CN107860766A - Dry chemical method accurate detection device and method based on color sensor - Google Patents

Abstract

The invention relates to a color sensor-based precise detection device and method for dry chemical method, relates to the technical field of color recognition, and is an instrument device for color recognition of dry chemical method test strips and determination of the concentration of analyte by using color recognition technology. Aiming at the disadvantages of dry chemical method detection, an accurate color recognition device based on a color sensor is provided, which can realize accurate quantification of dry chemical method. The invention is composed of a test strip measuring unit, an LED light source assembly, a color sensor unit, a communication unit, a control unit and other main parts. At the same time, a method for establishing a quantitative relationship model between color and the concentration of the analyte, and a quantitative method for unknown substances were also invented.

Description

Device and method for accurate detection of dry chemical method based on color sensor

technical field

The invention belongs to the technical field of color recognition, and relates to an instrument device which utilizes color recognition technology to carry out color recognition on dry chemical method test strips and determine substance concentrations.

Background technique

The dry chemical method refers to adding the liquid detection sample directly to the dry reagent strip specially made for different projects, and using the moisture of the tested sample as the solvent to make the chemical components in the sample react with the chromogenic substance on the reagent strip to produce a specific chemical reaction. A method of chemical analysis that changes color. The dry chemical method can realize the detection of various chemical components or biological substances, and is widely used in many fields such as food safety, environmental sanitation, and clinical testing. The dry chemical method mainly has the following characteristics: high accuracy and fast speed, and the test result can be obtained within 3 to 4 minutes; easy to operate and does not require daily calibration; no need to store any other reagents or prepare any solutions; no pretreatment of samples is required , The multi-layer membrane of the test strip has the function of selective filtration, thereby reducing the influence of interfering substances in the determination process; the amount of specimen is small, and the water in the reaction is supplied by the liquid component in the specimen, which improves the sensitivity of the determination.

In the previous dry chemical method, the color comparison between the test strip and the standard color card was carried out by human eyes to realize the semi-quantitative analysis of the substance to be tested. Due to the color resolution ability of the human eye, the color accuracy of the color chart, and the influence of environmental light and other factors, it is difficult to achieve accurate quantitative analysis. Especially for the detection of some analyte substances with extremely small changes in the color range, dry chemical methods are difficult to implement.

Contents of the invention

The invention mainly aims at the disadvantages of dry chemical method detection, provides an accurate color recognition device, and provides a method for establishing the quantitative relationship between the color and the concentration of the substance to be tested.

In order to achieve the above object, the present invention provides a color sensor-based precise detection device for dry chemical method - a color recognition device.

The accurate detection device based on the color sensor dry chemical method includes a test strip measurement unit, an LED light source assembly, a color sensor unit, a communication unit and a control unit. The sensor unit uses RGB (red, green, blue) three-color color sensors to detect the color of the test strip, and the control unit uses the ARM microprocessor as the core to form a detection system for accurate measurement of the color of the dry chemical method test strip. instrument. in:

The test strip measurement unit includes a light-tight measurement chamber, the test strip is placed in the measurement chamber, the LED light source is installed at the position where the light irradiates the test strip, and the RGB color sensor is installed at the position where the test strip can be detected. The position of the note color.

The measuring chamber is provided with a hollow chamber for placing test strips, two cylindrical passages are connected above the measuring chamber, and the top of the cylindrical passage is used for installing LED light sources.

The length of the circular channel is 0.5CM-1CM, and it forms an angle with the plane of the measuring chamber, and its axis points to the center of the test strip;

A square interface is provided above the measurement chamber for installing RGB color sensors. The front part of the measuring chamber is provided with a rectangular opening for putting the test strips in, a movable lock is provided inside the rectangular opening, and guide rails are provided at the bottom of the measuring chamber for stably putting the test strips in.

The above-mentioned accurate detection device based on the dry chemical method of the color sensor, the LED light source assembly includes an LED light source and an LED light intensity control circuit electrically connected to it to control the light intensity of the LED light source; the color sensor unit includes RGB color sensors and A color sensor control circuit electrically connected to it; the control unit includes a microprocessor, connected to the color sensor control circuit, the color sensor control circuit and the communication unit, receives a detection command from the control terminal through the communication unit, and uses the LED light intensity control circuit to The LED light source outputs a light signal with appropriate intensity, the color sensor is controlled to collect the color signal, and after white balance correction, it is transmitted to the control terminal through the communication unit.

The communication unit is a bluetooth module.

The present invention also provides a method for establishing a quantitative model of the relationship between color and concentration based on a color sensor, using the aforementioned dry chemical method based on a color sensor for accurate detection, comprising the following steps:

Step a: Place a pure white test strip in the cavity of the measuring chamber, control the LED light source to emit light of appropriate intensity (so that the color sensor detection value is about 80% of the maximum output value) to irradiate the test strip, and then pass through the color sensor Detect the scattered light to obtain the original white balance color data, and normalize the original data according to the principle of the same intensity of the pure white RGB three primary colors, and calculate the respective white balance conversions of the RGB three primary colors (red R, green G, blue B) factor;

Step b: Place the dry chemical method test strip (shown in color) that has tested samples of different standard concentrations in the measurement room, control the LED light source to emit light with the same intensity as that used in the previous step to irradiate the test strip, and then pass the color The sensor detects the scattered light, and obtains the original color data corresponding to the dry chemical method test strips of samples with different standard concentrations, and multiplies the R, G, and B original data by their respective white balance conversion factors to obtain the R, G, and B white balance correction data;

Step c: Convert the white balance correction data R, G, and B after white balance correction to HSL (hue H, saturation S, lightness L) or HSV (hue H, saturation S', lightness V) according to the following formula color space:

Let max be equivalent to the largest of the white balance correction data R, G, and B, and let min be equal to the smallest of these values. The formula for converting R, G, and B to H, S, and L is as follows:

Hue H in HSV and HSL has the same definition and algorithm. The values of saturation S’ and lightness V in HSV are defined as follows:

Step d: According to different color changes, establish any of the following quantitative relationship models for the relationship between color and component concentration:

If the color and hue of the test paper change with the concentration change, establish the relationship model between concentration and H;

If only the saturation of the color of the test paper changes with the concentration, then establish a relationship model between the concentration and S or S';

Or a model of the relationship between concentration and multivariate variables in HSL or HSV.

The present invention further provides a method for determining the concentration of components in a sample based on a color sensor, using the quantitative model of the relationship between color and concentration established by the above method, and further implementing the following steps:

Step e: Place the dry chemical method test strip of the unknown concentration sample in the cavity of the measurement chamber, control the LED light source to emit light with the same intensity as step a to irradiate the test strip (color has been displayed), and then detect the scattered light through the color sensor , to obtain the original color data corresponding to the unknown concentration sample, multiply the unknown concentration sample R, G, B original data by the white balance conversion factor, and obtain the unknown concentration sample R, G, B white balance correction data;

Step f: Convert the R, G, and B data of the unknown density sample after step e white balance correction to HSL or HSV color space in the same way as step c;

Step g: Substituting the converted data in step f into the quantitative relationship model determined in step d, and calculating the concentration of the component in the unknown concentration sample.

The present invention adopts above-mentioned technical scheme to have following advantage:

1. Using a color sensor for color measurement and establishing a quantitative relationship can give more accurate dry chemical method measurement results;

2. White light LED is used as the light source, and low-power Bluetooth is used for communication, which makes the instrument small in size, low in power consumption, and has no moving parts, which is conducive to the miniaturization and intelligence of the instrument, and the method is convenient for the instrument to be used in various scenarios . The hardware part of the instrument is composed of test strip measurement unit, LED light source assembly, color sensor unit, communication unit, control unit and other parts.

Description of drawings

Fig. 1, the hardware structural principle block diagram of the present invention;

Fig. 2, the structural representation of pilot test strip measuring unit of the present invention;

Fig. 3, the principle block diagram of the hardware structure of the control unit of the present invention;

Fig. 4, flow chart of analysis method of the present invention;

Fig. 5, the data fitting diagram of the nitrite measurement result of the present invention.

Detailed ways

Specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Example 1

The accurate detection device of the dry chemical method based on the color sensor of the present invention has a block diagram of its hardware structure as shown in Figure 1, including a test strip measurement unit, an LED light source assembly, a color sensor unit, a control unit, a communication unit and a control terminal. The invention adopts the intensity continuously adjustable white light LED as the light source, uses the RGB (red, green, blue) three-color color sensor to detect the color of the test strip, and takes the ARM microprocessor as the core to form a precise color measurement system for the chemical method test strip. Testing equipment.

Wherein: as shown in Figure 2, the test strip measurement unit is mainly composed of a light-tight square measurement chamber 1, the measurement chamber 1 is a hollow chamber, and two cylindrical passages 2, 3 are connected above it, and the cylindrical The top of the cylindrical channel 2 and 3 is used to install the LED light source, and the light is directly introduced into the measurement room through the cylindrical channel and irradiated on the test strip to be tested in the measurement room; there is also a square interface 4 on the top of the measurement room 1 for installation RGB color sensor; the front part of the measurement chamber 1 is provided with a rectangular opening 5 for putting the test paper strips in, and the bottom of the inner cavity of the measurement chamber 1 has a corresponding guide rail structure design to ensure the stability and stability of the test paper placed in the measurement chamber 1 repeatability.

The length of the circular passages 2 and 3 of the measurement chamber 1 is usually 0.5CM to 1CM, and it forms a certain angle with the upper plane of the measurement chamber, and its axis points to the center of the test strip; this can effectively ensure that the LED light source irradiates the test strip. At the same time, there will be no light directly irradiating the RGB sensor to affect the accuracy of the detection results.

The LED light source assembly is mainly composed of an existing LED light source and an LED light intensity control circuit electrically connected to it. The LED light source is installed on the top of the cylindrical channels 2 and 3, and the LED light intensity control circuit is connected to the control unit of the control unit. In the circuit; the LED light source is a white light LED, and its intensity is adjusted by the light intensity control circuit. The intensity of the LED light source installed in the two channels can be controlled to be the same or different, so that the RGB color sensor is in the best detection range. The light intensity control circuit generates different LED control voltages by adjusting the square waves output by the control unit with different duty ratios, so as to realize the adjustment of the intensity of the LED light source.

The color sensor unit is mainly composed of an existing RGB color sensor and a color sensor control circuit electrically connected to it; the color sensor is installed in the square interface 4 above the measurement chamber 1, and the color sensor control circuit is connected to the control unit. In the control circuit; the color sensor can use the TCS3200 device, and different measurement channels can be opened through the color sensor control circuit to realize the detection of the three colors of RGB respectively. The color sensor outputs a frequency signal proportional to the color intensity, and the signal directly passes through the control unit. Carry out frequency counting to realize color detection.

The communication unit can be a low-power bluetooth module; the instrument can adopt a module supporting bluetooth 4.1 and above protocols, and the bluetooth module is connected to the control unit through the serial port protocol; the instrument is connected to the remote control terminal through the bluetooth communication protocol , the remote control terminal can be a smart phone, a tablet computer, a personal computer or a dedicated control device that supports the Bluetooth communication protocol;

The control unit can be a control circuit installed in any suitable position on the periphery of the measurement chamber 1. FIG. 3 shows a block diagram of the hardware structure of the control unit, which includes a microprocessor, a color sensor control circuit, and an LED controller light source control circuit. And the bluetooth module, with the general-purpose microprocessor as the core, its model can adopt the LPC213X series microprocessor with the ARM as the core.

The control terminal, which may not be in contact with the instrument body, can be a smart phone, a tablet computer, a personal computer or a dedicated control device supporting the bluetooth communication protocol; the control unit receives the detection command from the control terminal through a communication unit (such as a bluetooth module), Through the LED light intensity control circuit, the LED light source outputs a light signal with appropriate intensity, the color sensor is controlled to collect the color signal, and after white balance correction, it is transmitted to the control terminal through the communication unit. The control terminal first converts the RGB color space model into an HSV color space model, and calculates the concentration of the analyte by selecting the quantitative relationship of the analyte, and displays it on the control terminal.

The precise detection device of the dry chemical method based on the color sensor of the present invention is obtained through the assembly of the above several parts. The quantitative detection of the concentration of the substance to be tested in the sample can be realized by using the color recognition device.

Example 2

The present invention quantitatively detects the concentration of the substance to be tested in the sample by establishing the quantitative relationship between the color and the concentration, so as to obtain the concentration of the substance to be tested by identifying the colors of various dry chemical method test strips. The method for establishing the quantitative relationship between color and concentration includes the following steps (Figure 4):

Step a: Place a pure white test strip in the cavity of the measuring chamber, control the LED light source to emit light of appropriate intensity (so that the color sensor detection value is about 80% of the maximum output value) to irradiate the test strip, and then pass through the color sensor Detect the scattered light to obtain the original white balance color data, and normalize the original data according to the principle of the same intensity of the pure white RGB three primary colors, and calculate the respective white balance conversions of the RGB three primary colors (red R, green G, blue B) factor.

Step b: Place the dry chemical method test strip (shown in color) that has tested samples of different standard concentrations in the measurement room, control the LED light source to emit light with the same intensity as that used in the previous step to irradiate the test strip, and then pass the color The sensor detects the scattered light, and obtains the original color data corresponding to the dry chemical method test strips of samples with different standard concentrations, and multiplies the R, G, and B original data by their respective white balance conversion factors to obtain the R, G, and B white balance correction data;

Step c: Convert the white balance correction data R, G, and B after white balance correction to HSL (hue H, saturation S, lightness L) or HSV (hue H, saturation S', lightness V) according to the following formula color space:

Let max be equivalent to the largest of the white balance correction data R, G, and B, and let min be equal to the smallest of these values. The formula for converting R, G, and B to H, S, and L is as follows:

The hue H in HSV and HSL has the same definition and algorithm, but the other components are different. The values of saturation S' and lightness V in HSV are defined as follows:

Step d: Establish a quantitative relationship model according to the change of different colors. If the color and hue of the test paper change with the concentration, then establish the relationship model between the concentration and H; if the test paper only changes in the color saturation with the concentration change, then establish the relationship model between the concentration and S or S'; you can also establish the concentration according to the needs Relationship models with multivariate variables in HSL or HSV.

Based on the quantitative relationship between color and concentration determined above, the present invention also provides a measurement step for unknown samples. After the quantitative relationship of concentration is established, the unknown sample test is carried out according to the following steps:

Step e: Place the dry chemical method test strip of the unknown concentration sample in the cavity of the measurement chamber, control the LED light source to emit light with the same intensity as step a to irradiate the test strip (color has been displayed), and then detect the scattered light through the color sensor , to obtain the original color data corresponding to the unknown concentration sample, multiply the unknown concentration sample R, G, B original data by the white balance conversion factor, and obtain the unknown concentration sample R, G, B white balance correction data;

Step f: Convert the R, G, and B data of the unknown concentration sample after step e white balance correction to HSL or HSV color space in the same way as step C;

Step g: Substituting the converted data into the quantitative relationship model determined in step d, and calculating the concentration of the component in the sample with unknown concentration.

Embodiment 3 establishes the quantitative relationship model between color and concentration

The following uses the nitrite dry chemical method as a specific example to illustrate the method of establishing the quantitative relationship between color and concentration:

Test samples: standard solutions of nitrite with different concentrations.

Operation process: put Changchun Jida Little Swan Instrument Co., Ltd. nitrite rapid detection test strip in the nitrite standard solution for color development, and then operate as follows:

Step a: Place a pure white test strip in the cavity of the measuring chamber, control the LED light source to emit light of appropriate intensity (so that the color sensor detection value is about 80% of the maximum output value) to irradiate the test strip, and then pass through the color sensor Scattered light is detected to obtain the original white balance color data. According to the principle of the same intensity of pure white RGB three primary colors, the original data is normalized, and the white balance conversion factors of R, G, and B three primary colors are calculated.

Step b: Place the dry chemical method test strip (shown in color) that has tested samples of different standard concentrations in the measurement room, control the LED light source to emit light with the same intensity as that used in the previous step to irradiate the test strip, and then pass the color The sensor detects the scattered light, obtains the original color data corresponding to the dry chemical method test strips with different standard concentrations, takes the average value for three measurements, and multiplies the R, G, and B average values by the white balance conversion factor (obtained in step a), Obtain R, G, B white balance correction data of each concentration standard solution;

Step c: Convert the R, G, B white balance correction data (obtained in step b) after white balance correction to HSV (hue H, saturation S', lightness V) color space according to the formula, in this example, H is converted After that, H _max =346.87, in the S' conversion formula, S' _max =29.9, see Table 1 for the converted data.

Step d: First calculate the angle a between H and H _max of the current color, and then calculate the product of S' and coS(a) of the current color, which is the projection value of S' in the direction of the maximum concentration color H , to establish a linear equation of concentration and these projection values (as shown in Figure 5), which can be used to calculate the concentration of nitrite in an unknown sample.

Y＝0.2926X+205577

R ² =0.9797

Detecting result: Table 1 is the measuring result that adopts the present invention to measure nitrite standard solution. Fig. 5 is a data fitting diagram of the measurement results of nitrite in the present invention.

Table 1: HSV measurement results for nitrite standard solutions

From the results of the fitting graph, it can be seen that the method has a good linear relationship, and relatively accurate measurement results can be obtained in the range of 0 to 100 mg/Kg. However, only an approximate concentration range can be obtained by reading the test strips with human eyes.

The accurate detection of nitrite in embodiment 4 meat products

Take a sample of cured meat, and make the test paper develop color according to the method in the instruction manual of nitrite rapid detection test paper of Changchun Jida Little Swan Instrument Co., Ltd. Put the test paper in the measurement room, and select to start measurement in the control terminal.

Same as step a-step c of embodiment 3, the detection device converts the RGB signal of the detected sample to the HSV (hue H, saturation S', lightness V) color space after white balance correction. Use the method in step d of embodiment 3 to calculate the projection value of saturation S' in the direction of maximum concentration, and substitute this value into the linear equation obtained in step d of embodiment 3 to calculate the corresponding nitrite concentration in the sample. Finally, the control terminal shows that the nitrite content in the cured meat sample is 32.5mg/Kg.

The color test paper was compared with the nitrite standard color guide, and the result obtained was that the content in the cured meat sample was between 30 and 50 mg/Kg. This shows that the precise detection device based on the color sensor for dry chemical method can get the correct result and has better accuracy.

Claims (10)

1. the dry chemical method accurate detection device based on color sensor, including test strips measuring unit, LED light source component, face Colour sensor unit, communication unit and control unit, intensity continuously adjustabe white light LEDs are used as light in the LED light source component Source, with RGB (red, green, blueness) three color color sensors to test strip color, control in color sensor unit Using ARM microprocessor as core in unit, the detecting instrument accurately measured for dry chemical method test strips color is formed.

2. the dry chemical method accurate detection device based on color sensor as claimed in claim 1, it is characterised in that：Described Test strips measuring unit, including a lighttight measuring chamber, test strips to be measured are placed in measuring chamber, and LED light source is arranged on light The position of test strips to be measured is irradiated to, RGB color sensor is arranged on the position that can detect test strips color to be measured.

3. the dry chemical method accurate detection device based on color sensor as claimed in claim 2, it is characterised in that：The survey Amount interior sets hollow chamber and is used to place test strips, and two cylindrical channels are connected above measuring chamber, are used at the top of cylindrical channel In installation LED light source.

4. the dry chemical method accurate detection device based on color sensor as claimed in claim 3, it is characterised in that：The circle Shape passage length is 0.5CM-1CM, and at an angle with measuring chamber chamber plane, and its axis points to the center of test strips.

5. the dry chemical method accurate detection device based on color sensor as described in claim 3 or 4, it is characterised in that：Survey Square interface is set above amount room to be used to RGB color sensor be installed.

6. the dry chemical method accurate detection device based on color sensor as described in claim 3 or 4 or 5, it is characterised in that： The anterior oblong openings that are provided with of measuring chamber are used to test strips being put into, and the inside of oblong openings is provided with a movable lock lock, measurement Room cavity bottom is provided with guide rail and is used for the stable test strips being put into.

7. the dry chemical method accurate detection device based on color sensor as described in any one of claim 1 to 6, its feature exist In：

The LED light source component, including LED light source and the strong control circuit of LED light for being connected electrically control LED light source light intensity；

The color sensor unit, including RGB color sensor and the color sensor control circuit that is connected electrically；

Described control unit includes microprocessor, connection color sensor control circuit, color sensor control circuit and communication Unit, the sense command from control terminal is received by communication unit, exports LED light source by the strong control circuit of LED light The suitable optical signal of intensity, manipulation color sensor accept and believe color signal, and again via communication unit after white balance correction Pass to control terminal.

8. the dry chemical method accurate detection device based on color sensor as claimed in claim 7, it is characterised in that：It is described logical News unit is bluetooth module.

9. any one of the method that color and concentration relationship quantitative model are established based on color sensor, usage right requirement 1 to 8 institute Device is stated, is comprised the steps of：

Step a：Pure white test strips are placed in measuring chamber inner chamber, the light that control LED light source sends proper strength (senses color Device detected value is 80% or so of maximum output valve) it is irradiated in test strips, scattering light is then detected by color sensor, Original white balance color data is obtained, according to pure white RGB intensity red green blue identical principles, normalizing is carried out to initial data Change, calculate RGB three primary colors (red R, green G, blue B) respective white balance conversion factor；

Step b：The dry chemical method test strips (display color) for detecting various criterion concentration samples are placed in measuring chamber, controlled LED light source send with previous step used in intensity identical illumination be mapped in test strips, then by color sensor detect dissipate Light is penetrated, obtains the original color data corresponding to various criterion concentration samples dry chemical method test strips, by R, G, B initial data Respective white balance conversion factor is multiplied by, obtains R, G, B white balance correction data；

Step c：White balance correction data R, G, B after white balance correction is transformed into HSL by following formula (form and aspect H, to satisfy With degree S, brightness L) or HSV (form and aspect H, saturation degree S ', lightness V) color space：

If max is equivalent to the maximum in white balance correction data R, G, B, if min is equal to the reckling in these values, R, G, B The formula for turning H, S, L is as follows：

Form and aspect H has same definition and an algorithm in HSV and HSL, and saturation degree S ' and lightness V value are defined as follows in HSV：

ν=max

Step d：According to different colours situation of change, following any color and concentration of component relation causes are established：

If changed with change in concentration test paper color form and aspect, concentration and H relational model are established；

If changed with the saturation degree that change in concentration test paper is color, the relational model of concentration and S or S ' is established；

Or concentration and the relational model of polytomy variable in HSL or HSV.

10. based on color sensor to the assay method of concentration of component in sample, the face established using claim 9 methods described Color and concentration relationship quantitative model, are further implemented the steps of：

Step e：The dry chemical method test strips of unknown concentration sample are placed in measuring chamber inner chamber, control LED light source is sent and step a Intensity identical illumination is mapped in test strips (display color), is then detected scattering light by color sensor, is obtained unknown Original color data corresponding to concentration samples, unknown concentration sample R, G, B initial data is multiplied by white balance conversion factor, obtained To unknown concentration sample R, G, B white balance correction data；

Step f：R, G of the unknown concentration sample after step e white balance corrections, B data are turned with step c identicals method Change to HSL or HSV color spaces；

Step g：Data after step f is changed substitute into the causes that step d is determined, calculate in unknown concentration sample The concentration of the component.