WO2016117460A1 - Water quality inspection system - Google Patents

Abstract

[Problem] To provide a practical water quality inspection system that makes it possible to rapidly measure the quantity of microorganisms included in a large volume of target water while the water is flowing through piping. [Solution] The interior of transparent piping 1 through which target water W is made to flow is irradiated with coherent light and an interference fringe of object light from within the piping 1 and reference light is captured by an imaging element 32. A data processing unit 36 reproduces an image for hologram data acquired for each of imaging cycles set in accordance with the flow rate and the width of an imaging area and performs identification and quantitative measurement of an image of microorganisms M by comparing with sample data at the time of image reproduction.

Description

Water quality inspection system

The invention of this application relates to a water quality inspection system, and more particularly to a system used in a water quality inspection that requires the measurement of the number of biological fines such as aquatic microorganisms. It is related with the system used suitably when it is going to test | inspect water of this for a short time.

Due to the growing environmental awareness, attention is being focused on various water-related technologies. Water-related technologies include technologies for producing clean water, such as water purification systems, as well as technologies for checking water quality, that is, water quality inspection technologies. This field is also actively researched and developed. Yes.
Of these, certain types of water quality testing may require testing of biological microscopic materials such as underwater microorganisms, and it is necessary to know what types of biological microscopic materials are present and how many. There may be. This point will be described by taking an example of inspection of ballast water of a ship.

Ballast water is water used as a ballast for ships. When leaving a port without loading, the seawater of the port is loaded into the ballast tank at the port of departure. And it is discharged when loading luggage at the port of call. In doing so, it has been pointed out that the aquatic organisms contained therein have an impact on the ecosystem as alien species. For this reason, the Ballast Water Management Convention (official name: regulation of ballast water and sediment on ships) And an international treaty for management) has been concluded, and Japan ratified it in 2014. The official entry into force of the treaty imposes a requirement that in more than 30 ratifying countries, the volume of merchant vessels in the ratifying countries will be 35% or more of the total volume of merchant vessels in the world in the next year (2015). These requirements are expected to be met and the move towards the entry into force of the Convention is accelerating.

On the other hand, there are many technical challenges to fulfill the treaty obligations, many of which remain unresolved. One such unresolved issue is ballast water testing technology. Section D of the Convention includes standards for ballast water that may be discharged:
1. Living organisms with a minimum diameter of 50 μm or more (mainly zooplankton): the number of surviving individuals in a cubic meter is less than 10,
2. Organisms with a minimum diameter of 10 μm or more and less than 50 μm (mainly phytoplankton): the number of surviving individuals in 1 ml is less than 10,
Standards such as are established. Therefore, a treatment technique for treating the ballast water so as to satisfy the standard is necessary, and a technique for inspecting whether the treated water satisfies such a standard is necessary.

However, a practical technique capable of measuring the number of living microorganisms in a large amount of water such as ballast water has not been developed so far. As such an inspection technique for underwater microorganisms, a culture method, a staining method, and the like are known. In the culture method, water to be examined (hereinafter referred to as “target water”) is smeared on an agar medium formed on a petri dish and allowed to stand on the agar medium for about one day under a constant temperature condition. The microorganism colonies formed are discriminated, and the number of colonies is counted to indirectly determine the number of living microorganisms in the target water.
In the staining method, a reagent that reacts with the respiratory activity of microorganisms is included in the target water. The microorganisms that have taken in this reagent are stained by respiration, and the number of microorganisms in the target water is measured by counting the stained microorganisms with a microscope or the like.

These methods are methods in which the target water is collected as a sample and brought into a laboratory or the like for inspection. Considering the field of ballast water treatment and management, such a method is not practical and seems to be almost impossible to adopt. That is, although some ballast water treatment apparatuses have already received approval, it is assumed that these treatment apparatuses are mounted on ships and discharged after treating ballast water. Assuming such a ballast water management site, it is desirable that the number of remaining microorganisms can be measured on the discharge path (pipe) of the ballast water treated by the ballast water treatment device in the ship. In other words, when loading ballast water into a ship or discharging ballast water, a system that can inspect ballast water flowing in or out on the spot and measure the number of living microorganisms is expected as a useful system that can withstand practical use. The

The above is a problem in the field of ship ballast water management. In addition to this, for example, even in water quality inspections at pools, beaches, hot spring facilities, etc., a system that can be inspected on the spot without special sampling is provided. If so, its usefulness seems to be extremely high. If inspection can be performed on the spot where the target water is flowing, a large amount of target water can be inspected in a short time, and a total amount inspection (for example, a total amount inspection of water to be put in a pool) can be performed.

The invention of this application has been made in consideration of the above points, and can be used to measure the number of biosubstances contained in a short period of time for a large amount of target water while the water is flowing in the pipe. It is a problem to provide a practical system.
In the invention of this application, the object to be counted is a living body, but is not necessarily limited to a living organism (microorganism), and may be bacteria or a certain kind of cell. Accordingly, these are collectively referred to as “biological fine objects” and a system for measuring the number is provided.

In order to solve the above-mentioned problem, the invention according to claim 1 of this application is a water quality inspection system for measuring the number of biological fines in target water,
A water supply system that sends the target water through a pipe;
And a detection system that detects the number of biological fines in the target water sent through the piping by the water supply system,
The pipe has a transparent part,
The detection system detects the number of living body fine objects by taking an image of the target water flowing in the pipe through the transparent part,
The detection system is
A light source that emits coherent light;
An image sensor;
The coherent light is irradiated into the pipe through the transparent part, the object light that is light from the target water in the pipe is guided to the image sensor through the transparent part, and the coherent light not including object information is used as the reference light. An optical system that causes the imaging device to image interference fringes by causing interference on the imaging surface of the imaging device, and
A data processing unit that processes hologram data that is data of interference fringes imaged by the image sensor;
The data processing unit acquires hologram data with a period according to the water supply speed in the pipe by the water supply system and the length in the water supply direction in the imaging region by the image sensor,
The data processing unit counts the number of living body fine objects by playing back each acquired hologram data, and the number of objects determined to be images of living body fine objects at the time of image reproduction for each hologram data It is configured to perform data processing for counting.
In order to solve the above problem, the invention according to claim 2 is the configuration according to claim 1, wherein the data processing unit identifies what kind of biological microscopic object is the image and determines the number. It has a configuration that performs data processing for counting.
In order to solve the above problem, the invention according to claim 3 is the configuration according to claim 1 or 2, wherein the data processing unit reproduces each hologram data for each set reproduction distance pitch. For each reproduction plane having a different reproduction distance, it is determined whether or not an image of a biological fine object can be included according to the luminance value of the reproduction plane, the reproduction plane determined to include is extracted, and the biological image is reproduced on the reproduction plane It has a configuration in which data processing is performed to count the number of objects determined to be fine objects.
In order to solve the above-mentioned problem, the invention according to claim 4 has a configuration in which, in the configuration of claim 3, the luminance value is a phase value of a result of reproduction calculation of each hologram data. .
In order to solve the above-mentioned problem, the invention according to claim 5 is the structure according to any one of claims 1 to 4, wherein the data processing unit uses a living body for an image obtained when the hologram data is reproduced. By comparing with specimen data of fine objects, it is determined whether or not the image is a fine biological object, and the number is counted according to the result.
In order to solve the above-mentioned problem, according to a sixth aspect of the present invention, in the configuration according to any one of the first to fifth aspects, the data processing unit is alive after performing life / death discrimination on the image of the biological fine object. It is possible to count the number of items that are present.
In order to solve the above problem, the invention according to claim 7 is the configuration according to any one of claims 1 to 6, wherein the optical system includes an irradiation optical system for irradiating coherent light in the pipe, and a pipe. An imaging optical system that captures object light from the target water inside the imaging optical system, and the imaging optical system captures transmitted light from the inside of the pipe irradiated with coherent light by the irradiation optical system. It has the structure that it is made to inject into.
In order to solve the above-mentioned problem, the invention according to claim 8 is the structure according to any one of claims 1 to 7, wherein the target water is a ballast water of a ship and is a ballast water inspection system. Have.

As described below, according to the invention described in claim 1 of this application, the inside of the pipe through which the target water flows is photographed, and measurement is performed on the spot based on the photographed data. It is suitable for testing a large amount of water in a short time. Further, since the photographing is hologram photographing and the number of living body fine objects in the target water is measured using digital reproduction (digital holography) of the hologram, it is further preferable from the viewpoint of inspecting a large amount of water in a short time. It will be something.
In addition, according to the invention described in claim 2, since what number of living body fine objects are present is detected together with the number, more specific inspection such as whether or not there are living body minute objects in question. The result can be obtained.
According to the invention described in claim 3, in addition to the above effect, the hologram data obtained by one imaging is not analyzed on all reproduction surfaces for each reproduction distance pitch, but an image of a biological fine object. Since the reproduction surface determined to be present is extracted and analyzed, the time required for the inspection can be further shortened.
Further, according to the invention described in claim 4, in addition to the above effect, the phase value is used as the luminance value at the time of extraction of the reproduction surface, so that it is more suitable for the purpose of detecting biological fines in water. Become.
Further, according to the invention described in claim 5, in addition to the above-described effect, the sample data is used for the detection of the fine biological matter, so that the effect of shortening the time required for the measurement and preventing the erroneous detection can be obtained. .
Further, according to the invention described in claim 6, in addition to the above-described effect, it is possible to add life / death discrimination of living body fine objects as an inspection item, so that it is suitably used in applications where it is necessary to know the number of living things. can do.
Moreover, according to invention of Claim 7, said each effect can be show | played in the ballast water test | inspection of a ship. This makes it extremely useful in using treaty obligations for ballast water management.

It is a schematic diagram of a water quality inspection system of an embodiment. It is the schematic which showed the structure of the detection system in the water quality inspection system shown in FIG. It is the isometric view schematic which showed the relationship between the imaging surface in an image sensor, and a transparent tube. It is the schematic perspective view shown about the area | region (photographing area | region) of the target water image | photographed by one imaging | photography. It is the flowchart which showed the outline of the measurement program. It is the isometric view schematic shown about the reproduction | regeneration calculation module. It is the perspective view which showed typically about the reproduction | regeneration surface extraction module. It is the perspective view which showed typically about the identification counting module. It is the flowchart which showed the outline of the identification counting module. It is a figure which shows roughly an example of the execution result of the measurement program by an output module.

Next, modes for carrying out the invention of the present application (hereinafter referred to as embodiments) will be described.
FIG. 1 is a schematic diagram of a water quality inspection system according to an embodiment. The water quality inspection system shown in FIG. 1 is a system configured assuming ballast water inspection. A major characteristic point of this system is that it is a system that measures the number of contained biological fine substances M on the spot on the pipe 1 for sending the target water (ballast water) W. That is, this system includes a water supply system 2 that sends the target water W through the pipe 1 and a detection system 3 that detects the number of the biological fines M in the target water W when being sent through the pipe 1 by the water supply system 2. Configured.

Specifically, as shown in FIG. 1, the water supply system 2 includes a water supply side tank 21 that temporarily stores the target water W for inspection, and a water receiving side that temporarily stores the target water W that has been inspected. A tank 22, pipes 1, 101, 102 provided to connect the water supply side tank 21 and the water reception side tank 22; a pump 23 that sends the target water W from the water supply side tank 21 through the pipes 1, 101, 102; An anemometer 24 for detecting the flow velocity of the target water W is provided.

The pipe is transparent in the portion 1 that passes through the place where the detection system 3 is disposed (hereinafter referred to as a transparent pipe). Normal pipes 101 and 102 are connected before and after the transparent pipe 1, and target water is sent from the water supply side tank 21 to the transparent pipe 1 by the pipe (hereinafter referred to as an inflow pipe) 101, and passes through the transparent pipe 1. Further, it is discharged through another pipe (hereinafter referred to as an outflow pipe) 102. The transparent tube 1 is a cylindrical member formed of a transparent material such as glass or acrylic resin. In this embodiment, the cross section has a rectangular shape (that is, a rectangular tube shape).

Another major feature of the system of this embodiment is that the detection system 3 images the target water W flowing in the transparent tube 1 in order to enable in-situ measurement. The number of the biological fine objects M is detected by analyzing the obtained data (imaging data). A further significant feature of the system of the embodiment is that the detection system 3 captures an image of the flowing target water W as a hologram instead of a normal two-dimensional image.

The detection system 3 will be described more specifically with reference to FIG. FIG. 2 is a schematic diagram showing the configuration of the detection system 3 in the water quality inspection system shown in FIG. As shown in FIG. 2, the detection system 3 includes a light source 31 that emits coherent light, an image sensor 32, optical systems 33 to 35, and a data process 36 that processes image data captured by the image sensor 32. I have.
As the coherent light source 31, a laser oscillator is used. For example, a HeNe laser oscillator having a wavelength of 632.8 nm, a ruby laser oscillator having a wavelength of 694 nm, or the like is used.

A CCD or CMOS image sensor is used for the image sensor 32. Since the imaging element 32 is intended to measure the number of the biological fine objects M, a sufficiently fine pixel pitch is used. For example, in the case of a CCD, an image pickup surface having a size of about 5.6 × 5.6 mm and a number of pixels of about 1024 × 1024 (pixel pitch is about 5.5 μm) is used.

The optical system irradiates coherent light into the transparent tube 1, guides the object light, which is light from the irradiated target water (ballast water) W in the transparent tube 1, to the image sensor 32, and does not include object information. The coherent light is guided to the image sensor 32 as reference light and caused to interfere with the imaging surface of the image sensor 32 to cause the image sensor 32 to image the interference fringes.
As an optical system, an optical system 33 for irradiating light from the coherent light source 31 into the transparent tube 1 and irradiating the target water W, and light (object light) from the irradiated target water W to the image sensor 32. An imaging optical system 34 for guiding and a reference light optical system 35 for guiding coherent light not including object information to the imaging element 32 as reference light are provided.

“Object information” is a term that assumes that the wavefront of coherent light changes according to the properties (shape, refractive index, etc.) of the object when the object is irradiated with coherent light. It is a term meaning object information that can be expressed by. For example, when an image of an object is reproduced by a wavefront, the shape of the object is “object information”. When the transmittance distribution in the object is obtained from the wavefront, the transmittance distribution is “object information”. Coherent light that does not include such object information (in this embodiment, coherent light that has not passed through an object) is used as reference light.

In principle, it is possible to use separate light sources for object light and reference light, but using separate light sources makes it possible to sufficiently align the wavelength and phase (make it coherent). difficult. For this reason, the light from one coherent light source 31 is divided and used. That is, as shown in FIG. 2, an extraction beam splitter 351 is provided on the optical path of the irradiation optical system 33, and a part of the light is extracted as reference light. Further, the reference light can be extracted from the object light. Specifically, there are two methods. First, as disclosed in FIG. 12 of Japanese Patent Application Laid-Open No. 2014-44095, after the light after object diffraction is separated into two by a beam splitter, a Fourier transform lens and a pinhole are combined on one side. In this method, the coherent light from which the object information is missing is extracted by passing through the spatial filter, and this is used as the reference light. The other is that, as disclosed in International Publication No. 2008/123408, a Fourier transform lens and a micro semi-transparent mirror are similarly arranged on the optical path of the light after object diffraction, and the zero-order light component of the object diffraction light Is used as a reference beam.

In this embodiment, light transmitted through the transparent tube 1 is incident on the image sensor 32. This light includes object light. The object light is diffracted light from the living body fine object M in the target water W irradiated with the coherent light, and the coherent light is scattered light by the living body fine object M (scattered light) and the living body. There are cases of light that is reflected by the minute object M (reflected light) and light that is transmitted through the minute object M (transmitted light). The object is to capture the light from the biological fine object M, image the interference fringes with the reference light, and measure the number of the biological fine object M. The object light may be any case. Scattered light, reflected light, and transmitted light may not be distinguished from each other, and even if they cannot be distinguished, there is no problem as long as the presence of the biological fine matter M can be determined. In this embodiment, the living body fine matter M is a microorganism or a bacterium in ballast water, and the living body fine matter M is often transparent. Therefore, the object light is mainly transmitted light.

As shown in FIG. 2, the imaging optical system 34 is provided between the transparent tube 1 and the imaging element 32. In the present embodiment, interference fringes obtained while enlarging and projecting inside the transparent tube 1 are recorded as hologram data. For this reason, the imaging optical system 34 includes an objective lens 341 and an imaging lens 342. As shown in FIG. 2, the imaging element 32 is arranged so that the imaging surface is perpendicular to the optical axis of the imaging optical system 34.
An integrating beam splitter 352 is provided on the optical path between the imaging lens 342 and the image sensor 32. The reference light optical system 35 is configured to guide the reference light extracted by the extraction beam splitter 351 to the integration beam splitter 352 by the mirror 353 and to enter the imaging element 32 together with the object light.

The reference light optical system 35 is configured to allow the reference light to be incident on the image sensor 32 in an off-axis manner. The off-axis means that the reference light is incident with an angle with respect to the object light instead of the same incident angle as the object light. Specifically, an off-axis driving mechanism 354 is attached to the mirror 353. The off-axis driving mechanism 354 is a mechanism that changes the mirror 353 from a 45 ° angle to a state inclined by a predetermined angle.

As shown in FIG. 2, the irradiation optical system 33 and the reference light optical system 35 are provided with beam expanders 331 and 355, and the coherent light is used after being expanded to a light beam of a necessary size. It is supposed to be. In each of the beam expanders 331 and 355, spatial filters 332 and 356 for noise removal are arranged as necessary.

The data processing unit 36 is specifically a computer, and includes a CPU as the arithmetic processing unit 361, a storage unit 362, a printer 363, a display 364, and the like as output units. The image sensor 32 is connected to the data processing unit 36 via an interface, and interference fringe data captured by the image sensor 32 is stored in the storage unit 362 of the data processing unit 36 as hologram data. ing. That is, the system of this embodiment inspects the target water W using digital holography, and recording of the hologram is performed by storing the captured interference fringe data as hologram data in the storage unit of the data processing unit 36. This is done by storing in 362. The storage unit 362 is a storage such as a memory or a hard disk.

The data processing unit 36 is installed with software for measuring the number of biological fine objects M in the target water W. The software includes various data used for the measurement program 366 for measuring the number of the biological fine objects M and the measurement program 366. These programs and data are stored in the storage unit 362. When the measurement program 366 is executed by the CPU 361, the number of fine biological objects in the target water W is measured, and this result is output. Hereinafter, an outline of the measurement program 366 will be described.

In the measurement program 366, the period for taking out the hologram data is determined by the relationship between the size of the imaging region by the image sensor 32 and the flow velocity in the transparent tube 1. Prior to detailed description of the program, this point will be described first.
3 is a schematic perspective view showing the relationship between the imaging surface of the imaging element 32 and the transparent tube 1, and FIG. 4 is a schematic perspective view showing an area (photographing area) of the target water W photographed by one photographing. It is.

In holography, an image of a space to be imaged is captured as interference fringes between object light and reference light, and the image is reproduced three-dimensionally based on the imaging result (hologram data). In the water quality inspection system of the embodiment, the object to be imaged is in the transparent tube 1. As shown in FIG. 3, the transparent tube 1 is formed of four transparent plate-like members, and among these, the plate-like member 11 on the image pickup device 32 side is called an observation plate. The imaging element 32 images the target water W in the transparent tube 1 through the observation plate 11.

As shown in FIG. 3, the optical axis 340 of the imaging optical system is perpendicular to the observation plate 11, and thus the imaging surface of the imaging element 32 is parallel to the observation plate 11. As shown in FIG. 3, the optical axis 340 of the imaging optical system 34 matches the direction of one side of the square (hereinafter referred to as the depth direction) in the cross-sectional shape of the transparent tube 1. This direction is the direction of the reproduction distance D in image reproduction described later.

When the imaging surface of the imaging device 32 is an xy plane, the xy direction coincides with the length direction of the transparent tube 1 (the direction of the flow of the target water W). The y direction coincides with the height direction of the transparent tube 1. The imaging region by the imaging device 32 is an internal space of the transparent tube 1 and therefore a rectangular parallelepiped box-shaped space region as indicated by R in FIG. Note that the length in the depth direction of the imaging region R is the length in the horizontal direction in the vertical cross section of the transparent tube 1. At the time of image reproduction, the image reproduction space is set so that the reproduction distance D is changed by this length.

The length of the imaging region R in the width direction (x direction) is determined according to the width of the imaging surface of the imaging element 32 and the magnification of the imaging optical system 34. This length determines the amount of the target water W to be photographed in one photographing, and is an important parameter. Hereinafter, this length is referred to as a photographing width, and is indicated by L in FIG. The photographing width L is, for example, about 0.05 to 100 mm.

The length h in the height direction (y direction) of the imaging region R is the height on the inner surface of the transparent tube 1 (hereinafter referred to as imaging height). A planar region having the photographing width L and the photographing height h is a region that the image sensor 32 expects in one photographing. Hereinafter, this planar area is referred to as one frame area. The imaging optical system 34 is designed to reliably anticipate one frame region according to the position and size of the imaging surface of the imaging device 32. The imaging optical system 34 is desirably a telecentric, particularly an object-side telecentric optical system, so that the lateral magnification does not change in the depth direction of the imaging region R.
In FIG. 3, the outline of the imaging region R in one imaging is indicated by a solid line. The target water W is successively sent to the transparent pipe 1 through the pipe 100 and flows. A region of the target water W to be photographed in the next photographing is indicated by a broken line in FIG.

Assuming that the flow velocity in the transparent tube 1 is V, the image pickup device 32 is configured to perform one shooting at a cycle of L / V. More precisely, the image pickup device 32 takes a picture with its own frame period, but for the actual calculation of the number of living body fine objects, the output of the image pickup element 32 is taken out with a cycle of L / V and taken out. The number of living body fine objects M is measured as the number confirmed by one shooting of output (hologram data). Hereinafter, this cycle is referred to as an imaging cycle.
In addition, when the living body fine substance M that can exist in the target water W is a microorganism and it is assumed that the living body M moves, the flow velocity V in the transparent tube 1 is sufficiently faster than the moving speed. The The flow velocity V is, for example, about 0.01 mm / s to 10,000 mm / s, and the imaging cycle is, for example, about 1 Hz to 1000 Hz.

The measurement program 366 measures the biological micro object M with respect to the hologram data output for each imaging cycle. Hereinafter, for convenience of explanation, hologram data output in one shooting is referred to as a data set. Each data set may be used by the measurement program 366 as it is output from the image sensor 32, or may be temporarily stored in the storage unit 362, and the measurement program 366 may be read from the storage unit 362 and used. When each data set is temporarily stored in the storage unit 362, it is stored so that the photographing order can be identified for each data set as in a database format.

The measurement program 366 will be described on the assumption of the above points. First, the entire measurement program 366 will be schematically described with reference to FIG. FIG. 5 is a flowchart showing an outline of the measurement program 366. As shown in FIG. 2, the measurement program 366 includes a reproduction calculation module, a reproduction surface extraction module, an identification counting module, an output module, and the like as subprograms.

The measurement program 366 finally confirms whether or not the biological fine object M exists in the entire imaging region R shown in FIG. 4 for one data set, and identifies and counts the presence of the biological fine object M in the hologram reproduction result. Based on. At this time, the measurement program 366 performs data processing since the reproduction distance D is not changed by a predetermined short distance (pitch) in the depth direction. Hereinafter, the pitch of the reproduction distance in the depth direction is referred to as a reproduction distance pitch. The reproduction distance pitch ΔD is determined according to the size of the biological fine matter M to be detected, but is generally about 0.1 μm to 10 mm.

First, the reproduction calculation module will be described. FIG. 6 is a schematic perspective view showing the reproduction calculation module. The reproduction calculation module is a module for calculating complex amplitude data of an image reproduction space (each reproduction plane) as an image reproduction preparation operation for one data set. Although this point is not significantly different from the reproduction of normal hologram data, the outline will be described with reference to FIG.
In holography, when an image is reproduced by numerical calculation, it is necessary to specify a hologram surface and a reproduction surface. The hologram surface is a surface on which the hologram exists, but here is the position of the imaging surface of the imaging device 32. Usually, in order to simplify the calculation, the reproduction surface is parallel to the hologram surface as shown in FIG.

The hologram data output from the image sensor 32 is a light intensity signal (light intensity distribution) in each pixel. Therefore, as shown in FIG. 6, the hologram data 321 can be defined as g (x, y). However, as described above, the hologram data 321 is interference fringes (partly enlarged in FIG. 6 and indicated by reference numeral 322) formed by the object light and the reference light, and the pattern of the interference fringes 322 is g ( x, y). As shown in FIG. 5, in order to simplify the calculation, the reproduction surface is an XY plane that shares the hologram surface and the Z axis. The distance D between the hologram surface and the reproduction surface is the reproduction distance described above and correlates with the distance in the depth direction described above in the imaging region R.

As an example, a case where reproduction is performed at a distance of Fresnel diffraction using Fourier transform will be described. Let r be the distance from one point on the hologram surface to one point on the playback surface. x and y are coordinates on the hologram surface, and X and Y are coordinates on the reproduction surface.
The complex amplitude distribution on the reproduction surface can be expressed as Equation 1 according to Kirchhoff's diffraction integral equation.

In Equation 1, λ is the wavelength of the reproduction light, and k is the wave number. If the Fresnel approximation shown in Formula 2 is applied and substituted into Formula 1, Formula 3 is obtained.

In Equation 3, if the integral is regarded as a Fourier transform and transformed, Equation 4 is obtained.

In Equation 4, the parentheses of F indicate Fourier transform. x and y are output values from each pixel on the imaging surface, and G (X, Y) is obtained by performing a discrete Fourier transform. As can be seen from Equation 4, the data G (X, Y) is a representation of the optical information of each point on the reproduction surface in the form of a complex number (complex amplitude data). Therefore, if the calculation in the middle is omitted, this data G (X, Y) is expressed by the following Equation 5.

Thus, the result of the reproduction calculation is complex amplitude data at each point on the reproduction surface, and the pitch depends on the pitch (pixel pitch) of the hologram data 321 as the original data. In digital holography, when an image is reproduced with amplitude information, | A | ² at each coordinate point is calculated from Equation 5 and output. When an image is reproduced with phase information, a deviation angle φ at each coordinate point is calculated and output. The output is an amplitude value distribution (amplitude value map) and a phase value distribution (phase value map) on the playback surface. When this is visualized by some method, an image of the target object is displayed in it. Will appear. In this embodiment, since the object to be imaged is water, an image thereof appears when the living body fine object M exists. These are performed by the identification counting module.

As shown in FIG. 5, the measurement program 366 first reads the first data set and stores it in a memory variable. “Reading a data set” means that when the output from the image sensor 32 is used as it is, the hologram data output at the timing immediately after the execution of the program is acquired from the image sensor 32 and used as a memory variable on the measurement program. Is to store. When each data set is stored in the storage unit 362, the first data set is read and stored in a memory variable.
As shown in FIG. 5, the measurement program executes the reproduction calculation module for the first data set, and stores the execution result in a memory variable. The execution result of the reproduction calculation module is a collection of complex amplitude data on each reproduction plane as described above.

Next, the measurement program executes a reproduction surface extraction module. As will be described later, the reproduction surface extraction module is a module that determines whether or not a reproduction image of the biological fine object M exists, and executes the identification counting module as a subprogram when it is determined that the reproduction image exists. The execution result of the identification counting module is the ID of the confirmed biological fine object M and the number thereof, and these are temporarily stored in the memory variable.
Then, the measurement program executes the reproduction surface extraction module in the same manner for the next reproduction surface, and executes the identification counting module for the reproduction surface where it is determined that the biological fine object M exists. The execution results of the identification counting module are summed up for each ID (in this embodiment, the ID of the sample data) that specifies what kind of biological fine object is the execution results up to that point.

When the reproduction surface extraction module and the identification counting module as its subprogram are executed for all reproduction surfaces, the processing for the data set is completed, and the measurement program reads the next data set. When the processing for all the extracted reproduction planes is completed, the processing for that data set is completed, and the counting program captures the next data set. Similarly, the reproduction calculation module, the reproduction surface extraction module, and the identification counting module in the case where it is determined that there is the biological fine object M are sequentially executed.
After performing such processing up to the last data set, the output module is executed. The execution of the output module ends the measurement program.

Next, the reproduction surface extraction module and the identification counting module will be described in more detail with reference to FIGS. FIG. 7 is a perspective view schematically showing the reproduction surface extraction module, FIG. 8 is a perspective view schematically showing the identification counting module, and FIG. 9 is a flowchart showing an outline of the identification counting module.
Extraction of the reproduction surface is not particularly essential, but is provided as a suitable configuration for inspecting a large amount of water in a short time. As described above, in the reproduction of the hologram, an image of each reproduction surface can be obtained by changing the reproduction distance. Therefore, a three-dimensional image of the entire photographing region R can be obtained by sequentially changing the reproduction distance with the reproduction distance pitch. The reproduction distance pitch is determined according to the size of the biological fine object M to be detected, the resolution of the imaging optical system 34, and the like. In FIG. 7, the image reproduction space is indicated as R ′. In the image reproduction space R ′, an image of the entire imaging region R is reproduced.

At this time, if all the reproduction surfaces (reproduction surfaces at each reproduction distance pitch) are analyzed to determine the presence / absence of an image of the biological fine object M, it takes a long time. It is determined in advance whether or not the reproduction surface needs to be analyzed, and only the reproduction surface P determined to be analyzed is extracted. This module is a reproduction surface extraction module.
There are several possible configurations of the reproduction surface extraction module. In this embodiment, the average luminance value of one entire reproduction surface is calculated and extracted depending on whether the difference with respect to the reference luminance value is more than the limit. It is to judge whether. The luminance value here means the brightness of the reproduced image on the screen, and is the above-described complex amplitude data (G (X, Y)).

In this embodiment, the target water W is assumed to have a constant concentration (light transmittance) as water, except that the biological fine matter M may be included. In addition, the intensity of coherent light at the time of holographic photography and the illumination conditions of the place where the apparatus is placed are always constant. Therefore, when the hologram is captured and reproduced, the luminance value of the water portion image is basically constant. When an image of the biological fine object M is taken and reproduced, the luminance value changes at that portion. Therefore, when a certain reproduction surface P includes the image of the biological fine object M, the average luminance value of the reproduction surface P changes compared to the case where the reproduction surface P does not include the image of the biological fine object M. In general, coherent light is scattered and absorbed by the biological fine object M. Therefore, the average luminance value of the reproduction surface P including the image of the biological fine object M is a reproduction in which no image of the biological fine object M exists. It is lower than the surface. Accordingly, whether or not the average luminance value of the image of the reproduction surface that does not include the image of the biological fine object M is checked in advance and set as a reference value (hereinafter referred to as a reference luminance value), and is compared with this value to determine whether to extract Judging.

For the luminance value, either the amplitude or the phase of the complex amplitude data (G (X, Y)) is used. In the detection of the biological fine matter M in the water as in the embodiment, it is desirable to use the phase data as a luminance value. The fine biological matter M detected by the water quality inspection system of the embodiment is often an underwater plankton such as a daphnia, and is a fine particle that is almost transparent and has a certain thickness. In the case of phase, the wavefront distortion when passing through the transparent body of microorganisms is often captured and the image is reproduced, but such wavefront distortion is likely to appear as a change in phase data. It is desirable to set a reference luminance value for and compare.

As shown in FIG. 5, the identification counting module is a subprogram that is called and executed when the average luminance value of the reproduction surface is the reference luminance value when the reproduction surface extraction module is executed. If the average luminance value on the reproduction surface is equal to or higher than the reference luminance value, the identification counting module is not executed.
The identification counting module is a module that analyzes the reproduced image on the reproduction plane P extracted as the average luminance value is less than the reference luminance value, and calculates the number of living body fine objects M. The identification counting module performs more accurate counting, that is, the viewpoint of not erroneously counting non-biological matter M, and further identifying (identifying) what kind of fine biological matter M is. A configuration optimized from the viewpoint of doing is adopted.

Specifically, the identification counting module extracts a data area that is determined to be a part of the image of the biological fine object M, and compares the extracted data area with the sample data to determine the presence of the biological fine object M. Confirmation and identification of the living body fine object M are performed. Several methods can be considered for the comparison with the sample data. In this embodiment, the comparison is performed by comparing the image data.
As shown in FIG. 9, the identification counting module reproduces an image with the extracted complex amplitude data of the reproduction surface. In this case, either amplitude or phase may be used, but an image is reproduced with amplitude data as an example. The reproduced image data is so-called image data. As shown in FIG. 8, the identification counting module processes this image data, identifies and extracts a region that is determined to show an image of the biological fine object M. This area is hereinafter referred to as an extraction area. Image data of the extraction area is indicated by I in FIG.

Then, as shown in FIG. 8, the identification counting module reads the sample data I ′ one by one from the storage unit 362 and compares it with the image data I of the extraction region. Then, the degree of coincidence between the two is determined. The degree of match is quantified in the range of 0 to 100%, and the determined degree of match is temporarily stored in a memory variable. The degree of coincidence is determined by the number of overlapping areas of the two image data I and I ′. At this time, the image data I in the extraction area is appropriately enlarged or reduced to make the size the same as the sample data I ′, or the image data I in the extraction area is rotated to make a determination in a state where the degree of matching is the highest. .

The identification counting module determines whether or not the degree of coincidence is equal to or greater than a certain threshold value, and if it is equal to or greater than the threshold value, the image data I in the extraction region represents an image of the sample data (an image of the biological fine object M). And that fact is assigned to a memory variable. For image data I of one extraction region, the number of sample data whose degree of match is greater than or equal to the threshold value is usually 0 or 1, but there may be two or more, so the identification counting module is the last sample data Comparison is performed up to I ′, and when there are a plurality of matching degrees equal to or greater than the threshold, the sample ID of the sample data with the highest matching degree is updated and stored in the memory variable. That is, in the comparison with the image data I of one extraction region, the memory variable is updated by adding 1 to the number of matches for the sample ID of the sample data having the highest matching degree that is equal to or higher than the threshold value. The memory variable here is a matrix variable (hereinafter referred to as a match number storage variable), and is a variable for substituting the number of detections for each sample data ID (hereinafter referred to as a sample ID) (initial value is zero). .

In this way, the image data I in the extraction area is determined for one extracted reproduction plane. In most cases, the number of extraction regions extracted on one reproduction plane P is only one. However, when there are two or more extraction regions, each extraction region is similarly compared with the sample data I ′, and the degree of match is If it is greater than or equal to the threshold value, the judgment result is substituted into the match number storage variable and updated. This completes the identification counting module for one reproduction plane P.

As shown in FIG. 5, when the identification counting module as the subprogram ends, the reproduction surface extraction module also ends. Since the measurement program 366 has completed the process of one example for one data set, the reproduction distance pitch is increased by ΔD, and similarly the reproduction calculation module, reproduction surface extraction determination module, and reproduction surface P are extracted. The identification counting modules are programmed to execute sequentially.
When the processing on the last reproduction surface is completed for one data set, the processing for that data set is completed. During this time, every time the degree of match exceeds the threshold value, the value of the number of detected sample IDs of the sample data is added to the match number storage variable. Note that the last reproduction plane is a reproduction plane whose reproduction distance is the final value, and is the reproduction plane having the longest reproduction distance in the set image reproduction space.

As shown in FIG. 5, the measurement program 366 performs similar data processing for the next data set. When the process for the last data set is completed, the measurement program 366 executes the output module and ends the program. When the data from the image sensor 32 is used as it is as the last data set, all the target water W to be inspected in one inspection flows in the transparent tube 1 and flows in the transparent tube 1. It becomes the data set immediately before the disappearance. In this case, the flow detection sensor 10 is provided in the transparent tube 1 as shown in FIG. 1, and when the flow detection sensor 10 is turned off, the inspection is completed, and the measurement program 366 is programmed to end. Further, when each data set is stored in the storage unit 362, when the process is completed for the last data set stored in the storage unit 362, the measurement program 366 executes the output module and ends.

In the measurement program 366, the playback distance D changes with the pitch ΔD, but there is a problem that the brightness of the playback image changes periodically when the playback distance is converted. This problem can be solved by using the technique disclosed in JP2013-148471A.

The output module displays the execution result of the measurement program 366 on the display 364. FIG. 10 is a diagram schematically illustrating an example of the execution result of the measurement program 366 by the output module. As shown in FIG. 10, the output module displays the name and number of biological fine objects M whose existence has been confirmed, together with information such as program execution date and time (inspection date and time), total flow rate (total amount of inspection), and the like. It has become.

In the measurement program 366, the reproduction calculation module and the reproduction surface extraction module (and the identification counting module that can be executed as a subprogram thereof) may be performed in parallel (that is, processed in parallel). That is, after obtaining complex amplitude data for a playback surface of a certain playback distance D, a playback surface extraction module (identification counting module that can be executed as a subprogram thereof) is executed for the playback surface, It may be programmed to perform playback calculations.

Next, the control system and the water supply system for controlling the entire system will be supplementarily described.
As shown in FIG. 1, the water quality inspection system of the embodiment includes a control unit 4 that controls the whole. The control unit 4 controls each part of the system such as the water supply system 2 and the detection system 3. This control includes opening / closing control of the valves 103 to 105 provided in the water supply system 2.

As shown in FIG. 1, an inflow control valve 103 is provided on the inflow pipe 101 between the water supply side tank 21 and the transparent pipe 1. An outflow control valve 104 is provided on the outflow pipe 102 between the transparent pipe 1 and the water-receiving side tank 22. As shown in FIG. 1, the pipe is branched upstream of the outflow control valve 104, and a bypass pipe (hereinafter, bypass pipe) 106 is provided. A bypass valve 105 is provided in the bypass pipe 106. The bypass pipe 106 is connected to the water supply side tank 21, and returns the target water W exiting the transparent pipe 1 to the water supply side tank 21.

A sequence control program is installed in the control unit 4. Hereinafter, the sequence control program will be described as well as the operation of the entire system.
The system of the embodiment is started in a state where the target water W is put in the water supply side tank 21 shown in FIG. The sequence control program first opens the inflow control valve 103 with the outflow control valve 104 closed and the bypass valve 105 open, and the pump 23 is activated in this state. As a result, the target water W flows through the transparent pipe 1 and returns to the water supply side tank 21 through the bypass pipe 106.

The sequence control program sends a measurement start control signal to the detection system 3 when it is confirmed from the output of the anemometer 24 that a predetermined flow velocity is secured. Thereby, the coherent light source 31 in the detection system 3 operates, the operation of the image sensor 32 is also started, and the number measurement of the biological fine object M by the detection system 3 is disclosed. The detection system 3 has a control unit (not shown) inside, and when it is confirmed that the output of the coherent light source 31 is stable at a predetermined value and the image sensor 32 is operating correctly, the measurement program 366 Execute.

At the start of execution of the measurement program 366, a notification to that effect is output from the control unit in the detection system 3 to the control unit 4. The sequence control program opens the outflow control valve 104 at a predetermined timing according to the flow velocity and simultaneously closes the bypass valve 105. Accordingly, the target water W flows toward the water receiving side tank 22 and is stored in the water receiving side tank 22. The timing at which the outflow control valve 104 is opened is the timing at which the target water W reaches the outflow control valve 104 as much as the number of the biological fine objects M is measured by the measurement program 366 of the detection system 3. For this reason, the target water W in which the number measurement of the biological fine matter M has been completed accumulates in the water receiving side tank 22.

When all the target water W in the water supply side tank 21 flows through the transparent tube 1 and is inspected, the output of the flow detection sensor 10 is turned off. At this time, the control unit 4 stops the operation of the pump 23 and sends a signal to the detection system 3 to stop the operation. The operation result of the detection system 3 is displayed on the display 364 as described above. The sequence control program is programmed to control each unit in the sequence as described above.

When the water quality test is performed using the water quality test system according to the above configuration, the target water W is stored in the water supply side tank 21 in advance. At this time, in order to remove relatively large dust or the like, there is a case where it is previously filtered. In addition, when turbidity is large, precipitation may be performed in advance to remove turbidity. The target water W is accommodated in the water supply side tank 21 in a state where dust and turbidity are removed as necessary, and the operation of the system is started.

The system performs detection, identification, and number calculation of the biological fine matter M in the target water W by the operation as described above, and displays the result on the display 364. The operator prints the inspection result with the printer 363 as necessary.
When the operation of the system is completed, the inspected target water W is stored in the water-receiving side tank 22. In this embodiment, since the target water W is ballast water, the target water W in the water-receiving side tank 22 is discharged to the sea as it is or if it is not a problem in the inspection result, or is stored in the ballast tank of the ship. The

According to the water quality inspection system of the embodiment related to the above configuration and operation, the inside of the pipe 1 through which the target water W flows is photographed, and measurement is performed on the spot based on the photographed data. It is suitable for testing a large amount of water in a short time.
And since imaging | photography is hologram imaging and measures the number of the biological body M in the target water W using the digital reproduction | regeneration (digital holography) of a hologram, it will test | inspect a lot of water in a short time. This is more preferable from the viewpoint.

The hologram reconstructed image is a three-dimensional image as described above, and the system of the embodiment captures an area having a depth inside the transparent tube 1 and performs one time on the three-dimensional image reconstructing space. The number of living body fine objects M is measured by photographing.
On the other hand, when considering the case where the number of the biological fine objects M is measured by the normal two-dimensional imaging, the normal two-dimensional imaging focuses on somewhere in the depth direction in the transparent tube. Even when imaging is performed and imaging is performed using an imaging optical system having a deep focal depth, the depth of the transparent tube cannot be increased so much. In other words, in normal two-dimensional imaging, the number calculation based on the analysis of imaging data cannot be performed unless the sectional area of the transparent tube is reduced and the distance in the depth direction is considerably reduced. That the cross-sectional area of the transparent tube is small means that the amount of inspection water that can be imaged at a time is small, and is not suitable for applications in which a large amount of target water W such as ballast water is inspected in a short time. . On the other hand, when the hologram is photographed and the number is calculated by analyzing the reproduced image data as in the system of the embodiment, the number can be calculated by one photographing in the three-dimensional space. It is very suitable for inspecting water W in a short time.

In the system of the embodiment, the hologram data (one data set) obtained by one imaging is not analyzed on all reproduction planes for each reproduction distance pitch ΔD, but the image of the biological fine object M is obtained. Only the reproduction surface P determined to be present is extracted and analyzed. For this reason, the time required for the inspection can be further shortened. When analysis is performed on all reproduction planes, an amplitude value map or a phase value map is generated from complex amplitude data (G (X, Y)) for each reproduction distance pitch ΔD, and an image is analyzed for either of them to create a fine living body. It is necessary to determine whether or not there is an area (extraction area) that seems to be an image of the object M, and when it is determined that there is an area, it is necessary to extract the area and compare it with sample data, which can be time-consuming data processing. . In the system of the embodiment, the measurement program 366 includes a reproduction surface extraction module, and only the reproduction surface that is determined to have an image of the biological fine object M is extracted and analyzed, so that the overall time required for data processing is greatly increased. Reduced to
In the above-described embodiment, when the average luminance value on the reproduction surface is less than the standard luminance value, the reproduction surface P is extracted as an image of the biological fine object M may be included, but other configurations may be possible. For example, the determination may be made based on whether or not the change width of the luminance value in the reproduction plane (difference between the maximum value and the minimum value of the luminance value) is a certain value or more. In the case of a certain value or more, an image of the biological fine object M can be included.

The use of specimen data for confirmation and identification of the presence of the biological fine matter M also shortens the time required for measurement, erroneous detection (counting something that is not the biological fine matter M, It is useful to prevent that it is mistakenly identified as the biological fine matter M. For identification of the living body fine object M, a configuration in which a reconstructed image is displayed on a display and appropriately enlarged or the like is performed by an operator visually is also conceivable. However, such a configuration takes too much time and is prone to errors. In the configuration of the embodiment, since analysis is performed on software by comparing sample data, there is no such problem.
In the embodiment described above, it is determined whether or not the reproduced image is an image of the biological fine object M by comparing the image data I and I ′. However, it may be determined by comparing numerical data. For example, when a certain biological fine object M has a characteristic outline and the outline can be expressed by a mathematical expression, either the amplitude or the phase of the complex amplitude data (G (X, Y)) on the reproduction surface is selected. It may be judged by looking at the correlation between the numerical value and the mathematical formula.

In addition, if it is sufficient to measure the number of living body fine objects M, and the identification is not necessary, the software configuration can be simplified. For example, when processing the image data of the extraction region as long as it can be distinguished from mere dust, it is possible to determine whether or not it is a biological fine object M only from the contour of the image. Most living body fine objects M have complicated outlines compared to dust fragments (for example, plastic garbage fragments), and the complexity of the outline is evaluated to determine whether the object is dust or the living body fine objects M. You can also.

Furthermore, in the water quality inspection system of the embodiment, it is also possible to add the life / death discrimination of the fine living body M as an inspection item. For example, many underwater microorganisms such as zooplankton, when they become dead bodies, have a shape (crumpled shape) that is crushed by water pressure. On the other hand, when it is alive, the shape is often swollen by internal body fluid. Therefore, when a hologram image of an underwater microorganism is reproduced with phase data, the distortion of the wavefront becomes larger in the case of a dead body. That is, the state of wavefront distortion can be determined by image reproduction based on phase data, and life / death determination can be performed according to the degree. In addition, some microorganisms have a characteristic shape that is different from that when they are alive, and register specimen data separately from those that are alive about the shape of such corpses, In some cases, it is possible to make a life-and-death decision based on the comparison.

In the said embodiment, although the flow rate in the transparent tube 1 was constant, it may not be constant. For example, the flow of the target water W may be intermittent, and the target water W may be in a stopped state in the transparent tube 1 when photographing in the detection system 3. Moreover, even if it does not stop, the flow is periodically slowed down, and photographing may be performed at the slow timing.
In addition, the imaging cycle has been described as the imaging width L / flow velocity V, but there may be a longer cycle. In this case, the volume Q of the imaging region × the number of imaging times T is the total amount of the inspected target water W. In this case, the inspected amount (Q · T) is smaller than the total amount of the target water W that has flowed through the pipe 1 and the total amount is not inspected, but the total amount of the target water W that has flowed is Since it can be determined by the anemometer 24 or the like, the total number of the biological fine objects W is calculated as an estimated value by proportional calculation.

Note that the imaging cycle may be synchronized with the coherent light source 31. For example, a pulsed laser light source may be employed as the coherent light source 31 and the imaging cycle may be synchronized with the pulse cycle. Further, even a continuous oscillation type is sometimes pulsed by a chopper and the imaging cycle is synchronized with this.
In the system of the above embodiment, the entire transparent tube 1 is transparent. However, it is sufficient that the transparent tube 1 can radiate coherent light and capture object light from the inside, and a part thereof is transparent like an observation window. In some cases, it is used. In addition, water may be supplied through a pipe that is all transparent.

Also, when configured as a ballast water inspection system, the water quality inspection system of the embodiment may be installed on the discharge side of the ballast water treatment apparatus and used for the purpose of checking the treated ballast water. Further, in the above embodiment, the inspected target water W is temporarily stored in the water-receiving side tank 22, but in the case of ballast water, it may be discharged into the sea as it is or may be loaded into the ballast tank as it is. obtain.

In addition, although the system of the said embodiment was a system which test | inspects ballast water as object water W, this invention should be used suitably for the test | inspection of the water used in a pool, a beach, various bath facilities, etc. Can do. Furthermore, it can also be used for the inspection of water used in seafood aquaculture facilities. For example, it can be suitably used to check for problematic parasites and bacteria.

In the above embodiment, the target water W is ballast water, and the biological microorganisms can be various zooplanktons, various phytoplanktons, eggs and larvae of various seafood, various bacteria, various algae, and the like. In addition, the water quality inspection system of the present invention can also be used for bio research and the like, and the living body fine matter M may be a biological sample or a living cell dissolved in the inspection water.

1 Piping (transparent tube)
10 Flow detection sensor 11 Observation plate 101 Piping (inflow pipe)
102 Piping (outflow pipe)
103 Inflow control valve 104 Outflow control valve 105 Bypass pipe 21 Water supply side tank 22 Water reception side tank 23 Pump 24 Current meter 3 Detection system 31 Coherent light source 32 Imaging element 33 Irradiation optical system 34 Imaging optical system 35 Reference light optical system 36 Data processing unit 361 CPU
362 Storage unit 4 Control unit W Target water M Biological fine matter P Reproduction surface

Claims (8)

1. A water quality inspection system for measuring the number of biological fines in target water,
   A water supply system that sends the target water through a pipe;
   And a detection system that detects the number of biological fines in the target water sent through the piping by the water supply system,
   The pipe has a transparent part,
   The detection system detects the number of living body fine objects by taking an image of the target water flowing in the pipe through the transparent part,
   The detection system is
   A light source that emits coherent light;
   An image sensor;
   The coherent light is irradiated into the pipe through the transparent part, the object light that is light from the target water in the pipe is guided to the image sensor through the transparent part, and the coherent light not including object information is used as the reference light. An optical system that causes the imaging device to image interference fringes by causing interference on the imaging surface of the imaging device, and
   A data processing unit that processes hologram data that is data of interference fringes imaged by the image sensor;
   The data processing unit acquires hologram data with a period according to the water supply speed in the pipe by the water supply system and the length in the water supply direction in the imaging region by the image sensor,
   The data processing unit counts the number of living body fine objects by playing back each acquired hologram data, and the number of objects determined to be images of living body fine objects at the time of image reproduction for each hologram data Water quality inspection system characterized by performing data processing to count
2. The water quality inspection system according to claim 1, wherein the data processing unit performs data processing for identifying the image of a living body fine object and counting the number.
3. Whether the data processing unit can include an image of a biological fine object according to the luminance value of the reproduction surface for each reproduction surface having a different reproduction distance for each reproduction distance pitch set when reproducing each hologram data. The data processing is carried out by extracting a reproduction surface that is determined to be included, and counting the number of the reproduction images on the reproduction surface that are determined to be images of the living body fine objects. Item 3. The water quality inspection system according to item 1 or 2.
4. 4. The water quality inspection system according to claim 3, wherein the luminance value is a phase value in a result of reproduction calculation of each hologram data.
5. The data processing unit determines whether the image obtained when reproducing each hologram data is an image of a biological fine object by comparing it with specimen data of the biological fine object, and according to the result, the number The water quality inspection system according to any one of claims 1 to 4, wherein the water quality inspection system is counted.
6. The water quality according to any one of claims 1 to 5, wherein the data processing unit is capable of counting the number of living ones after determining whether or not the image of the fine living body is viable. Inspection system.
7. The optical system includes an irradiation optical system for irradiating coherent light into the pipe and an imaging optical system for capturing object light from the target water in the pipe. The water quality inspection system according to any one of claims 1 to 6, wherein transmitted light from inside a pipe irradiated with coherent light by an optical system is captured and incident on the imaging device.
8. The water quality inspection system according to any one of claims 1 to 7, wherein the target water is a ballast water of a ship and is a ballast water inspection system.

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