Imaging method, imaging device, automated analyzing device, and positional adjustment method for automated analyzing device

Abstract

In relation to an imaging device, in order to acquire highly accurate three-dimensional information and distance information of an object being measured, regardless of misalignment of the optical axis of the imaging device or changes in the optical characteristics of a variable focus lens, the imaging method of the present invention is configured as follows.　The imaging method includes: a first step for acquiring a captured image of a first subject by means of an imaging unit; a second step for selecting two or more reference points from within the first subject; a third step for acquiring the coordinates of the reference points; a fourth step for acquiring a focus position of the reference points; a fifth step for determining whether misalignment of the optical axis between the first subject and the imaging unit is at most equal to a certain value, on the basis of information relating to an imaging permitted area of the first subject, stored in advance, and the coordinates of the reference points and the focus position obtained in the previous steps; a sixth step for calculating the amount of misalignment of the optical axis of the imaging unit if the misalignment of the optical axis is at most equal to the certain value; a seventh step for acquiring a captured image of a second subject that is to be measured; and an eighth step for acquiring a measurement result image by correcting the captured image of the second subject on the basis of the amount of misalignment of the optical axis.

Description

Imaging method, imaging device, automatic analyzer, and position adjustment method for automatic analyzer

[0001] The present invention relates to an imaging method and imaging device for photographing an object to be measured and calculating a relative position of the object to be measured, and more particularly to an imaging method and imaging device suitable for an automatic analyzer, an automatic analyzer using the same, and a position adjustment method for an automatic analyzer.

[0002] Lenses are used in a variety of optical devices. In addition to general lenses with fixed focal lengths, there are also variable-focus lenses whose focal length can be changed. Variable-focus lenses can adjust the focus faster than focusing by moving the position of the lens itself, and so they are being applied to, for example, automated equipment, inspection equipment, and medical equipment. For example, if a liquid is used as a lens, the focus can be changed by electrically controlling the liquid interface, which forms the refractive surface of the lens, thereby speeding up the focus change. By increasing the speed of focus changes, technological development is underway to measure three-dimensional information and distance information of measured objects using lens focal length information.

[0003] Here, Patent Documents 1 and 2 are known as technologies for measuring three-dimensional information and distance information of a measurement object using a variable-focus lens. Patent Document 1 discloses "a length measuring device comprising: an imaging unit having an imaging lens and imaging a measurement object having a flat surface; a storage unit storing a distance table indicating the relationship between a focus position of the imaging lens and a distance from the imaging lens to the measurement object; a focus position measurement unit measuring the focus position of the imaging lens with respect to three or more reference points set on the flat surface; a distance measurement unit measuring the distance from the imaging lens to each of the reference points based on a comparison result between each of the measured focus positions and the distance table; a coordinate calculation unit calculating spatial coordinates of each of the reference points based on planar coordinates of each of the reference points in an image captured by the imaging unit, the measurement result of the distance measurement unit, and the field of view of the imaging lens; and a dimension information calculation unit determining a reference plane including the flat surface based on the spatial coordinates of each of the reference points and calculating dimensional information on the reference plane."

[0004] Furthermore, Patent Document 2 discloses "a three-dimensional shape measurement device for measuring the three-dimensional shape of an object to be inspected, comprising: an imaging unit which includes a camera which images the object to be inspected, the distance to a focus position of which is constant, and which is a variable imaging distance from the camera to the object to be inspected; an imaging control unit which causes the imaging unit to image the object to be inspected at a plurality of the imaging distances; a focus position calculation unit which acquires each image captured by the imaging unit and calculates a focus position based on a focus degree of each portion of each image; a shape identification unit which calculates a focus distribution which is a set of focus positions based on the focus positions calculated by the focus position calculation unit and identifies the three-dimensional shape of the object to be inspected based on the calculated focus distribution; and a shape extraction unit which calculates features at each position of the three-dimensional shape of the object to be inspected identified by the shape identification unit and extracts a predetermined type of shape which constitutes the three-dimensional shape based on the calculated features."

[0005] JP 2014-115179 A JP 2020-41976 A

[0006] In the method described in Patent Document 1, the distance from the imaging lens to the object to be measured is calculated using the focal position of the imaging lens and a distance table in a storage unit. However, since it is not possible to correct changes in the optical characteristics of the imaging lens over time, there is a possibility that the calculated distance from the imaging lens to the object to be measured will be inconsistent, and the spatial coordinates calculated based on the measurement results of the distance measurement unit and the field of view of the imaging lens may be misread.

[0007] Furthermore, in the method described in Patent Document 2, the object to be inspected is imaged while changing the focus position of the imaging unit, and the three-dimensional shape of the object to be inspected is identified based on the focus distribution of the object to be inspected. However, since the tilt of the surface of the object to be inspected changes due to misalignment of the optical axis caused by play in the installation of the imaging unit of the imaged object to be inspected, there is a possibility that the focus distribution of the object to be inspected may be misread, which may make it difficult to obtain the three-dimensional shape of the object to be inspected.

[0008] The object of the present invention is to provide an imaging method, an imaging device, an automatic analyzer using the same, and a method for adjusting the position of an automatic analyzer that can obtain highly accurate three-dimensional information and distance information of a measured object without being dependent on misalignment of the optical axis of the imaging device or changes in the optical characteristics of a variable-focus lens.

[0009] One aspect for achieving the above object is as follows: an imaging method including: a first step of acquiring a captured image of a first subject by an imaging unit, a second step of selecting two or more reference points from the first subject, a third step of acquiring coordinates of the reference points, a fourth step of acquiring a focus position of the reference points, a fifth step of determining whether a misalignment of the optical axes of the first subject and the imaging unit is equal to or less than a certain value based on pre-stored information about an imaging allowable area of ​​the first subject and the coordinates and focus positions acquired in the fifth step, a sixth step of calculating the amount of misalignment of the optical axis if the misalignment of the optical axis of the imaging unit is equal to or less than the certain value, a seventh step of acquiring a captured image of a second subject that is a measurement target, and an eighth step of correcting the captured image of the second subject based on the amount of misalignment of the optical axis to acquire an image of the measurement result.

[0010] Also, an imaging device is provided that includes a variable-focus lens that changes the focal length, a control unit that controls the focus of the variable-focus lens, a detection unit that detects the in-focus position at the imaging position of the subject using the variable-focus lens, and a measurement unit that measures the relative position of the subject based on the difference between the imaging position of the subject and the in-focus position, and that includes a calculation unit that calculates the misalignment of the optical axis between the first subject and the imaging device based on the imaging position and in-focus position of the first subject, and a correction unit that corrects the measurement result of the relative position of a second subject to be measured based on the information about the misalignment of the optical axis between the first subject and the imaging device calculated by the calculation unit.

[0011] According to the present invention, it is possible to provide an imaging method, an imaging device, an automatic analyzer using the same, and a position adjustment method for an automatic analyzer that can measure the relative positional relationship of multiple objects with high accuracy without relying on misalignment of the optical axis of the imaging device or changes in the optical characteristics of the variable-focus lens.

[0012] FIG. 1 is a diagram illustrating the configuration of an imaging system according to a first embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the configuration of an automatic analyzer to which the imaging system of the present invention can be applied. FIG. 3 is a schematic diagram illustrating the configuration of a dispensing mechanism of an automatic analyzer equipped with an imaging device according to the present invention. FIG. 4 is a flowchart illustrating imaging operations by the imaging system according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating a captured image when capturing an image of a first subject according to the first embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating three directions of misalignment of the optical axis of the imaging unit according to the first embodiment of the present invention. FIG. 7 is a diagram illustrating a captured image reflecting the measurement results of the imaging system according to the first embodiment of the present invention. FIG. 8 is a diagram illustrating the configuration of an imaging system according to a second embodiment of the present invention. FIG. 9 is a flowchart illustrating imaging operations by the imaging system according to the second embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a method for calculating the XY direction distances of the imaging measurement positions of the reference points FP1 and FP2 of the probe according to the second embodiment of the present invention.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. Although the following describes an example of a variable focus lens, a general lens with a fixed focal length can also be applied.

[0014] 1 is a configuration diagram of an imaging system of Example 1. The imaging system 1 includes an imaging device 2 and an image output unit 3 connected to the imaging device and outputting the imaging results.

[0015] The imaging device 2 includes an imaging unit 10 and a control unit 20 .

[0016] The imaging unit 10 includes an imaging element 11, an imaging lens 12, a lens driving unit 13, and a signal processing unit (hereinafter also referred to as an "image processing unit") 14. The imaging element 11 is composed of a PSD (Position Sensitive Detector), a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, or the like, and captures an image of the object to be measured. Strictly speaking, the imaging element 11 receives reflected light from the object to be measured via the imaging lens 12 to capture the image.

[0017] The imaging lens 12 is composed of a lens configured to be able to freely change the focal length, and has a variable-focus lens 15 that moves for focusing and a fixed lens 16 that moves for zoom adjustment. Strictly speaking, the variable-focus lens 15 and the fixed lens 16 each consist of a lens group made up of multiple lenses.

[0018] The lens driver 13 is composed of a one-two phase excitation or microstep stepping motor and a liquid lens driver, and drives the imaging lens 12. Specifically, the lens driver 13 moves the position of the variable-focus lens 15 on the optical axis to perform focus adjustment.

[0019] The image processing unit 14 performs image processing on the captured image acquired by the image sensor 11 to detect a contrast value of the captured image. As will be described in detail later, this contrast value is used to measure the focal position of the variable-focus lens 15 with respect to the object. The control unit 20 includes a storage unit 30, a generation unit 40, and a calculation unit 50.

[0020] The storage unit 30 includes a first object imaging position 31, a first object focusing position 32, a first object imaging allowable area 33, and aberration correction data 34. Here, the first object 1000 is an object whose relative position with respect to the imaging lens 12 is known when there is no misalignment of the optical axis of the imaging unit 10. The first object imaging position 31 is the position of a specific point in the first object that appears in the captured image when there is no misalignment of the optical axis of the imaging unit 10. The first object focusing position 32 is the position at which a specific point in the first object 1000 appears in the captured image when there is no misalignment of the optical axis of the imaging unit 10.

[0021] The first object imaging allowable area 33 is an area in the captured image where a specific point of the first object 1000 exists when the misalignment of the optical axis of the imaging unit 10 is equal to or less than a predetermined value. If there is no misalignment of the optical axis of the imaging unit 10, the specific point of the first object 1000 that appears in the captured image exists at the first object imaging position 31. However, due to misalignment of the optical axis caused by play in the installation of the imaging device, the specific point of the first object 1000 does not actually exist at the first object imaging position 31. In this case, if the optical axis is significantly misaligned and the specific point of the first object exists outside the first object imaging allowable area 33, it becomes impossible to measure the relative position of each object with correction for the misalignment of the optical axis, as will be described later.

[0022] The aberration correction data 34 is data on correction values ​​for distortion aberration (lens distortion) in the imaging lens 12. In other words, it is matrix data consisting of distortion correction values ​​for each X and Y coordinate in the captured image. This aberration correction data 34 is used when correcting lens distortion in the captured image. This aberration correction data 34 is also created by measuring correction values ​​for each X and Y coordinate for each imaging lens 12.

[0023] The generation unit 40 includes a distance table 41. The distance table 41 is a table showing the relationship between the focal position of the variable-focus lens 15 and the distance (depth) from the imaging lens 12 to the object in the optical axis direction. The focal position of the variable-focus lens 15 is the lens position of the variable-focus lens 15 at which a focused image is obtained and the voltage value (referred to as the "number of steps") applied to the lens. The distance table 41 is created by measuring the distance corresponding to each focal position for each imaging lens 12. Furthermore, when there is no misalignment of the optical axis of the imaging unit 10, the relative position between the first object 1000 and the imaging lens 12 is known, and the distance table 41 is generated based on the measurement results of the focal position of the first object 1000.

[0024] The calculation unit 50 includes an imaging position measurement unit 51, a focus position measurement unit 52, a determination unit 53, an optical axis deviation calculation unit 54, a relative coordinate calculation unit 55, and a coordinate correction unit 56. The imaging position measurement unit 51 measures the position of the measurement object in the captured image using the image sensor 11 and the image processing unit 14. Specifically, the image processing unit 14 detects the contour of each measurement object using a brightness difference. The position of the target measurement object is detected from the detected contours using a matching method or the like.

[0025] The focus position measurement unit 52 measures the focus position of the variable-focus lens 15 using the image sensor 11, the lens driver 13, and the image processor 14. Specifically, the lens driver 13 drives the variable-focus lens 15, while the image sensor 11 acquires a captured image at each lens state (step number) of the variable-focus lens 15. The image processor 14 then calculates the focus level based on various calculation methods, such as the absolute value of the luminance gradient within the target region, the variance of luminance, or edge intensity, for a certain region of the captured image. The lens position at which a captured image with a high focus level within the target region is obtained as a result of the calculation is determined to be the focus position. The luminance gradient is calculated based on the difference between the luminance value of each pixel constituting the image within the target region and the luminance values ​​of one or more of the adjacent pixels, for example. Various calculation methods are available, and any of them can be used as appropriate.

[0026] The determination unit 53 determines whether the deviation of the optical axis of the imaging unit 10 is equal to or less than a certain value based on the measurement result of the imaging position measurement unit 51 and the first object imaging allowable area 33 .

[0027] The optical axis deviation calculation unit 54 calculates the deviation in the relative position between the imaging unit 10 and the first object 1000 based on the measurement results of the imaging position measurement unit 51, the measurement results of the focus position measurement unit 52, the first object imaging position 31, and the first object focus position 32, and calculates the deviation of the optical axis of the imaging unit 10, etc.

[0028] The relative coordinate calculation unit 55 calculates the relative coordinates of the object to be measured in the optical axis direction as seen from the imaging lens 12 based on the measurement results of the imaging position measurement unit 51, the measurement results of the focusing position measurement unit 52, the aberration correction data 34, and the distance table 41.

[0029] The coordinate correction unit 56 measures the relative coordinates of the object to be measured as seen from the imaging lens 12 in the optical axis direction, taking into account the misalignment of the optical axis of the imaging unit 10, based on the measurement results of the relative coordinate calculation unit 55, the measurement results of the optical axis deviation calculation unit 54, and the aberration correction data 34.

[0030] FIG. 2 is a schematic diagram of an automatic analyzer, which is one of the applications of the imaging system 1 of this embodiment. The automatic analyzer 100 is an apparatus for measuring a reaction liquid that has undergone a chemical reaction in a reaction vessel 102 and analyzing its components. This automatic analyzer 100 primarily includes a reaction disk 101, a cleaning mechanism 103, a spectrophotometer 104, a stirring mechanism 105, a cleaning tank 106, a reagent dispensing mechanism 107, a cleaning tank 108, a reagent disk 109, a pair of sample dispensing mechanisms 111 (in FIG. 2 , reference numeral 111 is only attached to the sample dispensing mechanism on the left side of the drawing, but the same sample dispensing mechanism is also attached to the right side of the drawing), a cleaning tank 113, a sample transport mechanism 117, and a controller 118. Furthermore, the reagent dispensing mechanism 107 and the sample dispensing mechanism 111 each have a liquid level detection function.

[0031] A plurality of reaction vessels 102 are arranged on the circumference of the reaction disk 101. The reaction vessels 102 are containers for containing a mixture of a sample and a reagent. A sample transport mechanism 117 is arranged near the reaction disk 101 to transport a sample rack 116 loaded with sample vessels 115.

[0032] A pair of sample dispensing mechanisms 111 that can rotate and move up and down are disposed between the reaction disk 101 and the sample transport mechanism 117. Each of the pair of sample dispensing mechanisms 111 includes a sample dispensing arm 111a and a sample dispensing probe 111b. A sample syringe 122 is connected to each of the sample dispensing probes 111b. The sample dispensing probe 111b moves horizontally while drawing an arc around the rotation axis, and moves up and down to dispense samples from sample containers 115 to reaction containers 102. The reagent disk 109 is a storage cabinet in which multiple reagent bottles 110 containing reagents, detergent bottles 112, etc. can be placed on its circumference. The reagent disk 109 is kept cold.

[0033] A pair of reagent dispensing mechanisms 107 that can rotate and move up and down are installed between the reaction disk 101 and the reagent disk 109, and each mechanism includes a reagent dispensing arm 107a and a reagent dispensing probe 120. The reagent dispensing probe 120 is moved up and down and horizontally by the reagent dispensing mechanism 107. Reagent syringes 121 are connected to the reagent dispensing probes 120, respectively. The reagent syringes 121 dispense reagents, detergents, diluents, pretreatment reagents, etc., aspirated from reagent bottles 110, detergent bottles 112, diluent bottles, pretreatment reagent bottles, etc., via the reagent dispensing probes 120 into reaction vessels 102.

[0034] Around the reaction disk 101, there are arranged a cleaning mechanism 103 for cleaning the inside of the reaction vessel 102, a spectrophotometer 104 for measuring the absorbance of light that passes through the mixed liquid in the reaction vessel 102, a stirring mechanism 105 for mixing the sample and reagent dispensed into the reaction vessel 102, and the like.

[0035] In addition, a washing tank 108 for the reagent dispensing probe 120 is located within the operating range of the pair of reagent dispensing mechanisms 107, a washing tank 113 for the sample dispensing probe 111b is located within the operating range of the pair of sample dispensing mechanisms 111, and a washing tank 106 for the stirring mechanism 105 is located within the operating range of the stirring mechanism 105.

[0036] Each mechanism is connected to a controller 118, and its operation is controlled by the controller 118. The controller 118, which serves as a control section, is composed of a computer or the like, and controls the operation of each mechanism described above within the automatic analyzer, as well as performing calculations to determine the concentration of a predetermined component in a liquid sample such as blood or urine.

[0037] The analysis process of a test sample by the above-described automatic analyzer 100 is performed in the following order: First, a sample in a sample container 115 placed on a sample rack 116 transported by the sample transport mechanism 117 to the vicinity of the reaction disk 101 is dispensed into a reaction container 102 on the reaction disk 101 by the sample dispensing probe 111b of one of the pair of sample dispensing mechanisms 111. Next, a reagent to be used for the analysis is dispensed from a reagent bottle 110 on the reagent disk 109 by one of the pair of reagent dispensing mechanisms 107 into the reaction container 102 into which the sample was previously dispensed. Next, the mixing mechanism 105 mixes the mixture of the sample and reagent in the reaction container 102.

[0038] Thereafter, light generated from the light source is irradiated onto and transmitted through the reaction vessel 102 containing the mixed solution, and the luminous intensity of the transmitted light is measured by the spectrophotometer 104. The luminous intensity measured by the spectrophotometer 104 is sent to the controller 118 via an A / D converter and an interface. The controller 118 then performs calculations to determine the concentration of a predetermined component in a liquid sample such as blood or urine, and displays the result on a display unit (not shown) or the like. Note that, although an automatic analyzer that determines the concentration of a predetermined component using the spectrophotometer 104 will be described as an example, the technology disclosed in the embodiments described below may also be used in automatic immunoanalyzers or automatic coagulation analyzers that measure samples using other photometers.

[0039] Fig. 3(a) is a side view of the sample dispensing mechanism 111 to which the imaging device 2 is attached. The sample dispensing mechanism 111 has an arm 111a, a probe 111b, and a shaft 111c. The base end of the probe 111b is held at one end of the arm 111a. In Fig. 3(a), the arm 111a is supported by the shaft 111c. The shaft 111c is configured to be rotatable and movable up and down by a motor (not shown).

[0040] As shown in Figure 3(a), in this specification, the longitudinal direction of the shaft 111c is defined as the up-down direction. The direction parallel to the longitudinal direction of the arm 111a is defined as the front-rear direction, with F representing the front and B representing the rear. The optical axis of the imaging unit 10, i.e., the line passing through the center of the imaging element 11 and the principal point of the imaging lens 12, is defined as O. If there is no misalignment of the optical axis due to looseness in the installation of the imaging device 2, the optical axis O of the imaging unit 10 will be on the same line as the tip of the probe.

[0041] 3B is a rear view of the periphery of the imaging device 2 as seen from behind. As shown in FIG. 3B, in this embodiment, the short direction of the arm 111a (the direction perpendicular to the up-down and front-rear directions) is the left-right direction, with right represented as R and left as L. A is a plane including the rotation axis Q of the arm 111a and the central axis of the probe 111b. P is a plane including the center of the imaging element 11 and the central axis of the probe 111b. If there is no play in the installation of the imaging device 2 or the probe 111b, then plane A and plane P are the same.

[0042] FIG. 4 is a flowchart showing the imaging operation of the imaging system in Example 1. When the process starts, the imaging device 2 first captures an image of a first object using the imaging unit 10 to obtain a captured image of the first object. In this example, the probe 111b shown in FIG. 5 is the first object. (Step S101) In step S102, two or more reference points are selected within the probe 111b present in the captured image 200. The reference points can be manually specified by the operator using the captured image 200, or can be selected from the captured image 200 output by the imaging device 2 based on conditions previously set in the imaging device 2. In this example, the tip position FP1 of the probe 111b shown in FIG. 5 and the upper end center point FP2 of the probe 111b in the captured image 200 are used as reference points.

[0043] In step S103, the image capture unit 10 measures the coordinates of the image capture positions of the reference points FP1 and FP2 of the first object. Specifically, for the captured image 200 in FIG. 5, the signal processing unit 14 detects contours using brightness differences. The contour of the first object is detected from the detected contours using a matching method or the like. The Y-coordinates of FP1 and FP2 are obtained by acquiring the upper and lower ends of the detected contour of the first object. The X-coordinates of the contours around the Y-coordinates of FP1 and FP2 are averaged to identify the center position, thereby acquiring the X-coordinates of FP1 and FP2.

[0044] In step S104, the image capture unit 10 measures the in-focus positions of the reference points FP1 and FP2 of the first subject. Specifically, the lens drive unit 13 drives the variable-focus lens 15, while the image capture element 11 acquires a captured image at each lens position of the variable-focus lens 15 (the number of steps of the stepping motor of the lens drive unit 13 corresponds to each lens position). The image processor (signal processor) 14 then detects the contrast value of each captured image at each lens position. The lens position at which the captured image with the maximum contrast value is obtained as a result of the detection is determined to be the in-focus position.

[0045] In step S105, the control unit 20 determines whether the optical axis deviation of the image capturing unit 10 is equal to or less than a certain value based on the first object imaging allowable area 33 in the memory unit 30, the imaging position measurement unit 51, the focus position measurement unit 52, and the determination unit 53 in the calculation unit 50. In this embodiment, the control unit 20 determines whether the tip FP1 of the probe 111b shown in FIG. 5 is present within the first object imaging allowable area 201. The control unit 20 also determines whether the difference between the focus position of the tip FP1 of the probe 111b measured in step S104 and the first object focus position 32 in the memory unit 30 is equal to or less than a certain value. If the optical axis deviation of the image capturing unit 10 is equal to or less than the certain value, the control unit 20 proceeds to step S106. If the optical axis deviation of the image capturing unit 10 is equal to or greater than the certain value, the control unit 20 notifies the image output unit 3 that the imaging environment of the image capturing device 2 is abnormal (step S107), and subsequent measurements are discontinued.

[0046] In step S106, the control unit 20 calculates the misalignment of the optical axis of the imaging unit 10 based on the first object imaging position 31, the first object focusing position 32, the aberration correction data 34, the imaging position measurement unit 51, the focusing position measurement unit 52, and the optical axis misalignment calculation unit 54 of the calculation unit 50. In this embodiment, the tilt of the imaging device 2 in the roll direction 300, the yaw direction 400, and the pitch direction 500 relative to the sample dispensing mechanism 111 shown in FIG. 6 is defined as the misalignment of the optical axis of the imaging unit 10. The distances (ΔX, ΔY) in the X and Y directions between the reference points FP1 and FP2 of the probe 111b are calculated using the pixel difference in the X direction and the pixel difference in the Y direction between the imaging measurement positions of the reference points FP1 and FP2 of the probe 111b shown in FIG. 5. The tilt of the imaging device 2 in the roll direction 300 is calculated using the calculated distances. Next, using the pixel difference in the X direction between the reference point FP1 of the probe 111b and the first object imaging position 202 in the storage unit, the distance in the X direction between the reference point FP1 of the probe 111b and the first object imaging position 202 is calculated. The tilt in the yaw direction 400 is calculated using the calculated distance in the X direction and the tilt in the roll direction 300 calculated above.

[0047] Finally, using the pixel difference in the X direction between the reference point FP1 of the probe 111b and the first object imaging position 202 in the storage unit, the distance in the Y direction between the reference point FP1 of the probe 111b and the first object imaging position 202 is calculated. The tilt in the pitch direction 500 is calculated using the calculated distance in the Y direction and the tilt in the roll direction 300 calculated above.

[0048] In step S108, the generation unit 40 generates a distance table 41 indicating the correlation between the distance from the variable-focus lens 15 and the imaging lens, based on the focus position measurement unit 52 and the optical axis deviation calculation unit 54 of the calculation unit 50. In this embodiment, the distance table 41 is generated using the difference between the focus measurement positions of the reference points FP1 and FP2 of the probe 111b shown in FIG. 5 and the deviation of the optical axis of the imaging unit 10 calculated in step S106.

[0049] In step S109, the control unit 20 calculates the relative coordinates of the measurement point of the first object as seen from the imaging lens 12 based on the aberration correction data 34 in the storage unit 30, the distance table 41 of the generation unit 40, the imaging position measurement unit 51, the focus position measurement unit 52, and the relative coordinate calculation unit 55 of the calculation unit 50. The measurement point can be manually specified by the operator using the captured image, or can be selected from the captured image output by the imaging device 2 based on conditions previously set in the imaging device 2. In this embodiment, the tip position of the probe 111b shown in FIG. 5 is set as the measurement point MP1.

[0050] In step S110, the imaging device 2 captures an image of the second object by using the imaging unit 10. In this embodiment, the second object is a cylindrical object shown in FIG.

[0051] In step S111, the imaging unit 10 and the imaging position measurement unit 51 of the calculation unit 50 of the control unit 20 measure the imaging position of the measurement target point of the second object. The measurement target point can be manually specified by the operator using the captured image, or selected from the captured image output by the imaging device 2 based on conditions previously set in the imaging device 2. In this embodiment, the center MP2 of the upper surface of the cylindrical object is set as the measurement target point of the second object. Specifically, for the captured image 200 in FIG. 7, the signal processing unit 14 detects the contour using brightness difference. The contour of the second object is detected from the detected contour using a matching method or the like. The upper surface of the second object is detected by detecting a circle from the detected contour of the second object. The measurement target point of the second object is obtained by extracting the center of the detected upper surface of the second object.

[0052] In step S112, the imaging unit 10 and the focus position measurement unit 52 of the calculation unit 50 of the control unit 20 measure the imaging position of the measurement target point of the second subject. Specifically, while the lens driving unit 13 drives the variable-focus lens 15, the image processing unit 14 acquires the lens position at which a captured image having the maximum contrast value is obtained at the measurement target point of the second subject.

[0053] In step S113, the control unit 20 calculates the relative coordinates of the measurement target points of the second object as seen from the measurement target points of the first object, based on the aberration correction data 34 of the storage unit 30, the distance table 41 of the generation unit 40, the imaging position measurement unit 51, the focus position measurement unit 52, and the relative coordinate calculation unit 55 of the calculation unit 50. Specifically, first, the control unit 20 calculates the relative coordinates of the measurement target points of the second object as seen from the imaging lens 12, based on the aberration correction data 34 of the storage unit 30, the distance table 41 of the generation unit 40, the imaging position measurement unit 51, the focus position measurement unit 52, and the relative coordinate calculation unit 55 of the calculation unit 50. The control unit 20 acquires the relative coordinates of the measurement target points of the second object as seen from the measurement target points of the first object, based on the calculated relative coordinates and the relative coordinates of the measurement target points of the first object as seen from the imaging lens 12 calculated in step S109.

[0054] In step S114, the control unit 20, based on the relative coordinate calculation unit 55 of the calculation unit 50 and the coordinate correction unit, corrects the relative coordinates of the measurement point of the second subject as viewed from the measurement point of the first subject calculated in step S113 using the shift in the optical axis of the imaging unit 10 calculated in step S106, and calculates relative coordinates that take the shift in the optical axis into account.

[0055] In step S115, the imaging device 2 outputs the relative coordinate results of the measurement target points of the first subject and the measurement target points of the second subject calculated by the calculation unit 50 in the control unit 20 as measurement results to the image output unit 3. The relative coordinates of the measurement target points of the first subject and the second subject as seen from the imaging lens 12, and the relative coordinates of the measurement target points of the second subject as seen from the measurement target points of the first subject, are output to the image output unit 3. This completes the imaging operation.

[0056] In Example 1, the deviation of the optical axis of the imaging unit 10 was measured based on the imaging position and focus position of the reference point of the first object. However, it is also possible to measure the deviation of the optical axis of the imaging unit 10 based on dimensional information of the reference point of the first object. FIG. 8 is a configuration diagram of an imaging system in Example 2. Only differences from the imaging system of Example 1 will be described. The imaging device 2 in this example includes first object dimension information 35 in the memory unit 30 of the control unit 20. The first object dimension information 35 is data related to the dimension between two or more predetermined reference points of the first object when there is no deviation of the optical axis of the imaging unit 10 relative to the first object. The imaging device 2 also includes a first object dimension measurement unit 57 in the calculation unit 50 of the control unit 20. The first object dimension measurement unit 57 measures the dimension between two or more reference points of the first object when the imaging device 2 actually images the first object.

[0057] 9 is a flowchart showing the imaging operation when measuring the deviation of the optical axis of the imaging unit 10 based on the imaging position and dimensional information of the first subject. Only the parts different from the first embodiment will be described.

[0058] In step S204, the calculation unit 50 uses the first object dimension measurement unit to measure the dimensions of two reference points in the probe 111b present in the captured image. As shown in Fig. 10, the length L of the two points is measured using the pixel difference between the two reference points FP1 and FP2 of the probe 111b present in the captured image.

[0059] In step S206, the control unit 20 calculates the optical axis deviation of the imaging unit 10 based on the first object imaging position 31, first object focusing position 32, aberration correction data 34, first object dimension information 35, and the imaging position measurement unit 51, first object dimension measurement unit, and optical axis deviation calculation unit 54 of the calculation unit 50 in the storage unit 30. The distances (ΔX, ΔY) in the X and Y directions between the reference points FP1 and FP2 of the probe 111b are calculated using the pixel difference in the X direction and the pixel difference in the Y direction between the imaging measurement positions of the reference points FP1 and FP2 of the probe 111b shown in FIG. The tilt of the imaging device 2 in the roll direction 300 is calculated using the calculated distances.

[0060] Next, the distance in the X direction between the reference point FP1 of the probe 133 and the first object imaging allowable area 201 of the storage unit is calculated using the pixel difference in the X direction between the reference point FP1 of the probe 133 and the first object imaging allowable area 201. The tilt in the yaw direction 400 is calculated using the calculated distance in the X direction and the tilt in the roll direction 300 calculated above. Finally, the tilt in the pitch direction 500 is calculated based on the dimension L related to the reference points FP1 and FP2 of the probe 111b measured by the first object dimension measurement unit 57 of the calculation unit 50 in the control unit 20, the dimensional information of the reference points FP1 and FP2 of the probe 111b stored in the aberration correction data 34 of the storage unit 30, and the tilt in the roll direction 300 calculated above.

[0061] According to the configurations of the above embodiments, the imaging positions of two reference points set on the probe 111b, which is a first object whose relative position with respect to the imaging device is known, are calculated, and information regarding the misalignment of the optical axis of the imaging unit 10 relative to the first object is calculated based on the calculated optical axis misalignment and the focal position of the reference point. A distance table between the variable-focus lens value and the optical axis depth information is generated based on the calculated optical axis misalignment and the focal position of the reference point. Spatial coordinates are calculated based on the imaging position measured by the imaging device, the optical axis misalignment of the imaging unit, and the generated distance table. In this way, when there is no optical axis misalignment or the like in the imaging device, the relative position between the imaging unit 10 and the first object is known, and information regarding the misalignment of the optical axis of the imaging unit 10 and the optical characteristics of the variable-focus lens is calculated, and the calculated information and the results of the imaging device are used to calculate spatial coordinates. Therefore, accurate spatial coordinates can be obtained without relying on the misalignment of the optical axis of the imaging unit due to installation play of the imaging device. Furthermore, degradation in the measurement accuracy of spatial coordinates due to changes in the optical characteristics of the variable-focus lens over time can be suppressed.

[0062] In particular, by attaching an imaging unit to the dispensing arm of an automated analyzer, it is possible to accurately measure the relative positional relationship between the dispensing probe and the container (reagent container, sample container, reaction container, washing tank, etc.) into which the dispensing probe dispenses reagents, samples, etc. This allows the dispensing probe to accurately dispense various liquids to predetermined positions. It also makes it possible to accurately and quickly adjust the relative positional relationship between the dispensing probe and the container into which the dispensing probe dispenses reagents, samples, etc.

[0063] 1...imaging system, 2...imaging device, 3...image output unit, 10...imaging unit, 11...imaging element, 12...imaging lens, 13...lens driving unit, 14...signal processing unit, 15...variable focus lens, 16...fixed lens, 20...control unit, 30...storage unit, 31...first object imaging position, 32...first object focusing position, 33...first object imaging allowable area, 34...aberration correction data, 35...first object dimension information, 40...generation unit, 41...distance table, 50...calculation unit, 51...imaging position measurement unit, 52...focus position measurement unit, 53...determination unit, 54...optical axis deviation calculation unit, 55...relative coordinate calculation unit, 56...coordinate correction unit, 57...first object dimension measurement unit, 100...automatic analysis device, 101 ...reaction disk, 102...reaction vessel, 103...cleaning mechanism, 104...spectrophotometer, 105...stirring mechanism, 106...cleaning tank (for stirring mechanism), 107...reagent dispensing mechanism, 107a...reagent dispensing arm, 108...cleaning tank (for reagent dispensing mechanism), 109...reagent disk, 110...reagent bottle, 111...first sample dispensing mechanism, 111a...sample dispensing arm, 111b...sample dispensing probe, 112...detergent bottle, 113...cleaning tank (for sample dispensing mechanism), 115...sample container, 116...sample rack, 117...sample transport mechanism, 118...controller, 120...reagent dispensing probe, 200...captured image, 201...first subject imaging permitted area, 210...second subject.

Claims

1. An imaging method comprising: a first step of acquiring an image of a first subject by an imaging unit; a second step of selecting two or more reference points from the first subject; a third step of acquiring the coordinates of the reference points; a fourth step of acquiring the focus position of the reference points; a fifth step of determining whether a misalignment of the optical axis between the first subject and the imaging unit is equal to or less than a certain value based on pre-stored information on an imaging allowable area of ​​the first subject and the coordinates and focus position of the reference points acquired in the fifth step; a sixth step of calculating an amount of misalignment of the optical axis if the misalignment of the optical axis of the imaging unit is equal to or less than a certain value; a seventh step of acquiring an image of a second subject to be measured; and an eighth step of acquiring an image of the measurement result by correcting the image of the second subject based on the amount of misalignment of the optical axis.

2. An imaging method according to claim 1, wherein the lens of the imaging unit is a variable focus lens, and instead of calculating the amount of misalignment of the optical axis in the sixth step, the optical characteristics of the variable focus lens are calculated based on pre-stored information on the first subject imaging allowable area and the coordinates of the reference point and the focus position obtained in the sixth step, and the image of the second subject is corrected based on the optical characteristics of the variable focus lens in the eighth step instead of correcting the image of the second subject based on the amount of misalignment of the optical axis.

3. An imaging method according to claim 1, further comprising a notification step of notifying the user that, if the deviation of the optical axis between the first subject and the imaging unit in the fifth step is greater than a certain value, the imaging method further comprises: a step of notifying the user that a deviation of the optical axis between the first subject and the imaging unit is greater than a certain value.

4. An imaging device comprising: a variable focus lens which changes the focal length; a control unit which controls the focus of the variable focus lens; a detection unit which detects a focus position at an imaging position of a subject using the variable focus lens; and a measurement unit which measures a relative position of the subject based on a difference between the imaging position of the subject and the focus position, wherein the imaging device further comprises: a calculation unit which calculates a misalignment of the optical axis between a first subject and the imaging device based on the imaging position and the focus position of the first subject; and a correction unit which corrects a measurement result of the relative position of a second subject to be measured based on information about the misalignment of the optical axis between the first subject and the imaging device calculated by the calculation unit.

5. An imaging device according to claim 4, characterized in that the calculation unit calculates the optical characteristics of the variable focus lens in place of the misalignment of the optical axis, and a correction unit corrects the measurement results of the relative position of the second subject to be measured based on the information on the optical characteristics of the variable focus lens calculated by the calculation unit.

6. An imaging device according to claim 4, further comprising: a determination unit for determining whether the first subject is present within a range of a predetermined imaging position and / or focusing position.

7. An imaging device according to claim 4, further comprising: a notification unit which notifies the user when the first subject is not present within a range of a predetermined imaging position and / or focusing position.

8. An imaging device according to claim 4, further comprising: a memory section for storing the imaging position and the focus position of the first subject when there is no misalignment between the optical axis of the first subject and the imaging device.

9. An imaging device according to claim 4, further comprising: a generating unit that generates a distance table that holds the correlation between the focal length of the variable focus lens when the imaging device is in focus on the first subject and the relative distance from the imaging device to the first subject.

10. An imaging device according to claim 4, further comprising: a memory unit for storing aberration correction data that maintains a correlation between an imaging position acquired by the imaging device and a relative position with respect to an optical axis of the imaging device, based on the optical characteristics of the imaging device.

11. An imaging device as described in claim 4, comprising: a memory unit which stores the imaging position and the focus position of the first subject when there is no misalignment between the optical axes of the first subject and the imaging device; and a generation unit which generates a distance table which maintains the correlation between the focal length of the variable focus lens and the relative distance from the imaging device to the first subject when the imaging device is at the focus position of the first subject; and a correction unit which corrects the measurement result of the relative position between the imaging device and the subject based on the generation unit, the distance table acquired by the memory unit, and the aberration correction data.

12. An automatic analyzer comprising a dispensing probe for dispensing liquid, a dispensing arm to which the dispensing probe is attached, and a liquid container for ejecting liquid from the dispensing probe, wherein at least the imaging unit of the imaging device described in any one of claims 4 to 11 is attached to the dispensing arm.

13. A method for adjusting the position of an automatic analyzer comprising a dispensing probe for dispensing liquid, a dispensing arm to which the dispensing probe is attached, and a liquid container from which liquid is ejected from the dispensing probe, the method comprising adjusting the position of at least the dispensing probe based on results obtained by an imaging method according to any one of claims 1 to 3.

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