Biological sample measurement device and calibration method

Abstract

The purpose of the present disclosure is to avoid a decrease in liquid level measurement accuracy due to deviation of a measurement device and lens aberration when measuring a biological sample having one or more component regions. A biological sample measurement device according to the present disclosure acquires a distortion coefficient and a liquid level conversion coefficient from an image captured by a calibrator having a pattern shape on the surface, and corrects the liquid level of a sample on the basis of these coefficients (referring to Figure 1).

Description

Technical Field

[0001] The present disclosure relates to an apparatus for measuring a biological sample separated into a plurality of component regions. Background Art

[0002] In order to improve the efficiency of clinical examinations such as blood tests, technology is required to automate the liquid volume confirmation of biological specimens before analysis (before dispensing), which was previously performed by visual confirmation. The specimen to be analyzed is separated into multiple layers by centrifugation, etc., and technology is required to measure only the liquid volume of the sample to be analyzed, such as serum and plasma. In addition, when the specimen is a blood sample, a barcode label for patient identification is affixed to the blood collection tube containing the specimen, and technology is required to be able to perform measurements in the state of being affixed with the label. Furthermore, it is desired to install a specimen measurement device as an option in the specimen transport device that has already been introduced, and miniaturization of the device is required.

[0003] As such a biological sample measuring device, for example, Patent Document 1 discloses the following technology: a sample separated into multiple layers is irradiated with pulsed light of two wavelengths by switching between them in time division, and the transmitted light is measured while scanning the sample in the vertical direction, thereby detecting the height of a predetermined area of ​​the sample separated into multiple layers.

[0004] Patent document 2 discloses a technology for generating a captured image of a biological sample using a light source with two wavelength components emitted by a light source and an area camera, comparing the captured images generated using exposure times or gains when shooting with two or more images, and thereby selecting the captured image of the biological sample that can most clearly identify the portion of the measurement object.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: US2012 / 0013889

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-178784 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The technology disclosed in Patent Document 1 relates to a liquid volume measurement technique for a biological sample composed of multiple components. This technique uses signals from two wavelengths of transmitted light with different absorbances relative to the sample to accurately determine the boundaries of the measurement target region. However, Patent Document 1 requires vertical scanning of the sample (blood collection tube) along its longitudinal axis while performing the measurement, making it difficult to miniaturize the device due to the scanning mechanism.

[0011] The technology disclosed in Patent Document 2 relates to a liquid volume measurement technique that uses an area camera to obtain a transmission image of near-infrared light. This technique eliminates the need for sample rotation or vertical scanning mechanisms, even in labeled biological samples, enabling device miniaturization. This technique detects the area to be measured from the transmission image, determines the liquid level, and calculates the liquid volume. However, this requires a conversion coefficient to convert the number of pixels in the measurement area into a length. This conversion coefficient is determined based on the distance from the biological sample to the area camera, so avoiding the effects of device misalignment caused by installation, etc., is a challenge. Furthermore, images captured by the area camera are distorted due to lens aberrations, so accurate liquid level detection requires image distortion correction.

[0012] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to avoid a decrease in the liquid level measurement accuracy caused by deviation of the measuring device and lens aberration when measuring a biological sample having one or more component regions.

[0013] Means for solving problems

[0014] The biological sample measurement device according to the present disclosure acquires a distortion coefficient and a liquid level conversion coefficient from a captured image of an etalon having a patterned surface, and corrects the liquid level of a sample based on these coefficients.

[0015] Effects of the Invention

[0016] According to the biological sample measurement device disclosed herein, when measuring a biological sample having one or more component regions, a decrease in liquid level measurement accuracy caused by device deviation and lens aberration can be avoided, thereby improving analysis accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a configuration diagram of the biological sample measurement device 101 according to the first embodiment.

[0018] Figure 2A This is a diagram explaining the principle of determining the measurement target area.

[0019] Figure 2B This is a diagram explaining the principle of determining the measurement target area.

[0020] Figure 3A is an example of calibrator 301.

[0021] Figure 3B is an example of calibrator 301.

[0022] Figure 4A 302 is a diagram showing an example of the pattern 302 .

[0023] Figure 4B302 is a diagram showing an example of the pattern 302 .

[0024] Figure 5 This is a diagram for explaining an imaging method of the calibrator 301 .

[0025] Figure 6A is used Figure 5 FIG. 6 is an explanatory diagram of an aligner image 601 obtained by photographing an aligner 301 having a structure in which light and dark stripes are spaced at constant intervals.

[0026] Figure 6B It means in Figure 6A Graph showing the distribution of the number of pixels [pixel] between fringe lines when lens distortion exists in the analysis range 602.

[0027] Figure 7 It means Figure 6B Graph showing the liquid level conversion coefficient [mm / pixel] obtained by dividing the actual fringe interval length [mm] by the fringe period [pixel].

[0028] Figure 8 This is a flowchart of the process of obtaining the distortion coefficient by the distortion coefficient calculation unit 109.

[0029] Figure 9 This is a flowchart illustrating a method for obtaining a liquid level conversion coefficient after performing distortion correction on the calibrator image 601 .

[0030] Figure 10 It is based on Figure 8 A flowchart of a method for obtaining a liquid level height conversion coefficient as a distribution (function) with vertical coordinates as variables using the distortion coefficient and distortion function obtained in the process.

[0031] Figure 11 It is used in Figure 9 Flowchart of a method for measuring liquid volume using a constant liquid level conversion coefficient obtained in .

[0032] Figure 12 It is used in Figure 10 Flowchart of a method for measuring liquid volume using the distribution of liquid level height conversion coefficients obtained during processing.

[0033] Figure 13 This is a configuration diagram of a biological sample measurement device 101 according to the second embodiment.

[0034] Figure 14 This is a flowchart illustrating a method of adjusting the imaging position of the biological sample 102 according to the value of the liquid level conversion coefficient. DETAILED DESCRIPTION

[0035] <Implementation Method 1>

[0036] The biological sample measured in the embodiments of the present disclosure is a specimen with a label attached before unsealing (before analysis), and is assumed to be separated into multiple component layers (typically one to three layers) by centrifugation. The measurement target is the portion of the specimen separated into multiple layers, such as plasma or serum, that is the target of analysis (the target of aliquoting) by a biochemical analyzer, etc.

[0037] Figure 1 This is a structural diagram of a biological sample measurement device 101 according to Embodiment 1 of the present disclosure. The biological sample measurement device 101 measures a biological sample 102. As described above, the biological sample 102 is composed of multiple layers. The biological sample measurement device 101 identifies a measurement target region 103 of the biological sample 102 and measures the liquid volume therein. The biological sample measurement device 101 includes a surface illumination light source 104, an area camera 105, a time-sharing control driver 106, a calibration data acquisition unit 107, and a liquid volume measurement unit 108.

[0038] The surface illumination light source 104 is configured to switch the wavelength of the emitted light between two wavelengths, and uses this light to illuminate the biological sample 102. The light emitted by the surface illumination light source 104 can illuminate two or more component layers constituting the biological sample 102 at the same time (i.e., across two or more component layers). In addition, regardless of the component layers, the upper surface of the uppermost layer (the boundary between the sample and the air layer) can be irradiated. The wavelength of the switching light does not necessarily need to emit light having only a single wavelength, as long as the wavelength component with the strongest intensity can be switched (wavelength λ1 = 970 ± 100 nm, wavelength λ2 = 1550 ± 100 nm, etc.). In the case of a biological sample 102 with one or three component layers, if the number of component layers is known before measurement, any one of the two wavelengths can be used, and there is no need to switch the wavelength. The reason and wavelength selection method will be explained in the measurement principle described later.

[0039] The area camera 105 captures the surface illumination light transmitted through the biological sample 102, generating a two-dimensional image of the biological sample 102. The area camera 105 has sensitivity characteristics capable of detecting light in the wavelength range emitted by the surface illumination light source 104. The area camera 105 can be constructed, for example, from an InGaAs camera. Furthermore, the area camera 105 acquires an image of a calibrator. Details of the calibrator will be described later.

[0040] The time-sharing control driver 106 switches the wavelength of light emitted by the surface illumination light source 104 in a time-sharing manner. In sync with the wavelength switching, the time-sharing control driver 106 adjusts the exposure time (or gain) of the area camera 105 to a time appropriate for the wavelength. The time-sharing control driver 106 controls the imaging timing of the area camera 105 in sync with the wavelength emitted by the surface illumination light source 104. The time-sharing control driver 106 receives processing results from the liquid volume measurement unit 108 and controls re-imaging based on the processing results.

[0041] The calibration data acquisition unit 107 analyzes the calibrator image acquired by the area camera 105. The calibration data acquisition unit 107 includes a distortion coefficient calculation unit 109, a liquid level conversion coefficient calculation unit 110, and a calibration data storage unit 111. The distortion coefficient calculation unit 109 calculates distortion coefficients that represent image distortion due to the influence of lens aberrations. The liquid level conversion coefficient calculation unit 110 calculates conversion coefficients that convert the number of pixels in the liquid level region in the image of the biological sample 102 acquired by the area camera 105 into liquid level height (mm). The calculation methods of the distortion coefficients and liquid level conversion coefficients will be described later. The calibration data storage unit 111 stores the distortion coefficients acquired by the distortion coefficient calculation unit 109 and the liquid level conversion coefficients acquired by the liquid level conversion coefficient calculation unit 110.

[0042] The liquid volume measurement unit 108 extracts the measurement target area 103 from the captured image obtained by the area camera 105 and obtains the vertical liquid level pixel count (pixel) corresponding to the liquid level in the captured image. The liquid volume measurement unit 108 accesses the calibration data storage unit 111, obtains the stored distortion coefficient and liquid level conversion coefficient, and uses these to convert the liquid level pixel count (pixel) obtained from the captured image into the liquid level (mm). Furthermore, the liquid volume is calculated using information on the container diameter of the biological sample 102. Details of the processing performed by the liquid volume measurement unit 108 will be described later.

[0043] <Implementation 1: Principle of Liquid Volume Measurement>

[0044] Figure 2A and Figure 2B This is a diagram explaining the principle of determining the measurement target area. Figure 1 In the structure of Figure 2A and Figure 2B A two-dimensional transmission image of the biological sample 102 is shown.

[0045] Figure 2A An example is shown in which the biological sample 102 is separated into three layers. Figure 2B1 shows an example of a biological sample 102 separated into two layers. The blood clot 202 becomes the lower layer when the biological sample 102 is centrifuged. The separation material 201 is a material mixed in order to separate the blood clot 202 from the measurement target region 103.

[0046] Comparing the first wavelength (wavelength 1) and the second wavelength (wavelength 2) emitted by the surface illumination light source 104, the transmittance of wavelength 1 through the blood clot 202 is substantially the same as the transmittance of wavelength 2 through the blood clot 202. Therefore, the difference between the image of the blood clot 202 captured using wavelength 1 and the image of the blood clot 202 captured using wavelength 2 is extremely small. The same is true for the separation material 201; the transmittance of wavelength 1 and the transmittance of wavelength 2 are substantially the same, so the difference between the two images is extremely small.

[0047] In contrast, the transmittance when wavelength 1 passes through the measurement target region 103 differs significantly from the transmittance when wavelength 2 passes through the measurement target region 103. Therefore, there is a significant difference between the image of the measurement target region 103 captured using wavelength 1 and the image of the measurement target region 103 captured using wavelength 2. By identifying this difference, the measurement target region 103 can be extracted from the captured image.

[0048] like Figure 2A and Figure 2B As illustrated, the wavelengths used as wavelengths 1 and 2 must be preselected so that a significant difference between the wavelengths occurs within measurement target region 103, but little difference occurs elsewhere. The specific wavelength values ​​can be arbitrary as long as this condition is met. Specifically, the difference between the transmittance of wavelength 1 when passing through measurement target region 103 and the transmittance of wavelength 2 when passing through measurement target region 103 must be greater than the difference between the transmittance of wavelength 1 when passing through regions other than measurement target region 103 and the transmittance of wavelength 2 when passing through regions other than measurement target region 103.

[0049] By utilizing the above-described measurement principle, even when biological sample 102 is separated into multiple component layers, measurement target region 103 can be determined. Liquid volume measurement unit 108 determines measurement target region 103 based on this principle. While there is no limit to the number of component layers, typical biological samples such as plasma and serum are separated into one to three layers. In either case, measurement target region 103 can be determined with high accuracy.

[0050] For a biological sample 102 having a single component layer or a biological sample 102 having three component layers, if the number of component layers is known before measurement, measurement can be performed using a transmission image of only one wavelength. Figure 2AIn the case of three layers, a wavelength may be selected at which there is a difference in absorptivity between the separation material 201 or the air layer above and below the measurement target region 103 and the measurement target region 103. In the case of a single layer, a wavelength may be selected at which there is a difference in absorptivity between the air layer above the measurement target region 103 and the measurement target region 103.

[0051] The liquid amount measuring unit 108 detects the boundary of the measurement target area 103 obtained as described above, obtains the number of liquid level pixels corresponding to the liquid level, and uses the obtained number of liquid level pixels and the Figure 1 The liquid level conversion coefficient [mm / Pixel] stored in the calibration data storage unit 111 is used to calculate the liquid level [mm]. The method for calculating the liquid level conversion coefficient will be described later. The liquid volume measurement unit 108 calculates the liquid volume based on the thus calculated liquid level [mm] and the blood collection tube diameter information.

[0052] <Implementation 1: Purpose of Calibration>

[0053] As described above, in order for the biological sample measuring device 101 to calculate the liquid volume, a liquid level conversion coefficient (mm / Pixel) is required to convert the number of liquid level pixels obtained from the captured image into the liquid level (mm). The liquid level conversion coefficient can be calculated based on the field of view (mm) captured by the area camera 105 and the number of sensor pixels of the area camera 105. However, in order to accurately calculate the liquid level (mm), the liquid level conversion coefficient must be accurately calculated, which presents the following two problems.

[0054] The first issue is the deviation in the distance (working distance) between the imaging position of the biological sample 102 and the area camera 105. The field of view of the area camera 105 is enlarged or reduced according to the working distance, and the liquid level conversion coefficient is also determined based on the working distance. If the imaging position of the biological sample 102 or the position of the area camera 105 deviates from each device due to, for example, device installation, the working distance changes, and the value of the liquid level conversion coefficient also deviates, directly leading to a decrease in the accuracy of liquid level measurement (mm). Therefore, to more accurately determine the liquid level conversion coefficient, it is necessary to calibrate the liquid level conversion coefficient for each biological sample measurement device 101.

[0055] The second point concerns image distortion caused by lens aberration. When capturing images using a standard lens that is not a telecentric optical system, lens distortion aberration causes image distortion from the center to the edges of the image. When this image distortion occurs, the liquid level conversion coefficient varies depending on the pixel position, as described in detail later. Therefore, to accurately determine the liquid level conversion coefficient, it is necessary to detect image distortion and calibrate the liquid level conversion coefficient accordingly. In particular, since the biological sample measuring device 101 measures the liquid level in the measurement target area 103, it is necessary to correct distortion in the liquid level direction.

[0056] To address the two issues outlined above, calibration, described below, is performed on each biological sample measurement device 101. During calibration, distortion coefficients representing image distortion and liquid level conversion coefficients used to calculate and correct the liquid level based on the distortion coefficients are acquired for each device, with the goal of obtaining a highly accurate liquid level conversion coefficient. These coefficients are then stored in the calibration data storage unit 111. The liquid volume measurement unit 108 acquires the distortion coefficients and liquid level conversion coefficients stored in the calibration data storage unit 111 and uses them to calculate the liquid level, thereby enabling highly accurate calculation of the liquid level in mm.

[0057] <Implementation 1: Calibration Step>

[0058] Figure 3A and Figure 3B This is an example of the calibrator 301. The calibration data acquisition unit 107 acquires the image of the calibrator 301 captured by the area camera 105, analyzes the shape pattern formed on the surface of the calibrator 301, and acquires the distortion coefficient and the liquid level conversion coefficient.

[0059] Calibrator 301 is Figure 3A Such a flat or Figure 3B The calibrator has a cylindrical housing with a pattern 302 formed on it. The pattern 302 in Figure 3 is an example of a vertically oriented black and white striped pattern. The calibrator 301 can be shaped like a flat plate or a cylinder, or even a rectangular parallelepiped. Regardless of the shape, the pattern 302 is formed on the surface of the housing. If the shape of the calibrator 301 is the same as or similar to that of the container for the biological sample 102, the computational load for calculating the distortion coefficient and the liquid level conversion coefficient can be reduced.

[0060] The material of the housing of the calibrator 301 is a material such as resin or plastic that transmits at least one wavelength of the surface illumination light source 104 of the biological sample measuring device 101. The pattern 302 can be a pattern printed directly on the housing, or a pattern obtained by pasting a pattern 302 printed on paper on the surface of the housing. It can also be formed on the housing by other appropriate methods. The calibration data acquisition unit 107 analyzes the contrast of the pattern 302 acquired by the area camera 105, so that the pattern 302 is composed of an area that transmits the wavelength of the surface illumination light source 104 and an area that does not transmit it. By calculating each coefficient using the light transmitted from the calibrator 301, the device settings used when photographing the calibrator 301 (the position of the photographed object, the optical structure, etc.) can also be used directly when photographing the sample.

[0061] Figure 4A and Figure 4B 302 is a diagram showing an example of the pattern 302 . Figure 3A and Figure 4A The duty ratios of light and dark are different. Pattern 302 is a pattern with light and dark in the vertical direction. Figure 4A striped pattern, Figure 4B As long as the stripe spacing [mm] of pattern 302 is known, it does not need to be a stripe or grid pattern, and the duty ratio of black and white can be arbitrary. When using a stripe or grid pattern that alternates between light and dark at equal intervals, the amount of computation required for the distortion coefficient acquisition process performed by calibration data acquisition unit 107 is small. A random pattern is also acceptable as long as the pattern is known.

[0062] The printing range of the pattern 302 is set to cover the vertical area of ​​the imaged biological sample 102. The pattern 302 must exist within a range at least larger than the height of the measurement target area 103. Specifically, when the area camera 105 images a 90 mm area of ​​a 100 mm long blood collection tube, the pattern 302 only needs to be present across the entire vertical field of view of the area camera 105. If the range of the image analyzed by the liquid volume measurement unit 108 is narrower than the field of view of the area camera 105, aligning the printing range with the analysis range of the liquid volume measurement unit 108 can reduce the computational complexity of the distortion coefficient acquisition process by the calibration data acquisition unit 107.

[0063] Figure 5This figure illustrates a method for imaging etalon 301. Etalon 301 is positioned parallel to the lens surface of area camera 105. Area camera 105 captures the transmitted light from surface illumination source 104 illuminating etalon 301. The light illuminating etalon 301 can be a single wavelength. When using surface illumination source 104 illuminating two wavelengths, such as 970 nm and 1550 nm, imaging etalon 301 with the shorter wavelength (970 nm), which minimizes blurring due to aberrations, improves the contrast of pattern 302 and enables high-precision analysis.

[0064] The calibrator 301 can be positioned at any position as long as the distance from the area camera 105 to the calibrator 301 is known. If the calibrator 301 position is aligned with the imaging position of the biological sample 102, the amount of computation required to obtain the distortion coefficient and the liquid level conversion coefficient can be reduced.

[0065] <Implementation 1: Image Distortion Correction Method Based on Lens Aberration>

[0066] Figure 6A and Figure 6B A diagram illustrating distortion of a captured image. Figure 6A is used Figure 5 FIG. 6 is an explanatory diagram of an aligner image 601 obtained by capturing an aligner 301 having a constant interval between light and dark stripes. Figure 6B It is shown in Figure 6A Graph showing the distribution of the number of fringe interval pixels [pixels] when lens distortion exists in the analysis range 602. Figure 6B The horizontal axis represents the vertical coordinate of the calibrator image 601, and the vertical axis represents the number of pixels [pixel] between the light and dark stripes.

[0067] When photographing the calibrator 301 with a constant stripe interval of a light and dark pattern, the stripe interval is also not constant in the presence of lens distortion, such as Figure 6B The image is captured so that the number of pixels of the fringe interval decreases toward the edge of the image. The distribution of the fringe intervals of the calibrator 301 in this manner indicates the distortion of the image.

[0068] Figure 7 It means Figure 6BThe figure shows the liquid level conversion coefficient [mm / pixel] obtained by dividing the actual stripe interval length [mm] by the stripe period [pixel]. The number of stripe interval pixels changes according to the distortion of the image, so the liquid level conversion coefficient also becomes a distribution that depends on the coordinates in the vertical direction. That is, the liquid level conversion coefficient is different depending on the liquid level position of the biological sample 102. If the liquid level conversion coefficient obtained based on the stripe period at the center of the image is directly used in the conversion of the number of liquid level pixels at the end of the image, the accuracy of the liquid level will be reduced. In order to obtain the liquid level [mm] with high accuracy, it is necessary to consider Figure 6B and Figure 7 The distribution of liquid level height is used to transform the number of pixels.

[0069] The distortion coefficient calculation unit 109 obtains the distortion coefficient indicating the above-mentioned distortion. The liquid level conversion coefficient calculation unit 110 obtains the liquid level conversion coefficient based on the distortion coefficient. A specific method is described below.

[0070] Figure 8 This flowchart shows the process by which the distortion coefficient calculation unit 109 obtains distortion coefficients. A calibrator image 601 captured by the area camera 105 is obtained (S801). Based on the brightness distribution of an analysis range 602 set in the center of the image, a vertical fringe period distribution, as shown in Figure 6, is obtained (S802). The width of the analysis range 602 is set to a maximum of approximately the diameter of the blood collection tube. The fringe period distribution is obtained by averaging the pixel values ​​in the horizontal direction of the analysis range 602, thereby reducing the influence of noise. Distortion coefficients are obtained by fitting the obtained fringe period distribution to a distortion function (S803). Equation 1 is an example of a distortion function. yd represents the distortion function, y represents the vertical coordinate, and k1 and k2 represent the distortion coefficients. The distortion coefficients are set to minimize the error between Equation 1 and the fringe period distribution obtained in S802, and the obtained distortion coefficients are stored in the calibration data storage unit 111 (S804).

[0071] Since only vertical distortion (the liquid level height direction) affects liquid level accuracy, horizontal distortion can be disregarded. The distortion function can be a single direction with the vertical coordinate as a variable. When performing blood collection tube diameter detection (described later), a horizontal distortion function can also be calculated, or the vertical distortion function can be used as the horizontal distortion function. Calculating only a single distortion function reduces computational complexity.

[0072] [Formula 1]

[0073]

[0074] The liquid level conversion coefficient calculation unit 110 obtains the liquid level conversion coefficient based on the distortion coefficient stored in the calibration data storage unit 111 . Figure 9 and Figure 10 This is a flowchart illustrating a method for obtaining a liquid level conversion coefficient. There are two methods for obtaining a liquid level conversion coefficient by taking image distortion into consideration. The first method is to correct the distortion of the calibrator image 601. Figure 6B Method for obtaining constant liquid level transformation coefficient based on fringe period distribution ( Figure 9 The second method is to find the distribution of the liquid level transformation coefficient based on the distortion function ( Figure 10 ).

[0075] Figure 9 This is a flowchart illustrating a method for obtaining a liquid level conversion coefficient based on the distortion correction of the calibrator image 601. First, the calibrator image 601 and the distortion coefficient stored in the calibration data storage unit 111 are obtained (S901). Next, according to the distortion function defined by the equation 1, etc. using the distortion coefficient, the pixel interval is expanded or reduced, thereby performing distortion correction in the vertical direction of the calibrator image (S902). Next, the light and dark cycle distribution of the calibrator image 601 to which the distortion correction is applied is obtained (S903). Through the processing of S902, the light and dark cycle distribution obtained in S903 is obtained. Figure 6B The distribution of the light and dark cycles is flattened to match the actual distribution of the calibrator period. Finally, the actual calibrator period [mm] is divided by the light and dark period [pixel] to obtain a constant liquid level height conversion coefficient [mm / pixel] (S904) and store it in the calibration data storage unit 111 (S905). In S902, the distortion of the calibrator image 601 is corrected. However, correction can also be performed on the vertical fringe period distribution instead of the calibrator image 601 using a distortion function.

[0076] Figure 10 It is based on Figure 8 Flowchart of a method for obtaining a liquid level conversion coefficient as a distribution (function) with vertical coordinates as variables using the distortion coefficient and distortion function obtained in

[100] . First, the calibrator image 601 and the distortion coefficient are obtained (S1001), and a reference value of the liquid level conversion coefficient is obtained using a fringe period equal to the central area of ​​the calibrator image 601 (S1002). Next, the liquid level conversion coefficient is set based on the distortion coefficient. Figure 8 The distortion function is calculated, and using the inverse of the distortion function, the distribution of the liquid level conversion coefficients is obtained after the reference value of the liquid level conversion coefficients is corrected to depend on the vertical coordinates (S1003). The obtained distribution of the liquid level conversion coefficients is similarly stored in the calibration data storage unit 111 (S1004).

[0077] Figure 9 and Figure 10 Either method can obtain the liquid level conversion coefficient that takes into account image distortion. Just install and execute one of the methods. Figure 9 and Figure 10 In either case, the content of the stored liquid level conversion coefficient is different, and the flow of the liquid amount measurement process described later is also different.

[0078] The above process is pre-performed as calibration for each device. When measuring the volume of biological sample 102, the distortion coefficient and liquid level conversion coefficient stored in calibration data storage 111 are retrieved to determine the liquid level. This prevents deviations in working distance due to installation and other factors, as well as reductions in liquid level measurement accuracy due to image distortion.

[0079] <Implementation 1: Liquid Amount Measurement Method>

[0080] Figure 11 and Figure 12 This is a flowchart illustrating a process of measuring the liquid amount by the liquid amount measuring unit 108 . Figure 11 Is used through Figure 9 The method of obtaining the liquid level conversion coefficient is as follows: Figure 12 Is used through Figure 10 The method of obtaining the distribution of the liquid level conversion coefficient by the method of the liquid level conversion coefficient calculation unit 110 can be used according to the processing content ( Figure 9 or Figure 10 ) to switch to using Figure 11 and Figure 12 Which one of them.

[0081] Figure 11 It is used in Figure 9 Flowchart of the method for measuring liquid volume using the constant liquid level conversion coefficient obtained in . The liquid volume measuring unit 108 obtains the image of the biological sample 102 obtained by the area camera 105 (S1101), accesses the calibration data storage unit 111, and obtains the distortion coefficient and liquid level conversion coefficient (constant) (S1102). Next, using the distortion coefficient, Figure 9Image distortion of the captured image of the biological sample 102 is corrected using the same method as in S902 (S1103). Image distortion correction is performed at least in the vertical direction. When performing the blood collection tube diameter detection (described later), distortion correction in the horizontal direction is also performed, similar to the correction of the calibrator image 601. Based on the principle described in FIG2 , the measurement target region 103 is extracted from the biological sample image after image distortion correction by detecting the brightness gradient at the boundary (S1104). The number of vertical pixels in the extracted measurement target region is used as the number of liquid level pixels. The liquid level conversion coefficient obtained in S1102 is multiplied by the number of liquid level pixels to obtain the liquid level in mm (S1105). The liquid volume is calculated using the liquid level in mm and the blood collection tube diameter information (S1106). The blood collection tube information can be obtained from the blood collection tube used before the measurement, or from the image of the biological sample 102 using the method described later.

[0082] Figure 11 The measurement target region extraction process (S1104) can also acquire a one-dimensional luminance signal and detect the boundary of the measurement target region 103 by extracting a central region from the captured image of the biological sample 102. In this case, the one-dimensional luminance signal acquisition process can be performed on the distortion-corrected image output in the biological sample image distortion correction process (S1103), or the one-dimensional luminance signal acquisition process can be performed before S1103, and the distortion correction of S1103 can be performed on the acquired one-dimensional luminance signal. By performing distortion correction and measurement target region 103 extraction on the one-dimensional luminance signal, the amount of calculation can be reduced.

[0083] Figure 12 It is used in Figure 10 Flowchart of a method for measuring liquid volume using the distribution of liquid level height conversion coefficients obtained during processing. Figure 12 The processing and Figure 11 The processing is different from that of the biological sample 102. The distortion correction of the captured image obtained in S1201 is not performed. Figure 11 The same process as in S1104 is performed to extract the measurement target area (S1203). In S1204, the liquid level conversion coefficient corresponding to the coordinates (pixel units) of the measurement target area detected in S1203 is obtained based on the liquid level conversion coefficient distribution obtained in S1202, and the liquid level conversion coefficients are accumulated within the range of the measurement target area in the vertical direction to obtain the liquid level [mm]. Figure 11 Similarly, S1203 can also perform boundary detection on the one-dimensional brightness signal. Figure 11 Same as S1106.

[0084] Through the above Figure 11 and Figure 12 The processing can correct image distortion, so the liquid level height and liquid volume can be obtained with high precision.

[0085] <Implementation 1: Utilization of Blood Collection Tube Diameter>

[0086] As a factor affecting liquid level accuracy, we've discussed the influence of working distance variations on the liquid level conversion coefficient. However, in addition to variations caused by factors like device installation, working distance also varies depending on tube diameter, affecting liquid level measurement accuracy. For example, the distance from the camera to the tube surface varies by 1.5 mm between tubes with a diameter of 13 mm and 16 mm. One method for mitigating this effect is to prepare liquid level conversion coefficients corresponding to tube diameters and use them separately based on the tube diameter information obtained during measurement.

[0087] The following methods are considered for obtaining the liquid level conversion coefficient corresponding to the blood collection tube diameter: (a) Prepare in advance the same type of blood collection tube diameter as the blood collection tube diameter. Figure 3B (a) a cylindrical calibrator 301 is used to perform calibration, and the distortion coefficient and liquid level conversion coefficient corresponding to the diameter of the blood collection tube are obtained and stored; (b) considering the difference between the diameter of the calibrator 301 and the actual diameter of the blood collection tube, the liquid level conversion coefficient is obtained by scaling it up or down according to the ratio of their respective working distances, and is pre-stored in the calibration data storage unit 111, or the scaled liquid level conversion coefficient is obtained each time the liquid volume is measured.

[0088] In use Figure 3A In the case of such a planar calibrator 301, based on the ratio between the working distance when photographing the calibrator 301 and the working distance when photographing the biological sample 102 determined by the diameter of the blood collection tube, the value obtained by scaling the liquid level conversion coefficient obtained from the calibrator 301 is obtained as the liquid level conversion coefficient on the surface of the blood collection tube.

[0089] The liquid volume measuring unit 108 obtains blood collection tube information to determine the liquid volume based on the liquid level. The blood collection tube information may be pre-stored in the blood collection tube measuring unit 108, or the blood collection tube diameter may be detected during each measurement based on a captured image of the biological sample 102. In either case, obtaining the blood collection tube diameter during measurement enables the use of a liquid level conversion factor corresponding to the blood collection tube diameter. Methods for obtaining the blood collection tube diameter from a captured image of the biological sample 102 include methods for determining the diameter by detecting the boundary based on the brightness difference between the edge of the blood collection tube and the background.

[0090] <Implementation Method 2>

[0091] Figure 13 This is a structural diagram of a biological sample measurement device 101 according to Embodiment 2 of the present disclosure. In addition to the components described in Embodiment 1, this embodiment further includes an imaging position adjustment unit 1301, a gripping mechanism 1302, and a gripping mechanism control driver 1303. The remaining components are the same as those in Embodiment 1.

[0092] The gripping mechanism 1302 grips the biological sample 102 and the calibrator 301. The gripping mechanism control driver 1303 controls the position of the gripping mechanism 1302 based on the output of the imaging position adjustment unit 1301. The imaging position adjustment unit 1301 is composed of an imaging position storage unit 1304 and a biological sample imaging position acquisition unit 1305. The imaging position storage unit 1304 stores the imaging position of the calibrator 301 and the imaging position of the biological sample 102 acquired by the biological sample imaging position acquisition unit 1305. The biological sample imaging position acquisition unit 1305 acquires the imaging position information of the calibrator 301 stored in the imaging position storage unit 1304 and the liquid level conversion coefficient information stored in the calibration data storage unit, and uses these to acquire the imaging position of the biological sample 102.

[0093] exist Figure 13 In the embodiment, the shooting positions of the calibrator 301 and the biological sample 102 are adjusted by the holding mechanism 1302. However, the holding method may not be adopted. Instead, a clamp for fixing the biological sample 102 and the bottom of the calibrator 301 and a rail for adjusting the position of the clamp may be provided, and the shooting position may be adjusted by controlling the position of the clamp using a control driver.

[0094] <Implementation 2: Adjustment of the Equalizer and Biological Sample Shooting Position>

[0095] The liquid level conversion coefficient is determined by the working distance. Therefore, in order to obtain the liquid level with high accuracy, the imaging position of the pattern 302 surface of the etalon 301 needs to be aligned with the position of the measurement surface of the biological sample 102 .

[0096] When using a cylindrical calibrator 301 having the same diameter as the blood collection tube being measured, the imaging positions of the calibrator 301 and the biological sample 102 are aligned. The biological sample imaging position acquisition unit 1305 acquires the imaging position of the calibrator 301 stored in the imaging position storage unit 1304 and transmits the imaging position of the biological sample 102 to the gripping mechanism control driver 1303.

[0097] If the diameter of the calibrator 301 differs from the diameter of the blood collection tube, or if the position of the printed surface of the pattern 302 of the calibrator 301 deviates from the position of the measurement surface of the biological sample 102 due to a shape difference such as a plate-shaped calibrator, the biological sample imaging position acquisition unit 1305 acquires an imaging position that is offset from the imaging position of the calibrator 301 by the amount of the offset, and then images the biological sample 102 at this acquired imaging position. This allows the liquid level to be directly calculated using the distortion coefficient and liquid level conversion coefficient acquired through calibration. In this case, the liquid level conversion coefficient can also be corrected by scaling it up or down using the method described in Embodiment 1.

[0098] <Implementation Method 3>

[0099] In Embodiment 2, a method for adjusting the imaging position of the biological sample 102 based on the imaging position of the calibrator 301 was described. This method enables highly accurate measurement of the liquid level using an accurate liquid level conversion coefficient. On the other hand, if the position of the area camera 105 or the gripping mechanism 1302 deviates due to installation or other factors, the working distance of the biological sample 102 may vary between devices. This variation in working distance expands or contracts the field of view of the area camera 105, resulting in variations in resolution between devices.

[0100] In the third embodiment of the present disclosure, in order to solve this problem, Figure 13 In the configuration of , the imaging position of the biological sample 102 is adjusted based on the value of the liquid level conversion coefficient obtained by calibration. This allows a common working distance to be set between the devices.

[0101] Figure 14 It is a flowchart illustrating a method for adjusting the shooting position of the biological sample 102 according to the value of the liquid level conversion coefficient. First, the shooting image 1 of the calibrator 301 is obtained at the shooting position of the first point stored in the shooting position storage unit (S1401). Then, the holding mechanism controls the driver 1303 to move the calibrator 301 to the shooting position of the second point stored in the shooting position storage unit (S1402), and obtains the shooting image 2 (S1403). The shooting position of the second point is a position that deviates from the shooting position of the first point relative to the area camera 105 in the depth direction (either in the positive direction or the negative direction). For the shooting image 1 and the shooting image 2, the liquid level conversion coefficient is obtained by the method of embodiment 1, respectively. The acquisition method may be Figure 9 or Figure 10 Any of the methods in Figure 9 In the case of obtaining a constant liquid level height conversion coefficient, Figure 10In the case of , a reference value for calculating the distribution of the liquid level conversion coefficient is obtained (S1404). The biological sample shooting position acquisition unit 1305 sets a linear function with the horizontal axis as the coordinates of the shooting position and the vertical axis as the liquid level conversion coefficient based on the two liquid level conversion coefficients obtained (or the reference value of the liquid level conversion coefficient) and the coordinates of each shooting position (S1405). Based on the obtained linear function, the coordinates of the shooting position that can obtain the liquid level conversion coefficient shared by the devices are obtained (S1406). The obtained shooting position is stored in the shooting position storage unit 1304 and used when measuring the biological sample 102. By performing the above steps when calibrating each device, the biological sample 102 can be shot at a common working distance (and a common liquid level conversion coefficient) between the devices.

[0102] As an effect of imaging at a common working distance, in addition to being able to image at the same resolution between devices, it is also possible to reduce the focus deviation of the lens caused by the deviation of the working distance.

[0103] <Regarding Modifications of the Present Disclosure>

[0104] The present disclosure is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not limited to all structures described. In addition, a portion of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. In addition, with respect to a portion of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0105] The calibration in the first embodiment may be performed for each device when the device is installed, or may be performed using the calibrator 301 each time a measurement is performed.

[0106] In the first embodiment, a specific example of the wavelength for obtaining a transmission image is described by assuming the specific structure of the biological sample 102 (serum sample). The present disclosure is not limited to this and can also be applied to other types of samples. That is, by appropriately selecting the wavelength for obtaining a transmission image based on the absorbance characteristics of the sample, Figure 2A-2B The wavelength of the transmission image exemplified in FIG can be applied to other samples.

[0107] The calibration data acquisition unit 107 , the liquid volume measurement unit 108 , and the imaging position adjustment unit 1301 may be configured by hardware such as circuit devices implementing their functions, or by a computing device such as a CPU (Central Processing Unit) executing software implementing their functions.

[0108] In the above embodiment, the calibrator 301 may be a component of the biological sample measurement device 101 , or may be configured as a component separate from the biological sample measurement device 101 .

[0109] In the above embodiment, the steps of calculating the distortion coefficient and the liquid level conversion coefficient do not necessarily need to be performed when measuring the biological sample 102 . For example, they can be performed in advance before measuring the biological sample 102 and the results can be stored in the biological sample measuring device 101 .

[0110] Explanation of symbols

[0111] 101 Biological Sample Measurement Device

[0112] 104 lighting sources

[0113] 105 area cameras

[0114] 106 time-sharing control driver

[0115] 107 calibration data acquisition unit

[0116] 108 Liquid Volume Measurement Unit

[0117] 301 Calibrator

[0118] 1301 Shooting position adjustment unit.

Claims

1. A biological sample measuring device for measuring a biological sample having one or more component regions, characterized in that: The biological sample measuring device comprises: an imaging unit configured to generate a first captured image of the biological sample using light transmitted through the biological sample, and to generate a second captured image of the calibrator using light transmitted through an calibrator having a pattern formed on its surface; a distortion coefficient calculation unit that calculates a distortion coefficient for correcting distortion of the image captured by the imaging unit using the second captured image; a conversion coefficient calculation unit that calculates a conversion coefficient for converting the number of pixels in the image captured by the imaging unit into a length using the distortion coefficient; as well as A liquid volume measuring unit measures the liquid level of the biological sample by applying the conversion coefficient to the first captured image.

2. The biological sample measuring device according to claim 1, wherein The liquid amount measuring unit is configured to identify a target portion of the biological sample as a measurement target from a captured image of the biological sample. The imaging unit generates a third captured image of the biological sample using a first wavelength component of the light transmitted through the biological sample. The imaging unit generates a fourth captured image of the biological sample using a second wavelength component of the light transmitted through the biological sample. The liquid amount measuring unit determines an amount resulting from a difference between a portion of the third captured image generated using the first wavelength component and a portion of the fourth captured image generated using the second wavelength component. The liquid amount measuring unit determines the range of the target portion by determining a portion where the determined amount is equal to or greater than a threshold value.

3. The biological sample measuring device according to claim 1, wherein The pattern shape is composed of a plurality of shapes arranged along the height direction of the liquid surface of the biological sample.

4. The biological sample measuring device according to claim 1, wherein The biological sample measurement device further includes a light source configured to irradiate the etalon and the biological sample with first light having a first wavelength component or second light having a second wavelength component. The light source irradiates the etalon with the light having the shorter wavelength among the first light and the second light. The imaging unit generates the second captured image using the light transmitted through the calibrator.

5. The biological sample measuring device according to claim 1, wherein The conversion coefficient calculation unit calculates the conversion coefficient for each position in the liquid level height direction of the biological sample. The liquid volume measuring unit measures the liquid level of the biological sample by applying the conversion coefficient corresponding to the position of the first captured image in the liquid level height direction.

6. The biological sample measuring device according to claim 1, wherein The pattern shape is composed of a plurality of shapes periodically arranged along the liquid level direction of the biological sample, The distortion coefficient calculation unit obtains the period of the pattern shape in the second captured image for each position in the liquid surface height direction. The distortion coefficient calculation unit obtains a distortion function representing the distortion by performing function fitting on the period of the pattern shape obtained from the second captured image. The distortion coefficient calculation section uses parameters constituting the distortion function as the distortion coefficient.

7. The biological sample measuring device according to claim 1, wherein The conversion coefficient calculation unit corrects the distortion of the second captured image using the distortion coefficient. The conversion coefficient calculation unit calculates the conversion coefficient by dividing an actual size of the pattern shape of the calibrator by the number of pixels of the pattern shape of the corrected second captured image.

8. The biological sample measuring device according to claim 1, wherein The distortion coefficient calculation unit calculates the distortion coefficient for distortion that depends on the position of the biological sample in the liquid level height direction. The conversion coefficient calculation unit obtains a reference value of the conversion coefficient by dividing the actual size of the pattern shape of the calibrator by the number of pixels of the pattern shape of the second captured image at a reference position of the second captured image. The conversion coefficient calculation unit calculates the conversion coefficient that changes depending on the position in the liquid level height direction by applying a function constructed using the distortion coefficient to the reference value.

9. The biological sample measuring device according to claim 1, wherein The liquid amount measuring unit corrects the distortion of the first captured image using the distortion coefficient. The liquid volume measuring unit measures the liquid level of the biological sample by applying the conversion coefficient to the corrected first captured image.

10. The biological sample measuring device according to claim 8, wherein The liquid volume measuring unit measures the liquid level of the biological sample by applying a value corresponding to a position in the liquid level direction of the first captured image, among the conversion coefficients calculated for each position in the liquid level direction.

11. The biological sample measuring device according to claim 1, wherein The conversion coefficient calculation unit calculates the conversion coefficient according to the size of the container using the second captured image of each of the plurality of calibrators having different sizes according to the size of the container containing the biological sample. or, The conversion coefficient calculation unit enlarges or reduces the conversion coefficient obtained based on the second captured image according to a ratio between a working distance when the imaging unit captures the second captured image and a working distance when the imaging unit captures the first captured image.

12. The biological sample measuring device according to claim 1, wherein The biological sample measurement device further includes a position adjustment unit that adjusts the position of the object imaged by the imaging unit. The position adjustment unit adjusts the position of the biological sample so that the position of the pattern shape when the second captured image for calculating the distortion coefficient and the transformation coefficient is captured is the same as the position of the measured surface of the biological sample when the first captured image for applying the distortion coefficient and the transformation coefficient is captured.

13. The biological sample measuring device according to claim 1, wherein The biological sample measurement device further includes a position adjustment unit that adjusts the position of the object imaged by the imaging unit. The photographing unit photographs an image of the calibrator when the calibrator is in the first position. When the calibrator is at a second position different from the first position in the depth direction, the imaging unit captures an image of the calibrator. The transform coefficient calculation unit calculates a first coefficient at the first position and a second coefficient at the second position as the transform coefficients, The conversion coefficient calculation unit calculates a function representing the relationship between the position of the etalon and the conversion coefficient using the first coefficient and the second coefficient. The conversion coefficient calculation unit determines, from the relationship described by the function, a pair of the conversion coefficient and the position of the biological sample, which is commonly used for each of the biological sample measurement devices. The position adjustment unit arranges the biological sample at the position determined by the pair, and the liquid volume measurement unit uses the conversion coefficient determined by the pair.

14. The biological sample measuring device according to claim 1, wherein The container for storing the biological sample and the calibrator have the same shape or a similar shape.

15. A calibration method for calibrating a biological sample measuring device for measuring a biological sample having one or more component regions, characterized in that: The calibration method has the following steps: generating a captured image of an etalon using transmitted light transmitted through an etalon having a patterned shape formed on a surface thereof; calculating, using the captured image, a distortion coefficient for correcting distortion of the image captured by the biological sample measurement device; as well as Using the distortion coefficient, a conversion coefficient for converting the number of pixels in the image captured by the biological sample measurement device into a length is calculated.

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