JP4854230B2 - Light irradiation device and light transmission element - Google Patents

Description

  The present invention measures the form of small bodies that flow in a medium, such as plankton drifting in water, droplets falling in the air, and mist-like substances, and the volume and moving speed are calculated from the results. The present invention relates to a small body measuring device and the like.

  Conventionally, in this kind of small body measuring apparatus, as shown in Non-Patent Document 1, a very thin distribution space (flow passage) is provided, and a small body passing through the space is imaged by a camera, and the image is displayed. Processing is performed to determine the form such as the contour of each body.

  The reason why the distribution space with such a small thickness is provided is to focus the camera. If the distribution space is thick like a cylinder, of the small bodies passing through the distribution space, This is because only the image at the focal position can be imaged, and an out-of-focus small body image may interfere.

  However, with such a configuration, the shape of the distribution space cannot be freely set, and the small body is difficult to guide to the distribution space, so the degree of freedom of measurement is limited.

Also, if you use a camera with a telecentric optical system, you can theoretically prevent out-of-focus, but the actual telecentric optical system has an unmistakable focus, and no matter how you configure it, it completely prevents out-of-focus. The reality is that it is difficult to realize. Furthermore, the telecentric optical system has a complicated configuration and is expensive, and also has a problem that an image tends to be dark and SN is deteriorated.
Handbook Image Processing Engineering-Advanced Edition (Kyoritsu Shuppan) 1999

  Accordingly, the present invention provides a small body measuring apparatus that can be configured at a low cost with a very simple structure, and that does not cause out-of-focus and has almost no restrictions on the shape of the flow path through which the small body passes, and an optical device used therefor. This is the main desired task.

  That is, the small body measuring apparatus according to the present invention measures the form of one or a plurality of small bodies flowing in a medium, and includes a light source and parallel light that travels light emitted from the light source in a predetermined optical axis direction. A collimating lens, a condensing lens disposed at a certain distance from the collimating lens in the optical axis direction, a flow path provided between the lenses and passing through the small body in a direction across the light, and And an optical sensor that receives light from the condenser lens and outputs image data including outline information of the body.

  If this is the case, since the light is parallel in the flow path, no matter where the small body is located in the flow path, particularly in the optical axis direction, the outline of each small body is not out of focus, It can be reliably detected by an optical sensor. In addition, since the distance between each lens can be set arbitrarily, the shape of the flow path can be set freely, such as with a thick and thick cross section, and various body sizes can be measured in response to various situations. can do. Furthermore, since the necessary basic components are only the light source, the pair of lenses, the optical sensor, and the member for forming the flow path, the configuration is very simple and the cost can be reduced.

  The effect of the present invention is particularly remarkable in comparison with the prior art when the width of the flow path in the optical axis direction is large enough to allow a plurality of the small bodies to pass through.

  In order to deal with various applications, based on the image data, a volume calculation unit that calculates an amount related to the volume of the small body in the flow passage, and a plurality of the image data are obtained at regular time intervals, and these images are acquired. It is preferable to further include a speed calculation unit that calculates an amount related to the moving speed of the small body from the data.

  In order to reduce the size in the optical axis direction, a Fresnel lens may be used for each of the lenses. In addition, since there is a flow passage through which the small body passes between the lenses, depending on the configuration, this lens itself may be a wall that forms the flow passage. In order to facilitate the removal of dirt, it is desirable to arrange the lenses so that the surfaces facing each other are flat and the surfaces facing each other are lens surfaces.

  As the light source, a light source provided with an LED is suitable in consideration of life, speed response, and efficiency.

  According to the present invention configured as described above, since the light is parallel in the flow path, the contour of each small body is in focus regardless of the position of the small body in the flow path, particularly in the optical axis direction. It can be reliably detected by the optical sensor without blurring.

  In addition, since the distance between each lens can be set arbitrarily, the shape of the flow path can be set freely, such as with a thick and thick cross-section, and various bodies can be measured in various situations. can do.

  Furthermore, since the necessary basic components are only the light source, the pair of lenses, the optical sensor, and the member for forming the flow path, the configuration is very simple and the cost can be reduced.

  An embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIGS. 1 and 2, the small body measuring apparatus 1 according to the present embodiment measures the form (particularly the contour) of a large number of small bodies 2 that flow in a medium. Here, for example, the case where the medium is water and the small body 2 is plankton or dust floating in the water will be described as an example. In addition, the small body 2 means the thing of the magnitude | size which can enter at least several (5-9 or more) at the same time in the flow path mentioned later.

  The small body measuring apparatus 1 includes an optical device 3 for condensing the small body 2 by irradiating it with parallel light L2, and an area serving as an optical sensor for receiving the light L3 condensed to a predetermined radius by the optical device 3. An image sensor 4 and an information processing device 5 that calculates various information from image data output from the area image sensor 4 are provided.

  Each part will be described.

  The optical device 3 includes a light source 6, a parallelizing lens 7 that converts the light L 1 emitted from the light source 6 into parallel light L 2 that travels in a predetermined optical axis direction C, and a constant distance from the paralleling lens 7 in the optical axis direction C. A condensing lens 8 disposed at a distance from each other and a flow passage 9 provided between the lenses 7 and 8 and passing through the small body 2 in a direction crossing the light L2 are provided.

  Here, the light source 6 can be regarded as a substantially point light source configured using, for example, LEDs, and has a certain degree of directivity.

  For example, a Fresnel lens is used as the collimating lens 7 and the condenser lens 8. The surfaces 7a and 8a facing each other are arranged as lens surfaces, and the surfaces 7b and 8b facing each other are arranged as planes.

  The flow passage 9 introduces the small body 2 from the introduction port 91 and leads out the small body 2 from the lead-out port 92, and is formed of a transparent member (not shown) that transmits the light L2. Further, the size of the flow passage 9 is set such that the plurality of the small bodies 2 can pass through both the width in the optical axis direction and the width in the direction perpendicular to the optical axis direction in the cross section.

  The area image sensor 4 is, for example, a plurality of CCDs arranged side by side in a plane, and an imaging optical mechanism (not shown) is provided in the preceding stage. Then, the cross section of the light L3 that has passed through the condenser lens 8 is formed on the light receiving surface of the sensor 4 so as to form an image in a state where it substantially coincides with or slightly smaller than the size thereof. The image data including the contour information is output.

  As shown in FIG. 3, the information processing apparatus 5 is, for example, a general-purpose computer including a CPU 101, a memory 102, an I / O channel 103, and the like, and is connected to a display 104, an input unit 105 such as a mouse and a keyboard, and the like. .

  Then, by installing a predetermined program in the information processing apparatus 5 and cooperating the CPU 101 and peripheral devices based on the program, the information processing apparatus 5 receives the image data from the area image sensor 4, An image processing unit 51 that performs contrast processing on the image data and outputs the image data to the display, or an amount related to the volume of the small body 2 in the flow passage 9 is calculated based on the image data processed by the image processing unit 51. It functions so as to function as the volume calculation unit 52 or the like (shown in FIG. 1).

  More specifically, in the image data initially transmitted from the area image sensor 4, the portion where the small body 2 is present and the light is blocked is dark and the other portions are bright. Then, in order to make this more obvious, for example, a black and white binarization process is performed so that the part where the small body 2 exists is black and the other part is white. An example in which this image data is represented on a display is schematically shown in FIG.

  The volume calculation unit 52 calculates the total volume of the small body 2 in the flow passage 9 by calculating the area of the black region in the image data after image processing and multiplying it by a proportional constant. This is because the small body 2 is represented as a black area. Even if each small body 2 is far from or close to the area image sensor 4, the black area is shaded by the irradiation of the parallel light L2. For this reason, the area of the black region appears because it appears at the same magnification with respect to the cross section of each of the small bodies 2. For calculating the area of the black region, the number of small bodies 2 may be counted.

  Further, when the density of the small bodies 2 increases to some extent, the small bodies 2 overlap with each other when viewed from the optical axis direction C (the shadows overlap), and due to the influence, the area of the black region and the volume of the small body 2 are proportional to each other. The relationship breaks down. Therefore, in the volume calculation method of multiplying the proportionality constant described above, a measurement error occurs. To prevent this, the relationship between the area of the black region and the volume of the small body 2 is obtained in advance. It may be expressed by a calibration curve or the like, and the volume may be obtained from the area of the black region using the relationship.

  Therefore, according to the small body measuring apparatus 1 configured as described above, since the light is parallel in the flow path 9, no matter where the small body 2 is located in the flow path 9, particularly in the optical axis direction C. The contour shape of each small body 2 can be reliably detected by the area image sensor 4 without being out of focus.

  In addition, since the distance between the lenses can be set arbitrarily, the shape of the flow passage 9 can be freely set, for example, by making the flow passage 9 large in cross section, and various small bodies 2 corresponding to various situations. Can be measured.

  Furthermore, since the necessary basic components are only members for forming the light source 6, the pair of lenses 7, 8, the area image sensor 4 and the flow passage 9, the configuration is very simple and the cost can be reduced. .

  The present invention is not limited to the above embodiment.

  In terms of lenses, each lens itself may be part of the wall of the flow path. The lens is not limited to a Fresnel lens, and a normal convex lens may be used. The shape of the lens is not limited to a circle, and may be a square, a polygon, or the like due to the relationship with the casing. Furthermore, the surfaces of the lenses facing each other may be arranged to be a plane, and the surfaces facing each other to be a lens surface. In this way, since the flat surface is on the side of the flow passage that is easily contaminated, it is easy to wipe off dirt and the like.

  Further, an optical member such as a reflection mirror may be installed on the optical path from the light source to the area image sensor to bend the optical path.

  As far as the medium and the small body are concerned, the medium only needs to transmit light, and may of course be a gas such as air. Even if the small body blocks or transmits light, if it refracts and scatters light, that part can be detected darkly and can be measured. For example, a minute object such as a mist, a droplet, a glass ball, or the like is also a measurement target.

  With regard to the information processing apparatus, a plurality of image data may be acquired at regular time intervals, and a speed calculator that calculates an amount related to the moving speed of the small body from the image data may be further provided. This makes it possible to know the flow rate of the body per hour.

  The light source is not limited to one using an LED, and an LD or a light bulb may be used.

  In addition, the present invention is not limited to the illustrated examples and embodiments, and various modifications can be made without departing from the gist thereof.

1 is a schematic schematic overall view showing a light irradiation apparatus according to an embodiment of the present invention. The typical perspective view which shows the light irradiation apparatus in the embodiment. The typical schematic whole figure which shows the light irradiation apparatus in the embodiment. The image illustration figure in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Small body measuring apparatus 2 ... Small body 3 ... Optical apparatus 4 ... Optical sensor (area image sensor)
52 ... Volume calculation unit 6 ... Light source 7 ... Parallelizing lenses 7a, 8a ... Opposite surfaces 7b, 8b ... Opposite surfaces 8 ... Condensing lens 9 ...・ Flow path C: Optical axis

Claims (5)

Measuring a form of one or a plurality of droplets falling in the air, a light source, a collimating lens for converting light emitted from the light source into parallel light traveling in a predetermined optical axis direction, and the collimating lens And a condensing lens disposed at a certain distance from the lens in the optical axis direction, and is provided between the lenses, and extends vertically so that droplets are introduced from the introduction port at the upper end and are ejected from the exit port at the lower end. A flow path, and a light sensor that receives light from the condensing lens and outputs image data including outline information of a droplet, the lower part of the wall around the introduction port, and The lens is arranged at a predetermined distance outside the edge of the introduction port as seen from the center line of the flow path, and the volume calculation for calculating the total volume of droplets in the flow path based on the image data The volume calculation unit Using a calibration curve representing the relationship between the total volume of the total area and a droplet of a region where the liquid droplets are present, the total area of the region where the droplets are present, by determining the total volume of the droplet An apparatus for measuring dropped liquid droplets, which corrects errors caused by overlapping of liquid droplets when viewed from the optical axis direction .   2. The falling droplet measuring apparatus according to claim 1, wherein a width of the flow path in the optical axis direction is large enough to allow a plurality of the droplets to pass therethrough.   The falling droplet measuring apparatus according to claim 1, further comprising a speed calculating unit that acquires a plurality of the image data at regular time intervals and calculates an amount related to a moving speed of the droplet from the image data.   4. The falling droplet measuring device according to claim 1, wherein each of the lenses is a Fresnel lens, and the surfaces facing each other are flat and the surfaces facing each other are lens surfaces. The falling droplet measuring apparatus according to claim 1, wherein the light source includes an LED.