Atomic absorption photometer

Abstract

An atomic absorption photometer (1) is provided with: a sample collection unit (24) having a tip (25) for collecting and discharging a sample; an opening (14) for injecting the sample is formed in the upper surface of the sample heating part (11); a movement mechanism (27) that moves the sample collection unit between a first position at which the sample is collected to the tip and a second position at which the sample is injected from the tip to the opening; a light irradiation unit (29) that irradiates the opening with light from a predetermined direction; and an image acquisition unit (26) that captures an image of the opening from an optical axis direction different from the central axis of the light irradiated by the light irradiation unit.

Description

Technical Field

[0001] The invention relates to an atomic absorption photometer. Background Art

[0002] In order to quantify the amount of metals and other elements contained in a liquid sample such as drinking water, an atomic absorption spectrophotometer is used (for example, Patent Document 1). In an atomic absorption spectrophotometer, a liquid sample is thermally decomposed to generate atomic vapor, and the atomic vapor is irradiated with light to measure absorbance.

[0003] The atomic absorption spectrophotometer includes a measuring part and an automatic sampler. The measuring part includes: a sample heating part; a light source for irradiating light to the atomic vapor generated by the sample heating part; and a detector for detecting the light passing through the atomic vapor, and a sample injection part for injecting a liquid sample is provided in the sample heating part. The automatic sampler includes: a sample loading part, provided with a plurality of sample containers containing liquid samples; a tubular tip for collecting liquid samples from the sample container; an arm, the tip being installed at the front end; and a moving mechanism for moving the arm between a sample collection position and a sample injection position. During analysis, the tip installed on the arm of the automatic sampler is inserted into the interior of the sample container to collect the liquid sample, and the tip is moved and inserted into the sample injection part to inject the liquid sample into the sample heating part. As for the sample heating part, in most cases, a graphite furnace having an opening on the upper surface as a sample injection part can be used.

[0004] In the case of such an automatic sampler, the tip deteriorates during repeated use, resulting in an error in the injection amount of the sample, or the tip is clogged and the previously measured liquid sample remains in the tip, resulting in contamination. In order to prevent these situations, the analyst needs to replace the tip at an appropriate time. In addition, since the sample heating part also deteriorates during repeated use, the analyst replaces the sample heating part at an appropriate time. At this time, since the analyst replaces the tip or the sample heating part by manual operation, installation errors such as the tip being installed on the arm in an inclined state or the installation position of the sample heating part being misaligned may occur. In an atomic absorption spectrophotometer, for example, the size of the opening of the sample injection part is 1.8 mm in diameter, the outer diameter of the tip is 1.5 mm, and the error allowed on both sides of the tip in the radial direction is very small and is less than 0.15 mm. If the installation error is greater than this, the tip will contact the sample injection part. Therefore, in the past, after replacing the tip, it was necessary to perform a task called teaching to adjust the movement control of the arm in such a way that the front end of the tip is located directly above the sample injection part. Patent Documents 2 and 3 describe that an image acquired by a camera disposed at a position that simultaneously captures both the tip of the tip and the sample injection portion is displayed on a monitor, and an analyst performs teaching while checking the image.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Utility Model Registration No. 3127657

[0008] Patent Document 2: International Publication No. 2021 / 124513

[0009] Patent Document 3: Japanese Patent Application Publication No. 2012-32310 Summary of the invention

[0010] Problems to be solved by the invention

[0011] When teaching, the sample injection part is photographed by a camera, and while the image is confirmed, the tip is brought to the correct position relative to the opening of the sample injection part. However, in the atomic absorption spectrophotometer, in order to prevent heat from escaping from the sample heating part, the part other than the vicinity of the sample injection part is covered by a heat insulating member. In addition, the light source and the detector arranged across the sample heating part are also covered by a light shielding member. Furthermore, as mentioned above, the sample heating part is a graphite furnace, and its surface is black. Therefore, even if an image is observed by photographing the surface of the graphite furnace in a dark place covered by a heat insulating member or a light shielding member, it is difficult to know the position of the opening provided on the surface, and there is a problem that it is difficult to align the tip with the correct position relative to the opening.

[0012] The problem to be solved by the present invention is to provide a technology that can easily align a tip with a correct position relative to an opening of a sample injection portion provided in a sample heating portion of an atomic absorption spectrophotometer.

[0013] Technical means of solving problems

[0014] The atomic absorption spectrophotometer of the present invention, which is designed to solve the above-mentioned problems, comprises:

[0015] The sample collection part is equipped with a sharp nozzle for collecting and ejecting the sample;

[0016] A sample heating part, the upper surface of which is provided with an opening for injecting the sample;

[0017] a moving mechanism for moving the sample collecting portion between a first position for collecting the sample into the tip and a second position for injecting the sample from the tip into the opening;

[0018] a light irradiation unit that irradiates light toward the opening from a predetermined direction; and

[0019] The image acquisition unit captures an image of the opening from an optical axis direction different from a central axis of the light irradiated by the light irradiation unit.

[0020] Effects of the Invention

[0021] In the case of the atomic absorption photometer of the present invention, the light irradiation unit irradiates light from a predetermined direction to the opening provided on the upper surface of the sample heating unit, and the image acquisition unit photographs the opening from an optical axis direction different from the optical axis of the light irradiation unit. In the case of the atomic absorption photometer of the present invention, since an image with a light-dark contrast produced at the periphery of the opening of the sample heating unit is acquired using the light irradiation unit and the image acquisition unit having mutually different optical axes, the position of the opening can be easily confirmed, thereby aligning the tip with the correct position. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [ Figure 1 ] is a schematic structural diagram of an embodiment of the atomic absorption spectrophotometer of the present invention.

[0023] [ Figure 2 ] is a diagram illustrating the positional relationship among the opening, camera, LED, etc. in the atomic absorption spectrophotometer of this embodiment.

[0024] [ Figure 3 ] is a diagram illustrating the relationship between the area illuminated by light from the LED and the field of view of the camera in this embodiment.

[0025] [ Figure 4 ] is a flow chart of the order of determining the center position of the opening and the front end position of the pointed nozzle in this embodiment.

[0026] [ Figure 5 ] is an example of extracting the area including the tip of the sharp mouth in this embodiment.

[0027] [ Figure 6 ] is an example of obtaining the outline of a partial image of the tip of the sharp mouth in this embodiment.

[0028] [ Figure 7 ] is an example of finding the intersection of the outline of the tip and the center line of the tip in this embodiment.

[0029] [ Figure 8 ] is an example of the result of determining the tip position of the pointed nozzle in this embodiment.

[0030] [ Fig. 9 ] is an example of extracting an edge from a partial image of an area including an opening in this embodiment.

[0031] [ Fig.10 ] is a diagram illustrating the Hough transform.

[0032] [ Fig.11 ] is an example of an area where an opening is extracted in this embodiment.

[0033] [ Fig.12 ] is an example of the result of determining the center position of the opening in this embodiment.

[0034] [ Fig.13 ] is a modified example of determining the tip position of the pointed nozzle. DETAILED DESCRIPTION

[0035] The following describes an embodiment of the atomic absorption spectrophotometer of the present invention with reference to the accompanying drawings. In addition, in the drawings described below, in order to easily show the structure of the main parts, the drawings are shown at a different scale from the actual ones, or the drawings of some components are omitted.

[0036] Figure 1 1 is a schematic diagram of the atomic absorption spectrophotometer 1 of this embodiment. The atomic absorption spectrophotometer 1 is roughly composed of an analysis unit 3 including a measurement unit 10 and an automatic sampler 20 , and a control / processing unit 4 .

[0037] The measuring section 10 includes: a sample heating section 11; a light source 12 for irradiating light to the atomic vapor generated by the sample heating section 11; and a detector 13 for detecting the light that has passed through the atomic vapor. The sample heating section 11 is a cylindrical electric heating furnace with openings on the left and right, and an opening 14 serving as a sample injection section is provided in the center of the upper surface. The size of the sample heating section 11 of the present embodiment is, for example, 5 mm in diameter and 2 cm in length, and the diameter of the opening 14 is, for example, 1.8 mm. In the optical path from the light source 12 to the detector 13, the portion after excluding the vicinity of the opening 14 of the sample heating section 11 is covered by a light shielding / heat insulating member 15 for light shielding and heat insulation.

[0038] The automatic sampler 20 includes a turntable 21 provided with a plurality of sample containers 22 containing liquid samples, an arm 24 having a tip 25 mounted on the lower surface of the front end thereof for collecting liquid samples from the sample containers 22, and a shaft member 23 rotatably mounted at the base end of the arm 24. The automatic sampler 20 is provided with a moving mechanism 27 for rotating the shaft member 23 or moving the shaft member 23 in a horizontal plane and in a vertical direction.

[0039] The moving mechanism 27 is configured to enable the arm 24 equipped with the tip 25 to move to a first position ( Figure 1 ), and a second position (a position indicated by a two-dot chain line in FIG. 1 ) at which the liquid sample is injected into the opening 14 of the sample heating portion 11. Figure 1 The position indicated by the dotted line in the figure), and a third position different from the first position and the second position ( Figure 1). Regarding the third position, a place is selected where the contrast with the background is large when the tip 25 is photographed. The arm 24 is moved to the first position, and the tip 25 is moved vertically downward to collect the sample in the sample container 22, and then the arm 24 is moved to the second position, and the tip 25 is moved vertically downward to inject the sample into the opening 14. The outer diameter of the tip 25 used in this embodiment is, for example, 1.5 mm. The tip 25 in this embodiment is tubular (hollow rod), but it can also be other shapes. Furthermore, regarding the second position, the arm 24 can also be moved to a position that is offset by a predetermined length in a predetermined direction from the position when the sample is sampled. In the following, the position when the tip 25 is arranged directly above the opening 14 of the sample heating section 11 and the sample is injected is also referred to as the sample injection position, and the position after the tip 25 is offset (shifted) by a predetermined distance in the horizontal direction and / or the height direction from directly above the opening 14 is also referred to as the offset position. The offset position is used when photographing the opening 14 of the sample heating unit 11 with the tip 25 mounted on the arm 24. The photography will be described later. In addition, it is not necessary for the present invention to move the arm 24 to the third position. When photographing the tip 25 at the offset position to determine the tip 25 front end position, the third position may not be set.

[0040] like Figure 2 As shown in FIG. 1 , a camera 26 is mounted on the lower surface of the arm 24 closer to the base than the tip 25. In addition, a light emitting diode (LED) 29 is mounted on the lower surface of the arm 24 closer to the front end than the tip 25. Figure 1 The LED 29 is arranged so that its center is offset from the straight line connecting the center of the detection surface of the camera 26 and the center of the base of the tip 25. When the arm 24 is in the second position, the LED 29 irradiates light to the area including the opening 14 of the sample heating part 11. The camera 26 is installed in such a direction that, when the arm 24 is in the second position, the area including the opening 14 of the sample heating part 11 illuminated by the LED 29 and the front end of the tip 25 are captured in the field of view.

[0041] Figure 32 shows the area irradiated with light from the LED 29 and the field of view of the camera 26 capturing the area when the arm 24 is in the second position. The light irradiated from the LED 29 illuminates an area 141 outside the opening 14 on the upper surface of the sample heating unit 11, and enters from the opening 14 to illuminate an area 142 that is a part of the inside of the sample heating unit 11. The camera 26 captures the illuminated area 141 outside the opening 14 on the upper surface of the sample heating unit 11 and an area 143 that is a part of the inside of the opening 14 in the field of view. The area 142 inside the sample heating unit 11 illuminated by the LED 29 is different from the area 143 inside the sample heating unit 11 captured by the camera 26. Therefore, in the image captured by the camera 26, the area 141 outside the opening 14 on the upper surface of the sample heating unit 11 is bright, and the area 143 inside the opening 14 is dark.

[0042] The control / processing unit 4 has a storage unit 41. The storage unit 41 stores various measurement conditions used in the measurement using the atomic absorption spectrophotometer 1 (for example, information that establishes a correspondence between the element to be measured and the type of light source used in the measurement of the element and the wavelength of light detected by the detector 13). In addition, the storage unit 41 stores position information of the first position, the second position (including the offset position), and the third position (for example, coordinate information of the second position and the third position in a coordinate system with the first position as the origin), or information on the movement amount of the arm 24 based on the moving mechanism 27 when the arm 24 is moved between the first position, the second position, and the third position. In addition, the storage unit 41 stores various image processing programs used in determining the center position of the opening 14 of the sample heating unit 11, filters used in image processing, parameters used in image processing, etc.

[0043] In addition, the control / processing unit 4 includes: an image acquisition unit 42, an image processing unit 43, a position information acquisition unit 44, an analysis control unit 45, and a measurement data processing unit 46 as functional blocks. The entity of the control / processing unit 4 is a general personal computer, and the above functional blocks are realized by executing a pre-installed atomic absorption spectrophotometer program by a processor. An input unit 51 composed of a keyboard or a mouse and a display unit 52 composed of a liquid crystal display are connected to the control / processing unit 4.

[0044] The analysis control unit 45 reads the measurement conditions stored in the storage unit 41 according to the input operation performed by the analyst, controls the operation of each unit constituting the analysis unit 3, and performs the measurement of the sample. The measurement data processing unit 46 analyzes the measurement data of the sample acquired by the analysis control unit 45 by performing appropriate processing on the measurement data. The analysis control unit 45 and the measurement data processing unit 46 are the same as those included in the conventional atomic absorption spectrophotometer, and therefore, a detailed description thereof is omitted.

[0045] In the case of the atomic absorption spectrophotometer 1, the tip 25 deteriorates during repeated use, resulting in an error in the injection amount of the sample, or the tip 25 becomes clogged, causing the previously measured liquid sample to remain in the tip 25, resulting in contamination. In order to prevent these situations, the analyst needs to replace the tip 25 at an appropriate time. In addition, since the sample heating unit 11 also deteriorates during repeated use, the analyst replaces the sample heating unit 11 at an appropriate time. At this time, since the analyst replaces the tip 25 or the sample heating unit 11 by manual work, installation errors such as the tip 25 being installed on the arm 24 in an inclined state or the installation position of the sample heating unit 11 being misaligned may occur. In the atomic absorption spectrophotometer 1 of this embodiment, the size of the opening 14 of the sample heating unit 11 is 1.8 mm in diameter, the outer diameter of the tip 25 is 1.5 mm, and the error allowed in the radial direction is very small, which is 0.15 mm. If the misalignment between the center position of the tip 25 and the center position of the opening 14 of the sample heating section 11 is greater than this, the tip 25 comes into contact with the sample injection section.

[0046] In the past, when replacing the tip or the sample heating unit, the tip and the opening of the sample heating unit were photographed with a camera to align the tip of the tip with the opening of the sample heating unit. However, the sample heating unit is located deep in the bottom of the light shielding / heat insulating member, and its opening is difficult to confirm.

[0047] Therefore, in the case of the atomic absorption spectrophotometer 1 of this embodiment, after replacing the sample heating part 11 and / or the tip 25, the analyst confirms the center position of the opening 14 of the sample heating part 11 and / or the tip position of the tip 25 in the following procedure. Figure 4 This is a flowchart of the procedure for confirming the position of the center of the opening 14 of the sample heating unit 11 and the tip of the tip 25 in this embodiment.

[0048] When the analyst performs a predetermined input operation to instruct confirmation of the center of the opening 14 of the sample heating unit 11 and the position of the tip 25, the image acquisition unit 42 moves the arm 24 to the third position via the moving mechanism 27 (step 1). The third position is Figure 1When the tip of the tip 25 is photographed at the position indicated by the solid line, an image in which only the tip of the tip 25 is photographed without overlapping with the opening 14 can be obtained.

[0049] Next, the image acquisition unit 42 turns on the LED 29 to illuminate the vicinity of the tip of the tip 25 , and acquires an image of the region including the tip of the tip 25 using the camera 26 (step 2 ), and stores the image in the storage unit 41 .

[0050] After the image acquisition unit 42 acquires an image including the tip of the tip 25, the image processing unit 43 first reads the image data from the storage unit 41, extracts the image of the tip of the tip 25 (the partial image of the tip 25) (step 3), and displays it on the screen of the display unit 52. The process of extracting the partial image of the tip 25 can be performed, for example, by automatically extracting an image within a predetermined range from the center of the image including the tip of the tip 25. The maximum mounting error that may occur when the tip 25 is mounted is about several mm, so it is sufficient to set the size of the pre-extracted image (the predetermined range) so that the tip of the tip 25 is included even when the maximum error occurs. Alternatively, the brightness values ​​of each pixel constituting the entire image may be binarized as light / dark using a threshold value obtained through statistical processing based on the brightness distribution in the image or a predetermined threshold value, and a partial image including the front end of the pointed beak 25 may be extracted based on the attributes corresponding to the shape or area of ​​the front end of the pointed beak 25, such as the area, center of gravity, outer circumference, and circularity of the bright or dark portion (the bright portion when the pointed beak 25 is photographed brightly) block contained in the binarized image.

[0051] In addition, if Figure 5 As shown, a frame indicating the range of the partial image extracted in the above process may be superimposed on the image read from the storage unit 41 and displayed on the screen of the display unit 52, so that the analyst can change the range of the partial image to be extracted as needed. In addition, in the case where the tip of the beak 25 is captured sufficiently large in the image captured by the camera 26 and the remaining area is small, or in the case where there is no area with similar shape features other than the tip of the beak 25, step 3 may be omitted.

[0052] After extracting the partial image of the beak 25, the image processing unit 43 removes noise from the partial image (step 4). For example, a noise removal filter such as a median filter or a moving average filter conventionally used in the field of image processing can be used to remove noise. If the partial image contains almost no noise, step 4 can be omitted.

[0053] The image processing unit 43 further extracts the block with the largest area included in the partial image from which the noise has been removed, and determines the position of its tip end (step 5). Alternatively, the shape and size of the tip end of the tip 25 assumed may be determined in advance based on the shape and area of ​​the tip 25, the magnification when the camera 26 is used to take the image, and the like, and a block satisfying the necessary conditions of the shape and size may be extracted.

[0054] When determining the tip position based on the partial image of the tip 25, for example, first, the contour line (outline) of the largest area block in the partial image is determined ( Figure 6 Then, the center line of the tip 25 is drawn in the middle of the outer contour lines on both sides of the tip 25, and the intersection of the center line and the front end of the outer contour line is obtained, thereby determining the front end position of the tip 25 ( Figure 7 ). Figure 8 2 shows an example of the result of determining the tip position of the tip 25. After the tip position of the tip 25 is determined by the image processing unit 43, the position information acquisition unit 44 stores the information of the position in the storage unit 41.

[0055] After the information on the tip position of the tip 25 is stored in the storage unit 41, the image acquisition unit 42 moves the arm 24 to the second position (offset position) via the moving mechanism 27 (step 6). The second position is originally Figure 1 The position indicated by the dotted line in the figure is the sample injection position where the tip 25 is located directly above the opening 14. However, if the opening 14 is photographed at the sample collection position, the tip 25 and the opening 14 overlap in the acquired image. Therefore, the arm 24 is moved to a position where it is displaced in a predetermined direction by a predetermined length, that is, an offset position. The direction and length can be appropriately determined by taking into account the size or shape of the tip 25 and performing a preliminary photograph so that the photographed position of the tip 25 and the opening 14 do not overlap.

[0056] Next, the image acquisition unit 42 turns on the LED 29 to illuminate the vicinity of the opening 14 , and acquires an image of a region including the opening 14 using the camera 26 (step 7 ), and stores the image in the storage unit 41 .

[0057] After the image acquisition unit 42 acquires an image including the opening 14, the image processing unit 43 first reads the image data from the storage unit 41, extracts an image of the vicinity of the opening 14 (a partial image of the opening) (step 8), and displays it on the screen of the display unit 52. The process of extracting the partial image of the opening 14 can be performed, for example, by automatically extracting an image within a predetermined range from the center of the image acquired by the image acquisition unit 42. The installation error of the position of the opening 14 that may occur when the sample heating unit 11 is installed is also about several mm at most. Therefore, it is sufficient to set the size of the pre-extracted image (the predetermined range) in such a way that the opening 14 is included even when the maximum error occurs.

[0058] In addition, a frame indicating the range of the partial image extracted in the above process may be superimposed on the image read from the storage unit 41 and displayed on the screen of the display unit 52, so that the analyst can change the range of the partial image to be extracted as needed. In addition, in the case where the opening 14 is captured sufficiently large in the image captured by the camera 26 and the remaining area is small, or in the case where there is no area with similar shape features other than the opening 14, step 8 may be omitted.

[0059] After extracting the partial image of the opening 14, the image processing unit 43 removes noise from the partial image (step 9). Noise removal may be performed in the same manner as the noise removal of the partial image of the tip 25. In addition, step 9 may be omitted when the partial image contains almost no noise.

[0060] Next, the image processing unit 43 extracts the edge contained in the partial image of the opening 14 from which the noise has been removed (step 10). The edge extraction can be performed by using, for example, an edge processing filter such as a Sobel filter, a Laplacian filter, or a Canny filter that has been conventionally used in the field of image processing. Fig. 9 An example of a partial image from which edges are extracted is shown in FIG. In the example, edges contained in the partial image from which noise is removed are extracted, but instead of extracting edges, a process of binarizing the brightness value of each pixel into light / dark values ​​may be performed using a predetermined brightness value threshold or a threshold value calculated based on brightness distribution in the image.

[0061] Next, the image processing unit 43 extracts the circular area corresponding to the opening 14 from the partial image after edge extraction, and determines its center position (step 11). The circular area can be extracted by, for example, Hough transformation. Fig.10As shown, in the partial image after edge extraction, circles of radius r are drawn with the positions of the pixels (edge ​​points) constituting the edge as the center, and the intersection point where the most circles overlap is determined as the center position of the opening 14 . Fig.11 2 shows an example of an image in which a circular area corresponding to the opening 14 is extracted. The radius r may be predetermined based on the actual radius of the opening 14 and the magnification when the image is acquired by the camera 26. In the above method, the center position of the opening 14 can be determined with a spatial resolution of the pixel level.

[0062] The processing using the Hough transform in the present embodiment is a method of determining the center position of the opening 14 by so-called majority voting. Therefore, even if a part of the edge of the opening 14 is missing in the partial image of the opening 14 after edge extraction, the circle corresponding to the opening 14 can be detected. In the case of the atomic absorption spectrophotometer 1, the heating furnace constituting the sample heating portion 11 deteriorates during repeated use. As a result, the contrast between the inside and the peripheral portion of the opening 14 is reduced in the partial image of the opening 14, and a part of the edge corresponding to the opening 14 may not be extracted. By using the Hough transform as in the present embodiment, the center position of the opening 14 can be determined even if a part of the edge corresponding to the opening 14 is not extracted.

[0063] When the center position of the opening 14 is determined at a higher resolution, the intersection of the most overlapping circles is determined by Hough transformation as in step 11, and then a circle containing edge points (pixels) of the circle passing through the intersection is determined (in other words, a circumscribed circle of all edge points of the circle passing through the intersection), and the center of the circumscribed circle is determined as the center position of the opening 14. In the method, the center position of the opening 14 can be determined at a spatial resolution of pixel level or higher. After the center position of the opening 14 is determined by the image processing unit 43, the position information acquisition unit 44 stores the information of the position in the storage unit 41.

[0064] In addition, when only the portion corresponding to the opening 14 can be extracted in step 8, Hough transform can be omitted, and the circumscribed circle of each pixel (edge ​​point) constituting the edge can be directly calculated based on the partial image after edge extraction, and the center of the circumscribed circle can be determined as the center position of the opening 14. Fig.12 An example of the result of determining the center position 144 of the opening 14 is shown in FIG.

[0065] After determining the tip position of the tip 25 and the center position 144 of the opening 14, the position information acquisition unit 44 calculates the distance between the two based on the position information stored in the storage unit 41 (step 12), and stores it in the storage unit 41. Then, when measuring the sample thereafter, the moving mechanism 27 moves the arm 24 between the first position, the second position, and the third position based on the distance information calculated by the position information acquisition unit 44. Thus, it is possible to eliminate the installation error that occurs when the analyst replaces the sample heating unit 11 or the tip 25.

[0066] The above-described embodiment is merely an example and can be modified as appropriate based on the spirit of the present invention.

[0067] In the above embodiment, the camera 26 and the LED 29 are mounted on the arm 24, and the camera 26 and the LED 29 move together with the arm 24. However, one or both of the camera 26 and the LED 29 may be fixed without being mounted on the arm 24. In such a case, the camera 26 or the LED 29 may be arranged at the third position and the offset position, respectively.

[0068] In the embodiment, the tip of the tip 25 is photographed at the third position, but the area including the opening 14 and the tip of the tip 25 may be photographed at the same position (offset position of the second position). However, by photographing at the third position as in the embodiment, objects other than the tip 25 are excluded from being photographed, thereby expecting to improve the detection accuracy of the tip position of the tip 25. In many cases, the tip 25 uses a resin tip, and when light is irradiated from the LED 29, the position of the tip 25 becomes bright. Therefore, for the third position, a place where the background is dark and the contrast with the tip 25 is large can be selected. Alternatively, a light source that emits light of a wavelength that does not penetrate the material (resin, etc.) constituting the tip 25 can be used, and a position with a bright background can be set as the third position, and the tip 25 can be photographed at the third position, thereby obtaining an image in which the tip 25 is dark and the background is bright.

[0069] In the embodiment, the center position of the opening 14 and the front end position of the pointed mouth 25 are determined by image processing, but image processing is not necessary for the present invention. An image of the front end of the opening 14 and / or the pointed mouth 25 may be displayed on the screen of the display unit 52, and an analyst may confirm the image to determine the center position of the opening 14 or the front end position of the pointed mouth 25.

[0070] In addition, when there are a plurality of bright (or dark) blocks smaller than the opening 14 in the image after binarizing the brightness value of the partial image of the opening 14, the blocks smaller than the opening 14 may be removed from the image by combining morphological processing and the like, and noise may be removed, thereby obtaining a partial image highlighting the opening 14. Furthermore, a pattern of an image corresponding to the shape of the opening 14 may be stored in the storage unit 41 in advance, and the position of the opening 14 may be determined by pattern matching to extract the partial image.

[0071] A method different from the above-described embodiment may be used to determine the center position of the opening 14. For example, the contour line (outline) of the opening 14 may be obtained by Hough transformation as in the above-described embodiment, and the center of gravity of the plurality of pixels where the outline is located may be determined as the center position of the opening 14. Alternatively, the equation of the circle that is most similar to the outline may be obtained by the least square method or the like, and the center position of the opening 14 may be determined based on the equation.

[0072] In addition, when the pointed beak 25 is photographed at the third position, a reference image that only captures the background of the third position can be saved in the storage unit 41, and the difference between the image obtained by photographing the front end of the pointed beak 25 by the camera 26 and the reference image can be obtained, thereby extracting a partial image of the pointed beak 25.

[0073] Furthermore, when the tip 25 is photographed at the third position as in the above-described embodiment and an image in which the boundary between the tip 25 and its background is clearly visible is obtained, the tip position of the tip 25 may be determined by extracting only the pixel located at the front end (or the midpoint of the pixels when a plurality of pixels are arranged at the front end) without performing processing such as extracting the outline. Alternatively, the minimum circumscribed rectangle of the block constituting the tip 25 in the partial image may be obtained, and the midpoint of the short side located at the front end side thereof may be determined as the tip position of the tip 25. Alternatively, as Fig.13 As shown, the intersection of a line located in the middle of the two major axes of the minimum circumscribed rectangle (the center line crossing the minor axis of the rectangle) and the boundary portion on the front end side may be determined as the front end position of the tip 25. Furthermore, when the tip 25 is photographed at the third position, another camera may be arranged just below the tip 25 to photograph the tip 25, and the shape (circle, rectangle, etc.) corresponding to the cross section of the tip 25 may be extracted from the image, and the center thereof may be determined as the front end position of the tip 25. In addition, when extracting a circular portion or the like from the image, various methods that can be used when determining the opening 14 may be used.

[0074] In the above embodiment, when the arm 24 is in the second position, the components are arranged so that the LED 29 is located on the opposite side of the camera 26 across the opening 14 in a plan view, but the LED 29 and the camera 26 may be arranged on the same side with respect to the opening 14. However, in this case, the LED 29 and the camera 26 are arranged so that the optical axes are different from each other.

[0075] [form]

[0076] Those skilled in the art will appreciate that the multiple exemplary embodiments described above are specific examples of the following forms.

[0077] (First Item)

[0078] An atomic absorption spectrophotometer according to one aspect of the present invention comprises:

[0079] The sample collection part is equipped with a sharp nozzle for collecting and ejecting the sample;

[0080] A sample heating part, the upper surface of which is provided with an opening for injecting the sample;

[0081] a moving mechanism for moving the sample collecting portion between a first position for collecting the sample into the tip and a second position for injecting the sample from the tip into the opening;

[0082] a light irradiation unit that irradiates light toward the opening from a predetermined direction; and

[0083] The image acquisition unit captures an image of the opening from an optical axis direction different from a central axis of the light irradiated by the light irradiation unit.

[0084] In the case of the atomic absorption spectrophotometer of the first item, the light irradiation unit irradiates light from a predetermined direction to the opening provided on the upper surface of the sample heating unit, and the image acquisition unit photographs the opening from an optical axis direction different from the optical axis of the light irradiation unit. In the atomic absorption spectrophotometer of the first item, since an image having a light-dark contrast around the opening of the sample heating unit is acquired using the light irradiation unit and the image acquisition unit having mutually different optical axes, the position of the opening can be easily confirmed.

[0085] (Second Item)

[0086] The atomic absorption spectrophotometer according to the first item, wherein

[0087] The image acquisition unit is configured to capture a region inside the opening that is not irradiated with light from the light irradiation unit in a field of view.

[0088] (Third Item)

[0089] The atomic absorption spectrophotometer according to the first or second item, wherein:

[0090] The light irradiation section, the image acquisition section, and the sample heating section are arranged so that the light irradiation section is located on the opposite side to the image acquisition section across the opening in a plan view.

[0091] (4th item)

[0092] The atomic absorption spectrophotometer according to the first or second item, wherein:

[0093] The light irradiation section, the image acquisition section, and the sample heating section are arranged so that the light irradiation section and the image acquisition section are located on the same side with respect to the opening in a plan view.

[0094] In the case of the atomic absorption spectrophotometers of the second to fourth items, the position of the opening can be confirmed more accurately by taking an image with a high contrast in which the upper surface of the sample heating portion is bright and the opening is dark. In the case of the atomic absorption spectrophotometers of the second to fourth items, even when the opening is photographed with the tip attached to the sample collection portion, the two can be easily distinguished by photographing the inside of the opening darkly and the tip brightly.

[0095] (Fifth Item)

[0096] The atomic absorption spectrophotometer according to any one of items 1 to 4, wherein

[0097] The moving mechanism further moves the sample collecting portion to a third position different from the first position and the second position.

[0098] When the sample collecting portion is located at the third position, the image acquiring portion captures a front end of the tip.

[0099] In atomic absorption spectrophotometers, resin tips are used in most cases. When photographing a resin tip, the position of the tip becomes bright. In the case of the atomic absorption spectrophotometer of the fifth item, the tip can be photographed independently of the sample container located at the first position or the sample heating unit located at the second position. In addition, regarding the third position, it is preferable to select a location with a background having a large contrast with the tip. For example, by setting a third position with a dark background and photographing the tip of the tip brightly at the third position, an image having a large contrast between the tip and the background can be photographed. In the case where the tip is photographed darkly by irradiating light of a wavelength that does not penetrate the tip, etc., a third position with a bright background can also be set. Furthermore, the outline of the tip can also be photographed by irradiating light from the back side of the tip (transmitted illumination).

[0100] (Sixth Item)

[0101] The atomic absorption spectrophotometer according to any one of items 1 to 5, wherein

[0102] The light irradiation unit and the image acquisition unit are installed in the sample collection unit.

[0103] In the case of the atomic absorption spectrophotometer of the sixth item, since the relative positions of the light irradiation section and the image acquisition section are fixed, the opening can be imaged in the same state at all times.

[0104] (Item 7)

[0105] The atomic absorption spectrophotometer according to item 6, wherein:

[0106] The moving mechanism further moves the sample collecting portion to a position offset from the second position in the horizontal direction and / or the vertical direction.

[0107] The image acquisition unit captures an image of the opening when located at the offset position.

[0108] In the case of the atomic absorption spectrophotometer of the seventh item, by appropriately determining the offset amount, it is possible to acquire an image in which the positions of the opening of the sample heating portion and the tip of the nozzle are shifted.

[0109] (Item 8)

[0110] The atomic absorption spectrophotometer according to any one of the first to seventh items, further comprising:

[0111] The image processing unit determines the center position of the opening by performing image processing on the image of the opening captured by the image acquisition unit.

[0112] (Item 9)

[0113] The atomic absorption spectrophotometer according to item 8, wherein:

[0114] The opening is circular,

[0115] The image processing unit extracts the contour line of the opening by extracting the edges contained in the image of the opening or binarizing the brightness values ​​of each pixel of the image of the opening, and obtains the area corresponding to the opening by performing a Hough transform based on the positions of the pixels corresponding to the contour line and the values ​​of the radius of a predetermined range, and determines the center of the area, thereby determining the center position of the opening.

[0116] (Item 10)

[0117] The atomic absorption spectrophotometer according to item 8 or 9, wherein:

[0118] The image processing unit extracts the area of ​​the opening by extracting the edges contained in the image of the opening or binarizing the brightness values ​​of each pixel of the image of the opening, and finds a circumscribed circle including the pixels corresponding to the area, and determines the center of the circumscribed circle as the center position of the opening.

[0119] In the case of the atomic absorption spectrophotometers of the eighth to tenth items, since the center position of the opening is determined by the image processing unit, the analyst can easily determine the center position of the opening without personally confirming the image. In addition, as image processing for determining the center position of the opening, for example, the following method can be used: extracting the contour line of the opening and extracting the area of ​​the opening by Hough transformation based on the position of the pixel corresponding to the contour line and the value of the radius of a predetermined range as in the atomic absorption spectrophotometer of the ninth item; or extracting the area of ​​the opening and determining the circumscribed circle containing the pixels corresponding to the area as in the atomic absorption spectrophotometer of the tenth item to determine the center position of the opening. Furthermore, the methods of the atomic absorption spectrophotometers of the ninth and tenth items can also be combined to extract the area of ​​the opening by Hough transformation, determine its circumscribed circle, and determine the center of the circumscribed circle, thereby determining the center position of the opening. In the case of the atomic absorption spectrophotometer of the ninth item, the center position of the opening can be determined at a resolution of pixel units, and in the case of the atomic absorption spectrophotometer of the tenth item, the center position of the opening can be determined at a resolution of more than pixel units.

[0120] (Item 11)

[0121] The atomic absorption spectrophotometer according to any one of items 8 to 10, wherein

[0122] The image processing unit further extracts the contour of the pointed beak and identifies its front end by extracting edges contained in the image of the pointed beak captured by the image acquisition unit, binarizing the brightness values ​​of each pixel of the image of the pointed beak, or calculating the difference between a pre-prepared background image that does not include the pointed beak and the image of the pointed beak, thereby determining the position of the front end of the pointed beak.

[0123] (Item 12)

[0124] The atomic absorption spectrophotometer according to item 11, wherein

[0125] The image processing unit determines the tip position of the pointed mouth by defining the center line of the pointed mouth in the middle of the outer shape line of the pointed mouth located on both sides of the tip in the contour line and finding the intersection of the center line and the tip, or by finding a rectangle circumscribed with the contour line and determining the intersection of the short side of the rectangle located on the tip side of the pointed mouth and the center line of the two long sides of the rectangle.

[0126] In the case of the atomic absorption spectrophotometers of the eleventh and twelfth items, in addition to determining the center position of the opening, the tip position of the tip can also be determined.

[0127] (Item 13)

[0128] The atomic absorption spectrophotometer according to any one of the eighth to twelfth items, further comprising:

[0129] The position information acquisition unit calculates the distance between the tip of the tip and the center of the opening based on the processing result obtained by the image processing unit.

[0130] In the case of the atomic absorption spectrophotometer of item 13, the distance between the front end of the tip and the center of the opening can be calculated by the position information acquisition unit based on the processing result obtained by the image processing unit after eliminating the positional misalignment caused by replacement of the sample heating unit or the tip.

[0131] Explanation of symbols

[0132] 1: Atomic absorption spectrophotometer

[0133] 10: Measurement unit

[0134] 11: Sample heating unit

[0135] 12: Light source

[0136] 13: Detector

[0137] 14: Opening

[0138] 15: Shading / heat insulation components

[0139] 20: Autosampler

[0140] 21: Turntable

[0141] 22: Sample container

[0142] 23: Shaft component

[0143] 24: Arm

[0144] 25: Pointed Mouth

[0145] 26: Camera

[0146] 27: Mobile mechanism

[0147] 29: LED

[0148] 3: Analysis Department

[0149] 4: Control / Processing Unit

[0150] 41: Storage

[0151] 42: Image acquisition unit

[0152] 43: Image processing department

[0153] 44: Location information acquisition unit

[0154] 45: Analysis and Control Department

[0155] 46: Measurement data processing unit

[0156] 51: Input

[0157] 52: Display unit

Claims

1. An atomic absorption spectrophotometer, characterized in that: include: The sample collection part is equipped with a sharp nozzle for collecting and ejecting the sample; A sample heating part, the upper surface of which is provided with an opening for injecting the sample; a moving mechanism for moving the sample collecting portion between a first position for collecting the sample into the tip and a second position for injecting the sample from the tip into the opening; a light irradiation unit for irradiating light to the opening from a predetermined direction; as well as The image acquisition unit captures an image of the opening from an optical axis direction different from a central axis of the light irradiated by the light irradiation unit.

2. The atomic absorption spectrophotometer according to claim 1, characterized in that: The image acquisition unit is configured to capture a region inside the opening that is not irradiated with light from the light irradiation unit in a field of view.

3. The atomic absorption spectrophotometer according to claim 1, characterized in that: The light irradiation section, the image acquisition section, and the sample heating section are arranged so that the light irradiation section is located on the opposite side to the image acquisition section across the opening in a plan view.

4. The atomic absorption spectrophotometer according to claim 1, characterized in that: The light irradiation section, the image acquisition section, and the sample heating section are arranged so that the light irradiation section and the image acquisition section are located on the same side with respect to the opening in a plan view.

5. The atomic absorption spectrophotometer according to claim 1, characterized in that: The moving mechanism further moves the sample collecting portion to a third position different from the first position and the second position. When the sample collecting portion is located at the third position, the image acquiring portion captures a front end of the tip.

6. The atomic absorption spectrophotometer according to claim 1, characterized in that: The light irradiation unit and the image acquisition unit are installed in the sample collection unit.

7. The atomic absorption spectrophotometer according to claim 6, characterized in that: The moving mechanism further moves the sample collecting portion to a position offset from the second position in the horizontal direction and / or the vertical direction. The image acquisition unit captures an image of the opening when located at the offset position.

8. The atomic absorption spectrophotometer according to claim 1, characterized in that: Also includes: The image processing unit determines the center position of the opening by performing image processing on the image of the opening captured by the image acquisition unit.

9. The atomic absorption spectrophotometer according to claim 8, characterized in that: The opening is circular, The image processing unit extracts the contour line of the opening by extracting the edges contained in the image of the opening or binarizing the brightness values ​​of each pixel of the image of the opening, and obtains the area corresponding to the opening by performing a Hough transform based on the positions of the pixels corresponding to the contour line and the values ​​of the radius of a predetermined range, and determines the center of the area, thereby determining the center position of the opening.

10. The atomic absorption spectrophotometer according to claim 8, characterized in that: The image processing unit extracts the area of ​​the opening by extracting the edges contained in the image of the opening or binarizing the brightness values ​​of each pixel of the image of the opening, and finds a circumscribed circle including the pixels corresponding to the area, and determines the center of the circumscribed circle as the center position of the opening.

11. The atomic absorption spectrophotometer according to claim 8, characterized in that: The image processing unit further extracts the contour of the pointed beak and identifies its front end by extracting edges contained in the image of the pointed beak captured by the image acquisition unit, binarizing the brightness values ​​of each pixel of the image of the pointed beak, or calculating the difference between a pre-prepared background image that does not include the pointed beak and the image of the pointed beak, thereby determining the position of the front end of the pointed beak.

12. The atomic absorption spectrophotometer according to claim 11, characterized in that: The image processing unit determines the tip position of the pointed mouth by defining the center line of the pointed mouth in the middle of the outer shape line of the pointed mouth located on both sides of the tip in the contour line and finding the intersection of the center line and the tip, or by finding a rectangle circumscribed with the contour line and determining the intersection of the short side of the rectangle located on the tip side of the pointed mouth and the center line of the two long sides of the rectangle.

13. The atomic absorption spectrophotometer according to claim 8, characterized in that: Also includes: The position information acquisition unit calculates the distance between the tip of the nozzle and the center of the opening based on the processing result obtained by the image processing unit.

Images