Test paper imaging device

Abstract

To provide a test paper imaging device with which it is possible to suppress an increase in the arithmetic load of image processing and prevent the device size from becoming large, as well as reduce influences by limb darkening.SOLUTION: An imaging device 30 comprises: an imaging chamber 31 composed of an imaging surface 31da, an upper wall 31a, and peripheral walls 31b, 31c enclosing the imaging surface 31da; a camera 32 installed in the middle of the upper wall 31a; and an illumination unit 33 installed to the upper wall 31a, for irradiating illumination light from a planar light-emitting unit 33a. The light-emitting unit 33a is provided in a region away from an optical axis L32 due to the fact that a non-light-emitting unit 34 is formed around the optical axis L32 of the camera 32. Inner wall surfaces A of peripheral walls 31b, 31c constitute a reflection plane composed of white material. The luminous energy of indirect illumination light irradiated from the light-emitting unit 33a to the imaging surface 31da after being reflected by the inner wall surface A is greater than the luminous energy of direct illumination light irradiated directly to the imaging surface 31da from the light-emitting unit 33a.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a test strip imaging device. [Background technology]

[0002] In urine testing devices and the like, a test strip imaging device that images a long and thin test strip (also called a test strip, etc.) with a sample spotted on a reagent is sometimes used. On the other hand, as described in Patent Document 1, for example, there is also a method of imaging a test strip using a general-purpose digital camera, etc., without using such a dedicated device. In the system described in Patent Document 1, a correction formula is presented for correcting luminance unevenness in the captured image acquired by the digital camera.

[0003] In addition, the test strip analyzer described in Patent Document 2 uses a straight fluorescent lamp as the light source. Variation correction is performed for the light intensity distribution in the longitudinal direction of the test strip. In this variation correction, the test strip is irradiated with a light source having a length three times that of the reagent layer of the test strip, and brightness correction is performed using a standard reflector placed in the center of the photometer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-95328 A [Patent Document 2] Japanese Patent Application Publication No. 10-31011 Summary of the Invention [Problem to be solved by the invention]

[0005] When capturing an image of a long and narrow test paper placed on the imaging surface, the distance from the camera to each part of the test paper (usually, multiple reagent parts are arranged on the test paper) that is the object to be captured is not constant. In other words, the distance varies depending on the reagent part. Under this premise, the edge of the imaging surface may become dark in the captured image due to the effect of peripheral light reduction. As a result, the concentration, etc. is not accurately reflected, which affects the measurement result.

[0006] In order to correct the effect of vignetting, correction such as the above-mentioned conventional technology is considered. However, in the system described in Patent Document 1, it is necessary to correct the brightness unevenness during image processing, so the calculation load in image processing tends to be high. In addition, in the device described in Patent Document 2, it is necessary to use a large (long) light source, which increases the size of the entire device.

[0007] The present disclosure describes a test strip imaging device that can reduce the effects of vignetting, suppress an increase in the computational load in image processing, and prevent the device from becoming large. [Means for solving the problem]

[0008] [1] One aspect of the present disclosure is a test paper imaging device that images a test paper of an elongated shape placed on an imaging surface, the device comprising: an imaging chamber including an imaging surface, an opposing wall portion facing the imaging surface, and a peripheral wall portion extending in a direction intersecting the imaging surface and the opposing wall portion and surrounding the imaging surface; a camera installed in the center of the opposing wall portion; and an illumination portion installed in the opposing wall portion and irradiating illumination light from a planar light-emitting portion toward the imaging surface and an inner wall surface of the peripheral wall portion, the light-emitting portion of the illumination portion being provided in an area spaced from the optical axis of the camera by forming a non-light-emitting portion around the optical axis of the camera, the inner wall surface of the peripheral wall portion being a reflective surface made of a white material, and of the amount of illumination light illuminating the imaging surface, the amount of indirect illumination light reflected from the light-emitting portion by the inner wall surface and irradiated onto the imaging surface is greater than the amount of direct illumination light directly irradiated from the light-emitting portion to the imaging surface.

[0009] According to the test strip imaging device of [1], a non-light emitting portion is formed around the optical axis of the camera in the facing wall. The planar light emitting portion is provided in an area spaced apart from the optical axis of the camera. In addition to this configuration, the inner wall surface of the peripheral wall is a reflective surface made of a white material. In this test strip imaging device, in addition to these configurations, the amount of indirect illumination light is greater than the amount of direct illumination light. The ratio of illumination light is defined based on the respective amounts of light. The large amount of indirect illumination light reduces the effect of peripheral darkening at the end of the imaging surface relatively close to the inner wall surface. According to this test strip imaging device, the brightness of the captured image is made uniform, so that complicated corrections in image processing are not required. In addition, since the reflection of light by the reflective surface (inner wall surface) made of a white material is utilized, there is no need to enlarge the light emitting portion.

[0010] [2] In the test strip imaging device described in [1] above, the amount of indirect illumination light may be 60% or more of the amount of illumination light illuminating the imaging surface. In this case, since the amount of illumination light (indirect illumination light) passing through the inner wall surface is large, the effect of peripheral light falloff can be more effectively reduced.

[0011] [3] In the test strip imaging device described in [1] or [2] above, the ratio of the area where the light emitting unit is provided to the total area of ​​the area of ​​the facing wall facing the inside of the imaging chamber may be 53% or less. In this case, the area of ​​the light emitting unit in the area away from the optical axis of the camera is optimized, and the effect of peripheral darkening can be more effectively reduced. Effect of the Invention

[0012] According to the present disclosure, it is possible to reduce the effects of vignetting, and also to suppress an increase in the computational load in image processing and prevent an increase in the size of the device. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a urine test apparatus to which a test strip imaging device according to an embodiment of the present disclosure is applied. [Diagram 2] FIG. 2 is a front view showing a schematic configuration of the inside of the main body of the apparatus shown in FIG. [Diagram 3] FIG. 3 is a perspective cross-sectional view showing the first and second transport mechanisms, the spotting device, the imaging device, and the waste box in the device main body. [Figure 4] FIG. 4 is a perspective cross-sectional view of the test strip imaging device. [Diagram 5] FIG. 5 is a block diagram showing the configuration of the test strip imaging device and the inspection section. [Figure 6] FIG. 6 is an exploded perspective view of the test strip imaging device. [Figure 7] FIG. 7(a) is a vertical cross-sectional view of the test strip imaging device, and FIG. 7(b) is a bottom view of the imaging chamber. [Figure 8] FIG. 8(a) is a vertical cross-sectional view of the test strip imaging device according to the embodiment, and FIG. 8(b) is a diagram showing the light amount distribution (simulation result) of illumination light based on the device of FIG. 8(a). [Figure 9] FIG. 9(a) is a vertical cross-sectional view of a test strip imaging device according to a reference embodiment, and FIG. 9(b) is a diagram showing the light amount distribution (simulation result) of illumination light based on the device of FIG. 9(a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same elements are given the same reference numerals, and duplicated explanations will be omitted. The dimensional ratios of the drawings do not necessarily match those in the description.

[0015] In some figures, mutually orthogonal X, Y and Z directions are shown, and these directions may be used to explain the urine testing apparatus 1. The X, Y and Z directions correspond to the left-right direction, the front-back direction and the up-down direction in the installed state of the urine testing apparatus 1 shown in Figures 1 and 2, respectively. In this specification, terms indicating directions such as "front", "back", "up", "down", "left" and "right" are terms based on the installed state of the urine testing apparatus 1. The urine testing apparatus 1 is installed on a flat and horizontal surface. "Left" and "right" are the directions when the urine testing apparatus 1 is viewed from an operator standing in front of the mounting table 3 and the display 5b and facing the mounting table 3 and the display 5b.

[0016] First, the overall configuration of the urine testing apparatus 1 will be described with reference to Figs. 1 and 2. The urine testing apparatus 1 is an apparatus for testing urine as a specimen contained in a spigot 100. As shown in Fig. 1, the urine testing apparatus 1 sequentially tests each specimen in a plurality of spigots 100 standing on a rack R. The test items (test purposes) are not particularly limited. Examples of the test items include the physical properties of the specimen, or the presence or concentration of a specific component in the specimen. In the urine testing apparatus 1, a test paper C having an elongated shape is used to test the specimen (see Fig. 3). One test paper C is used for one specimen. Each test paper C is provided with, for example, a plurality of reagent portions Ca. Each reagent portion Ca may correspond to a different test item. Each reagent portion Ca contains a reagent corresponding to the test item. A known configuration may be appropriately adopted for the test paper C.

[0017] As shown in Fig. 1, the urine testing apparatus 1 comprises an apparatus main body 2 which houses various devices and mechanisms related to the transport of test papers C and the testing of samples, and a mounting base 3 which has a transport mechanism and the like related to the supply and transport of racks R. The apparatus main body 2 comprises a lower apparatus part 4 and an upper apparatus part 5 which is disposed on a part of the lower apparatus part 4 in the left-right direction (e.g., the left side). The mounting base 3 is coupled to the front surface of the lower apparatus part 4. The urine testing apparatus 1 further comprises a supply mechanism 40 which is a mechanism related to the storage of test papers C and the supply of test papers C to the apparatus main body 2. The supply mechanism 40 is disposed on another part of the lower apparatus part 4 in the left-right direction (e.g., the right side).

[0018] As shown in FIG. 2, the device body 2 has a frame F made of structural members extending in the up-down, left-right, and front-rear directions. As shown in FIG. 1, the device lower part 4 includes a lower housing 4a, and the device upper part 5 includes an upper housing 5a. The lower housing 4a and the upper housing 5a are shaped like a rectangular parallelepiped based on the shape of the frame F. A front panel 5c is provided on the front surface of the upper housing 5a, which can be opened and closed by rotating, for example, around an axis L5 extending in the up-down direction (Z direction). A display 5b is provided on the upper part of the front panel 5c. The display 5b is directed forward, and displays necessary information related to the test to the operator of the urine testing device 1. The display 5b may have a touch panel function. In that case, the display 5b can also serve as an operation unit operated by the operator.

[0019] The mounting table 3 has a width in the left-right direction that is approximately equal to that of the device body 2. The mounting table 3 also has a predetermined size in a plan view. A plurality of racks R can be mounted on the mounting table 3. Although only one rack R is shown in FIG. 1, a plurality of racks R can be mounted on the right and left sides of the mounting table 3. The mounting table 3 is provided with a transport mechanism (not shown) that transports the rack R in a required direction. A known configuration can be adopted as a specific configuration of the transport mechanism. As an example, the devices (structures) described in JP-A-10-120167 and JP-A-10-139152 may be applied. Note that both or either one of the first rack transport mechanism 6 and the second rack transport mechanism 7 may be omitted.

[0020] Returning to Fig. 2, the device main body 2 is provided with a controller 90, for example, in the upper housing 5a. The controller 90 is a computer having, for example, a storage medium such as a ROM (Read Only Memory) in which programs and the like are stored, a RAM (Random Access Memory) for temporarily storing data, and a processor such as a CPU (Central Processing Unit). The controller 90 controls the operation of the mechanisms and devices in the urine testing apparatus 1 according to a program stored in advance in response to an operation by an operator, thereby performing various operations related to the test. The controller 90 is capable of communicating information with various motors and centers provided in the supply mechanism 40, the first transport mechanism 10, and the second transport mechanism 20, the camera 32, the lighting unit 33, and the like of the imaging device 30.

[0021] As shown in Figs. 1 and 2, the supply mechanism 40 is a feeder for supplying the test papers C one by one in a predetermined orientation (posture). The supply mechanism 40 has a rectangular parallelepiped housing 40a, a casing 43 arranged inside the housing 40a, and a pair of input lids 41 that can be opened and closed relative to the casing 43. The supply mechanism 40 accommodates a plurality of test papers C input by an operator through the input lid 41. The plurality of test papers C are input with their longitudinal orientations aligned (in the orientation shown in Fig. 3) so that the portion in which the plurality of reagent portions Ca (see Fig. 3) are arranged at regular intervals is positioned forward. The supply mechanism 40 sequentially discharges the test papers C one by one from the discharge portion 49. A sensor (not shown) is provided inside the supply mechanism 40 for detecting that one test paper C has been successfully removed. When the controller 90 detects the planned supply of test papers C (the planned discharge of test papers C from the discharge section 49), it controls the first transport mechanism 10 (see FIG. 3) described later to move the arm 11 to directly below the discharge section 49 at a predetermined timing. The test papers C that fall from the discharge section 49 are placed on the support portion 11a of the arm 11. This causes the supply mechanism 40 to sequentially supply the test papers C one by one to the first transport mechanism 10.

[0022] In this embodiment, the supply mechanism 40 includes a pair of insertion lids 41 and is capable of supplying two (or multiple) types of test papers C. This is merely one example, and the supply mechanism 40 may be of a type capable of supplying only one type of test papers C.

[0023] Next, various components of the device body 2 will be described with reference to Figures 2 and 3. The device body 2 includes a first transport mechanism 10 that transports the test paper C received from the supply mechanism 40 to the spotting position Pa or its vicinity, a spotting device 9 that spots a sample on each reagent portion Ca of the test paper C placed at the spotting position Pa, a second transport mechanism 20 that transports the test paper C from the spotting position Pa to an imaging position Pb, and an imaging device (test paper imaging device) 30 that images the test paper C placed at the imaging position Pb. In other words, the device body 2 spots the sample on the test paper C and analyzes a specific component in the sample.

[0024] The device body 2 further includes a waste box 60 for storing the test papers C that have been discharged from the imaging device 30 after image capture by the imaging device 30. The rectangular waste box 60 is open toward the top and is capable of storing a large number (a certain number) of test papers C in an internal storage space 65. In this embodiment, an internal space S (see FIG. 1) having a size (volume) equal to or larger than that of the waste box 60 is formed below the waste box 60.

[0025] As shown in FIG. 3, the first transport mechanism 10 includes, for example, an arm 11 that supports the test paper C by a support portion 11a, a moving block 13 to which the arm 11 is fixed, and a pair of shafts 12 that extend in the X direction (horizontal direction) and guide the moving block 13 in that direction. The first transport mechanism 10 also includes a drive motor controlled by a controller 90, a pair of pulleys, a timing belt stretched over the pair of pulleys, and the like (none of which are shown). The moving block 13 is connected to the timing belt. The first transport mechanism 10 moves the arm 11 to directly below the discharge portion 49 at the above-mentioned predetermined timing. The first transport mechanism 10 receives one test paper C from the supply mechanism 40, and then transports the test paper C to a predetermined position above the spotting position Pa where the sample is applied. That is, in this embodiment, the first transport mechanism 10 transports the test paper C received from the supply mechanism 40 to the vicinity of the spotting position Pa.

[0026] The rear end of the test paper C transported above the spot application position Pa is aligned forward by a push-out plate 15A which is movable in the front-rear direction. The rotational driving force of the push-out motor 15B is converted into a linear force by a crank mechanism (not shown), thereby adjusting the movement of the push-out plate 15A. Other known configurations may be appropriately adopted as the mechanism for driving the push-out plate 15A.

[0027] The first transport mechanism 10 is not limited to the above configuration. The first transport mechanism 10 may transport the test paper C received from the supply mechanism 40 to the spot application position Pa. The first transport mechanism 10 may be any mechanism capable of receiving the test paper C from the supply mechanism 40 and transporting it laterally. Other known configurations may be adopted for the first transport mechanism 10. For example, the first transport mechanism 10 may include a belt conveyor or the like. The first transport mechanism 10 may include a slide rail or a linear guide or the like.

[0028] As shown in FIG. 2 and FIG. 3, the spotting device 9 collects (samples) a predetermined amount of the specimen in the spigot 100 and spots the specimen on each reagent portion Ca of the test paper C placed at the spotting position Pa. The spotting device 9 includes a support drive mechanism 9c and a rail 9b arranged in the upper housing 5a, and a nozzle 9a that can move in the vertical direction (Z direction) and the front-back direction (Y direction) along the rail 9b. The support drive mechanism 9c includes a drive motor (not shown). When the controller 90 detects that the spigot 100 arrives at a predetermined position in front of the spotting device 9 (in front of the spotting position Pa), the controller 90 controls the spotting device 9, and the specimen is collected by the nozzle 9a. When the nozzle 9a moves forward, it reaches a position protruding from the device body 2 (i.e., the area of ​​the mounting base 3). That is, the nozzle 9a is movable between the device body 2 and the mounting base 3. When collecting a sample, the pump unit PU arranged in the upper housing 5a is also controlled by the controller 90 and operates in conjunction with the spotting device 9.

[0029] The spotting position Pa is set at a position slightly higher than the upper end of the spit 100 on the rack R. This minimizes the vertical stroke of the nozzle 9a. That is, the tip 9t of the nozzle 9a needs to enter the spit 100 to a predetermined depth, but after the specimen is collected, the tip 9t leaves the spit 100 and moves backward at a position slightly higher than the upper end. After that, spotting is performed on each reagent part Ca, for example, starting from the rear reagent part Ca. The spotting device 9 repeats the same operation every time a new specimen (spit 100) arrives at the predetermined position. Although not shown, the spotting device 9 has a cleaning part or the like for cleaning the nozzle 9a between the spotting position Pa and the spit 100.

[0030] As shown in Figs. 2 and 3, the second transport mechanism 20 is, for example, a mechanism for transporting a plurality of test papers C in a step-like manner with a predetermined pitch. In this embodiment, the imaging position Pb is located to the left of and higher than the spotting position Pa. The second transport mechanism 20 transports the test papers C diagonally upward. The second transport mechanism 20 includes, for example, a pair of outer fixed plates 21, one central fixed plate 22 disposed at a middle position in the front-rear direction between the pair of outer fixed plates 21, and a pair of movable plates 23 disposed between the pair of outer fixed plates 21 and the central fixed plate 22 (since Fig. 3 is a cross-sectional view, the front outer fixed plate 21 is not shown). The outer fixed plate 21, the central fixed plate 22, and the movable plate 23 are each disposed parallel to the XZ plane and have a substantially congruent step shape. In the outer fixed plate 21, the central fixed plate 22, and the movable plate 23, the pitches (height difference and left-right distance) of all horizontal steps are set to be equal.

[0031] The pair of movable plates 23 are moved in a predetermined circular orbit by a drive motor and a rectangular cam (not shown). More specifically, the pair of movable plates 23 move in a substantially rectangular orbit (counterclockwise orbit as viewed from the front) between two adjacent horizontal steps of the outer fixed plate 21 and the central fixed plate 22. As a result, the second transport mechanism 20 transports each test paper C placed on a horizontal step to the next higher horizontal step, and repeats this operation.

[0032] The test paper C transported above the spotting position Pa by the first transport mechanism 10 is transferred from the arm 11 of the first transport mechanism 10 to the spotting position Pa by the operation of the movable plate 23. That is, the test paper C transported to the transfer position is lifted upward from the arm 11 by the movable plate 23. At that time, the arm 11 moves to directly below the discharge section 49 (to transport the next test paper C). The test paper C lifted upward draws a substantially rectangular orbit (a clockwise orbit when viewed from the front) and is placed on the lowest horizontal step of the outer fixed plate 21 and the central fixed plate 22, which is the spotting position Pa. The highest horizontal step of the outer fixed plate 21 and the central fixed plate 22 is disposed inside the imaging device 30 and is the imaging position Pb. The second transport mechanism 20 transports the test paper by taking into account the time required for the color development of the reagent portion Ca.

[0033] The second transport mechanism 20 is not limited to the above configuration. The second transport mechanism 20 may be any mechanism capable of transporting the test paper C placed at the application position Pa diagonally upward. Other known configurations may be adopted for the second transport mechanism 20. For example, the second transport mechanism 20 may include a belt conveyor or the like. The second transport mechanism 20 may also be capable of transporting the test paper C in a horizontal direction, such as to the left. In this case, the imaging position Pb may be at the same height as the application position Pa.

[0034] As shown in FIG. 1, the imaging device 30 includes a rectangular parallelepiped (or cubic) imaging chamber 31 arranged to surround an imaging position Pb, a camera 32 arranged on the upper surface of the imaging chamber 31, and an illumination unit 33 arranged around the camera 32 on the upper surface of the imaging chamber 31. The imaging device 30 reads optical information of the test strip C on which a sample has been dropped. The imaging position Pb is located at the approximate center of the imaging chamber 31, at the bottom of the imaging chamber 31. The test strip C maintains a posture in which its longitudinal direction is always oriented in the front-rear direction (perpendicular to the paper surface of FIG. 1) and the reagent portion Ca is oriented upward, from when it is supported by the arm 11 of the first transport mechanism 10 until it is transported by the second transport mechanism 20 and reaches the imaging position Pb. The camera 32 captures an image of the entire test strip C and transmits the image information to the controller 90.

[0035] The controller 90 performs testing, i.e., measurement and judgment, for each test item based on the image of the test strip C acquired by the imaging device 30. The controller 90 displays the measurement results and judgment results on the display 5b together with unique information such as the sample ID. The controller 90 also stores the measurement results and judgment results together with unique information such as the sample ID in the memory unit. The controller 90 has the function of a testing unit in the urine testing apparatus 1.

[0036] After the image of the test piece C has been captured by the imaging device 30 , the test piece C is discharged from the imaging device 30 by the second transport mechanism 20 and placed in a waste box 60 .

[0037] Next, the imaging device 30 will be described in more detail with reference to Figs. 4 to 7(a) and 7(b). As shown in Figs. 4 and 6, the imaging device 30 captures an image of a test paper C placed at an imaging position Pb. The imaging device 30 has an imaging surface 31da including the imaging position Pb, and a rectangular parallelepiped box provided to cover the imaging surface 31da. The box includes an upper wall portion (opposing wall portion) 31a facing the imaging surface 31da, and a pair of first side walls (peripheral wall portions) 31b and a pair of second side walls (peripheral wall portions) 31c extending in a direction intersecting the imaging surface 31da and the upper wall portion 31a. A horizontal flat bottom wall portion 31d is provided at the same height as the uppermost horizontal step portions of the outer fixing plate 21 and the central fixing plate 22. The bottom wall portion 31d is disposed at the bottom of the box, and its surface (upper surface) is the imaging surface 31da. The upper wall 31a faces the imaging surface 31da in the up-down direction. The pair of first side walls 31b face each other in the front-rear direction (Y direction), and the pair of second side walls 31c face each other in the left-right direction (X direction). The imaging chamber 31 is composed of the imaging surface 31da, the upper wall 31a, the pair of first side walls 31b, and the pair of second side walls 31c. The test paper C is transported by the second transport mechanism 20 and placed on the imaging surface 31da with its long dimension facing the front-rear direction.

[0038] The box body is made of, for example, resin, and is molded as a single unit. The inner wall surfaces A (see Figs. 7(a) and 7(b)) of the pair of first side wall portions 31b and the pair of second side wall portions 31c are, for example, diffuse reflection surfaces made of a white material. The surface properties of these four inner wall surfaces A are, for example, uniform (uniform). The inner wall surfaces A are formed, for example, by injection molding using a plastic material. The reflection characteristics of the inner wall surfaces A are general and are classified into regular reflection and diffuse reflection. In addition, in this specification, "white" includes white, but does not mean only white, and also includes other colors. In this specification, "white" includes gray and high reflectance colors.

[0039] As shown in FIG. 4, FIG. 6, and FIG. 7(a), a camera 32, which is an imaging means, is installed in the center of the upper wall 31a. The camera 32 includes a lens portion 32a and an imaging portion 32b. The optical axis L32 of the lens portion 32a is, for example, parallel to the vertical direction (Z direction) and perpendicular to the upper wall portion 31a and the bottom wall portion 31d. A circular insertion hole 31aa is formed in the center of the upper wall portion 31a, and the cylindrical lens portion 32a is inserted into the insertion hole 31aa. The imaging portion 32b includes an imaging element such as a CCD or CMOS. The focal point of the lens portion 32a is configured to match the imaging surface 31da. The lens portion 32a forms an image of the test paper C on the imaging element. Note that the term "center" with respect to the arrangement of the camera should not be interpreted strictly, but means approximately near the center. That is, the optical axis L32 of the lens portion 32a may pass through the center of the upper wall portion 31a, or may be disposed at a position slightly shifted from the center.

[0040] An illumination unit 33 that irradiates illumination light in the imaging room 31 is installed on the upper wall 31a. In this embodiment, the illumination unit 33 has a pair of light source units 33b including, for example, LEDs, and a light emitting unit 33a made of a light guide plate attached to the inner surface of the upper wall 31a. The light source unit 33b is a flat plate-like member extending along the XZ plane. The light source unit 33b is fixed on a pair of step surface units 31g that face each other in the front-rear direction (Y direction) with a distance (distance) smaller than the distance (distance) between the pair of first side wall units 31b. A long and narrow rectangular through hole 31e is formed in the rectangular plate-like step surface unit 31g extending along the XZ plane. The light source unit 33b is provided with a point light source array unit 33ba made of a plurality of point light sources arranged in the left-right direction (X direction). A pair of end faces (end faces corresponding to the four sides forming the outer shape) of the light emitting unit 33a in the front-rear direction (Y direction) face each of the pair of through holes 31e. The light emitted from the point light source array section 33ba through the through hole 31e enters the light emitting section 33a from the pair of opposing surfaces.

[0041] The illumination unit 33 irradiates illumination light from the planar light-emitting unit 33a toward the imaging surface 31da and the four inner wall surfaces A of the first side wall portion 31b and the second side wall portion 31c. The light-emitting unit 33a emits light from a surface.

[0042] Here, referring to FIG. 5, the function of the inspection unit 90A provided in the controller 90 will be described. The controller 90 can control the light source unit 33b, the camera 32, and the second transport mechanism 20. The controller 90 can also input the captured image acquired by the camera 32. When the test paper C is transported to the imaging position Pb, the controller 90 controls the camera 32 and the light source unit 33b to capture the image of the test paper C. At this time, the captured image includes the color development results of the multiple reagent portions Ca. The controller 90 functions as the inspection unit 90A. The inspection unit 90A includes a signal acquisition unit 91 that acquires a signal corresponding to the captured image, an image processing unit 92 that performs a predetermined image processing, a judgment unit 93 that makes a judgment regarding the above-mentioned inspection items based on the result of the image processing, and an output unit 94 that outputs the judgment result (or measurement result) and displays it on the display 5b (and stores it in the memory unit). The judgment unit 93 cuts out the image portion corresponding to each reagent portion Ca included in the captured image and makes a judgment regarding each inspection item. The determination unit 93 may store threshold values ​​and calculation formulas corresponding to the test items. Teacher data may be used for the determination by the determination unit 93.

[0043] Next, we will return to the description of the illumination unit 33. As shown in Figs. 4, 6, and 7(a), in this embodiment, a circular hole 33f is formed around the optical axis L32 of the lens unit 32a. More specifically, the hole 33f is an inner area partitioned by the circular partition wall 31f. Since the lens unit 32a is inserted into the insertion hole 31aa as described above, strictly speaking, the hole 33f forms a doughnut-shaped area. The light-emitting unit 33a is provided only outside the hole 33f (i.e., the partition wall 31f). The plate-shaped light-emitting unit 33a is fitted outside the partition wall 31f. The area including the thickness of the hole 33f and the partition wall 31f does not contribute to light emission. That is, a non-light-emitting unit 34 is formed around the optical axis L32 of the camera 32. In this embodiment, the non-light-emitting unit 34 forms a circle centered on the optical axis L32.

[0044] With the above configuration, the light-emitting portion 33a of the illumination portion 33 is provided in an area spaced apart from the optical axis L32. More specifically, the light-emitting portion 33a of the illumination portion 33 is provided in an area spaced apart from the optical axis L32 by a distance greater than the radius of the lens portion 32a. The distance based on the optical axis L32 is constant in, for example, the Y direction, the X direction, and any other horizontal direction. In this way, in the imaging device 30, a non-light-emitting portion 34 that does not contribute to illumination is formed in the central area of ​​the upper wall portion 31a.

[0045] The imaging device 30 of this embodiment has a feature of the inner wall surface A (a reflective surface made of a white material, also referred to as a first feature) and a feature of the light emitting portion 33a (a distance from the optical axis L32, also referred to as a second feature), thereby realizing unique illumination of the imaging surface 31da. The distribution of the amount of light reaching the imaging surface 31da will be described in detail with reference to Figures 7(a), 7(b), 8(a) and 8(b).

[0046] FIG. 7(b) is a view showing the imaging chamber from below. FIG. 7(b) also shows the test paper C placed on the imaging surface 31da. As shown in FIG. 7(b), the ratio of the area where the light emitting unit 33a is provided to the total area of ​​the area (area defined between the inner surfaces of the pair of step surface parts 31g) facing the inside of the imaging chamber 31 in the upper wall part 31a is, for example, 53% or less. This ratio is a value that can change depending on the imaging range and the type of the camera 32. The ratio of the area where the light emitting unit 33a is provided can also be called the "effective illumination area" excluding the lens part 32a and the non-light emitting part 34 of the camera 32. The end of the test paper C protrudes outside the pair of step surface parts 31g (surfaces where the pair of light source parts 33b are attached) when viewed from the bottom. The above ratio may be 60% or less.

[0047] FIG. 8(b) is a diagram showing the light quantity distribution (simulation result) of the illumination light based on the imaging device 30. The horizontal axis in FIG. 8(b) indicates the position (unit: millimeters: mm) in the front-rear direction (Y direction), and the vertical axis indicates the illuminance (unit: lux: lx). The origin (zero position) on the horizontal axis in FIG. 8(b) corresponds to the position of the optical axis L32 in FIG. 8(a). In addition, both ends (positions of 60 mm and -60 mm) on the horizontal axis in FIG. 8(b) correspond to the positions of the inner surface of the first side wall portion 31b in FIG. 8(a). For the light quantity distribution shown in FIG. 8(b), the "light quantity" is calculated as an integral value. As shown in FIG. 8(a) and FIG. 8(b), of the light amount (total light amount) of the illumination light illuminating the imaging surface 31da, the light amount of the indirect illumination light reflected from the light emitting unit 33a by the inner wall surface A and irradiated onto the imaging surface 31da is greater than the light amount of the direct illumination light directly irradiated onto the imaging surface 31da from the light emitting unit 33a. More specifically, of the light amount of the illumination light illuminating the imaging surface 31da, the light amount of the indirect illumination light is preferably 60% or more. Of the light amount of the illumination light illuminating the imaging surface 31da, the light amount of the indirect illumination light is more preferably 70% or more. Of the light amount of the illumination light illuminating the imaging surface 31da, the light amount of the indirect illumination light is preferably 85% or less. The sum of the light amounts of the indirect illumination light and the direct illumination light corresponds to the total light amount of the illumination light for the imaging surface 31da.

[0048] Those skilled in the art can calculate the (amount or ratio of) the indirect illumination light and direct illumination light described above using an appropriate method. For example, if the inner wall surface A is assumed to be black, the reflectance will be zero. The irradiation conditions in the illumination unit 33 are set constant, and the amount of illumination light when the reflectance is zero corresponds to the amount of direct illumination light. Next, the amount of indirect illumination light is calculated by subtracting the amount of direct illumination light from the total amount of illumination light when the inner wall surface A is a reflective surface made of a white material.

[0049] 8(b), the total illumination light (shown by a solid line) exhibits a light amount distribution in which the light amount decreases slightly as it approaches the center position (the position of zero on the horizontal axis) corresponding to the position of the optical axis L32. In other words, the light amount distribution of the illumination light exhibits a concave shape with a slightly depressed (depressed) center. From another perspective, the total illumination light exhibits a light amount distribution in which the light amount increases slightly as it moves away from the center position (the position of zero on the horizontal axis) corresponding to the position of the optical axis L32.

[0050] The indirect illumination light also has a concave shape, but the curvature of the concave (the degree of light reduction at the center position) is larger than that of the total illumination light. On the other hand, the direct illumination light has a light amount distribution in which the light amount increases slightly as it approaches the center position (the position of zero on the horizontal axis) corresponding to the position of the optical axis L32. In other words, the light amount distribution in the direct illumination light has a convex shape with the center slightly bulging (increasing). At any position on the imaging surface 31da, the illuminance of the indirect illumination light is higher than that of the direct illumination light. In both the total illumination light and the indirect illumination light, a reduction in illuminance is observed near both ends (near 60 mm and -60 mm). The area where the illuminance is reduced is an area outside the edge of the test paper C, so it does not affect the imaging of the test paper C. In other words, in both the total illumination light and the indirect illumination light, the concave area is formed to include the entire test paper C.

[0051] An imaging device 30X according to a reference embodiment will be described with reference to Fig. 9(a) and Fig. 9(b). Comparative Example 1 shown in Fig. 9(b) is an illumination light when the light emitting unit 33X is provided up to the vicinity of the lens unit 32a (the distance is approximately equal to the radius of the lens unit 32a) and the inner wall surface A is set to black. Comparative Example 2 is an illumination light when the light emitting unit 33X is spaced from the optical axis L32 as in the above embodiment and the inner wall surface A is set to black. The illumination light shown in Fig. 9(b) shows a light amount distribution in which the light amount decreases as it moves away from the center position (the position of zero on the horizontal axis) corresponding to the position of the optical axis L32, that is, as it approaches the end. This is a state in which peripheral shading occurs, and is not desirable.

[0052] As shown in FIG. 8(a) and FIG. 8(b), according to the imaging device 30 of this embodiment, a non-light emitting portion 34 is formed around the optical axis L32 of the camera 32 in the upper wall portion 31a. The planar light emitting portion 33a is provided in an area spaced apart from the optical axis L32 of the camera 32. In addition to this configuration, the inner wall surface A of the first side wall portion 31b and the second side wall portion 31c is a reflective surface made of a white material. In the imaging device 30, in addition to these configurations, the amount of indirect illumination light is greater than the amount of direct illumination light. Due to the greater amount of indirect illumination light, the effect of vignetting at the end of the imaging surface 31da that is relatively close to the inner wall surface A is reduced. According to the imaging device 30, the luminance in the captured image is made uniform, so that complicated correction in the image processing by the image processing unit 92 is not required. Furthermore, since light reflection by a reflective surface (inner wall surface A) made of a white material is utilized, the outer shape of light-emitting portion 33a is equal to or smaller than imaging surface 31da, and there is no need to enlarge light-emitting portion 33a.

[0053] Of the illumination light illuminating the imaging surface 31da, the amount of indirect illumination light is 60% or more. This increases the amount of illumination light (indirect illumination light) passing through the inner wall surface A, making it possible to more effectively reduce the effect of peripheral light falloff.

[0054] The ratio of the area where the light-emitting unit 33a is provided to the total area of ​​the upper wall portion 31a facing the inside of the imaging room 31 is 53% or less. This optimizes the area of ​​the light-emitting unit 33a in the area away from the optical axis L32 of the camera 32, and makes it possible to more effectively reduce the effect of peripheral darkening.

[0055] Although the embodiment of the present disclosure has been described above, the present invention is not limited to the above embodiment. For example, the light source unit 33b and the light emitting unit 33a are not limited to being provided separately, and the planar light emitting unit may be configured with a light source such as an LED or a fluorescent lamp. In this case, a plurality of LEDs or a plurality of fluorescent lamps may be arranged in a planar manner (in the X direction and the Y direction).

[0056] The configuration of the imaging chamber 31 is not limited to the above. The imaging chamber 31 is not limited to having a pair of first side walls 31b and a pair of second side walls 31c as the peripheral wall, and the peripheral wall may be a polygonal tube having five or more sides, or may be a cylindrical shape. In the above embodiment, the upper wall 31a and the bottom wall 31d face each other in the vertical direction. However, the facing wall and the imaging surface may face each other in a direction other than the vertical direction. In that case, the test paper C placed on the imaging surface may be held on the imaging surface by an appropriate means, as necessary.

[0057] The shape of the non-light emitting portion 34 is not limited to a circle. The non-light emitting portion is not limited to being formed in only one place, and a plurality of non-light emitting portions may be formed on the upper wall portion 31a (opposing wall portion). [Explanation of symbols]

[0058] DESCRIPTION OF THE SYMBOLS 1...urinalysis apparatus, 2...apparatus main body, 3...mounting table, 9...spotting device, 10...first transport mechanism, 20...second transport mechanism, 30...imaging device (test paper imaging device), 31...imaging chamber, 31a...upper wall portion (opposing wall portion), 31b...first side wall portion (circumferential wall portion), 31c...second side wall portion (circumferential wall portion), 31d...bottom wall portion, 31da...imaging surface, 32...camera, 32a...lens portion, 32b...imaging portion, 33...illumination portion, 33a...light emitting portion, 33b...light source portion, 40...supply mechanism, 60...disposal box, 100...spitts, C...test paper, Ca...reagent portion, L32...optical axis, Pa...spotting position, Pb...imaging position, R...rack.

Claims

1. A test strip imaging device for imaging an elongated test strip placed on an imaging surface, comprising: an imaging chamber including the imaging surface, an opposing wall portion opposing the imaging surface, and a peripheral wall portion extending in a direction intersecting the imaging surface and the opposing wall portion and surrounding the imaging surface; A camera installed in a central portion of the opposing wall portion; an illumination unit that is installed on the opposing wall and that irradiates illumination light from a planar light-emitting unit toward the imaging surface and an inner wall surface of the peripheral wall, the light-emitting portion of the illumination unit is provided in a region spaced from an optical axis of the camera by forming a non-light-emitting portion around the optical axis of the camera, The inner wall surface of the peripheral wall portion is a reflective surface made of a white material, a light amount of indirect illumination light reflected from the light-emitting unit on the inner wall surface and irradiated onto the imaging surface is greater than a light amount of direct illumination light directly irradiated onto the imaging surface from the light-emitting unit.

2. 2. The test strip imaging device according to claim 1, wherein the proportion of the indirect illumination light in the amount of illumination light illuminating the imaging surface is 60% or more.

3. 3. The test strip imaging device according to claim 1, wherein a ratio of an area where the light emitting portion is provided to a total area of ​​the opposing wall portion facing the inside of the imaging chamber is 53% or less.

Images