Methods and apparatus for providing background illumination calibration for sample and / or sample container characterization

Abstract

A calibration method is provided that includes identifying an imaging area on each light panel with respect to each imaging device. A center position of the imaging area of each light panel is determined for each imaging device. The center position of the imaging area of each imaging device is used to determine an optimal optical center of the imaging equipment. A tube calibration tool is installed in a carrier on a track and the carrier is moved on the track such that a center of the tube calibration tool is located at a position closest to the optimal optical center of the imaging equipment. The center of the tube calibration tool is used to determine a center of a region of interest (ROI) for backlight calibration. Methods and apparatus for performing calibration and other aspects for health checking calibration are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 929,058, entitled “METHODS AND APPARATUS PROVIDING CALIBRATION OF BACKGROUND ILLUMINATION FOR SAMPLE AND / OR SAMPLE CONTAINER CHARACTERIZATION,” filed October 31, 2019, the disclosure of which is hereby incorporated by reference in its entirety for all purposes. TECHNICAL FIELD

[0003] The present disclosure relates to imaging methods and imaging apparatuses adapted to image sample tubes (specimen containers), and more particularly, to methods and apparatuses for calibrating imaging apparatuses. BACKGROUND

[0004] Automated testing systems can perform clinical chemistry or assays using one or more reagents and / or other materials to identify analytes or other constituents in biological samples, such as serum, plasma, urine, interstitial fluid, cerebrospinal fluid, etc. For convenience and safety reasons, these samples are almost always contained in sample tubes (e.g., blood collection tubes). Each sample tube can be capped with a cap, and in some cases, these caps can include a cap color and / or cap type that can provide information about the type of test to be performed on it, the type of additive contained in the tube (e.g., a serum separator, a coagulant such as thrombin, or an anticoagulant and its specific type, like EDTA, K2EDTA, or sodium citrate, and / or an anti-glycosis additive), whether the tube was provided with vacuum capability, etc.

[0005] Improvements in automated testing are accompanied by corresponding advances in automated pre-analytic sample handling, such as batch preparation, sample centrifugation for separating sample components, cap removal (decapping) to facilitate sample access, aliquot preparation, pre-screening for hemolysis (H), icterus (I), and / or lipemia (L) (hereinafter referred to as "HIL") or normality (N), and pre-screening for other artifacts such as clots, foam, or bubbles. Such automated pre-analytic sample handling can be part of a laboratory automation system (LAS). In some cases, a LAS automatically transports samples contained in sample tubes for pre-analytic sample handling, and to an analysis station containing a clinical chemistry analyzer and / or assay instrument (herein referred to individually and collectively as "analyzer" or "analyzers") for testing. The testing involves generating a reaction that changes, which can be read and / or otherwise manipulated to determine the concentration of an analyte or other component contained in the sample.

[0006] A LAS can handle any number of different samples contained in labeled sample tubes (e.g., including bar code labels) at one time, and the sample tubes can have all different sizes and tube assembly types, including different cap styles (shapes) and colors, which can also be intermingled. A LAS can automatically transport sample tubes for pre-analytic handling operations, all of which are performed prior to the sample actually undergoing clinical analysis or assay by one or more analyzers.

[0007] In some embodiments of automated pre-analytic sample handling, a quality check module can receive a sample tube containing a sample therein, and pre-screen the sample for the presence of an interferent, such as HIL. Pre-screening for HIL involves capturing one or more digital images of the sample tube and sample, and then processing the image data to determine whether H, I, and / or L is present, and possibly, if present, the index (relative amount) of H, I, and / or L, or it can be determined that the sample is normal (N). The presence of an interferent in the sample can adversely affect the test results of analyte or component measurements obtained later from an analyzer.

[0008] In certain apparatus, such as with a computer-aided model-based system (such as by using artificial intelligence (e.g., convolutional neural network - CNN)), the sample container and sample are digitally imaged and processed so that the presence or absence of an interferent (HIL or N) can be determined. The type and color of the cap can also be discerned. During imaging, images of the sample tube (including cap) and sample can be captured from multiple viewpoints.

[0009] However, under certain conditions, such equipment can produce performance variations and even from one system to the next. Accordingly, improved methods and apparatus for imaging such samples and / or sample containers are sought. SUMMARY

[0010] According to a first aspect, a calibration method is provided. The calibration method includes identifying an imaging area on each light panel with respect to each imaging device; determining a center position of the imaging area of each light panel for each imaging device; determining an optimal optical center of the imaging apparatus using the center position of each light panel for each imaging device; installing a tube calibration tool in a carrier residing on a track; moving the carrier on the track such that a center of the tube calibration tool is located at a position closest to the optimal optical center of the imaging apparatus; and determining a center of a region of interest (ROI) for back light calibration using the center of the tube calibration tool.

[0011] According to another aspect, a light panel calibration method is provided. The light panel calibration method includes turning on a first driving current to a plurality of light elements of a light panel on a first side closest to a region of interest; adjusting the first driving current to the plurality of light elements of the light source on the first side until a representative intensity at the region of interest reaches a preset value; and adjusting a driving current to a plurality of light elements of the light source on a second side until a representative intensity of the ROI reaches a second preset intensity value, with the driving current still being driven to the plurality of light elements of the light source on the first side.

[0012] Still other aspects, features, and advantages of the disclosure can be readily apparent from the following description, by illustrating a number of example embodiments. The application can also be capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the scope of the present disclosure. Additionally, although a particular advantage can have been listed, various embodiments can include all, some, or none of the listed advantages. The disclosure is to be construed as covering all modifications, equivalents, and alternatives falling within the scope of the claims. BRIEF DESCRIPTION OF DRAWINGS

[0013] The drawings described below are for illustrative purposes and are not necessarily drawn to scale. The drawings are intended to be explanatory and not limiting of the scope of the application. Thus, the drawings are considered to be illustrative in nature and not restrictive in nature.

[0014] Figure 1 A top perspective schematic view of a quality inspection apparatus including an imaging apparatus is illustrated, with which a calibration method according to one or more embodiments is used.

[0015] Figure 2A side plan view of a sample tube containing a separated (e.g., centrifuged) sample is illustrated.

[0016] Figure 3 A side plan view of a sample container containing a separated (e.g., centrifuged) sample and further including a gel separator is illustrated.

[0017] Figure 4A A top view of a quality check apparatus according to one or more embodiments is illustrated with the top removed for illustration purposes and including an imaging apparatus and a sample tube including a sample to be characterized at an imaging location.

[0018] Figure 4B A front perspective view of an imaging apparatus of a quality check apparatus according to one or more embodiments is illustrated with the housing removed for illustration purposes and including a plate light source and a sample tube mounted in a carrier at an imaging location.

[0019] Figure 4C A perspective view of a tube calibration tool mounted in another embodiment of a carrier according to one or more embodiments is illustrated.

[0020] Figure 4D A side view of a tube calibration tool including a stepped configuration according to one or more embodiments is illustrated. Figure 4C

[0021] Figure 5A A top view schematic of an imaging apparatus of a quality check apparatus according to one or more embodiments is illustrated with the housing removed for illustration purposes and illustrating a mechanical center and an optimal optical center.

[0022] Figure 5B A pixelated image taken by imaging device 106B according to one or more embodiments is illustrated including an optical region positioned on light panel 104B and located at the lateral geometric center of the image and vertically spanning the height of the panel.

[0023] Figure 5C A pixelated image taken by imaging device 106A according to one or more embodiments is illustrated including an optical region positioned on light source 104A and located at the lateral geometric center of the image and vertically spanning the height of the panel.

[0024] Figure 5D A pixelated image taken by imaging device 106C according to one or more embodiments is illustrated including an optical region positioned on light panel 104C and located at the lateral geometric center of the image and vertically spanning the height of the panel. ​

[0025] Figure 5E A pixelated image taken by imaging device 106B, including masked regions formed by the LCD mask on light panel 104B, and illustrating the second optical region (unmasked region) of the image, is illustrated in accordance with one or more embodiments.

[0026] Figure 5F A pixelated image taken by imaging device 106C, including masked regions formed by the LCD mask on light panel 104C, and illustrating the second optical region (unmasked region) of the image, is illustrated in accordance with one or more embodiments.

[0027] Figure 5G A pixelated image taken by imaging device 106A, including masked regions formed by the LCD mask on light source 104A (light panel), and illustrating the second optical region (unmasked region) of the image, is illustrated in accordance with one or more embodiments.

[0028] Figure 5H A pixelated image taken by imaging device 106B, including a calibration tool housed in a carrier, where the calibration tool is positioned as close to the optimal optical center as possible, is illustrated in accordance with one or more embodiments.

[0029] Figure 5I A pixelated image taken by imaging device 106C, including a calibration tool housed in a carrier, where the calibration tool is positioned as close to the optimal optical center as possible, is illustrated in accordance with one or more embodiments.

[0030] Figure 5J A pixelated image taken by imaging device 106A, including a calibration tool housed in a carrier, where the calibration tool is positioned as close to the optimal optical center as possible, is illustrated in accordance with one or more embodiments.

[0031] Figure 6 A flowchart of a calibration method adapted to calibrate an imaging apparatus, in accordance with one or more embodiments, is illustrated.

[0032] Figure 7A A flowchart of a calibration method adapted to calibrate a light panel, in accordance with one or more embodiments, is illustrated.

[0033] Figure 7B A schematic front view of a light panel including a plurality of light elements on its respective lateral sides, in accordance with one or more embodiments, is illustrated.

[0034] Figure 7B' A schematic front view of a light panel including an LCD mask, in accordance with one or more embodiments, is illustrated.

[0035] Figure 7C FIG. 3 illustrates a front view pixelated image of the light panel 104B taken by the imaging device 106B after illumination of the plurality of light elements on the first side of the light panel 104B, according to one or more embodiments.

[0036] Figure 7D FIG. 4 illustrates a front view pixelated image of the light panel 104B taken by the imaging device 106B after illumination of the plurality of light elements on the first and second sides of the light panel 104B, according to one or more embodiments.

[0037] Figure 8 FIG. 5 illustrates a pixelated image of the locations of a plurality of off-center regions of interest (ROIs) (single-dotted line and dash-dot line boxes) and a center ROI (solid box), where the numbers within each ROI are the ratios of their average intensities compared to the average intensity of the center ROI, expressed as a percentage, according to one or more embodiments. DETAILED DESCRIPTION

[0038] Background illumination calibration is used to accomplish sample tube quality checks, particularly to check for the presence of interferents such as hemolysis, icterus, hyperlipidemia (HIL) based on the color of the liquid (e.g., serum or plasma fraction) contained in the sample container. In this disclosure, methods and apparatus are provided to perform background illumination calibration of the imaging device within a sample tube quality check apparatus to ensure substantially consistent illumination across multiple spectrums and multiple machines (e.g., sample tube quality check apparatuses). Consistent background illumination can be achieved because the mechanical center is identified for each setup so that the center of the region of interest (ROI) for each light panel is obtained. As such, the method can be used to adjust the current to achieve a predefined intensity value within the ROI to provide substantially consistent background illumination across multiple spectrums and multiple machines. Embodiments provide methods for finding the mechanical center in order to extrapolate the ROI for each light panel. In other embodiments, methods for adjusting the drive current to the side-lighted light panel are provided.

[0039] With consistent illumination across multiple quality check apparatuses (machines), sample tube quality check functions such as HIL interference screening based on fluid color distribution can be made more accurate. This is useful to save time and resources for HIL testing, such as on an analyzer.

[0040] In particular, the present disclosure relates to a method for calibrating background illumination in a sample tube quality check apparatus, which can involve illumination with various light spectrums. Further, the sample tube quality check apparatus can involve illuminating a sample tube and a sample therein with light sources comprising backlights, which comprise light elements (e.g., LEDs) that are illuminated from both sides (e.g., lateral sides) of the respective backlight. Possible alternative solutions can involve manually measuring the brightness with a light meter, and / or manually measuring the color distribution at the sample tube illumination area (hereinafter, imaging location) with a spectrometer. During the plate calibration, the driving current / voltage of the background illumination source can be adjusted. Optionally, the exposure of the sensor can be adjusted.

[0041] According to embodiments, the present disclosure relates to a method and apparatus arranged and used to perform calibration of background illumination within a sample tube characterization apparatus (e.g., a quality check apparatus), such as to ensure consistent and accurate background illumination. Improving the background illumination calibration can improve the discrimination power with respect to, for example, HILN detection and / or artifact detection (foam, air bubble(s) or clot(s)) in a sample.

[0042] In some embodiments, the present disclosure relates to a method and apparatus arranged and used to perform background illumination calibration across multiple sample tube characterization apparatuses (e.g., across multiple quality check apparatuses or similar machines). Background illumination as used herein means illuminating the back / sides of a sample tube by one or more illumination sources positioned at one or more locations behind the sample tube, and with an imaging device located in front of the sample tube. For example, in some embodiments, the background illumination can comprise background light from one or more illumination devices (e.g., one or more light panels), which can be located behind the sample tube, i.e., the sample tube is located between the light source and the corresponding imaging device.

[0043] Further, embodiments of the present disclosure provide a method and apparatus configured to calibrate a back illumination device of an imaging device so that the imaging device can capture one or more images of a sample tube and a sample therein, where the one or more captured images can be used to characterize one or more features of the sample, such as, for example, the presence of HILN and / or artifacts. In a quality check apparatus, the check of the quality of the test sample is utilized to ensure the appropriateness of one or more tests performed on the sample. For example, if the sample contains H, I, and / or L, an error can be flagged, and the sample can be redrawn and / or further processed to improve the interferents. Thus, improved background illumination can improve the characterization of the sample. Thus, if an abnormality in the sample is identified, the sample can be diverted before being sent to an analyzer, thereby saving analyzer resources and possibly avoiding a test that can produce an erroneous result.

[0044] In particular, embodiments of the present disclosure relate to a calibration apparatus and calibration method configured to provide improved image data from one or more imaging devices that have been properly calibrated. In further embodiments, methods and apparatuses are provided that are capable of quickly calibrating one or more similar imaging devices (e.g., substantial clones).

[0045] Reference is now made to Figure 2 and Figure 3 In some embodiments, a sample 212 (test sample) as described herein is collected in a sample tube 102 (such as a blood collection tube) and can include a settled blood portion 212SB after separation (e.g., after fractionation using centrifugation) as well as a serum and plasma portion 212SP as shown. The settled blood portion (sometimes referred to as a “packed cell portion”) is composed of blood cells (such as white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes)) that have aggregated and separated from the serum or plasma portion 212SP. The settled blood portion 212SB is typically found at the bottom portion of the sample tube 102. The serum or plasma portion 212SP is the liquid component of blood that is not part of the settled blood portion 212SB. It is typically found above the settled blood portion 212SB. The main difference between plasma and serum is the content of clotting components (mainly fibrinogen). Plasma is the unclotted liquid, while serum refers to plasma that has been allowed to clot under the influence of endogenous enzymes or exogenous components or clotting agents.

[0046] In some sample tubes 102, a small gel separator 313 (such as, for example, a gel separator from the Vacutainer® brand of blood collection tubes) can be used to separate the settled blood portion 212SB from the serum and plasma portion 212SP. The gel separator 313 is a gelatinous substance that is contained in a small tube or container that is inserted into the sample tube 102. The gel separator 313 is designed to separate the settled blood portion 212SB from the serum and plasma portion 212SP. The gel separator 313 is typically inserted into the sample tube 102 at the time of collection of the sample 212. The gel separator 313 is designed to separate the settled blood portion 212SB from the serum and plasma portion 212SP. The gel separator 313 is typically inserted into the sample tube 102 at the time of collection of the sample 212. Figure 3The gel separator 313, which is shown in the plug, positions itself between the settled blood portion 212SB and the serum or plasma portion 212SP during fractionation. It acts as a barrier to prevent mixing between these two portions, and can be provided in the sample tube 102 prior to fractionation in a conventional manner.

[0047] Figure 1 Shown in FIG. 1 is an embodiment of a sample tube quality check apparatus 100 with which the background calibration method according to the present disclosure can be used. Figure 1 An example of an optical imaging apparatus 101 within the quality check apparatus 100 is shown, which includes a plurality of light sources 104A-104C (e.g., light panels) and a plurality of imaging devices 106A-106C. In some operations, the light sources 104A-104C are primarily used for back illumination of the sample tube 102 from the backside of the sample tube 102, so each of the respective imaging devices (e.g., photodetectors, charge-coupled devices (CCDs), digital cameras, complementary metal-oxide-semiconductor (CMOS) sensors, etc.) in front of the sample tube 102 can check the fluid properties of the sample 212 in the sample tube 102. The fluid properties can be, for example, HILN, volume or size of one or more components of the sample 212, and / or presence of artifacts (e.g., clots, foam, air bubbles) therein. Back illumination is the subject of this calibration method, as opposed to front illumination (front lighting).

[0048] For fluid quality checks (e.g., HIL interferant pre-screening), the light sources, including the back light panel, can utilize light-emitting diodes (LEDs) that emit various spectra, as different interferant types can behave differently across different spectra. As each quality check apparatus 100 (e.g., machine) can have slightly different set-up imaging devices (e.g., cameras, sensors, etc.), back light panels, and sample tube tracks, the background illumination calibration should account for some or all of these variations to ensure consistent observation within the quality check apparatus 100 and across multiple other quality check apparatuses (other machines).

[0049] To this end, according to a first aspect of the background calibration method, it is proposed that the background illumination be performed in multiple stages:

[0050] (1) optical centering,

[0051] (2) mechanical centering, and

[0052] (3) LED adjustment.

[0053] Subsequently, an LED health check can be performed. This check may involve examining the local intensity of one or more other areas (or multiple other areas) on the backlight panel and comparing these local intensity values ​​with pre-established intensity values ​​for the region of interest (ROI). This health check of the other areas can determine when one or more areas may fail. Achieving consistent background illumination for a single quality inspection device 100, and particularly across multiple imaging quality inspection devices (such as quality inspection device 100), ensures appropriate and consistent performance and sample characterization. Further health checks can potentially identify defective areas in the backlight panel and / or imaging device.

[0054] like Figure 1 As shown, light sources 104A-104C and imaging devices 106A-106C can be arranged to provide lateral 2D images of the sample container 102 and the sample 212 contained therein from one or more different lateral viewpoints (e.g., the three viewpoints 1, 2, and 3 shown). More or fewer viewpoints can be used. During image capture for sample characterization, the sample container 102 and sample 212 can be backlit, i.e., illuminated behind the sample container 102 and sample 212. For example, background illumination can be provided for imaging device 106A by light source 104A (e.g., a light plate), for imaging device 106B by light source 104B (e.g., a light plate), and for imaging device 106C by light source 104C (e.g., a light plate). Backlighting using light sources 104A-104C (e.g., a light plate) can be coupled with high dynamic range (HDR) image processing and its handling of images acquired by imaging devices 106A-106C. Any suitable characterization method can be used to quantify and characterize sample 212, where the characterization involves quantifying the intensity of light transmitted through sample 212 at various spatial locations within the image window. The imaging window should be large enough to capture an image of the portion to be characterized, such as serum or plasma fraction 212SP, sedimented blood fraction 1212SB, or gel separator 313 (see [link to image]). Figures 2-3 ).

[0055] In some embodiments, the characterization method and apparatus can be used to determine the location of the interface boundary of the serum or plasma portion 212SP and / or the settled blood portion 212SB and / or the gel separator 313, as well as the volume and / or depth of these components, with high precision using image processing (e.g., HDR image processing) along with background illumination. In short, the illuminated 2D image data sets for one or more viewpoints (e.g., viewpoints 1-3) can be used to characterize the sample 212. In particular, the 2D image data sets obtained with background lighting by the light sources 104A-104C can also be used to determine information about the sample 212, such as whether the sample has the presence of interferences (such as hemolysis (H), icterus (I), and / or lipemia (L) (hereinafter "HIL")), or whether the sample is normal (N), or even the presence of artifacts (e.g., clots, foam, or bubbles) therein.

[0056] Referring again to Figure 1 In one or more embodiments, the quality check module 100 can be provided as part of a LAS. The LAS can include a track 108 (only a portion of which is shown) that functions to transport the sample containers 102 including the samples 212 to one or more analyzers (not shown), as well as to the quality check module 100 provided at any suitable location on or along the track 108. For example, the quality check module 100 can be located at a loading station, adjacent to an analyzer or as part of an analyzer, or elsewhere along the track 108 so that the samples 212 and sample containers 102 can be pre-screened and characterized. In certain embodiments, the characterization can be performed while the sample containers 102 reside on a carrier 122 that is movable along the track 108. However, for clarity, the quality check module 100 including the background lighting can not be included on the track 108, and the sample containers 102 including the samples 212 can be loaded and unloaded from the quality check module 100, for example, either manually or with robotic action. For example, a robot can unload the sample containers from a loading station, centrifuge them, place them into a holder of the quality check module next to the loading station or track 108, and then place the sample containers 102 into a carrier on the track 108 after imaging to complete the pre-screening.

[0057] In some embodiments, the characterization can include data processing (e.g., data processing of HDR image processing) including capturing multiple images at multiple exposures (e.g., exposure times) and with background illumination. The image processing can involve using multiple different spectra with different nominal wavelengths. The multiple images can be obtained using the imaging devices 106A-106C for multiple viewpoints 1-3, and possibly with back illumination using multiple different spectra for each of the multiple viewpoints 1-3.

[0058] Platination illumination (e.g., using a light panel) can be used to produce images for each viewpoint 1-3. Spectral light sources for background illumination can include red (R) light sources, green (G) light sources, and blue (B) light sources. Optionally, white (W), near-infrared (NIR), or even infrared (IR) light sources can be used. The quality check module 100 can obtain images at multiple exposure times for each spectrum. For example, at each spectrum (or wavelength range), 4-8 images at different exposure times can be obtained. The computer 143 can then further process these multiple images to generate sample characterization results. Any suitable segmentation and / or characterization methods can be used.

[0059] As part of the image processing, calibration is performed to properly adjust the image intensity to ensure that the background lighting has the proper intensity for each spectrum (e.g., R, G, B, etc.) of light used for the illumination of each image capture device 106A-106C. Further details of the calibration method of the imaging apparatus 101 of the quality check module(s) 100 will be further described herein with reference to Figures 1-8

[0060] Typically, the samples 212 to be automatically processed (e.g., blood samples, urine samples, etc.) Figure 2 and 3 can be provided in the sample containers 102, which can be capped with a cap 214. The cap 214 can have different shapes and / or colors (e.g., red, royal blue, light blue, dark green, light green, black, gray, tan, orange, or yellow, or combinations of colors), which can have meaning in terms of what test the sample container 102 is used for, the type of additive contained therein, whether the specimen should be under vacuum, etc. Other colors can also be used. According to one aspect, it can be desirable to image the cap 214 to characterize information about the cap 214 so that it can be used for cross-checking with a test order and verifying that the correct sample tube 102 is used for the ordered test. For example, in some embodiments, the background lighting can be used to image the opacity of the cap 214.

[0061] ​Each sample container 102 can be provided with identification information 218i (i.e., indicia), such as a bar code, letters, numbers, alphanumeric, or combinations thereof, which can be machine-readable. For example, the identification information 218i can indicate, via a laboratory information system (LIS) 147, the identity of the patient and the tests to be performed on the sample 212, or other information from or otherwise associated with the laboratory information system (LIS). Such identification information 218i can generally be provided on a label 218 that is affixed to the sample container 102, or otherwise provided on the side of the sample container 102. The label 218 generally does not extend all the way around the sample container 102, or all the way along the height of the sample container 102. In some embodiments, multiple labels 218 can be affixed, and can slightly overlap one another. Thus, although the label 218 can obscure the view of some portions of the sample 212, other portions of the sample 212 can still be viewed from one or more of the viewpoints 1-3. One or more embodiments of the characterization method and quality check module 100 can enable characterization of the sample 212 by imaging the sample 212 from multiple viewpoints (e.g., viewpoints 1, 2, and 3, for example) without requiring undesirable rotation of the sample container 102. Other numbers of multiple viewpoints can be used.

[0062] As shown best in Figure 2 and 3 The sample 212 can include a serum or plasma portion 212SP and a settled blood portion 212SB contained within the tube 215, as shown best in Figure 2 The interface between the air 216 and the cap 214 is referred to herein as the tube-cap interface (TC). The height of the serum or plasma portion 212SP is (HSP), and is defined as the height from the top of the serum or plasma portion 212SP to the top of the settled blood portion 212SB. The height of the settled blood portion 212SB is (HSB), and is defined as the height from the bottom of the settled blood portion 212SB to the top of the settled blood portion 212SB at SB in Figure 2 HTOT in Figure 2 is the total height of the sample 212, and HTOT = HSP + HSB.

[0063] In cases where a gel separator 313 is used (see Figure 3The height of the serum or plasma fraction 212SP is (HSP), and is defined as the height from the top of the serum or plasma fraction 212SP at LA to the top of the gel separator 313 at SG. The height of the sedimented blood fraction 212SB is (HSB), and is defined as... Figure 3 The height from the bottom of the settled blood portion 212SB to the bottom of the gel separator 313 at BG. Figure 3 HTOT in the figure is the total height of sample 212 and is defined as HTOT = HSP + HSB + height of gel separator 313.

[0064] In each case, the wall thickness is Tw, the outer width is W, and the inner width of the sample container 102 is Wi. The height of the tube (HT) is defined herein as the height from the bottommost portion of the tube 215 to the bottom of the cap 214. Characterization methods using foreground and / or background lighting can be used to determine any of these geometric properties.

[0065] As discussed above, the carrier 122 can move the sample container 102 along the track 108 and stop at the imaging position 109 in the quality inspection device 100, such as Figure 1 and 4A As shown in -4B. The carrier 122 can be a passive, non-motorized disk configured to carry a single sample container 102 on a track 108, where the track 108 is movable, or the carrier 122 can be automated, including an onboard drive motor programmed to move around the track 108 and stop at pre-programmed locations, such as at imaging position 109. In either case, the carrier 122 may include a holder configured to hold the sample container 102 in a vertical orientation, allowing it to be easily moved, for example, from one viewpoint (…). Figure 4B ) or from multiple viewpoints 1-3 ( Figure 1 and 4A The sample container 102 is imaged. The retainer may include multiple fingers or leaf springs, combinations thereof, or other suitable mechanisms that support and secure the sample container 102 within the carrier 122, but some of these may be laterally movable or flexible to accommodate sample containers 102 of different sizes (diameters) to be housed therein.

[0066] The quality check apparatus 100 can be controlled by a computer 143, which can be a microprocessor-based central processing unit (CPU) having suitable memory and suitable conditioning electronics, drivers, and software for operating the various automated apparatus components. The computer 143 can control the operation of the quality check apparatus 100 as well as the characterization, processing, illumination, and imaging described herein.

[0067] The pre-screening of the sample 212 also allows for accurate quantification of the relative amounts of the serum or plasma portion 212SP and / or the settled blood portion 212SB, and / or the ratio between them. In addition, the pre-screening can determine the physical vertical position of the TC, LA, SB, SG, and / or BG and / or the bottom-most portion of the sample container 102. The quantification ensures that the sample 212 can be stopped from advancing to one or more analyzers if there is not a sufficient amount of the serum or plasma portion 212SP available for performing the tests that have been ordered thereon. In this way, inaccurate test results can be avoided via avoidance of possible aspiration of air. The ability to accurately quantify the physical position of the LA and SB or SG can not only minimize the possibility of aspiration of air, but also minimize the possibility of aspiration of the settled blood portion 212SB or the gel separator 313, if present. Thus, clogging and contamination of sample aspiration pipettes used to aspirate the serum or plasma portion 212SP for analyzers or at aliquoting stations can be avoided or minimized.

[0068] Reference is made to Figure 1 and 4A showing and describing a first embodiment of the quality check apparatus 100 that includes light sources 104A-104C embodied as a light panel assembly, which can include spectrally switchable light sources. The images obtained by the quality check apparatus 100 can allow for precise aspiration pipette positioning, determination of sufficient amounts (e.g., volumes or heights HSP) of the serum or plasma portion 212SP available for tests that have been ordered, and / or identification of, for example, H, I, and / or L or N (hereinafter HILN). Thus, use of the quality check module 100 can help avoid pipette clogging, aspiration of air by pipettes, and / or identification of unacceptable HIL levels, such that valuable analyzer resources are not wasted and confidence in test results can be improved.

[0069] Reference is now made to Figure 4AAn embodiment of a quality check apparatus 100 is shown. The quality check apparatus 100 can include imaging devices 106A-106C configured to capture digital images (i.e., pixelated images) at an imaging location 109 from multiple lateral viewpoints (e.g., viewpoints 1-3). The imaging devices 106A-106C can be any suitable type of digital imaging device, such as a digital camera, a charge-coupled device (CCD), a photodetector array, a CMOS sensor, etc. The imaging devices 106A-106C can be capable of taking digital images (pixelated images containing pixels) of any suitable image size in order to capture images of at least the serum or plasma portion 212SP, and in some embodiments, the settled blood portion 212SB and the cap 214. Other image sizes can also be used.

[0070] The imaging devices 106A-106C can be provided near the imaging location 109 and trained or focused to capture a view window at the imaging location 109 that includes the expected location of the sample container 102. In some embodiments, the sample container 102 can be placed or stopped at the imaging location 109, such as by stopping on the track 108, or by being placed at the imaging location 109 by a robot (not shown) so that it is approximately centered in the view window.

[0071] Referring again to Figure 1 and 4A The quality check apparatus 100 can include spectrally switchable light sources 104A-104D, as shown, provided by light panel assemblies to enable providing spectrally switchable illumination (back illumination, as desired). The spectrally switchable light sources 104A-104C can be spectrally switchable between at least two spectra, and in some embodiments, between 3 or more discrete spectra. The light sources 104A-104C can be constructed as described in, for example, U.S. Patent Publication 2018 / 0372648.

[0072] The light sources 104A-104D can provide switchable multi-spectral illumination. For example, in one embodiment shown in Figure 4A The light source 104A can be a light panel having an array of illumination elements 445. Figure 4A The other panels in Figure 4B may be constructed in the same manner as in Figure 4B and 7BAs shown in FIG. 4, the illumination elements 445 (LEDs) can be arranged along respective sides of the plate. Switching of the illumination elements 445 can be accomplished by software operable on a computer 143 coupled with appropriate power supplies and current drivers (744— Figure 7B Thus, by selecting only some of the illumination elements for illumination at a time, the light sources 104A-C can illuminate under a plurality of different spectra having different nominal wavelengths.

[0073] For example, the LEDs can include different color LEDs, such as red LEDs (R), green LEDs (G), and blue LEDs (B) that emit spectra at different nominal wavelengths. For example, the light panel assembly can emit red light at 634 nm + / - 35 nm, green light at 537 nm + / - 35 nm, and blue light at 455 nm + / - 35 nm. In particular, the light array can include clusters of R, G, and B LEDs that can be arranged in a repeating pattern along the height of the light array. Each LED of the same color can be illuminated simultaneously. For example, each red LED can be turned on simultaneously to provide red illumination from the light panel assembly to back illuminate the sample container 102 and sample 212 at the imaging location 109 during imaging thereof. Likewise, each green LED can be turned on simultaneously to provide green illumination of the imaging location 109 during imaging. Similarly, each blue LED can be turned on simultaneously to provide blue illumination at the imaging location 109 during imaging.

[0074] It should be recognized that R, G, and B are merely examples, and other wavelengths of light elements 445 can be used, such as white light elements (e.g., a wavelength range of about 400 nm to about 700 nm) that can be selected for certain types of background and / or foreground light imaging. In other embodiments, UV (a wavelength range of about 10 nm to about 400 nm), near infrared (NIR - a wavelength range of about 700 nm to about 1250 nm), or even infrared (IR - a wavelength range of about 1250 nm to about 2500 nm) can be included, and can be turned on at times for certain types of imaging. When multiple plates and viewpoints are used, the image of each respective color is taken separately with only the back illumination for that particular imaging device 106A-C illuminated.

[0075] Calibration method

[0076] Referring now to Figure 5A A schematic diagram of various imaging devices 106A-C and light sources 104A-C in the imaging equipment 101 of the quality inspection equipment 100 is shown. Also shown is a carrier 122 carrying sample tubes 102 (e.g., cuvettes) in a sample rack 120. Figure 1the centerline 108CL of the track 108 on which it travels.

[0077] Reference is also made to Figure 6 In the first stage, the calibration method 600 operates to locate an optical center position in the light sources 104A-104C of the imaging device 101, which optical center position can then be used to define a region of interest (ROI) within the imaging device 101 of the sample quality inspection device 100, which ROI can receive optimal illumination for back illumination and characterization of the sample tube 102 and the sample 212 contained therein. This can be done by first locating an optimal optical center 525 of the imaging device 101. This location can involve connecting the sensor optical center of each sensor 106SA-106SC of the imaging arrangement 106A-106C to each corresponding projection center 511A-511C of the respective light source 104A-104C. The projection center 511A-511C is a location resulting from a perpendicular projection from each sensor optical center to the respective light source 104A-104C. Thus, the projection center 511A-511C can deviate from the physical center of the respective light source 104A-104C, and especially for the light sources 104B, 104C. As shown in Figure 5A The optimal optical center 525 is located at the point closest to the intersection of the three lines 513A-513C. The mechanical center 535 is located at a position deviating from the optimal optical center 525, and is a position along the centerline 108CL of the track 108.

[0078] To locate the optimal optical center 525, we first detect the centerline (the physical vertical centerline) of each backlight 104A-104C. The physical center is shown in Figures 5B-5D The three light sources 104A-104C as observed by the directly facing imaging arrangement 106A-106C are shown in Figures 5B-5D Figures 5B-5D ​Images 537A-537C are illustrated that are from (taken by) respective imaging devices 106A-106C and show the orientation of the respective light source 104A-104C (light panel) therein, with respective imaging zones 538A-538C shown positioned within the images 537A-537C. The identified imaging zones 538A-538C are windows of arbitrary width, but are laterally centered on the center position (identified by crosshairs 541A-541C) of each image 537B and 537C. It can be seen that the light panel (illuminated area) is not centered on the images 537A-537C. Crosshairs 541A-541C are shown with a horizontal position at the center of the width of each respective image 538A-538C. The vertical position of crosshairs 541A-541C is shown approximately at the vertical center of the respective light source 104A-104C. Thus, in block 602, an imaging zone 538A-538C is identified with respect to each imaging device 106A-106C. The imaging zone 538A-538C can be wide enough to accommodate, for example, the expected width of a sample tube 102, and extend high and low enough on the zone to approximately cover the illuminated panel area of the light source 104A-104C approximately from top to bottom. If multiple sample tubes 102 of different widths are to be imaged, the imaging zone 538A-538C can be wide enough to accommodate the widest tube.

[0079] Next, in block 604, the center position 544A-544C of the non-occluded imaging zone 539A-539C of each light source 104A-104C is determined. For example, an LCD occlusion layer can be superimposed over each light source 104A-104C. This can be done by using an LCD occlusion layer 755 in front of each light source 104A-104C. The occluded portion of the LCD occlusion layer 755 is shown in Figure 7B' hatched lines. Given the light panel arrangement in one embodiment as shown in Figure 1 and 4A , where light source 104B and light source 104C are further from the mechanical center 535 of the imaging location 109 than light source 104A, light source 104B and light source 104C can be made larger than light source 104A in order to provide comparable illumination.

[0080] By masking out all light except the intended non-masked imaging area 539A-539C in front of the light sources 104A-104C (such as with the LCD mask 755), the center position 544A-544C of each light source 104A-104C can be optically located by positioning the boundary of the center segment within the search window 540A-540C. The horizontal size of the search window 540A-540C is determined by the lateral width of 104A-104C. The vertical size of the search window 540A-540C can be pre-determined empirically, such as by either using a fixed size (such as 100 pixels) or using 1 / 4 of the height of 538A-538C. The search window 540A-540C is vertically positioned at the vertical center of the respective light source 104B based on the lighted area it views from the respective image capture device 106A-106C.

[0081] As shown in FIG. 6, the method 600 first defines the search window 540A-540C (bounding box) according to the size (width) of the light source 104A-104C as seen in FIG. 5. Within the search window 540A-540C, the boundary of the imaging area 539A-539C can be easily located as shown in the vertical line extending vertically within the search window 540A-540C, and the exact center position within the imaging area in the search window 540A-540C of each light source 104A-104C, which is depicted as the cross line (X) 544A-544C, can be accordingly derived. Assuming the imaging devices 106A-106C in the imaging apparatus 101 have been calibrated, so we know the relative pose between any two imaging devices, we can use a triangulation algorithm to find the best optical center 525 in 3D space. Figures 5E-5G Figures 5B-5D As shown in FIG. 6, the method 600 first defines the search window 540A-540C (bounding box) according to the size (width) of the light source 104A-104C as seen in FIG. 5. Within the search window 540A-540C, the boundary of the imaging area 539A-539C can be easily located as shown in the vertical line extending vertically within the search window 540A-540C, and the exact center position within the imaging area in the search window 540A-540C of each light source 104A-104C, which is depicted as the cross line (X) 544A-544C, can be accordingly derived. Assuming the imaging devices 106A-106C in the imaging apparatus 101 have been calibrated, so we know the relative pose between any two imaging devices, we can use a triangulation algorithm to find the best optical center 525 in 3D space.

[0082] Thus, in block 606, the best optical center 525 of the imaging apparatus 101 is determined using the center position 544A-544C of the LCD mask of each imaging device 104A-104C and the center of the sensor 106SA-106SC. Alternatively, for a setup without using the LCD mask layer, the best optical center 525 can be determined directly from the center position 541A-541C of the imaging area 538A-538C. The lighting panel area and the image center together determine the imaging area 538A-538C, and thus the center position 541A-541C of the imaging area 538A-538C. Then, a triangulation algorithm can be applied to derive the best optical center 525 in 3D space.

[0083] Mechanical center positioning

[0084] ​While the optimal optical center 525 is the preferred position for placing the sample tube 102 for back illumination, due to mechanical limitations, it can not be physically feasible to place the sample tube 102 at that point. Therefore, the goal of the mechanical center positioning is to find a position in the space along the track 108 where the sample tube 102 can be placed that is closest to the optimal optical center 525. To do this, the method can use a tube calibration tool 450 installed in the carrier 122 Figures 4C-4D . The tube calibration tool 450 can include a tubular member that can be housed in a socket 422R in the carrier 122 in the mechanical position shown Figure 4C . The socket 422R in the carrier 122 can be formed by a support 422S. More or fewer supports can be used. Thus, in block 608, the tube calibration tool 450 is installed in the carrier 122 that resides on the track 108.

[0085] The tube calibration tool 450 is placed in the carrier 122, which is moved along the track 108 by any suitable method, and the position of the center point 442 (the physical 3D center on the centerline of the tube 102 for its characterization) is calibrated precisely according to the method 600. The tube calibration tool 450 can reside in the socket 422R of the carrier 122, which is similar to the carrier shown in U.S. Patent Publication 2018 / 0372648. Other suitable carriers can be used. The tube calibration tool 450 can include a step 426 as shown in Figure 4D . This step 426 and smaller dimension portion 427 can be used to locate the center point 442 of the tube calibration tool 450 relative to the image as shown in Figures 5H-5J . The center points 542A-542C for each view 1, 2, 3 are the intersection of the plane of the step 426 and the lateral centerline of the smaller dimension portion 427 relative to the image as shown in

[0086] By detecting the tool center 542A-542C from each view 1, 2, 3 in each image 504A'-504B' via a center finding routine as shown in Figures 5H-5J , the tool center point 542A-542C can be located and a triangulation algorithm can be utilized to determine the 3D center point 442 of the tool. The method 600 then compares the current mechanical center position to the optimal optical center 525 and adjusts the position of the carrier 122 along the track 108 until the center point 542A-542C of the tube calibration tool 450 reaches a position that is closest to the optimal optical center 525. This can require several iterations. The center point 542A-542C of the tube calibration tool 450 at this final position will be considered the mechanical center 535.

[0087] Once we have identified the mechanical center 535, we can back project this mechanical center from each imaging device 104A-104C to its corresponding backlight 104A-104C to find the light center directly behind the sample tube 102 and accordingly define a region of interest (ROI) 747 having a fixed size area when we place the sample tube 102 at the mechanical center 535.

[0088] Thus, in block 610, the carrier 122 is moved on the track 108 so that the center of the tube calibration tool 450 (e.g., the center of the smaller dimension portion 427) is located at a position closest to the optimal optical center 525 of the imaging device 101, which is expressed by the rectangular box centered at the optimal optical center 525 shown in FIG. 6B. Figures 5H-5J Thus, the center point 442 of the tube calibration tool 450 is used to determine the center position of a region of interest (ROI) 747 (e.g., the center of the smaller dimension portion 427) that is used for backlight calibration in each of the viewpoints 1-3 of each imaging device 106A-106C. Thus, in block 616, the region of interest (ROI) 747 (e.g., the center of the smaller dimension portion 427) for backlight calibration is determined. Figure 7B Figure 7B The ROI 747 can be selected to have a size that is associated with the region that is to be characterized in the sample tube 102 or the specimen 212. For example, the ROI 747 can be selected to have the size of the expected serum or plasma portion 212SP, or slightly larger. Once the region of interest ROI 747 is selected, the ROI 747 can be calibrated in block 716. The above process can be repeated for all viewpoints 1-3 in block 616. One suitable calibration method 700 for calibrating the region of interest (ROI) in the light panel 104A-104C identified in the method 600 is described below.

[0089] Adjusting

[0090] For the targeted application of the device (e.g., the imaging device 101 of the quality check module 100), it is desirable that the panel illumination is uniform / even at a predetermined illumination intensity. The illumination intensity of the panel is mainly dependent on the electrical drive current used to drive the respective LEDs that can be included in the LED strip. This drive current is known, but there are several unknown factors that also affect the intensity, such as:

[0091] - individual LED efficiency (radiant flux vs. current);

[0092] - light coupling losses of the LED vs. light guide, such as mechanical tolerances and surface quality;

[0093] ​- Tolerances in the composition of the light guiding material.

[0094] Due to these unknown factors, it is not possible to simply reproduce the electrical drive current to achieve a reproducible illumination intensity; instead, it is calibrated as described in the following calibration method 700 below with reference to Fig. 7.

[0095] The illumination uniformity in a region of interest (ROI) 747 of a light source (e.g., light source 104A, 104B, 104C) mainly depends on the illumination power distribution over the plurality of light elements 445 (e.g., which can be arranged as LED strips, see Fig. 6) on the respective side (e.g., first lateral side 746 and second lateral side 748) of the respective light source 104A-104C. Since the ROI 747 and thus the distance to the plurality of light elements 445 (e.g., light strips) can vary depending on the mechanical center position calibration discussed above, the present calibration method 700 operates to adjust the drive current to the respective plurality of light elements 445 for those light panels (e.g., light sources 104A, 104B, 104C) in two stages while observing the respective light source 104A, 104B, 104C with the opposing imaging device 106A, 106B, 106C. Figure 4B and 7B

[0096] According to the method 700, in block 702, first the plurality of light elements 445 (e.g., which can be arranged as LED strips) located on a first side (e.g., first lateral side 746) such as closer to the ROI 747 are turned on.

[0097] In block 704, the drive current Csi to the light elements 445 (e.g., LEDs) of the first side 746 is then adjusted until the representative intensity Ir (e.g., first average intensity) at the ROI 747 reaches a first preset intensity value Ip1 (e.g., 100 digits in that digital image in the range of 0 to 256 digit gray levels). Next, the method 700 essentially keeps the drive current Csi in line 450R to the light elements 445 of the first side 746 at that preset intensity value Ip, and in block 706, the drive current Cs2 in line 450L to the light elements 445 (e.g., LEDs, which can be arranged as strips or arrays) on the second side 748 is adjusted until the representative intensity (e.g., average intensity) at the ROI 747 reaches a second preset intensity value (e.g., 180 digits in that digital image in the range of 0 to 256 gray levels).

[0098] ​In the first calibration of multiple light elements (LED strips) closer to the ROI 747 (see bounding box), a pixelated image (photo) of an example of light element (LED) adjustment is shown until the average intensity reaches a first preset intensity level (e.g., 100 bits in the range of 0 to 256 gray scale range), and then, as shown in Figure 7D

[0099] For a panel where the ROI center is located at almost equal distance from both sides (e.g., light source 104A), we set the same current to both sides 746, 748 of the light elements 445 (LEDs) and adjust them until the average intensity of the ROI 747 reaches a final preset value (e.g., 180 bits in the range of 0 to 256 in this image). To speed up the current adjustment process, two or more preselected current settings can be saved in memory and then the corresponding intensities can be measured. With these values, the method 700 can utilize a first or second order equation to approximate the current intensity curve for predicting what current can be applied in order to generate a target intensity. Thus, the final target intensity of the ROI 747 can typically be reached within a few iterations. This calibration method 700 can be performed for each wavelength of interest, such as, for example, R, G, B, W, UV, IR, and / or NIR for each light source 104A-104C.

[0100] Health Check

[0101] When we use the center ROI 747 for calibrating the light elements 445 (e.g., LED strips), it can be desirable to verify the light distribution across the light source or a representative portion thereof (e.g., light sources 104A, 104B, 104C) to prevent or minimize inconsistent illumination within and across multiple sample quality inspection apparatuses 100. Based on the location of the center ROI 747 relative to the area of the entire light panel 104A-104C, multiple off-center regions can be selected and then the representative intensity (e.g., average intensity) of the off-center regions (areas) can be compared to the average intensity of the center ROI 747. The areas of these regions can be of any size, but in some embodiments can be the same size as the center ROI 747.

[0102] Figure 8 ​An example pixelated image showing these regions (dotted boxes and dash-dotted boxes), as well as the average intensity of other regions of the plate compared to the central ROI (solid box) corresponding to the location of the central ROI 747, is shown, with the average intensity represented by a percentage. By establishing a nominal intensity value for each region using a reference sample quality check system or using statistical information from multiple good sample quality check systems, the consistency of any light plate can then be verified. This can be used to perform an LED health check, which can be performed periodically or at any desired interval.

[0103] A calibration method 600 for calibrating the imaging device 101 will now be described. The calibration method 600 includes imaging that ideally occurs prior to the imaging device 101 of the quality check module 100 actually taking pre-screening imaging measurements. Thus, the calibration method 600 can be used for more than one pre-screening operation (e.g., pre-screening of multiple sample tubes 102) before re-calibration is performed again. The calibration method 600 can be performed prior to pre-screening of any sample tube 102 for the presence of interferents (such as for HILN), artifacts (such as clots, foam, or air bubbles), and the like. In some embodiments, a single calibration method 600 can be performed for a particular rack of sample tubes 102, for a large number of sample tubes 102, for a time period such as a shift, a day, a week, or a month, or other time period after a certain number of sample tubes 102 are pre-screened, or any other suitable calibration period or interval. Thus, the calibration method can be performed after pre-screening of multiple sample tubes or after a particular time period after pre-screening is initiated.

[0104] While the application is susceptible to various modifications and alternative forms, specific systems, devices and methods thereof have been shown by way of example in the drawings and are described in detail herein. However, it should be understood that it is not intended to limit the disclosure to the particular systems, devices or methods disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the claims.

Claims

1. A calibration method, comprising: For each imaging device, the imaging area on each light plate is identified; Determine the center position of the imaging area for each light plate of each imaging device; The optimal optical center of the imaging device is determined using the center position of each light plate for each imaging device; The tube calibration tool is mounted in a carrier on the track; The carrier is moved on the track such that the center of the tube calibration tool is located at the position closest to the optimal optical center of the imaging device; Determine the mechanical center as the center of the tube calibration tool at the nearest location; and The mechanical center is used to determine the center of the region of interest for backlight calibration for each light plate.

2. The calibration method according to claim 1, wherein the center position is determined laterally by the image center and longitudinally by half the height of the illumination area of ​​the light plate.

3. The calibration method according to claim 1, wherein the center position is determined by the center of the masking layer on each light plate.

4. The calibration method according to claim 1, further comprising: Perform background calibration on the region of interest.

5. The calibration method according to claim 4, comprising: A first driving current is activated to drive multiple optical elements on a light plate adjacent to the region of interest. Adjust the first driving current of multiple optical elements going to the light plate on the first side until the representative intensity at the region of interest reaches a preset value; as well as While the driving current is still being driven to multiple optical elements on the light plate on the first side, the driving current to multiple optical elements on the light plate on the second side is adjusted until the representative intensity of the region of interest reaches a second preset intensity value.

6. The calibration method according to claim 5, further comprising: First, a first driving current is activated for multiple optical elements on the first side of the light plate closest to the region of interest.

7. The calibration method according to claim 1, further comprising: The average intensity of at least one other region of the light plate is compared with the average intensity of a second preset intensity value of the region of interest.

8. The calibration method of claim 7, wherein comparing average intensities comprises: Displays the percentage of the average intensity value of each of the at least one other region to the average intensity of the second preset intensity value.

9. The calibration method according to claim 1, comprising: The average intensity of another area of ​​the plate is compared with the average intensity value of a comparable area from a reference sample quality inspection system.

10. The calibration method of claim 1, wherein the calibration method is performed before pre-screening the sample tubes for interfering substances.

11. The calibration method according to claim 1, wherein the calibration method is performed after pre-screening of multiple sample tubes or after a specific time period following the initiation of pre-screening.

12. The calibration method of claim 1, wherein the center position of each light source is optically located by locating the boundary of a central segment within a corresponding search window, wherein the central segment is based on the intersection of the search window and the unmasked area.

13. The calibration method according to claim 1, wherein the plurality of optical elements includes a red light element, a green light element, and a blue light element.

14. The calibration method according to claim 13, wherein the plurality of optical elements includes white light elements.

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