Multi-wavelength scanning imaging system

Abstract

The application provides a multi-wavelength scanning imaging system, and relates to the technical field of scanning imaging. The multi-wavelength scanning imaging system comprises: a light source module configured to output a target pulse sequence, the target pulse sequence comprising light pulses of multiple different wavelengths separated in the time domain; a scanning imaging module configured to receive the target pulse sequence, focus the target pulse sequence on a test sample by means of point-by-point scanning and scan; a photoelectric detection module configured to receive light signals generated by the test sample in response to the target pulse sequence and convert the light signals into electrical signals; and a time-domain splitting module configured to split the electrical signals according to pixel time. In each pixel time, the electrical signals are time-domain split based on the timing of the light pulses of the multiple different wavelengths in the target pulse sequence to obtain imaging signals of each pixel point, wherein the pixel time represents the time for which a scanning point stays at each pixel point in the process of point-by-point scanning by the scanning imaging module.

Description

Technical Field

[0001] This application relates to the field of scanning imaging technology, specifically to a multi-wavelength scanning imaging system. Background Technology

[0002] Point-scan imaging systems, through the coordinated operation of scanning and detection devices, sample point-by-point within a two-dimensional plane or three-dimensional volume of a sample and reconstruct image information. Point-scan imaging systems, including confocal microscopy, multiphoton imaging, and optical coherence tomography, are widely used in life sciences and materials science, enabling functions such as live-cell imaging, deep tissue observation, and accurate sample measurement and analysis. Furthermore, multi-wavelength illumination can provide more imaging information, expanding the application scenarios of point-scan imaging systems and making them a powerful tool for scientific research and disease diagnosis.

[0003] However, multi-wavelength imaging requires spectral detection of the imaging light signal, which on the one hand requires the introduction of complex optical devices and imaging detection devices; on the other hand, crosstalk between imaging light signals of different wavelengths greatly affects the accuracy of the imaging results. Summary of the Invention

[0004] In view of this, embodiments of this application provide a multi-wavelength scanning imaging system to simplify the structure of existing multi-wavelength point scanning imaging systems, while solving the problems of spectral crosstalk and reduced temporal resolution.

[0005] In a first aspect, one embodiment of this application provides a multi-wavelength scanning imaging system, comprising: a light source module configured to output a target pulse sequence, the target pulse sequence including multiple light pulses of different wavelengths separated in the time domain; a scanning imaging module configured to receive the target pulse sequence, focus the target pulse sequence onto a test sample and scan it using a point-by-point scanning method; a photoelectric detection module configured to receive an optical signal generated by the test sample in response to the target pulse sequence, and convert the optical signal into an electrical signal; and a time-domain splitting module configured to split the electrical signal according to pixel time; within each pixel time, based on the timing of the multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is split in the time domain to obtain an imaging signal for each pixel, wherein the pixel time represents the time during which the scanning imaging module stays on each pixel during the point-by-point scanning process.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the time response bandwidth of the photoelectric detection module is greater than the ratio of the number of light pulses contained in the target pulse sequence to the pixel time.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the light source module includes: at least one light source configured to output multiple illumination lights of different wavelengths, the illumination lights including continuous illumination lights or pulsed illumination lights; an optical power modulator configured to perform time-on-off modulation on the multiple illumination lights of different wavelengths to generate a target pulse sequence; the time response bandwidth of the optical power modulator is greater than the ratio of pixel time to the number of wavelengths of illumination light.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the light source module includes: a multi-wavelength synchronous pulse laser configured to output multiple light pulses of different wavelengths; and a timing adjustment unit configured to adjust the relative time delay between the multiple light pulses of different wavelengths to generate a target pulse sequence; wherein the light pulses of each wavelength output by the multi-wavelength synchronous pulse laser have the same repetition frequency and constant phase delay, and the repetition frequency is greater than the pixel frequency, so that each pixel time contains at least one set of target pulse sequences.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the timing adjustment unit achieves the relative time delay of multiple optical pulses of different wavelengths by adjusting the optical path difference of multiple optical pulses of different wavelengths.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the timing adjustment unit achieves the relative time delay of multiple optical pulses of different wavelengths by adjusting the fiber lengths corresponding to each of the multiple optical pulses of different wavelengths.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the photoelectric detection module includes: at least one photodetector configured to convert an optical signal into an initial electrical signal; and an amplifier configured to amplify the initial electrical signal to obtain an electrical signal.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the scanning imaging module includes a uniform point-by-point scanning method and a non-uniform point-by-point scanning method; preferably, the point-by-point scanning method includes one of a grid scanning method, a Lissajous scanning method, a spiral scanning method, and a hexagonal scanning method.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the scanning imaging module includes at least one of a laser scanning confocal microscope, a multiphoton imaging system, and an optical coherence tomography system; preferably, the target pulse sequence enters the scanning imaging module through a free-space optical path or an optical fiber.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the temporal domain splitting module realizes the splitting of pixels and the reconstruction of multi-wavelength images based on the scanning synchronization signal and the wavelength synchronization signal.

[0015] The multi-wavelength scanning imaging system provided in this application provides a target pulse sequence output by a light source module. The scanning imaging module focuses the received target pulse sequence onto the test sample using a point-by-point scanning method. Then, a photoelectric detection module receives the light signal generated by the test sample in response to the target pulse sequence and converts the light signal into an electrical signal. Since the target pulse sequence includes multiple light pulses of different wavelengths separated in time, these pulses do not overlap in the temporal domain. Therefore, this application can acquire the light signals corresponding to all wavelengths of light pulses without using multiple photoelectric detection modules. The electrical signal is split into pixel-time segments by a time-domain segmentation module: within each pixel time, based on the temporal sequence of multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is time-domain segmented to obtain the imaging signal for each pixel, thereby obtaining the imaging signal of different wavelengths of light pulses at each pixel, completing the imaging of the test sample. In this embodiment, the absence of multiple photoelectric detection modules enhances the structural flexibility of the multi-wavelength scanning imaging system. Furthermore, the use of temporal separation avoids spectral crosstalk, improving the accuracy of the test sample imaging results. In addition, the splitting of pixel time increases the pixel rate of the scanning imaging system, thus maintaining the same temporal resolution as single-wavelength imaging, which is beneficial for achieving rapid multi-wavelength imaging. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 The diagram shown is a schematic diagram of the structure of a multi-wavelength scanning imaging system provided in an exemplary embodiment of this application.

[0018] Figure 2 The diagram shown is a schematic diagram of a raster scanning method provided in an exemplary embodiment of this application.

[0019] Figure 3 The diagram shown is a schematic diagram of time-domain splitting of an electrical signal provided by an exemplary embodiment of this application.

[0020] Figure 4 The diagram shown is a schematic diagram of a point scanning imaging method provided in an exemplary embodiment of this application.

[0021] Figure 5 The diagram shown is a schematic diagram of a point scan imaging method provided in another exemplary embodiment of this application.

[0022] Figure 6 The diagram shown is a schematic diagram of the target pulse sequence output provided in an exemplary embodiment of this application.

[0023] Figure 7 The diagram shown is a schematic representation of the target pulse sequence output provided in another exemplary embodiment of this application.

[0024] Figure 8 The diagram shown is a schematic representation of the target pulse sequence output provided in another exemplary embodiment of this application.

[0025] Figure 9 The diagram shown is a system schematic of a multi-wavelength scanning imaging system provided in an exemplary embodiment of this application.

[0026] Figure 10 The diagram shown is a schematic diagram of the structure of a photoelectric detection module provided in an exemplary embodiment of this application.

[0027] Figure 11 The diagram shown is a flowchart of a multi-wavelength scanning imaging method provided in an exemplary embodiment of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Point scanning imaging is based on a rapid point-by-point scanning of the test sample using an optical scanning device, acquiring sample information only at the focal point at each time point. Furthermore, the imaging signal is recorded point by point using a point imaging detector, and finally, high-resolution, high-contrast imaging of the test sample is achieved based on the cascaded imaging signals.

[0030] Currently, point scanning imaging systems typically use multiple light sources of different wavelengths to obtain more imaging information. However, providing multiple light sources of different wavelengths simultaneously requires multiple different single-point photodetectors for signal acquisition. On the one hand, this results in poor structural flexibility of the imaging system; on the other hand, it also introduces the problem of spectral crosstalk, affecting the accuracy of the measurement results.

[0031] To address the aforementioned technical problems, this application provides a multi-wavelength scanning imaging system to improve the structural flexibility and accuracy of the imaging results.

[0032] Figure 1 The diagram shown is a schematic representation of a multi-wavelength scanning imaging system provided in an exemplary embodiment of this application. Figure 1 As shown, the multi-wavelength scanning imaging system provided in this application embodiment includes: a light source module 110 configured to output a target pulse sequence; a scanning imaging module 120 configured to receive the target pulse sequence, focus the target pulse sequence on the test sample and scan it using a point-by-point scanning method; a photoelectric detection module 130 configured to receive the light signal generated by the test sample in response to the target pulse sequence and convert the light signal into an electrical signal; and a time-domain splitting module 140 configured to split the electrical signal according to pixel time; within each pixel time, based on the timing of multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is split in the time domain to obtain the imaging signal of each pixel.

[0033] Optionally, the target pulse sequence includes multiple optical pulses of different wavelengths separated in the time domain. It can be seen that in the target pulse sequence, the output times of optical pulses of different wavelengths do not overlap, and there is no inter-wavelength interference. For example, the target pulse sequence contains optical pulses of three different wavelengths: wavelength 1, wavelength 2, and wavelength 3. These three different wavelengths are output sequentially in time without interfering with each other.

[0034] In an exemplary embodiment of this application, the light source module 110 continuously outputs multiple target pulse sequences and transmits these sequences to the scanning imaging module 120. The timing of the transmission of light pulses of different wavelengths is synchronized with the time-domain splitting module 140, i.e., a timing synchronization signal is sent to the time-domain splitting module 140. The scanning imaging module 120 controls the light pulses in the target pulse sequences to generate beam deflection, focusing the target pulse sequences onto the test sample. By controlling the angle of beam deflection, the position of the focal point on the test sample continuously changes, thereby performing two-dimensional or three-dimensional scanning of the test sample.

[0035] The light spot formed by focusing the target pulse sequence on the test sample can be called a scanning point. During the scanning imaging process, the scanning point moves on the test sample according to a preset scanning path, and a pixel is formed in the photoelectric detection module 130 at each position. When the target pulse sequence is focused on the test sample, it generates light signals through various physical and chemical mechanisms. These signals carry information such as the morphology, structure, and chemical composition of the test sample, which is the core basis for optical imaging.

[0036] In some embodiments, the scanning imaging module 120 includes a uniform point-by-point scanning mode and a non-uniform point-by-point scanning mode; preferably, the point-by-point scanning mode includes one of a grid scanning mode, a Lissajous scanning mode, a spiral scanning mode, and a hexagonal scanning mode.

[0037] In uniform point-to-point scanning, the scanning points move across the test sample at a constant speed, with each pixel remaining for the same amount of time, thus ensuring image uniformity. In non-uniform point-to-point scanning, however, the scanning point speed can be adjusted according to actual needs. For example, in areas requiring high-resolution display, the moving speed is slowed down to obtain sufficient light signal; in areas where resolution requirements are not high, the moving speed can be increased to improve imaging efficiency.

[0038] Figure 2 The diagram illustrates a grid scanning method provided in an exemplary embodiment of this application. Optionally, the scanning path of the grid scanning method is a horizontal line-by-line scan. Figure 2 As shown, a scanning method with equal angle increments is used to perform horizontal line-by-line scanning of the test sample, thereby forming multiple pixels in the photoelectric detection module 130.

[0039] For example, during the line-by-line scanning process, each line contains 8 pixels: pixel 1, pixel 2, ..., pixel 8, and each pixel has the same pixel time. Assuming each pixel corresponds to N sets of target pulse sequences (N is an integer greater than or equal to 1), light signals corresponding to each wavelength are generated synchronously with the target pulse sequences. Furthermore, during the scanning process, the scanning imaging module 120 sends the timing synchronization signal of the generated light pulses to the time-domain splitting module 140.

[0040] In order to acquire optical signals, in an exemplary embodiment of this application, at least one photodetector module 130 may be deployed based on the transmission path of the optical signal generated by the test sample. The photodetector module 130 utilizes the photoelectric effect to convert the optical signal into an electrical signal.

[0041] For example, the photoelectric detection module 130 continuously receives optical signals, performs high-speed analog-to-digital sampling on the optical signals, and then obtains electrical signals. The electrical signals contain signal segments corresponding to multiple pixels. In order to determine the imaging information of each pixel, this application uses a time-domain splitting module 140 to split the continuously received electrical signals according to pixel time. Here, pixel time represents the time that the scanning point stays on each pixel during the point-by-point scanning process of the scanning imaging module.

[0042] In some embodiments, the pixel time and scanning order of each pixel during the scanning process of the test sample can be recorded. The time-domain splitting module 140 splits the electrical signal according to the pixel time to obtain the split electrical signal. Furthermore, based on the scanning order, the correspondence between each electrical signal and the pixel can be determined.

[0043] Furthermore, during the scanning process, the number of target pulse sequences illuminating each pixel can be recorded; for example, this number is greater than or equal to 1. For the segmented electrical signal corresponding to each pixel, the segmented electrical signal is further segmented according to the number of target pulse sequences and the timing of multiple light pulses of different wavelengths within the target pulse sequences. The newly segmented electrical signal is analyzed and processed to obtain the imaging signal corresponding to that pixel for different wavelengths. The imaging signal reflects the imaging parameters of the test sample at that pixel, such as color parameters.

[0044] Figure 3 The diagram shown is a schematic representation of time-domain splitting of an electrical signal according to an exemplary embodiment of this application. Figure 3 As shown, each target pulse sequence consists of light pulses corresponding to three different wavelengths: wavelength 1, wavelength 2, and wavelength 3. Each pixel corresponds to six target pulse sequences, and the pixel times of different pixels are the same. Correspondingly, each target pulse sequence corresponds to a set of optical signals. After converting the optical signals into electrical signals, and then performing time-domain decomposition on the electrical signals, the imaging signals corresponding to different wavelengths for each pixel can be obtained. (Refer to...) Figure 3 As shown, a pixel within the first pixel time period is divided into 6 imaging signals corresponding to wavelength 1, 6 imaging signals corresponding to wavelength 2, and 6 imaging signals corresponding to wavelength 3.

[0045] The multi-wavelength scanning imaging system provided in this application provides a target pulse sequence output by a light source module. The scanning imaging module focuses the received target pulse sequence onto the test sample using a point-by-point scanning method. Then, a photoelectric detection module receives the light signal generated by the test sample in response to the target pulse sequence and converts the light signal into an electrical signal. Since the target pulse sequence includes multiple light pulses of different wavelengths separated in time, these pulses do not overlap in the temporal domain. Therefore, this application can acquire the light signals corresponding to all wavelengths of light pulses without using multiple photoelectric detection modules. The electrical signal is split into pixel-time segments by a time-domain segmentation module: within each pixel time, based on the temporal sequence of multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is time-domain segmented to obtain the imaging signal for each pixel, thereby obtaining the imaging signal of different wavelengths of light pulses at each pixel, completing the imaging of the test sample. In this embodiment, the absence of multiple photoelectric detection modules enhances the structural flexibility of the multi-wavelength scanning imaging system. Furthermore, the use of temporal separation avoids spectral crosstalk, improving the accuracy of the test sample imaging results. In addition, the splitting of pixel time increases the pixel rate of the scanning imaging system, thus maintaining the same temporal resolution as single-wavelength imaging, which is beneficial for achieving rapid multi-wavelength imaging.

[0046] The following is combined Figure 4 and Figure 5 The point scanning imaging method will be explained.

[0047] Figure 4 The diagram shown is a schematic representation of a point scan imaging method provided in an exemplary embodiment of this application. Figure 4 As shown, the point scanning process is illustrated using a single-axis scanning galvanometer as an example of line scanning. The scanning imaging module 120 includes a scanning device 121 and an imaging lens 122. The target pulse sequence output by the light source module is transmitted through a series of optical elements and finally incident on the scanning device 121. After receiving the target pulse sequence, the scanning device 121 adjusts its swing angle and speed according to a preset scanning mode, thereby deflecting the light beam of the target pulse sequence and focusing the light pulses in the target pulse sequence onto a designated position on the test sample, forming a scanning point. In addition, as the scanning device 121 continues to swing, the scanning point moves on the test sample according to a preset scanning direction, thereby realizing two-dimensional or three-dimensional scanning of the test sample.

[0048] Furthermore, the system principle of the multi-wavelength scanning imaging system can be explained in conjunction with the scanning imaging module 120 provided in the embodiments of this application.

[0049] Figure 5 The diagram shown is a schematic representation of a point scan imaging method provided in another exemplary embodiment of this application. Figure 5 The diagram illustrates the illumination excitation and imaging process using multiphoton imaging as an example. The scanning imaging module 120 includes a scanning device 121, an imaging lens 122, and a dichroic mirror 123. The imaging lens 122 is located above the test sample and is used to collect the light signal generated by the test sample in response to the target pulse sequence.

[0050] In this embodiment, after receiving the target pulse sequence, the scanning device 121 changes the propagation direction of the light pulses in the target pulse sequence, causing them to propagate to the dichroic mirror 123. By reasonably setting the reflection and transmission wavelength range of the dichroic mirror 123, light pulses of different wavelengths in the target pulse sequence can be separated and finally focused onto the test sample by the imaging lens 122 to excite the test sample to generate a light signal. After being collected by the imaging lens 122, the light signal returns along the original optical path, passes through the dichroic mirror 123 again, and is then received by the photoelectric detection module 130.

[0051] To ensure that the photodetector module can distinguish multiple densely arranged target pulse sequences within the same pixel time interval, the response speed of the photodetector module needs to be fast enough. In some embodiments, the time response bandwidth of the photodetector module is greater than the ratio of the number of light pulses contained in the target pulse sequence to the pixel time interval.

[0052] Time response bandwidth is an indicator that measures the frequency range that a photodetector module can detect, reflecting its ability to respond to fast optical signals. The ratio of the number of light pulses in a target pulse sequence to the pixel time reflects the number of light pulses contained in a single pixel. A larger ratio indicates a denser density of light pulses within the pixel time, requiring a faster response speed from the photodetector module.

[0053] When the time response bandwidth of the photoelectric detection module is greater than this ratio, it can be guaranteed that the photoelectric detection module can accurately receive and respond to the light signals generated by light pulses of all different wavelengths within each pixel time, and then convert them into electrical signals. This ensures that the imaging information of each pixel can be completely and accurately collected, thereby improving the quality and accuracy of imaging.

[0054] In an exemplary embodiment of this application, the light source module 110 includes: at least one light source configured to output multiple illumination lights of different wavelengths, the illumination lights including continuous illumination lights or pulsed illumination lights; and an optical power modulator configured to perform time-on-off modulation on the multiple illumination lights of different wavelengths to generate a target pulse sequence. The time response bandwidth of the optical power modulator is greater than the ratio of pixel time to the number of wavelengths of the illumination light.

[0055] In some embodiments, the light source includes a continuous laser, a pulsed laser, and a light-emitting diode, etc. The optical power modulator includes an electro-optic crystal modulator and an acousto-optic crystal modulator, etc.

[0056] Specifically, pulsed lasers concentrate energy into a very short time (nanosecond to femtosecond range) for emission through a periodic energy storage and release mechanism, forming pulsed illumination light with high peak power. Light-emitting diodes (LEDs) are semiconductor devices that convert optical signals into electrical signals. Continuous lasers are devices capable of continuously outputting a stable laser beam.

[0057] On-off modulation refers to controlling an optical power modulator to make the illumination light output by the light source switch on and off in time, thereby generating a target pulse sequence. For example, the optical power modulator can modulate the illumination light output by the light source according to a preset modulation signal, so that the illumination light allows or blocks the light signal to pass through at specific time points, thereby forming a series of separate light pulses in time, i.e., the target pulse sequence.

[0058] It should be noted that the ratio of pixel time to the number of wavelengths of illumination light reflects the illumination time that each wavelength of illumination light can be allocated during the illumination of a scan point. By ensuring that the time response bandwidth of the optical power modulator is greater than this ratio, the emission wavelength of the optical power modulator is fast enough to accurately modulate the on / off state of multiple different wavelengths of illumination light within the pixel time, ensuring that each wavelength of illumination light can illuminate the scan point and generate the corresponding optical signal.

[0059] By employing on-off modulation, the timing of the light pulses output by the light source can be flexibly controlled, thereby meeting the requirements of multi-wavelength scanning imaging systems. Furthermore, the optical power modulator can simultaneously change the optical power of different wavelengths when outputting light pulses of different wavelengths, thus optimizing the transmission of optical signals.

[0060] In an exemplary embodiment of this application, each light source corresponds to one optical power modulator. The light source module 110 also includes a beam combiner, which is disposed downstream of each optical power modulator to couple light pulses of different wavelengths modulated by the optical power modulator into a single beam, enabling multiple light pulses of different wavelengths to be transmitted along the same optical path to the scanning imaging module. Exemplarily, the beam combiner includes optical elements such as a dichroic mirror, a polarizing beam combiner, and a reflector. The dichroic mirror transmits almost completely light of a certain wavelength while reflecting almost completely light of other wavelengths. The reflector changes the direction of the light path, focuses light, or diverges light through reflection.

[0061] Figure 6 The diagram shown is a schematic representation of the target pulse sequence output provided in an exemplary embodiment of this application; as shown Figure 6 As shown, the light source module 110 includes at least one light source 111 and an optical power modulator 112. The wavelengths of the light pulses output by the three light sources 111 are wavelength 1, wavelength 2, and wavelength 3, respectively, where wavelength 1 is shorter than wavelength 2, and wavelength 2 is shorter than wavelength 3. Each light source 111 corresponds to one optical power modulator 112, and the light pulses output by the optical power modulator 112 are coupled through a beam combiner. The optical power modulator 112 is a device that controls the beam power through an external signal.

[0062] For example, the beam combining element includes a mirror and a dichroic mirror. (e.g.) Figure 6 As shown, the light pulse corresponding to wavelength 1 is adjusted by the reflector 113 to adjust the light path direction, the light pulse of wavelength 2 is adjusted by the first dichroic mirror 114 to adjust the beam direction, and is combined by the second dichroic mirror 115 to finally obtain a target pulse sequence with the beam direction consistent for multiple wavelengths.

[0063] The light source module provided in this application embodiment can ensure that light pulses of different wavelengths do not overlap in the time domain. By combining the light pulses generated by multiple light sources, the complex beam splitting optical path design of traditional multi-wavelength imaging systems can be avoided. Furthermore, there is no need to set up multiple detectors corresponding to different imaging wavelengths. Multi-wavelength imaging of a single detector imaging system can be achieved through time division multiplexing, which simplifies the optical path design of multi-wavelength scanning imaging systems and effectively generates a target pulse sequence containing light pulses of multiple wavelengths.

[0064] In some embodiments, a target pulse sequence can also be obtained by time-delaying the light pulses of different wavelengths output by a phase-locked multi-wavelength light source. Specifically, the light source module 110 includes: a multi-wavelength synchronous pulse laser configured to output multiple light pulses of different wavelengths; and a timing adjustment unit configured to adjust the relative time delay between the multiple light pulses of different wavelengths to generate a target pulse sequence; wherein the light pulses of each wavelength output by the multi-wavelength synchronous pulse laser have the same repetition frequency and constant phase delay, and the repetition frequency is greater than the pixel frequency, so that each pixel time contains at least one set of target pulse sequences.

[0065] Multi-wavelength synchronous pulsed lasers include solid-state lasers, gas lasers, and semiconductor lasers. Timing adjustment units include optical elements such as optical delay lines and optical switches. Relative time delay refers to the time difference between optical pulses of different wavelengths. By adjusting this time difference, it can be ensured that optical pulses of different wavelengths are output sequentially in time, thus forming a series of separate optical pulses, i.e., the target pulse sequence.

[0066] It should be noted that repetition frequency refers to the number of light pulses output per unit time for different wavelengths; pixel frequency refers to the number of light pulses contained in each pixel. By setting the repetition frequency to be greater than the pixel frequency, the multi-wavelength synchronous pulsed laser can output a sufficient number of light pulses per unit time, ensuring that each pixel contains at least one set of target pulse sequences, thus guaranteeing the integrity and accuracy of the imaging. By maintaining a constant phase delay, the relative positions of the light pulses of different wavelengths output by the multi-wavelength synchronous pulsed laser can be ensured in time, guaranteeing the accurate temporal separation of the light pulses of different wavelengths in the target pulse sequence.

[0067] The embodiments of this application employ phase-locked loop (PLL) technology combined with timing adjustment, which can precisely control the timing of light pulses of different wavelengths and effectively generate a target pulse sequence containing light pulses of multiple wavelengths.

[0068] In an exemplary embodiment of this application, the timing adjustment unit achieves the relative time delay of multiple light pulses of different wavelengths by adjusting the optical path difference of multiple light pulses of different wavelengths.

[0069] To more clearly explain how relative time delays occur, the following is provided: Figure 7 . Specifically, Figure 7 The diagram shown is a schematic representation of the target pulse sequence output provided in another exemplary embodiment of this application. Figure 7As shown, the multi-wavelength synchronous pulse laser 116 outputs optical pulses with wavelengths of wavelength 1, wavelength 2, and wavelength 3. Further, the timing adjustment unit 117 sets different optical paths for the optical pulses of different wavelengths. There is an optical path difference between the different optical paths, which causes a relative time delay in the timing of the optical pulses of different wavelengths. For example, the optical paths corresponding to wavelengths 1, 2, and 3 become progressively longer. Accordingly, the optical pulse of wavelength 1 arrives before the optical pulse of wavelength 2, and the optical pulse of wavelength 2 arrives before the optical pulse of wavelength 3, resulting in a relative time delay. Further, the optical path of the optical pulse corresponding to wavelength 1 is adjusted by the reflector 113, and the optical path of the optical pulse corresponding to wavelength 2 is adjusted by the second dichroic mirror 115. The optical pulses are then combined by the second dichroic mirror 115. Based on the relative time delay of the optical pulses of different wavelengths, a target pulse sequence is generated.

[0070] This application embodiment sets different optical paths for light pulses of different wavelengths, thereby creating an optical path difference between the light pulses of different wavelengths, and thus achieving a relative time delay in the timing of the light pulses. This method does not require complex electronic control; the timing of the light pulses can be adjusted using only optical components, and has the advantages of simple structure and high stability.

[0071] In an exemplary embodiment of this application, the timing adjustment unit achieves the relative time delay of multiple optical pulses of different wavelengths by adjusting the optical fiber lengths corresponding to each of the multiple optical pulses of different wavelengths.

[0072] Specifically, different fiber lengths can be used for optical pulses of different wavelengths in the timing adjustment unit. Since light takes time to propagate through the fiber, different fiber lengths will cause differences in the arrival time of the optical pulses to subsequent processing modules. For example, a shorter fiber can be used for wavelength 1, a medium-length fiber for wavelength 2, and a longer fiber for wavelength 3. The wavelength 1 pulse arrives first after passing through the short fiber, the wavelength 2 pulse arrives second after passing through the medium-length fiber, and the wavelength 3 pulse arrives last after passing through the long fiber, thus achieving a relative time delay for optical pulses of different wavelengths.

[0073] Figure 8 The diagram shown is a schematic representation of the target pulse sequence output provided in another exemplary embodiment of this application. Figure 8 As shown, a multi-wavelength synchronous pulsed laser 116 outputs optical pulses with wavelengths of wavelength 1, wavelength 2, and wavelength 3. Each optical pulse of a different wavelength passes through an optical fiber coupler 118, which couples the optical pulses of different wavelengths to independent optical fibers 119. It should be noted that multiple optical pulses of different wavelengths correspond to different optical fiber lengths, resulting in a relative time delay in the timing of the optical pulses of different wavelengths, thereby generating the target optical pulse sequence.

[0074] By appropriately designing the length of optical fibers, the time difference between optical pulses of different wavelengths can be precisely controlled. This method of achieving relative time delay using differences in fiber length is simple to operate, low in cost, and ensures the stability of optical pulses during transmission, which is beneficial for improving the performance and imaging quality of multi-wavelength scanning imaging systems.

[0075] In an exemplary embodiment of this application, the scanning imaging module 120 includes at least one of a laser scanning confocal microscope, a multiphoton imaging system, and an optical coherence tomography system; the target pulse sequence enters the scanning imaging module 120 through a free space optical path or an optical fiber.

[0076] Laser scanning confocal microscopy is a modern biomedical imaging instrument; it adds a laser scanning device to fluorescence microscopy imaging, using ultraviolet or visible light to excite fluorescent probes. Multiphoton imaging systems utilize the nonlinear optical effects generated by photons within a sample to achieve high-resolution three-dimensional imaging. Optical coherence tomography (OCT) systems are non-contact microscopic imaging devices based on the principle of low-coherence optical interference, constructing two-dimensional or three-dimensional structural images of biological tissues by measuring backscattered light delay information. Free-space optical path refers to the optical path of light propagating in free space.

[0077] Optionally, the number of optical fibers can be determined based on the number of wavelengths of the optical pulses in the target pulse sequence. The scanning imaging module includes a high-speed scanning device, which may include a polygonal rotating scanning mirror, a wobbling scanning galvanometer, or a MEMS (Micro-Electro-Mechanical System) micromirror. Since the scanning frequency of the scanning device is typically several hundred to several thousand hertz, the pixel rate of a multi-wavelength scanning imaging system is typically less than 10 MHz.

[0078] Figure 9 The diagram shown is a system schematic of a multi-wavelength scanning imaging system provided in an exemplary embodiment of this application. Figure 9 As shown, after receiving the target pulse sequence, the scanning device 121 adjusts its angle to deflect the beam of the target pulse sequence, so that the target pulse sequence is focused onto the test sample through the imaging lens 122. As the scanning device 121 continues to oscillate, the scanning point moves on the test sample according to the scanning direction, scanning the test sample. After the test sample is illuminated, a light signal is generated. This light signal is transmitted to the photoelectric detection module 130 through the imaging lens 122. Different pixels of the photoelectric detection module 130 receive light signals from different positions on the test sample. As time progresses, the electrical signals of pixel 1, pixel 2, and pixel 3 are obtained sequentially, and finally, the image of the test sample is reconstructed using these electrical signals.

[0079] This embodiment of the application achieves precise excitation and imaging of the test sample in this manner, ensuring the clarity and resolution of the image. Simultaneously, it ensures the temporal separation of light pulses of different wavelengths, overcoming the spectral crosstalk problem of traditional beam splitting paths.

[0080] Figure 10 The diagram shown is a schematic representation of the structure of a photoelectric detection module provided in an exemplary embodiment of this application; as shown Figure 10 As shown, the photoelectric detection module 130 provided in this application embodiment includes: at least one photoelectric detector 131, configured to convert an optical signal into an initial electrical signal; and an amplifier 132, configured to amplify the initial electrical signal to obtain an electrical signal.

[0081] In an exemplary embodiment of this application, the photodetector 131 includes at least one of a photodiode, a photomultiplier tube, and a silicon photomultiplier detector. A photodetector is a sensor that converts an optical signal into an electrical signal. A photomultiplier tube is a vacuum electronic device that converts a weak optical signal into an electrical signal. A silicon photomultiplier detector is a photodetector composed of an array of avalanche photodiodes. An amplifier is a device that proportionally increases the amplitude of an input signal while preserving as much of the original waveform and characteristics of the signal as possible.

[0082] It should be noted that high-speed photodetectors such as photodiodes (PDDs) and photomultiplier tubes can achieve time response bandwidths up to the GHz level. Furthermore, for fluorescence imaging, the fluorescence lifetime of fluorescent molecules is typically a few nanoseconds. The embodiments of this application can fully utilize the time bandwidth of the imaging detector without reducing the original time resolution of the scanning imaging system. Simultaneously, it eliminates the need for multi-wavelength spectroscopic detection, enabling multi-wavelength imaging with a single detector, significantly reducing the structural complexity of the multi-wavelength scanning imaging system and facilitating miniaturization for applications such as endoscopic imaging. Further, after the photodetector 131 converts the received optical signal into an initial electrical signal, since the amplitude of the initial electrical signal may be small, direct processing is difficult. Therefore, the initial electrical signal is amplified by amplifier 132 to improve the signal-to-noise ratio and processing effect. The output of amplifier 132 is connected to the time-domain splitting module 140 for subsequent time-domain splitting and processing of the electrical signal.

[0083] The photoelectric detection module provided in this application embodiment can effectively convert and amplify optical signals, ensuring signal quality during the imaging process. Furthermore, by employing high-performance detectors such as photodiodes, photomultiplier tubes, or silicon photomultiplier detectors, it can achieve sensitive detection of weak optical signals, improving imaging sensitivity and dynamic range.

[0084] In an exemplary embodiment of this application, the temporal domain splitting module realizes pixel splitting and multi-wavelength image reconstruction based on the scanning synchronization signal and the wavelength synchronization signal.

[0085] The scan synchronization signal is used to identify the scan time of each scan point; the wavelength synchronization signal is used to identify the arrival time of light pulses of different wavelengths in order to distinguish light signals of different wavelengths.

[0086] In this embodiment, the temporal domain splitting module splits the electrical signal corresponding to each pixel based on the scanning synchronization signal; according to the wavelength synchronization signal, the split electrical signal is split again to obtain the imaging signal corresponding to each pixel for different wavelengths, and image reconstruction is performed with the imaging signal.

[0087] The embodiments of this application can accurately distinguish the electrical signals corresponding to light pulses of different wavelengths, thereby determining the imaging signal corresponding to each pixel, providing clear and accurate information for image reconstruction, and helping to generate high-quality multi-wavelength scanning imaging results.

[0088] Specifically, the time-domain splitting module 140 is built on a programmable gate array or a data acquisition card with synchronous timing input.

[0089] Programmable gate arrays (PGAs) are highly integrated digital circuits with powerful logic processing capabilities and high flexibility. They can be configured to perform different functions as needed.

[0090] A data acquisition card with synchronous timing input is a device specifically designed for data acquisition, characterized by high precision and high speed. The acquisition card accurately acquires and stores the input electrical signals for subsequent data processing and analysis.

[0091] This application embodiment constructs a time-domain splitting module using a programmable gate array (PGA) or a data acquisition card with synchronous timing inputs. This enables precise timing control of the optical pulse sequence, ensuring the stability and reliability of the time-domain splitting module and improving the overall performance of the imaging system. Furthermore, the time-domain splitting module constructed based on a PGA or a data acquisition card with synchronous timing inputs has strong anti-interference capabilities and can operate normally under complex environmental conditions.

[0092] In certain fluorescence imaging applications, due to the broad excitation and collection spectra of fluorescence, this application provides an imaging method that combines multi-wavelength scanning imaging with a traditional spectral splitting optical path to maximize the signal-to-noise ratio and image separation of multi-wavelength fluorescence imaging. By using multiple detectors with bandpass filters in conjunction with the time-domain splitting method provided in this application, high signal-to-noise ratio multi-wavelength fluorescence imaging results can be obtained.

[0093] Figure 11 The diagram shown is a schematic flowchart of a multi-wavelength scanning imaging method provided in an exemplary embodiment of this application. Figure 11 As shown, the imaging method includes the following steps.

[0094] Step S1110: Determine the imaging area of ​​the target sample;

[0095] Step S1120: Based on any embodiment of the multi-wavelength scanning imaging system of this application, a scanning image of the imaging area corresponding to light pulses of different wavelengths is generated.

[0096] The multi-wavelength scanning imaging system in this embodiment can acquire optical signals corresponding to light pulses of all wavelengths without using multiple photoelectric detection modules. Furthermore, because the multi-wavelength scanning imaging system employs time-sequence separation, it avoids spectral crosstalk issues, which helps improve the accuracy of target sample imaging results.

[0097] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0098] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0099] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0100] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0101] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A multi-wavelength scanning imaging system, comprising: A light source module is configured to output a target pulse sequence, the target pulse sequence comprising multiple light pulses of different wavelengths separated in the time domain, wherein the repetition frequency of each light pulse of a wavelength is greater than the pixel frequency, such that each pixel time contains at least one set of the target pulse sequence; The scanning imaging module is configured to receive the target pulse sequence, focus the target pulse sequence onto the test sample and scan it using a point-by-point scanning method; A photoelectric detection module is configured to receive an optical signal generated by the test sample in response to the target pulse sequence and convert the optical signal into an electrical signal. The time response bandwidth of the photoelectric detection module is greater than the ratio of the number of optical pulses contained in the target pulse sequence to the pixel time. The time-domain splitting module is configured to split the electrical signal according to pixel time; within each pixel time, based on the timing of multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is split in the time domain to obtain the imaging signal of each pixel point, so as to reconstruct the multi-wavelength image of the test sample. The pixel time represents the time that the scanning point stays on each pixel point during the point-by-point scanning process of the scanning imaging module. The scanning process records the number of target pulse sequences illuminating each pixel. Within each pixel time interval, based on the timing of multiple light pulses of different wavelengths in the target pulse sequence, the electrical signal is temporally decomposed to obtain the imaging signal for each pixel, including: For each pixel, the split electrical signal is further split according to the number of target pulse sequences and the timing of multiple light pulses of different wavelengths in the target pulse sequences. The split electrical signals are analyzed and processed to obtain the imaging signals corresponding to different wavelengths for that pixel. The imaging signals are used to reflect the imaging parameters of the test sample at that pixel.

2. The multi-wavelength scanning imaging system according to claim 1, characterized in that, The light source module includes: At least one light source is configured to output illumination light of multiple different wavelengths, the illumination light including continuous illumination light or pulsed illumination light; An optical power modulator is configured to perform time-on-off modulation on the plurality of illumination lights of different wavelengths to generate the target pulse sequence; The time response bandwidth of the optical power modulator is greater than the ratio of the pixel time to the number of wavelengths of the illumination light.

3. The multi-wavelength scanning imaging system according to claim 1, characterized in that, The light source module includes: A multi-wavelength synchronous pulse laser, configured to output multiple optical pulses of different wavelengths; The timing adjustment unit is configured to adjust the relative time delay between the plurality of optical pulses of different wavelengths to generate the target pulse sequence; The multi-wavelength synchronous pulse laser outputs optical pulses of all wavelengths with the same repetition frequency and constant phase delay.

4. The multi-wavelength scanning imaging system according to claim 3, characterized in that, The timing adjustment unit achieves the relative time delay of the multiple light pulses of different wavelengths by adjusting the optical path difference of the multiple light pulses of different wavelengths.

5. The multi-wavelength scanning imaging system according to claim 3, characterized in that, The timing adjustment unit achieves the relative time delay of the multiple optical pulses of different wavelengths by adjusting the fiber lengths corresponding to each of the multiple optical pulses of different wavelengths.

6. The multi-wavelength scanning imaging system according to any one of claims 1 to 5, characterized in that, The photoelectric detection module includes: At least one photodetector is configured to convert the optical signal into an initial electrical signal; An amplifier configured to amplify the initial electrical signal to obtain the electrical signal.

7. The multi-wavelength scanning imaging system according to any one of claims 1 to 5, characterized in that, The scanning imaging module includes a uniform point-by-point scanning mode and a non-uniform point-by-point scanning mode. The point-by-point scanning method includes one of the following: grid scanning method, Lissajous scanning method, spiral scanning method, and hexagonal scanning method.

8. The multi-wavelength scanning imaging system according to any one of claims 1 to 5, characterized in that, The scanning imaging module includes at least one of a laser scanning confocal microscope, a multiphoton imaging system, and an optical coherence tomography system; The target pulse sequence enters the scanning imaging module through a free-space optical path or optical fiber.

9. The multi-wavelength scanning imaging system according to any one of claims 1 to 5, characterized in that, The time-domain splitting module uses scanning synchronization signals and wavelength synchronization signals to split the pixels and reconstruct multi-wavelength images.

Images