CH706779B1 - Method for code detection by means of a sensor arrangement - Google Patents

Abstract

The inventive sensor arrangement for code detection with an optical sensor (1) comprises an area camera (7) with a matrix-like arrangement of pixels (7a) and an evaluation unit (9) in which output signals of the pixels (7a) of the area camera ( 7) are evaluated. With the optical sensor codes are detected on a sample carrier during an insertion process, wherein the sample carrier has recordings for sample tubes. As the first codes on the sample carrier positions of the respective record identifying position codes are provided. As the second codes on the sample tube, there are provided bar code samples (6) containing samples which are arranged in a predetermined position relative to the assigned position code such that they can be detected by the optical sensor with image acquisition. During the insertion process, an image captured by the optical sensor (1) is evaluated only for the presence of the position code. Upon detection of the position code, the image with the determined position code is stored as an index. After completion of the insertion process, the evaluation of the stored images takes place in such a way that the barcodes (6) in the evaluation unit (9) are decoded and assigned to the respective position codes on the basis of the indices.

Description

Description [0001] The invention relates to a method for code detection by means of a sensor arrangement.

Such sensor arrangements are used in particular in the field of analysis automation. There, samples, in particular blood or urine samples, must be unambiguously and fail-safe identified when they are introduced into an automated analyzer in order to carry out specific investigations there with the samples. The samples are filled into individual sample tubes. The sample tubes carry the barcodes identifying the samples, which must be detected as first codes by the optical sensor. Several sample tubes are stored on a sample rack, which is then inserted into the automated analyzer. The sample carrier has individual recordings, in each of which a sample tube can be stored. To mark the recordings, second codes in the form of position codes are attached to the wall elements of the sample carrier bounding the receptacles on the side. These position codes must also be detected by the optical sensor in order to identify the spatial arrangement of the sample tube.

A major difficulty with known such systems is to assign the respective position codes correctly and correctly to the respective barcodes.

A major source of error is that in known systems, the position codes on the sample carrier and the bar codes on the sample tube are all read one after the other. From the chronological sequence of the individually read codes and barcodes, the barcode of a sample tube must then be assigned to the associated code on the sample carrier.

The invention has for its object to provide a method by means of which a fast and reliable code detection is possible.

This object is achieved by the features of claim 1. Advantageous embodiments and expedient developments of the invention are described in the dependent claims.

The invention relates to a method for code detection by means of a sensor arrangement with an optical sensor. The optical sensor comprises an area camera with a matrix-like arrangement of pixels and an evaluation unit in which output signals of the pixels of the area camera are evaluated for the decoding of a code. With the optical sensor codes are detected on a sample carrier during an insertion process, wherein the sample carrier has recordings for sample tubes. As first codes, positions of the respective recordings identifying position codes are provided on the sample carrier. As second codes are provided on the sample tube there samples containing characterizing barcodes which are arranged in a predetermined position relative to the associated position code so that they are detectable with an image pickup by the optical sensor. During the insertion process, an image captured by the optical sensor is evaluated only for the presence of the position code, and when the position code is detected, the image with the determined position code is stored as an index. After completion of the insertion process takes place for each recorded with an image recording barcodes and position codes, the evaluation of the stored images such that the bar codes are decoded in the evaluation and assigned to the respective position code based on the indices.

A first significant advantage of the invention is that during the insertion process with an image recording, that is, in a recorded image with the area camera image at the same time the position code and the associated barcode on the sample tube is detected. This type of image capture eliminates a significant source of error that results in bar code and position code misregistration, since it ensures that the barcode captured in an image with the location code also belongs to it. This is achieved in that the known, spatial assignment of the position code to the respective barcode is known and is taken into account in the image acquisition.

Another significant advantage of the invention is that during the insertion process, image acquisition and image evaluation in real time, even if the insertion processes are done quickly and possibly discontinuously. In accordance with the invention, this is made possible by the fact that the entire image content of an image taken with the area camera is not used in the image evaluation during the insertion process. Rather, in an image, only the image information concerning the position code is evaluated. Because of the typically simple contrast structure of the position code, it can preferably be decoded quickly in the evaluation unit of the optical sensor.

The thus-decoded position code then serves as an index, under which the entire recorded image is stored. This procedure is carried out in a corresponding manner for all images acquired during the insertion process.

After completion of the insertion process then there is an image sequence comprising a time-resolved sequence of images marked with indices, which includes the entire sample carrier during the entire insertion process.

All images are then, preferably in a computer unit, time-spanned after the insertion process, that is, in a larger time frame, evaluated. In this evaluation, the barcodes of the sample tubes are then decoded for the individual images and assigned to the position codes contained in the respective image. Through the identification

Drawing the individual images with the respective indices, these can be assigned immediately to the respective position codes. Since this position code and the bar code are contained in this image and are evaluated together with the image analysis of this image, misregistrations of these codes are systematically avoided.

By relocating currently consuming common evaluation of a position codes and barcodes within an image at a time after the insertion process, the single image capture during the insertion process can be done very quickly, since there only small part information of the respective images must be evaluated. Thus, a fail-safe detection of the bar codes and their assignment to the position codes is ensured with the sensor arrangement even with very quickly performed insertion operations.

Furthermore, with the sensor arrangement, a fail-safe detection and assignment of the individual position codes and barcodes is also achieved when an operator inserts the sample carrier discontinuously into the automatic analyzer, that is, the sample carrier does not push continuously in the direction of the automatic analyzer, but one or more times also slides the sample carrier in the opposite direction.

In this case, some position codes and bar codes are repeatedly detected by the area camera, that is, there are several images for this purpose. However, since all images are clearly indexed by the respective positional codes contained, it can not be misallocated even in such cases. Rather, in this case, even a multiple evaluation of multiple images for a position code, whereby the detection reliability in the code detection is further increased.

According to a first advantageous embodiment of the invention, the position codes form an arrangement of separate codes, wherein in each case a position code is arranged in a defined position relative to the associated receptacle for a sample tube and wherein in particular the position code is arranged laterally to the associated receptacle.

Such arrangements of position codes on sample carriers are widely used in the field of blood analysis. With the optical sensor according to the invention, such position codes and the barcodes associated therewith can be reliably recognized on the sample tubes without having to make specific changes to the sample carriers for this purpose.

According to a second advantageous embodiment of the invention, the position codes are components of a Positionsmassstab forming belt, each position code is arranged in a defined position relative to the associated receptacle for a sample tube and wherein in particular the position code is disposed below the associated receptacle.

In this embodiment eliminates a significant source of error that can lead to misallocation of samples, since a single attachment of position codes can be avoided on a rack. Rather, all position codes for a rack on a belt in predetermined target positions are arranged to each other. The tape can then be fixed to the rack in one operation so that all the rack's images are correctly marked with the correct location codes. The term band generally encompasses films, plastic strips, metallic strips and the like. The position codes themselves advantageously consist of two-dimensional codes which are printed, for example, on the tape.

For detecting the position codes during the insertion operation, a position code is advantageously recorded in a predetermined image area of the area camera.

In this case, the fact is exploited that with a defined arrangement of the optical sensor relative to the sample carrier, the position codes always appear in the same portion of the field of view of the area camera. Since therefore only a section of an image of the area camera must always be evaluated for the detection of a position code, the required computing time for image evaluation compared to a complete image analysis is significantly reduced.

In the evaluation of the images stored under the indexes after completion of the insertion process, in principle, the entire image can be evaluated in each case in order to detect the barcode associated therewith in addition to the position code.

This is particularly advantageous if, in addition to the barcode, further features of the sample tubes are also detected in the image evaluation, as a result of which the functionality of the sensor arrangement according to the invention is increased even further. Examples of such additional features are geometric data such as the height or diameter of a sample tube. Furthermore, it can be checked whether a sample tube is closed with a stopper or not.

[0024] According to a further advantageous embodiment of the invention, the bar code associated with the position code is only searched for within an image section of an image of the area camera after completion of the insertion process, the position and size of the image section through the image area of the Position codes is determined.

Thus, the computational effort for the detection of barcodes can be further reduced. Furthermore, error sources in the detection of the bar codes and their assignment to the correct position code can be excluded by a suitable dimensioning of the image section. A possible source of error is due to the curvature of typi cally hollow cylindrical sample tube. At the optical line facing the apex line of a sample tube directional light reflections can occur, leading to an overdrive of the surface camera. Therefore, instead of the one barcode to be read, two subsegments of the barcode separated by this light reflection appear on the area camera. In order to avoid that these are detected as two separate barcodes and possibly assigned wrong position codes, the image section can be selected so that only one of the segments of the bar code is evaluated.

The invention will be explained below with reference to the drawings. Show it:

Fig. 1: embodiment of an optical sensor.

Fig. 2: Schematic representation of a sensor arrangement.

Fig. 3: First embodiment of a sample carrier for receiving sample tubes.

Fig. 4: Second embodiment of a sample carrier for receiving sample tubes.

5 shows a partial representation of the arrangement according to FIG. 4 with a sample tube mounted in a receptacle of the sample carrier.

Fig. 1 shows schematically the structure of an embodiment of the optical sensor 1. The components of the optical sensor 1 are integrated in a housing 2. The optical sensor 1 is a stationary code reader, that is, the housing 2 of the optical sensor 1 is stored stationary to be able to detect codes in this position. The optical sensor 1 comprises a lighting unit 3, which preferably comprises an arrangement of light-emitting diodes. The light beams 4 emitted by the lighting unit 3 are guided through an exit window 5 in the front wall and serve to illuminate a detection area E, in which codes can be detected. The codes may generally be formed as one-dimensional or two-dimensional codes. 1 shows an exemplary embodiment of a one-dimensional code in the form of a barcode 6.

On the barcode 6 incident light beams 4 are reflected back from this and pass through the exit window 5 of the housing 2 on a receiver unit of the optical sensor 1. The receiver unit comprises a surface camera 7 with a matrix-like arrangement of pixels 7a, that is, photosensitive receiving elements. Preferably, the area camera 7 is formed in the form of a CMOS array or CCD array.

The area camera 7 is preceded by an optical element 8. With this optical element 8, an image of the light beams 4 on the area camera 7 takes place.

The illumination unit 3 and the area camera 7 are connected to an evaluation unit 9, which is formed by a microprocessor or the like. On the other hand, the evaluation unit 9 is used to evaluate the output signals of the individual pixels 7a of the area camera 7, that is, to evaluate the image information of a code captured by the area camera 7.

Due to the contrast structure of the code, which is formed in the present case of light and dark bar elements of the barcode 6, the light beams 4 impinging on the barcode 6 is impressed with a corresponding modulation, so that the light beams 4 on the area camera 7 a the barcode Provide 6 corresponding contrast image, provided that the barcode 6 is located within a certain depth of field range 10, within which the contrast pattern of the barcode 6 is sufficiently sharp imaged on the area camera 7.

In the evaluation unit 9, a decoding unit is implemented in the form of software modules, by means of which the barcode 6 or generally a code is decoded on the basis of the area recorded with the area camera 7, that is, the information contained in the bar pattern of the barcode 6 can be detected.

The optical sensor 1 is used in the field of automatic analyzers. There are in an automatic analyzer 11, which is shown schematically in Fig. 2, samples such as blood samples or urine samples examined.

Fig. 2 shows the optical sensor 1 in a sensor array on the automatic analyzer 11. With the optical sensor 1 is carried out a detection of codes on a sample carrier 12, a so-called rack, which, as shown in Fig. 2 with the arrow is inserted in an insertion direction in the automatic analyzer 11. The insertion of the sample carrier 12 is preferably carried out manually by an operator. On the sample carrier 12 sample containing sample tubes 13 are stored, which are examined by inserting the sample carrier 12 in the automatic analyzer 11.

Fig. 3 shows a first embodiment of a sample carrier 12. The sample carrier 12 has a linear array of receptacles 14, in which the sample tube 13 can be adjusted. The sample tubes 13 can be closed with a sealing plug 15.

For identification of each sample, a barcode 6 is applied to the respective sample tube 13. For a clear assignment and tracking of the sample, it is also necessary that the position of the sample tube 13 can be securely detected. For this purpose, each receptacle 14 of the sample holder 12 is assigned a position code 16 which is arranged below this receptacle 14 and which uniquely identifies the position of the receptacle 14. The position codes 16 are formed as two-dimensional codes. All position codes 16 for a sample carrier 12 are arranged in predetermined nominal positions on a belt 17, which in the present case is formed by a film. The tape 17 is glued in one step on the sample carrier 12 in a desired position. As a result, the position codes 16 of the band 17 are automatically assigned to the respective recordings 14 correctly.

During the insertion of the sample carrier 12 into the automatic analyzer 11, the codes arranged on the sample carrier 12 are successively detected with the optical sensor 1. The optical sensor 1 is arranged so that its detection range E (in Fig. 3 denoted by E) to the geometries of the sample tube 13 and the associated codes is adapted so that with an image of a recording 14 associated position code 16 and at the same time Barcode 6 of the stored in this receptacle 14 sample tube 13 is detected.

During the insertion process, the optical sensor 1 generates images at a predetermined frame rate. During this insertion process, no complete evaluation of these images takes place. Rather, in the evaluation unit 9 of the optical sensor 1 is checked for each image, whether a position code 16 has been detected and whether this is in the desired range P of the detection range E shown in Fig. 3. In this case, only the code information of the position code 16 is decoded. This code information is used as an index under which an image containing the position code 16 in the target area P is stored. This evaluation takes place in real time, that is during the execution of the insertion process.

The further evaluation of the images thus stored under the indexes is not in real time but time-relaxed, that is in a larger time frame, after completion of the insertion process. In this case, for the detection and decoding of the bar code 6, the position code 16 defining the index of the image is only searched in the area exactly above the position code 16. Thus, the defined spatial assignment of the barcode 6 of the sample tube 13 to the respective position code 16 is utilized, so that a fail-safe, unambiguous assignment of the barcode 6 to the position code 16 is provided.

In order to obtain further information about the sample tube 13, in addition, the entire image content of a captured with the optical sensor 1 and stored under an index image can be evaluated. For example, the height or the diameter of the sample tube 13 can be determined. Additionally or alternatively, it can be checked whether the sample tube 13 is closed with a sealing plug 15.

4 and 5 show a second embodiment of a sample carrier 12. In this case, the position codes form 16 individual, separate barcodes. In this case, to identify a receptacle 14, the respective position code 16 is fixed laterally next to the receptacle 14 on the sample carrier 12. In the present case, the position code 16 for a receptacle 14 is attached to the left of this receptacle 14. Also in this embodiment, there is always an exact, predetermined spatial assignment of the position code 16 to the bar code 6 of the sample tube 13, which is inserted into the receptacle 14 associated with the position code 16. This is shown in particular in FIG. 5.

Accordingly, again takes place during the insertion process one of acquisition images within the detection range E by the optical sensor 1 with a predetermined frame rate. In this case, an evaluation of partial information of the images takes place during the insertion process in real time in such a way that it is checked whether a position code 16 is present in the target area P shown in FIG. 5 within the coverage area E, ie the image generated with the area camera 7. Only if this is the case, the image is stored under the index formed by the position code 16.

After completion of the insertion process is then carried out in the computer unit, the further image analysis of the images stored under the indexes to detect the position code 16 associated barcode 6. Furthermore, in turn, additional features of the sample tube 13 can be determined, such as its height or diameter and whether the sample tube 13 is closed with the closure plug.

LIST OF REFERENCES (1) Optical sensor (2) Housing (3) Illumination unit (4) Light beams (5) Exit window (6) Bar code (7) Area camera (7 a) Pixel

Claims (12)

(8) Optical element (9) Evaluation unit (10) Depth of field (11) Automatic analyzer (12) Sample carrier (13) Sample tube (14) Holder (15) Sealing plug (16) Position code (17) Band (E) Detection range (P) Target range Patent claims 1. Method for code detection by means of a sensor arrangement with an optical sensor (1), comprising an area camera (7) with a matrix-like arrangement of pixels (7a) and an evaluation unit (9) in which output signals of the pixels (7a) are used for decoding codes the area camera (7) are evaluated, characterized in that with the optical sensor (1) codes on a sample carrier (12) during an insertion process are detected, wherein the sample carrier (12) receptacles (14) for sample tube (13), and wherein as first codes on the sample carrier (12) positions of the respective receptacles (14) characterizing position codes (16) are provided as second codes on the sample tube (13) there are provided sample-identifying barcodes (6) which in a predetermined position relative to the assigned position code (16) are arranged so that they are detectable with an image pickup by the optical sensor, that during the Insertion process is detected with the optical sensor (1) image is evaluated only on the presence of the position code (16) and upon detection of the position code (16) the image with the determined position code (16) is stored as an index, and that after completion of the insertion process for each recorded with an image recording barcodes (6) and position codes (16) the evaluation of the stored images is such that the barcodes (6) in the evaluation unit (9) decoded and assigned to the respective position codes (16) based on the indices. 2. The method according to claim 1, characterized in that the position codes (16) form an arrangement of separate codes, wherein in each case a position code (16) in a predefined position relative to the associated receptacle (14) for a sample tube (13) is arranged. 3. The method according to claim 2, characterized in that the position code (16) is arranged laterally to the associated receptacle (14). Method according to claim 1, characterized in that the position codes (16) are constituents of a tape (17) forming a position scale, each position code (16) being in a predefined position relative to the associated receptacle (14) for a sample tube (13 ) is arranged. 5. The method according to claim 4, characterized in that the position code (16) is arranged below the associated receptacle (14). 6. The method according to any one of claims 1 to 5, characterized in that a position code (16) in a predetermined image area of the area camera (7) is received. 7. Method according to claim 6, characterized in that the bar code (6) assigned to the position code (16) is searched only within an image section of an image of the area camera (7), the position and size of the image section being determined by the image area of the position code (16 ) is determined. 8. The method according to any one of claims 1 to 7, characterized in that on the basis of a stored image with an index image in the image analysis after completion of the insertion process next to the bar code (6) further features of the sample tube (13) are detected. 9. The method according to claim 8, characterized in that the further features include geometric data of the sample tube (13). 10. The method according to any one of claims 8 or 9, characterized in that as a further feature, the presence of a plug on the sample tube (13) is checked. 11. The method according to any one of claims 1 to 10, characterized in that the image evaluation during the insertion process in the evaluation unit (9) of the optical sensor (1). 12. The method according to any one of claims 1 to 11, characterized in that the image evaluation takes place after completion of the insertion process in a separate computer unit.