JP6786297B2 - Inspection equipment, inspection equipment control methods, and programs - Google Patents

Description

The present invention relates to an inspection device that scans light on a subject to obtain data on the subject, a control method for the inspection device, and a program.

Currently, as one of the inspection devices, a confocal laser scanning ophthalmoscope (SLO: Scanning Laser Opthermoscope) is applied in order to obtain data such as an image of the eye to be inspected. In an ophthalmologic imaging apparatus (one aspect of an inspection apparatus) represented by this SLO, an image is acquired by two-dimensionally scanning an illumination light on an eye to be inspected using a scanning optical system composed of two types of scanners. At this time, it is common to use a resonant scanner (resonant scanner) in the main scanning direction of the two-dimensional scanning and a galvano scanner in the sub scanning direction.

In recent years, in ophthalmologic imaging devices represented by such SLO devices, in order to make a good diagnosis of the eye to be inspected, it is required to increase the frame rate and refresh rate in the operation from data acquisition to image generation. There is. At the same time, it is also required to provide a high-resolution and low-distortion image to be used when actually inspecting the details of the fundus.

In the configuration disclosed in Patent Document 1, in the configuration of the resonant scanner and the galvano scanner, high resolution in image generation is achieved by reciprocating scanning of the resonant scanner. Further, regarding the deviation between the data acquisition position on the fundus and the corresponding pixel on the display screen, which will be described later, there is no corresponding data between the two data acquisition positions from the two data on the sub-scanning line. Pixel data is calculated. This eliminates the need to consider the deviation between the data acquisition position and the corresponding pixel, and provides a distortion-free image.

Here, the reciprocating scanning means that when scanning the illumination light in the main scanning direction, information is acquired in both the outward path and the return path during scanning. Further, increasing the frame rate means increasing the frame rate represented by the number of frames per unit time when one image displayed on the display screen is generated from data. Increasing the refresh rate means, for example, increasing the refresh rate, which is the replacement speed when replacing an image continuously displayed on the display screen as a moving image from the first image to the second image at the next timing. ..

Japanese Unexamined Patent Publication No. 2014-68703

The eye to be inspected repeats a movement called fixation tremor. Therefore, at the time of image acquisition, it is necessary to perform fundus tracking (fundus tracking) that detects the fixation tremor of the eye to be inspected and corrects the scanning position of the illumination light according to the fixation tremor. At that time, it is important to improve the responsiveness of fundus tracking by increasing the frame rate and the refresh rate in order to respond quickly to fixation tremor. Further, in actual inspection, it is required to provide a moving image with less flicker and good visibility. From this viewpoint as well, data acquisition for image generation and further increase in frame rate and increase in image generation are required. A refresh rate is desired.

Here, when trying to acquire data from a scanning system using a resonant scanner and a galvano scanner, it is necessary to achieve a high frame rate as well as a high resolution by simultaneously performing reciprocating scanning and interlaced scanning of the illumination light. Is also possible. The skip scanning is a scanning mode of illumination light in which a data acquisition range is divided into a plurality of rows, and for example, data acquisition from a field consisting of odd-numbered rows and data acquisition from a field consisting of even-numbered rows are alternately performed. Say.

The configuration disclosed in Patent Document 1 does not mention this jump scanning, and therefore does not suggest points to be noted when generating an image from the data obtained by the jump scanning. Further, in the case of the technique disclosed in Patent Document 1 as a countermeasure against the deviation between the above-mentioned data acquisition position and the corresponding pixel, two data acquisitions equidistant in the sub-scanning direction centering on the arrangement of the pixels for calculating the data. Position data is used. Therefore, if the distance between these two data becomes large at that time, it is possible that the obtained pixel data cannot reflect the actual data and a so-called blurred image may be generated.

In view of the above circumstances, the present invention provides an inspection device in which the frame rate has been increased when an image of a subject with reduced image distortion is generated by scanning the illumination light.

In order to solve the above problems, the inspection apparatus according to the embodiment of the present invention includes a first scanning member that reciprocally scans the illumination light in the main scanning direction of the subject.
A second scanning member that scans the illumination light at a constant velocity in a sub-scanning direction that intersects the main scanning direction in the subject.
The first scanning member and the second scanning member cause the illumination light to be two-dimensionally scanned in the first field in the data acquisition range of the subject, and the data acquisition range is different from that of the first field. A scanning control means for two-dimensionally scanning the illumination light in two fields,
In each of the first field and the second field, an acquisition position setting means for setting a data acquisition position for acquiring data from the return light of the illumination light from the subject, and
In order to generate data at new positions arranged at equal intervals in the sub-scanning direction, at least two of the data acquisition positions in the first field and the second field in the order closer to the new position. A selection means for selecting the data acquired at the data acquisition position, and
Have a, and an image generating means for generating an image of the object using the data of the new position of the generated from the selected data,
The first scanning member includes a mirror that reflects the illumination light, and the mirror so as to cause acceleration / deceleration in the scanning speed when the mirror reflects the illumination light and scans in the data acquisition range. characterized Rukoto such from the member to be driven.

According to the present invention, it is possible to provide an inspection apparatus having an advanced frame rate when generating an image of a subject with reduced image distortion by scanning illumination light.

It is the schematic which shows the structure of the SLO apparatus which concerns on Example 1 of this invention. It is a flowchart which showed the flow of image acquisition which concerns on Example 1 of this invention. It is a figure explaining the scanning of the illumination light on the correction photodiode in the configuration shown in FIG. It is a figure which shows the relationship between the scanning position and time in the main scanning direction of the resonant scanner in the configuration shown in FIG. 1, and is the figure which shows the signal which a correction photodiode outputs. It is a figure which illustrates the scanning locus and a sampling point of an odd field. It is a figure which shows the positional relationship between each scanning locus and a sampling point of an odd-numbered field and an even-numbered field, and a desired sampling point for correction of image distortion in a sub-scanning direction. It is a flowchart which showed the flow of image acquisition of the moving image which concerns on Example 2 of this invention.

As described above, in the scanning optical system using the resonant scanner, the resolution can be increased by acquiring information by reciprocating scanning. On the other hand, the high frame rate can be achieved by performing interlaced scanning of the illumination light and acquiring images in each of the odd-numbered fields and the even-numbered fields. In the embodiment described below, by performing the jump scanning and the reciprocating scanning together, a high resolution is achieved in addition to a high frame rate, and a high-definition image with less distortion is provided.

Here, for example, in the case of jump scanning of illumination light in the fundus, when the scanning area is defined in a grid pattern in the main scanning direction (horizontal direction) and the sub-scanning direction (vertical direction), the first line, the third line, and the like. The fifth line ... means scanning the illumination light every other line in the main scanning direction. The odd field refers to the field that scans the 1, 3, 5 ... Rows, and the even field refers to the field that scans the 2, 4, 6 ... rows. By combining the data obtained from both fields, all the data in the scanning area can be obtained. In the case of reciprocating scanning in an odd-numbered field, the 1, 5, 9 ... Lines correspond to the outward scanning by the illumination light, and the 3, 7, 11 ... Lines correspond to the return scanning by the illumination light. Here, for convenience of explanation, each row in the odd-numbered field and each row in the even-numbered field have the same width in the sub-scanning direction. However, the even-numbered fields may be set with an arbitrary distance shifted in the sub-scanning direction with respect to the odd-numbered fields. In other words, the odd field may be the first field, the even field may be the second field, and further fields may be set, for example, a third field may be set. That is, after the scanning of the illumination light in the odd field is completed, the irradiation position (scanning start position) of the illumination light is shifted in the sub-scanning direction in order to scan the illumination light in the next field, but the shift amount is odd. It does not have to be the amount of shift for one line in the field.

The one-frame image is generated from the obtained data by synthesizing the data obtained from each of these odd-numbered fields and even-numbered fields. As described above, in the following embodiment, data is obtained from two different fields on the fundus by jump scanning of the illumination light, and an image is generated and updated. In addition, a high frame rate is achieved by obtaining data from both the outward path and the return path in scanning the illumination light. More specifically, in Patent Document 1, data of all rows in the data acquisition range was obtained by reciprocating scanning, but in this embodiment, all rows are obtained by performing reciprocating scanning of odd-numbered frames and reciprocating scanning of even-numbered frames. I am going to get the data of.

Hereinafter, exemplary examples for carrying out the present invention will be described in detail with reference to the drawings. However, the shape described in the following examples, the relative positions of the components, and the like are arbitrary and can be changed according to the configuration of the device to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are the same or functionally similar.

(Example 1)
FIG. 1 is a schematic diagram of the configuration of the SLO apparatus according to the first embodiment of the present invention. The application target of the present invention is not limited to the SLO apparatus. For example, it can be applied to an inspection device such as an OCT device or an AO-SLO device that scans illumination light (measurement light) with an eye to be inspected, particularly an ophthalmologic imaging device that scans with a resonant scanner.

The SLO device shown in FIG. 1 has a data acquisition unit 100, a system unit 101, and a display unit 102. The data acquisition unit 100 acquires data related to the fundus Er such as luminance information by scanning the illumination light on the eye to be inspected (fundus Er in this embodiment). The system unit 101 controls the data acquisition unit 100 and generates an SLO image based on the data acquired from the data acquisition unit 100. The display unit 102 displays the SLO image generated by the system unit 101. In this embodiment, the configuration in which each unit is arranged independently is illustrated, but each unit may be appropriately integrated according to the arrangement conditions such as integrating the system unit 101 and the display unit 102. .. In addition, it may be combined with other devices such as an OCT device in whole or in part.

First, the configuration of the data acquisition unit 100 will be described. An objective lens 1, a galvano scanner 2, a resonant scanner 3, lenses 4 and 5, a mirror 6, and an SLO light source 8 are sequentially arranged on the optical path L1 facing the eye to be inspected. A photodiode 7 is arranged on the reflected optical axis of the mirror 6. These optical elements constitute an SLO optical system for fundus Er.

The lens 4 is driven by a motor (not shown) in the direction of the optical axis indicated by the arrow in the figure for focusing of the SLO optical system. The SLO light source 8 emits light having a wavelength near 780 nm as illumination light. The photodiode 7 detects the return light from the fundus Er illuminated by the illumination light. The mirror 6 is composed of a perforated mirror or a prism in which a metal or the like is deposited on a hollow mirror, and separates the illumination light emitted from the SLO light source 8 and the return light from the fundus Er.

The illumination light emitted from the SLO light source 8 passes through the mirror 6, passes through the lenses 5 and 4, and is scanned by the resonant scanner 3 and the galvano scanner 2 on the fundus Er. The return light from the fundus Er is reflected by the mirror 6 after returning in the same path as the illumination light, and is guided to the photodiode 7.

The galvano scanner 2 and the resonant scanner 3 constitute a scanning optical system that scans the illumination light emitted from the SLO light source 8 on the fundus Er. The resonant scanner 3 scans the illumination light on the fundus Er in the main scanning direction (X direction), and the galvano scanner 2 scans the illumination light on the fundus Er in the sub-scanning direction (Y direction). The resonant scanner 3 can scan the illumination light in a line in the main scanning direction on the fundus Er by deflecting the illumination light by a mirror that vibrates at high speed at the resonance frequency. The galvano scanner 2 operates in a constant velocity linear motion to further deflect the light deflected in the main scanning direction by the resonant scanner 3 in the sub-scanning direction. With such a resonant scanner 3 and a galvano scanner 2, the illumination light can be scanned two-dimensionally on the fundus Er.

The resonant scanner 3 is generally composed of a mirror that reflects illumination light and a member that vibrates the mirror about an axis. When the member reflects the illumination light by the mirror and scans on the fundus Er, the mirror is driven by causing acceleration / deceleration in the scanning speed. It is known that the resonant scanner 3 changes its scanning state such as its resonance frequency (period of vibration) and amplitude due to the influence of environmental changes and the like. In this embodiment, the correction photodiode 9 is arranged to detect the scanning state of the resonant scanner 3. The correction photodiode 9 is arranged at a position that does not overlap with the scanning range defined by the XY coordinate plane when the illumination light is two-dimensionally scanned on the fundus Er by the resonant scanner 3 and the galvano scanner 2. .. The details of detecting the scanning state of the resonant scanner 3 using the correction photodiode 9 will be described later when the flow of image acquisition is described.

The system unit 101 is composed of a control unit 10 that controls the data acquisition unit 100 and an image generation unit 11 that generates an SLO image. The control unit 10 controls the galvano scanner 2, the resonant scanner 3, the lens 4, the photodiode 7, the SLO light source 8, and the correction photodiode 9. The image generation unit 11 generates an SLO image based on the data acquired from the photodiode 7. The display unit 102 displays the SLO image generated by the image generation unit 11.

Next, the flow of the process executed at the time of image acquisition in the SLO apparatus including the data acquisition unit 100, the system unit 101, and the display unit 102 described above will be described with reference to the flowchart of FIG. Further, details of each step will be described as appropriate with reference to FIGS. 3 to 6. The flowchart constitutes one aspect of the control method of the inspection device according to the first embodiment, and each step of the flowchart constitutes each step of the control method.

In step S201, the resonant scanner 3 scans the illumination light on the correction photodiode 9. Specifically, the control unit 10 starts driving the resonant scanner 3 and positions the galvano scanner 2 at a predetermined angle in the sub-scanning direction corresponding to the correction photodiode 9. After that, the control unit 10 turns on the SLO light source 8. By the above operation, the illumination light from the SLO light source 8 is reciprocally scanned a plurality of times in the main scanning direction on the correction photodiode 9 with the scanning locus 13 as shown in FIG.

Note that FIG. 3 is a diagram for explaining the scanning of the illumination light on the correction photodiode 9, together with the correction photodiode 9 and the correction photodiode 9 in the data acquisition range in the fundus Er. The relationship with the corresponding surface on the surface perpendicular to the optical axis is shown. That is, the acquisition range 12 shown in the figure corresponds to the acquisition range of data on the XY surface when the fundus Er is two-dimensionally scanned by the illumination light. The correction photodiode 9 is arranged at a position where the scanning locus 13 during the one-dimensional scanning executed in step S201 and the acquisition range 12 which is the data acquisition range during the two-dimensional scanning of the fundus Er are not overlapped.

When scanning the illumination light on the scanning locus 13, the relationship between the scanning position and the time in the main scanning direction of the illumination light by the resonant scanner 3 is a sinusoidal operation as shown in FIG. 4A. In step S201, the illumination light is reciprocally scanned a plurality of times on the correction photodiode 9, and FIG. 4A shows a part of the reciprocating scans a plurality of times. The point p on the vertical axis in FIG. 4A indicates the position of the correction photodiode 9 in the main scanning direction. According to the figure, the correction photodiode 9 receives the illumination light from the SLO light source 8 at the timings t1, t2, and t1'. FIG. 4B shows a signal output when the correction photodiode 9 receives the illumination light.

ここでＰｘはレゾナントスキャナ３の主走査方向の走査位置、Ａはレゾナントスキャナ３の振幅、ｔは時間を示す。更に、Ｔはレゾナントスキャナ３の振動周期を示し、Ｔ＝ｔ１‘−t１で表わされる。また、Ｂは、レゾナントスキャナ３が１周期毎に出力する同期信号のタイミングｔ０とレゾナントスキャナ３の往路と復路の切り替わりのタイミングとの差分を示す。正弦波動作の山と谷とにおいて、レゾナントスキャナ３の往路と復路とが切り替わっている。 Next, in step S202, the control unit 10 estimates the operation of the resonant scanner 3 using the timings t1, t2, and t1'of the signals output by the correction photodiode 9 in step S201. The following equation (1) is used in the estimation.

Here, Px indicates the scanning position in the main scanning direction of the resonant scanner 3, A indicates the amplitude of the resonant scanner 3, and t indicates the time. Further, T indicates the vibration period of the resonant scanner 3 and is represented by T = t1'−t1. Further, B indicates the difference between the timing t0 of the synchronization signal output by the resonant scanner 3 for each cycle and the timing of switching between the outward path and the returning path of the resonant scanner 3. At the peaks and valleys of the sine wave operation, the outward path and the return path of the resonant scanner 3 are switched.

The above-mentioned constants A and B can be obtained by solving the two equations in which (t1, p) and (t2, p) are substituted for (t, Px) in the above equation (1). Therefore, the operation of the resonant scanner 3 can be estimated by the equation (1). The module corresponding to the correction photodiode 9 and the control unit 10 that detects the vibration cycle of the resonant scanner 3 based on the output from the correction photodiode 9 described above is the cycle in the present embodiment. Configure the detection means. Similarly, these configurations constitute the amplitude detecting means in the present embodiment when detecting the amplitude of the vibration of the resonant scanner 3.

Next, in step S203, the control unit 10 determines the sampling timing of the data in the odd-numbered field and the even-numbered field to be executed in the subsequent steps S204 and 205. At that time, the estimation result of the operation of the resonant scanner 3 obtained in step S202 described above is used. For example, the sampling timing when acquiring the SLO image (data) at the point of the main scanning direction px1 (not shown) can be obtained by substituting Px = px1 into the equation (1) and solving for t. By performing the above calculation for all the positions where data is to be acquired in the main scanning direction in the SLO image of one frame, it is possible to obtain the sampling timing for all the data acquisition. In this embodiment, the sampling timing (data acquisition timing) is determined so that the data acquisition positions in the odd-numbered field and the even-numbered field are aligned on a straight line in the sub-scanning direction. Further, as the data acquisition position on the fundus, the intersection position shown in FIG. 6 to be described later is obtained based on the estimated operation of the resonant scanner 3.

Next, in step S204, the control unit 10 scans the fundus Er in an odd-numbered field in the jump scan. As described above, in steps S201 to S203, the galvano scanner 2 was positioned at a predetermined angle in the sub-scanning direction corresponding to the correction photodiode 9. In step S204, the galvano scanner 2 is moved linearly at a constant velocity in the sub-scanning direction, so that the resonant scanner 3 and the galvano scanner 2 perform two-dimensional scanning of the illumination light.

FIG. 5 illustrates a scanning locus and a sampling point thereof in scanning the illumination light in an odd-numbered field, which is performed in step S204. In the figure, the scanning locus is drawn by a solid line, and the sampling point is indicated by a black circle. In the figure, from the left of the sampling point O11 to the right of O17, the scanning locus indicated by the arrow pointing to the right is shown. Further, from the right of the sampling point O37 to the left of O31, the scanning locus indicated by the arrow pointing to the left is shown. Looking at the direction of the arrow in the figure, it can be seen that the outward path and the return path of the resonant scanner 3 are switched between the right end and the left end of the scanning locus. The points indicated by black circles in the figure indicate sampling points of odd-numbered fields in the data acquisition region in the fundus Er. In the figure, as described above, data is acquired from both the outward path and the return path of the resonant scanner 3 so that black circles exist on both the outward path and the return path in the reciprocating scan. The alternate long and short dash line M1 in the figure indicates the center of the illumination light by the resonant scanner 3 in the main scanning direction in the main scanning direction.

The sampling points of all the acquired odd-numbered fields are sampled at equal intervals in the main scanning direction. This is because the sampling timing is calculated so that a desired sampling point can be obtained in step S203, and sampling is performed based on the calculation. However, the intervals of sampling points in the sub-scanning direction are not evenly spaced. This is due to the fact that the operation of the resonant scanner 3 changes in a sinusoidal shape shown in FIG. 4 with time.

In the following step S205, the control unit 10 scans the even-numbered fields in the jump scan with respect to the fundus Er. At this time, the control unit 10 shifts the scanning position of the even-numbered field by a predetermined amount in the sub-scanning direction with respect to the odd-numbered field so that the scanning positions of the odd-numbered field and the even-numbered field do not overlap. The predetermined amount in this embodiment corresponds to the spacing of the pixel rows in the sub-scanning direction in the image displayed on the display unit 102, and is an odd-numbered field and an even-numbered field alternately arranged on the sub-scanning line in the center of the main scanning range. Approximately equal to the sampling point interval.

FIG. 6 shows the scan loci and sampling points of the odd and even fields scanned in steps S204 and S205. The scanning locus of the odd-numbered field is shown by a solid line on FIG. 6, and shows the scanning locus of the illumination light performed in step S204. On the other hand, the scanning locus of the even-numbered field is shown by a broken line, and shows the scanning locus of the illumination light performed in step S205. The sampling points in each of the odd and even fields are indicated by black and white circles, respectively. Specifically, in the figure, black circles P11, P12, P13, P33, P32, P31, P51, P52, ... Indicates sampling points of odd-numbered fields. Further, white circles P21, P22, P23, P43, P42, P41, ... Indicates sampling points of even-numbered fields.

Focusing on the sampling points on the alternate long and short dash line M1 located at the center of the main scanning direction shown in FIG. 6, the intervals in the sub-scanning direction between the sampling points of the odd-numbered fields and the sampling points of the even-numbered fields are evenly spaced. It has become. Specifically, the intervals between the sampling points of the black circle P11, the white circle P21, the black circle 31, the white circle P41, and the black circle P51 are all the same distance. By setting the predetermined amount of offset in this way to an appropriate value, it is possible to make the sampling points on the fundus and the pixels in the display screen corresponding to the sampling points correspond to each other without deviation. As a result, it is possible to prevent the image from being distorted in the sub-scanning direction at the center of the main scanning direction.

However, focusing on the alternate long and short dash lines M2 and M3 away from the center in the main scanning direction, it can be seen that the sampling points in the sub-scanning direction are not evenly spaced. Specifically, the intervals between the sampling points of the black circle P12, the white circle P22, the black circle P32, the white circle P42, and the black circle P52 are not equal intervals, but differ depending on the sampling points. The fact that the sampling points are not evenly spaced in the sub-scan direction means that the SLO image is distorted in the sub-scan direction. Further, according to the figure, it is assumed that the sampling interval in the sub-scanning direction deviates from the equal interval as the distance from the center in the main scanning direction increases, and the image distortion in the sub-scanning direction also increases. Here, if the intervals are not equal, it means that there are a plurality of types of intervals between sampling points (3 in this embodiment), and if the intervals are not equal, the difference between the plurality of types of intervals becomes larger. It means to go.

In step S206, the image generation unit 11 corrects the distortion in the sub-scanning direction generated in steps S204 and S205 described above to generate an image of one frame. In this embodiment, as described above, the distortion in the sub-scanning direction does not occur on the alternate long and short dash line M1, but occurs on the alternate long and short dash lines M2 and M3. Therefore, the correction of the distortion in the sub-scanning direction performed in this step S206 is executed for the data sampled on the alternate long and short dash lines M2 and M3. The sampled data is used to generate an SLO image as a pixel value such as a brightness value in the corresponding pixel. Also in the correction, the data is obtained as a pixel value. Therefore, in the following description, the corrected data will be described as a pixel value.

Here, as described above, with respect to each sampling point on the alternate long and short dash line M1, data can be obtained correspondingly without being displaced from the pixels of the display screen. FIG. 6 also shows the positions where the dotted line passing through each sampling point on the alternate long and short dash line M1 and orthogonal to the alternate long and short dash line M1 intersects with the alternate long and short dash lines M2 and M3. With respect to these intersection positions, there are pixels that correspond to each other on the display screen. Therefore, the distortion correction of the sub-scanning method is performed by estimating the pixel values at these intersecting positions arranged at equal intervals in the sub-scanning direction from the actually acquired sampling point data. In this embodiment, in the case of the alternate long and short dash line M2, from the sampling point data of the black circle P12, the white circle P22, the black circle P32, the white circle P42, and the black circle P52 actually acquired, the intersection positions P12', P22', P32', and P42 Estimate each pixel value at'and P52'. It is preferable that these intersection positions are preset by the image generation unit 11 as new positions for generating data for correcting image distortion.

この式（２）に実際に取得されたサンプリングデータの中から、交差位置Ｐ２２’に対して近い側から順に２点のサンプリングポイントのデータを選択し代入する。なお、この時、これら２点のサンプリングポイントを、時系列において連続してデータ取得が行われた奇数フィールドおよび偶数フィールドより、フィールドを問わずに選ぶ。 Hereinafter, a case where the pixel value of the intersection position P22'on the alternate long and short dash line M2 is estimated will be specifically described as an example. Pixel value estimation is performed using the linear equation shown in equation (2). In the formula (2), Py indicates the coordinate position of the sampling point in the sub-scanning direction (coordinate position on the alternate long and short dash line M2), E indicates the pixel value in Py, and C and D indicate the coefficient.

From the sampling data actually acquired in this equation (2), the data of two sampling points are selected and substituted in order from the side closest to the intersection position P22'. At this time, these two sampling points are selected regardless of the field from the odd-numbered field and the even-numbered field in which data is continuously acquired in the time series.

Estimating Pixel Values or Data Distances between the intersections shown by the white triangles in FIG. 6 and each of all the preset sampling points on the same sub-scanning line shown by the black and white circles in FIG. However, it is required. Further, the data of the sampling point having the shortest distance and the sampling point having the next shortest distance by comparing these plurality of distances is selected as the data to be used for the distortion correction. In the embodiment described here, the data of two sampling points are used from the side with the shortest distance, but three or more data may be used. However, depending on the value of the offset amount, it is possible that the second or third data is too far away from the intersection position to be used for distortion correction. In this case, a distance threshold value may be provided to select data at sampling points at a distance within the threshold value from the intersection position where the pixel value or data is estimated.

As described above, if both of the two sampling points are in the odd field, both of them may be selected from the odd field. If these two sampling points are in both the odd-numbered field and the even-numbered field, they can be selected from both fields. Normally, data correction in jump scanning is performed for each field, and data candidates used for correction are selected from within that field. On the other hand, in this embodiment, all of the data obtained in each of the plurality of consecutive (two in this embodiment) fields set to generate one image in time series , It is decided to be a data candidate used for pixel value estimation.

Specifically, when the intersection position P22'is taken as an example, the sampling points of two points from the side close to the intersection position P22'are black circles P12 and white circles P22. Therefore, the coordinate positions and pixel values of the black circles P12 and the white circles P22 in the sub-scanning direction are set to (Py12, E12) and (Py22, E22), respectively, and substituted into (Py, E) of the equation (2). From the two equations obtained, the constants C and D can be obtained. The coordinate position of the sampling point actually acquired here is calculated by the control unit 10. The control unit 10 calculates the coordinate position based on the relationship between the operation of the resonant scanner 3 estimated in step S202, the sampling timing obtained in step S203, and the speed of the galvano scanner 2.

Next, using the obtained constants C and D, substituting the coordinate position Py22'in the sub-scanning direction of the intersection position P22', which is the desired sampling point, into Py of the equation (2), the pixel value E22 of the desired sampling point is substituted. 'Can be estimated. As described above, since the data of the sampling point closest to the desired sampling point can be selected regardless of both fields, the accuracy of estimating the pixel value in the display screen described above can be improved.

On the other hand, as described above, the general correction of image distortion in the sub-scanning direction is performed for each field. Therefore, in order to obtain the corrected data, it is necessary to select two points closest to the position where the data is generated in the field from the sampling points constituting the field. Therefore, there may be a case where a distant point must be selected as compared with the case of the present embodiment described above. For example, when estimating the pixel value of the intersection position P22'in the odd field shown in FIG. 6, data of two sampling points in the odd field of the black circle P12 and the black circle P32 are selected. As a result, the accuracy of estimating the pixel value becomes low, which causes distortion and blurring of the image.

In the above-mentioned example, a combination of black circles P12 and white circles P22, which are sampling points, was selected. However, even when the combination of the white circle P22 and the black circle P32, which are sampling points, is selected, the sum of the distances from the intersection position P22'to these two points is the sum of the distances in the case of the combination of the black circle P12 and the white circle P22. Is equal to or close to. Alternatively, the distance from the intersection position P22'to the black circle P12 and the distance to the black circle P32 are equal to or close to each other. Therefore, even when these sampling points are selected, it is possible to obtain the effect that the pixel value can be estimated equally well.

The method of estimating the pixel value of the intersection position P22'described above is also applied to all of the other desired intersection positions, and the pixel value at each intersection position is estimated. For example, the pixel value at the intersection position P23'is estimated using the data of the black circles P13 and the black circles P33, which are sampling points. The pixel value of the intersection position P32'is estimated using the data of the black circles P32 and the white circles P42 or the data of the white circles P22 and the black circles P32 which are sampling points. That is, pixel values at all the intersection positions in the image of one frame are generated from both the odd field and the even field. In this embodiment, it is not necessary to estimate the pixel value at the intersection position on the alternate long and short dash line M1, but the same processing may be required on the alternate long and short dash line M1 depending on the offset amount when generating the even-numbered field. Become.

Next, in step S207, the control unit 10 displays the image generated from the pixel values estimated in step S206 on the display unit 102. In this embodiment, replacing the frame generated from the sampling points of the odd-numbered field and the even-numbered field with the frame consisting of the intersection positions and setting the pixel value of the intersection position to the estimated pixel value is referred to as distortion correction. .. In this embodiment, as a result of correction of distortion in the sub-scanning direction of the SLO image by the image generation unit 11 in step S206, distortion of the image of one frame is generated using all the data of both the odd-numbered field and the even-numbered field. It will be corrected. Therefore, the image generated in step S207 and displayed on the display unit 102 is not in units of one field but in units of one frame.

As described above, in the present embodiment, a scanning optical system including a resonant scanner 3 and a galvano scanner 2 is used, and data is obtained from two fields by reciprocating scanning and jump scanning of illumination light to obtain distortion in the sub-scanning direction. Not producing an image. Specifically, the data of sampling points at a plurality of positions on the side close to the desired sampling point (referred to as the intersection position in this embodiment) from which the pixel value should be obtained is used regardless of the odd field and the even field. The pixel value of the desired sampling point is estimated. By generating an image using the estimated pixel values, it is possible to provide a one-frame image in which distortion in the sub-scanning direction is corrected with high accuracy.

For example, Patent Document 1 aims to deal with distortion in the sub-scanning direction of an image caused by reciprocating scanning of illumination light using a resonant scanner. However, in the disclosed configuration, distortion is corrected every time one frame is obtained when the illumination light is reciprocally scanned and sequentially scanned. Therefore, if the method disclosed in this embodiment, which performs reciprocating scanning and jump scanning, is applied, the distortion correction process is executed for each field. As described above, in the method disclosed in Patent Document 1, the pixel value of the desired sampling point is estimated using the data of the sampling points equidistant from the desired sampling position in the sub-scanning direction. In addition, a distortion-corrected image is obtained from a field composed of estimated pixel values. Therefore, the case where the sampling point of the data to be used is far from the desired sampling point is also included. In this case, the image after distortion correction is blurred in the sub-scanning direction. Here, for example, after performing this processing in each of the odd-numbered fields and the even-numbered fields, consider a case where a new one-frame image is generated from these fields as in this embodiment. In this case, since the blurred portions are overlapped with each other, the blur becomes even larger. As described above, such image blurring can be avoided by appropriately selecting the data of the odd-numbered field and the even-numbered field, obtaining the pixel value, and generating an image of one frame from both fields.

In the above-described first embodiment, when estimating the pixel value, a linear equation is used as shown in the equation (2), but an N-order equation such as a cubic equation or a quintic equation may also be used. Good. At that time, for the desired sampling points arranged at equal intervals in the sub-scanning direction, the same effect can be obtained by selecting N + 1 sampling points in the order of proximity to the desired sampling points regardless of the odd-numbered field or the even-numbered field. Obtainable.

Further, in this embodiment, after the data is acquired from the odd-numbered fields, the data is acquired from the even-numbered fields, and the distortion-corrected image is generated using the data of these two fields. However, the order of data acquisition is not limited to this, and may be replaced. That is, the same effect can be obtained by generating a one-frame image using the data of different fields acquired continuously in time series. Further, in this embodiment, the even-numbered fields are generated by offsetting the odd-numbered fields to the lower side of the paper on FIG. However, the same effect can be obtained by generating an even field by offsetting it on the upper side of the paper. Further, the number of fields is not limited to two defined by odd and even numbers, and may have additional fields. From the above, the odd field corresponds to the first field and the even field corresponds to the second field different from the first field in this embodiment.

(Example 2)
In the first embodiment described above, a case of generating a still image of one frame is described. On the other hand, the second embodiment described below is intended for the case of generating a moving image. The configuration of the SLO apparatus according to the second embodiment is the same as the configuration of the first embodiment shown in FIG. Therefore, the second embodiment described below will be described with reference to FIG. 7, which is a flowchart showing a processing flow different from that of the first embodiment. Further, in the flowchart in FIG. 7, the same number is assigned to the step of performing the same process as the process executed in the first embodiment.

In the first embodiment, an odd-numbered field and an even-numbered field are used to generate a one-frame image in which distortion in the sub-scanning direction is corrected. In the second embodiment, it is intended to continuously generate and display it as a moving image. Specifically, in the flowchart shown in FIG. 7, first, the control unit 10 goes through the operations from step S201 to step S212. After that, data acquisition from odd-numbered fields, data acquisition from even-numbered fields, and operations by the image generation control unit 10 and the like are repeated from step S208 to step S212. In the flowchart of FIG. 7, N indicates the number of repetitions. The moving image described in the second embodiment is mainly used in the ophthalmologic imaging apparatus when aligning the eye to be inspected with the apparatus.

The details of the operation performed in each step will be described below. First, when the control unit 10 starts the process of generating the SLO moving image, the flow proceeds to step S201. Similar to the first embodiment, in steps S201 and S202, the control unit 10 estimates the operation of the resonant scanner 3 using the data obtained by scanning the illumination light on the correction photodiode 9.

In the following step S203, the control unit 10 determines the sampling timing in the odd-numbered field and the even-numbered field performed in the steps S204 and S205. When the sampling timing is determined, the control unit 10 advances the flow to the operation after step S208, which is a process for actually displaying the SLO moving image. In step S204, the control unit 10 scans the N-th illumination light in the odd-numbered field and acquires data from the odd-numbered field in order to display the moving image of the SLO. In the following step S209, the control unit 10 determines whether or not the scanning of the illumination light in the odd-numbered field and the data acquisition performed in step S204 are performed for the second time or more.

When the control unit 10 determines that N is 1 in step S209 and the first data acquisition has been performed, the flow proceeds sequentially to step S205, step S206, and step S207. As a result, using the data obtained from the first odd-numbered field and the data obtained from the first even-numbered field, the image generation unit 11 generates a one-frame image in which distortion in the sub-scanning direction is corrected, and The display is performed by the display unit 102. The operation executed in each of these steps is the same as the content shown in the first embodiment.

On the other hand, when N is 2 or more in step S209 and it is determined that the scanning of the illumination light in the odd field and the data acquisition are the second and subsequent times, the control unit 10 advances the flow to step S210. In step S210, the image generation unit 11 generates an image corrected for distortion in the sub-scanning direction based on the data obtained from the Nth odd-numbered field and the data obtained from the N-1th even-numbered field. In this embodiment, if the data of the odd-numbered field and the even-numbered field are acquired respectively, the distortion in the sub-scanning direction can be corrected. Therefore, the most recently acquired data of the Nth odd-numbered field and the data of the N-1th even-numbered field acquired immediately before the data are used to generate an image in which the distortion in the sub-scanning direction is corrected. I do. Since the details of the distortion-corrected image generation are the same as those in the first embodiment, the description thereof will be omitted here.

Next, in step S211 the one-frame image in which the distortion in the sub-scanning direction is corrected in step S210 is displayed by the display unit 102 by the control unit 10. Further, in the next step S205, the Nth scanning of the illumination light in the even-numbered field and data acquisition are performed. As a result, in the following step S206, the data of the Nth odd-numbered field and the Nth even-numbered field acquired most recently are aligned, and the image generation unit 11 performs distortion correction using these data. .. In the following step S207, the one-frame image in which the distortion in the sub-scanning direction is corrected in step S206 is displayed on the display unit 102.

After that, the processes from step S208 to step S212 are repeated by the control unit 10 and the like until the SLO moving image generation is completed in step S212. As a result, the moving image corrected for the distortion in the sub-scanning direction can be displayed on the display unit 102. By continuously displaying the images obtained according to the above-described operation, it is possible to provide a moving image in which distortion is suppressed in the sub-scanning direction at a high frame rate.

In the above-described embodiment, an SLO apparatus using the resonant scanner 3 and the galvano scanner 2 for illumination light scanning is described as an example. In this example, the resonant scanner 3 constitutes a first scanning member that reciprocally scans the illumination light in the main scanning direction in the eye to be inspected. Further, the galvano scanner 2 constitutes a second scanning member that scans the illumination light at a constant velocity in the sub-scanning direction that intersects the main scanning direction in the eye to be inspected. The main scanning direction and the sub-scanning direction are preferably orthogonal to each other as in the embodiment, but may be used as long as they are set to intersect at a certain angle. The control unit 10 causes the illumination light to be two-dimensionally scanned in an odd-numbered field in the data acquisition range in the eye to be inspected by both scanners described above as scanning control means, and two-dimensionally scans in an even-numbered field different from the odd-numbered field in the data acquisition range. Let me. The photodiode 7 and the module of the control unit 10 that causes the photodiode to acquire data such as brightness at the timing described above constitute a data acquisition means. Further, the control unit 10 further constitutes an acquisition position setting means for determining a data acquisition position for acquiring data from the return light of the illumination light from the eye to be inspected in each of the odd-numbered field and the even-numbered field.

In addition, the image generation unit 11 constitutes a generation position setting means for setting a data generation position to be a desired sampling point in advance. More specifically, the image generation unit 11 sets a plurality of data generation positions for image generation, which are arranged at the first interval in the main scanning direction and at the second interval in the sub-scanning direction. .. In the above-described embodiment, the first predetermined interval coincides with the interval of the sampling points determined in step S203, but the interval is not limited to this as long as it is set to an equal interval. Further, the second interval at the data generation position is set so as to be evenly spaced in the sub-scanning direction. The image generation unit 11 further constitutes a selection means for selecting data acquired at at least two positions of the data acquisition positions set in the odd-numbered field and the even-numbered field that are continuous in time series in the order closer to the data generation position. To do. The image generation unit 11 generates data of the data generation position from the selected data, and generates an image of the subject based on the generated data as an image generation means.

As described above, the control unit 10 obtains a predetermined amount as an offset amount based on the scanning speed at the time of constant velocity linear scanning of the illumination light by the galvano scanner 2 and the output of the period detecting means. Further, the control unit 10 determines the timing of acquiring the data so that the data acquired from the odd-numbered field and the even-numbered field are arranged in a straight line in the sub-scanning direction based on the output of the periodic detection means and the output of the amplitude detection means. ..

In the above-described embodiment, an example in which a resonant scanner is used in the main scanning direction is shown, but a galvano scanner in which acceleration / deceleration occurs during illumination light scanning, an acoustic optical element (Acousto-Optic Defector), or a MEMS (Micro Electro Mechanical System) scanner The present invention can be applied even when the above is used in the main scanning direction.

Further, in the above-described embodiment, the illumination light is scanned by the scanning means in which acceleration / deceleration occurs in the main scanning direction, and the illumination light is scanned by the scanning means in which the sub-scanning direction performs a constant velocity linear motion. However, the same effect can be obtained even in a configuration in which these scanning means are replaced so that the main scanning direction is scanning in a constant velocity linear motion and the sub scanning direction is scanning in which acceleration / deceleration occurs. In this case, referring to the flowchart shown in FIG. 2, data will be acquired at equal intervals in the sub-scanning direction in steps S204 and 205. Therefore, in step S206 (and step S210), the distortion is corrected in the main scanning direction.

Further, in this embodiment, in order to effectively suppress the image distortion in the sub-scanning direction by a light calculation load, the data of the data acquisition position located in the sub-scanning direction at the same position on the main scanning direction as the data generation position. Is to be selected. However, regardless of the directionality such as the main scanning direction, the data of at least two sampling points from the one having the shortest distance may be selected from the two fields in which the data is continuously acquired in chronological order. For example, in FIG. 6, the distance in the sub-scanning direction is short with respect to the distance in the main scanning direction of the sampling points, and the sampling points at short distances are limited to points on the same one-point chain line. However, when the distance between the alternate long and short dash lines M1 and M2 is actually closer, for example, the candidates to be selected for obtaining the data at the intersection position P22'are the data of the black circles P12, P13, P33, and P32, and are selected from these. It may be that.

(Other Examples)
In the above-described embodiment, the case where the present invention is used for the SLO device is described, but the ophthalmic device to which the present invention is applied is not limited to this. As described above, in various ophthalmologic imaging devices such as AO-SLO devices and OCT (optical coherence tomography) devices that scan illumination light (measurement light) with the eye to be inspected to acquire data and generate images. Can also be used.

Further, in the above-described examples, the case where the subject is an eye is described, but it is also possible to apply the present invention to a subject such as skin or an organ other than the eye. In this case, the present invention has an aspect as a medical device other than an ophthalmologic imaging apparatus, for example, an endoscope. Therefore, it is preferable that the present invention is grasped as an inspection apparatus exemplified by an ophthalmologic imaging apparatus, and the eye to be inspected is grasped as one aspect of a subject.

The present invention can also be achieved by configuring the device as follows. That is, a recording medium (or storage medium) on which the program code (computer program) of the software that realizes the functions of the above-described embodiment is recorded may be supplied to the system or the device. Further, not only the mode of the recording medium but also a computer-readable recording medium may be used. Then, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the function of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention. The embodiment can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

100: Data acquisition unit 101: System unit 102: Display unit Er: Fundus 2: Galvano scanner 3: Resonant scanner 7: Photodiode 8: SLO light source 9: Correction photodiode 10: Control unit 11: Image generation unit

Claims (11)

A first scanning member that reciprocates the illumination light in the main scanning direction of the subject,
A second scanning member that scans the illumination light at a constant velocity in a sub-scanning direction that intersects the main scanning direction in the subject.
The first scanning member and the second scanning member cause the illumination light to be two-dimensionally scanned in the first field in the data acquisition range of the subject, and the data acquisition range is different from that of the first field. A scanning control means for two-dimensionally scanning the illumination light in two fields,
In each of the first field and the second field, an acquisition position setting means for setting a data acquisition position for acquiring data from the return light of the illumination light from the subject, and
In order to generate data at new positions arranged at equal intervals in the sub-scanning direction, at least two of the data acquisition positions in the first field and the second field in the order closer to the new position. A selection means for selecting the data acquired at the data acquisition position, and
Have a, and an image generating means for generating an image of the object using the data of the new position of the generated from the selected data,
The first scanning member includes a mirror that reflects the illumination light, and the mirror so as to cause acceleration / deceleration in the scanning speed when the mirror reflects the illumination light and scans in the data acquisition range. inspection apparatus according to claim Rukoto such from the member to be driven. The selection means is at least in the order closer to the new position of the data acquisition positions of the first field and the second field arranged in the sub-scanning direction at the same position in the main scanning direction as the new position. The inspection apparatus according to claim 1, wherein the data acquired at the two data acquisition positions is selected. A first scanning member that reciprocates the illumination light in the main scanning direction of the subject,
A second scanning member that scans the illumination light at a constant velocity in a sub-scanning direction that intersects the main scanning direction in the subject.
The first scanning member and the second scanning member cause the illumination light to be two-dimensionally scanned in the first field in the data acquisition range of the subject, and the data acquisition range is different from that of the first field. A scanning control means for two-dimensionally scanning the illumination light in two fields,
A generation position setting means for setting a plurality of data generation positions for image generation, which are arranged at the first interval in the main scanning direction and at the second interval in the sub-scanning direction.
In each of the first field and the second field, an acquisition position setting means for setting a data acquisition position for acquiring data from the return light of the illumination light from the subject, and
A selection means for selecting data acquired at at least two data acquisition positions in the order closer to the set data generation position among the data acquisition positions set in the first field and the second field.
Have a, and an image generating means for generating an image of the object using the data of the data generation position generated by the selected data,
The first scanning member includes a mirror that reflects the illumination light, and the mirror so as to cause acceleration / deceleration in the scanning speed when the mirror reflects the illumination light and scans in the data acquisition range. inspection apparatus according to claim Rukoto such from the member to be driven. The inspection device according to claim 3, wherein the first interval is an interval between the data acquisition positions in the main scanning direction set by the acquisition position setting means. The selection means is at least two of the data acquisition positions arranged in the sub-scanning direction at the same position in the main scanning direction as the data generation position in the order closer to the set data generation position. The inspection apparatus according to claim 3, wherein the data acquired in the above is selected. Any one of claims 1 to 5, wherein the data selected by the selection means is data in the first field and the second field for which data has been continuously acquired in time series. The inspection device described in. It has a detecting means for detecting the amplitude and period of vibration of the first scanning member.
Based on the output of the detection means, the acquisition position setting means sets the data acquisition position so as to be aligned on a straight line extending in the sub-scanning direction in the first field and the second field. The inspection apparatus according to any one of Items 1 to 6 . The inspection device according to any one of claims 1 to 7 , wherein the first scanning member is a resonant scanner. A first scanning member that reciprocates the illumination light in the main scanning direction of the subject,
A second scanning member that scans the illumination light at a constant velocity in a sub-scanning direction that intersects the main scanning direction in the subject.
The first scanning member and the second scanning member cause the illumination light to be two-dimensionally scanned in the first field in the data acquisition range of the subject, and the data acquisition range is different from that of the first field. and scanning control means for two-dimensionally scanning the illumination light in two fields, the possess,
The first scanning member includes a mirror that reflects the illumination light, and the mirror so as to cause acceleration / deceleration in the scanning speed when the mirror reflects the illumination light and scans in the data acquisition range. a method for controlling an inspection apparatus ing from the member to be driven,
A step of setting a data acquisition position for acquiring data from the return light of the illumination light from the subject in each of the first field and the second field.
In order to generate data at new positions arranged at equal intervals in the sub-scanning direction, at least two of the data acquisition positions in the first field and the second field in the order closer to the new position. The process of selecting the data acquired at the data acquisition position and
A control method for an inspection apparatus, which comprises a step of generating an image of the subject using the data of the new position generated from the selected data. A first scanning member that reciprocates the illumination light in the main scanning direction of the subject,
A second scanning member that scans the illumination light at a constant velocity in a sub-scanning direction that intersects the main scanning direction in the subject.
The first scanning member and the second scanning member cause the illumination light to be two-dimensionally scanned in the first field in the data acquisition range of the subject, and the data acquisition range is different from that of the first field. and scanning control means for two-dimensionally scanning the illumination light in two fields, the possess,
The first scanning member includes a mirror that reflects the illumination light, and the mirror so as to cause acceleration / deceleration in the scanning speed when the mirror reflects the illumination light and scans in the data acquisition range. a method for controlling an inspection apparatus ing from the member to be driven,
A step of setting a plurality of data generation positions for image generation, which are arranged at the first interval in the main scanning direction and at the second interval in the sub-scanning direction.
A step of setting a data acquisition position for acquiring data from the return light of the illumination light from the subject in each of the first field and the second field.
A step of selecting data acquired at at least two data acquisition positions in the order closer to the set data generation position among the data acquisition positions set in the first field and the second field.
A control method for an inspection apparatus, which comprises a step of generating an image of the subject using the data of the data generation position generated by the selected data. A program comprising causing a computer to execute each step of the control method of the inspection apparatus according to claim 9 or 10 .

Images