Method and related apparatus for detecting the presence of a sample

Abstract

Method for detecting the presence of a sample and related apparatus The present invention relates to a method for detecting the presence of a liquid inside a well of a transparent or translucent support intended for analysis performed in a device for in vitro detection and / or quantification, where the presence of a liquid is assessed based on a visible pattern likelihood index, which represents the probability that an expected pattern is legible within the field of view of an imager. The invention makes it possible to prevent assays from being performed without a sample, and can be applied without wasting sample or sample well supports if the sample well is not filled by the user. Furthermore, the method allows for accurate detection of transparent or translucent samples with low reflectance.

Description

Technical Field

[0001] The present invention relates to a detection method for detecting the presence of a liquid in a well before analysis of the liquid in an analyzer. More specifically, the liquid can be a biological sample, and the device for implementing the detection method can be configured for in vitro detection and / or quantification of at least one analyte in the biological sample. Therefore, the present invention can be used in an automated device for in vitro diagnosis in the clinical and industrial fields. In particular, the present invention can be applied within the scope of the commercially available instrument VIDAS® by the applicant.

Background Art

[0002] When performing a biological assay, depending on the type of biological assay, before starting any of the following optional operations such as detection and quantification of microorganisms / analytes, the user must pre-fill the sample well with the sample. The results of some assays may be incorrect because the device that is supposed to analyze the sample cannot detect this type of error (absence or shortage or insufficiency of the sample) when the step of manual introduction of the sample is simply omitted or performed incorrectly.

[0003] From WO 2010 / 029471, a method for determining the presence of a sample on a sample receiving surface, comprising: (i) using an optical element arranged in near-field contact with the sample receiving surface to guide an incident light beam onto the sample receiving surface; (ii) using a photodetector to determine the reflected light intensity in the emitted light that has undergone total internal reflection inside the optical element; and (iii) comparing the reflected light intensity with a predetermined light intensity, the result of the comparison indicating the presence of the sample on the sample receiving surface, is known.

[0004] There are many different methods for detecting the presence of a sample inside an analytical instrument using light reflectance analysis. The problem arises when the sample is transparent and has low reflectivity. In fact, detecting the presence of a sample inside a well is extremely difficult. Furthermore, if the well is made of transparent plastic, the interference of reflectivity complicates the detection of its presence. [Overview of the Initiative]

[0005] One of the main objectives of the present invention is to provide a detection method that enables the detection of the presence of a liquid in at least one well that is transparent or translucent and has at least partially low reflectivity. Obviously, this detection method according to the present invention can be applied to any type of well and any type of liquid, but liquids that cause reflectivity problems and cannot be easily detected by the prior art will be described in detail below. The objective of this method is to enable a simple automated process to avoid starting an analysis with a defective well and to enable the correction of errors before the start of the analysis.

[0006] Therefore, the object of the present invention is a method for detecting the presence of liquid inside a well of a transparent or translucent support, which is intended for analysis to be performed in an automated apparatus for, for example, in vitro detection and / or quantification. A. A step of providing a system, wherein the system A support having at least one well configured to be filled with a liquid for analysis, For example, an apparatus for in vitro detection and / or quantification, wherein the apparatus is • A base configured to accept at least one support, • One control unit that stores at least one reference image, and - An imager having a field of view, controlled by a control unit, configured to acquire at least one image of the field of view, the control unit configured to process at least one image acquired by the imager, A device equipped with, At least one pattern comprising at least one linear portion, wherein the pattern is positioned such that the liquid to be analyzed at least partially overlaps it when the well is filled, and the reference image corresponds to at least one image of the pattern acquired without the liquid overlapping the support and the pattern. The steps include providing a system that includes, B. A step of loading a support onto the base of the device, wherein at least one well of the support is positioned within the field of view, C. A step of acquiring at least one image of the field of view by an imager, D. The step of transmitting the acquired image to the control unit, E. The position of the pattern in the acquired image, E1. Performing at least multiple first scans along a first direction, wherein the first scans are dispersed in directions different from the first direction. E2. Determine multiple matching descriptors that indicate whether the first scan crossed the linear part of the pattern. E3. Performing at least a plurality of second scans that extend in a second direction and are dispersed apart from each other in a first direction, wherein the second scans scan along the first direction, E4. Determine at least one line similarity descriptor that indicates whether the second scan overlaps with the pattern at least partially. The steps determined by, F. A step of evaluating the presence of liquid in a well of a support, based on a percentage index of the visible pattern likelihood, which represents the probability that the linear part of a predicted pattern within the field of view is legible, wherein the percentage index of the visible pattern likelihood is a function of the coincidence descriptor and the line similarity descriptor, and The objective is to provide a detection method that includes at least the following:

[0007] First, the detection method of the present invention makes it possible to prevent, for example, the execution of an assay without a sample, and can be applied without wasting liquid or support if the user has not filled the well. Furthermore, this method enables the accurate detection of the presence of transparent or translucent, low-reflectivity liquids. In fact, this method makes it possible to detect any deformation or disappearance of a pattern caused by the presence of liquid in the well. This type of method can be applied to any sample that is very difficult to see when it is in the well. Advantageously, this method can be effective with opaque liquids, as the pattern cannot be detected in the case of opaque liquids (it is completely masked by the opacity of the liquid).

[0008] Another advantage of this detection method is that the detection is non-contact. In fact, the detection is performed via a support, and no probes or other devices that could contaminate the liquid, or more specifically the biological sample, are used.

[0009] The methods of the present invention are advantageously completed by the following different features, either individually or in various possible combinations thereof.

[0010] According to one feature of the present invention, the liquid is a biological sample, and at least one well is a sample well.

[0011] Advantageously, the control unit stores a reference image corresponding to at least one image of the pattern acquired without the support and any liquid overlapping with the pattern, meaning there is no partial or complete overlap of the liquid-filled support, preferably at least no wells of the support that are liquid-filled and overlap with the pattern. The purpose of this reference image is to acquire an image of the pattern without any deformation that may be caused by the material or any medium. The reference image makes it possible to determine the expected spatial location and characteristics (shape, gradation) of the pattern, i.e., the algorithm of the control unit will search for the pattern in the field of view during the detection method according to the present invention.

[0012] Preferably, the reference image is made binary thanks to a predetermined threshold, which is achieved by minimizing the interclass variance of the image histogram according to Otsu's method. The pattern of the reference image is placed in regions of the picture where the pixels are set to 1.

[0013] According to one feature of the present invention, the method may include the step of performing a calibration procedure to adjust the position of a known pattern from a reference image in order to take into account any mechanical drift.

[0014] According to one feature of the present invention, the first scan is a scan along the vertical direction, the first scan is performed at a predetermined position, and at least one of the first scans is performed in the center of the field of view.

[0015] According to one feature of the present invention, the first scan is dispersed in the horizontal direction.

[0016] According to one feature of the present invention, the first scans are dispersed and separated from each other.

[0017] According to one feature of the present invention, each scanning region of each first scan is distinct.

[0018] According to one feature of the present invention, the multiple first scans include at least three first scans, including one performed in the center of the imager's field of view, which is referred to as the "centered first scan".

[0019] Preferably, the other first scan is positioned entirely within the field of view.

[0020] Preferably, the other first scans are dispersed over a determined distance relative to the first scan performed in the center. More preferably, the other first scans are arranged symmetrically with respect to the first scan performed in the center.

[0021] According to one feature of the present invention, each first scan has a width of at least one pixel. Preferably, a width of 2 to 5 pixels is selected, because a width of 2 to 5 pixels is sufficiently robust against artifacts and makes it possible to avoid losing information about the image due to the averaging step. From each first scan, if the width of each first scan is greater than one pixel, the average value of the pixels at the same height is calculated to obtain a linear array.

[0022] According to one feature of the present invention, each first scan scans a line of pixels having a width of at least one pixel, and for each scanned line, a tone value is determined by calculating the average of the tones of the pixels of the scanned line.

[0023] According to one feature of the present invention, in sub-step E2, the control unit considers that the first scan has crossed the linear part of the pattern if the tone peaks of each first scan have the same coordinates and the same amplitude.

[0024] According to the present invention, assuming that the linear part of the pattern is within the field of view, the first scan performed in the center is limited to having at least one tone peak. If there is no tone peak for the first scan performed in the center, the control unit considers that the linear part of the pattern is invisible and thus that there is liquid within the field of view. If there is at least one peak of tone for the first scan performed in the center but no tone peak for one of the other first scans, the other first scan is repeated and the X coordinate is adjusted by the determined number of pixels.

[0025] According to one feature of the present invention, the adjustment of the number of pixels for a new vertical scan is determined by performing only a shift of the pixel values, which depends on some factors among the resolution of the imager and its proximity to the surface on which the pattern is etched.

[0026] According to one feature of the present invention, the matching descriptors include position descriptors and amplitude descriptors. The advantage of having at least two different types of matching descriptors, particularly position descriptors and amplitude descriptors, is that it provides an efficient system that can detect the presence of liquid and cross-reference information to achieve accuracy. In fact, if the method were based solely on position descriptors or solely on amplitude descriptors, the method may lose its effectiveness, as liquid can alter the gradation of limited portions of the pattern, and if only position descriptors are used, it may lead to detection failure.

[0027] Since the pattern position is known from the calibration procedure and / or based on the reference image, the average peak position for each scan is expected to be within the determined range, and in fact, the pattern position is located within the experimentally evaluated tolerance range.

[0028] According to one feature of the present invention, the position descriptor includes (i) an absolute position descriptor representing the position of each first scan's tone peak within a determined range, and (ii) a relative position descriptor representing the distance between each tone peak in each first scan.

[0029] According to one feature of the present invention, the absolute position descriptor of a first scan is obtained by comparing the position of the grayscale peak of the first scan with a reference position independent of the positions of other first scan peaks, and the value of the absolute position descriptor increases by a determined score, for example, 1, if the grayscale peak of the first scan is found by the control unit within a determined range, and each first scan has a grayscale peak.

[0030] This applies to each first scan and each first scan that has a peak within the expected range.

[0031] According to one feature of the present invention, if the value of this descriptor is 0, it means that no peak is found in any of the n scans, and that the liquid is detected as something that makes the pattern invisible to the imager. TIFF0007850155000001.tif10170

[0032] According to one feature of the present invention, a relative position descriptor is obtained by comparing the position of the tone peak of each first scan with the average peak position corresponding to the average of the positions of the tone peaks of each first scan. On a pixel-by-pixel basis, if the distance between the tone peak position and the average peak position is within the expected range, the relative position descriptor has a predetermined score. On a pixel-by-pixel basis, if the distance between each peak and the average peak position is outside the expected range, the relative position descriptor has a score of 0. This applies to each first scan and each first scan having peaks within the expected range. TIFF0007850155000002.tif24170

[0033] According to one feature of the present invention, the amplitude descriptor is calculated for each tone peak according to the following formula. TIFF0007850155000003.tif11170

[0034] If the difference in tonal values ​​between each peak and the average peak amplitude falls within the expected range, the amplitude descriptor value increases by a score of 1. The limit of the expected range is the absolute value of the tonal values, since the tonal values ​​are normalized and distributed across the entire range (0 to 255) by pre-processing the image.

[0035] If the grayscale distance between each peak and the average peak amplitude is outside the expected range, the resulting amplitude descriptor score is 0.

[0036] According to one feature of the present invention, all matching descriptors are summed together to form a "whole descriptor" for the first scan.

[0037] According to the present invention, the possible translation of patterns or glare caused by the presence of liquid can lead to outliers in the grayscale peaks.

[0038] According to one feature of the present invention, if a grayscale peak is found outside the expected range with an amplitude exceeding a predetermined threshold x% of the average amplitude of peaks found within the expected range, for example 50%, the overall descriptor is reduced by 1 for each peak outlier found. TIFF0007850155000004.tif23170 Total descriptor = absolute position descriptor + relative position descriptor + amplitude descriptor + outlier descriptor

[0039] According to one feature of the present invention, the second scan is a scan along the horizontal direction, and the second scan is performed at a predetermined position.

[0040] According to one feature of the present invention, the second scan is dispersed in the vertical direction.

[0041] According to one feature of the present invention, the second scans are dispersed and separated from each other.

[0042] According to one feature of the present invention, each scanning region of each second scan is separate.

[0043] According to one feature of the present invention, the multiple second scans include at least three second scans, including one performed in the center of the imager's field of view, which is referred to as a "central second scan."

[0044] Preferably, the other second scans are positioned entirely within the field of view and dispersed at a determined distance compared to the central second scan. More preferably, the other second scans are positioned above and below the central second scan.

[0045] According to one feature of the present invention, each second scan scans at least one row of pixels, the height of which is at least one pixel, and the grayscale value is determined by calculating the average of the grayscale values ​​of the pixels in the scanned row for each scanned row. If the height of the scanned row is greater than one pixel, the average value of the scanned row is calculated.

[0046] According to one feature of the present invention, steps E1 and E2 are performed before steps E3 and E4. Alternatively, steps E3 and E4 are performed before steps E1 and E2.

[0047] According to one feature of the present invention, n grayscale functions are determined by comparing the grayscale values ​​of a second scan performed in the center with those of another second scan point-to-point.

[0048] According to one feature of the present invention, at least a first grayscale function is determined by the point-to-point difference between the grayscale value of the central second scan and the grayscale value of at least one upper second scan.

[0049] According to one feature of the present invention, at least a second grayscale function is determined by the point-to-point difference between the grayscale value of the central second scan and the grayscale value of at least one lower second scan.

[0050] According to one feature of the present invention, if there are multiple upper second scans, only the upper second scan with the highest average value of grayscale can be considered.

[0051] According to one feature of the present invention, if there are multiple lower second scans, only the lower second scan with the highest average value of grayscale can be considered.

[0052] According to one feature of the present invention, substep E4, which is to determine at least one line similarity descriptor, (i) A substep of determining n tone functions based on a point-to-point comparison between the tone values ​​of a second central scan and the tone values ​​of at least one other second scan, (ii) A substep in which the value of the line similarity descriptor is determined based on the previously determined grayscale function. Includes.

[0053] According to one feature of the present invention, if all grayscale functions are negative, the line similarity descriptor is considered null, and if at least one grayscale function is positive, the line similarity descriptor is considered non-null, and therefore the linear part of the pattern of the acquired image may be readable by the imager.

[0054] According to one feature of the present invention, the method includes step E5 of determining the profile of the linear part of the pattern, which is to compare the average tonal values ​​of each tone function with respect to each other, and the tone function having the highest average tonal value is considered by the control unit to represent the most likely profile of the linear part of the pattern of the acquired image. Advantageously, the average value of a tone function is the sum of all points of the function divided by the number of points of the function. If there are several tone functions, the one used in the algorithmic step is selected from the others, specifically, only the one with the highest average value proceeds to the next step.

[0055] Conversely, if the control unit considers it compatible with the absence of liquid in its field of view, it means the control unit considers there is no liquid in the well. Conversely, if the control unit considers it incompatible with the absence of liquid in its field of view, it means the control unit considers there is liquid in the well.

[0056] According to one feature of the present invention, step F includes a substep F1 that normalizes the global descriptor and the line similarity descriptor.

[0057] According to one feature of the present invention, the normalization of the whole descriptor is performed by converting the range [-N, 3*n times first scan] to the range [0, 100], where, Since we can give +1 for absolute position descriptors, +1 for relative position descriptors, and +1 for amplitude descriptors, 3 is the maximum value of each descriptor in the n first scans. • N is the number of outlier descriptors that each contribute -1.

[0058] According to one feature of the present invention, normalization of the line similarity descriptor is performed by converting the range [0~MAX] to the range [0~100], where MAX = N points * 1,5 of the scan, and MAX is the maximum possible value of the line similarity descriptor.

[0059] According to one feature of the present invention, step F is performed by normalizing the whole descriptor and the normalized line similarity descriptor as follows: Visible pattern likelihood index = Normalized line similarity descriptor / 2 + Normalized overall descriptor / 2 This includes a substep F2 that averages the results.

[0060] According to one feature of the present invention, if the visible pattern likelihood index is within a determined range, the pattern in the acquired image is in the expected position based on the reference image, and therefore the control unit considers it to be compatible with the absence of liquid in the field of view.

[0061] According to one feature of the present invention, if the percentage index is outside the determined range, the pattern of the acquired image is not in the expected position based on the reference image, and the control unit considers it incompatible with the absence of liquid in the field of view.

[0062] According to one feature of the present invention, the determined range of the visible pattern likelihood index is 65% to 85%.

[0063] Another object of the present invention is a system for in vitro detection and / or quantification of at least one analyte in a biological sample, a. A support having at least one well configured to hold a liquid, and at least partially transparent or translucent support, b. A device, A base configured to accept at least one support, One control unit, and An imager having a field of view, controlled by a control unit, and configured to acquire an image of at least one well of at least one support, A device equipped with Equipped with, The system is characterized in that it includes at least one pattern which includes at least one linear section and is intended to overlap at least partially with the liquid, an imager is configured to acquire at least one image of the field of view, and a control unit is configured to determine the presence of liquid in the well based on the at least one image acquired by the imager.

[0064] According to the present invention, the linear portion of a pattern is the part of the pattern composed of points that form a straight line.

[0065] Advantageously, the opening through which the imager sees is not circular but rather elliptical, and therefore, linear parts of the pattern are more likely to be seen when the linear parts extend horizontally rather than vertically.

[0066] Advantageously, the linear portion of the pattern simplifies the algorithm compared to other parts of the pattern because it can be subjected to basic computer vision mechanisms such as vertical scanning of the image, as well as checking for transitions from "white" to "black" and vice versa.

[0067] According to one feature of the present invention, the pattern is positioned directly on the base of the device.

[0068] Alternatively, according to one feature of the present invention, the pattern is positioned directly on the back of the support, preferably on the back of at least one well of the support.

[0069] According to one feature of the present invention, the pattern is engraved by laser etching or marked or engraved by any suitable technique known.

[0070] According to one feature of the present invention, outliers in the grayscale peaks represent a deformation of at least a portion of the pattern.

[0071] For the purposes of this invention, it should be noted that the acquired image consists of multiple lines and rows of pixels. Furthermore, the acquired image is in bitmap or JPEG format.

[0072] According to one feature of the present invention, the pattern extends along the entire length of the base, or the pattern is repeated along the entire length of the base.

[0073] According to one feature of the present invention, when the support is positioned on the base, the pattern or a portion of the pattern is visible in at least one well of the support, preferably in each well. These configurations allow detection to be applied to any of the wells of the support by selecting the corresponding region of interest.

[0074] According to one feature of the present invention, the pattern includes at least one linear portion extending horizontally.

[0075] Advantageously, the pattern shape and geometric form are appropriately selected to amplify the effects of image distortion and provide robustness to all mechanical tolerances (camera position, etched mark position, VIDAS strip position, strip manufacturing tolerances, etc.). For example, a grid is a planar pattern with a geometric form such that the image is unaffected by XY position errors and tolerances. Specifically, a grid-shaped pattern covering the entire region of interest can remain visible even if the camera moves to some extent in the X and Y directions. Another possible option for the pattern may be some kind of triple intersection, or a pattern that looks like a planar pattern but has central elements (pillars) that can allow for the detection of changes in size.

[0076] According to one feature of the present invention, the imager is a 2D camera device.

[0077] According to one feature of the present invention, the imager is configured to acquire and decode an identification code of a support when it is framed within the field of view, and to transmit the decoded identification code to a control unit. The imager is also advantageously configured to acquire an image of the field of view and to transmit the image of the field of view to a control unit equipped with a computer vision algorithm for pattern recognition.

[0078] According to one feature of the present invention, the identification code may be a linear or 2D code.

[0079] According to one feature of the present invention, the imager is positioned above the sample well of the support in order to frame the region of interest within the entire image.

[0080] According to one feature of the present invention, the imager is mounted and assembled with an illumination system that enables robust embedded applications, even in the case of partial or complete ambient light exposure. Thus, an additional external illumination system is unnecessary. The lower position of the well where the pattern exists is only slightly exposed to stray light not provided by the imager illuminator, thus enhancing resistance to ambient light.

[0081] According to one feature of the present invention, the imager is positioned such that the optical axis of the imager is directed toward an axis that forms an angle (a) with the base of the apparatus, and the angle is in the range of 67° to 77°. Since the optical axis is perpendicular to the base, an angle of 90° is excluded, in which the light from the illumination system is reflected and thus hinders the recognition of the pattern when the sample well is empty. The selected range of angles allows for proper framing of the pattern and the bottom of the well.

[0082] For example, the identification code indicates the type of reagent and / or the manufacturing lot number.

[0083] The control unit features a computer vision algorithm embedded in the firmware of the electronic board to which the imager is connected.

[0084] According to one feature of the present invention, the support of the system comprises at least one sample well into which a biological sample is intended to be placed.

[0085] According to one feature of the present invention, the sample well is positioned within the field of view of the imager in order to frame it within the field of view of the entire image.

[0086] According to one feature of the present invention, the sample well is transparent or translucent. [Brief explanation of the drawing]

[0087] The present invention is given as a non-limiting example and will be better understood by the following description of embodiments according to the present invention, which are described with reference to the attached schematic diagrams. The attached schematic diagrams are listed below. [Figure 1] This is a diagram of the apparatus of the present invention. [Figure 2] This is a schematic diagram of the system of the present invention. [Figure 3] This is a partial view of the base of the apparatus of the present invention, which has a support on top. [Figure 4] This is a partial view of the base of the device of the present invention. [Figure 5] This is a diagram of possible patterns etched onto the base of the apparatus of the present invention. [Figure 6] This is a diagram of possible patterns etched onto the base of the apparatus of the present invention. [Figure 7] This is a diagram of possible patterns etched onto the base of the apparatus of the present invention. [Figure 8] This is an image of the base of the apparatus of the present invention, which lacks a support, captured within the field of view of the imager. [Figure 9] This is an image taken within the field of view of the imager of the base of the apparatus of the present invention, which has an empty support on top. [Figure 10] This is an image taken within the field of view of an imager of the base of the apparatus of the present invention, which has a liquid-filled support on top. [Figure 11] This is a schematic diagram of the steps of the method of the present invention. [Modes for carrying out the invention]

[0088] The present invention relates to a method for detecting the presence of a liquid and a system 100 for carrying out this detection method.

[0089] First, the system 100 of the present invention will be described with reference to Figures 1 to 4.

[0090] According to the present invention, the system 100 of the present invention is a system for in vitro detection and / or quantification of at least one analyte in a biological sample. Therefore, it is preferable that the detection method of the present invention be carried out to detect the presence of the biological sample in liquid form in the system before processing the in vitro detection and / or in vitro quantification.

[0091] System 100 comprises a support 110 and a device 120.

[0092] The support 110 is advantageously a strip having several wells 111. One well 111 is dedicated to receiving the biological sample to be tested and is called the sample well. The sample well 111 is transparent or translucent at least at the bottom. Preferably, according to the present invention, the support is completely translucent or transparent. The biological sample to be analyzed is in liquid form, which is manually placed into the sample well 111. The support comprises a foil 112 that seals and covers the support 110, the foil 112 having a breakable window 113 positioned in front of the wells 111. The support 110 comprises at least one identification code 114, such as a QR code or barcode, marked on a label of the foil 112, as shown in Figure 3. For example, the identification code indicates the type of reagent and / or manufacturing lot number.

[0093] The window 113 is intended to be punctured by at least one pipette tool (not shown) for mixing the contents of the wells together, washing the liquid, or transferring the liquid from one well to another.

[0094] The apparatus 120, shown in Figure 1 and as shown in Figure 2, comprises a base 121 configured to receive a plurality of supports 110, a control unit 122, and an imager 123 having a field of view.

[0095] According to the present invention, the imager 123 is controlled by a control unit 122 and is configured to acquire an image of the field of view, and therefore of at least one well 111 of the support 110, when the support 110 is within the field of view of the imager 123. The imager 123 is preferably a 2D camera device configured to acquire and decode an identification code 114 of the support 110 or a data matrix of a disposable cone (not shown) when either is framed, and to transmit the decoded text to the control unit 122. The imager 123 includes an illumination system 1231 as shown in Figure 2. According to the embodiment shown in Figure 2 and the present invention, the imager 123 is positioned such that the optical axis of the imager 123 is directed on axis XX, which forms an angle with the base 121 of the device 120, and the angle is in the range of 67° to 77°.

[0096] The control unit 122 is equipped with a computer vision algorithm for pattern recognition, which is incorporated into the firmware of the electronic board to which the imager 123 is connected. Advantageously, the computer vision algorithm utilizes how the presence of liquid affects the image of a known pattern; depending on its transparency, in the presence of opaque liquid the marks simply become invisible, while in the presence of transparent or translucent liquid in the well the image of the marks is distorted and / or shifted, or simply becomes invisible (see Figure 10), with the liquid acting as a lens set. Furthermore, if present, the liquid reflects light emitted by the camera's illumination system, and the resulting glare in the image may interfere with pattern recognition.

[0097] According to the present invention, the system 100 comprises at least one pattern 130 including at least one horizontally extending linear section 131, as shown in Figures 5 to 8. The pattern 130 is intended to at least partially overlap with the liquid that is believed to be in the well 111 within the field of view of the imager 123. The imager 123 is configured to acquire at least one image of the field of view, and the control unit 122 is configured to determine the presence of the liquid in the well 111 based on the at least one image acquired by the imager 123.

[0098] Possible patterns are shown in Figures 5 to 7.

[0099] Figure 5 shows a pattern 130 according to the present invention, which corresponds to the linear portion 131 of the pattern and has only one horizontal line extending across the entire width of the support.

[0100] Figure 6 shows another possible embodiment of pattern 130 according to the present invention, which has two lines, and therefore two linear sections arranged at a distance from each other. The two linear sections 131 extend horizontally and are dispersed vertically.

[0101] Figure 7 shows another embodiment of pattern 130 according to the present invention, which has one central linear section 131 and two vertical lines positioned symmetrically with respect to the linear section 131.

[0102] Advantageously, the vertical elements in Figure 7 are not framed by the detection algorithm and are used to facilitate camera centering during device assembly.

[0103] Pattern 130 can be seen through the window 113 of the support when the support 110 is positioned on the base and the window is drilled, as shown in Figure 9.

[0104] In the embodiments shown in Figures 3 and 4, as shown in Figure 3, the pattern 130 is etched directly onto the base 121 of the apparatus, and the support 110 is positioned thereon. Furthermore, to detect any liquid inside any of the wells 111 of the support 110, the pattern 130 is advantageously repeated along the entire length of the base. Once the support 110 is positioned on the base 121, a portion of the pattern or the pattern 130 is visible in at least one well 111, as seen in Figure 9 when no liquid is present in the well. If liquid is present in the well, glare may appear, and pattern distortion may also appear, as shown in Figure 10.

[0105] The detection method according to the present invention will be described below with reference to Figure 11. The detection method includes at least the following steps:

[0106] Step A: Provide the above-described system 100 according to the present invention. Step B: The support 110 is loaded onto the base 121 of the device 120, and at least one well 111 of the support 110 is positioned within the field of view of the imager 123. Step C: The imager 123 acquires at least one image of the field of view. Step D: The acquired image is sent to the control unit 122. Step E: Determine the position of pattern 130 in the acquired image.

[0107] Step E includes at least one first substep E1 which is to perform at least a number of first scans along a first direction, wherein the first scans are distributed in a direction different from the first direction.

[0108] In a preferred embodiment of the present invention, the first scan is a scan along the vertical direction, the first scan is performed at a predetermined position, and at least one first scan is performed in the center of the field of view. Advantageously, the first scans are distributed horizontally, away from each other, with each scanning a distinct area. In a very preferred embodiment, there are at least three first scans, including one performed in the center of the imager's field of view, referred to as the "centered first scan." Preferably, the other first scans are fully positioned within the field of view and distributed at a determined distance relative to the centered first scan.

[0109] In a preferred embodiment of the present invention, each first scan scans a line of pixels that is at least one pixel wide, and the grayscale value is determined by calculating the average of the grayscale values ​​of the pixels in the scanned line for each scanned line. From each first scan, if the width of each first scan is greater than one pixel, the average value of those pixels at the same height is calculated to obtain a linear array.

[0110] Step E is performed after substep E1 and includes at least one second substep E2, which is to determine a plurality of matching descriptors that indicate whether the scan crossed a linear portion of the pattern. In substep E2, the control unit considers that the first scan crossed a linear portion of the pattern if the grayscale peaks of each first scan have the same coordinates and the same amplitude. According to the present invention, the matching descriptors include position descriptors and amplitude descriptors.

[0111] According to the present invention, the position descriptor includes at least (i) an absolute position descriptor representing the position of each first scan's tone peak within a determined range, and (ii) a relative position descriptor representing the distance between each tone peak in each first scan.

[0112] The absolute position descriptor for the first scan is obtained by comparing the position of the grayscale peak of the first scan with a reference position independent of the positions of other first scan peaks. The value of the absolute position descriptor increases by a determined score, for example, 1, if the grayscale peak of the first scan is found by the control unit within a determined range and each first scan has a grayscale peak. On the other hand, if the value of this descriptor is 0, it means that no peak is found in any of the n scans, and the liquid is detected as making the pattern invisible to the imager. TIFF0007850155000005.tif11170

[0113] According to the present invention, a relative position descriptor is obtained by comparing the position of the grayscale peak of each first scan with the average peak position corresponding to the average of the positions of the grayscale peaks of each first scan. On a pixel-by-pixel basis, if the distance between the grayscale peak position and the average peak position is within the expected range, the relative position descriptor has a predetermined score. On a pixel-by-pixel basis, if the distance between each peak and the average peak position is outside the expected range, the relative position descriptor has a score of 0. TIFF0007850155000006.tif25170

[0114] According to one feature of the present invention, the amplitude descriptor is calculated for each tone peak according to the following formula. TIFF0007850155000007.tif10170

[0115] If the difference in tonal values ​​between each peak and the average peak amplitude falls within the expected range, the amplitude descriptor value increases by a score of 1. The limit of the expected range is the absolute value of the tonal values, since the tonal values ​​are normalized and distributed across the entire range (0 to 255) by pre-processing the image.

[0116] If the grayscale distance between each peak and the average peak amplitude is outside the expected range, the resulting amplitude descriptor score is 0.

[0117] According to one feature of the present invention, all matching descriptors are summed together to form a "whole descriptor" for the first scan.

[0118] According to the present invention, the possible translation of patterns or glare caused by the presence of liquid can lead to outliers in the grayscale peaks.

[0119] According to one feature of the present invention, if a grayscale peak is found outside the expected range with an amplitude exceeding a predetermined threshold x% of the average amplitude of peaks found within the expected range, for example 50%, the overall descriptor is reduced by 1 for each peak outlier found. TIFF0007850155000008.tif23170 Total descriptor = absolute position descriptor + relative position descriptor + amplitude descriptor + outlier descriptor

[0120] Step E is performed after E1 and E2, and involves performing at least a number of second scans that extend in a second direction and are dispersed apart from each other in the first direction, wherein the second scans include a third substep E3 that scans along the first direction. In a preferred embodiment, the second scans are scans along the horizontal direction and are performed at a predetermined location, with at least one second scan performed in the center of the field of view. Furthermore, the second scans are dispersed apart from each other in the vertical direction, and each scanning region of each second scan is distinct.

[0121] In a preferred embodiment, the multiple second scans include at least three second scans, including one performed in the center of the imager's field of view, referred to as the "centered second scan." Preferably, the other second scans are positioned entirely within the field of view and dispersed at a distance determined relative to the centered second scan. More preferably, the other second scans are positioned above and below the central second scan. Furthermore, each second scan scans at least one row of pixels, which is at least one pixel high, and the tonal value is determined by calculating the average of the tonal values ​​of the pixels in the scanned row for each scanned row. If the height of the scanned row is greater than one pixel, the average value of the scanned row is calculated.

[0122] Step E is performed after E3 and includes a fourth substep E4, which is to determine several line similarity descriptors that indicate whether the scan overlaps with the pattern at least partially.

[0123] Substep E4 includes a substep in which at least a first tone function is determined by the point-to-point difference between the tone value of the central second scan and the tone value of at least one upper second scan, and at least a second tone function is determined by the point-to-point difference between the tone value of the central second scan and the tone value of at least one lower second scan.

[0124] If all grayscale functions are negative, the line similarity descriptor is considered null; if at least one grayscale function is positive, the line similarity descriptor is considered non-null, and therefore the linear part of the pattern in the acquired image may be readable by the imager.

[0125] Step E includes a fifth substep E5 which determines the profile of the linear part of the pattern, comparing the average tonal values ​​of each tone function to each other, and the tone function with the highest average tonal value is considered by the control unit to represent the most likely profile of the linear part of the pattern of the acquired image. Advantageously, if the control unit considers it appropriate that there is no liquid in the field of view, it means the control unit considers there is no liquid in the well. Advantageously, if the control unit considers it inappropriate that there is no liquid in the field of view, it means the control unit considers there is liquid in the well.

[0126] In a preferred embodiment of the present invention, steps E1 and E2 are performed before steps E3 and E4, but in an alternative embodiment, steps E3 and E4 may be performed before steps E1 and E2.

[0127] Ideally, in the absence of a sample, the most likely profile for the linear portion of the pattern should be very similar to the second scan performed in the center, and indeed, any other second scan subtracted from the second scan performed in the center would likely be input to zero or very low values ​​(almost black dots).

[0128] Each point in the most likely profile is evaluated for its range from the second scan performed in the center. Specifically, multiple ranges exist, and for each range, a score is assigned according to each point in the most likely profile, and these scores are accumulated to calculate a line similarity descriptor.

[0129] Such a range can be defined in absolute terms because the grayscale is normalized and distributed across the entire range (0-255) by pre-processing the image. Alternatively, if normalization is not performed, the expected range can be determined as a specific proportion of the central scan values.

[0130] According to the present invention, the detection method includes step F, which is to assess the presence of liquid in the well of the support based on a percentage exponent of the visible pattern likelihood, which represents the probability that the linear part of the predicted pattern is legible within the field of view, and the percentage exponent of the visible pattern likelihood is a function of the coincidence descriptor and the linear similarity descriptor.

[0131] Step F includes a substep F1 that normalizes the global descriptor and the line similarity descriptor. Normalization of the global descriptor is performed by converting the range [-N, 3*n times the first scan] to the range [0, 100], where, Since 3 can be assigned +1 to the absolute position descriptor, +1 to the relative position descriptor, and +1 to the amplitude descriptor, it is the maximum value of each descriptor in the n first scans. • N is the number of outlier descriptors that each contribute -1.

[0132] Furthermore, step F processes the normalized global descriptor and the normalized line similarity descriptor as follows: Visible pattern likelihood index = Normalized line similarity descriptor / 2 + Normalized overall descriptor / 2 This includes a substep F2 that averages the results.

[0133] If the visible pattern likelihood index is within the determined range, the pattern in the acquired image is in the expected position based on the reference image, and therefore the control unit considers it to be consistent with the absence of liquid in the field of view. If the percentage index is outside the determined range of 65% to 85%, and the pattern in the acquired image is not in the expected position based on the reference image, the control unit considers it to be inconsistent with the absence of liquid in the field of view.

[0134] If the control unit detects a shortage of liquid in a well, the entire loading process (all supports) is stopped in at least one support (if several supports are loaded at the base), and the user is warned by a display, an audible alarm, or both, to repair and refill the identified empty well. Once the well is filled, the process can continue.

[0135] Naturally, the present invention is not limited to the embodiments illustrated in the description and accompanying drawings. Modifications are still possible, particularly in terms of the configuration of various elements, or by substitution of technical equivalents, without departing from the scope of protection of the present invention as defined by the claims.

Claims

1. A method for detecting the presence of liquid inside a well of a transparent or translucent support, which is intended for analysis to be performed in a device for in vitro detection and / or quantification, A. A step of providing a system (100), wherein the system (100) A support (110) having at least one well (111) configured to be filled with a liquid for analysis, An apparatus (120) for in vitro detection and / or quantification, wherein the apparatus (120) - A base (121) configured to accept at least one support (110), - One control unit (122) that stores at least one reference image, and - An imager (123) having a field of view, controlled by the control unit, configured to acquire at least one image of the field of view, and configured for processing the at least one image acquired by the imager. The apparatus (120) includes, At least one pattern (130) comprising at least one linear portion (131), wherein the pattern (130) is arranged such that the liquid to be analyzed at least partially overlaps the pattern (130) when the well is filled, and the reference image corresponds to at least one image of the pattern acquired without the support and the liquid overlapping the pattern, and The steps include providing a system (100) that includes the following: B. A step of loading the support (110) onto the base (121) of the device (120), wherein the at least one well (111) of the support (110) is positioned within the field of view, C. The step of acquiring at least one image of the field of view by the imager (123), D. The step of transmitting the acquired image to the control unit (122), E. The position of the pattern in the acquired image, Substep E1. Performing at least multiple first scans along a first direction which is the width direction of at least one pixel of the acquired image, wherein the first scans are distributed in a direction different from the first direction. Substep E2. Determine a plurality of matching descriptors indicating whether the first scan crossed the linear portion of the pattern. Substep E3. Performing at least multiple second scans extending in a second direction which is the height direction of at least one pixel of the acquired image, wherein the second scans are distributed apart from each other in a first direction and scan along the first direction, and the second scans are performed at least multiple times. Substep E4. Determine at least one line similarity descriptor indicating whether the second scan overlaps at least partially with the pattern. The steps determined by, F. A step of evaluating the presence of the liquid in the well (111) of the support (110) based on a percentage index of the visible pattern likelihood, which represents the probability that the linear portion of the pattern predicted within the field of view is legible, wherein the percentage index of the visible pattern likelihood is a function of the coincidence descriptor and the line similarity descriptor. A detection method comprising at least the following.

2. The detection method according to claim 1, wherein the first scan is a scan along a direction perpendicular to at least one pixel, the first scan is performed at a predetermined position, and at least one first scan is performed in the center of the field of view.

3. The detection method according to claim 1 or 2, wherein in the substep E2, the control unit determines that the first scan has crossed the linear portion of the pattern if the grayscale peaks of each first scan, determined by scanning a line of pixels having a width of at least one pixel, have the same coordinates and the same amplitude.

4. The detection method according to claim 3, wherein the matching descriptors include a position descriptor and an amplitude descriptor.

5. The detection method according to claim 4, wherein the position descriptor includes at least an absolute position descriptor representing the position of each first scan's grayscale peak within a determined range, and (ii) a second feature is a relative position descriptor representing the distance between each grayscale peak of each first scan.

6. The detection method according to claim 5, wherein the absolute position descriptor of a first scan is obtained by comparing the position of the grayscale peak of the first scan with a reference position independent of the position of the grayscale peak of other first scans, and the value of the absolute position descriptor is increased by a determined score of 1 if the grayscale peak of the first scan is found by the control unit within a determined range and each first scan has a grayscale peak.

7. The detection method according to claim 5, wherein the relative position descriptor is obtained by comparing the position of the tone peak of each first scan with an average peak position corresponding to the average of the positions of the tone peaks of each first scan, and on a pixel-by-pixel basis, the relative position descriptor has a predetermined score if the distance between the position of the tone peak and the average peak position is within the expected range, and on a pixel-by-pixel basis, the relative position descriptor has a score of 0 if the distance between each peak and the average peak position is outside the expected range.

8. The amplitude descriptor is given by the following equation: A detection method according to any one of claims 4 to 7, wherein each grayscale peak is calculated according to the following.

9. The detection method according to any one of claims 1 to 8, wherein the second scan is a scan along the horizontal direction with respect to at least one pixel, the second scan is performed at a predetermined position, and at least one second scan is performed in the center of the field of view.

10. Substep E4, which is to determine at least one line similarity descriptor, (iii) A substep of determining n tone functions based on a point-to-point comparison between the tone value of the second scan, which is determined by scanning at least one row of pixels having a height of at least one pixel, in the center of the field of view, and the tone value of at least one other second scan, (iv) A substep in which the value of the line similarity descriptor is determined based on the grayscale function determined previously. A detection method according to any one of claims 1 to 9, including the method described in any one of claims 1 to 9.

11. The detection method according to any one of claims 1 to 10, wherein step F includes a substep F1 for normalizing the overall descriptor and the line similarity descriptor.

12. Step F then processes the normalized whole descriptor and the normalized line similarity descriptor as follows: Visible pattern likelihood index = Normalized line similarity descriptor / 2 + Normalized overall descriptor / 2 The detection method according to claim 11, further comprising a substep F2 for averaging as shown.

13. A system (100) for in vitro detection and / or quantification of at least one analyte in a biological sample, a. A support (110) that is at least partially transparent or translucent, having at least one well (111) configured to hold a liquid, b. Apparatus (120), A base (121) configured to accept at least one support (110), One control unit (122), and An imager (123) having a field of view, controlled by the control unit, and configured to acquire an image of at least one well of the support. The apparatus (120) is equipped with Equipped with, The system (100) is characterized in that it includes at least one linear section (131) and at least one pattern (130) intended to at least partially overlap with the liquid, the imager is configured to acquire at least one image of the field of view, and the control unit is configured to determine the presence of the liquid in the well based on the at least one image acquired by the imager in accordance with the detection method of claims 1 to 12.

14. The system according to claim 13, wherein the pattern (130) is etched directly onto the base (121) of the apparatus (120).

15. The system according to any one of claims 13 or 14, wherein the imager (123) is configured to acquire and decode an identification code (114) of the support (110) when it is framed within the field of view, and the imager is configured to transmit the decoded identification code (114) to the control unit.

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