JPH1184223A - Automatic position detection method and automatic position detection device - Google Patents

Abstract

(57) [Problem] To provide an automatic focus detection method for automatically focusing on an optical system, and to provide an automatic position detection method capable of accurately and quickly detecting a position of an object. SOLUTION: The lens package 1 is moved with respect to an LD package 11, and the lens package 103 is moved continuously while moving a position search range.
An image obtained through the second lens 12a is captured, stored in the frame buffer 121 for each frame, and the image stored in the frame buffer 121 is preset according to the shape of the surface of the LD package 11 facing the lens 12a. By performing pattern matching using the normalized template pattern and the normalized correlation, a normalized correlation value of each image is obtained, and the position where the image having the maximum normalized correlation value is obtained is determined as the optimal position of the lens package 12 with respect to the LD package 11. To detect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic position detecting method and an automatic position detecting device, and more particularly to an automatic position detecting method and an automatic position detecting device for automatically adjusting the focus of an optical system. In recent years, demand for bidirectional optical communication units is expected to increase with the spread of optical cable networks. For this reason, a technique for mass-producing bidirectional optical communication units is desired.

A two-way optical communication unit has an optical system having a complicated configuration. For this reason, for mass production of the bidirectional optical communication unit, it was necessary to efficiently focus an optical system having a complicated configuration.

[0003]

2. Description of the Related Art FIG. 13 shows a configuration diagram of a two-way communication module used in an optical cable network. The two-way communication module 1 emits light according to information and receives the light passing through the optical fiber cable 2, an LD package 11, and a lens package 12 for increasing the efficiency of optical coupling with the optical fiber cable 2. , Optical fiber cable 2
Are coupled to each other to constitute a prism unit 13 for distributing transmission light and reception light.

[0004] The LD package 11 converts a light supplied from the optical fiber cable 2 into an electric signal, and a light emitting element 11a for converting an electric signal corresponding to information to be transmitted into laser light. The light receiving element 11b is mounted on one package 11c. The light emitting element 11a is configured by a laser diode or the like, and the light receiving element 11b is configured by a photodiode or the like.

The lens package 12 includes a lens 12a,
The LD package 11 is composed of a lens holder 12b.
Are arranged so as to face the light emitting / receiving surface of the light emitting element. Lens 12a
Is held by the lens holder 12b, and the LD package 1
The light emitted from one light emitting element 11a is condensed and supplied to the optical fiber cable 2, and the light transmitted through the optical fiber cable 2 is condensed and supplied to the light receiving element 11b of the LD package 11.

[0006] The lens holder 12b is an LD package 1
The package 11c is held in close contact with the light transmitting / receiving surface of the package 11c,
The LD package 11 and the lens package 12 are positioned. LD package 11 and lens package 12
The transmission / reception efficiency of the bidirectional optical communication unit 1 is determined according to the positional relationship on the coordinate X and Y planes. Further, the prism section 13 includes a total reflection mirror 1 on the surface of the prism 13a.
3b and a half mirror 13c are formed. Output light emitted by the light emitting element 11a of the LD package 11 is condensed by the lens 12a of the lens package 12 and supplied to the prism unit 13.

In the prism section 13, first, the prism 13
a of the prism 13a and supplied to a total reflection mirror 13b formed at the other end of the prism 13a. The output light is totally reflected by the total reflection mirror 13b, and the half mirror 13 formed at one end of the prism 13a via the prism 13a.
c. The output light is reflected by the half mirror 13c toward the other end of the prism 13a. Prism 1
The other end of 3 a is coupled to the end of the optical fiber cable 2, and output light is supplied to the optical fiber cable 2.

The incident light supplied from the optical fiber cable 2 is input from the other end of the prism 13a and supplied to the half mirror 13c. The incident light supplied to the half mirror 13c passes through the half mirror 13c and is supplied to the lens 12a of the lens package 12. The incident light supplied to the lens 12a is condensed by the lens 12a and is applied to the light receiving element 11b of the LD package 11.

LD package 11 and lens package 1
2, the LD package 11 and the lens package 12 are positioned using a lens position adjusting device. In the conventional lens position adjusting device, in order to perform the position adjustment efficiently, the light emission and reception of the light emitting element 11a and the light receiving element 11b are not detected, and the image formation through the lens 12a of the lens package 12 of the LD package 11 is performed. A so-called passive adjustment method of adjusting the positional relationship between the LD package 11 and the lens package 12 by searching for an image point is employed.

In such a lens adjusting device, the LD package 11 is fixed to the LD stage, the lens package 12 is fixed to the lens stage, the relative position between the LD stage and the lens stage 12 is set to a predetermined position, and the image is taken. The apparatus captures an image of the LD package 11 through the lens 12a of the lens package 12, and evaluates the luminance dispersion at a specific position of the image captured through the lens 12a and the luminance difference between frames. Conventionally, the above operation was repeated,
In the best case, the position of the image where the evaluation value was obtained was detected as the optimum position.

Next, a description will be given of luminance dispersion, which is a conventional evaluation method, with reference to the drawings. FIG. 14 is a view for explaining a conventional lens position detecting method. FIG. 14A shows the entire operation, and FIG. 14B shows the operation at a predetermined position. First,
As shown in FIG. 14A, at time t30, the lens package 12 is moved to the position P0, an image is taken, and the image is evaluated based on the luminance dispersion. Next, when the evaluation at the position P0 is completed, at a time t31, the lens package 12 is moved to the position P1.
Is moved to capture an image, and the image is evaluated based on the luminance dispersion. By repeating the above operation, the image at each position is evaluated, and the optimum position is detected.

As shown in FIG. 14B, the operation at each of the positions P0, P1,... Is performed by moving the lens package 12 to each of the positions P0, P1,.
Step S4- of imaging an image through a lens by an imaging device
2. It comprises a step S4-3 of obtaining a luminance variance at a specific position of the image taken in step S4-2 and calculating an evaluation value. Move the lens package 12 to each of the positions P0, P1,.
In the step S4-1 for moving the lens stage, there is a loss due to starting and stopping for moving and stopping the lens stage by a very small distance, and it takes 100 to 400 msec.

FIG. 15 is a diagram for explaining a lens position evaluation method based on luminance diffusion. FIG. 15A shows an in-focus image, FIG. 15B shows an out-of-focus image,
FIG. 15C shows a luminance characteristic according to a position. FIG.
The luminance distribution of the focused image as shown in FIG.
As shown by the solid line in FIG. 15C, the variance according to the position decreases. In addition, as shown by the broken line in FIG. 15C, the variance according to the position is large in the luminance distribution of the image that is not focused as shown in FIG.

Therefore, in the conventional lens position adjusting device,
The position where the variance according to the position is smallest as shown by the solid line in FIG. 15C is evaluated as the optimum position, and the position of the lens package 12 with respect to the LD package 11 is adjusted. The package 11 and the lens package 12 were positioned by laser welding.

[0015]

However, in the conventional lens position detection method, the image reading and the evaluation value calculation processing are executed while the position is slightly moved, so that the number of times of starting and stopping the lens is large, Since the loss of the moving time increases, there is a problem that the processing takes a long time.

Further, in the conventional lens position detecting method, the position where the luminance variance at the specific position of the image picked up through the lens is the smallest is detected as the optimum position. In the case of a complicated shape, the position of the image where an image irrelevant to a specific position is formed is determined as the optimal position of the lens, the lens is positioned, and the communication efficiency deteriorates. There was a problem.

The present invention has been made in view of the above points, and an object of the present invention is to provide an automatic position detecting method and an automatic position detecting device capable of accurately and quickly detecting a position of an object.

[0018]

According to a first aspect of the present invention, an image whose positional relationship with an optical system is to be adjusted is picked up through the optical system, and the optical system with respect to the image is taken in accordance with the picked-up result. In the automatic position detection method for detecting the position of the optical system, an image capturing step of controlling the positional relationship of the optical system with respect to the image to capture an image in a predetermined position search range, and the image captured in the image capturing step and the image An evaluation value calculating step of calculating an evaluation value corresponding to a deviation from an image set in advance, and an optimal position of the optical system with respect to the image according to a normalized correlation value calculated in the correlation calculating step. Detecting a position.

According to the first aspect, the positional relationship of the optical system with respect to the image is controlled to pick up an image in a predetermined position search range, and the difference between the picked-up image and the image set in advance with respect to the image. By calculating the evaluation value according to the calculated value and detecting the optimum position of the optical system with respect to the image according to the calculated evaluation value, the evaluation value is calculated according to the shape even if the shape of the image is complicated. Therefore, the position of the image can be reliably detected, and the positional relationship of the optical system with respect to the position of the image can be accurately detected.

According to a second aspect of the present invention, the image of the predetermined position search range is continuously captured in the image capturing process, and the image is held for each frame. According to the second aspect, by continuously capturing images in a predetermined position search range and holding the image for each frame, it is not necessary to repeatedly move and stop the capturing position, so that the capturing can be performed in a short time. And the overall processing time can be reduced.

According to a third aspect of the present invention, the imaging step and the evaluation value calculating step are performed in parallel. According to the third aspect, by executing the imaging process and the evaluation value calculation process in parallel, the imaging and the evaluation value calculation are performed simultaneously, and the overall processing time can be reduced. A fourth aspect of the present invention is characterized in that the position determination step determines a position at which an image of a maximum value is captured among the correlation values calculated in the correlation calculation step as the optimum position.

According to the fourth aspect, the position at which the image of the maximum value among the correlation values calculated in the evaluation value calculation process is taken is determined as the optimum position, so that the image most correlated with the preset image is determined. Can be determined as the optimum position, so that the optimum position can be reliably detected. Preferably, the inclination of the evaluation value calculated in the evaluation value calculation step is detected by the position determination step, and when the inclination of the evaluation value is inverted, the evaluation value immediately before the inversion is used as the maximum value. The position where the image of the value is captured is determined as the optimum position.

According to the fifth aspect, the inclination of the evaluation value is detected, and when the inclination of the normalized correlation value is inverted, the evaluation value immediately before the inversion is set to the maximum value, and the position where the image of the maximum value is captured is optimized. By judging the value, even if all the evaluation values do not exist, the maximum value can be detected, so that the calculation of the evaluation value can be omitted, and thus high-speed processing can be performed. Claim 6
Has a position search range setting step of setting a predetermined range around the optimal position determined in the position determination step as a position search range, and in the position search range setting step, On the other hand, the imaging step, the evaluation value calculating step, and the position determining step are performed.

According to the present invention, a predetermined range around the optimum position determined in the position determination process is set as a position search range, and the set position search range is again imaged and evaluated. By executing the position determination process, the position search range is sequentially narrowed, and the optimum position can be accurately detected. The automatic position detection device according to claim 7, wherein an image whose positional relationship with the optical system is to be adjusted is captured via the optical system, and the position of the optical system with respect to the image is detected in accordance with a captured result. Imaging means for controlling a positional relationship of the optical system with respect to an image, and imaging an image in a predetermined position search range,
An evaluation value calculation unit that calculates an evaluation value corresponding to a correlation between the image captured by the imaging unit and a predetermined image that is set in advance according to the image; and an evaluation value calculated by the evaluation value calculation unit. And a position determining means for detecting an optimum position of the optical system with respect to the image in response to the determination.

According to the seventh aspect, the positional relationship of the optical system with respect to the image is controlled so that an image in a predetermined position search range is captured by the image capturing means, and the image and the image captured by the evaluation value calculating means are controlled. By calculating an evaluation value according to a deviation from a preset image and detecting an optimum position of the optical system with respect to the image according to the evaluation value calculated by the position determination unit, even when the shape of the image is complicated. Since the evaluation value is calculated according to the shape, the position of the image can be reliably detected, so that the positional relationship of the optical system with respect to the position of the image can be accurately detected.

[0026]

FIG. 1 is a block diagram showing a first embodiment of the present invention. Automatic focus adjustment device 100 of the present embodiment
Is for adjusting the positional relationship between the LD package 11 and the lens package 12 of the bidirectional optical communication unit 1.
LD stage 101 for moving D package 11, L
LD stage controller 102 for controlling movement of D stage 101, lens stage 103 for moving lens package 12, lens stage controller 104 for controlling movement of lens stage 103, image of LD package 11 through lens 12a of lens package 12. 105, an illumination light source 106 for inspecting illumination light via the microscope 105, a CCD camera 107 for capturing an image enlarged by the microscope 105, a microscope 105, C
A camera stage 108 for moving the CD camera 107,
A camera stage controller 109 for controlling the movement of the camera stage 108; an image processing unit 110 for performing processing for detecting the position of the focal point in accordance with the image captured by the CCD camera 107; and a TV for displaying the image captured by the CCD camera 110 It comprises a monitor 111, a main controller 109 for controlling the LD stage controller 102, the lens stage controller 104, and the camera stage controller 109 according to commands from the image processing unit 110.

The LD package 11 is fixed to the LD stage 101. The LD stage 101 is connected to the LD stage controller 102, and moves the LD package 11 in the three-dimensional coordinates X, Y, Z and the rotation angle θ direction according to a drive control signal supplied from the LD stage controller 102. LD stage controller 10
2 is connected to the main controller 112 and supplies a drive control signal to the LD stage 101 in response to a command supplied from the main controller 112.

The lens package 12 is fixed to the lens stage 103. The lens stage 103 is connected to a lens stage controller 104, and moves the lens package 12 in two-dimensional coordinates X and Y in accordance with a drive control signal supplied from the lens stage controller 104.
Move in the direction. Lens stage controller 104
Is connected to the main controller 112 and supplies a drive control signal for driving the lens stage 103 in response to a command supplied from the main controller 112.

The camera stage 108 includes the microscope 10
5. The illumination light source 106 and the CCD camera 107 are fixed. The camera stage 108 is connected to a camera stage controller 109, and moves the microscope 105, the illumination light source 106, and the CCD camera 107 in three-dimensional coordinates X, Y, and Z directions according to a drive control signal supplied from the camera stage controller 109. Move. The camera stage controller 109 is connected to the main controller 112 and supplies a drive control signal to the camera stage 108 in response to a command supplied from the main stage controller 109.

The main controller 112 is connected to the image processing unit 110 and responds to a command supplied from the image processing unit 110 to operate the LD stage controller 10.
2. Commands are supplied to the lens stage controller 104 and the camera stage controller 109. The image processing unit 110 is connected to the CCD camera 110,
An image supplied from the CD camera 110 is compared with a preset template image, a normalized correlation value between the two is calculated, and a command is sent to the main controller 112 according to the calculated normalized correlation value. Position adjustment between the lens 11 and the lens package 12 on a plane in the X and Y directions is performed.

A TV monitor 111 is connected to the image processing unit 110. The TV monitor 111 has a CC
An image captured by the D camera 110, an image in the process of processing, and the like are displayed. Here, the configuration of the image processing unit 110 will be described with reference to the drawings. FIG. 2 is a block diagram of the image processing unit according to the first embodiment of the present invention.

The image processing unit 110 includes a CCD camera 107
An image input interface unit 120 for inputting an image picked up by the camera, a frame buffer 121 for holding an image picked up by the CCD camera 107 for each frame, and a two-dimensional shape of a surface of the LD package 11 facing the lens package 12. Based on a template holding unit 122 holding a preset template pattern, a program memory 123 storing an image processing program, an interface unit 124 communicating with the main controller 112, and an image processing program stored in the program memory 123. To control the main controller 112 to obtain an image obtained through the lens package 12 of the LD package 11, hold the image in the frame buffer 121, and hold the lens package 12 held in the frame buffer 121.
CPU 125 that performs pattern matching between the image of the LD package 11 obtained through the above and the template pattern held in the template holding unit 122 to calculate a normalized correlation value at a predetermined recognition point, and serves as a working memory of the CPU 125. It comprises a RAM 126, an image input interface unit 120, a frame buffer 121, a template holding unit 122, a program memory 123, an interface unit 124, and a bus 127 connecting the CPU 125.

At the time of processing, the image processing unit 110 stores the image processing program stored in the program memory 123 in R
It is stored in the AM 126 and the processing is executed by the CPU 125. At the time of executing the program, an image captured by the CCD camera 107 is input to the bus 127 via the image input interface unit 120 and is sequentially transmitted to the frame buffer 1.
21.

In the template holding unit 122, for example,
A plurality of template patterns are held.
As the template pattern, when the positional relationship between the LD package 11 and the lens package 12 is correct, a desired pattern is selected from the shape of an image to be obtained via the lens 12a on the surface of the LD package 11 facing the lens package 12. Is being held.

For example, as a template pattern,
The shape of the light receiving surface of the light receiving element 11b of the LD package 11,
The shape of the side surface of the substrate of the light emitting element 11a is selected. CPU
Reference numeral 125 denotes a template pattern preset in the template pattern holding unit 122 and the frame buffer 12.
The image stored in No. 1 is subjected to pattern matching by normalized correlation, evaluation is performed, and the optimum position of the lens package 12 is detected.

Next, the operation of the image processing unit 110 will be described with reference to the drawings. FIG. 3 shows a processing flowchart of the image processing unit according to the first embodiment of the present invention. When the image processing program stored in the program memory 123 is started, the image processing unit 110 first supplies a command to move the LD stage 101, the lens stage 104, and the camera stage 108 to the main controller 112 (Step S1- 1).

The main controller 112 supplies a command to the LD stage controller 102, the lens stage controller 104, and the camera stage controller 109 in response to a command from the image processing unit 110. L
The D stage controller 102, the lens stage controller 104, and the camera stage controller 109
LD according to a command from the main controller 112
A drive control signal is supplied to the stage 101, the lens stage 103, and the camera stage.

The LD stage 101 is controlled in accordance with a drive control signal supplied from the LD stage controller 102 so as to be fixed at a predetermined position on a plane in the coordinates X and Y directions, and the coordinates Z The direction is controlled so that the LD package 11 and the lens package 12 are in close contact with each other. Further, the camera stage 108 is fixed at a predetermined position set in advance with respect to the LD package 11 according to a drive control signal from the camera stage controller 109. Further, the lens stage 103 is controlled to move within a preset position search range.

In step S1-1, the LD stage 10
1. At the same time as driving the lens stage 103 and the camera stage 108, the variable i for determining the number of frames is set to “0”.
(Step S1-2). Next, an image taken by the CCD camera 107 is read and stored in the frame buffer 121 as an image corresponding to the variable i-th frame (step S1-3). At this time, step S
The position information Zi of the lens stage 103 at the time of reading the image of the variable i frame acquired in 1-3 is acquired from the lens stage controller 104 via the main controller 112 and stored in the RAM 126 (step S1-
4).

Steps S1-3 and S1-4 are repeated in a preset position search range in which the lens stage 103 moves, to obtain images for N + 1 frames and positional information Zi of the lens stage 103 when the images have been obtained. (Steps S1-5, S1-6). Next, in the image processing program of the image processing unit 110, the variable i is returned to the initial value “0” again (step S1-7), and the template held in the template pattern holding unit 122 for the i-th frame image. A pattern and pattern matching are performed to calculate a normalized correlation value Ci (step S1-
8).

Next, in step S1-8, the calculated normalized correlation value Ci is compared with the largest normalized correlation value Cmax among the normalized correlation values calculated so far (step S1).
-9). In step S1-9, the normalized correlation value Ci calculated this time in step S1-8 is larger than the largest normalized correlation value Cmax among the normalized correlation values calculated so far.
That is, when Cmax <Ci, step S1-8 is executed.
Then, the normalized correlation value Ci calculated this time is set to the maximum normalized correlation value Cmax (step S1-10).

In step S1-9, step S1 is executed.
If the normalized correlation value Ci calculated this time at -8 is smaller than the maximum normalized correlation value Cmax among the normalized correlation values calculated so far, the largest normalized correlation value among the normalized correlation values calculated so far is calculated. The correlation value Cmax is directly set to the maximum normalized correlation value Cmax. Steps S1-8 to S1
-9 is performed for the number of N + 1 frames acquired in steps S1-3 to S1-6 (steps S1-11, S1-
12).

In step S1-11, when the calculation of the normalized correlation value Ci is completed for the images of the (N + 1) th frame and the maximum normalized correlation value Cmax is obtained, the lens stage 103 moves to step S1-8. The lens stage 103 is moved to the position where the maximum normalized correlation value Cmax is obtained among S1 to S1-12, and the processing is ended (step S1-
10).

After moving to the position of the lens stage 103 where the maximum normalized correlation value Cmax is obtained in step S1-10, the laser welding machine (not shown) is controlled by a command from the main controller 112. , The LD package 11 and the lens package 12 are laser-welded. 4 and 5 are explanatory diagrams of the operation of the first embodiment of the present invention. 4 shows time on the horizontal axis, FIG. 5 shows time on the horizontal axis, and the position of the lens stage 103 on the vertical axis.

When the image processing program is executed at time t0, the position search range P0 to P1 is set to, for example, 33 msec.
Images are sequentially captured for each c, and frame numbers 0 to
N images are sequentially taken into the frame buffer 121. At time t1, when an image in the position search range is fetched into the frame buffer 121, the position of the lens stage 103 is held at the final search position P1, and then each of the images of frame numbers 0 to N fetched into the frame buffer 121 , A normalized correlation value is calculated based on the template pattern held in the template holding unit 122.

At time t2, when the normalized correlation value Ci is calculated for the images of frame numbers 0 to N, the largest normalized correlation value Cmax among the normalized correlation values Ci of the images of frame numbers 0 to N is detected. I do. The lens stage 103 is moved to the position P5 where the image of the frame number of the detected maximum normalized correlation value Cmax is captured, and the process is completed. FIG.
FIG. 11 shows a relationship between the normalized correlation value and the position search range according to the first embodiment of the present invention.

In FIG. 6, the normalized correlation value C at the search position P1
1. At the search positions P2 and P8, the normalized correlation value C2 (= C
8), normalized correlation values C3 (= C
6), normalized correlation value C4 at search position P4, search position P5
When the normalized correlation value C5 (Cmax) is calculated in (5), the lens stage 103 is moved to the search range P5 where the maximum normalized correlation value C5 (Cmax) is obtained.

In this embodiment, step S1 of FIG.
In steps -7 to S1-12, the normalized correlation value is calculated by performing pattern matching on all the images acquired in the position search range. The slope of the normalized correlation value is detected, and the slope of the normalized correlation value is detected. There is also a method of obtaining the maximum value of the normalized correlation value in accordance with the change of. Here, a method of obtaining the maximum value of the normalized correlation value according to the change in the slope of the normalized correlation value will be described as a second embodiment. Since the configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, description thereof is omitted.

FIG. 7 is a flowchart showing the operation of the image processing unit according to the second embodiment of the present invention. In the figure, the same reference numerals are given to the same processing parts as in FIG. 3, and the description thereof will be omitted. The processing of the present embodiment is different from the processing of the first embodiment in steps S1-8 to S1-8.
The processing in step S1-12 is different. In this embodiment,
In step S1-8, the i-th frame image is subjected to pattern matching, and the normalized correlation value Ci is calculated.
Is 0, that is, whether or not the normalized correlation value C0 of the first image is obtained (step S2-1).

In step S2-1, in the case of the normalized correlation value C0 of the first image, since the image at the previous position does not exist, its inclination is unknown. The value C0 is set to the maximum normalized correlation value Cmax, i = i + 1, and the process returns to step S1-8 to obtain the normalized correlation value of the next image (steps S2-2 and S2-2).
2-3).

After i = 1, the image of the i-th frame is subjected to pattern matching in step S1-8, and the normalized correlation value Ci is calculated. When the normalized correlation value Ci is calculated, the normalized correlation value of the image acquired at the previous position is obtained. Difference ΔCi from Ci-1 (= Ci-Ci-1),
That is, the slope of the normalized correlation value is calculated (step S
2-4). Next, it is determined whether the slope ΔCi of the normalized correlation value calculated in step S2-4 is positive or negative (step S2-
5).

In step S2-5, the gradient Δ of the normalized correlation value
If Ci is positive, that is, ΔCi ≧ 0, there is a possibility that the normalized correlation value of the image at the next position may become the maximum value.
Returning to step S2-2, the normalized correlation value Ci of the image at the current position is set to the maximum normalized correlation value Cmax, and the normalized correlation value of the image at the next position is obtained (step S2-).
3, S1-8).

In step S2-5, when the gradient .DELTA.Ci of the normalized correlation value is negative, that is, when .DELTA.Ci <0, the normalized correlation value Ci-1 of the image at the previous position is smaller than that of the current position. Since it is larger than the normalized correlation value Ci of the image, it can be determined that the normalized correlation value Ci-1 of the image at the previous position is the maximum value. This is because the characteristic of the normalized correlation value Ci with respect to the search position Pi becomes a quadratic function characteristic.

Therefore, the normalized correlation value C of the image at the previous position
i-1 is set to the maximum normalized correlation value Cmax, and pattern matching and normalized correlation value Ci
Is stopped (step S2-7), and the normalized correlation value C
The lens stage 103 is moved to the position of max, and the process ends (step S1-13). 8 and 9 are explanatory diagrams of the operation of the second embodiment of the present invention.

In this embodiment, when reading of the image within the position search range is completed at time t1 in FIG. 9, a normalized correlation value C1 of the search position P1 is calculated as shown in FIG. At this time, since the gradient ΔCi of the normalized correlation value cannot be obtained, first, the normalized correlation value C1 is set to the maximum normalized correlation value C1.
Set to max. Next, the normalized correlation value C at the search position P2
2 is calculated. At this time, since the normalized correlation value C2 is larger than the normalized correlation value C1 at the previous position P1, the slope ΔCi of the normalized correlation value becomes positive, and the normalized correlation value C2 is set to the maximum normalized correlation value Cmax. I do.

Since the slope ΔCi of the normalized correlation value is positive, it can be determined that the normalized correlation value C3 at the next search position P3 may be larger than the normalized correlation value C2.
A normalized correlation value C3 at the next search position P3 is calculated. Next, a normalized correlation value C3 at the search position P3 is calculated. At this time, when the normalized correlation value C3 is larger than the normalized correlation value C2 at the previous position P2, the slope ΔCi of the normalized correlation value becomes positive, The normalized correlation value C3 is set to the maximum normalized correlation value Cmax.

Since the slope ΔCi of the normalized correlation value is positive, it can be determined that the normalized correlation value C4 at the next search position P4 may be larger than the normalized correlation value C3.
A normalized correlation value C4 at the next search position P4 is calculated. Next, the normalized correlation value C4 at the search position P4 is calculated. At this time, when the normalized correlation value C4 is larger than the normalized correlation value C3 at the previous position P3, the slope ΔCi of the normalized correlation value becomes positive, The normalized correlation value C4 is set to the maximum normalized correlation value Cmax.

Since the slope ΔCi of the normalized correlation value is positive, it can be determined that the normalized correlation value C5 at the next search position P5 may be larger than the normalized correlation value C4.
A normalized correlation value C5 at the next search position P5 is calculated. Next, the normalized correlation value C5 at the search position P5 is calculated. At this time, when the normalized correlation value C5 is larger than the normalized correlation value C4 at the previous position P4, the slope ΔCi of the normalized correlation value becomes positive, The normalized correlation value C5 is set to the maximum normalized correlation value Cmax.

Since the slope ΔCi of the normalized correlation value is positive, it can be determined that the normalized correlation value C6 at the next search position P6 may be larger than the normalized correlation value C5.
A normalized correlation value C6 at the next search position P6 is calculated. Next, the normalized correlation value C6 at the search position P6 is calculated. At this time, when the normalized correlation value C6 is smaller than the normalized correlation value C5 at the previous position P5, the slope ΔCi of the normalized correlation value becomes negative, Since the previous normalized correlation value C5 is larger than the current normalized correlation value C6, the previous normalized correlation value C5 is set to the maximum normalized correlation value Cmax.

At this time, the slope ΔC of the normalized correlation value
Since i is negative and the characteristic of the normalized correlation value Ci with respect to the position P is quadratic, the normalized correlation value C7 at the next search position P7 is unlikely to be larger than the normalized correlation value C6. Since the determination can be made, the calculation of the normalized correlation values C7 and C8 at the positions P7 and P8 is stopped thereafter. Therefore, at time t11 in FIG. 9, the pattern matching and the calculation processing of the normalized correlation value are stopped, and the lens stage 103 is moved.

As described above, according to this embodiment, there is no need to perform unnecessary pattern matching and unnecessary normalized correlation value calculation, so that the processing time can be reduced. Note that the first and second
In the embodiment, the normalized correlation value of the image of the (N + 1) th frame is obtained within the preset position search range, and the maximum value is obtained. However, the processing of the first and second embodiments is repeated to narrow down the position search range. , The maximum value can be determined to accurately determine the maximum normalized correlation value.

A method of narrowing the position search range by repeating the processing of the first and second embodiments will be described as a third embodiment. Since the configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, description thereof is omitted. FIG. 10 is a processing flowchart of the image processing unit according to the third embodiment of the present invention. In this embodiment, first, the processing of steps S1-1 to 1-12 shown in FIG. 3 of the first embodiment or steps S1-1 to S1-8 and S2-1 to S2 shown in FIG. 7 of the second embodiment. -7
The maximum normalized correlation value Cmax is obtained by the processing of (step S3-1).

Next, the position Pmax-1 before and after the position Pmax of the maximum normalized correlation value Cmax obtained in step S3-1,
The range of Pmax + 1 is set as the position search range (step S
3-2). Next, in step S3-2, the processing of steps S1-1 to 1-12 shown in FIG. 3 of the first embodiment or FIG. 7 of the second embodiment is performed with the set position search ranges Pmax-1 to Pmax + 1. Steps S1-1 to S1-8, S2-1 to S2 shown in FIG.
The maximum normalized correlation value Cmax is obtained by the process of -7 (step S3-3).

Next, the lens stage 103 is moved to the position of the maximum normalized correlation value Cmax obtained in step S3-3, and the process ends (step S3-4). FIG.
FIG. 11 is a diagram for explaining the operation of the third embodiment of the present invention. In FIG. 11, the horizontal axis indicates the image reading position, and the vertical axis indicates the normalized correlation value Ci. In the same figure, x indicates detection of ancestry, and o indicates fine detection.

First, in step S3-1 in FIG. 10, a relatively wide range of the positions P1-1 to P1-7 is set as a search range as indicated by a mark X in FIG. 11, and an image is read. Pattern matching is performed on the images read at -1 to P1-7, and normalized correlation values C1-1 to C1-7 are calculated. In the position search ranges P1-1 to P1-7 in FIG. 11, the maximum normalized correlation value Cmax1 is the normalized correlation value C1-4 of the image acquired at the position P1-4. Next, positions P1-3 (Pmax-1) to P1-5 (Pmax + 1) before and after the position P1-4 are set as the position search range. Position search range P1-3 (Pmax-1)
The image is read at ~ P1-5 (Pmax + 1) and each position P
2-1-Normalized correlation value C2-1-of the image acquired at P2-7
C2-7 is calculated.

In FIG. 11, the maximum normalized correlation value Cmax2 in the position search ranges P2-1 to P2-7 is the normalized correlation value C2-2 of the image acquired at the position P2-2. This normalized correlation value C2-
2 as the final maximum normalized correlation value Cmax2, the lens stage 103 is moved to a position P2-2 where the maximum normalized correlation value Cmax2 is obtained. As described above, the position search range P1-1
From P1 to P7, the maximum normalized correlation value is Cmax1, but the maximum normalized correlation value Cmax2 larger than the normalized correlation value Cmax1 is obtained from the position search ranges P2-1 to P2-7. Therefore, the lens can be accurately positioned.

In this embodiment, the position search range is narrowed down to one time, but an accurate position can be obtained by repeating the number of times. Further, in the first to third embodiments, for example, as shown in FIG.
In S1-6, the images within the position search range are read, and after all the images are stored in the frame buffer 121, the normalized correlation values Ci are calculated in steps S1-7 to S1-12. By using the CPU, the reading of the image within the position search range in steps S1-2 to S1-6 in FIG. 3 and the normalized correlation value C in steps S1-7 to S1-12 are performed.
The calculation of i may be performed in parallel.

FIG. 12 is an operation explanatory diagram of a modification of the first embodiment of the present invention. FIG. 12A shows the timing of image reading, and FIG. 12B shows the timing of pattern matching and normalized correlation value calculation processing. When reading of the image starts at time t20, pattern matching of the image of the first frame is performed at time t21 when the image of the first frame is stored in the frame buffer 121, as shown in FIG.
Normalized correlation value calculation is performed. The image of the second frame is read into the frame buffer 121 while the pattern matching and the normalized correlation value calculation of the image of the first frame are performed as shown in FIG.

As shown in FIG. 12B, at time t22, when the pattern matching of the image of the first frame and the calculation of the normalized correlation value are completed, the pattern matching of the image of the second frame and the normalization are continued. Correlation value calculation is performed. As shown in FIG. 12, the image reading speed is faster than the pattern matching and the normalized correlation value calculation processing.
, The image reading ends, and the normalized correlation value calculation processing ends at time t24. However, since the normalized correlation value calculation processing is performed during the image reading, the processing is performed in comparison with the case where the normalized correlation value calculation processing is performed after the image reading is completed, for example, as illustrated in FIG. Can be shortened.

Although FIG. 12 illustrates the case where the first embodiment is processed in parallel, it is naturally applicable to the second and third embodiments.

[0071]

As described above, according to the first aspect of the present invention, the position of the optical system with respect to the image is controlled to capture an image in a predetermined position search range, and the captured image and the image By calculating an evaluation value according to the deviation from the image set in advance and detecting the optimum position of the optical system with respect to the image according to the calculated evaluation value, even if the shape of the image is complicated, Since the evaluation value is calculated in accordance with, the position of the image can be detected with certainty, so that the positional relationship of the optical system with respect to the position of the image can be accurately detected.

According to the second aspect, the image of the predetermined position search range is continuously imaged, and the image is held for each frame, so that it is not necessary to repeatedly move and stop the imaging position minutely. Can be performed in a short time, and thus the overall processing time can be shortened. According to the third aspect, by executing the imaging process and the correlation calculation process in parallel, the imaging and the correlation calculation are performed simultaneously, and there is an advantage that the entire processing time can be reduced.

According to the fourth aspect, the position at which the image of the maximum value among the correlation values calculated in the correlation calculation process is taken as the optimum position is determined, so that the image most correlated with the preset image is determined. Since the obtained position can be determined as the optimum position, it has such features that the optimum position can be reliably detected. According to the fifth aspect, the slope of the normalized correlation value is detected, and when the slope of the normalized correlation value is inverted, the correlation value immediately before the inversion is set as the maximum value and the position where the image of the maximum value is captured is determined as the optimum value. As a result, even if all the correlation values do not exist, the maximum value can be detected, so that the calculation of the correlation value can be omitted, so that high-speed processing can be performed.

According to the present invention, a predetermined range around the optimum position determined in the position determination step is set as a position search range, and the imaging step, the correlation calculation step, By executing the position determination step, the position search range can be narrowed down sequentially, and the optimum position can be accurately detected. According to the seventh aspect, the positional relationship of the optical system with respect to the image is controlled, the image of the predetermined position search range is captured by the imaging unit, and the image and the image captured by the evaluation value calculation unit are set in advance. By calculating an evaluation value corresponding to the deviation from the image and detecting the optimum position of the optical system with respect to the image in accordance with the evaluation value calculated by the position determination unit, even if the image has a complicated shape, Since the evaluation value is calculated in accordance with, the position of the image can be detected with certainty, so that the positional relationship of the optical system with respect to the position of the image can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of an image processing unit according to the first embodiment of the present invention.

FIG. 3 is a processing flowchart of an image processing unit according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of an operation of the image processing unit according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of an operation of the image processing unit according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between a normalized correlation value and a position search range according to the first embodiment of the present invention.

FIG. 7 is a processing flowchart of an image processing unit according to a second embodiment of the present invention.

FIG. 8 is an operation explanatory diagram of the second embodiment of the present invention.

FIG. 9 is an operation explanatory diagram of the second embodiment of the present invention.

FIG. 10 is a processing flowchart of an image processing unit according to a third embodiment of the present invention.

FIG. 11 is an operation explanatory diagram of the third embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of a modification of the first embodiment of the present invention.

FIG. 13 is a configuration diagram of a bidirectional optical communication unit.

FIG. 14 is a diagram for explaining a conventional lens position detection method.

FIG. 15 is a diagram for explaining a lens position evaluation method based on luminance dispersion.

[Explanation of symbols]

 Reference Signs List 1 bidirectional optical communication unit 2 optical fiber cable 11 LD package 11a light emitting element 11b light receiving element 11c package 12 lens package 12a lens 12b holder 13 prism unit 13a prism 13b total reflection mirror 13c half mirror 100 automatic lens adjusting device 101 LD stage 102 LD Stage controller 103 Lens stage 104 Lens stage controller 105 Microscope 106 Illumination light source 107 CCD camera 108 Camera stage 109 Camera stage controller 110 Image processing device 111 TV monitor 112 Main controller

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihiko Yabuki 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hitoshi Komoriya 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fujitsu Limited (72) Inventor Tetsuo Hizuka 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited

Claims (7)

[Claims] 1. An automatic position detection method for capturing an image whose positional relationship with an optical system is to be adjusted through the optical system, and detecting a position of the optical system with respect to the image according to a captured result. Controlling the positional relationship of the optical system with respect to an image, an image capturing step of capturing an image in a predetermined position search range, and an image captured in the image capturing step and a predetermined image set in advance according to the image. An evaluation value calculating step of calculating an evaluation value according to the correlation; and a position determining step of detecting an optimum position of the optical system with respect to the image according to the evaluation value calculated in the evaluation value calculating step. Automatic position detection method. 2. The image capturing step according to claim 1, wherein the image of the predetermined position search range is continuously captured.
Automatic position detection method as described. 3. The automatic position detecting method according to claim 1, wherein the imaging step and the evaluation value calculating step are performed in parallel. 4. The method according to claim 1, wherein the position determining step determines a position at which an image having a maximum value among the evaluation values calculated in the evaluation value calculating step is captured as the optimum position. 6. The automatic position detection method according to claim 1. 5. The position determination step detects a slope of the evaluation value calculated in the correlation calculation step, and when the slope of the evaluation value is inverted, sets the evaluation value immediately before the inversion to a maximum value. 4. The automatic position detecting method according to claim 1, wherein a position at which a value image is captured is determined as the optimum value. 6. A position search range setting step of setting a predetermined range around the optimum position determined in the position determination step as a position search range, wherein the position set in the position search range setting step is set. 6. The automatic position detecting method according to claim 1, wherein the image capturing step, the evaluation value calculating step, and the position determining step are performed on a search range. 7. An automatic position detecting device for capturing an image whose positional relationship with an optical system is to be adjusted through the optical system, and detecting a position of the optical system with respect to the image according to a captured result. An image capturing unit that controls a positional relationship of the optical system with respect to an image to capture an image in a predetermined position search range, and an image captured by the image capturing unit and a predetermined image set in advance according to the image. Evaluation value calculation means for calculating an evaluation value according to the correlation; andposition determination means for detecting an optimum position of the optical system with respect to the image according to the evaluation value calculated by the evaluation value calculation means. Automatic position detection device.