A weak light signal data acquisition system for a laser confocal eyelid microscope

Abstract

A weak light signal data acquisition system for laser confocal eyelid microscope, comprising: photoelectric signal conversion amplification module, data acquisition module, host computer program module and signal modulation processing module. The photoelectric signal conversion amplification module uses a high-sensitivity photodetector to capture weak light signals with wavelengths of 200-900 nm and converts them into electrical signals, which are then amplified by a cross-group amplifier to ensure signal integrity and stability. The signal modulation circuit further improves the signal-to-noise ratio through an operational amplifier and RC filter network, and eliminates high-frequency system noise through a notch filter design. The data acquisition module acquires voltage signals, and the host computer program module realizes real-time control of the data acquisition process through graphical programming. The signal modulation processing module filters, fits, and arranges the digital signals to optimize the imaging quality. The system design effectively improves the clarity and accuracy of laser confocal microscope imaging, meeting the needs of high-precision imaging in ophthalmic medicine.

Description

TECHNICAL FIELD

[0001] The present application relates to a weak light signal data acquisition system for a laser confocal eyelid microscope. BACKGROUND

[0002] The laser confocal microscope is a high-precision instrument with extremely high resolution and strong layer cutting capability, and is one of the most widely used tools in the field of physiology and medicine. It uses the principle of conjugate imaging and precise pinhole spatial filtering technology to realize high signal-to-noise ratio imaging of the specified focal plane, and greatly filters the influence of stray light of the non-focal plane. However, this brings about the problem of weak reflected light signal intensity, which is generally 1-10nW. The traditional photoelectric signal acquisition system cannot meet the demand. And the laser confocal microscope contains electrical control, precision machinery, computer technology and other technologies, especially in the field of ophthalmology, the configuration, triggering mode and working mode of the signal acquisition system have higher and more flexible requirements, and there is no data acquisition system that can realize weak light signal data acquisition and be applied to eyelid examination scene.

[0003] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0004] The main purpose of the present application is to overcome the defects in the above background technology, and provide a weak light signal data acquisition system for a laser confocal eyelid microscope.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

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

[0007] A photoelectric signal conversion and amplification module is used to preamplify, filter and convert the weak light signal, so as to realize distortionless capture by the data acquisition module;

[0008] A data acquisition module is used to accurately complete the acquisition of the voltage signal under the triggering mechanism of the central control;

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

[0010] A signal modulation processing module is used to filter, fit and arrange the collected digital signal;

[0011] The photoelectric signal conversion and amplification module comprises:

[0012] A photoelectric detector is used to detect weak light signals with wavelengths of 200-900 nm and convert the light signals into electric signals.

[0013] A cross-group amplifier is connected to the electric signals output by the photoelectric detector, used to improve the response time and bandwidth of the signals and ensure the integrity and stability of the signals during transmission.

[0014] A signal modulation circuit is connected after the cross-group amplifier, realizing the second-stage amplification and filtering through an operational amplifier configuration, improving the signal-to-noise ratio of the analog signals, and further optimizing the signal quality by adding a notch filter to eliminate high-frequency system noise.

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

[0016] A V / A trans-impedance amplifier chip is used to convert the photoelectric current output by the photoelectric detector into a voltage signal.

[0017] A feedback resistor (Rf) and a feedback capacitor (Cf) are used to set the gain and bandwidth of the amplifier in cooperation with the V / A trans-impedance amplifier chip.

[0018] A gain amplifier is used to further amplify the signals.

[0019] A low-pass filter (LPF) is used to filter out noise outside the bandwidth and ensure the integrity of the signals.

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

[0021] Further, the signal modulation circuit comprises:

[0022] A first capacitor is connected between the input signal Uin and the non-inverting input terminal of the operational amplifier, 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, further filtering out high-frequency noise.

[0024] A second capacitor is connected in parallel with the first resistor, used to bypass high-frequency noise.

[0025] A third capacitor is connected between the second capacitor and the inverting input terminal of the operational amplifier, together with the second capacitor to form a double-capacitor filter network, enhancing the filtering effect.

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

[0027] An operational amplifier has its inverting input connected to the junction of the second resistor and the third capacitor, its non-inverting input connected to one end of the first capacitor and the output, and its output provides the amplified signal Uout.

[0028] The third resistor is connected to the connection line between the second and third capacitors;

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

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

[0031] Furthermore, the data acquisition module includes:

[0032] The data acquisition card can acquire voltage signals at a sampling rate of up to 80MHz and supports customizable triggering methods and sampling modes.

[0033] The control unit, using a field-programmable gate array (FPGA) chip, is responsible for communication and coordination between hardware components, including issuing enable signals, acquiring 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 parameters such as acquisition channels, sampling frequency, triggering mode, number of sampling points, and data storage method in real time.

[0036] The control unit can synchronize with the host computer program to coordinate the start and stop of the acquisition process with other components.

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

[0038] Digital filters are used to filter acquired digital signals to adapt to the pulse-like characteristics of the signals;

[0039] An integrator filter is used to integrate signals to reduce the impact of high-frequency noise.

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

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

[0042] The present application provides a weak light signal data acquisition system specially designed for a laser confocal eyelid microscope, which significantly improves the efficiency and quality of data acquisition through four coordinated modules according to the characteristics of high-precision instruments. First, the photoelectric signal conversion and amplification module adopts a high-linearity and high-sensitivity photoelectric detector, which is matched with a cross-group amplifier and a signal modulation circuit to realize efficient conversion and amplification of weak light signals with wavelengths of 200-900 nm, while effectively eliminating 50MHz system noise through the design of a wave trap to ensure the integrity and stability of the signal. Second, 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 signal acquisition system configuration, trigger mode and working mode. The upper computer program module adopts graphical programming, providing real-time, accurate and convenient control mode, making the data acquisition process more flexible and efficient. Finally, the signal modulation processing module processes the collected digital signals through digital filtering, integral filtering and adjustable Bessel digital filter, further optimizing the signal quality and improving the imaging clarity. Overall, the system of the present application 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 each module, meeting the needs of the physiological and medical fields for high-resolution imaging.

[0043] Other benefits of embodiments of the present application will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0044] Fig. 1 The structure block diagram of the weak light signal data acquisition system for the laser confocal eyelid microscope of the embodiments of the present application.

[0045] Fig. 2 The structure schematic diagram of the photoelectric signal conversion and amplification module of the embodiments of the present application.

[0046] Fig. 3 The circuit structure diagram of the cross-group amplifier of the embodiments of the present application.

[0047] Fig. 4 The circuit structure diagram of the signal modulation circuit of the embodiments of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present application and its applications.

[0049] It is to be understood that when an element such as a layer, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. It will also be understood that, when a device or element is referred to as being "coupled" to another device or element, mechanical or electrical connection between the devices or elements is not required.

[0050] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like, specify relative positions and orientations based on the orientations or positions shown in the drawings, and are used only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0051] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0052] Referring to Figs. 1-2 The embodiment of the present application 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 for pre-amplification, filtering and conversion of the weak light signal, so that the signal is captured by a data acquisition module without distortion; a data acquisition module, which is used for accurately completing the acquisition of the voltage signal under the triggering mechanism of central control; a host computer program module, which is used for completing the real-time control and configuration of the host computer on various parameters of the data acquisition module; and a signal modulation processing module, which is used for filtering, fitting and arranging the collected digital signal. The photoelectric signal conversion and amplification module comprises: a photoelectric detector, which is used for detecting the weak light signal with a wavelength of 200-900 nm and converting the light signal into an electric signal; a transconductance amplifier, which is connected with the electric signal output by the photoelectric detector and is used for improving the response time and bandwidth of the signal and ensuring the integrity and stability of the signal in the transmission process; and a signal modulation circuit, which is connected after the transconductance amplifier, realizes the second-stage amplification and filtering through the configuration of an operational amplifier, improves the signal-to-noise ratio of the analog signal, and eliminates the high-frequency system noise, especially the 50MHz specific frequency system noise, to further optimize the signal quality.

[0053] Referring to Fig. 3In a preferred embodiment, the cross-group amplifier comprises: a V / A transimpedance amplifier chip for converting the photoelectric current output by the photodetector into a voltage signal; a feedback resistor (Rf) and a feedback capacitor (Cf) cooperating with the V / A transimpedance amplifier chip for setting the gain and bandwidth of the amplifier; a gain amplifier for further amplifying the signal; and a low-pass filter (LPF) for filtering out noise outside the bandwidth to ensure the integrity of the signal. The circuit design of the cross-group amplifier can efficiently convert the photoelectric current output by the photodetector into a voltage signal while maintaining high gain and a wide bandwidth of 60MHz, and can well process the rapidly changing weak light signal. The combination of the gain amplifier and the low-pass filter (LPF) not only further amplifies the signal, but also effectively filters out noise outside the bandwidth, thereby improving the signal-to-noise ratio and stability of the signal. These characteristics together ensure the integrity of the signal during transmission and meet the needs of high-speed data acquisition.

[0054] Referring to Fig. 4 In a preferred embodiment, the signal modulation circuit comprises: a first capacitor C1 connected between the input signal Uin and the non-inverting input terminal of the operational amplifier, for coupling the input signal and filtering out the DC component; a first resistor R1 connected in series with the first capacitor C1 to form an RC filter network for further filtering 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, together with the second capacitor C2 to form a double-capacitor filter network to enhance the filtering effect; a second resistor R2 connected in parallel with the third capacitor C3 to form an RC filter network for further filtering out high-frequency noise; an operational amplifier with its inverting input terminal connected to the connection point of the second resistor R2 and the third capacitor C3, its non-inverting input terminal connected to one end of the first capacitor C1 and its output terminal, and its output terminal providing the amplified signal Uout; a third resistor R3 connected to the connection line of the second capacitor C2 and the third capacitor C3; and a fourth resistor R4 connected to the connection line of 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 filter network composed of the first capacitor C1 and the first resistor R1, in cooperation with the parallel configuration of the second capacitor C2, significantly improving the clarity of the signal. The double-capacitor filter network composed of the third capacitor C3 and the second capacitor C2, and the parallel configuration of the second resistor R2, further enhance the filtering effect, enabling the signal modulation circuit to more effectively process and optimize the signal, especially effectively eliminating 50MHz system noise. These designs provide a high-quality analog signal basis for subsequent digital signal processing, thereby improving the performance of the entire data acquisition system and enabling it to meet the high-precision imaging needs of the laser confocal eyelid microscope in the field of physiology and medicine.

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

[0056] In some embodiments, the data acquisition module comprises: a data acquisition card capable of collecting voltage signals at a sampling speed of up to 80 MHz, supporting self-programmed trigger mode and sampling mode; a control unit using a field programmable gate array (FPGA) chip, responsible for communication and coordination between hardware, including sending enable signals, collecting signals, and transferring synchronous position feedback signals.

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

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

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

[0060] Reference is made to Figs. 1-4 The present system is a solution for data acquisition and processing of a laser confocal eyelid high-precision microscope. The system consists of four modules. The photoelectric signal conversion and amplification module specifically pre-amplifies, filters and converts weak light signals, so that the weak light signals can be captured by the data acquisition card without distortion. The data acquisition module is used to accurately collect voltage signals under the trigger mechanism of central control. The host computer program module uses a graphical programming control to realize real-time control and configuration of the host computer on various parameters of the data acquisition card. The signal modulation processing module performs filtering, fitting and arrangement operations on the data. The entire system is designed for high-precision instruments such as laser confocal eyelid microscopes. Through the cooperative work of each module, the photoelectric signal data acquisition function of this specific instrument is realized, the transmission efficiency and quality of the data in this process are improved, and the performance of the entire instrument is improved.

[0061] Photoelectric signal conversion and amplification module

[0062] This module includes a photodetector, a transimpedance amplifier, and a modulation circuit. The working principle diagram is shown below.

[0063] The design adopts a photoelectric detector with high linearity, high sensitivity and small dark current, which can be used for weak light signal detection of 200-900 nm wavelength. Considering that the shot noise caused by dark current is very obvious in weak light intensity signal measurement, the design adopts a zero-bias working photovoltaic mode, which is applied to weak light signal detection with low frequency. The cross-group amplifier design carries 6040V / A chip, and the specific circuit design is shown in Fig. 3 The overall performance response time is 5.5 ns, and the bandwidth can reach 60 MHz, which is sufficient to meet the requirements.

[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, and to deal with the specific 50 MHz system noise. A notch filter is added for specific purpose, and the specific circuit design is shown in Fig. 4 .

[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 at a sampling speed of 80 MHz, and supports self-programming trigger mode and sampling mode. In order to meet the needs of laser confocal microscope 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 FPGA chip, which is mainly responsible for communication and coordination between multiple hardware, including the sending of enable signal, the sending of acquisition signal, and the transmission of synchronous position feedback signal, etc.

[0067] Host computer program module

[0068] The data acquisition process needs to be completed correctly under specified parameters and time. In order to realize real-time, accurate and convenient control of the host computer on the data acquisition process, a labview host computer program based on graphical programming is developed. Through this program, the host computer can easily and flexibly control the acquisition channel, sampling frequency, trigger mode, sampling point number, data saving mode, etc. in real time, and it is also convenient for the control unit to synchronize the process of starting and stopping the acquisition 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. The signal characteristics measured in the experiment are pulse type, 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 application provides a data acquisition system for an ophthalmic laser confocal eyelid microscope, which has a unique photoelectric conversion module design, can flexibly and efficiently control the whole acquisition process based on an image programming host computer program, realizes unique signal modulation, adapts to the characteristics of the acquired data, and performs targeted signal processing.

[0072] The above is a further detailed description of the application in combination with specific / preferred embodiments, and cannot be deemed as limiting the specific implementation of the application to these descriptions. For those skilled in the art to which the application belongs, without departing from the concept of the application, they can make several substitutions or modifications to the described embodiments, and these substitutions or modifications shall be deemed as falling within the protection scope of the application. In the description of the specification, the description of the terms "an embodiment", "some embodiments", "a preferred embodiment", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the application. In the specification, the illustrative description of the above terms does not necessarily refer to 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. Those skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction. Although the embodiments of the application 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 a laser confocal eyelid microscope, characterized in that, include: The photoelectric signal conversion and amplification module is used to pre-amplify, filter, and convert weak light signals so that they can be captured by the data acquisition module without distortion. The data acquisition module is used to accurately acquire voltage signals under the triggering mechanism of central control. The host computer program module is used to complete the real-time control and configuration of various parameters of the data acquisition module by the host computer; The signal modulation and processing module is used to perform operations such as filtering, fitting, and arranging on the acquired digital signals. The photoelectric signal conversion and amplification module includes: A photodetector is used to detect weak light signals with wavelengths of 200-900 nm and convert the light signals into electrical signals. A cross-group amplifier, connected to the electrical signal output by the photodetector, is used to improve the signal response time and bandwidth, and to ensure the integrity and stability of the signal during transmission. A signal modulation circuit, connected after the cross-group amplifier, implements second-stage amplification and filtering through operational amplifier configuration, improving the signal-to-noise ratio of the analog signal. It further optimizes signal quality by selectively adding a notch filter to eliminate high-frequency system noise. The signal modulation circuit eliminates 50MHz system noise through a notch filter design. The signal modulation circuit includes: a first capacitor connected between the input signal Uin and the non-inverting input of the operational amplifier, used to couple the input signal and filter out the DC component; a first resistor connected in series with the first capacitor to form an RC filter network, further filtering out high-frequency noise; a second capacitor connected in parallel with the first resistor to bypass high-frequency noise; a third capacitor connected between the second capacitor and the inverting input of the operational amplifier, forming a dual-capacitor filter network with the second capacitor to enhance the filtering effect; a second resistor connected in parallel with the third capacitor to form an RC filter network, further filtering out high-frequency noise; and an operational amplifier whose inverting input is connected to the junction of the second resistor and the third capacitor, and whose non-inverting input is connected to one end of the first capacitor and the output, providing the amplified signal Uout at the output.

2. The faint light signal data acquisition system for a laser confocal eyelid microscope of claim 1, wherein, The cross-group amplifier includes: 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), in conjunction with a V / A transimpedance amplifier chip, are used to set the amplifier's gain and bandwidth; Gain amplifiers are used to further amplify signals; A low-pass filter (LPF) is used to filter out noise outside the bandwidth to ensure signal integrity.

3. The faint light signal data acquisition system for a laser confocal eyelid microscope of any one of claims 1 to 2, wherein, The signal modulation circuit further includes: The 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 and third capacitors and grounded.

4. The faint light signal data acquisition system for a laser confocal eyelid microscope according to any one of claims 1 to 2, characterized in that, The photodetector operates in a photovoltaic mode with zero bias to detect weak light signals with wavelengths of 200–900 nm.

5. The faint light signal data acquisition system for a laser confocal eyelid microscope of any one of claims 1 to 2, wherein, The data acquisition module includes: The data acquisition card is capable of acquiring voltage signals at a sampling rate of up to 80MHz and supports customizable triggering methods and sampling modes. The control unit, using a field-programmable gate array (FPGA) chip, is responsible for communication and coordination between hardware components, including issuing enable signals, acquiring signals, and transmitting synchronous position feedback signals.

6. The faint light signal data acquisition system for a laser confocal eyelid microscope of claim 5, wherein, The host computer program module comprises: The host computer program based on graphical programming is used to realize real-time, accurate and convenient control of the data acquisition process; the program allows the host computer to control the parameters such as acquisition channel, sampling frequency, trigger mode, sampling point number, data saving mode in real time; The control unit can be synchronized with the host computer program to realize the coordination of the process of starting and stopping acquisition with other components.

7. The faint light signal data acquisition system for a laser confocal eyelid microscope of any one of claims 1 to 2, wherein, 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; An integral filter is used to integrate the signal to reduce the influence of high-frequency noise; An 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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