JP3140454B2 - Moving object ranging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a moving object distance measuring device, and more particularly to, for example, an automatic focus photographing device of a camera for driving a photographing lens to a focus position based on a focus detection output. The present invention relates to a moving object distance measuring apparatus for predicting a position of a subject after a predetermined time in order to prevent defocus due to movement of the subject in the optical axis direction of the taking lens.

[Prior Art] Conventionally, when an image of a subject moving in the direction of the optical axis of a photographing lens is to be photographed, there is a disadvantage that the subject is shifted during the release time lag, resulting in defocus.

In order to prevent this defocus, for example, Japanese Patent Application Laid-Open No. 63-159817 discloses a photographic lens in which a distance measurement operation is performed a plurality of times in response to a first release signal, and a position of a subject at the start of exposure is predicted. Is disclosed. In fields other than cameras, for example,
As disclosed in Japanese Patent Application Laid-Open No. 62-232571, a method has been proposed in which infrared rays are projected onto an object to be measured and a moving speed of the object to be measured is detected based on a reflected signal.

Here, a conventional speed detecting device will be described with reference to the above-mentioned Japanese Patent Application Laid-Open No. 63-159817.

In FIG. 8, reference numeral 1 denotes a subject, and reference numerals 2 to 4 denote a distance measuring optical system, a light emitting element drive circuit, and a distance calculation circuit, respectively, which constitute a distance measuring device.

That is, when the infrared light emitting diode (IRED) 2a included in the distance measuring optical system 2 is driven by the light emitting element driving circuit 3, the light from the IRED 2a is projected on the subject 1 via the light projecting lens 2b. You. The light projected on the subject 1 is reflected there, then condensed by a light receiving lens 2c, and is imaged on a light position detecting element (PSD) 2d. Then, the signal currents I ₁ and I according to the incident position of the reflected signal light are output from the PSD 2d.
₂ is output. The distance to the subject 1 is obtained by processing the signal currents I ₁ and I ₂ by the distance calculation circuit 4.

In the speed detecting device, the operation is repeated at the time interval of the distance measuring operation as described above according to the timing circuit 5. Then, after each distance measurement result is stored in the distance data storage circuit 6, the movement speed is detected by calculating how much the position of the subject 1 has been displaced within a predetermined time.

In addition, this speed detecting device includes a dedicated function determining circuit 7 including an order determining circuit 7a, a linear function determining circuit 7b, and a quadratic function determining circuit 7c in order to determine a speed change. It includes a distance prediction calculation circuit 8 for predicting the subject distance at the time (at the start of exposure), and a control circuit 9 for controlling them.

[Problem to be Solved by the Invention] In an actual camera, when a distance to a subject is l, focusing is performed by a reciprocal of l, that is, a signal proportional to 1 / l.

Further, the output result of a generally used triangulation distance measuring device is in a form proportional to 1 / l.

Therefore, when the subject is not a moving object, that is, when the subject is in a stationary state (still subject), the lens extension amount for focusing and the distance measurement result 1 / l are 1
It was possible to convert easily with the following relationship.

However, in the above-described concept of speed detection, the subject distance at the predicted timing t is obtained from the distance measurement results 1 / l ₁ and 1 / l ₂ and the speed detection result v when the subject is measured.
When seeking l _3, it is necessary to next operation.

That is, the distance measurement result is used to calculate the speed v (= (l ₂ −l ₁ ) / t).
1 / l ₁ and 1 / l ₂ are transformed into l ₁ and l ₂ by reciprocal operation.

The object distance l ₃ (= l ₁ −v × t) is extended A (=
Before conversion into α · (1 / l ₃ )), this is again transformed into 1 / l ₃ by reciprocal operation.

As described above, when the subject is a moving object, a complicated calculation process is required to obtain the predicted position. The time required for these calculations cannot be neglected in view of the calculation capabilities of the CPU and the like, and was not acceptable as a distance measuring device.

As described above, in the related art, there is a disadvantage that the calculation for obtaining the predicted position is complicated, and a time lag due to the calculation is large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a moving object distance measuring apparatus that can perform high-speed processing with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, a moving object distance measuring apparatus according to claim 1 of the present invention provides a moving object distance measuring apparatus that outputs an output proportional to the reciprocal of the distance to a subject. Distance means, displacement amount calculating means for outputting a displacement amount represented by a reciprocal of the distance of the subject from a difference between outputs of the distance measuring means at different timings,
A displacement rate calculating means for calculating a displacement rate of the subject from the displacement amount and the time of the timing and outputting a displacement rate signal; and photographing the subject after a predetermined time based on the distance signal and the displacement rate signal. Prediction means for predicting a position corresponding to the in-focus position of the lens.

The moving object ranging device according to claim 2 of the present invention further includes a storage unit that stores in advance a correction amount corresponding to the displacement rate and the position of the subject after a predetermined time with respect to the distance, The prediction unit reads the correction amount from the storage unit based on the displacement rate and the distance,
The prediction is performed using this correction amount.

In the moving object distance measuring apparatus according to a third aspect of the present invention, the moving object distance measuring apparatus further includes integrating means capable of performing positive integration and negative integration of the distance signal, and the displacement rate calculating means performs the positive integration and the negative integration by the integrating means. The displacement rate is obtained by negative integration.

[Operation] In the moving object distance measuring apparatus according to claim 1 of the present invention, an output proportional to the reciprocal of the distance to the subject is output by the distance measuring means, and the output is obtained from a difference between outputs of the distance measuring means at different timings. The displacement amount represented by the reciprocal of the subject distance is output from the displacement amount calculating means. The displacement rate calculating means calculates a displacement rate of the subject from the displacement amount and the time of the timing, and outputs a displacement rate signal. Then, based on the distance signal and the displacement rate signal, a position corresponding to a focus position of the photographing lens with respect to the subject after a predetermined time is predicted by the prediction unit.

Further, the moving object distance measuring apparatus according to claim 2 of the present invention further includes a storage unit, and stores in advance a correction amount corresponding to the displacement rate and the position of the subject with respect to the distance after a predetermined time, The prediction unit reads the correction amount from the storage unit based on the displacement rate and the distance, and performs the prediction using the correction amount.

A moving object distance measuring apparatus according to a third aspect of the present invention has an integrating means for enabling a positive integration and a negative integration of the distance signal, and the displacement rate calculating means makes the positive integration and the negative integration by the integrating means. Is used to determine the displacement rate.

According to the present invention, since the position of the subject after a predetermined time can be predicted without performing a complicated operation such as a reciprocal operation by the above-described means, effective processing can be performed in a short time. is there.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a moving object distance measuring apparatus according to the present invention.

That is, the CPU 11 controls the entire device, and the CPU 11 is connected to the timing control circuit 13, the 1 / l arithmetic circuit 14, and the Δ1 / l arithmetic circuit 15.

The timing control circuit 13 controls the drive timing of the 1 / l arithmetic circuit 14, the Δ1 / l arithmetic circuit 15, and the driver 16 respectively.

The driver 16 drives an infrared light emitting diode (IRED) 12a included in the distance measuring optical system 12, and controls the IRED 12a at the first or second distance measuring timing under the control of the timing control circuit 13. It is designed to emit light.

The distance measuring optical system 12 condenses the IRED 12a, the light projecting lens 12b that projects light (infrared light signal) from the IRED 12a toward the subject 10, and the reflected light from the subject 10. It comprises a light receiving lens 12c and a light position detecting element (PSD) 12d that generates signal currents I ₁ and I ₂ according to the incident position of the reflected signal light condensed by the light receiving lens 12c.

The 1 / l arithmetic circuit 14 is proportional to the reciprocal of the distance 1 to the subject 10 by extracting the signal light component from the output signal of the PSD 12d supplied via the amplifier circuit 17 and calculating the signal light component in an analog manner. A distance signal (distance measurement result) is obtained. In this case, the PSD 12d outputs a signal that depends on the reciprocal of the subject distance 1 based on the light emission of the IRED 12a. Then, after amplifying this signal with the amplifier circuit 17,
Under the control of the timing control circuit 13, the distance measurement calculation is performed at a plurality of different timings.

The Δ1 / l calculation circuit 15 calculates the temporal displacement rate of the subject 10 from the output of the 1 / l calculation circuit 14. The temporal displacement rate obtained here is based on the time t _{0 at} which the subject 10 is displaced at different timings, for example, between the first distance measurement (1 / l ₁ ) and the second distance measurement (1 / l ₂ ). , Δ1 / l = (1 / l ₂ −1 / l ₁ ) / t ₀ (1)

This Δ1 / l is not obtained as v = (l ₂ −l ₁ ) / t (2) like the velocity v (where l ₁ and l ₂ are object distances, and t is l ₁ from the time required to change to l _2.), wherein is referred to as a dare time displacement rate to distinguish the velocity v.

The CPU 11 controls the drive timing of the timing control circuit 13, and controls the output of the 1 / l arithmetic circuit 14 and Δ1
Based on the output of the / l arithmetic circuit 15, moving object distance measurement, that is, the position of the subject 10 after a predetermined time is predicted. Also,
The CPU 11 has a table (storage means) constituted by a ROM or the like, and refers to this table based on the two output results to derive the correction amount up to the predicted position. I have.

The above-described correction amount refers to, for example, a case where the camera attempts to drive the lens to the predicted focus position lx.
The amount (Δ1 / lx) indicates how much correction should be applied to the distance measurement result 1 / l ₁ for the 10 initial positions.

FIG. 2 shows an example of the operation related to the above-mentioned moving object ranging.

First, the reciprocal 1 / l ₁ of the distance 1 at the initial position of the subject 10 is obtained in the 1 / l arithmetic circuit 14 by the first distance measurement. In this case, if the distance measurement time is long, the subject 10 moves during that time, so that the measurement is performed in a short time (first distance measurement timing).

Next, a second ranging is performed at a second ranging timing having a longer ranging time than the above-described first ranging timing,
The reciprocal 1 / l ₂ of the subject distance 1 at a position different from the above is obtained by the 1 / l arithmetic circuit 14.

Next, the Δ1 / l calculation circuit 15 calculates the temporal displacement Δ1 / l of the subject 10 using the result 1 / l ₂ of the second distance measurement. In this embodiment, the result of the second ranging is 1 / l ₂
Is obtained as an integrated output (moving object detection signal) V _OUT by integration in the forward and reverse directions.

In this case, integration is performed in the positive direction until the seventh light emission of the IRED 12a, and integration in the negative (reverse) direction is performed after the eighth light emission. Since the time difference t ₀ between the distance timing and the eighth distance measurement timing is equal to the time difference between the second and ninth times, the third and tenth times,..., The moving object detection signal V _OUT is t _0. When the distance measurement result 1 / l changes due to the time difference, the output depends on the temporal displacement rate Δ1 / l.

In the CPU 11, the first distance measurement result 1 is obtained at the timing (a).
By reading / l ₁ as the distance signal V _{1 / l} and reading the moving object detection signal V _OUT (temporal displacement Δ1 / l) at the timing (b), the correction calculation described later at the timing (c) Is to be executed. That is, the distance measurement result 1 / l ₁ is corrected based on the temporal displacement rate Δ1 / l, and the reciprocal 1 / l of the distance l of the subject 10 at a predetermined timing is obtained.
lx, that is, the position of the subject 10 after a predetermined time is obtained.

In general, in a camera or the like, since the extension amount of the focusing lens has a linear relationship with the distance measurement result 1 / l, it is easy to convert the value of 1 / lx obtained here to the extension amount.

 Here, the above-described correction calculation will be described.

When the temporal displacement amount Δ1 / l of the subject 10 is obtained by the Δ1 / l arithmetic circuit 15, it is expressed by the above equation (1).

On the other hand, it is assumed that the distance l of the subject 10 changes as follows: l = l ₁ −vt (3) (where t is time,
l ₁ is the initial position of the subject 10. ). Then, the speed v at that time becomes the same as the above equation (2).

In order to obtain this velocity v, when the above equation (1) is modified, (Δ1 / l) · t ₀ = 1 / l ₂ −1 / l ₁ = 1 / (l ₁ −vt ₀ ) −1 / l ₁ ∴ 1 / (l ₁ −vt ₀ ) = (Δ1 / l) · t ₀ + 1 / l ₁ ∴ l ₁ −vt ₀ = 1 / ｛(Δ1 / l) · t ₀ + 1 / l ₁ ｖ v = [l ₁ −1 / ｛(Δ1 / l) · t ₀ + 1 / l ₁ }] / t ₀ (4)

Further, the distance to the subject 10 at a predetermined timing t ₂
Assuming l ₃ (predicted focus position lx), the above (3)
Is represented by l ₃ = l ₁ −v · t ₂ (5).

Now, for example, when a correction amount for focusing on this distance l ₃ is obtained, if correction is performed on the distance measurement result 1 / l ₁ obtained by the 1 / l arithmetic circuit 14, the correction amount Δ1 /
lx is defined by Δ1 / lx = 1 / l ₃ −1 / l ₁ (6).

Then, this equation (6) is converted into the above equations (4) and (5).
By substituting the expression, Becomes

In this case, the times t ₀ and t ₂ can be treated as constants,
Thus the correction amount .DELTA.1 / lx can be determined by the initial position l ₁ and the temporal displacement .DELTA.1 / l of an object 10. However, if this correction amount Δ1 / lx is to be obtained by the strict correction calculation as described above, the time lag due to the calculation and the CPU 1
The number of ROM bytes required for 1 operation software cannot be ignored.

Therefore, in the present invention, the correction amount Δ1 / lx can be obtained by a simple method by referring to a table based on the distance measurement result 1 / l and the temporal displacement rate Δ1 / l of the subject 10. I can do it.

 Next, an embodiment of the present invention will be further described.

FIG. 3 shows details of the configuration of the optical system 12 for distance measurement.

The distance measuring optical system 12 constitutes a known one-point distance measuring device, and is a so-called active method of projecting AF light onto the subject 10.

Now, when the IRED 12a emits light, the light becomes AF light and is projected on the subject 10 via the light projecting lens 12b. Then, the AF light is reflected by the subject 10, and is condensed via the light receiving lens 12c to be formed as an image on the PSD 12d.

In this case, the incident position x of the reflected light is represented as a function of the subject distance 1 as shown in the following equation, based on the principle of triangulation.

Here, S is the distance between the principal points (base line length) between the light projecting lens 12b and the light receiving lens 12c, f is the focal length of the light receiving lens 12c, and the PSD 12d is arranged at this position. .

The PSD 12d outputs two signal currents I ₁ and I _{2 that} are functions of the incident position x. The total signal photocurrent and Ip _0, PSD12d
Assuming that the length of tp is tp, l can be expressed as in the following equation.

Here, a is the emission center of the IRED 12a and the projection lens 12b.
When a line parallel to the line connecting to the principal point is extended from the principal point of the light receiving lens 12c, the point that crosses the PSD 12d
Is the length up to the end on the IRED12a side.

As described above, when the distance measurement result is calculated using I ₁ / (I ₁ + I ₂ ), the value is an output in a form proportional to the reciprocal 1 / l of the distance 1 as described above.

FIG. 4 shows the distance signal V from the output signals I ₁ and I ₂ of the PSD 12d.
₂ shows a specific circuit configuration for obtaining _{1 / l} and a moving object detection signal _VOUT .

In FIG. 4, reference numerals 21 and 22 denote output amplifiers I ₁ and I ₂ of the PSD 12 d generated in response to the light emission of the IRED 12 a with low input impedance and amplify them.
Is a compression diode for compressing only the signal light components of the amplified currents I ₁ and I ₂ .

Reference numerals 25 and 26 denote buffers for guiding the compression voltage of the compression diodes 23 and 24 to a differential operation circuit 30 including NPN transistors 27 and 28 and a current source 29.

Here, the operation of the differential operation circuit 30 will be described using symbols in the drawing. Holds. Is is the transistor 27,2
8 and a reverse saturation current of the diode 23, 24, V _T is the thermal voltage.

Further, the current Ia and the current Ib are calculated from the above equations (12), (13), and (14) from the relationship of Ia + Ib = I ₀₁ (14). The relationship holds.

Therefore, from the above equations (11) and (15), And a signal current Ia proportional to the reciprocal of the subject distance 1 is obtained.

Further, since the differential operation circuit 34 including the transistors 31 and 32 and the current source 33 satisfies the same relationship,
The current Ia flowing through the collector of the transistor 31 is as described in (16)
It becomes the same as the formula.

The current source 33 is connected to the IRED 12a by the timing signal TIM.
Is turned on only when the light is emitted. Therefore, the signal current Ia represented by the above equation (16) is sequentially integrated by the integrating capacitor 35, and the above-mentioned distance measurement result 1 / l ₁ is obtained from this output (distance signal V _{1 / l} ).

Note that H / L in the first distance measurement shown in FIG.
Specifically, the state of H means the light emission of the IRED 12a and the ON operation of the current source 33.

On the other hand, the calculation of the temporal displacement rate Δ1 / l of the subject 10 is performed by turning on / off the switches SW1 and SW2, and is taken out as the voltage output of the integrating capacitor 36 (moving object detection signal V _OUT ).

That is, the switch SW1 is turned on in synchronization with the light emission of the IRED 12a at the first to seventh distance measurement timings of the second distance measurement shown in FIG. At this time, PNP
By the function of the current mirror circuit 39 including the transistors 37 and 38, the signal current Ia flows into the integration capacitor. Therefore, its voltage output is
It is expressed as a positive integral as shown in the figure.

The switch SW2 is set to the above-mentioned IR at the eighth to fourteenth distance measurement timings of the second distance measurement shown in FIG.
It is turned on in synchronization with the emission of the ED 12a. At this time, since the signal current Ia flows out of the integration capacitor 37, its voltage output is expressed as an integration in the negative direction (reverse direction) as shown in FIG.

Each output (V _{1 / l} , V _OUT ) is subjected to A / D conversion and taken in by the operation of the CPU 11, and is subjected to a correction operation. That is, the correction amount Δ1 / lx is obtained as described above, and is added to the result 1 / l ₁ of the first distance measurement as shown in the above equation (6), whereby the distance of the subject 10 at the predetermined timing is obtained. The reciprocal 1 / lx of 1 is obtained.

The reset circuit 40 is for initializing the two integration capacitors 35 and 36 described above, and the operation of the circuit 40 is released at the start of the integration operation.

Next, a method of obtaining a correction amount by referring to a table will be described.

FIG. 5 is a diagram showing the equation (7).

That is, the vertical axis is the correction amount Δ1 / lx (m), the horizontal axis is the result of the first distance measurement 1 / l ₁ (m), and the temporal displacement rates Δ1 / l are 0.1, 0.2, 0.3, 0.4, The case of 0.5 is shown as an example.

As is clear from this figure, the temporal displacement rate Δ
1 / l is an approximately equally-spaced curve. This is C
The correction amount Δ1 is stored in the internal ROM of the PU 11 based on the distance measurement result 1 / l ₁ (distance signal V _{1 / l} ) and the temporal displacement rate Δ1 / l (moving object detection signal V _OUT ).
If a table for obtaining / lx is provided, even if the temporal displacement rate Δ1 / l has a value to the second decimal place, for example, 0.15, the correction amount Δ1 / lx at that time Indicates that it can be easily obtained by interpolation calculation.

Therefore, in this case, for example,
As shown in the figure, the correction amount Δ is calculated from the speed v and the subject distance l _1.
The accuracy of the interpolation operation is superior to the case where 1 / lx is obtained. That is, if the speed v is given a linear numerical value, the accuracy of the interpolation operation does not deteriorate as the speed v decreases. .

FIG. 7 shows an example of a table for obtaining the correction amount Δ1 / lx from the distance measurement result 1 / l ₁ and the temporal displacement rate Δ1 / l.

Here, when the correction amount becomes too large, for example, when it becomes 1.0 (1 / m) or more, a warning operation is performed without performing the above-described correction calculation. As the warning operation, for example, in a camera, an LED in a finder may be blinked or a sounding element may be driven so that the user can recognize the warning operation. Further, processing such as prohibiting release may be performed.

As is clear from FIG. 5, the correction amount Δ1 / lx does not depend much on the distance measurement result 1 / l ₁ in an area where the distance measurement result 1 / l ₁ is large. Therefore, when the distance measurement result 1 / l ₁ is, for example, equal to or greater than 1 / 1.25 (m), the correction amount Δ1 / lx is set to the same data.

Further, when the temporal displacement rate Δ1 / l is 0.1 or less, or when the distance measurement result 1 / l ₁ is 1/5 (m) or less, the correction calculation (correction amount Δ1 / lx = 0) is not particularly performed. And

If the distance measurement result 1 / l ₁ is 1 / 1.67 (m) and the temporal displacement rate Δ1 / l is not on the table like 0.25, the CPU 11
, The temporal displacement rate Δ1 / l = 0.2 and the temporal displacement rate Δ1 /
Interpolation calculation is performed from the data of l = 0.3. That is, As described above, the position of the subject after a predetermined time can be predicted without performing a complicated operation such as a reciprocal operation.

That is, a distance signal depending on the initial position of the subject is obtained in the first distance measurement, a temporal displacement rate is obtained in the second distance measurement, and a table is referred to based on these two outputs to obtain the predicted position. The correction amount from the initial position is obtained. This eliminates the need for cumbersome reciprocal operations and the like, making it possible to minimize the time lag involved in the operations. Therefore, effective processing can be performed in a short time with a simple configuration, and high-speed and high-precision moving object distance measurement can be realized.

In particular, in cameras and the like, the amount of extension of the focusing lens is approximately proportional to the reciprocal (1 / lx) of the distance at the predicted focus position.
By extending the lens in accordance with the reciprocal 1 / lx derived based on the correction amount obtained from the table, it is possible to easily take a focused photograph of a moving subject (moving object). Things.

In the above embodiment, the first distance measurement and the second distance measurement are separately shown. However, the present invention is not limited to this. For example, a part of the distance measurement timing in a certain distance measurement operation is used for the first distance measurement. A part or the whole may be used for the second distance measurement.

Of course, various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above in detail, according to the present invention, more effective processing can be performed, so that a moving object distance measuring apparatus that can perform high-speed processing with a simple configuration can be provided.

[Brief description of the drawings]

1 to 7 show an embodiment of the present invention. FIG. 1 is a block diagram schematically showing the configuration of a moving object distance measuring apparatus, and FIG. 2 is an outline of an operation relating to moving object distance measuring. FIG. 3 is a configuration diagram showing details of a distance measuring optical system, FIG. 4 is a diagram showing a specific circuit configuration example, and FIG. 5 is a diagram showing a distance measurement result and a correction amount. FIG. 6 is a diagram schematically illustrating the relationship between the temporal displacement rate of the subject, FIG. 6 is a diagram schematically illustrating the relationship between the subject distance and the speed with respect to the correction amount, and FIG. 7 is a diagram illustrating the relationship between the distance measurement result and the temporal displacement rate. FIG. 8 is a diagram showing an example of a table for obtaining a correction amount, and FIG. 8 is a block diagram of a speed detecting device shown to explain a conventional technique and its problems. 10… Subject, 11… CPU, 12… Distance measuring optical system, 12a…
… IRED, 12d …… PSD, 13 …… Timing control circuit, 14…
… 1 / l arithmetic circuit, 15… Δ1 / l arithmetic circuit, 16… driver, 23, 24… compression diode, 29, 33… current source, 30, 3
4 …… Differential operation circuit, 35,36 …… Integration capacitor, 39 ……
Current mirror circuit, 40 ... Reset circuit, SW1, SW2 ...
…switch.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01C 3/00-3/32 G01P 3/36 G02B 7/28-7/32 G03B 13/36

Claims (3)

(57) [Claims] 1. A distance measuring means for outputting an output proportional to a reciprocal of a distance to a subject, and a displacement rate represented by a reciprocal of the distance to the subject from a difference between outputs of the distance measuring means at different timings. A displacement rate calculating means for calculating a displacement rate of the subject from the displacement rate and the time of the timing, and outputting a displacement rate signal; a predetermined value based on the distance signal and the displacement rate signal; A moving object distance measuring device, comprising: a prediction unit that predicts a position corresponding to a focus position of the photographing lens with respect to the subject after a time. 2. The storage device according to claim 1, further comprising a storage unit configured to previously store a correction amount corresponding to the position of the subject after a predetermined time with respect to the displacement ratio and the distance. 2. The moving object distance measuring apparatus according to claim 1, wherein the correction amount is read from the storage unit, and the prediction is performed using the correction amount. 3. The apparatus according to claim 1, further comprising an integrating means capable of performing positive integration and negative integration of the distance signal, wherein the displacement rate calculating means obtains the displacement rate by the positive integration and the negative integration by the integrating means. The moving object ranging device according to claim 1.