Weak light signal data acquisition system for laser confocal eyelid microscope

Abstract

A weak light signal data acquisition system for a laser confocal eyelid microscope comprises a photoelectric signal conversion amplification module, a data acquisition module, an upper computer program module and a signal modulation processing module. The photoelectric signal conversion and amplification module captures weak light signals with the wavelength of 200-900 nm through a high-sensitivity photoelectric detector, converts the weak light signals into electric signals and then amplifies the electric signals through a cross-group amplifier, so that the integrity and stability of the signals are ensured. The signal modulation circuit further improves the signal-to-noise ratio through an operational amplifier and an RC filter network, and eliminates the noise of a high-frequency system through the design of a wave trap. The data acquisition module acquires voltage signals, and the upper computer program module controls the data acquisition process in real time through graphical programming. And the signal modulation processing module filters, fits and arranges the digital signals, and optimizes the imaging quality. According to the system design, the definition and accuracy of laser confocal microscope imaging are effectively improved, and the requirement of ophthalmology medical high-precision imaging is met.

Description

Technical Field

[0001] The invention relates to a weak light signal data acquisition system for a laser confocal eyelid microscope. Background Art

[0002] The laser confocal microscope is a high-precision instrument with extremely high resolution and strong layer cutting ability. It is one of the most widely used tools in the field of physiology and medicine. It uses the principle of conjugate imaging and precision pinhole spatial filtering technology to achieve high signal-to-noise ratio imaging of the specified focal plane, and greatly filter out the influence of stray light in the non-focal plane. However, the resulting reflected light signal intensity is weak, generally 1 to 10nW, and the traditional photoelectric signal acquisition system cannot meet the demand. In addition, the laser confocal microscope contains a variety of technologies such as electrical control, precision machinery, and computer technology. Especially in the field of ophthalmic medicine, there are higher and more flexible requirements for the configuration, triggering method, and working mode of the signal acquisition system. However, there is currently no data acquisition system that can not only realize weak light signal data acquisition, but also be specifically applied to eyelid inspection scenarios.

[0003] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0004] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a weak light signal data acquisition system for laser confocal eyelid microscopy.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A weak light signal data acquisition system for laser confocal eyelid microscopy, comprising:

[0007] The photoelectric signal conversion and amplification module is used to pre-amplify, filter and convert weak optical signals so that they can be captured by the data acquisition module without distortion;

[0008] Data acquisition module, used to accurately complete the acquisition of voltage signals under the trigger mechanism of central control;

[0009] The host computer program module is used to complete the real-time control and configuration of the parameters of the data acquisition module by the host computer;

[0010] The signal modulation processing module is used to perform operations such as filtering, fitting and arranging the collected digital signals;

[0011] Wherein, the photoelectric signal conversion and amplification module includes:

[0012] Photoelectric detector, used to detect weak light signals with a wavelength of 200 to 900 nm and convert the light signals into electrical signals;

[0013] A cross-group amplifier connected to the electrical signal output by the photodetector, used to improve the response time and bandwidth of the signal and ensure the integrity and stability of the signal during transmission;

[0014] The signal modulation circuit is connected to the cross-group amplifier and realizes the second-stage amplification and filtering through the operational amplifier configuration to improve the analog signal-to-noise ratio, and further optimizes the signal quality by adding a notch filter to eliminate high-frequency system noise.

[0015] Further, the cross-group amplifier comprises:

[0016] V / A transimpedance amplifier chip, used to convert the photocurrent output by the photodetector into a voltage signal;

[0017] A feedback resistor (Rf) and a feedback capacitor (Cf) are used with the V / A transimpedance amplifier chip to set the gain and bandwidth of the amplifier;

[0018] A gain amplifier, used to further amplify the signal;

[0019] Low-pass filter (LPF) is used to filter out noise outside the bandwidth to ensure signal integrity.

[0020] Furthermore, the signal modulation circuit eliminates 50 MHz system noise through a notch filter design.

[0021] Furthermore, the signal modulation circuit comprises:

[0022] A first capacitor is connected between the input signal Uin and the in-phase input terminal of the operational amplifier, and is used to couple the input signal and filter out the DC component;

[0023] A first resistor is connected in series with the first capacitor to form an RC filter network to further filter out high-frequency noise;

[0024] A second capacitor, connected in parallel with the first resistor, for bypassing high frequency noise;

[0025] The third capacitor is connected between the second capacitor and the inverting input terminal of the operational amplifier, and together with the second capacitor forms a dual-capacitor filter network to enhance the filtering effect;

[0026] The second resistor is connected in parallel with the third capacitor to form an RC filter network to further filter out high-frequency noise;

[0027] An operational amplifier, whose inverting input terminal is connected to the connection point of the second resistor and the third capacitor, whose non-inverting input terminal is connected to one end of the first capacitor and the output terminal, and whose output terminal provides an amplified signal Uout;

[0028] A third resistor is connected to the connection line between the second capacitor and the third capacitor;

[0029] The fourth resistor is connected to the connection line between the second capacitor and the third capacitor and is grounded.

[0030] Furthermore, the photodetector operates in a photovoltaic mode of zero bias operation to detect weak light signals with a wavelength of 200 to 900 nm.

[0031] Furthermore, the data acquisition module includes:

[0032] Data acquisition card, capable of collecting voltage signals at a sampling rate of up to 80MHz, supporting self-programmable triggering and sampling modes;

[0033] The control unit, which uses a field programmable gate array (FPGA) chip, is responsible for communication and coordination between hardware, including sending enable signals, collecting signals, and transmitting synchronous position feedback signals.

[0034] Furthermore, the host computer program module includes:

[0035] The host computer program based on graphical programming is used to achieve real-time, accurate and convenient control of the data acquisition process; the program allows the host computer to control the acquisition channel, sampling frequency, trigger mode, number of sampling points, data storage method and other parameters in real time;

[0036] The control unit can be synchronized with the host computer program to achieve coordination of the acquisition start and stop process with other components.

[0037] Furthermore, the signal modulation processing module includes:

[0038] A digital filter is used to filter the collected digital signal to adapt to the pulse characteristics of the signal;

[0039] Integral filter, used to integrate the signal to reduce the impact of high-frequency noise;

[0040] Adjustable Bessel digital filter is used for low-pass filtering to further optimize signal quality and improve imaging clarity.

[0041] The present invention has the following beneficial effects:

[0042] The present invention provides a weak light signal data acquisition system designed for a laser confocal eyelid microscope. The system significantly improves the efficiency and quality of data acquisition through four collaborative modules based on the characteristics of high-precision instruments. First, the photoelectric signal conversion and amplification module adopts a high-linearity and high-sensitivity photodetector, cooperates with a cross-group amplifier and a signal modulation circuit, realizes the efficient conversion and amplification of weak light signals with a wavelength of 200 to 900 nm, and effectively eliminates the 50MHz system noise through the notch filter design, ensuring the integrity and stability of the signal. Secondly, the data acquisition module can accurately complete the acquisition of voltage signals under the trigger mechanism of central control, meeting the high requirements of the ophthalmic medical field for the configuration, triggering mode and working mode of the signal acquisition system. The host computer program module adopts graphical programming, providing a real-time, accurate and convenient control method, making the data acquisition process more flexible and efficient. Finally, the signal modulation processing module performs targeted processing on the collected digital signals through digital filtering, integral filtering and adjustable Bessel digital filter, further optimizing the signal quality and improving the imaging clarity. In general, the system of the present invention can not only capture weak light signals without distortion, but also significantly improve the performance of the laser confocal eyelid microscope through the coordinated work of various modules, meeting the demand for high-resolution imaging in the field of physiology and medicine.

[0043] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a structural block diagram of a weak light signal data acquisition system for a laser confocal eyelid microscope according to an embodiment of the present invention.

[0045] Figure 2 Schematic diagram of the structure of the photoelectric signal conversion and amplification module according to an embodiment of the present invention.

[0046] Figure 3 FIG. 4 is a circuit structure diagram of a cross-group amplifier according to an embodiment of the present invention.

[0047] Figure 4 FIG. 4 is a circuit structure diagram of a signal modulation circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0049] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0050] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0052] See also Figure 1 to Figure 2 The embodiment of the present invention provides a weak light signal data acquisition system for a laser confocal eyelid microscope, comprising: a photoelectric signal conversion and amplification module, which is used to pre-amplify, filter and convert the weak light signal so that it can be captured by the data acquisition module without distortion; a data acquisition module, which is used to accurately complete the acquisition of voltage signals under the trigger mechanism of central control; a host computer program module, which is used to complete the real-time control and configuration of various parameters of the data acquisition module by the host computer; a signal modulation processing module, which is used to filter, fit and arrange the collected digital signals; wherein the photoelectric signal conversion and amplification module comprises: a photodetector, which is used to detect weak light signals with a wavelength of 200 to 900 nm and convert the light signals into electrical signals; a cross-group amplifier, which is connected to the electrical signal output by the photodetector, and is used to improve the response time and bandwidth of the signal, and ensure the integrity and stability of the signal during transmission; a signal modulation circuit, which is connected to the cross-group amplifier, realizes the second-stage amplification and filtering through the operational amplifier configuration, improves the analog signal-to-noise ratio, and eliminates high-frequency system noise, especially 50MHz specific frequency system noise, by adding a notch filter in a targeted manner, so as to further optimize the signal quality.

[0053] See also Figure 3In a preferred embodiment, the cross-group amplifier includes: a V / A transimpedance amplifier chip, which is used to convert the photocurrent output by the photodetector into a voltage signal; a feedback resistor (Rf) and a feedback capacitor (Cf), which cooperate with the V / A transimpedance amplifier chip to set the gain and bandwidth of the amplifier; a gain amplifier, which is used to further amplify the signal; and a low-pass filter (LPF), which is used to filter out the noise outside the bandwidth to ensure the integrity of the signal. The circuit design of the cross-group amplifier can efficiently convert the photocurrent output by the photodetector into a voltage signal, while maintaining high gain and a wide bandwidth of 60MHz, and can handle rapidly changing weak light signals well. The combination of the gain amplifier and the low-pass filter (LPF) not only further amplifies the signal, but also effectively filters out the noise outside the bandwidth, thereby improving the signal-to-noise ratio and stability. These characteristics jointly ensure the integrity of the signal during transmission and meet the needs of high-speed data acquisition.

[0054] See also Figure 4 In a preferred embodiment, the signal modulation circuit includes: a first capacitor C1, connected between the input signal Uin and the in-phase input terminal of the operational amplifier, for coupling the input signal and filtering the DC component; a first resistor R1, connected in series with the first capacitor C1 to form an RC filter network to further filter out high-frequency noise; a second capacitor C2, connected in parallel with the first resistor R1, for bypassing high-frequency noise; a third capacitor C3, connected between the second capacitor C2 and the inverting input terminal of the operational amplifier, and together with the second capacitor C2, forming a dual-capacitor filter network to enhance the filtering effect; a second resistor R2, connected in parallel with the third capacitor C3, forming an RC filter network to further filter out high-frequency noise; an operational amplifier, whose inverting input terminal is connected to the connection point of the second resistor R2 and the third capacitor C3, and the in-phase input terminal is connected to one end of the first capacitor C1 and the output terminal, and the output terminal provides the amplified signal Uout; a third resistor R3, connected to the connection line between the second capacitor C2 and the third capacitor C3; a fourth resistor R4, connected to the connection line between the second capacitor C2 and the third capacitor C3 and grounded. The design of the signal modulation circuit forms an efficient high-frequency noise suppression system through the RC filtering network composed of the first capacitor C1 and the first resistor R1, and the parallel configuration of the second capacitor C2, which significantly improves the clarity of the signal. The dual-capacitor filtering network composed of the third capacitor C3 and the second capacitor C2, as well as the parallel configuration of the second resistor R2, further enhances the filtering effect, so that the signal modulation circuit can process and optimize the signal more effectively, especially effectively eliminate the 50MHz system noise. These designs provide a high-quality analog signal foundation for subsequent digital signal processing, thereby improving the performance of the entire data acquisition system, enabling it to meet the high-precision imaging requirements of laser confocal eyelid microscopy in the field of physiology and medicine.

[0055] In a preferred embodiment, the photodetector operates in a photovoltaic mode of zero bias operation to detect weak light signals with a wavelength of 200 to 900 nm.

[0056] In some embodiments, the data acquisition module includes: a data acquisition card, which can collect voltage signals at a sampling speed of up to 80 MHz and supports autonomously programmed triggering methods and sampling modes; a control unit, which uses a field programmable gate array (FPGA) chip and is responsible for communication and coordination between hardware, including issuing enable signals, collecting signals, and transmitting synchronous position feedback signals.

[0057] In some embodiments, the host computer program module includes: a host computer program based on graphical programming, which is used to achieve real-time, accurate and convenient control of the data acquisition process; the program allows the host computer to perform real-time control of parameters such as acquisition channel, sampling frequency, trigger mode, number of sampling points, data storage mode, etc. The control unit can be synchronized with the host computer program to achieve coordination of the acquisition start and stop process with other components.

[0058] In some embodiments, the signal modulation processing module includes: a digital filter for filtering the collected digital signal to adapt to the pulse characteristics of the signal; an integral filter for integrating the signal to reduce the impact of high-frequency noise; and an adjustable Bessel digital filter for low-pass filtering to further optimize the signal quality and improve imaging clarity.

[0059] The specific embodiments of the present invention are further described below.

[0060] See also Figures 1 to 4 This system is a solution for data acquisition and processing of laser confocal eyelid high-precision microscope. The system consists of 4 modules. The photoelectric signal conversion and amplification module pre-amplifies, filters and converts weak light signals specifically, so that weak light signals can be captured by the data acquisition card without distortion. The data acquisition module is used to accurately complete the acquisition of voltage signals under the trigger mechanism of central control. The host computer program module adopts a graphical programming control to complete the real-time control and configuration of various parameters of the data acquisition card by the host computer. The signal modulation processing module performs targeted operations such as filtering, fitting and arranging data. The entire system is aimed at high-precision instruments such as laser confocal eyelid microscopes. Through the collaborative work of various modules, the photoelectric signal data acquisition function of this specific instrument is completed, the data transmission efficiency and quality in this process are improved, and the performance of the entire instrument is improved.

[0061] Photoelectric signal conversion and amplification module

[0062] This module contains a photodetector, a cross-group amplifier, and a modulation circuit. The working principle diagram is shown below.

[0063] This design uses a photodetector with high linearity, high sensitivity and low dark current, which can be used to detect weak light signals with a wavelength of 200 to 900nm. Considering that the shot noise caused by dark current is very obvious in the measurement of weak light intensity signals, this design uses a photovoltaic mode with zero bias operation, which is applied to the detection of weak light signals with low frequency. The cross-group amplifier design is equipped with a 6040V / A chip. The specific circuit design is as follows Figure 3 As shown, the overall performance response time is within 5.5ns and the bandwidth can reach 60MHz, which is sufficient to meet the needs.

[0064] The modulation circuit can be regarded as the second stage of amplification and filtering, which is used to improve the signal-to-noise ratio of the analog signal. In order to deal with the specific 50MHz system noise, a notch filter design is added specifically. The specific circuit design is as follows Figure 4 shown.

[0065] Data acquisition module

[0066] The data acquisition module is mainly composed of a data acquisition card and a control unit. The data acquisition card can collect data at a sampling speed of 80MHz and supports self-programmed triggering and sampling modes. In order to meet the needs of laser confocal microscopy in eyelid examination, the data acquisition card needs to work synchronously with other components under the control of the control unit. The control unit uses an FPGA chip and is mainly responsible for communication and coordination between various hardware, including the issuance of enable signals, the issuance of acquisition signals, and the transmission of synchronous position feedback signals.

[0067] Host computer program module

[0068] The data acquisition process needs to be completed correctly at the specified parameters and time. In order to achieve real-time, accurate and convenient control of the data acquisition process by the host computer, a Labview host computer program based on graphical programming was developed. Through this program, the host computer can easily and flexibly control the acquisition channel, sampling frequency, trigger mode, number of sampling points, data storage method, etc. in real time, and it is also convenient for the control unit to synchronize the acquisition start and stop process with other components.

[0069] Signal modulation module

[0070] This module mainly completes the digital filtering function and performs targeted filtering on the digital signals collected by the previous modules. During the experiment, the measured signal characteristics are pulsed and accompanied by high-frequency noise, which seriously affects the final imaging quality. Therefore, this module first performs integral filtering on the signal, and then performs low-pass filtering through an adjustable Bessel digital filter.

[0071] The present invention proposes a data acquisition system for ophthalmic laser confocal eyelid microscopy, which has a unique photoelectric conversion module design and can flexibly and efficiently control the entire acquisition process based on the image programming host computer program. It realizes unique signal modulation, adapts to the characteristics of the collected data, and performs targeted signal processing.

[0072] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A weak light signal data acquisition system for laser confocal eyelid microscopy, characterized in that: include: The photoelectric signal conversion and amplification module is used to pre-amplify, filter and convert weak optical signals so that they can be captured by the data acquisition module without distortion; Data acquisition module, used to accurately complete the acquisition of voltage signals under the trigger mechanism of central control; The host computer program module is used to complete the real-time control and configuration of the parameters of the data acquisition module by the host computer; The signal modulation processing module is used to perform operations such as filtering, fitting and arranging the collected digital signals; Wherein, the photoelectric signal conversion and amplification module includes: Photoelectric detector, used to detect weak light signals with a wavelength of 200 to 900 nm and convert the light signals into electrical signals; A cross-group amplifier connected to the electrical signal output by the photodetector, used to improve the response time and bandwidth of the signal and ensure the integrity and stability of the signal during transmission; The signal modulation circuit is connected to the cross-group amplifier and realizes the second-stage amplification and filtering through the operational amplifier configuration to improve the analog signal-to-noise ratio, and further optimizes the signal quality by adding a notch filter to eliminate high-frequency system noise.

2. The weak light signal data acquisition system for laser confocal eyelid microscopy according to claim 1, characterized in that: The cross-group amplifier comprises: V / A transimpedance amplifier chip, used to convert the photocurrent output by the photodetector into a voltage signal; A feedback resistor (Rf) and a feedback capacitor (Cf) are used with the V / A transimpedance amplifier chip to set the gain and bandwidth of the amplifier; A gain amplifier, used to further amplify the signal; Low-pass filter (LPF) is used to filter out noise outside the bandwidth to ensure signal integrity.

3. The weak light signal data acquisition system for laser confocal eyelid microscopy according to claim 1 or 2, characterized in that: The signal modulation circuit eliminates 50MHz system noise through a notch filter design.

4. The weak light signal data acquisition system for laser confocal eyelid microscopy according to any one of claims 1 to 3, characterized in that: The signal modulation circuit comprises: A first capacitor is connected between the input signal Uin and the in-phase input terminal of the operational amplifier, and is used to couple the input signal and filter out the DC component; A first resistor is connected in series with the first capacitor to form an RC filter network to further filter out high-frequency noise; A second capacitor, connected in parallel with the first resistor, for bypassing high frequency noise; The third capacitor is connected between the second capacitor and the inverting input terminal of the operational amplifier, and together with the second capacitor forms a dual-capacitor filter network to enhance the filtering effect; The second resistor is connected in parallel with the third capacitor to form an RC filter network to further filter out high-frequency noise; An operational amplifier, whose inverting input terminal is connected to the connection point of the second resistor and the third capacitor, whose non-inverting input terminal is connected to one end of the first capacitor and the output terminal, and whose output terminal provides an amplified signal Uout; A third resistor is connected to the connection line between the second capacitor and the third capacitor; The fourth resistor is connected to the connection line between the second capacitor and the third capacitor and is grounded.

5. The weak light signal data acquisition system for laser confocal eyelid microscopy according to any one of claims 1 to 4, characterized in that: The photodetector operates in a photovoltaic mode of zero bias operation to detect weak light signals with a wavelength of 200 to 900 nm.

6. The weak light signal data acquisition system for laser confocal eyelid microscopy according to any one of claims 1 to 5, characterized in that: The data acquisition module comprises: Data acquisition card, capable of collecting voltage signals at a sampling rate of up to 80MHz, supporting self-programmable triggering and sampling modes; The control unit, which uses a field programmable gate array (FPGA) chip, is responsible for communication and coordination between hardware, including sending enable signals, collecting signals, and transmitting synchronous position feedback signals.

7. The weak light signal data acquisition system for laser confocal eyelid microscopy according to claim 6, characterized in that: The host computer program module includes: The host computer program based on graphical programming is used to achieve real-time, accurate and convenient control of the data acquisition process; the program allows the host computer to control the acquisition channel, sampling frequency, trigger mode, number of sampling points, data storage method and other parameters in real time; The control unit can be synchronized with the host computer program to achieve coordination of the acquisition start and stop process with other components.

8. The weak light signal data acquisition system for laser confocal eyelid microscopy according to any one of claims 1 to 7, characterized in that: The signal modulation processing module comprises: A digital filter is used to filter the collected digital signal to adapt to the pulse characteristics of the signal; Integral filter, used to integrate the signal to reduce the impact of high-frequency noise; The adjustable Bessel digital filter is used for low-pass filtering to further optimize the signal quality and improve the imaging clarity.

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