JPH04502072A - Alignment system in optical matched filter correlator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Alignment system technology for optical matched filter correlators The present invention relates to a system for adjusting position with high precision, particularly in an optical correlator. Aligner that precisely aligns matched filter arrays used as memory related to the management system. In more detail, multiple hydrographic diagrams in optical correlators a position adjustment system that aligns the 71-chido filter array with respect to the optical lens; , a special m! added when aligning this matched filter array. For I It is related to the target.

Conventional technology For optical correlation systems, see US Pat. The technical contents are disclosed in the Japanese patent application), and the present invention applies to this optical correlation system. There are 7 technologies that have evolved from the position adjustment technology used in the In an optical correlation system, the input image and the recognition results obtained from the optical information stored in the multi-matted filter. At the same time, the input image and external shape information regarding this image are compared.

In the disclosed embodiments, an input image is directed to an optical spatial modulator and spatially modulated. becomes a coherent beam of light. This coherent beam light is generated by multiple holograms. Guided by Ficklens. Multiplex holographic lenses provide higher-order Fourier coefficients This higher-order Fourier coefficient is a spatially modulated coherent The light beam is detected by being Fourier transformed by a plurality of optical element arrays. This way A matted filter array, which is an array of optical elements, is a Fourier transform the beam light.

Each matched filter performs a three-dimensional Fourier transform on the important features of the object. It is composed of A matched filter allows optical correlation signals to pass through. ing. This optical correlation signal is the correlation obtained when the coherent beam light is Fourier transformed. It is a degree-dependent signal. That is, a spatially modulated coherent beam of light passes through the hologram recorded in the above-mentioned matched filter and undergoes a Fourier transformation. After the optical correlation signal passes through this filter, the correlation with the Fourier transform is calculated. Indicates degree.

The inverse Fourier transform lens converts the optical correlation signal that is the output of the matched filter array. This optical correlation signal is then subjected to inverse Fourier transform. The detector is an inverse Fourier of the optical correlation signal. Detect the conversion result. The output signal of this detector is then used to determine information and image recognition information.

This type of optical correlator has the following problems. That is, multiple holograms The Fourier transform performed by the Fick lens is applied to each matched filter. Each matched filter must be aligned properly and Setting with high precision is required. This position adjustment will be referred to as "alignment" from now on. Say.

In a typical matched filter, the axial distance along the two rings (optical axis) and γ( (pitch axis) rotation and β (M-wheel) rotation. These axial distances, pitches and Initial adjustment of rotation and yaw rotation is performed when the optical correlator is installed in a predetermined position.

In such a typical optical correlator, a new matched filter is installed. In case, alignment adjustment for each axis of X-axis, 1st wheel and 0th wheel (roll) required to do so.

U.S. Pat. No. 3,539,260 describes how coherent spatial frequency filters can be automatically Techniques for alignment are disclosed. This technology Using four position reference patterns superimposed along the orthogonal axes of the filter plate It is something to do. These four position reference patterns are sequentially processed by time-sharing processing. Used as a target. In this disclosed patent, one matte There is a limitation on the alignment of the filter, and the There is no equivalent disclosure regarding the alignment relationship for the router array. Moreover, the use of complex multiple holographic lenses was also disclosed. Additionally, the system disclosed in U.S. Pat. No. 814,209 has multiple matte filter array, but the signals output from all matched filters at the same time The technology to use the number has not yet been realized.

Disclosure of invention The invention derives from an input image and optical information stored in multiple 71-tide filters. In addition to comparing the input image and the external shape information regarding this image, Regarding the optical correlators to be compared. And, in such an optical correlator, - Designed to properly align the filter array.

An optical correlator spatially transforms a coherent beam of light used to analyze an input image. and a multiple hologram into which this spatially modulated coherent beam light is incident. It has a graphic lens, Fourier transforms the coherent beam light, and transforms it into a high-order frame. A means to generate Fourier coefficients and three-dimensional Fourier transform of important shapes of objects A spatially modulated coherent beam of light is recorded on a filter. Fourier transform is performed by passing through the hologram, and the correlation with this 7-lier transform is calculated. generating and forming an optical correlation signal indicating the degree of alignment of at least two A target is placed and the alignment information obtained from this target is memorized. A mated filter having an optical storage element and an output of this mated filter array. An inverse Fourier transformation process that receives an optical correlation signal and performs an inverse Fourier transform on this optical correlation signal. A converting lens and multiple detectors that detect the optical correlation output of this inverse Fourier transform lens. one detector outputs a signal representing the optical correlation signal and the other detector outputs a signal representing the optical correlation signal. A tester that outputs a signal representing the inverse Fourier transform result from each alignment target. output means and an optical memory element based on the signals from each alignment target. and an alignment system for alignment.

More specifically, as shown in the example, the mated filter array may be an nxn matrix or and two alignment members placed on the diagonal elements of this nxn matrix. and target. Each alignment target has sharp edges Forms a rectangular shape.

In the example shown below, in a typical matched filter of an optical correlator, two rings are used. (optical axis), γ (pitch) rotation and β (!l-) rotation. II! The case of I will be explained. Note that these axial distances, pitch and yaw Initial adjustment of rotation is performed while the optical correlator is installed in a predetermined position. If a new matched filter is installed, the X-axis, 1st wheel and 0th wheel (low alignment is required for each axis of the That is, this implementation According to the example alignment system, digital control is provided, and this control is The above-mentioned X-axis position, y-axis position, and θ-axis angle are determined by a microprocessor, Alignment is performed by a digital sequencer. This alignment is repeated repeatedly until the correct value is obtained.

Brief description of the drawing Figure 1 shows an overview of the optical correlation system. Fig. The lower middle part is a multiple holographic lens (MHL) that performs multiple Fourier transform on the input image. ) and a diagram showing the configuration of a multiple matched filter.

FIG. 2 shows a multi-matted frame to which the alignment stem according to the present invention is applied. The following section outlines an optical correlator consisting of a filter array and multiple holographic lenses. sm is when there is misalignment on the X axis, 1st wheel and 0th wheel. FIG. 2 is an enlarged view of a Fourier transform pattern projected onto a Tido filter.

Figure 4 shows that when there is misalignment only regarding the 0 wheel, - An enlarged view of the Fourier transform pattern projected onto the filter.

The 5th WJ has a matched filter of 8 rows and 3 columns, and array positions (0, 1) and (n +1. mattified fill in which two alignment targets of n) are arranged. FIG.

FIG. 6 is provided corresponding to the matched filter array shown in FIG. 1 is a diagram showing a multiple holographic lens (MHL); FIG.

71st! l is multiplexed with the mated filter array illustrated in FIGS. 5 and 6. The alignment relationship when operating in combination with a holographic lens FIG.

Figure 8 shows the matched filter application for multiple holographic lensing (MHL). It is a figure showing an example of the system which rotates a ray around one ring and adjusts an angle.

Figure 9 is an example of an alignment target temporarily provided for a matched filter. FIG.

Figure 1θ shows the Fourier transform results for a rectangular aperture alignment target. It is a figure showing energy distribution.

Figure 11 shows the alignment mechanism used in the alignment system according to the present invention. 3 is a graph showing the detection sensitivity of a target target.

Figure 12 shows the configuration of the stepper motor used in the 7 linement system. FIG.

Calculation 13■ explains the alignment operation performed for each of the X-axis, 7 wheels, and θ-axis. This is a flowchart for

detailed description This invention is disclosed in U.S. Pat. No. 841,209 issued on February 27, 985 Regarding the technology disclosed in the specification, in particular, multiple hydrographic lenses (MHL) and Regarding a system using a multiple mated filter array (MMF) It is.

In the above-mentioned earlier application, 'C' is often concerned with the concept of the present invention, the number of elements used, etc. However, below, first, the gist of the present invention will be described.

A holographic lens (ML) formed from film etc. has an interference pattern. recorded. This interference pattern is defined as a pair of The object is irradiated with a fimated beam of light, and the photo obtained by this irradiation is It is a logram image. A beam is placed on a hologram lens that records these interference patterns. When irradiated with beam light, the image of the object recorded at the focal point of this lens is reproduced.

When an interference pattern is repeatedly recorded on a holographic lens, a continuous hologram is created. This results in a multiple holographic lens (MHL) in which the Lamb image is recorded.

The optical correlator is a multiplex hologram that Fourier transforms spatially modulated laser beam light. Used to offset focal length and focal position in optical lens arrays. The holographic lens used focuses the laser beam irradiated onto the object. Multi-holographic lens performs multiple 7-lier transforms simultaneously. . This multiplexed holographic lens is typically compatible with matched filter arrays. It will be established.

FIG. 1 is a diagram showing an outline of an optical correlation system according to the present invention. This figure smells The lens lO is then irradiated with the spatially modulated collimated beam light 12. this The climate beam light 12 passes through an input image or a recorded image 14 of the object. Spatial modulation is performed by This lens lO has a field placed at its focal position. A Fourier f-transformed image is formed on the lumen 16. Here, the Fourier transform image and the collimated When the light beams interfere with each other, an interference pattern is formed. This interference pattern is transform hologram, or convert the input object into a matte filter, which is an optical spatial filter. called "filter". Matched filters in optical correlation systems are It is used to extract or pass power images. These filters allow The optical signal that has passed is subjected to Fourier transformation again. And this produces An optical correlation signal is detected.

At the bottom of the figure, multiple holography and cleansing (hereinafter referred to as MHT- ) 19 is illustrated. This MHL+, 9 is a spatially modulated beam light is Fourier transformed, thereby forming a Fourier transformed image of the object on the focal plane. Ko The remated reference beam 18 is connected to a film (or 77° filter plate). )] The Fourier transform hologram written on G is the intervene.

MHL 19 has *M holographic lenses arranged to form an array, each with 7 A Fourier transform is performed on each ray. The matt filter (MF) is , MHL19 are arranged corresponding to each focal point position. matt filter (MP) ) constitutes an optical memory that serves as an optical correlator. 77 Vud Filter ( MF) is a target formed by many targets or multiple surfaces, or , can be configured according to a combination of these. Actually, these The 71-chip filter array has its position aligned for proper operation. Turn on.

The above-mentioned matt filter, t+':, is the 7 fugid filter that covers the array. The multi-matched filter can also be realized by computer processing. Wear.

Matsushido Fu, C filter realized by combinatorial processing is actually ・Unlike a filter, there is no angle based on the misalignment of its placement. .

Figure 2 shows the configuration of an optical correlator to which the alignment system according to the present invention is applied. FIG. This alignment system consists of multiple holograms mentioned in 1 above. This method aligns multiple 71-chid filter arrays with respect to the cleanser. Ru. An object 20 is arranged at the input position of the optical correlator, and this object 200)a is The light is projected onto a spatial light modulator (SLM) 24 through an object lens 22 . beyond this space The beam 11 [(SLM) 24 is directed by a beam splitter 30 and a reflector 28. The input image is optically modulated by the attached laser beam 26. light modulated The laser beam light is Fourier transformed by the multiple holographic lens 32. Ru.

The laser beam light subjected to this Fourier transformation is then passed through a matted filter 3. 4 arrays. The inverse Fourier transform lens 36 is The optical signal output from the filter array 34 is inversely Fourier transformed. The Rie transform result is input to the detection element array 38. The detection element array 38 The detection signal is supplied to the processing circuit 40.

In this way, the matched filter uses the input position of the input image, the image size, and the expected A Fourier transform hologram image is formed based on the sensitivity corresponding to the viewing angle. This sensitivity The related parameters are the angle at which the object is viewed and its range, so , it becomes possible to predict. The detector uses a detection element with the desired resolution. I can stay.

In a mated filter configuration, the holographic visible edge is Optimized by wave number. Here, this specific spatial frequency is Sensitivity to size, or sensitivity to viewing angle of an object, or both This is a spatial frequency that satisfies both sensitivities. However, the requirements of both Since this is sometimes difficult to satisfy, the optical correlator requires mutually independent matted This is why a filter is used.

A matched filter is described by the Fourier transform of the input image or target. can do. Here, the input image is: FRography 1 reference beam incidence angle and It is represented by a stem constant S. This /stem constant S is defined as follows. sand Well, Sm (gF) -' (cycles/mm/mm) where g (mm) and F (mm) are the structural wavelength of the matched filter and the wavelength to be Fourier transformed, respectively. focal length of the lens. The smaller this constant S is, the easier it is to control parameter sensitivity. Therefore, problems related to one-position adjustment can be easily solved.

Spatial frequency bandwidth is the next most important factor in mated filters. Can be mentioned. Matched filters can be optimized at the desired frequency. However, the degree of object discrimination depends on the fineness of the object, that is, the height of the spatial frequency. Exists. This frequency requirement takes into account the size, location and shape of the object. Ru.

The purpose of the present invention is to provide a multi-matched filter (hereinafter referred to as (This is called MMF) automatically aligns special targets added to the array. It's about doing. The output of this target is Used for stepper motor control. Multiple holographic lens (M HL) The advantage of this is that many lenses can be arranged in one lens. This lens is The larger one can be configured with 10 rows and 10 columns (100 lenses). However, typical arrays consist of 3 rows and 3 columns, 5 rows and 5 columns, or 6 rows and 6 columns. It is. The larger the MMF array, the more matted fills each correspond to. Alignment problems are noticeable because the It will be done.

It is especially difficult to reinstall matted filters once the installation position is fixed at a given angle. When placed, the appropriate X-axis and position along the alignment is no longer guaranteed. Upper leftmost arrangement in MMF array The position and the array position of the lower right end, which is the diagonal element position, are properly aligned. Aligned. Typically, the larger the array, the greater the distance between its diagonal element locations. The distance will be longer. In this way, if you look at it intuitively, the same position on the X and y axes and the rotation on the θ axis It is understood that alignment sensitivity with respect to rotation increases as the array becomes larger. be done.

System 3 diagram shows the match when there is an alignment error regarding the X axis, X axis, and θ axis. FIG. 3 is an enlarged view showing the shape of a de-filter, that is, a Fourier transformation pattern.

The matched filter shown in this figure is formed from a dot pattern array. .

In other words, the pattern shown by this solid line is transmitted through one of the MHL array lenses. This is a laser pattern formed on a target. The purpose of this invention is to The objective is to align patterns with respect to the X axis, the X axis, and the θ axis.

The spatial frequency of the mated filter (MF) is directed outward from the center of the pattern. It was once measured in the unit rcycle/mmJ, and the How to choose the appropriate frequency, i.e. bypass MF or The question arises as to whether or not he should use Cubas as a midfielder. This is based on system-specific characteristics and This is done taking into account both the unique characteristics of the target and the widest range of coverage possible. Select the spatial frequency of the range. Such a choice typically The signal-to-noise ratio with the background is taken into account.

Figure 4 shows the matched filter when there is misalignment only on the θ axis. It is an enlarged view showing a pattern. In this figure, the spatial frequency corresponds to rOJ Pattern centers 42 are vertically and horizontally aligned.

In the situation shown in Figure 4, offsets in the X-wheel and Y-axis directions are removed. The case is shown in which the error around the θ axis is corrected. Spatial frequency band weight The degree corresponds to the position of the pattern in this matched filter.

The MMF 44 shown in FIG. 5 consists of a matched filter arranged in 3 rows and 3 columns. like this In MMF44, targets are arranged in the 1st row and 1st column and the 3rd row and 3rd column. . Preferably, special targets are added to these targets. That is, this According to the invention, a special target is provided to perform alignment with high precision. Ru. This special target is placed on both sides of the play in 3 rows and 3 columns, and these two An error representing the alignment error from the difference between the outputs obtained from two special targets. A signal is generated. Figure 5 shows the structure of the multiple matched filter (MMF) plate 44. FIG. The MMF 44 shown in this figure is a matched filter with 3 rows and 3 columns. a target array and two special targets 46 provided on both sides of this array. . Multi-olographic lenses (MHL) meet the requirements of MMF due to these configurations. The configuration of MHL48 in this case is shown in Figure 6. show. The MHL48 shown in this figure corresponds to the special target 46 mentioned above. An alignment lens 50 is included.

FIG. 7 shows the multiple holographic lens 48 shown in FIG. 6 and this lens 48. When arranged in combination with a correspondingly arranged multiple matched filter array 44. FIG. 3 is a diagram showing an alignment relationship when Laser light that is collimated and enters 51 is modulated with input images superimposed at the center. At this time, the outer part is a special target. used to modulate the cut. The aperture plate 52 is positioned at the center of the beam light. a central aperture 54 located on the outside of the central aperture 54 and a central aperture 54 located on the outside of the central aperture 54; and an outer opening 55 provided therein. This outer opening 55 can be used as a special target. The beam light that irradiates the special target and the match The light beam is separated from the light beam that illuminates the filter array. MHL4g is MMF The plate 58 is provided with a predetermined offset angle. MHL4B and MMF 44 generates 281 types of output formats. First of all, MMF4 A matched filter array of 3 rows and 3 columns arranged on 4, that is, 9 optical lenses. Nine beams of light 56 are incident on the harpoon. Second, MMF44's special target This is the output signal 58 of the cut.

The second lens 60 disposed after the MMF 44 has a matted filter array. A second Fourier transform is applied to the beam light that has passed therethrough. Similar to this second lens 60 The two lenses 62 focus the alignment beam light incident on each lens. rie conversion. The alignment target beam photodetector 64 detects the optical correlation signal. and compare them to generate a differential signal. This differential signal is This signal is used as a drive control signal for the stepper motor that performs pitch correction. This invention Then, according to the flowchart shown in Fig. 13, the Alignment errors that occur are corrected by a computer or controller.

Figure 8 shows multiple matched filter arrays for multiple holographic lenses. The angle of 7 lines Im! ! FIG. 1 is a diagram showing an example of a system. In this diagram, Stepper motor 66 rotationally drives worm gear 68 . This worm gear 68 When the MMF 44 is rotationally driven, the rotation gear 70 provided on the outer periphery of the MMF 44 is rotated.

This causes the MMF 44 to rotate. Figure 912 shows the detector 64 and this step described above. An interface is inserted between the stepper motor 66 and controls the stepper motor 66. FIG. 2 is a block diagram showing the configuration of a base circuit, the details of which will be described later.

A unique alignment device designed for optical correlators is disclosed in US Patent Application No. 6 758, PI-(15086)), and this alignment equipment is It is suitable for use in the present invention. More specifically, as disclosed in the above specification For alignment equipment for optical correlators, at least roll rotation around the θ axis is required. By adjusting the angle and two positions in the X-ring and Y-axis directions, multiple holography, cleansing , multiple matched filters can be aligned respectively.

A plurality of special targets 46 are used in this invention. Generally, this The target has a rectangular shape to form sharp edges. This ingredient As shown in FIG. 9, the black pack ground 74 has a square opening. 72 is formed. With such an aperture shape, the energy along the orthogonal axes is The distribution of energy is similar.

Figure 10 shows the Fourier transform due to the square aperture formed by the 77-tide filter. FIG. As shown in this figure, the larger the aperture, the more The turns become closer together. The part that is energized from the central axis has a higher spatial frequency. represent. For aligned targets, the slope of the output signal is large and the rotation A high spatial frequency is required, which results in less signal variation. In general, Matsushido The higher the spatial frequency of a filter, the sharper its output signal. Also, before Special targets provided at array positions (0,0) and (4,4) in the MMF described above. The position of the target or the rotation angle about the center of this MMF is given by the following equation. available. That is, Δ, l bulk C, Nρd Here, ρ is the rotation angle, and d is the arrangement interval of the array. As you can see from this formula, When the rotation angle ρ is small and the matrix size increases, the array spacing d increases accordingly. increases, so Δ1 decreases. Thus, larger arrays result in increased sensitivity. As a result, special targets in MMF have higher spatial Not only is a high frequency required, but also highly accurate alignment is required.

Small directional differences between the two alignment targets become important. 1st The characteristics shown by the solid line in Figure 1 are the sensitivity to the angle of the two special targets. represents. The angle sensitivity of these two special targets is This is an output difference based on the rotation of the MMF in which the tip is disposed. In this figure, θ is MF It represents the rotation angle of the plate, and the characteristic of the detector corresponding to this θ is shown as a curve. There is. Further, A in the figure is the distance when the characteristic curve is projected. Here, especially important The important point is that each detection signal is the same, that is, there is no difference between them, and there is no error. The reason is that the number is used. However, one alignment target After 6 rotations, a difference of δ occurs between the two response angles. B in the figure is indicated by a solid line. The intersection between the characteristic curve indicated by ) represents the distance. The curve shown by this broken line is the detector characteristic when the above 6 rotations are made. represents. Based on this relationship, if we take the difference between the output signals of the two detectors, we get , lit! corresponding to the rotational error of the MP plate! A signal will be formed.

Figure 12 shows the configuration of an alignment g adjustment system using a stepper motor. It is a block diagram. Detector arranged for two alignment targets The outputs of 64 are each amplified by two preamplifiers 74. And these The output signal of preamplifier 74 is differentially amplified by differential amplifier 76 . this difference As explained in FIG. 11, the output of the dynamic amplifier 76 depends on the rotation angle of the MF plate. corresponding information, and such output is supplied to modulation circuit 78. Modulation circuit 78 generates a pulse signal that drives the stepper motor 66 to rotate. This pulse signal The stepper motor 66 can be rotated in the direction shown in Figure 1E8, that is, clockwise or rotate counterclockwise. In addition, the change @978 shown in this figure, stepper motor 6 6. What type of power supply 80, etc., can be used as long as it is applicable to this optical correlator? Also good.

As a typical detector 64, an SGD-100gj1 detector manufactured by EGG is used. It will be done. This detector performs best when placed in front of the focal point, but in practice In some cases, it is provided at the focal point of the input lens. The sensitivity of a detector is determined by Since the average value is intertwined, minute changes due to defocus will affect the sensitivity. No. Changes in the characteristics of individual detectors are equalized by a preamplifier 74. Ma In addition, a difference is generated between the output signals of these preamplifiers 74 by a differential amplifier 76. This becomes a control signal and is supplied to modulation 874. Therefore, baraclough High-precision MM can be achieved by selecting the gear 68 with no chisels and the stepper motor 66 with uniform steps. It becomes possible to perform F alignment control.

FIG. 13 shows the position m! with respect to the X wheel and the y-axis direction. Alignment l1 including F 2 is a flowchart showing the operation when vl is performed under computer control. . displacement in the y-axis direction until the original output reaches its maximum value. Also, due to the rotation of the θ axis, It goes without saying that various aspects may be adopted based on the gist of the present invention. not.

1H FIG.3 FIG.4 FIG.5 FIG.7 FIG. 11 FIG. 12

Claims (9)

[Claims] (1) Matched filter in which external shape information and recognition information regarding the input image are recorded an array of matched filters; and means for properly positioning the matched filter array; In an optical correlator that optically compares each piece of information with an input image, (a) the input image is analyzed; means for spatially modulating a coherent beam of light used for (b) Multiple holography that allows this spatially modulated coherent beam to enter It has a cleansing lens, Fourier transforms the coherent beam light, and converts the coherent beam into a higher-order Fourier coefficient. a means of generating multiple numbers; (c) configured to three-dimensionally Fourier transform important shapes of the object; A coherent beam of light that has been modulated is passed through a hologram recorded on a filter. An optical correlation signal that shows the degree of correlation with this Fourier transform is and at least two alignment targets are arranged, and this A camera with an optical storage element that stores alignment information obtained from the target. filter, and (d) Receive the optical correlation signal that is the output of this matched filter array, and (e) an inverse Fourier transform lens that performs an inverse Fourier transform on the signal; and (e) this inverse Fourier transform lens. a plurality of detectors for detecting the optical correlation output of the lens, at least one detector detecting the optical correlation output of the lens; Outputs a signal representing the correlated signal, and the other detectors detection means for outputting a signal representing an inverse Fourier transform result; (f) The position of the optical storage element based on the signals from each alignment target. an alignment means to align the An optical correlator comprising: (2) The matched filter array has an array of n rows and n columns. Includes at least two alignment targets located outside each element location. The optical correlator according to claim 1, further comprising: an optical correlator. (3) The alignment target is formed in a rectangular shape with sharp edges. The optical correlator according to claim 2, characterized in that: (4) The alignment means adjusts the angle around the θ-axis and the position in the x-axis direction. and a position adjustment in the y-axis direction. . (5) The matched filter array has an array of n rows and n columns. comprising at least two alignment targets disposed at the element location; The optical correlator according to claim 1, characterized in that: (6) The alignment target is formed in a rectangular shape with sharp edges. The optical correlator according to claim 5, characterized in that: (7) The alignment means adjusts the angle around the θ-axis and the position in the x-axis direction. and a position adjustment in the y-axis direction. . (8) The alignment target is formed in a rectangular shape with sharp edges. The optical correlator according to claim 1, characterized in that: (9) The alignment handle is for corner adjustment around the θ-axis and position adjustment in the x-axis direction. and a position adjustment in the y-axis direction. .