JP2010261810A - Wavefront sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavefront sensor which performs association processing between the coordinates of a light converging point and an individual lenslet at high speed and easily and reduces costs. <P>SOLUTION: A coordinate axis array generation means 102 sorts the two-dimensional coordinates of light converging points to generate a coordinates value array. A differential value calculation means 103 calculates the difference between two successive elements for the coordinates value array. An array number detection means 104 calculates the total number of elements exceeding a threshold. An associating means 105 determines the association relationship between the two-dimensional coordinates group and the individual lenslet 5 on the basis of the two-dimensional coordinates group and the array number detected by the array number detection means 104. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a Shack-Hartmann wavefront sensor for detecting wavefront distortion of a light wave, and more particularly to signal processing thereof.

  The Shack-Hartmann wavefront sensor forms an image of a light wave by a lenslet array in which a large number of small lenses (lenslets) are arranged in a lattice pattern, and measures the wavefront distribution from the image pattern. In the signal processing of the device, it is necessary to identify which lenslet has caused each of the many imaging points. Hereinafter, this process is referred to as an association process. As a method for implementing the association processing, a method is typically used in which a processing table is provided that associates a specific lenslet with a specific area on an image in a one-to-one correspondence by a prior operation. In this method, it is necessary to provide a precondition that an arbitrary lenslet should not enter an image point into a specific area that does not correspond to itself. This precondition limits the dynamic range of wavefront distortion that can be measured. For example, Patent Document 1 discloses a method for improving the dynamic range by changing the optical magnification using a drive mechanism. Patent Document 2 discloses a method of improving dynamic range by providing two sets of lenslet arrays having different magnifications.

JP-T-2001-524661 JP 2004-113405 A

Since the conventional wavefront sensor is configured as described above, it is possible to measure the wavefront with a predetermined dynamic range. However, there are the following problems.
First, it is necessary to have a processing table that associates a specific lenslet with a specific area on an image in a one-to-one correspondence in advance, but complicated processing is necessary to create this processing table. In some cases, it requires human judgment and takes time and effort. Therefore, for example, in the operation of exchanging the lenslet array with a different specification by a user who is not familiar with the apparatus, there is a problem that the convenience is impaired.
Secondly, it was necessary to add hardware for improving the dynamic range. However, if the association process can be performed without using a processing table, it is an unnecessary component, that is, the size and weight of the apparatus are increased. There has been a problem of increasing the cost, increasing the cost, and increasing the measurement time.

  The present invention has been made to solve the above-described problems, and can perform the process of associating the coordinates of the condensing points with the individual lenslets at high speed and at a low cost. It is an object to obtain a wavefront sensor capable of performing

  The wavefront sensor according to the present invention images a lenslet array that generates a large number of condensing point patterns according to the wavefront shape of an incident light wave, and images a large number of condensing point patterns formed by the lenslet array. A wavefront sensor comprising: a two-dimensional detector for converting to a wavefront; and a calculation device for calculating and outputting a wavefront shape of a light wave or a feature quantity corresponding to the wavefront shape from an image signal of the two-dimensional detector. In the two-axis orthogonal coordinate system defined in (2), the two-dimensional coordinate group extraction means for calculating the two-dimensional coordinate group of each focal point, and the coordinates of the two-dimensional coordinate group on the first and second axes of the orthogonal coordinate system A coordinate axis array generating unit that extracts values and sorts them according to the magnitude relationship, and generates a coordinate value array; and a difference value calculating unit that calculates a difference between two consecutive elements for the coordinate value array by the coordinate axis array generating unit; For the difference between two consecutive elements by the difference value calculation means, the array number detection means for calculating the total number of elements exceeding the threshold, the two-dimensional coordinate group extracted by the two-dimensional coordinate group extraction means, and the number of arrays detection Corresponding means for determining a correspondence relationship between the two-dimensional coordinate group and each lenslet based on the number of arrangements of the first axis and the second axis detected by the means.

  The wavefront sensor according to the present invention sorts the two-dimensional coordinates of the focal points to generate a coordinate value array, compares the difference value of two consecutive elements of this coordinate axis array with a threshold value, and exceeds the threshold value Since the correspondence between the two-dimensional coordinate group and the lenslet is determined based on the total number of elements, it is possible to quickly and easily perform the process of associating the focal point coordinates with the individual lenslets. Cost reduction can be achieved.

It is a block diagram which shows the wavefront sensor of Embodiment 1 of this invention. It is explanatory drawing which shows the condensing point pattern image in the wavefront sensor of Embodiment 1 of this invention. It is explanatory drawing which shows typically the process table in the wavefront sensor of Embodiment 1 of this invention. It is a flowchart which shows the signal processing content in the wavefront sensor of Embodiment 1 of this invention. It is explanatory drawing which shows the processing content of the arrangement | sequence number detection means in the wavefront sensor of Embodiment 1 of this invention. It is explanatory drawing which shows the process table for the matching process in the wavefront sensor of Embodiment 1 of this invention. It is a flowchart which shows the signal processing content in the wavefront sensor of Embodiment 3 of this invention. It is a block diagram of the arithmetic unit in the wavefront sensor of Embodiment 4 of this invention. It is explanatory drawing which shows an example of the condensing point pattern made into the process target by the wavefront sensor of Embodiment 4 of this invention. It is explanatory drawing of the matching process in the wavefront sensor of Embodiment 4 of this invention.

Embodiment 1 FIG.
1 is a block diagram showing a wavefront sensor according to Embodiment 1 of the present invention.
The wavefront sensor shown in FIG. 1 has a simplified optical system, and includes an aperture mask 1, a lenslet array 2, and a CCD (Charge Coupled Device) 3. Further, in the figure, a partial light wave 4 shows a part of the measurement target light wave, and a lenslet 5 shows an enlarged arbitrary lenslet on which the partial light wave 4 is incident. A condensing spot 6 indicates a condensing point generated on the CCD 3 by the lenslet 5. The arithmetic device 100 is realized using a computer, and includes a two-dimensional coordinate group extraction unit 101, a coordinate axis array generation unit 102, a difference value calculation unit 103, an array number detection unit 104, and an association unit 105.

  The aperture mask 1 schematically represents that a part of light is blocked in the optical system. In FIG. 1, there is a typical reflection telescope, that is, shielding by a support mechanism of the secondary mirror and the secondary mirror. Simulates a circular opening. The lenslet array 2 is a lenslet array in which lenslets 5 having square openings are arranged in a square lattice pattern (at equal intervals). In the figure, in order to make it easy to understand the correspondence between the partial light wave 4, the lenslet 5 and the focused spot 6, only one of each is shown. All the lenslets corresponding to the unit generate one condensing point on the CCD 3. The lenslet 5 is not limited to a square opening and may have any opening shape. Further, the pattern in which the lenslets 5 are arranged in the lenslet array 2 may be a rectangular lattice having different aspect ratios. The CCD 3 constitutes a two-dimensional detector, but the two-dimensional detector may be other than the CCD.

  The computing device 100 is a device that computes and outputs a wavefront shape of a light wave or a feature amount corresponding to the wavefront shape from an output signal of the CCD 3. The two-dimensional coordinate group extraction unit 101 is a unit that calculates a two-dimensional coordinate group of each focal point in a two-axis orthogonal coordinate system defined on the image. The coordinate axis array generation means 102 is a means for generating a coordinate value array by extracting the coordinate values of the two-dimensional coordinate group on the first axis and the second axis of the orthogonal coordinate system and sorting the coordinate values. The difference value calculation unit 103 is a unit that calculates a difference between two consecutive elements in the coordinate value array by the coordinate axis array generation unit 102. The array number detection means 104 is a means for detecting the total number of elements that exceed a threshold with respect to the difference between two consecutive elements by the difference value calculation means 103. The associating means 105 is based on the two-dimensional coordinate group extracted by the two-dimensional coordinate group extracting means 101 and the number of arrangements of the first axis and the second axis detected by the arrangement number detecting means 104. This is a means for determining the correspondence with each lenslet 5.

  The two-dimensional coordinate group extraction unit 101 to the association unit 105 are configured by software corresponding to each function and hardware such as a CPU and a memory for executing the software. Or you may comprise these two-dimensional coordinate group extraction means 101-association means 105 with exclusive hardware.

Next, association processing in the wavefront sensor configured as described above will be described.
FIG. 2 is an example of a condensing point pattern image captured by the CCD 3. The virtual frame 3 a indicates an area corresponding to the imaging area of the CCD 3, and the condensing point pattern 8 of the image 7 is a pattern of the condensing spot 6. The image 7 is reversed in black and white for convenience of explanation.

FIG. 3 is an explanatory diagram schematically showing a processing table used for the wavefront sensor association processing. In FIG. 3, the detection area 9 in the virtual frame 3 a indicates an area associated with the lenslet 5, the index 10 h is the horizontal index of the detection area 9, and the index 10 v is the vertical index of the detection area 9. is there.
Here, the detection areas 9 referred to by the indexes 10 h and 10 v are associated with the individual lenslets 5 by a prior operation, and the coordinate points existing inside the detection areas 9 are generated by the corresponding lenslets 5. Correspondence processing is performed based on the determination that it is a thing.

  Without knowing the distance between adjacent lenslets 5 in the lenslet array 2, if there is no missing focal point, the lenslet distance is estimated from the focal point pattern 8, the detection area 9 is defined, and the indices 10 h and 10 v are assigned. The process to do is relatively easy. According to the first embodiment, a condensing point defect due to the aperture mask 1 exists, and for which index reference detection region 9 the condensing point defect occurs without knowing prior information as shown in FIG. A signal processing algorithm for generating the processing table of FIG. 3 from the light spot pattern is provided.

First, preconditions will be described. (1) The vertical and horizontal directions of the lattice arrangement in the lenslet array 2 coincide with the horizontal and vertical directions of the image.
(2) Defocus and tilt are dominant in wavefront distortion, and astigmatism and third-order or higher wavefront aberration are relatively small.

FIG. 4 is a flowchart showing signal processing contents of the arithmetic device 100 in the wavefront sensor according to the first embodiment.
In the figure, steps ST1 to ST6 are calculation steps, steps ST2a, ST2b and ST2c are sub-calculation steps of calculation step ST2, and steps ST3a, ST3b and ST3c are sub-calculation steps of calculation step ST3. The calculation step ST1 is executed by the two-dimensional coordinate group extraction means 101. Hereinafter, the sub calculation step ST2a is the coordinate axis array generation means 102, the sub calculation step ST2b is the difference value calculation means 103, and the sub calculation step ST2c is the number of arrays. This is executed by the detecting means 104. The calculation steps ST4 to ST6 are executed by the association unit 105.

Hereinafter, the processing content of each calculation step in FIG. 4 will be described in detail.
In the calculation step ST1, the two-dimensional coordinate group extraction unit 101 extracts the two-dimensional coordinates of all the focused spots 6 from the image signal in which the focused spot pattern 8 is recorded. Here, the two-dimensional coordinates are coordinates on an orthogonal coordinate system with the X axis in the horizontal direction and the Y axis in the vertical direction. In the example of FIG. 2, since there are 45 condensing points, 45 X and Y coordinate values are generated as a result of the calculation in the calculation step ST1. Here, a general case will be described in which N (N: integer of 4 or more) X, Y coordinate values are detected.

Next, the calculation step ST2 will be described. In calculation step ST2a, which is a sub calculation step, the coordinate axis array generation unit 102 sorts the N X coordinate values in ascending order and stores them in an array having N elements. Hereinafter, the elements of the array are referred to by a variable Xi with an index i (i = 0 to N-1).
Next, in the calculation step ST2b, the difference value calculation means 103 calculates the difference between adjacent elements of the array Xi and stores it in a new array DXi (i = 0 to N-2). Specifically, according to the following formula (1).
DXi = X (i + 1) -Xi (1)

  Next, the processing of the calculation step ST2c by the arrangement number detection means 104 will be described with reference to the drawings. FIG. 5 is an explanatory diagram for explaining the processing content of the calculation step ST2c. In the figure, an array DXi (20) indicates an array plotted with an index i on the horizontal axis, and a threshold Th (21) is a threshold defined by a program or a user. In the calculation step 2c, the magnitude relation between all DXi and the threshold value Th is compared, and the number of elements larger than the threshold value Th is extracted. In FIG. 5, eight elements are extracted by this process. As shown in the figure, when the index i is sequentially traced from 0 to refer to DXi, if the element is extracted, it can be determined that the index 10h has been incremented. Therefore, it can be determined that the number obtained by adding 1 to the number of increments is the size H of the processing table of the index 10h.

  The reason why this discrimination criterion is effective can be explained by the preconditions (1) and (2) described above. With this precondition, the X coordinates (X0, X1, X2) of the three points belonging to the same index 10h, for example, “A” are substantially equal, and therefore the difference (DX0, DX1) between these elements is close to zero. However, the difference (DX2) between the coordinates (X2) belonging to the index “A” and the coordinates (X3) belonging to the index “B” is much larger than the inter-element difference. Therefore, it is possible to easily detect an inter-element difference across indexes using an appropriate threshold value Th. As described above, the size H of the index 10h can be detected.

  In calculation step ST3, an algorithm equivalent to that described in the description of calculation step ST2 is applied to the Y coordinate, and the size V of the index 10v is detected.

  In calculation step ST4, the association means 105 defines a processing table for association processing of array size H × V on the image data. FIG. 6 is an explanatory diagram of the processing table defined in the calculation step ST4. In FIG. 6, 30x is the minimum value X0 of the X coordinate, 31x is the maximum value X (N-1) of the X coordinate, 30y is the minimum value Y0 of the Y coordinate, 31y is the maximum value Y (N-1) of the Y coordinate, Reference numeral 32 denotes a detection area. The detection area 32 which is one element of this processing table plays a role equivalent to that of the detection area 9 in FIG. 3 and is a rectangular partial image area referred to by the index 10h and the index 10v. The definition method of the position and size of the processing table is simply determined by the following method.

As a representative, how to obtain the size and position regarding the X coordinate will be described. In this process, all the detection areas 32 have the same size and are arranged at the same position. First, the difference (X (N-1) -X0) between the maximum value 31x and the minimum value 30x of the X coordinate is divided by the number obtained by subtracting 1 from the number of elements (H-1), and Width. Second, the centers of the detection areas at the left and right ends are set equal to the maximum value 31x (X (N-1)) of the X coordinate and the minimum value 30x (X0). Thirdly, the centers of the remaining detection areas are arranged at equal intervals with reference to the processing table elements at both ends.
Further, the position and size regarding the Y coordinate of the detection area 32 are similarly determined.

  In calculation step ST5, association processing is performed using the detection region 32. Specifically, N two-dimensional coordinate points are stored in a two-dimensional array referenced by indexes 10h and 10v.

In the calculation step ST6, the temporarily determined detection area 32 is corrected. The correction items and contents are the following three points.
(1) Replace the center of the detection area 32 with the corresponding two-dimensional coordinate point.
(2) An invalid flag is attached to the detection area 32 in which the corresponding two-dimensional coordinate point is not found.
(3) If two adjacent detection areas 32 are both valid, the size is corrected so that the boundary of the detection area 32 is in the middle.

Since the wavefront sensor according to the first embodiment is configured as described above, the following effects can be obtained.
First, it is possible to automatically generate a processing table from a single condensing point pattern image. Therefore, even if the specification of the lenslet array 2 is unknown, there is no hindrance to automatic processing and the convenience is improved.
Secondly, even if a condensing point is missing, there is no hindrance to automatic processing and convenience is improved.
Thirdly, since a processing table can be generated automatically and easily from a single condensing point pattern image, it is not necessary to generate a processing table by prior operation. Therefore, it is possible to realize a wavefront sensor that can speed up measurement and has a wide dynamic range.

  As described above, according to the wavefront sensor of the first embodiment, the lenslet array 2 that generates a number of condensing point patterns according to the wavefront shape of the incident light wave, and the number of images formed by the lenslet array 2 are imaged. A wavefront sensor comprising: a CCD 3 that picks up a light-condensing point pattern and converts it into an image signal; and a computing device 100 that computes and outputs a wavefront shape of a light wave from the image signal of the CCD 3 or a feature quantity corresponding to the wavefront shape; The arithmetic device 100 includes a two-dimensional coordinate group extraction unit 101 that calculates a two-dimensional coordinate group of each focal point in a two-axis orthogonal coordinate system defined on the image, and a first axis and a second axis of the orthogonal coordinate system. The coordinate values of the two-dimensional coordinate group on the axis are extracted and sorted according to the magnitude relationship, and the coordinate axis array generating unit 102 for generating the coordinate value array and the coordinate value array by the coordinate axis array generating unit 102 A difference value calculating means 103 for calculating a difference between two consecutive elements, and an array number detecting means 104 for detecting the total number of elements exceeding a threshold with respect to the difference between the two consecutive elements by the difference value calculating means 103; Based on the two-dimensional coordinate group extracted by the two-dimensional coordinate group extraction means 101 and the number of arrangements of the first axis and the second axis detected by the arrangement number detection means 104, the two-dimensional coordinate group and individual lenslets Since the correspondence means 105 for determining the correspondence relationship is provided, the correspondence processing between the coordinates of the focal point and each lenslet can be performed quickly and easily, and the cost of the wavefront sensor can be reduced. Can be achieved.

Embodiment 2. FIG.
In the first embodiment, the threshold value Th to be compared with DXi (DYi) in the calculation steps ST2c and ST3c can be defined as known information. It is desirable to detect more. Various methods based on some statistical value can be considered. For simplicity, it is also effective to set it to one half of the maximum value of DXi (DYi). Further, a known method using a statistical method such as a method of obtaining a standard deviation and multiplying by an appropriate coefficient α to obtain Th can be applied.

  Thus, since the wavefront sensor according to the second embodiment is configured as described above, the following effects can be obtained. That is, the threshold value Th can be determined by simple processing without using known information. Therefore, it is possible to realize a wavefront sensor that can perform high-speed measurement and is highly convenient.

Embodiment 3 FIG.
In the first embodiment, the method of generating the processing table for the association process while performing the association of the condensing point patterns (calculation step ST5) has been described, but it is naturally possible to perform only the association. is there. In addition, since the structure on the drawing of the wavefront sensor in Embodiment 3 is the same as that of FIG. 1 of Embodiment 1, it demonstrates using the structure of FIG.

  FIG. 7 is a flowchart showing signal processing contents of the wavefront sensor according to the third embodiment. In the flowchart of FIG. 7, the same steps as those in the flowchart of FIG. 4 are denoted by the same step numbers and description thereof is omitted. Calculation steps ST2d and ST3d are newly added to the calculation steps ST2 and ST3 in FIG. The calculation steps ST2d and ST3d and the calculation step ST7 described later are performed by the association means 105. Hereinafter, the processing content of the calculation step ST2d will be described first.

As already described, in the calculation step ST2c, the array size H is detected from DXi by the algorithm described in FIG. 5, but in the calculation step ST2d, an index 10h from DXi to Xi is added. As illustrated in FIG. 5, when the array DXi is referred to in the order of the index i, the index 10h is incremented each time an element DXi exceeding the threshold Th appears. Using this, it is possible to associate the index i of the array DXi with the index 10h. The index i of the array DXi has the relationship shown by the expression (1) with the index i of the array Xi, and the coordinate value Xi and the index 10h are associated by the above operation.
In the calculation step ST3d, the same processing as in the calculation step ST2d is performed on the arrays DYi and Yi, and the coordinate value Yi and the index 10v are associated.
In the calculation step ST7, the two-dimensional coordinate group (X, Y) is stored in the two-dimensional array with the indexes 10h and 10v based on the results of the calculation steps ST2d and ST3d.
Note that the threshold value Th may be defined as known information or may be determined using a statistical method as described in the second embodiment.

  As described above, in the wavefront sensor according to the third embodiment, it is possible to perform an automatic and simple process from a single condensing point pattern image and without generating a processing table. Therefore, a wavefront sensor having a high speed and a wide dynamic range can be realized.

Embodiment 4 FIG.
In each of the above-described embodiments, a high-order wavefront distortion is small as a precondition, and therefore a precondition that the condensing point pattern exists almost near the lattice point of a square lattice is necessary. On the other hand, in Embodiment 4, this restriction is relaxed.
FIG. 8 is a configuration diagram illustrating the wavefront sensor arithmetic device 100a according to the fourth embodiment.
The arithmetic device 100a according to the fourth embodiment includes a two-dimensional coordinate group extraction unit 101, a coordinate axis array generation unit 102, a difference value calculation unit 103, an array number detection unit 104, an association unit 105, and an out-of-region association unit 106. Yes. The basic configuration of the two-dimensional coordinate group extracting unit 101 to the associating unit 105 is the same as that of the two-dimensional coordinate group extracting unit 101 to the associating unit 105 shown in FIG. The difference is that it is a region. Further, the out-of-region association unit 106 is a unit that associates each lenslet 5 with a two-dimensional coordinate group belonging to the outside of the region of interest based on the processing result of the association unit 105.

The operation of the wavefront sensor according to the fourth embodiment will be described below.
FIG. 9 is an explanatory diagram illustrating an example of a condensing point pattern to be processed by the wavefront sensor arithmetic device 100a according to the fourth embodiment.
In FIG. 9, a two-dimensional coordinate group 50 is a coordinate group extracted from the condensing point pattern, and 51a and 51b indicate two-dimensional coordinates (X, Y). The example shown in FIG. 9 shows a case where a 9 × 9 condensing point pattern is detected without loss, and is greatly deviated from the square lattice arrangement due to higher-order wavefront distortion. Thereby, for example, although the two-dimensional coordinates 51a and 51b should be assigned different indexes 10h, the X coordinate is close to each other, so that an error cannot be detected by the algorithm shown in FIG. Embodiment 4 shows a method for avoiding such calculation errors.

FIG. 10 is an explanatory diagram of the association processing in the wavefront sensor arithmetic device 100a according to the fourth embodiment.
In the fourth embodiment, first, a region of interest is provided in a part of an image. FIG. 10A shows this, and the partial region 52 indicates this region of interest. In order to assign an index to the two-dimensional coordinate group in the partial region 52, first, the two-dimensional coordinate group in the partial region 52 of the two-dimensional coordinate group 50 is extracted as a processing target.

  Next, as shown in FIG. 10B, the calculation steps ST2 to ST6 described in the first embodiment are applied to the two-dimensional coordinate group in the partial region 52. The two-dimensional coordinates in the partial region 52 are in a range where the aberration is relatively small, and therefore the calculation steps ST2 to ST6 are completed without error.

  Next, the out-of-region association unit 106 calculates an approximate curve for the two-dimensional coordinate point group belonging to the same index 10h in FIG. For example, in FIG. 10C, an approximate curve 53 is an approximate curve of a two-dimensional coordinate point whose index 10h belongs to “A”. Next, in FIG. 10C, the vicinity is searched along the approximate curve 53 from the upper side (the side where the Y coordinate is small) to the lower side, and the index 10v is added one by one in the order found. At the same time, “A” is attached to the index 10h. The same operation is performed for other approximate curves. Thereby, it is possible to associate the two-dimensional coordinates outside the partial region 52 (two-dimensional coordinates with the index 10v of 1, 2, 8, 9 in FIG. 10C).

Next, in FIG. 10D, the out-of-region association means 106 calculates an approximate curve for the two-dimensional coordinate point group belonging to the same index 10v. For example, in FIG. 10D, the approximate curve 54 is an approximate curve of a two-dimensional coordinate point whose index 10v belongs to “1”. Next, in FIG. 10 (d), the vicinity is searched along the approximate curve 54 from the left side (side where the X coordinate is small) to the right side, and the index 10h is added one by one in the order found. At the same time, “1” is assigned to the index 10v. The same operation is performed for other approximate curves. Thereby, it is possible to associate the two-dimensional coordinates outside the partial region 52 (two-dimensional coordinates with the index 10h in FIG. 10D of A, B, H, and I).
With the above operation, the association process with the two-dimensional coordinate group 50 is completed.

  As described above, according to the wavefront sensor of the fourth embodiment, a region of interest is provided in a part of an image, a two-dimensional coordinate group extraction unit 101, a coordinate axis array generation unit 102, a difference value calculation unit 103, an array number detection unit. 104 and the association unit 105 perform processing on the region of interest and, based on the processing result of the association unit 105, associate the two-dimensional coordinate group belonging to outside the region of interest with each lenslet. Since the out-of-region associating means 106 is provided, the associating process can be performed even on a wavefront having a high order aberration. Therefore, a wavefront sensor with a wide dynamic range can be realized.

  1 aperture mask, 2 lenslet array, 3 CCD, 3a virtual frame, 4 partial light wave, 5 lenslet, 6 focused spot, 7 image, 8 focused spot pattern, 9 detection area, 10h, 10v index, 20 array, 21 threshold value, minimum value of 30x X coordinate, minimum value of 30y Y coordinate, maximum value of 31x X coordinate, maximum value of 31y Y coordinate, 32 detection area, 50 two-dimensional coordinate group, 51a, 51b two-dimensional coordinate, 52 partial area, 53, 54 approximation curve, 100, 100a arithmetic unit, 101 two-dimensional coordinate group extraction means, 102 coordinate axis array generation means, 103 difference value calculation means, 104 array number detection means, 105 association means, 106 out of area Association means.

Claims (3)

A lenslet array that generates a large number of condensing point patterns according to the wavefront shape of the incident light wave, and a two-dimensional detector that images a large number of condensing point patterns formed by the lenslet array and converts them into image signals And a wavefront sensor provided with an arithmetic device that calculates and outputs a feature quantity corresponding to the wavefront shape or wavefront shape of the light wave from the image signal of the two-dimensional detector,
The arithmetic unit is:
In a two-axis orthogonal coordinate system defined on the image, a two-dimensional coordinate group extraction means for calculating a two-dimensional coordinate group of each focal point;
A coordinate axis array generating means for extracting the coordinate values of the two-dimensional coordinate group in the first axis and the second axis of the orthogonal coordinate system and sorting the magnitude values, and generating a coordinate value array;
For the coordinate value array by the coordinate axis array generation means, difference value calculation means for calculating the difference between two consecutive elements;
With respect to the difference between two consecutive elements by the difference value calculation means, the array number detection means for detecting the total number of elements exceeding the threshold value;
Based on the two-dimensional coordinate group extracted by the two-dimensional coordinate group extraction means and the number of arrangements of the first axis and the second axis detected by the arrangement number detection means, the two-dimensional coordinate group and individual lenslets, A wavefront sensor provided with an association means for determining the correspondence relationship between   The wavefront sensor according to claim 1, wherein the threshold value is determined based on a statistic of a difference between two consecutive elements in the coordinate value array. A region of interest is provided in a part of the image, and a two-dimensional coordinate group extraction unit, a coordinate axis array generation unit, a difference value calculation unit, an array number detection unit, and an association unit perform processing on the region of interest,
2. An out-of-region association unit that associates a two-dimensional coordinate group belonging to the outside of the region of interest with each lenslet based on a processing result of the association unit. Alternatively, the wavefront sensor according to claim 2.

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