JP2006276003A - Dispensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable accurate detection of the suction amount of liquid sucked by a dispensing nozzle, at all times. <P>SOLUTION: This dispensing device sucks liquid L with a suction section (chip) 12 of the dispensing nozzle, and then discharges and dispenses the liquid. The dispensing device comprises a CCD camera 14 for imaging the suction section 12 having sucked the liquid at a predetermined position, an image processing section 26 for detecting the edges from the imaged and inputted image, and a liquid level state determining section 28 for determining the normality/abnormality of the suction amount of the liquid, based on the lower edge and upper edge detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dispensing apparatus, and more particularly to a dispensing apparatus that is suitable for application in improving inspection accuracy by preventing occurrence of problems such as excess or deficiency in the amount of liquid dispensed.

  Conventionally, a dispensing apparatus has been used for testing liquid specimens. This dispensing apparatus is required to accurately dispense a predetermined amount of specimen or chemical solution in order to realize a highly accurate test. At that time, a dispensing nozzle having a suction part for sucking liquid from the container is generally used.

  In a dispensing apparatus that dispenses liquid using such a dispensing nozzle, as a function for checking a dispensing amount (aspiration amount), for example, Patent Document 1 discloses a pressure sensor installed in the dispensing nozzle and a calculation function. After detecting contact with the liquid from the pressure change when the suction part is lowered from above to the liquid surface, the target suction amount calculated in advance by moving the syringe a predetermined length A method is disclosed.

  Patent Document 2 discloses a method of dispensing a predetermined amount of liquid by performing a suction operation after detecting contact between the probe (suction unit) and the liquid level in the container based on a change in capacitance. ing.

  Further, Patent Document 3 is provided with a fluid sensor for optically identifying the type of fluid that passes through the pipe, and based on the output signal of the fluid sensor, the passing amount of the sensor installation location is integrated and analyzed to produce a dispensing amount and a suction amount. What has the calculating means which calculates | requires quantity is disclosed.

JP 2004-20320 A JP 2003-90754 A JP 2002-303633 A

  However, since all of the dispensing devices disclosed in the above-mentioned patent documents are indirect detection for obtaining the suction amount by calculation based on the detection value by the sensor, there are variations in detection by the sensor, a decrease in accuracy, and the like. However, there was a problem that it was not possible to detect the excess or deficiency of the suction amount due to it.

  The present invention has been made in order to solve the above-described conventional problems, and is capable of always accurately detecting the amount of liquid sucked by the dispensing nozzle regardless of the detection accuracy of the sensor or the like. It is an object to provide an apparatus.

  The present invention relates to a dispensing apparatus that sucks a liquid by a suction part of a dispensing nozzle and then discharges and dispenses the liquid, and an imaging unit that images the suction part that sucked the liquid at a predetermined position. The above-mentioned problem has been solved by providing edge detection means for detecting an edge from an input image and suction amount determination means for determining whether the liquid suction amount is normal or abnormal from the detected lower edge and upper edge. Is.

  The present invention also includes an edge counting unit that searches the image of the suction portion where the edge is detected by the edge detecting unit in the vertical direction and counts the edge, and a correct liquid suction state based on the counted number of edges. You may make it provide the state determination means which determines abnormality.

  The present invention further includes an inclination detection unit that detects an inclination angle of the suction unit from an image of the suction unit imaged by the imaging unit, and the lower edge and the upper edge in consideration of the detected inclination angle. An edge-to-edge calculation means for calculating the length between the edges may be provided.

  According to the present invention, the suction unit that sucks the liquid is imaged by the imaging unit, the sucked liquid is input as an image, an edge is detected from the input image, and the difference between the detected lower edge and upper edge is detected. Since the suction amount is detected, it is possible to directly detect the suction amount of the liquid. In addition, variations in the height direction when the suction part is attached and stop errors at the imaging position can be omitted.

  FIG. 1 is a schematic side view including a block diagram schematically showing a main part of the dispensing apparatus according to the first embodiment of the present invention.

  The dispensing device of the present embodiment includes a dispensing head unit 10. The dispensing head unit 10 is provided with a tip (suction part) 12 at the tip thereof, and the inside of the tip 12 has a negative pressure, and a plurality of dispensing nozzles (not explicitly shown) that can move up and down integrally are incorporated. As shown in FIG. 2, eight chips can suck the liquid L such as the sample in each chip 12 at a predetermined position (not shown).

  The dispensing head unit 10 has a CCD camera (imaging means) 14 attached to the side surface thereof, and the chip 12 positioned at the illustrated position by the camera 14 is illuminated by a backlight 16. Thus, the image can be captured by being reflected by the inclined mirror 18.

  In addition, the dispensing device of the present embodiment includes a calculation unit 20, and the calculation unit 20 captures an image with the imaging timing generation unit 22 that outputs a timing signal to be captured by the CCD camera 14 and the camera 14. A backlight lighting unit 24 that turns on the backlight 16 at the time, an image processing unit 26 that functions as an edge detection unit that detects an edge from image data captured and input by the camera 14, and among the detected edges The liquid surface state determination unit 28 that functions as a total amount determination unit that determines the amount of liquid suction from the difference between the lower end edge and the upper end edge and determines its normal / abnormality in comparison with a preset reference amount, and the determination result And an alarm determination unit 30 for determining whether or not to output an alarm, and an alarm is displayed based on a result of the determination by the alarm determination unit 30. It has become.

  The image processing unit 26 also functions as an edge counting unit that searches the image of the suction unit in which an edge is detected in the vertical direction and counts the edges, and the liquid level state determination unit 28 counts. It also functions as state determination means for determining whether the suction state is normal or abnormal from the number of edges.

  Next, the operation of this embodiment will be described.

  First, the chip 12 that has sucked liquid from a container (not shown) at a predetermined position is positioned at the imaging position shown in FIG.

  The backlight illumination 16 is turned on at the timing controlled by the imaging timing generation unit 22 at the same time as the positioning is completed (step 1), and the electronic shutter of the CCD camera 14 is similarly controlled at the timing controlled by the imaging timing generation unit 22. (Step 2). Note that optical conditions such as illumination brightness and shutter speed are adjusted in advance so as to obtain an image suitable for the following processing.

  An image is captured from the CCD camera 14 into the processing unit 26 in accordance with a capture signal from the image processing unit 26 output in conjunction with the shutter operation to the CCD camera 14.

  In the image processing unit 26, the position of each chip is detected by pattern matching with the chip shape stored in advance for each chip in the captured image (step 4).

  Specifically, the input image is processed by a differential filter or the like, and the boundary between the tip 12 and the sucked liquid L is extracted as an edge by extracting a position where the pixel value differs by a predetermined value or more as a boundary. An edge extraction image as shown in FIG. 2 is created, and pattern matching is performed on each extracted chip. Based on the position detection result, the position of each chip on the image can be corrected and the presence / absence of the chip 12 can also be inspected.

  Next, for the edge extracted image, the target chip to be subjected to image inspection processing is set to n, and n = 1 (step 5). For example, as shown in FIG.

  For the nth chip shape detected in step 4, the bottom edge of the Y coordinate is detected. That is, as shown in the image on the XY coordinate for one chip in FIG. 5, the Y coordinate of the tip (lower edge) is detected and stored as Y0, and the edge number counter for this nth chip is set to 0. (Step 6).

  An edge search is performed in the Y direction from the Y coordinate of the tip of the chip detected in step 6 for the edge extracted image (step 7). If an edge is detected, the process proceeds to step 9; if an edge is not detected, the process proceeds to step 10 (step 8).

  In step 9, the edge counter is incremented by 1, and the Y coordinate (Y1 or Y2 in the example of FIG. 5) of the pth edge from the bottom is stored.

  In the next step 10, it is determined whether or not the search up to a preset upper end is completed. If completed, the process proceeds to step 11, and if not completed, the process returns to step 7 to continue the edge search.

  It is determined whether or not the above edge detection processing has been completed for all the chips (step 11). If completed, the process proceeds to step 13. If not completed, the next step 12 determines the chip number to be inspected. +1 and return to step 6 to perform the same edge detection for the next chip. By repeating the above operation, the detection of the number of edges and the Y coordinate of all chips is completed.

  Then, for each chip, (Y coordinate of the lower edge) − (Y coordinate of the upper edge) is calculated (step 13), and the obtained value (length) is compared with a reference value, and the difference is an allowable value. It is determined whether or not (the number of pixels) or less (step 14).

  As a result of the determination, if it is within the allowable value, it is determined whether or not the number of edges is only one on the surface of the liquid for each chip. That is, for example, if there is a bubble at the tip, there is a first edge indicated by Y1 in addition to the second edge Y2 of the liquid surface shown in FIG. Will be.

  In the case where the number is not within the allowable value in the step 14, for example, the number 4 or the number 6 chip shown in FIG. In the alarm determination unit 30, an alarm is displayed on the display unit (step 16). It should be noted that within one of the steps 15 includes a case where the number of edges is 0 because the chip is empty and no liquid surface exists.

  According to the present embodiment described in detail above, when the actual suction amount is excessive or insufficient for some reason with respect to the set suction amount reference value, the fact is detected before dispensing. Can inform the operator. Therefore, in the inspection process performed thereafter, it is possible to effectively prevent the occurrence of problems such as abnormal reaction between the specimen and the medicine due to excessive or insufficient dispensing amounts.

  FIG. 6 is a schematic side view corresponding to FIG. 1 and showing an outline of the dispensing apparatus according to the second embodiment of the present invention.

  The dispensing apparatus of the present embodiment is substantially the same as in the case of the first embodiment except that the image processing unit 26 is configured as described later. Detailed description is omitted.

  In the image processing unit 26 of the present embodiment, the chip (suction unit) is arranged by applying pattern matching to the edge extraction image created from the image captured by the CCD camera (imaging means) as in the first embodiment. In consideration of the detected inclination angle, the pattern matching processing section 26A for specifying the shape including the position, the chip inclination detecting section 26B for detecting the inclination angle by comparing the arrangement shape of the specified chip with the reference shape, An edge detection processing unit (edge-to-edge calculation unit) 26C that detects the lower and upper edges corresponding to the liquid level and calculates the length between the edges is included.

  In a normal dispensing operation, a disposable tip (disposable tip) is attached to the dispensing nozzle. At this time, it is desirable that the chip is connected to the nozzle in the vertical direction, but it may be mounted in an inclined state. In this case, the search is performed only in the Y direction as in the first embodiment. Depending on the image processing, there may be a problem in the stability and accuracy of edge detection corresponding to the liquid level. This problem also occurs when the tip is tilted by touching a sample or the like from a plate or test tube containing liquid during the dispensing operation.

  That is, FIG. 7 shows an image of an edge extraction image of a normal chip mounted on a nozzle straight in the vertical direction. In this case, as in the image processing of the first embodiment, edge detection can be accurately performed by performing an edge search straight in the Y direction.

  However, when the tip is tilted as shown in FIG. 8, the edge search accuracy straight in the Y direction has a problem in the edge detection accuracy of the liquid level, and even in the worst case even the edge detection is performed. There is also a fear that it cannot be done.

  Therefore, in the present embodiment, even when the tip is tilted as described above, the image processing unit 26 performs the following processing so that edge detection can be reliably performed by image processing to determine whether the liquid amount is normal or abnormal. Perform the following process.

  In FIG. 9, the image of the registered image of the reference chip is indicated by a broken line. This is an image corresponding to FIG. 7 taken with the chip mounted straight, and is registered in advance in a memory (not shown) in the image processing unit 26. In the figure, an image of an image obtained by actually capturing the tilted chip is shown by a solid line in comparison with a registered image.

  In this embodiment, in the pattern matching processing unit 26A of the image processing unit 26, the two images are compared by a known pattern matching technique related to the chip outer shape. Specifically, the chip inclination detection unit 26B calculates center lines indicated by alternate long and short dash lines for the edge extracted image corresponding to the outer shape of the chip obtained from the shaded portion of each image, and calculates the difference between the two inclinations. . As a result, it is possible to obtain the inclination difference θ between the registered image and the actually captured image as illustrated.

  When the tilt angle θ is detected between the reference registered image and the captured image as described above, the edge detection processing unit 26C thereafter performs the edge search in the vertical direction as shown in FIG. Tilt from θ to θ. In other words, the edge of the captured image of the chip is searched from the bottom to the top along the center line. From the tip tip position coordinates (X0, Y0) and the liquid surface position coordinates (X1, Y1) obtained as edges, the tip surface (lower edge) to the liquid surface (upper edge) by, for example, the square theorem. It is possible to measure the exact distance (length) up to.

  By performing the image processing as described above, it is possible to cope with the worst case that the edge θ cannot be detected by the method of the first embodiment because the inclination θ is large. However, it is needless to say that when the inclination θ is large, an alarm such as a tip mounting abnormality can be generated to notify the operator.

  According to this embodiment described above in detail, even when the tip is tilted, accurate liquid level detection is possible, and it is possible to reliably determine whether the liquid suction amount is normal or abnormal.

  In addition, when the tip tilt is large, an alarm or the like can be generated to notify the operator of the occurrence of an abnormality.

  In the above-described embodiment, the CCD camera is shown as the imaging unit. However, the present invention is not limited to this, and a CMOS camera may be used. The specific configuration of the imaging system is not limited to that shown in the embodiment.

The schematic side view including the block diagram which shows the principal part of the dispensing apparatus of 1st Embodiment which concerns on this invention Schematic diagram showing the chip attached to the lower end of multiple suction nozzles Flow chart showing the operation of the embodiment Flowchart showing continued operation of embodiment Explanatory drawing which shows typically XY image of the chip which inputted the image The schematic side view including the block diagram which shows the principal part of the dispensing apparatus of 2nd Embodiment which concerns on this invention Explanatory drawing showing the state of normal chip edge detection Explanatory drawing which shows the problem in the case of detecting an edge of an inclined tip Explanatory drawing showing an image of the tip tilt angle detection method Explanatory drawing which shows the edge search method with respect to the inclination chip | tip of 2nd Embodiment.

Explanation of symbols

10: Dispensing head unit 12 ... Tip (suction part)
14 ... CCD camera (imaging means)
DESCRIPTION OF SYMBOLS 16 ... Backlight 18 ... Inclination mirror 26 ... Image processing part 26A ... Pattern matching process part 26B ... Chip inclination detection part 26C ... Edge detection processing part 28 ... Liquid level state determination part L ... Liquid

Claims (3)

In a dispensing device that dispenses by discharging the liquid after the liquid is sucked by the suction part of the dispensing nozzle,
Imaging means for imaging the suction part that sucked the liquid at a predetermined position;
Edge detection means for detecting an edge from an image captured and input;
A dispensing apparatus comprising: a suction amount determination means for determining whether the suction amount of the liquid is normal or abnormal from the detected lower edge and upper edge. Edge counting means for searching the image of the suction part from which the edge is detected by the edge detection means in the vertical direction and counting the edges;
The dispensing apparatus according to claim 1, further comprising a state determination unit that determines whether the liquid suction state is normal or abnormal from the counted number of edges. Inclination detection means for detecting the inclination angle of the suction part from the image of the suction part imaged by the imaging means;
The dispensing apparatus according to claim 1, further comprising an inter-edge calculation unit that calculates a length between the lower edge and the upper edge in consideration of the detected inclination angle.

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