Extended stereometric turbidity sensor

Abstract

The turbidity sensor is characterized by a signal processor or processing module configured to: receive a signal containing information relating to light reflected from suspended matter in a liquid and sensed by a linear sensor array having rows and columns of optical elements; and, based on the received signal, determine a corresponding signal containing information relating to the turbidity concentration of the liquid.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of provisional patent application serial number 63 / 027,587 (911-023.9-1-1 / N-YSI-0045US01) filed on May 20, 2020, 63 / 028,013 (911-023.010-1-1 / N-YSI-0046US02) filed on May 21, 2020, and 63 / 028,723 (911-023.011-1-1 / N-YSI-0047US02) filed on May 22, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to sensors for measuring water quality; and more particularly to turbidity sensors for measuring water quality. Background Technology

[0004] Traditional turbidity sensing techniques suffer from poor sensitivity (especially for field-deployable sensors) due to inefficient or poor capture of the scattered signal (solid angle). Existing turbidity sensors typically employ a single excitation source utilizing a photosensitive element and a single or point-like emitter-receiver. Regardless of the specific photosensitive element or excitation source used, current turbidity sensors known in the art are not optomechanically configured for effective capture of the solid angle, thus compromising the turbidity detection limit.

[0005] The difficulty in measuring scattering-based signals lies in the spatial / directional nature of randomly scattered light radiation. Now consider the excitation of a single turbid particle. For typical environmental water quality monitoring conditions, the spatial distribution of the scattered radiation from a single turbid particle is well approximated by a sphere, resulting in a 4π [steradian] solid angle of the scattered radiation (see...). Figure 1 To optimally capture such turbidity signals, a photosensitive area closely matched to the radiation pattern is required; that is, a photosensitive area in the shape of a spherical shell. See also Figure 1 Therefore, there is a need in this field for better turbidity sensors.

[0006] Furthermore, and for example, PCT / US2008 / 059575, filed April 7, 2008, entitled "System and method for high-throughput turbidity measurements," discloses a technique for turbidity measurement using a spatial gradient method. The turbidity measurement system includes: a sample assembly containing multiple samples; a light source illuminating the sample assembly; and a light detection system comprising a two-dimensional photosensitive array. The photosensitive array is simultaneously exposed to light transmitted through each sample in the sample assembly. The exposures are analyzed to determine the average transmitted light intensity of each sample, and the turbidity value of each sample is calculated based on its average transmitted light intensity. Multiple exposures can be performed during the measurement period to obtain time-resolved turbidity measurements of the samples. The temperature of the samples can be varied during the measurement period to measure turbidity based on temperature. Summary of the Invention

[0007] In summary, the purpose of this invention is to greatly increase the captured solid angle, thereby significantly improving the sensitivity of turbidity measurement.

[0008] The sensor under consideration incorporates many features present in an idealized elongated cylindrical geometry (within the practical range of sensors for field control). The invention employs a linear photodiode array (the proposed method is not limited to photodiode technology; for example, linear CCD or CMOS arrays could also be used). The linear array allows ample space for biocontamination countermeasures such as motorized wiping. Additionally, linear sensor arrays are currently available as relatively inexpensive commercial off-the-shelf (COTS) components.

[0009] The key specific aspect of this invention lies in the optomechanical configuration, which utilizes a wide linear array along the length of the quasi-collimated light source to enhance signal capture. Additionally, this design allows for the capture of backscattered radiation—all in a single embodiment.

[0010] This design is compatible with non-intensity-based turbidity determination. These measurements are spatially correlated, and the main idea is that the optical signal will undergo attenuation across a linear array following Beer's Law, thus creating a "spatial gradient." This spatial gradient contains information related to turbidity concentration.

[0011] Measurements based on non-intensity are unaffected by the "drift" of the excitation source. In other words, the spatial gradient is unaffected by modest changes in the intensity of the excitation source (e.g., LED intensity degradation during use) or changes in optical power due to thermal effects.

[0012] The "spatial gradient" method according to the present invention enables real-time, internal filtering effect (IFE) correction, which greatly enhances the sensing range for high concentrations. (In contrast, known techniques for internal filtering correction involve post-processing via laboratory analysis after field deployment.)

[0013] Additionally, the “spatial gradient” method according to the invention also allows for certain types of disturbance correction that cannot be achieved using amplitude-based techniques known in the art.

[0014] The aforementioned "spatial gradient" method requires that each optical element in the array be individually addressable. However, there are possible design variations involving connecting all linear array elements in a parallel configuration, which would preclude the possibility of individual addressability. However, such a design variation can be modified to include a transmission photodiode (located at the end of the array, opposite the source), which would restore the sensor's ability to perform drift and IFE corrections.

[0015] According to some embodiments, the present invention may include or employ means characterized by a signal processor or processing module, the signal processor or processing module being configured to:

[0016] Receive signaling containing information relating to light reflected from suspended matter in the liquid and sensed by a linear sensor array having rows and columns of optical elements; and

[0017] Based on the received signaling, determine the corresponding signaling that contains information related to the concentration parameters of the liquid.

[0018] The device may include one or more of the following additional features:

[0019] Parameters can include liquid turbidity.

[0020] The device may include a linear sensor array.

[0021] Linear sensor arrays can include linear photodiode arrays.

[0022] Linear sensor arrays can include linear CCD arrays.

[0023] Linear sensor arrays can include linear CMOS arrays.

[0024] Linear sensor arrays can include closed cylindrical sensor arrays, which are three-dimensional cylindrical arrays with rows and columns of optical elements.

[0025] The device can be a turbidity sensor.

[0026] The device may include a pseudo-collimated light source having a certain length and configured to provide light, including pseudo-collimated light, along the corresponding length of the linear sensor array.

[0027] The signal processor or processing module can be configured to determine parameters based on the attenuation of the optical signal sensed by the translinear sensor array.

[0028] Linear sensor arrays may include arrays of individually addressable two-dimensional optical elements.

[0029] The signal processor or processing module can be configured to determine turbidity based on the spatial gradient of the optical signal sensed by the translinear sensor array, the spatial gradient containing information related to turbidity concentration.

[0030] Optical elements can be addressed individually by a signal processor or processing module.

[0031] The rows or columns of optical elements can be connected in parallel and are addressable by a signal processor or processing module; the device may include a transmission photodiode located at the end of a linear sensor array opposite to the light source, the transmission photodiode being configured to respond to light reflected from suspended matter and provide transmission photodiode signaling containing information related to the suspended matter; and the signal processor or processing module may be configured to receive the photodiode signaling and correct the corresponding signaling for drift or internal filtering effects.

[0032] According to some embodiments, the present invention may include a turbidity sensor characterized by a pseudo-collimated light source, a linear sensor array, and a signal processor or processing module. The pseudo-collimated light source has a length and can be configured to provide pseudo-collimated light to a liquid sample. The linear sensor array may include rows and columns of optical elements and is configured to sense light reflected from suspended matter in the liquid sample along the length of the pseudo-collimated light source and provide signaling containing information related to the light reflected from the suspended matter.

[0033] The signal processor or processing module can be configured as follows:

[0034] Receive signaling; and

[0035] Based on the received signaling, determine the corresponding signaling that contains information related to the turbidity concentration of the liquid.

[0036] The turbidity sensor may also include one or more of the features described above.

[0037] method

[0038] According to some embodiments, the present invention may include a method, characterized in that:

[0039] Using a signal processor or processing module, signaling is received, the signaling containing information relating to light reflected from suspended matter in the liquid and sensed by a linear sensor array having rows and columns of optical elements; and,

[0040] Based on the received signaling, a signal processor or processing module is used to determine the corresponding signaling containing information related to the concentration of parameters of the liquid.

[0041] The method may also include one or more of the features mentioned above.

[0042] Computer-readable storage media

[0043] According to some embodiments of the present invention, the present invention can also take the form of a computer-readable storage medium having computer-executable components for performing the steps of the methods described above. The computer-readable storage medium may also include one or more of the features described above.

[0044] advantage

[0045] This invention offers significant advantages over currently known technologies in the prior art, as follows:

[0046] 1) Optimized solid angle capture significantly enhances signal sensitivity, thereby substantially improving the minimum limit of turbidity detection. Linear sensor arrays provide a much larger total effective area for capturing scattered rays. More importantly, the effective area is larger along the direction of the quasi-collimated excitation source, in the most important dimension. Additionally, for the reasons mentioned above, a wider linear array is preferably built on a thinner linear array to increase the effective area. However, there is a limitation of diminishing returns with respect to width; that is, an array width that does not roughly match the diameter of the excitation beam is non-ideal.

[0047] 2) This invention enables the measurement of backscattered radiation (in addition to radially emitted lateral scattering) – all within a single sensing embodiment.

[0048] 3) The distance between the quasi-columnar excitation source and the linear sensor array is minimized, as this enhances sensitivity in addition to sensing range. Attached Figure Description

[0049] Attached figures that are not necessarily drawn to scale include Figures 1-6B ,as follows:

[0050] Figure 1 It is a diagram of the spatial distribution of scattered radiation from a single turbid particle approximated by a sphere, which produces a 4π [steradian] solid angle of scattered radiation known in the art.

[0051] Figure 2AThis is a block diagram of an apparatus including a turbidity sensor according to some embodiments of the present invention.

[0052] Figure 2B This is a block diagram of a linear sensor array with rows and columns of optical elements according to some embodiments of the present invention.

[0053] Figure 3 This is a three-dimensional perspective view of a pseudo-collimated light source that provides pseudo-collimated light relative to a linear sensor array according to some embodiments of the present invention.

[0054] Figure 4 yes Figure 3 The side view shown illustrates backscattered radiation captured by a linear sensor array according to some embodiments of the invention.

[0055] Figure 5 This is a graph showing the relative sensor response to relative concentration. For example, it shows a sensitivity comparison between the transferee's current EXO turbidity sensor (solid line with dots) and a linear array turbidity sensor (solid line). Note that this graph shows simulation data based on a physical model designed according to the present invention.

[0056] Figure 6A It is an isometric view showing a solid angle capture of a three-dimensional drawing according to the invention for an idealized elongated cylindrical shell geometry (e.g., such as a 3-D cylindrical linear sensor array).

[0057] Figure 6B It is a cross-sectional view showing an idealized elongated cylindrical shell geometry (such as a 3-D cylindrical linear sensor array).

[0058] To reduce clutter in the accompanying figures, each figure need not include every figure label for every element shown therein. Detailed Implementation

[0059] Figure 2 shows a device 10 according to the present invention, which includes a turbidity sensor having a pseudo-collimated light source 20, a linear sensor array 30, and a signal processor or processing module 40.

[0060] The signal processor or processing module 40 can be configured as follows:

[0061] The system receives a signaling message containing information relating to light Lr reflected from suspended matter in the liquid and sensed by a linear sensor array 30, which has rows and columns of optical elements (r1, c1; r1, c2; r1, c3; r1, c4; r1, c5; r1, c6; r1, c7; r1, c8; ...; r1, c1; r2, c1; r2, c2; r2, c3; r2, c4; r 2,c5;r2,c6;r2,c7;r2,c8;…;r2,cn;r3,c1;r3,c2;r3,c3;r3,c4;r3,c5;r3,c6;r3,c7;r 3,c8;…;r3,cn;…;rn,c1;rn,c2;rn,c3;rn,c4;rn,c5;rn,c6;rn,c7;rn,c8;…;rn,cn); and

[0062] The corresponding signaling, which contains information related to the concentration of parameters of the liquid, is determined based on the received signaling.

[0063] parameter

[0064] For example, the parameter may include the turbidity concentration in the liquid, and the device may be a turbidity sensor or take the form of a turbidity sensor. However, the scope of the invention is not limited to any particular type or kind of parameter that is sensed in a liquid, whether now known or to be developed in the future.

[0065] Linear sensor array 30

[0066] For example, device 10 may include a linear sensor array 30, such as a linear photodiode array, a linear charge-coupled device (CCD) array, or a linear CMOS array. Specifically, for example, Figure 2B As shown, the linear sensor array 30 may comprise a two-dimensional array of rows and columns of individually addressable optical elements. Linear sensor arrays are known in the art, and the scope of the invention is not limited to any particular type or kind now known or to be developed in the future.

[0067] For example, linear sensor arrays are disclosed in the following U.S. Patent Nos. 9,020,202; 8,022,349; 7,956,341; 7,040,538; 5,252,818 and 4,193,057, the entire contents of which are incorporated herein by reference.

[0068] Figure 3 and Figure 4

[0069] As an example, device 10 may include a source 20 configured to provide light Lc along a corresponding length of linear sensor array 30 (e.g., as shown in Figures 2 and 3), light Lc comprising quasi-collimated light, such as light Lr reflected from suspended matter in a liquid sample being monitored or tested onto the linear sensor array 30 by means of a liquid sample arranged relative to the source 20 and the linear sensor array 30. For example, light Lr may be radially reflected ( Figure 3 ) and reverse reflection ( Figure 4 That is, backscattered reflected light or radiation.

[0070] As those skilled in the art will understand, pseudo-collimated light sources are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind now known or to be developed in the future.

[0071] Figure 4 The backscattered radiation captured by the linear sensor array 30, consistent with that shown, is illustrated, where backscattered radiation is understood as light reflected by suspended matter in the liquid sample and traveling in the opposite direction.

[0072] Signal processor or processing module 40

[0073] For example, the signal processor or processing module 40 may be configured to determine parameters, including turbidity, based on the attenuation of the optical signal sensed by the translinear sensor array (which includes its length and width). Techniques for sensing the attenuation of optical signals (e.g., related to the turbidity concentration in a liquid) are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind now known or to be developed in the future.

[0074] For example, the signal processor or processing module 40 may be configured to determine turbidity concentration based on the spatial gradient of the optical signal sensed by the translinear sensor array. As those skilled in the art will understand, techniques for determining turbidity concentration in a liquid based on the spatial gradient of an optical signal are known in the art, for example, consistent with PCT / US2008 / 059575 described herein, the entire contents of which are incorporated herein by reference, and the scope of the invention is not intended to be limited to any particular type or kind of technique now known or to be developed later.

[0075] In an alternative embodiment, rows or columns of optical elements may be connected in parallel and may be addressed by a signal processor or processing module 40; the device 10 may include a transmission photodiode 30a located at the end of the linear sensor array 30 opposite to the light source 20, the transmission photodiode 30a being configured to respond to light L reflected from the suspended matter and provide transmission photodiode signaling containing information related to the suspended matter; and the signal processor or processing module 40 may be configured to receive the photodiode signaling and correct the corresponding signaling for drift or internal filtering effects.

[0076] How to implement signal processing functions

[0077] For example, the functionality of the signal processor or processing module 40 can be implemented using hardware, software, firmware, or a combination thereof. In a typical software implementation, the signal processor 40 will include an architecture based on one or more microprocessors, having, for example, at least one signal processor or microprocessor. Those skilled in the art will be able to program implementations such as microcontroller-based or microprocessor-based implementations with appropriate program code to perform the signal processing functions disclosed herein without much experimentation.

[0078] The scope of this invention is not intended to be limited to any particular implementation using techniques now known or to be developed in the future. The scope of this invention is intended to include implementing the functionality of (multiple) signal processors as independent processors, signal processors or signal processor modules, as well as individual processors or processor modules and some combination thereof.

[0079] As an example, as those skilled in the art will understand, the device 10 may also include other signal processor circuitry or components, such as those generally indicated by 50, including random access memory or memory modules (RAM) and / or read-only memory (ROM), input / output devices and controls, and data and address buses connected thereto and / or at least one input processor and at least one output processor.

[0080] As another example, the signal processor may include or take the form of a combination of a signal processor and at least one memory, the at least one memory including computer program code, wherein the signal processor and at least one memory are configured to cause the system to perform the functions of the present invention, for example, responding to received signaling and determining corresponding signaling based on the received signaling.

[0081] Figure 6A and Figure 6B 3D cylindrical linear sensor array 60

[0082] For example, device 10 may include a closed cylindrical sensor array 60, which has, for example, the following characteristics: Figure 6A The optical elements shown are arranged in a three-dimensional cylindrical array of rows and columns with a length L.

[0083] exist Figure 6A In this configuration, the 3D cylindrical linear sensor array 32 is configured to capture light reflected from suspended matter in the liquid radially 360 degrees along its length L and around its longitudinal axis.

[0084] As those skilled in the art will understand, common / practical light sources, including LEDs, laser diodes, or broadband lamps, are typically configured to provide a columnar or quasi-columnar optical radiation pattern, for which the ideal photosensitive area takes the shape of a long, columnar shell to capture rays perpendicular to the excitation column. According to the inventors at the time of filing this patent application, there is no commercially available “closed cylindrical” sensor array.

[0085] Internal filtering effect (IFE)

[0086] As those skilled in the art will understand, IFE is a fluorescence spectroscopy phenomenon, for example, the reduced fluorescence emission observed in concentrated solutions due to the absorption of excitation light by fluorophores near the incident beam, and it significantly reduces the light that reaches the sample and then moves further away from the sample.

[0087] As those skilled in the art will understand, the techniques for correcting IFE are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind now known or to be developed in the future.

[0088] application

[0089] The present invention has applications, for example, in water quality monitoring for freshwater applications (e.g., where turbidity is one of the "five parameters") and in basic parameters for drinking water monitoring.

[0090] Scope of the Invention

[0091] While the invention has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made without departing from the scope of the invention, and equivalents can be used to replace its elements. Additionally, modifications can be made to adapt particular situations or materials to the teachings of the invention without departing from the basic scope of the invention. Therefore, the invention is not limited to the specific embodiments disclosed herein as the best mode for carrying out the invention.

Claims

1. An apparatus comprising: The signal processor or processing module is configured as follows: Receive signaling containing information relating to light reflected from suspended matter in a liquid and sensed by a linear sensor array having length and multiple rows and columns of optical elements; as well as Based on the received signaling, a corresponding signaling is determined, the corresponding signaling containing information related to the parameter concentration of the liquid, the parameter concentration depending on the spatial gradient of the light reflected and sensed along the length of the linear sensor array.

2. The apparatus according to claim 1, wherein the parameter is the turbidity of the liquid.

3. The apparatus of claim 1, wherein the apparatus comprises the linear sensor array.

4. The apparatus of claim 3, wherein the linear sensor array comprises a linear photodiode array.

5. The apparatus of claim 3, wherein the linear sensor array comprises a linear CCD array.

6. The apparatus of claim 3, wherein the linear sensor array comprises a linear CMOS array.

7. The apparatus of claim 3, wherein the linear sensor array comprises a closed cylindrical sensor array having a three-dimensional cylindrical array of the multiple rows and columns of optical elements.

8. The apparatus according to claim 1, wherein the apparatus is a turbidity sensor.

9. The apparatus of claim 1, wherein the apparatus includes a pseudo-collimated light source having a length and configured to provide light comprising pseudo-collimated light along a corresponding length of the linear sensor array.

10. The apparatus of claim 1, wherein the signal processor or processing module is configured to determine the parameters based on the attenuation of the optical signal sensed across the linear sensor array, wherein "across the linear sensor array" includes the length and width along the linear sensor array.

11. The apparatus of claim 1, wherein the linear sensor array comprises an array of individually addressable two-dimensional optical elements.

12. The apparatus of claim 1, wherein the optical element is individually addressable by the signal processor or processing module.

13. The apparatus according to claim 9, wherein, The multiple rows of optical elements or the multiple columns of optical elements are connected in parallel and can be addressed by the signal processor or processing module; The device includes a transmission photodiode located at the end of the linear sensor array opposite the quasi-collimated light source, the transmission photodiode being configured to respond to light reflected from the suspended matter and to provide transmission photodiode signaling containing information related to the suspended matter; and The signal processor or processing module can be configured to receive the photodiode signaling and correct the corresponding signaling for drift or internal filtering effects.

14. A method comprising: Using a signal processor or processing module, a signaling message is received containing information relating to light reflected from suspended matter in a liquid and sensed by a linear sensor array having length and multiple rows and columns of optical elements; as well as Based on the received signaling, the signal processor or processing module determines a corresponding signaling containing information related to the parameter concentration of the liquid, the parameter concentration depending on the spatial gradient of the light reflected and sensed along the length of the linear sensor array.

15. The method of claim 14, wherein the parameter is the turbidity of the liquid.

16. The method of claim 14, wherein the method includes configuring the linear sensor array as a linear photodiode array, a linear CCD array, or a linear CMOS array.

17. The method of claim 14, wherein the method comprises configuring the linear sensor array as a closed cylindrical sensor array having the three-dimensional cylindrical array of the multiple rows and columns of optical elements.

18. The method of claim 14, wherein the method includes determining the parameter based on the attenuation of the optical signal sensed across the length of the linear sensor array.

19. The method of claim 14, wherein the method comprises configuring a light source to provide the light, providing the light comprising: Use a pseudo-collimated light source to provide pseudo-collimated light.

20. A turbidity sensor, comprising: A pseudo-collimated light source, having a length, is configured to provide pseudo-collimated light to a liquid sample; A linear sensor array having multiple rows and columns of optical elements, configured to: sense light reflected from suspended matter in the liquid sample along the length of the quasi-collimated light source, and provide signaling containing information relating to the light reflected from the suspended matter, and The signal processor or processing module is configured as follows: Receive the signaling; as well as Based on the received signaling, a corresponding signaling is determined containing information related to the turbidity concentration of the liquid, which depends on the spatial gradient of the light reflected and sensed along the length of the pseudo-collimated light source.

21. The turbidity sensor according to claim 20, wherein the linear sensor array comprises a linear photodiode array, a linear CCD array, or a linear CMOS array.

22. The turbidity sensor of claim 20, wherein the signal processor or processing module is configured to determine the turbidity based on the attenuation of an optical signal sensed across the linear sensor array, wherein "across the linear sensor array" includes the length and width along the linear sensor array.

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