JP2003043340A - Rangefinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a range finder with a little ranging errors caused by an assembly errors of an AF sensor and a light-receiving lens, in which range finding is carried out without having to use a special sensor. SOLUTION: The range finder consists of light-receiving lenses 11a and 11b, a pair of line sensors 12a and 12b, an integral control circuit 13, an A/D conversion circuit 14, and a CPU 15. Then, read subject image data are divided into a plurality of areas, and first calculation which calculates data corresponding to a subject distance for each of a plurality of the areas is carried out by the CPU 15. Furthermore, based on the data obtained by the first calculation, a plurality of areas adjoining each other in the prescribed range are selected from a plurality of the areas, and the subject image data in a plurality of the selected areas are used to carry out a second calculation. Final subject distance data are calculated, based on the result of the second calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive distance measuring device using a line sensor or area sensor.

[0002]

2. Description of the Related Art Conventionally, a light receiving portion of an external light passive range finder is composed of a pair of light receiving lenses and a pair of line sensors. In this light receiving section, it is ideal that a line _BL connecting the optical axes of the pair of light receiving lenses and a line B _S connecting the centers of the pair of line sensors are parallel to each other after assembling.

However, in reality, the assembly error and
As shown in FIG. 16, due to product variations, etc., B_L
And B_SAre not parallel and have an angle θ. The figure
Among them, L1 and L2 represent the subject image with the line sensors S1 and S.
2 is a light receiving lens for forming an image on S2,
2 is a subject image formed by the light receiving lenses L1 and L2
A line sensor that photoelectrically converts and outputs as sensor data
It's a service. In addition, as described above, B_LIs a pair of received light
A line connecting the optical axes of the lenses L1 and L2, B_SIs a pair of lines
It is a line connecting the centers of the sensors S1 and S2, and θ is a pair of
A line B connecting the optical axes of the light receiving lenses L1 and L2_LAnd a pair of la
Line B connecting the centers of in-sensors S1 and S2 _SAngle formed by
Is.

As described above, in the case of the distance measuring device assembled with B _L and B _S having the angle θ, depending on the angle of the pattern P of the subject, as shown in FIGS. , The distances between the images formed on the pair of line sensors are changed as shown by D1 to D3 shown in FIGS. 17D to 17F even if the subjects are present at the same distance. It becomes a distance measurement error. In the figure, P1 is a subject pattern imaged on the line sensor S1 by the light receiving lens L1, and P2 is a subject pattern imaged on the line sensor S2 by the light receiving lens L2. Further, D1, D2, and D3 are the image distances when measuring the oblique pattern upward subject to the right,
An image interval when measuring a vertical pattern subject, and an image interval when measuring a diagonally upward diagonal pattern subject.

In order to solve such a problem, for example, a technique disclosed in Japanese Patent Laid-Open No. 2000-206403 is known. As shown in FIG. 10, this is one line sensor S of the pair of line sensors.
The line sensor S3 is arranged at a position shifted by h in the direction perpendicular to the base line length direction on the 2nd side, and the line sensor S2 and the pattern P2 of the subject formed on the line sensor S3 form the difference X between the positions of the subject pattern P. Find the angle φ
Is a technique for correcting the image interval D by the angle θ formed between B _L and B _S. In the figure, h is the line sensors S2, S
3 intervals.

[0006]

However, in the case of the method disclosed in Japanese Unexamined Patent Application Publication No. 2000-206403 mentioned above, the third line sensor is used in addition to the pair of line sensors used for normal passive distance measurement. Since the line sensor is required, the chip area of the AF sensor is increased and the cost is increased.

When the subject pattern is a simple linear pattern, the above-mentioned correction is effective, but a plurality of patterns are mixed or arranged in the direction perpendicular to the base line length direction. If the subject pattern is imaged on only one of the two line sensors, correct correction cannot be performed, and in the worst case, the distance measurement error may be larger than that before correction. is there.

Therefore, an object of the present invention is to provide a distance measuring device having a small distance measuring error caused by an assembly error between the AF sensor and the light receiving lens without using a special sensor.

[0009]

That is, according to the present invention, a light-receiving lens for forming a pair of subject images on a pair of line sensors, and a pair of subject images formed by the light-receiving lens according to the light intensity. A pair of line sensors for converting the electric signals into electric signals, a control means for controlling the operation of the pair of line sensors, a reading means for reading subject image data output from the pair of line sensors, and a reading means for reading the subject image data. In the distance measuring device including a calculation means for calculating data according to the subject distance based on the subject image data, the calculation means divides the read subject image data into a plurality of areas, The first calculation for calculating the data corresponding to the subject distance is performed for each of the plurality of areas, and based on the data obtained by the first calculation, a plurality of adjacent areas within a predetermined range from the plurality of areas are used. Select, performs the second operation using the object image data in a plurality of selected areas, characterized by calculating the final subject distance data from the results of this second operation.

Further, according to the present invention, a light receiving lens for forming a pair of object images on a pair of line sensors, and a pair of object images formed by the light receiving lens are converted into electric signals according to light intensity. A pair of area sensors, control means for controlling the operation of the pair of area sensors, reading means for reading subject image data output from the pair of area sensors, and subject image data read by the reading means. In the distance measuring device including a calculation means for calculating data according to the subject distance, the calculation means divides the read subject image data into a plurality of areas, and the subject distance is calculated for each of the plurality of areas. A first operation for calculating data according to the above is performed, and based on the data obtained by this first operation, a plurality of adjacent areas within a predetermined range are selected from the plurality of areas and selected. Is performed second operation using the object image data of a plurality of area it was, characterized by calculating the final subject distance data from the second operation result.

In the distance measuring apparatus of the present invention, the pair of subject images are formed on the pair of line sensors by the light receiving lens, and the pair of subject images formed by the light receiving lens are controlled by the control means. It is controlled and converted into an electric signal by the pair of line sensors according to the light intensity. Further, the subject image data output from the pair of line sensors is read by the reading means, and the data corresponding to the subject distance is calculated by the calculating means based on the subject image data read by the reading means. Then, in the calculating means, the read subject image data is divided into a plurality of areas, and the first calculation for calculating data according to the subject distance is performed for each of the plurality of areas. Further, based on the data obtained by the first calculation, a plurality of adjacent areas within a predetermined range are selected from the plurality of areas, and the subject image data in the selected plurality of areas are used. 2 operations are performed. The final subject distance data is calculated from the result of the second calculation.

Further, in the distance measuring apparatus of the present invention, a pair of subject images are formed on the pair of line sensors by the light receiving lens, and the pair of subject images formed by the light receiving lens are controlled. It is controlled by the means and is converted into an electric signal by the pair of area sensors according to the light intensity. The subject image data output from the pair of area sensors is read by the reading means, and the data corresponding to the subject distance is calculated by the calculating means based on the subject image data read by the reading means. Then, in the calculating means, the read subject image data is divided into a plurality of areas, and the first calculation for calculating data according to the subject distance is performed for each of the plurality of areas. Based on the data obtained by the first calculation, a plurality of adjacent areas within a predetermined range are selected from the plurality of areas, and the subject image data in the selected plurality of areas is used to generate the second image. Calculation is performed. The final subject distance data is calculated from the second calculation result.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a distance measuring device according to a first embodiment of the present invention.

In FIG. 1, the subject image captured by the pair of light receiving lenses 11a and 11b is formed on the pair of line sensors 12a and 12b. In these line sensors 12a and 12b, the formed subject image is photoelectrically converted into an electric signal according to its light intensity. Then, the line sensors 12a and 12b
The integration control circuit 13 controls the integration operation.

Further, the outputs of the line sensors 12a and 12b are supplied to the A / D conversion circuit 14, and the analog electric signal obtained by photoelectrically converting the subject image is converted into a digital signal. The CPU 15 outputs various control signals and performs various calculations such as correlation / interpolation calculations.

In the distance measuring device having such a structure, as shown in FIG.
The line sensor field of view (distance measuring field of view) 19 in the photographing screen 18 as shown in (a) is divided into a plurality of first calculation areas E1 to E12 as shown in FIG. 2 (b), Data corresponding to the subject distance is calculated for each area by correlation calculation and interpolation calculation (first calculation).

Here, 20 in FIG. 2A is a person who is a subject. Further, in FIG. 2B, A is a second calculation area setting determination value that is a value according to a distance measurement error range that occurs due to a rotational deviation between the light receiving lens and the line sensor, and E13 is a first calculation area. The second calculation area is set when the first calculation data E5 to E8 is data within a predetermined difference A from the closest data.

The closest data and the area thereof are detected from the operation data of each area obtained by the above-mentioned first operation, and the adjacent area which is the data within the predetermined difference A from the closest data is selected. The predetermined difference A is, for example, −4 as shown in FIGS. 3A and 3B in the distance measuring device having the maximum rotation deviation generated when the distance measuring device is assembled.
The 5 ° and + 45 ° chart patterns 23 are distance measurement data differences when distances are measured, or values obtained by multiplying the data difference by a predetermined coefficient.

The selected adjacent area is set as one calculation area like the calculation area E13 as shown in FIG. 2B, and the sensor data of this calculation area is used to obtain data corresponding to the object distance. Is calculated by the correlation calculation and the interpolation calculation (second calculation). From this data, final output data (1 / subject distance data) is obtained.

For example, considering the case of measuring the distance of a person 20 as shown in FIG. 2A, the first calculation area E1
The ranging data from E12 to E12 has a distribution as shown in FIG. Then, since the calculation data of the calculation areas E5 to E8 for measuring the face of the person 20 is the data within the predetermined difference A from the closest data of the calculation area E5, the calculation areas E5 to E8 are the second calculation. The second calculation is performed by being set in the calculation area E13 for.

The low contrast area existing in the area which is the data within the predetermined difference A from the closest data is included in the calculation area for the second calculation. For example, even if the calculation area E6 or E7 shown in FIG. 2B has a low contrast, if the first calculation data in the areas E5 and E8 is data within the predetermined difference A from the closest data, calculation is performed. Areas E7 and E8 are also included in the calculation area E13 for the second calculation.

Next, referring to the flow chart of FIG.
A distance measuring operation of the distance measuring device according to the first embodiment will be described.

First, in step S1, the line sensors 12a and 12 are based on the photometric data, pre-integration data and the like.
The sensor sensitivity of b is set. Then, step S
In 2, integration is performed with the sensor sensitivity set in step S1. The integration control is performed by the integration control circuit 13.

In step S3, the sensor data obtained by the integration in step S2 is read out, and the A / D conversion circuit 1 is read.
A / D conversion by 4 is performed. And step S4
Then, the number of areas in which the first calculation is performed is set.

Next, in step S5, it is determined whether or not the small area has a low contrast before the first calculation is performed. If the contrast is not low, the process proceeds to step S6. If the contrast is low, the process proceeds to step S8.

In step S6, a correlation calculation is performed to find the shift amount of the data that maximizes the degree of coincidence of the data of the pair of windows in the first calculation area. Next, in step S7, an interpolation calculation is performed to find the fractional part of the discrete shift amount obtained in step S6.

Further, in step S8, the number of areas in which the first calculation is performed is decremented by 1. In the following step S9, it is determined whether or not the first calculation for all areas is completed. Here, if there is an area where the first calculation is not completed (n ≠ 0), the process proceeds to step S5, and if all areas are completed (n = 0), the process proceeds to step S10.

In step S10, the second calculation area is set. Next, in step S11, a correlation calculation is performed to obtain the shift amount of the data at which the degree of coincidence of the data of the pair of windows in the second calculation area is highest. Furthermore,
In step S12, an interpolating operation is performed to find the fractional part of the discrete shift amount obtained in step S11.

Then, in step S13, the shift amount S, which is the relative positional deviation amount of the subject image obtained in steps S11 and S12, is the reciprocal of the subject distance L according to the following equation (1). 1 / L).

1 / L = K × S + α (1) where K and α are constants determined by setting the distance measurement optical system, the sensor pitch of the line sensor, and the shift reference position for correlation calculation.

Here, the shift amount S is converted to 1 / L because the focus position of the taking lens is in a proportional relationship with 1 / L, and the output of the triangulation is also proportional to 1 / L in principle. Therefore, the calculation with 1 / L is simpler.

Next, the operation of the subroutine "second calculation area setting" of step S10 in the above-mentioned flowchart of FIG. 4 will be described with reference to the flowcharts of FIGS.

When this routine is entered, first, step S2
At 1, the shortest distance data is detected from the calculation result of the first calculation area. Next, in step S22, a group flag indicating whether or not the difference between the calculation data in the immediately preceding first calculation area and the closest data is within the predetermined difference A (within the predetermined difference A when F_GROUP = 1) ) Is cleared.

In step S23, the first area No. of the second calculation area is set. The data of the first calculation area number included in the (first calculation area No.) and the second calculation area is cleared. Further, in step S24, the first calculation area N
o. The counter (n) is set to 1.

Then, in step S25, the first calculation area No. It is determined whether or not the first calculation area represented by the counter (n) has low contrast. If the contrast is low, the process proceeds to step S26, and if not, the process proceeds to step S27.

In step S26, the group flag (F
It is determined whether _GROUP) is 0 or not. Here, if it is 0, the process proceeds to step S40, and if it is 1, step S40
Move to 31.

On the other hand, in step S27, the first calculation area No. The difference between the calculation data of the first calculation area represented by the counter (n) and the closest data is calculated, and the difference is C
An area D such as a register or RAM (not shown) in the PU 15
Memorized in.

Next, at step S28, a predetermined difference A from the data stored in the area D at step S27 is set.
The size of and is compared. As a result, if the data in the area D is smaller than the predetermined difference A, the process proceeds to step S29, and if it is larger, the process proceeds to step S33.

In step S29, it is determined whether or not the group flag (F_GROUP) is 0. If the determination result is 0, the process proceeds to step S30, and if the determination result is 1, the process proceeds to step S31.

In step S30, the first area No. of the second calculation area is set. First calculation area No. Counter (n)
No. of the first calculation area represented by Is set.

Then, in step S31, a second operation is started with the first operation area set in step S30 as the head.
The number of first calculation areas included in the calculation area is increased by one. Then, in step S32, the group flag (F
_GROUP) is set to 1.

In step S33, it is determined whether or not the group flag (F_GROUP) is 1.
Here, if the group flag (F_GROUP) is 1, the process proceeds to step S34, and if the group flag (F_GROUP) is 0, the process proceeds to step S40.
Move to.

In step S34, the reference first calculation area No. In the data m, the first calculation area No. immediately before is added. Is set. Next, in step S35, it is determined whether or not the immediately preceding first calculation area has a low contrast. If the contrast is low, the process proceeds to step S36, and if not, the process proceeds to step S36.
Move to 38.

In step S36, the above step S30 is performed.
The number of first calculation areas included in the second calculation area starting from the first calculation area set in step 1 is decreased by one. Succeedingly, in a step S37, the reference first calculation area No. The data m is decremented. After that, the above step S
Move to 35.

In step S38, the group flag (F_GROUP) is cleared. Then, in step S39, the first data of the closest data is stored in the second calculation area.
The calculation area is included (the first calculation area N of the second calculation area)
o. ≦ First calculation area No. of the nearest data <First area number of the second calculation area. + The number of first calculation areas included in the second calculation area). Here, if the first calculation area of the closest data is not included, the process proceeds to step S40, and if it is included, the present routine is exited.

In step S40, the first calculation area N
o. The counter (n) is incremented by 1. Next, in step S41, it is determined whether or not the difference between the first calculation data and the closest data and the magnitude difference with the predetermined difference A and other processing have been completed for all the first calculation areas. . If not completed, the process proceeds to step S25, and if completed, the process proceeds to step S42.

In step S42, the group flag (F
It is determined whether _GROUP) is 1 or not. The flag is 1
If so, the process proceeds to step S43, and if 0, the present routine is exited.

In step S43, the reference first calculation area No. The last first calculation area No. in the data m. Is set. Then, in step S44, the last first
It is determined whether the calculation area has a low contrast. If the contrast is low, the process proceeds to step S45, and if not, the routine exits.

In step S45, the above step S30 is performed.
The number of first calculation areas included in the second calculation area starting from the first calculation area set in step 1 is decreased by one. Next, in step S46, the reference first calculation area No. The data m is decremented. Further, in step S47, it is determined whether or not the immediately preceding first calculation area has a low contrast. If the contrast is low, the process proceeds to step S45. If not, the routine exits.

The processing in steps S34 to S37 and steps S43 to S47 is performed in the first calculation area E9 when the background of the person 20 has a low contrast in the scene shown in FIG. 2A, for example. The subsequent processing is included in the second calculation area E13, and is performed to prevent the second calculation area E13 from becoming too large and the second calculation time becoming longer than necessary.

Next, the processing of the correlation calculation will be described.

As shown in FIGS. 7A and 7B,
The line sensors 25a and 25b are composed of a plurality of photoelectric conversion elements, and have sensor data a1, a2, respectively.
, AN and b1, b2, ..., bN are output. Data of a predetermined range (hereinafter, windows) 26a and 26b are extracted from this sensor data.

The simplest method of extraction is to fix the window 26a and shift the window 26b by one sensor. Of course, the fixed side and the shift side may be reversed. Data of a pair of windows to be extracted is used, and the correlation amount F (n) is calculated by the following equation (2).
Is required.

[0055]

[Equation 1]

The highest degree of coincidence between the data in the pair of windows 26a and 26b is as shown in FIG.
F obtained by shifting the window 26b by one sensor
(N) is the minimum value (F (n) = Fmin), and the shift amount n = nFmin is the relative position shift amount of the subject image.

As a method of extracting a window, the method shown in FIG.
As shown in (a) and (b), a method of alternately shifting the windows 26a and 26b may be used. The equation for obtaining the correlation amount F (na, nb) in this case is as the following equation (3).

[0058]

[Equation 2]

The relative positional deviation amount nFmin is F (n
sum of na and nb (na + n) when a, nb) is the minimum
b).

Next, the process of interpolation calculation will be described.

Line sensor 25a obtained by correlation calculation
As shown in FIG. 8, the relative positional deviation amount of the subject image formed on the image pickup devices 25 and 25b is a discrete value corresponding to the sensor pitch of the line sensor, and this pitch width is the minimum of the distance measurement. It becomes the resolution. Therefore, if the distance measurement is performed only with the image shift amount obtained by the correlation calculation, the distance measurement accuracy becomes coarse.

Therefore, in order to improve the accuracy of distance measurement, the following interpolation calculation is performed by using the discrete correlation amount F (n).

Generally, in the interpolation calculation, as shown in FIGS. 10A and 10B, Fmin, which is the minimum value of the correlation amount F (n), and the shift amounts n _Fmin −1 before and after it, n _Fmin
Fmns and Fpls at +1 are used to calculate Fm
the amount of deviation Δn of the shift amount n _FminR to give the shift amount n _Fmin and the true minimum value FminR to give in, Fmns,
It is obtained by the following equation (4) or equation (5) according to the magnitude relation of Fpls.

[0064]

[Equation 3]

[0065]

[Equation 4]

According to the interpolation amount Δn obtained above, the true image shift amount n _FminR is as follows: Fmns> Fpls (see FIG. 10A) n _FminR = n _Fmin + Δn (6) When Fmns ≦ Fpls (Refer to FIG. 10B) n _FminR = n _Fmin -Δn (7)

As described above, according to the first embodiment,
It is possible to reduce the distance measurement error caused by the rotation deviation between the light receiving lens and the line sensor.

Next, a second embodiment of the present invention will be described.

FIG. 11 is a block diagram showing a schematic configuration of a distance measuring device according to the second embodiment of the present invention.

In the above-described first embodiment, a value corresponding to the distance measurement error range generated by the rotation deviation of the light receiving lens of the distance measurement device and the line sensor for selecting the calculation area for performing the second calculation. While the predetermined value A which is a fixed value is a fixed value, in the second embodiment, the predetermined value A is an adjustment value according to the rotation deviation that the distance measuring device itself has.
This is stored in the storage means.

In FIG. 11, a pair of light receiving lenses 31a
And 31b, the subject images captured are formed on the pair of line sensors 32a and 32b. In these line sensors 32a and 32b, the formed subject image is photoelectrically converted according to its light intensity and converted into an electric signal. Then, the line sensors 32a and 32b
The integration control circuit 33 controls the integration operation.

The outputs of the line sensors 32a and 32b are supplied to the A / D conversion circuit 34, and the analog electric signal obtained by photoelectrically converting the subject image is converted into a digital signal. The CPU 35 outputs various control signals and performs various calculations such as correlation / interpolation calculations. The CPU 35 includes a nonvolatile memory 3 such as an EEPROM as a storage unit.
6 is connected.

In such a structure, the adjustment value is as shown in FIG.
It is a value corresponding to the difference in the distance measurement data when the distances of the respective charts arranged at the same distance are measured using the two types of charts having the patterns P of −45 ° and + 45 ° as shown in FIG. . For this, the distance measurement data difference may be used as it is, or may be obtained by multiplying the distance measurement data difference by a predetermined coefficient.

Further, the angles of the patterns of the two types of charts may be obtained in combinations other than -45 ° and + 45 °.

Next, with reference to the flow chart of FIG. 12, an adjustment value A which is a value corresponding to a range-finding error range which is generated due to a rotational deviation between the light-receiving lens and the line sensor of the range-finding apparatus according to the second embodiment. The calculation procedure of will be described.

The other operations are the same as those in the first embodiment described above, and the description thereof will be omitted.

When this routine is entered, first, step S5
At 1, the -45 ° chart is set at a predetermined position. Then, in step S52, the -45 ° chart is distance-measured to obtain distance-measurement data AFMNS.

In step S53, the + 45 ° chart is set at a predetermined position. Next, in step S54, the distance of the + 45 ° chart is measured, and the distance measurement data AF
PLS is required.

Then, in step S55, the following (8)
The adjustment value A is calculated by the formula. A = | AFMNS-AFPLS | (8) When a predetermined coefficient K is applied, it is calculated by the following equation (9). A = | AFMNS-AFPLS | × K (9) As described above, according to the second embodiment, the second calculation can be performed in the minimum necessary area, so that the distance measurement time is shortened. The distance measurement accuracy is also improved.

Next explained is the third embodiment of the invention.

FIG. 13 is a block diagram showing a schematic configuration of a distance measuring device according to the third embodiment of the present invention.

The third embodiment is a range finder mounted on a camera in which the focal length of the taking lens is variable.
The second calculation is not performed on the short focus side where the depth of field becomes large, but the distance measurement data is selected by the closest selection from the plurality of distance measurement data by the first calculation, and the second calculation is performed only on the long focus side. Is to do.

In FIG. 13, a pair of light receiving lenses 41a is provided.
And 41b, the subject image is formed on the pair of line sensors 42a and 42b. In these line sensors 42a and 42b, the formed subject image is photoelectrically converted into an electric signal according to its light intensity. Then, the line sensors 42a and 42b
The integration control circuit 43 controls the integration operation.

The outputs of the line sensors 42a and 42b are supplied to the A / D conversion circuit 44, and the analog electric signal obtained by photoelectrically converting the subject image is converted into a digital signal. The CPU 45 outputs various control signals and performs various calculations such as correlation / interpolation calculations. A focal length detection circuit 46 that detects the focal length of the taking lens is connected to the CPU 45.

Next, the distance measuring operation of the distance measuring device having such a structure will be described with reference to the flowchart of FIG.

First, in step S61, photometric data,
Based on the pre-integration data and the like, the line sensors 42a and 4a
The sensor sensitivity of 2b is set. Next, in step S62, integration is performed based on the sensor sensitivity set in step S61. The integration control is performed by the integration control circuit 42.

In step S63, the above step S62 is performed.
The sensor data is read out by the integration of, and A / D conversion is performed by the A / D conversion circuit 44. And step S
In 64, the number of areas for performing the first calculation is set.

In step S65, it is determined whether the first calculation area has a low contrast before the first calculation is performed. If the contrast is not low, the process proceeds to step S66. If the contrast is low, the process proceeds to step S68.

In step S66, a correlation calculation is performed to obtain the shift amount of the data that maximizes the degree of coincidence of the data of the pair of windows in the first calculation area. Next, in step S67, an interpolation calculation is performed to find the fractional part of the discrete shift amount obtained in step S66.
Then, in step S68, the number of areas in which the first calculation is performed is decremented by 1.

Here, in step S69, it is determined whether or not the first calculation for all areas is completed. If there is an area for which the calculation is not completed (n ≠ 0), the process proceeds to step S65, and if all areas are completed (n = 0)
Moves to step S70.

In step S70, it is determined whether or not the focal length f of the taking lens detected by the focal length detecting circuit 46 is larger than a predetermined value. If the focal length f is larger, the process proceeds to step S71, and if the focal length f is smaller, the process proceeds to step S74.

In step S71, the second calculation area is set. Next, in step S72, a correlation calculation is performed to obtain a data shift amount that maximizes the degree of coincidence of the data of the pair of windows in the second calculation area. In the following step S73, an interpolation calculation is performed to find the fractional part of the discrete shift amount obtained in step S72.

On the other hand, in step S74, the shortest distance data is selected from the calculation data in the first calculation area.

Then, in step S75, the shift amount S, which is the relative positional shift amount of the subject image obtained in steps S66 and S67 or steps S72 and S73, is performed.
Is converted into data (1 / L) which is the reciprocal of the subject distance L.

The method of selecting the distance measurement data on the short focus side is not limited to the closest selection, but an average value may be obtained or another selection method may be used.

As described above, according to the third embodiment,
It is possible to shorten the distance measurement time on the short focus side, which has a high shooting frequency.

Next explained is the fourth embodiment of the invention.

FIG. 15 is a block diagram showing a schematic structure of a distance measuring device according to a fourth embodiment of the present invention.

While the line sensor is used as the light receiving element in the above-described first to third embodiments, the area sensor is used in the fourth embodiment.

In FIG. 15, a pair of light receiving lenses 51a is provided.
The subject images captured by the and 51b are formed on the pair of area sensors 52a and 52b. In these area sensors 52a and 52b, the formed subject image is photoelectrically converted according to its light intensity and converted into an electric signal. Then, the area sensors 52a and 52b
The integration control circuit 53 controls the integration operation.

The outputs of the area sensors 52a and 52b are supplied to the A / D conversion circuit 54, and the analog electric signal obtained by photoelectrically converting the subject image is converted into a digital signal. The CPU 55 outputs various control signals and performs various calculations such as correlation / interpolation calculations. A non-volatile memory 56 such as an EEPROM is connected to the CPU 55, and a focal length detection circuit 57 for detecting the focal length of the photographing lens is also connected.

In such a configuration, the predetermined value A, which is a value corresponding to the distance measurement error range caused by the rotation deviation between the light receiving lens of the distance measurement device and the line sensor, is set as E as the adjustment value.
It is stored in a non-volatile memory 56 such as an EPROM. Then, based on this adjustment value, execution or non-execution of the second calculation is selected according to the focal length of the taking lens.

As described above, according to the fourth embodiment,
Even when an area sensor is used instead of the line sensor, the same effects as those of the above-described first to third embodiments can be obtained.

According to the above embodiment of the present invention,
The following configuration can be obtained.

That is, (1) a light-receiving lens for forming a pair of subject images on a pair of line sensors, and a pair of subject images formed by the light-receiving lens are converted into electric signals according to the light intensity. A pair of line sensors, a control means for controlling the operation of the pair of line sensors, a reading means for reading subject image data output from the pair of line sensors, and a reading means based on the subject image data read by the reading means. And a calculation means for calculating data according to the subject distance, the calculation means divides the read subject image data into a plurality of areas, and according to the subject distance for each of the plurality of areas. A plurality of adjacent areas within a predetermined range are selected from the plurality of areas based on the data obtained by the first operation. Performing a second calculation using the object image data of a plurality of area that, the distance measuring apparatus characterized by calculating the final subject distance data from the results of this second operation.

(2) A light receiving lens for forming a pair of subject images on a pair of line sensors, and a pair of pair for converting the pair of subject images formed by the light receiving lens into electric signals according to the light intensity. An area sensor, control means for controlling the operation of the pair of area sensors, and reading means for reading subject image data output from the pair of area sensors,
In a distance measuring device including a calculation means for calculating data according to a subject distance based on the subject image data read by the reading means, the calculation means stores the read subject image data in a plurality of areas. The first calculation is performed by dividing and performing data calculation according to the subject distance for each of the plurality of areas. Based on the data obtained by the first calculation, a plurality of adjacent areas within a predetermined range from the plurality of areas are calculated. A distance measurement characterized by selecting an area, performing a second calculation using the subject image data in the selected plurality of areas, and calculating the final subject distance data from the second calculation result. apparatus.

(3) In a plurality of adjacent areas used in the second calculation, the first calculation result is the closest data and the data within a predetermined difference, (1),
The distance measuring device according to (2).

(4) The predetermined range for selecting a plurality of adjacent areas used in the second calculation is set at the time of manufacturing the distance measuring device and stored in a non-volatile memory such as an EEPROM. Characteristic above (1),
The distance measuring device according to (2).

(5) The above-mentioned predetermined range has a linear pattern in which the inclination is reversed and is oblique, and is set based on the distance measurement data difference when distance measurement is performed on two types of charts installed at the same distance. The distance measuring device as described in (1) or (2) above.

[0110]

As described above, according to the present invention, it is possible to provide a distance measuring device having a small distance measuring error caused by an assembly error between the AF sensor and the light receiving lens without using a special sensor.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a distance measuring device according to a first embodiment of the present invention.

FIG. 2 illustrates a method of setting a second calculation area,
(A) is a diagram showing an example of a positional relationship among a photographing screen, a distance measuring field of view, and a subject during photographing of a person, and (b) is a first and second calculation areas and a case of distance measuring the scene (a) It is the figure which showed the example of 1 calculation data.

FIG. 3 is a chart for obtaining an adjustment value A that is a value according to a distance measurement error range that occurs due to a rotational shift between a light receiving lens of a distance measuring device and a line sensor, and (a) is −45 °.
2B is a diagram showing an example of the chart of FIG. 4B, and FIG.

FIG. 4 is a flowchart illustrating a distance measuring operation of the distance measuring device according to the first embodiment.

FIG. 5 is a step S10 in the flowchart of FIG.
5 is a flowchart illustrating an operation of a subroutine "second calculation area setting" in step S4.

FIG. 6 is a step S10 in the flowchart of FIG.
5 is a flowchart illustrating an operation of a subroutine "second calculation area setting" in step S4.

FIG. 7 is a diagram illustrating a window shift method for correlation calculation.

FIG. 8 is a correlation data graph showing a correlation value for each shift value.

FIG. 9 is a diagram illustrating another example of the window shift method of the correlation calculation.

FIG. 10 is a diagram illustrating an interpolation calculation.

FIG. 11 is a block diagram showing a schematic configuration of a distance measuring device according to a second embodiment of the present invention.

FIG. 12 is a flowchart illustrating a procedure for calculating an adjustment value A, which is a value corresponding to a range-finding error range that occurs due to a rotation deviation between a light-receiving lens and a line sensor of the range-finding apparatus according to the second embodiment.

FIG. 13 is a block diagram showing a schematic configuration of a distance measuring device according to a third embodiment of the present invention.

FIG. 14 is a flowchart illustrating a distance measuring operation of the distance measuring device according to the third embodiment.

FIG. 15 is a block diagram showing a schematic configuration of a distance measuring device according to a fourth embodiment of the present invention.

FIG. 16 is a front view schematically showing a range finder in which the line connecting the optical axes of the pair of light receiving lenses and the line connecting the centers of the pair of line sensors have an angle and are assembled.

17A and 17B show image forming positions on a line sensor according to a subject pattern, where FIG. 17A is a diagram showing an example of a diagonally upward rising pattern subject, and FIG. 17B is an example of a vertical pattern subject. FIG. 6 (c) is a diagram showing an example of an obliquely upward rising pattern subject, and FIG. 7 (d) is a diagram showing an example of image forming positions on the line sensors S1 and S2 of an upwardly rising oblique pattern subject. Is a line sensor S for a vertical pattern subject
FIGS. 1A and 1B are diagrams showing examples of image forming positions on S1 and S2, and FIG. 6F is a diagram showing an example of image forming positions on the line sensors S1 and S2 of an obliquely upward oblique pattern subject.

FIG. 18 is a diagram showing a schematic configuration of a passive distance-measuring sensor in which a third line sensor is arranged in a direction perpendicular to one line sensor of a pair of normal line sensors.

[Explanation of symbols]

11a, 11b light receiving lens, 12a, 12b, 25a, 25b line sensor, 13 integral control circuit, 14 A / D conversion circuit, 15 CPU, 18 Shooting screen, 19 line sensor field of view (distance measuring field), 20 subject (person), 23 chart patterns, 26a, 26b windows, E1 to E12 first calculation area, E13 Second calculation area.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G06F 17/17 G03B 3/00 AF term (reference) 2F112 AC03 AC06 BA06 BA09 CA02 FA03 FA07 FA08 FA21 FA29 FA36 FA39 FA45 2H011 BA05 BB04 2H051 BB07 DA07 DA26 DA30 DA31 DB01 5B056 BB00 HH00

Claims (4)

[Claims] 1. A light-receiving lens for forming a pair of object images on a pair of line sensors, and a pair of lines for converting the pair of object images formed by the light-receiving lens into electric signals according to light intensity. A sensor, a control means for controlling the operation of the pair of line sensors, a reading means for reading the subject image data output from the pair of line sensors, and a subject distance based on the subject image data read by the reading means. In the distance measuring device including a calculation means for calculating data according to the above, the calculation means divides the read subject image data into a plurality of areas, and obtains data according to the subject distance for each of the plurality of areas. A first calculation is performed, and based on the data obtained by this first calculation, a plurality of adjacent areas within a predetermined range are selected from the plurality of areas, and the selected plurality of areas are selected. Performing a second calculation using the subject image data of the inner,
A distance measuring device which calculates final subject distance data from the result of the second calculation. 2. A light receiving lens for forming a pair of subject images on a pair of line sensors, and a pair of areas for converting the pair of subject images formed by the light receiving lenses into electric signals according to light intensity. A sensor, control means for controlling the operation of the pair of area sensors, reading means for reading subject image data output from the pair of area sensors, and subject distance based on the subject image data read by the reading means. In the distance measuring device including a calculation means for calculating data according to the above, the calculation means divides the read subject image data into a plurality of areas, and the data according to the subject distance for each of the plurality of areas. The first calculation is performed, and based on the data obtained by the first calculation, a plurality of adjacent areas within a predetermined range are selected from the plurality of areas, and the selected plurality of areas are selected. Performing a second calculation using the subject image data in the A, the distance measuring apparatus characterized by calculating the final subject distance data from the second operation result. 3. A plurality of adjacent areas used in the second calculation have a first calculation result which is within a predetermined difference from the closest data, and the predetermined range is set at the time of manufacture and stored in a nonvolatile memory. Stored in memory,
The distance measuring device according to 2. 4. The distance measuring device according to claim 1, wherein the second calculation is executed only when the focal length of the taking lens is within a predetermined range.