GB2579550A

GB2579550A - Sample loading device

Info

Publication number: GB2579550A
Application number: GB1819588.3A
Authority: GB
Inventors: Fautz Michael; Kulliq Konrad
Original assignee: Stratec Biomedical AG
Current assignee: Stratec Biomedical AG
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2020-07-01
Also published as: GB201819588D0

Abstract

A device for loading samples to an automated analyser system and providing a method for reading barcodes in an automated analyser system, comprising the steps of capturing images of at least two position codes applied to a rack for carrying sample container; detecting the at least two position codes in every image; selecting a single image for barcode reading for reducing the number of images for reading in barcodes; and reading a barcode in a sub-region of the selected image. The position codes may be 2D barcodes. The method may be used to determine rack movement, insertion speed of the sample carrier, empty sample positions or features of the sample container.

Description

SAMPLE LOADING DEVICE

DESCRIPTION

Field of the Invention

[0001] The invention relates to a device for loading samples to an automated analyser system.

Brief description of the related art

[0002] Automated analyzer systems for use in clinical diagnostics and life sciences are produced by a number of companies. For example, the STRATEC' Biomedical AG, Birkenfeld, Germany, produces a number of devices for specimen handling and detection for use in automated analyzer systems and other laboratory instrumentation.

[0003] Automated analyzer systems typically have or are connected to devices or a member for loading of e.g. patient samples and assay specific reagents. Loading is mostly done manually, meaning that the speed with which a target like a code is passing a means for identification like a scanner can widely vary. Typically, such devices are equipped with laser scanners that allow for barcode reading. Barcodes are the most widely used means of identification for patient samples at a doctor's practice, in laboratories, hospitals, clinical applications and blood banks.

[0004] 2D codes are becoming more and more popular in this context as they allow for a denser packaging of information in a smaller area. 2D codes are already common for reagent IDs and there is an upcoming demand to have 2D codes for patient sample identification on analyzer systems as well.

[0005] Laser scanners are commonly used for barcode scanning. They differ in a wide range of technical specifications and their price, reading speeds and the ability to focus at various distances or only providing a fix focus. Beyond the identification of samples on racks it is necessary to identify their exact position and the order of sample containers in a rack. For that reason, position barcodes are commonly used between the sample tube positions. As laser scanners are only able to read barcodes, empty codes are used to detect a missing sample tube. Such empty codes are placed behind a sample tube and they are only visible without a tube.

[0006] Merging the information of position and sample tube related data is simple if the rack movement continues in a single direction during an insertion sequence so that the scanner can report every new identified code to the system (comp. FIG. 1).

[0007] 2D code readers typically use cameras with a CCD or CMOS chip. They widely differ in technical aspects like resolution, detection range and speeds, the ability to focus and integrated illumination.

[0008] As camera-based readers have to scan the whole image for potentially present ID codes, the insertion speed of racks has to be reduced to ensure reliable reading.

[0009] Laser scanner-based systems known from the prior art are related to the disadvantage that laser scanners are only able to read 1D barcodes. Reading 2D codes or other features like the detection of a missing tube are not directly possible with such systems.

[0010] Camera based system known from the prior art are related to certain disadvantages, like reconstruction of a barcode sequence can be difficult or ambiguous if not all barcodes are identified. The maximum insertion speed has to be limited, because the whole picture has to be captured and analyzed. Capturing images in a memory for a later processing causes a response delay after insertion which can be irritating for a user. Finally, empty position detection is difficult by unknown and variable insertion speed or empty codes that have been used outside the camera focus.

Object of the Invention [0011] It is an object of the present invention to provide a system and a method for a secure and fast reading of barcodes.

Summary of the Invention

[0001] This problem is solved by the features and elements of the method and device as described in the independent claims, while meaningful embodiments are described by the features and elements of the dependent claims.

[0002] The present disclosure proposes a method for reading barcodes in an automated analyser system, comprising the steps of: a. Capturing images of at least two position codes applied to a rack for carrying sample container; b. Detecting the at least two position codes in every image; c. Selecting a single image for barcode reading for reducing the number of images for reading in barcodes; and d. Reading a barcode in a sub-region of the selected image.

[0012] In a further aspect of the invention, the position codes can be 2D barcodes.

[0013] The method may further encompass that the detection of the at least two position codes is performed at the image capturing frame rate.

[0014] In is further envisaged that step b may further comprise determining the position Ms and their location in the image.

[0015] In a further aspect of the proposed method, in step c a pre-defined list of regions of interest may be used defining regions where a position code can be expected.

[0016] In a further embodiment of the method the pre-defined list of regions of interest may be based on a predefined or known rack geometry.

[0017] The method may further encompass that the location of the barcode is linked to the location of a position code.

[0018] A 1:1 relationship between the location of a position code and a barcode may further be intended.

[0019] It is further envisaged that in step d a region for barcode reading is calculated, the barcode is read, and the barcode is assigned to a position code.

[0020] The method may further comprise that position codes are arranged as a ruler.

[0021] In a further embodiment in step c the image data can be reduced by the selection of a single image.

[0022] It is further intended that steps a to d are performed in real time.

[0023] Another object of the invention refers to a use of a method as described above for determining rack movement, insertion speed of sample container, empty sample positions or features of a sample container.

[0024] The invention refers further to a system for detecting a barcode comprising position codes and barcodes with information relating to a sample container, a rack for carrying both types of codes, a camera system and a data processing unit for performing the method as described above [0025] Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating preferable embodiments and implementations. The present invention is also capable of other and different embodiments and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description or may be learned by practice of the invention.

Summary of the Figures

[0026] For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description and the accompanying drawings, it shows: FIG. 1 Rack with indicated region for position codes FIG. 2 Schematic representation of a generalized approach FIG. 2 Schematic depiction of specialised approach FIG. 3 Relationship between 2D position code location and barcode Detailed Description of the Invention and the Figures [0027] The technical problem is solved by the independent claims. The dependent claims cover further specific embodiments of the invention.

[0028] A sample within the meaning of the instant disclosure may be liquid, solid, gaseous or a mixture thereof The sample may comprise body fluids or parts thereof A sample may further comprise buffer, solutions or reagents for performing a chemical reaction requiring specific conditions.

[0029] The term sample container comprises any receptacle suitable for carrying a sample, including bottles, tubes.

[0030] An automated analyzer system comprises system suitable for automatically performing chemical, diagnostic or detection reactions. Thus, any bio-medical or bio-chemical analyzer is an automated analyzer according to the invention.

[0031] A barcode within the meaning of the present invention shall be understood as an an optical, machine-readable, representation of data. The data of the present invention may be related to a position (position code) or properties of a sample container or its content, respectively. Codes may be chosen from the group comprising but not limited to one dimensional codes such as bar codes and two dimensional codes as for example QR codes, aztec codes and data matrices [0032] The present invention relates to a device or member of an automated analyzer system in which patient samples and assay reagents and potentially other consumables have to be loaded (manually or automated) and identified. Said device provides means for reading information that is located on sample or reagent carriers like sample IDs, types of reagents, types of consumables, expiration dates, number of tests to be performed out of carriers etc. [0033] The invention relates in particular to a camera-based method for an efficient, secure and fast reading of ID codes like barcodes or 2D codes in these devices.

[0034] The invention provides a solution for a fast and secure reading of 1 D and 2D barcodes on sample tubes placed into a manually inserted rack. The main tasks to be solved by the present invention ca be summarized as follows: a. High speed barcode reading The insertion of a rack containing 12-16 samples is typically performed within one to two seconds. For usability reasons the response time of such a system is expected to be below 300 milliseconds after the rack insertion is completed.

b. Security of exchange The system guarantees that the sequence of identified barcodes matches the sequence of sample tubes placed into the rack. This may sound to be a simple task, but in fact it turns out to be very difficult to solve this in an erroneous environment, where the direction of movement is unknown and may change during the insertion and it has to be assumed that some barcodes in the images exist but were not identified. Under working conditions where only a few numbers of barcodes are depicted in one image this may lead to the problem that the correctness of the barcode sequence cannot be guaranteed.

[0035] The present invention solves these issues by using a novel approach, placing additional 2D position codes as a ruler onto the rack. Placing the position code on the rack comprises all common technologies like, printing, use of adhesive labels, laser marking, etc. These position codes allow measuring the rack position during insertion for every image. As this measurement needs to be done for even* image, a highly optimized detection algorithm for the 2D position codes is used. A special processing sequence is used in order to reduce image processing effort which is the key for obtaining real-time capabilities in combination with requiring low processing power. The known rack geometry is used as additional a-priori information. This knowledge of the position, where barcodes can be expected, is then used to reduce the high number of images that are acquired during the insertion procedure to obtain one "best image" per sample position. In the next step, only the sub-region of the image where a sample can be placed is selected for barcode identification, which improves barcode identification speed significantly.

[0036] The benefits of such a system are that the use of 2D position codes as a ruler for position measurement of the inserted rack allows secure assignment of the barcodes to their matching sample tubes and the simple realization of additional features like measuring the insertion speed between two images, localization and detection of other rack or tube features that can be referenced relative to the 2D position code. The processing sequence further allows for image processing in real-time while requiring low processing power.

[0037] FIG. 1 shows a rack 4 with a places for position codes 1. Position codes 1 also can be placed on top of a rack depending on the respective rack geometry.

[0038] A rack 4 that has a predefined place where the position codes 1 can be placed is used (comp. FIG. 1), wherein this place can be either located on the bottom or top of the rack. It is important that the place for position codes 1 is defined to be a small part of the camera field of view to reduce the area where position codes have to be searched in order to speed up the recognition process.

[0039] The speed of the 2D position code detection is essential for the overall system performance as the 2D position codes need to be captured in every image at a high frame rate in a camera filed of view 10. Thus, a special, non-standardized matrix code is used. The image features of this code are designed in a way that allows for very fast detection of the label and fail-safe interpretation of its code. A small matrix for the code (5x5 in for instance) is used and a larger module size for a fast detection along with error correction capabilities (e.g. hamming code). A special arrangement of the code bits in the matrix is used to improve robustness against typical code defects (e.g. local or linear defects). The bits belonging to one code word are distributed in the matrix such that a typical defect only causes a partial cancellation of the information which can be corrected by the error correction capabilities of the code.

[0040] The use of 2D position codes allows deriving two types of information that guide and speed-up the rack reading process: 1. The position within the rack / the image, which can be used to localize a related image region for analysis; 2. The information encoded in the matrix code. The data encoded in the 2D position codes contains information (a-priori knowledge) that can be used to control the reading process and provides additional information on the rack: - As a ruler, the position codes may encode a number used for measuring the absolute position of the rack while it is inserted (see generalized approach below).

- The tube (barcode) number on the rack. This is an essential information used for safe assignment of a read barcode to a tube position (see specialized approach).

[0041] The full capacity of the 2D code is not needed for enumeration of the position codes, so that remaining parts may be used to distinguish: - different rack types or rack layouts (additional information encoded in first position code), - or different types of positions (e.g. sample tube, reagent vial, rack number, etc.) with different ROIs for barcode reading.

[0042] The arrangement of the 2D position codes on the rack can be done in different ways: 1. One position code for each barcode.

A simple strategy for reliable barcode reading is to use a 1:1 mapping of position codes and barcodes. Obviously, not every image needs to depict a position code as well as position codes do not need to be arranged equidistantly.

2. One position code visible per image.

If the distance between the 2D position codes is chosen to guarantee that in every image at least one position code is contained, then in addition to (1), continuous measurement of insertion speed is possible (in image coordinates).

3. Two position codes visible per image.

In this case, a normalized coordinate system can be used for measuring any position visible in any of the acquired images. So besides continuous measurement of the insertion position (in normalized coordinates), this position code arrangement also allows arbitrary positions of the barcodes on the rack [0043] The application of the different options for 2D position codes leads to the following main strategies for barcode reading according to the present invention: 1. Generalized approach, allowing flexible barcode arrangement.

2. Specialized approach. Here the ROI where barcodes are searched are derived from the location of a position code.

[0044] The generalized approach encompasses that the 2D position codes are used as a kind of ruler providing absolute position measurement of the inserted rack in every image. The generalized approach further requires either to have a field of view that depicts two position codes in each image or the pixel distance between two 2D position codes is already known. With this additional information any position on the rack can be defined using normalized coordinates where the integral coordinate values are encoded in the 2D position code and positions in between are interpolated (comp. FIG. 2). The layout of all barcodes on a rack builds the a-priori knowledge for a specific rack type that will be used for an optimized reading process.

[0045] FIG. 2 shows that the generalized approach allows for a flexible arrangement of barcodes on a rack. Information on the barcode layout is predefined as a-priori knowledge that is used for an optimized barcode reading process.

[0046] During processing according to the present invention, three main processing steps will be executed that are required for the performance and reliability of the system.

Step The 2D position codes I are detected in every image. This algorithm is highly optimized as it needs to be executed for every image at the image capturing frame rate. Results are the position ID's and their location in the image.

Step 2: In this step the main data reduction is performed. The location of the position codes is used to select the best image for barcode reading. Rack specific a-priori knowledge is used for the selection, e.g. start positions 14 and end positions 13. In the generalized approach this is the list of regions of interest (ROIs) where barcodes are expected.

Step 3: Barcode reading is executed for a sub-region within the selected image. Due to the step 2, barcode reading for each expected barcode is only triggered once. An additional speedup is achieved as barcode reading can be restricted to a region within this image where the barcode is expected. Both properties of the proposed algorithm, the reduction of the number of images barcodes are read in, and the subregion are the key advantages that can be achieved by the use of the proposed 2D position codes. They allow that the invented system can perform real-time barcode reading on racks with low computing power requirements.

[0047] As shown in an embodiment in FIG. 3, the first step of the processing sequence serves for detecting the 2D position codes I in every image. The highlighted 2D position code 15 has a 1:1 relationship to the sample tube above the position code. The system selects the image that depicts the region where the sample barcode is expected in the image center while capturing the image sequence.

[0048] In the third step (comp. FIG. 4) the a-priori knowledge of the rack geometry is used again to clip the image, trigger barcode reading and assign the result to the tube position on the rack Therefore, the described novel solution reduces the general task of reading all barcodes in all images to reading of one barcode in a part of one image for every known sample position. The system is furthermore very robust and even detection errors cannot lead to the assignment of a read barcode to a false position.

[0049] The obtained processing speed and security, that can be achieved due to the use of 2D position codes, have been proven to be the key features for real-time barcode reading of manually inserted racks.

[0050] The main idea of the invented system is the application of 2D position codes and their special arrangement as a 'ruler'. One feature of the system is the design of the 2D position codes for efficient real-time reading. This serves as a basis for the second feature: achievement of major data reduction by bringing down the task to read all barcodes in all acquired images to read each barcode for each expected sample tube only once by preselecting the images. This reduces the image processing effort down to a level that allows real-time barcode reading at low performance requirements and therefore low system costs.

[0051] None of the known systems in the prior art provide such capabilities. They usually need expensive processing hardware, low rack insertion speeds and still have longer response times compared to the proposed system.

[0052] The second main advantage of the system according to the invention is the use of 2D position codes is the secure assignment of a read barcode to its position on the rack. In the presently described system no mix-up can occur by design. This is guaranteed because the position code is visible in the same image as the read barcode.

[0053] Besides the main advantages the invention has the following additional advantages with respect to methods known in the prior art: Direction of rack movement can be determined: Conventional systems use laser-scanners and additional separating barcodes are placed between sample tube positions. The direction of movement can only be calculated if the rack is moved at least for a distance corresponding to the distance between two separating barcodes. A possible general approach for camera-based systems is to calculate an optical flow, which is computational expensive.

The approach of the present invention is based on 2D position codes that are ordered. The movement of the rack can be calculated easily becuase their position is detected in every image. As a consequence, the system of the present invention is also able to detect 'un-allowed' movements (e.g. sawing) more precisely.

Insertion speed can be determined: All barcode scanning systems have limitations with respect to the maximum allowed insertion speed of a rack in common. With conventional systems, the only response a user gets is that no barcode is detected for some positions. The user does not get the information if the problem occurred due to a too high insertion speed or may be related to the barcode label (e.g. positioning of tube, barcode quality, etc.).

A system according to the present invention is able to measure the insertion speed continuously and provide the detailed reason of reading failure to the user, e.g. requesting a re-insertion if speed was too high for some barcode positions or presenting the images of the unread tubes otherwise.

Detection of empty positions: Laser scanning systems often use the approach of having an empty barcode ID placed behind each position. A similar approach also is needed for camera-based solutions that cannot calculate the rack position from the image.

The system of the present invention is able to identify regions where barcodes are expected without the need for additional empty barcodes.

2D position codes support detection of additional features: The system of the present invention is able to localize the expected position of a sample tube in an image. This allows for detection of additional features related to the sample tube with the same efficiency as used for barcode reading as the feature only needs to be detected in a sub-region of a single image. Such features can be cap detection as well as measuring tube diameter.

[0054] The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. The entirety of each of the aforementioned documents is incorporated by reference herein.

Reference Numerals 1 position code 3 sample tube 4 rack sample tube code

camera field of view

13 position end 14 position start

Claims

CLAIMSA method for reading barcodes in an automated analyser system, comprising the steps of: a. Capturing images of at least two position codes applied to a rack for carrying sample container; b. Detecting the at least two position codes in every image; c. Selecting a single image for barcode reading for reducing the number of images for reading in barcodes; and d. Reading a barcode in a sub-region of the selected image.
The method of claim 1, wherein the position codes are 2D barcodes.
3. The method of claim 1 or 2, wherein the detection of the at least two position codes is performed at the image capturing frame rate.
The method of any one of claims 1 to 3, wherein step b further comprises determining the position IDs and their location in the image.
The method of any one of claims 1 to 4, wherein in step c a pre-defined list of regions of interest is used defining regions where a position code can be expected.
The method of claim 5, wherein the pre-defined list of regions of interest s based on a rack geometry.
The method of any one of claims 1 to 6, wherein the location of the barcode is linked to the location of a position code.
The method of any of claims 1 to 7, with a 1:1 relationship between the location of a position code and a barcode.
The method of any of claims 1 to 8, wherein in step d a region for barcode reading is calculated, the barcode is read, and the barcode is assigned to a position code.
10. The method of any one of claims 1 to 9, wherein position codes are arranged as a ruler.
11. The method of any one of claims 1 to 10, wherein in step c the image data is reduced by the selection of a single image.
12. The method of any one of claims I to 11, wherein steps a to d are performed in real time.
13. A use of a method according to any one of claims 1 to 12 for determining rack movement, insertion speed of sample container, empty sample positions or features of a sample container.
14. A system for detecting a barcode comprising position codes and barcodes with information relating to a sample container, a rack for carrying both types of codes, a camera system and a data processing unit for performing the method of any one of claims 1 to 12.