / 2
Here, 1 is the distance to the object, and c is the speed of light. The ranging signal processing unit 700 sends the information of the calculated distance l to the object to the control unit 800.

  Further, in the present embodiment, the distance measurement signal processing unit 700 repeats the distance measurement for the collimation target and sequentially outputs the distance measurement signals. Here, the distance measurement signal is the time of the distance of the object that is sequentially calculated from the time difference between the time when the light emitting unit 130 emits the pulsed light and the time when the light receiving element 230 receives the incident light reflected from the object. This is a signal indicating a change. The distance measurement signal processing unit 700 outputs the distance measurement signal to the drive amount calculation unit 500 via the control unit 800.

  The control unit 800 comprehensively controls the distance measuring operation in the distance meter 10. The control target of the control unit 800 includes the light transmitting unit 100, the light receiving unit 200, the distance measurement signal processing unit 700, and the like. The control unit 800 indicates the information such as the distance to the target object calculated by the distance measurement signal processing unit 700 to the user by characters or images on the reticle plate 320.

  The collimation optical system 300 collimates an object and forms an optical image of the collimation object. The collimation optical system 300 has a reticle plate 320 and an eyepiece lens 310. The collimating optical system 300 further shares the objective lens 110, the correction lens 610, and the erecting prism 120 with the light transmitting unit 100. As a result, the optical axes of the light transmitting unit 100 and the collimating optical system 300 coincide with each other. The user observes the front through the collimation optical system 300 and sets the collimation with respect to the object.

  The reticle plate 320 is arranged at the focal position of the objective lens 110 of the light transmitting section 100. The front end of the eyepiece lens 310 faces the rear end of the reticle plate 320 inside the rangefinder 10. The reticle plate 320 has a collimation index and a display unit. Examples of the shape of the collimation index are a cross line, a rectangular frame, a circular frame, and the like. The display unit uses a transmissive liquid crystal or the like to show the measurement result of the distance to the object to the user by characters, images, or the like.

Of the light reflected or scattered from the object located in front of the range finder 10, the light ray A ₁ propagating within the range of the view angle of the objective lens 110 is incident on the collimation optical system 300. The light ray A ₁ is condensed as a light ray A ₂ by the objective lens 110 and is emitted as a light ray A _{3 to} the rear of the range finder 10 through the erecting prism 120, the reticle plate 320 and the eyepiece lens 310. As a result, the user observes the erect image of the object through the eyepiece lens 310.

  The collimation index arranged on the reticle plate 320 is superimposed on the image observed by the user through the eyepiece lens 310. The user collimates by orienting the range finder 10 so that the collimation index is superimposed on the image of the object observed through the eyepiece lens 310. In this case, since the apparent optical axes of the light transmitting section 100 and the collimation optical system 300 coincide with each other as described above, the measurement light is irradiated to the position indicated by the collimation index.

  The shake detection unit 400 includes a plurality of angular velocity sensors whose detection directions intersect each other. The plurality of angular velocity sensors are arranged, for example, in a direction that detects pitching and yawing of the range finder 10. Each of the angular velocity sensors detects, when a shake occurs in the range finder 10, detects the shake and outputs a shake signal corresponding to the shake amount including the direction, size, and frequency as information to the drive amount calculation unit 500. To do.

  The drive amount calculation unit 500 calculates the drive amount, which is the displacement amount of the correction lens 610, by periodically referring to the shake signal output from the shake detection unit 400. The drive amount is the amount by which the correction lens 610 is displaced in order to cancel the image shake of the optical image generated in the collimation optical system 300 due to the displacement of the range finder 10. The driving amount includes information on the direction and the size. The drive amount calculation unit 500 outputs a drive signal for driving the correction lens 610 with the drive amount to the drive unit 620.

  In the present embodiment, the drive amount calculation unit 500 drives the correction lens 610 to be driven by the correction unit 600 based on the combination of the output from the distance measurement signal processing unit 700 and the shake detection signal from the shake detection unit 400. The amount is calculated and output to the correction unit 600. In particular, in the present embodiment, a temporal change in the distance calculated by the distance measurement signal processing unit 700 is used as an example of the output from the distance measurement signal processing unit 700.

  The drive unit 620 displaces the correction lens 610 in the direction intersecting the optical axis based on the drive signal received from the drive amount calculation unit 500. For the drive unit 620, for example, a voice coil motor, a piezoelectric motor or the like can be used.

  The position detection unit 630 periodically detects the position of the correction lens 610, and outputs a position signal corresponding to the position to the drive amount calculation unit 500 and the control unit 800. For the position detection unit 630, for example, an optical position detection sensor or the like can be used in addition to a magnetic sensor using a Hall element, an MR element, or the like.

  The drive amount calculation unit 500 feedback-controls the drive amount of the correction lens 610 according to the position signal of the correction lens 610 acquired from the position detection unit 630. As a result, the position of the correction lens 610 can be accurately controlled even when a disturbance such as impact or vibration is applied.

  The correction unit 600 drives the correction lens 610 with a drive amount according to the blur of the optical axis of the collimation optical system 300. The correction unit 600 includes a correction lens 610, a drive unit 620, and a position detection unit 630.

  The correction unit 600 may perform the correction operation at all times, but may perform the correction operation only during the period when the user is using the range finder 10. For example, the user's eyes looking into the eyepiece lens 310 may be detected to determine whether the user is using the rangefinder 10. Then, when it is determined that the user is using the rangefinder 10, the correction unit 600 may be turned on / off. Further, the correction unit 600 may start the operation based on the operation of the operation button 900 by the user. After that, the operation of the correction unit 600 may be stopped when there is no user operation for a predetermined time.

The correction lens 610 is driven by the drive unit 620 in the vicinity of the objective lens 110 to displace the optical paths of the light rays A ₂ and B ₂ . Accordingly, when the range finder 10 is displaced, the correction lens 610 is displaced so as to optically cancel the displacement, whereby the blurring of the image observed by the user can be stopped. Since the correction lens 610 is also used for the light transmitting unit 100, it is possible to continue irradiating the same object with the measurement light even if the range finder 10 is displaced.

  FIG. 2 is a block diagram of a portion related to the calculation of the shake angular velocity ω inside the drive amount calculation unit 500. FIG. 2 shows processing inside the drive amount calculation unit 500. As shown in FIG. 2, the drive amount calculation unit 500 includes an A / D converter 502, a shake angular velocity reference value calculation unit 504, a subtraction unit 506, a collimation change detection unit 508, an fc designation unit 510, a memory 512, and an LPF. The processing unit 514 is included.

  The shake detection unit 400 detects an angular velocity due to the shake of the rangefinder 10 and outputs a shake detection signal, which is a signal corresponding to the detection result, to the drive amount calculation unit 500. The drive amount calculation unit 500 calculates the shake angular velocity ω in order to determine the drive amount of the correction lens 610 from the shake detection signal. Specifically, the drive amount calculation unit 500 converts the shake detection signal into a shake quantization value ω1 that is quantized by the internal A / D converter 502. Next, the shake angular velocity reference value calculation unit 504 performs an LPF calculation from the shake quantized value ω1 to the shake angular velocity reference value ω0 that is a reference of the shake quantized value ω1 using the cutoff frequency fc. Then, the subtraction unit 506 calculates the shake angular velocity ω by subtracting the shake angular velocity reference value ω0 from the shake quantized value ω1. The process of calculating the shake angular velocity ω from the shake quantized value ω1 removes the low frequency component of the shake quantized value ω1 and is substantially an HPF process.

  The collimation change detection unit 508 detects the collimation change based on the magnitude of the shake signal from the shake detection unit. The collimation change detection unit 508 determines from the absolute value of the shake angular velocity ω whether collimation is being changed, and stores a collimation change flag according to the determination result in the memory 512. For the determination, a collimation change start threshold Panωth_s and a collimation change end threshold Panωth_e that are predetermined angular velocity thresholds are used. The collimation change detection unit 508 determines that the collimation change is started when the shake angular velocity ω exceeds Panωth_s. After that, when the shake angular velocity ω falls below Pan ωth_e, it is determined that the collimation change is completed.

  The collimation change flag is set to 1, for example, when it is determined that the collimation is being changed. On the other hand, when it is determined that the collimation is not being changed, it is set to 0. A default value is set for the collimation change flag, and when the rangefinder 10 is activated, for example, 0 is set.

  The memory 512 also stores a moving object flag, which will be described later. The moving body flag is set according to the temporal change in the distance to the object obtained by distance measurement. In the following description, the collimation change flag and the moving body flag may be collectively referred to as flag information. Further, in the memory 512, in addition to the flag information that is sequentially updated, based on the combination of the collimation change flag and the moving body flag, a predetermined cutoff frequency fc, a bias coefficient Kbias described later, a correction range, and the like are stored. Parameter information of is stored. In addition, the memory 512 also stores the default value of the parameter and various threshold information described later.

  The driving amount calculation unit 500 refers to the flag information from the memory 512 and outputs information on a predetermined cutoff frequency fc to the fc designation unit 510. The fc designating section 510 designates the cutoff frequency fc in the processing of the LPF processing section 514. The LPF processing unit 514 calculates the shake angular velocity reference value ω0 from the shake quantization value ω1 using the cutoff frequency fc. A default value is set for the cutoff frequency fc, and the default value is, for example, 0.1 Hz.

  FIG. 3 is a diagram for explaining the effect of the cutoff frequency fc. FIG. 3A shows the shake quantization value ω1 acquired in time series. This indicates that the collimation has been changed from a state where the collimation is relatively stable. FIG. 3B shows the shake angular velocity ω obtained by the HPF process at the cutoff frequency fc = 0.1 Hz for the shake quantization value ω1. Further, FIG. 3C shows the shake angular velocity ω obtained by the HPF process at the cutoff frequency fc = 1.0 Hz for the shake quantization value ω1.

  The range finder 10 calculates the target position of the correction lens 610 for the shake angular velocity ω. In FIG. 3B, since the HPF process is performed at a relatively low frequency of 0.1 Hz, the shake to be corrected still has a relatively large angular velocity component due to panning. On the other hand, in FIG. 3C, since the HPF process is performed at a relatively high frequency of 1.0 Hz, the component of the large angular velocity is removed, and the shake to be corrected is almost the shake. It is the only component that originates.

  Correcting all shakes occurring in the rangefinder 10 may cause inconvenience in use. For example, when the panning is intended by the user, if the operation is performed to correct the shake caused by the panning, the followability to the target object is deteriorated. As a result, there is a possibility that the object cannot be captured in the collimation. Therefore, in the present embodiment, when it is determined that the collimation is being changed, the cutoff frequency fc is set higher than the default value, and a large shake angular velocity is corrected for shake as shown in FIG. Exclude from the target.

  Further, in the present embodiment, the drive amount calculation unit 500 sequentially changes the value of the cutoff frequency fc according to the temporal change of the distance measurement result. Details will be described later.

  FIG. 4 is a block diagram of a portion related to the calculation of the correction lens target position LC inside the drive amount calculation unit 500. As shown in FIG. 4, the drive amount calculation unit 500 includes a memory 512, a subtraction unit 516, an integration unit 518, a multiplication unit 520, a movable range restriction unit 522, and a bias calculation unit 524.

  The driving amount calculation unit 500 calculates the correction lens target value LC from the shake angular velocity ω. Specifically, the drive amount calculation unit 500 first integrates the shake angular velocity ω in the integration unit 518 to calculate the angle. Next, the multiplying unit 520 multiplies the angle by the coefficient KLC to calculate the corrected lens target position LC. The coefficient KLC is a conversion coefficient determined by the focal length of the correction lens 610 and the like.

  The corrective lens target position LC must be within the movable range of the corrective lens 610 in order to perform appropriate shake correction. When the user changes the collimation, the range finder 10 may have a large shake angular velocity. At this time, as a result of performing shake correction for the large shake angular velocity, the correction lens 610 may reach the physical movable range. When the correction lens 610 reaches the physical movable range, further shake correction operation is limited.

  Therefore, the movable range limiting unit 522 converts the correction lens target position LC into the physical movable range by converting the correction lens target position LC so as not to exceed a predetermined movable limit range narrower than the physical movable range. Of the correction lens 610 is prevented. In the present embodiment, the drive amount calculation unit 500 appropriately switches the correction range, which is the movable limit range, according to the flag information stored in the memory 512.

  Further, in the present embodiment, the drive amount calculation unit 500 limits the drive amount of the correction lens 610 by changing the value of the angular velocity bias ωbias that acts to bring the correction lens target position LC closer to the center of the movable range. Here, the angular velocity bias ωbias is a function of the distance from the movable center of the correction lens 610 to the calculated correction lens target position LC. Details will be described later.

  Specifically, a process of subtracting the angular velocity bias amount ωbias from the shake angular velocity ω is performed. The process is performed by the bias calculation unit 524 and the subtraction unit 516. Then, the corrected lens target position LC is recalculated using the angular velocity ω ′ of the difference obtained by the processing. The drive amount calculation unit 500 calculates the drive amount of the correction lens 610 from the correction lens target position LC.

  FIG. 5 is a diagram for explaining the relationship between the angular velocity bias amount ωbias and the correction lens target position LC. The vertical axis represents the angular velocity bias ωbias. The horizontal axis represents the lens target position LC. The correction lens 610 is driven within the correction lens movable range.

When the center of the movable range of the correction lens 610 is set to 0, the angular velocity bias amount ωbias which is the output of the bias calculation unit 524 is calculated by the following equation (1). Here, the coefficient Kbias is a predetermined coefficient. In the following description, Kbias may be referred to as a bias coefficient. The output ω ′ of the subtraction unit 516 is calculated by the following equation (2).
ωbias = Kbias × LC ³ (1)
ω ′ = ω−ωbias (2)

  From the above equation (1), when the correction lens target position LC is close to the center of the movable range of the correction lens 610, the contribution to the angular velocity bias ωbias is small. On the other hand, the correction lens target position LC has a larger contribution to the angular velocity bias amount ωbias as it goes away from the center of the movable range. Therefore, ω ′ obtained by the above equation (2) becomes smaller as the correction lens target position LC is farther from the center of the movable range. Therefore, the correction lens target position LC newly calculated from ω ′ is close to the center of the movable range. That is, the correction lens 610 is returned to the center of the movable range.

  When the angular velocity bias amount ωbias becomes small, shake correction is performed even for a large shake, so that the followability of the optical axis of the collimating optical system 300 to the user's collimation operation deteriorates, but the shake correction effect becomes large. .. On the other hand, when the angular velocity bias amount ωbias becomes large, the shake correction is not performed for a large shake, so that the followability of the optical axis of the collimation optical system 300 to the user's collimation operation is improved, but the shake correction effect is not obtained. descend.

  Further, as can be seen from FIG. 5, when the bias coefficient Kbias is changed in the above equation (1), the angular velocity bias amount ωbias calculated for the same correction lens target position LC changes. In this way, by using the bias coefficient Kbias, the degree of contribution to the calculated correction lens target position LC to the angular velocity bias ωbias can be adjusted. In the present embodiment, the drive amount calculation unit 500 switches the bias coefficient Kbias as appropriate based on the flag information stored in the memory 512.

  FIG. 6 is a flowchart illustrating the operation of the range finder 10. This flow starts when the power of the range finder 10 is turned on by the user pressing the operation button 900. The rangefinder 10 starts a moving body flag determination process (S100) and a shake correction process (S200), which will be described later. Specifically, when the power is turned on by the user, the control unit 800 outputs a drive signal to the drive amount calculation unit 500. When the drive signal is input, the drive amount calculation unit 500 starts the processes of steps S100 and S200.

  When the moving body flag determination process (S100) ends, the process proceeds to step S300, and it is determined whether or not a predetermined time has elapsed since the operation button 900 was last operated by the user (S300). ). The predetermined time is necessary and sufficient time to complete the distance measuring operation. When it is determined that the predetermined time has elapsed (S300: YES), the drive amount calculation unit 500 ends this flow. Specifically, the control unit 800 outputs a drive stop signal to the drive amount calculation unit 500. When the drive stop signal is input, the drive amount calculation unit 500 ends the processing of steps S100 and S200.

  On the other hand, when it is determined that the predetermined time has not elapsed (S300: NO), the drive amount calculation unit 500 continues the processes of step S100 and step S200. Therefore, this flow is always executed when the power of the range finder 10 is ON.

  FIG. 7 is a flowchart illustrating a moving body flag determination process of the range finder 10. As described with reference to FIG. 6, this flow starts when the power of the range finder 10 is turned on by the user pressing the operation button 900.

  The distance measurement signal processing unit 700 executes the distance measurement operation described with reference to FIG. 1 to calculate the distance Dist to the object (S101). Then, the distance measurement signal processing unit 700 outputs the Dist to the drive amount calculation unit 500 via the control unit 800. At this time, the drive amount calculation unit 500 determines whether or not a value is stored in Dist_buf (S102). Here, Dist_buf is a variable created in the memory 512 inside the drive amount calculation unit 500. Note that Dist_buf is initialized by deleting the data stored when the range finder 10 is started.

  When it is determined that the value is not stored in Dist_buf (S102: NO), the drive amount calculation unit 500 stores Dist in Dist_buf (S103), and the process proceeds to step S101. On the other hand, when it is determined that the value is stored in Dist_buf (S102: YES), the driving amount calculation unit 500 sets the distance difference data ΔDist to the absolute value data of the difference between Dist_buf and Dist, that is, the temporal distance. Data of a large amount of change is stored (S104). Here, ΔDist is a variable created in the memory 512 similarly to Dist_buf.

  The driving amount calculation unit 500 stores Dist in Dist_buf (S105). The value stored in Dist_buf is overwritten by the newly stored Dist.

  The drive amount calculation unit 500 determines whether ΔDist is less than a predetermined threshold Target_th1 (S106). When it is determined that ΔDist is less than the predetermined threshold Target_th1 (S106: YES), it is determined that the object is stationary, and 0 is set to the moving object flag stored in the memory 512. (S107). Note that a default value is set for the moving object flag, and for example, 0 is set when the range finder 10 is activated.

  On the other hand, when it is determined that ΔDist is not lower than the predetermined threshold Target_th1 (S106: NO), the drive amount calculation unit 500 determines whether ΔDist is lower than the predetermined threshold Target_th2. (S108).

  When it is determined that ΔDist is less than the predetermined threshold Target_th2 (S108: YES), the drive amount calculation unit 500 determines that the object is moving in the front-rear direction and stores it in the memory 512. 1 is set to the moving object flag that has been set (S109). On the other hand, when it is determined that ΔDist is not less than the predetermined threshold Target_th2 (S108: NO), the drive amount calculation unit 500 determines that the collimation is out of the target and is stored in the memory 512. 2 is set to the moving body flag that is present (S110).

  When the moving body flag is determined and the setting in the memory 512 is completed, this flow ends. Then, the process proceeds to step S300 in the flow of FIG.

  Next, with reference to FIGS. 8 and 9, a method of determining the collimation change flag according to the distance measurement result and the temporal change of the shake angular velocity ω will be described. 8 and 9, the horizontal axis represents time, and the vertical axis represents the amount of change in distance with time and the angular velocity. Further, the moving body flag shown in FIG. 7 will also be described.

  FIG. 8 shows an example where a collimation change is not detected during ranging sampling. FIG. 8A shows a time transition of the temporal change amount ΔDist of the distance of the object calculated by the distance measurement signal processing unit 700. FIG. 8B shows a time transition of the shake angular velocity ω.

  In FIG. 8A, in the period A, ΔDist is between Target_th1 and Target_th2. Therefore, in the period A, the drive amount calculation unit 500 sets 1 to the moving body flag. In the period B, ΔDist exceeds Target_th2. Therefore, the driving amount calculation unit 500 sets 2 in the moving body flag in the period B. Further, in the period C, ΔDist is less than Target_th1. Therefore, in the period C, the drive amount calculation unit 500 sets 0 in the moving body flag.

  In FIG. 8B, there is no period in which the shake angular velocity ω exceeds the collimation change start threshold Panωth_s, and the collimation change flag remains 0.

  In the period A, 0 is set in the collimation change flag and 1 is set in the moving body flag. From FIG. 8A, it can be seen that the distance measurement result is displaced at a constant rate for each time during the period. In addition, FIG. 8B shows that the collimation is not being changed during the period. From the above, the object is moving in the front-rear direction at a constant speed during the period, but the user can determine that the rangefinder 10 is correctly collimated with respect to the object. Therefore, when the collimation change flag is 0 and the moving body flag is 1, the drive amount calculation unit 500 applies default values to all parameters of the cutoff frequency fc, the bias coefficient Kbias, and the correction range. However, since the target object is moving and the collimation may be lost, the collimation change start threshold Panωth_s is lowered. As a result, the drive amount calculation unit 500 can quickly detect the collimation change and change the parameters such as the cutoff frequency fc to the optimum values to ensure the followability to the object.

  In the period B, 0 is set in the collimation change flag and 2 is set in the moving body flag. From FIG. 8A, it can be seen that the distance measurement result fluctuates remarkably at time P during the period. In addition, FIG. 8B shows that the collimation is not being changed during the period. From the above, for example, the user can determine that the distance to the target object cannot be measured although the target object is captured as intended. This is because, for example, since the visual angle in the collimation target is small, it is necessary to stabilize the collimation in a narrow range by correcting shake of lower frequency. Therefore, when the collimation change flag is 0 and the moving body flag is 2, the drive amount calculation unit 500 applies a value lower than 0.1 Hz to the cutoff frequency fc in order to improve the correction effect. Further, a smaller value than the default value is applied to the bias coefficient Kbias, and a wider range than the default value is applied to the correction range of the correction lens 610. Further, for example, when the collimation target starts moving, the collimation change start threshold Panωth_s is lowered so that the collimation target can be collimated quickly. With this, when the collimation change is started corresponding to the movement of the collimation target, the collimation change operation can be quickly detected, and the parameters such as the cutoff frequency fc are changed to the optimum values. The ability to follow objects can be secured quickly.

  In the period C, 0 is set to both the collimation change flag and the moving object flag. It can be seen from FIG. 8A that the target is stationary during the period. In addition, FIG. 8B shows that the collimation is stable during the period. Therefore, when both the collimation change flag and the moving object flag are 0, the drive amount calculation unit 500 applies the default value to any of the parameters.

  FIG. 9 is a diagram showing an example in which a collimation change is detected during ranging sampling. In the description of FIG. 9, FIGS. 9A and 9B show the time changes of ΔDist and ω, respectively, as in FIG. Description that overlaps with FIG. 8 will be omitted.

  In FIG. 9A, ΔDist exceeds Target_th2 in the periods A and C. Therefore, the driving amount calculation unit 500 sets 2 in the moving body flag in the periods A and C. Further, in the period B, ΔDist is between Target_th1 and Target_th2. Therefore, the drive amount calculation unit 500 sets 1 to the moving body flag in the period B. Then, in the periods D, E, and F, ΔDist is lower than Target_th1. Therefore, the drive amount calculation unit 500 sets 0 in the moving body flag in the periods D, E, and F.

  In FIG. 9B, the shake angular velocity ω exceeds the collimation change start threshold Panωth_s until time P. Therefore, until the time P, the drive amount calculation unit 500 sets 1 to the collimation change flag. At time P, the shake angular velocity ω falls below the collimation change end threshold Panωth_e. Therefore, the drive amount calculation unit 500 sets 0 to the collimation change flag.

  In the periods A and C, 1 is set in the collimation change flag and 2 is set in the moving body flag. From FIG. 9A, it can be seen that the distance measurement result fluctuates remarkably with time during the period. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, it can be determined that the user is panning in order to collimate the target object during the period and the target object is not properly captured. Therefore, when the collimation change flag is 1 and the moving body flag is 2, the drive amount calculation unit 500 sets the cutoff frequency fc to 1. Values higher than 0 Hz apply. Further, a larger value than the default value is applied to the bias coefficient Kbias, and a range narrower than the default value is applied to the correction range of the correction lens 610.

  In the period B, 1 is set to both the collimation change flag and the moving object flag. From FIG. 9A, it can be seen that the distance measurement result is displaced at a constant rate for each time during the period. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, the user can determine that the object is panned according to the movement of the object during the period, and that the object is properly captured. Therefore, when the collimation change flag is 1 and the moving body flag is 1, the drive amount calculation unit 500 applies default values to all the parameters.

  In the period D, the collimation change flag is set to 1 and the moving object flag is set to 0. From FIG. 9A, it can be seen that the variation of the distance measurement result for each time period is slight. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, the user can determine that the object is panned according to the movement of the object during the period, and that the object is properly captured. Therefore, when the collimation change flag is 1 and the moving body flag is 0, the drive amount calculation unit 500 applies the default value to any of the parameters.

  As described above, in the present embodiment, the drive amount calculation unit 500 dynamically changes the parameter according to the temporal displacement ΔDist of the object distance and the temporal change of the shake angular velocity ω.

  FIG. 10 is a table summarizing combinations of parameters determined by the collimation change determination flag and the moving object flag in the present embodiment. The data in the table shown in FIG. 10 is stored in the memory 512 in advance. When calculating the driving amount of the correction lens 610, the driving amount calculation unit 500 refers to the flag information and the parameter corresponding to the flag information stored in the memory 512, and sequentially changes the parameters.

  11 and 12 are flow charts for explaining the shake correction processing of the range finder 10. As described with reference to FIG. 6, this flow starts when the power of the range finder 10 is turned on by the user pressing the operation button 900.

  The shake detection unit 400 starts shake detection (S201). Then, as described with reference to FIG. 2, the shake detection unit 400 outputs the shake detection signal to the drive amount calculation unit 500. As described with reference to FIG. 2, the drive amount calculation unit 500 performs quantization processing and HPF processing on the shake detection signal to calculate the shake angular velocity ω (S202).

  The driving amount calculation unit 500 determines whether or not the shake angular velocity ω exceeds a predetermined threshold Panωth_s (S203). When it is determined that the shake angular velocity ω does not exceed the predetermined threshold Panωth_s (S203: NO), the collimation change flag stored in the memory 512 is not set, and the process proceeds to step S208.

  On the other hand, when it is determined that the shake angular velocity ω exceeds the predetermined threshold value Panωth_s (S203: YES), that is, when it is determined that the collimation change has started, the drive amount calculation unit 500 stores the memory 512 in the memory 512. The stored collimation change flag is set to 1 (S204). The drive amount calculation unit 500 determines whether or not the moving body flag stored in the memory 512 is 2 (S205).

  When it is determined that the moving object flag is 2 (S205: YES), the drive amount calculation unit 500 applies a value larger than 1.0 Hz to the cutoff frequency fc used by the LPF processing unit 514. Further, a larger value than usual is applied to the bias coefficient Kbias. Further, as the correction range, a range narrower than usual is applied (S206). On the other hand, when determining that the moving object flag is not 2 (S205: NO), the drive amount calculation unit 500 applies 1.0 Hz to the cutoff frequency fc used by the LPF processing unit 514 (S207).

  Next, the process proceeds to step S208 in FIG. The drive amount calculation unit 500 determines whether or not the collimation change flag stored in the memory 512 is 1 (S208). That is, it is determined whether or not the collimation is being changed in the immediately preceding process. When it is determined that the collimation change flag is not 1 (S208: NO), the process proceeds to step S211.

  On the other hand, when it is determined that the collimation change flag is 1 (S208: YES), it is determined whether the shake angular velocity ω is below a predetermined threshold value Panωth_e (S209). Here, Panωth_e is a threshold value of the angular velocity for determining that the collimation change by the user is completed.

  When it is determined that the shake angular velocity ω is not below Panωth_e (S209: NO), the process proceeds to step S216. On the other hand, when it is determined that the shake angular velocity ω is below Panωth_e (S209: YES), the drive amount calculation unit 500 sets 0 to the collimation change flag stored in the memory 512 (S210). ..

  The drive amount calculation unit 500 determines whether the moving body flag is 2 (S211). When it is determined that the moving object flag is 2 (S211: YES), the drive amount calculation unit 500 applies a value smaller than 0.1 Hz to the cutoff frequency fc used by the LPF processing unit 514. Further, a value smaller than the default value is applied to the bias coefficient Kbias. Then, a wider range than usual is applied as the correction range. Further, a smaller value than usual is applied to Panωth_s (S212).

  When it is determined that the moving body flag is not 2 (S211: NO), the drive amount calculation unit 500 determines whether the moving body flag is 1 (S213). When it is determined that the moving body flag is 1 (S213: YES), the drive amount calculation unit 500 applies 0.1 Hz to the cutoff frequency fc used by the LPF processing unit 514. Also, a default value is applied to the bias coefficient Kbias. Then, a smaller value than usual is applied to Panωth_s (S214). On the other hand, when it is determined that the moving body flag is not 1 (S213: NO), the drive amount calculation unit 500 applies 0.1 Hz to the cutoff frequency fc used by the LPF processing unit 514. Also, a default value is applied to the bias coefficient Kbias. (S215).

  The drive amount calculation unit 500 calculates the correction lens target position LC using the parameters determined by the above processing (S216). Then, the drive amount calculation unit 500 drives the correction lens 610 via the drive unit 620 to perform shake correction (S217).

  When the shake correction process is completed, this flow ends. Then, the process proceeds to step S300 in the flow of FIG.

  In FIG. 1, the objective lens 110, the light receiving lens 210, and the eyepiece lens 310 are represented by a single lens. However, these lenses may include multiple lenses.

  Further, the objective lens 110, the light receiving lens 210, and the eyepiece lens 310 may have variable focal lengths.

  The light emitting unit 130 may emit ultraviolet light instead of emitting infrared light. In this case, the dichroic reflecting surface 122 of the erecting prism 120 according to the first embodiment is also compatible with ultraviolet rays.

  In the above description, the state of the target object (stationary, moving in the front-back direction, etc.) is determined according to the relationship with the thresholds Target_th1 and Target_th2 using the temporal change ΔDist of the distance measurement result. It is also possible to calculate the variation of the distance of the target object, for example, the RMS (root mean square) and the RMS of the time change of the measured distance, and make a determination based on a threshold value set in advance for these.

  Further, in the distance measurement for determining the state of the object, the distance measurement may be performed with a smaller number of pulses than the number used in the normal distance measurement operation. Furthermore, the present invention is not limited to this, and may be applied to a distance measuring method that does not use a histogram.

  The control parameters for the shake correction operation such as the cutoff frequency fc, the bias coefficient Kbias, and the correction range may be adjusted for all, or any one or a combination of two.

  In the above description, the bias coefficient Kbias is used as the control parameter for the shake correction operation, but the angular velocity bias ωbias itself may be changed.

  In the above description, the control parameter is adjusted according to the time change of the measured distance, but the control parameter may be adjusted according to the measured distance to the collimation target. Here, as an example, considering a case where the collimation target is a moving object that moves at a certain speed, the farther the collimation target is, the smaller the angular velocity added to the rangefinder for collimation is. Become. On the other hand, the closer the collimation target is, the greater the angular velocity applied to the rangefinder for collimation. Therefore, for example, the collimation change start threshold is changed according to the distance to the collimation target.

  Specifically, for example, a distance threshold Dth for dividing the distance range into two ranges, a near side and a far side, is set in advance. Then, it is determined whether or not the distance measurement result is larger than the distance threshold Dth. When it is determined that the distance measurement result is larger than the distance threshold Dth, it is determined that the collimation target is in the range on the far side, and the collimation change start threshold is increased. On the other hand, when it is determined that the distance measurement result is smaller than the distance threshold Dth, it is determined that the collimation target is in the near range, and the collimation change start threshold is lowered. By controlling in this way, when the collimation target, which is a moving object, is at a long distance, a relatively small shake can be corrected and stable collimation can be performed. On the other hand, when the collimation target, which is a moving object, is located at a short distance, it is possible to ensure the followability to the collimation target.

  Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The execution order of each process such as operation, procedure, step, and step in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is "preceding" or "prior to" It should be noted that the output of the previous process can be realized in any order unless it is used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described by using “first”, “next”, and the like for convenience, it means that it is essential to carry out in this order. is not.

10 rangefinder, 100 light transmitter, 110 objective lens, 120 erecting prism, 122 dichroic reflection surface, 124, 126 total reflection surface, 130 light emitting unit, 200 light receiving unit, 210 light receiving lens, 220 band pass filter, 230 light receiving Element, 300 collimation optical system, 310 eyepiece, 320 reticle plate, 400 shake detection unit, 500 drive amount calculation unit, 502 A / D converter, 504 shake angular velocity reference value calculation unit, 506 subtraction unit, 508 collimation change Detection unit, 510 fc designation unit, 512 memory, 514 LPF processing unit, 516 subtraction unit, 518 integration unit, 520 multiplication unit, 522 movable range restriction unit, 524 bias calculation unit, 600 correction unit, 610 correction lens, 620 drive unit , 630 position detection unit, 700 distance measurement signal processing unit, 800 control unit, 900 operation buttons

Claims (6)

The emitted light, a calculation unit that calculates the distance to the detection target by using the time until the light receiving unit is received,
A signal processing unit that calculates a time change of distance using the distance calculated by the calculation unit; and a sensor that detects a blur,
A correction optical system driven to correct blur,
A determination result collimation of whether deviates to the detection whether the object is stationary or the detection target based on the time variation of the distance that the signal processing unit has calculated, at least blur the sensor detects It is a predetermined value to be compared with a value corresponding to the detection value of the blur based on the determination result of whether the collimation change operation is performed on the detection target determined using the start of collimation change. Bei example a control unit for changing the predetermined value representing,
The control unit, based on the changed predetermined value, a determination result of whether the detection target is stationary or out of collimation to the detection target, and the collimation change to the detection target Drive the correction optical system based on the determination result of whether or not the operation of
Distance detection device.   The distance detection device according to claim 1, wherein the blur includes a blur caused by collimation change. The control unit is
In the determination result of whether the collimation change operation is performed, it is determined that the collimation change operation is not performed, and whether the detection target is stationary or to the detection target. In the determination result of whether the collimation is off, if it is determined that the detection target is not stationary or the collimation to the detection target is off ,
In the determination result, it is determined that the collimation changing operation is performed, and more than when it is determined that the detection target is not stationary or the collimation to the detection target is out of alignment .
The distance detection device according to claim 1, wherein the distance detection device is controlled such that a predetermined value indicating the start of the collimation change becomes small.   The distance detection device according to claim 1, wherein the sensor includes an angular velocity sensor.   An optical instrument comprising the distance detection device according to claim 1. A calculation step of calculating the distance to the detection target by using the time until the projected light is received by the light receiving unit,
A signal processing step of calculating a time change of the distance using the distance calculated in the calculation step;
A detection process for detecting blurring,
A driving step of driving the correction optical system for correcting the blur,
Based on the time change of the distance calculated in the signal processing step, whether or not the detection target is stationary or out of sight to the detection target, and at least the blur detected in the detection step. Based on the determination result of whether the collimation change operation is performed on the detection target is determined by using a predetermined value to be compared with the value corresponding to the blur detection value, and a control step of changing the predetermined value representing the start,
Only including,
In the driving step, a determination result of whether or not the detection target is stationary or out of collimation to the detection target based on the changed two predetermined values, and the collimation to the detection target Driving the correction optical system based on the determination result of whether or not the change operation is performed,
Distance detection method.

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