An ultrafast single-pixel imaging device and method

Abstract

The application discloses a kind of super high-speed single-pixel imaging device and method, including two-dimensional space disperser, dispersion compensation optical fiber, Mach-Zehnder modulator, single-mode optical fiber and photoelectric sensor;Based on super high-speed two-dimensional space light modulation light path, the mapping of frequency spectrum and space signal and the mapping of frequency spectrum and time domain signal are carried out, the mapping of space signal and time domain signal is completed;The light intensity of modulated light is measured by super high-speed photoelectric sensor;The imaging object is directly recovered from the correlation of light intensity value by Hadamard single-pixel imaging algorithm.The application realizes the two-dimensional single-pixel imaging of megahertz level, consistent two-axis resolution, solves the defect of low spatial and temporal resolution in single-pixel imaging, and helps the application of single-pixel imaging technology in more practical fields.

Description

Technical Field

[0001] This invention relates to an ultra-high-speed single-pixel imaging device and method, belonging to the field of computational imaging. Background Technology

[0002] Imaging technology is one of the most important means for humans to acquire information. Its essence lies in using detectors to sample the spatial distribution of continuous electromagnetic fields carrying signals. The most traditional imaging method is the camera based on the pinhole imaging principle. Due to its use of two-dimensional array sensors, which offer extremely high efficiency and low cost in the visible light band, it has become the most widely used method. However, if imaging in non-visible light bands is required, a trade-off must usually be struck between the cost of the two-dimensional array sensor, the required final image resolution, and the necessary readout speed.

[0003] In contrast to traditional imaging techniques, computational imaging techniques utilize extensive mathematical algorithms to overcome long-standing limitations in traditional imaging methods. Single-pixel imaging is a type of computational imaging that, based on the principle of correlation measurement, uses a spatial light modulator for structured light illumination at the illumination end, a single photoelectric sensor without spatial resolution to collect light intensity information at the measurement end, and an algorithm for image reconstruction at the computation end. Because single-pixel cameras only require light intensity detection at the detection end, their requirements for the detector are far lower than those of two-dimensional array sensors used in conventional imaging. Therefore, single-pixel imaging technology offers significant advantages in wavelengths where two-dimensional array sensor technology is still immature, and has thus garnered considerable attention.

[0004] However, due to the limited modulation rate of existing spatial light modulators and the massive number of structured light modulations required for single-pixel imaging, single-pixel imaging technology is far inferior to traditional imaging technologies in both temporal and spatial resolution, which limits its application in production practice. Therefore, it is necessary to design an ultra-high-speed single-pixel imaging device to solve the problem of its low imaging efficiency.

[0005] Currently, there are three main types of techniques commonly used in the field of single-pixel imaging to improve imaging efficiency. First, reducing the number of structured light intensity measurements required: using compressed sensing algorithms to achieve imaging below the Nyquist sampling limit; for the same correlation algorithm, using a more optimized sampling path, combined with machine learning algorithms, to achieve high-quality imaging at a lower sampling rate. However, given the limited speed of spatial light modulators, these techniques only address the symptoms, not the root cause. Second, using spatial light modulators with higher modulation rates, such as digital micromirror arrays (10kHz level) or LED arrays (100kHz level). However, for single-pixel imaging technology where measurement requirements increase exponentially with imaging size, such limited modulation rates are still insufficient. Furthermore, these spatial light modulators typically limit the spatial resolution of single-pixel imaging. The third method utilizes time-stretching and one-dimensional spatial light discretization techniques. By establishing the correlation between the light spectrum, time series, and spatial location, ultra-high-speed one-dimensional modulation of spatial light and subsequent one-dimensional computational imaging are achieved using high-frequency laser pulses and Mach-Zehnder modulators. Two-dimensional imaging can be achieved based on one-dimensional imaging using a one-dimensional precision displacement stage. This method can achieve imaging efficiency at the megahertz level. However, since it is essentially a one-dimensional imaging method, its spatial resolution on the x-axis and y-axis is different. Therefore, it is only suitable for specific scenarios such as flow cytometry observation and cannot be more widely applied to more practical scenarios. Summary of the Invention

[0006] The technical problem solved by this invention is to provide an ultra-high-speed single-pixel imaging device and method that addresses the shortcomings of existing technologies. Based on the principles of time stretching and two-dimensional spatial light discretization, it achieves spatial light modulation efficiency at the MHz or even GHz level, fundamentally improving the spatiotemporal resolution of single-pixel imaging technology.

[0007] Technical solution of the present invention:

[0008] In a first aspect, the present invention provides an ultra-high-speed single-pixel imaging device, comprising: a two-dimensional spatial discretizer, a dispersion-compensating fiber, a Mach-Zehnder modulator, a single-mode fiber, and a photoelectric sensor.

[0009] Two-dimensional spatial discretizer: The laser pulse signal and the two-dimensional reflectivity distribution of the target object to be imaged are mapped in a spectrum-spatial domain to obtain the laser pulse signal after spectrum-spatial domain mapping;

[0010] Dispersion-compensating fiber: The laser pulse signal after spectrum-spatial mapping is time-stretched to complete the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, and obtain the stretched laser pulse signal with spectrum-time domain mapping.

[0011] Mach-Zehnder modulator: As an ultra-high-speed controllable optical switch, it performs binary modulation on the time series of stretched laser pulse signals with spectrum-time domain mapping based on the Hadamard matrix, indirectly realizing two-dimensional Hadamard modulation of spatial light; and obtains the time series after binary modulation.

[0012] Single-mode fiber: The time series after binary modulation is compressed to obtain the modulated laser pulse signal;

[0013] Photoelectric sensor: measures the total light intensity of the modulated laser pulse signal, and recovers the imaging object based on the correlation of the total light intensity value using the Hadamard single-pixel imaging algorithm. The imaging object is a two-dimensional imaging object with consistent resolution on both axes, namely the x-axis and the y-axis.

[0014] Secondly, this invention provides an ultra-high-speed single-pixel imaging method, which is implemented as follows:

[0015] S1: A two-dimensional spatial discretizer is used to perform spectrum-spatial mapping on the laser pulse signal and the two-dimensional distribution of reflectivity of the target object to be imaged, so as to obtain the laser pulse signal after spectrum-spatial mapping.

[0016] S2: Dispersion compensation fiber, which performs time stretching on the pulse signal after spectrum-spatial mapping, completes the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, and obtains the stretched laser pulse signal with spectrum-time mapping;

[0017] S3: Using a Mach-Zehnder modulator as an ultra-high-speed controllable optical switch, the time series of the stretched laser pulse signal with spectrum-time domain mapping is binarized based on the Hadamard matrix to indirectly realize two-dimensional Hadamard modulation of spatial light; the time series after binarization is obtained.

[0018] S4: Use single-mode fiber to compress the binary modulated time series to obtain the modulated laser pulse signal;

[0019] S5: The total light intensity of the modulated laser pulse signal is measured using a photoelectric sensor, and the imaging object is recovered based on the correlation of the total light intensity value using a Hadamard single-pixel imaging algorithm. The imaging object is a two-dimensional imaging object with consistent resolution on both axes, namely the x-axis and the y-axis.

[0020] Thirdly, the present invention provides another ultra-high-speed single-pixel imaging device, comprising:

[0021] Mode-locked laser (MLL),

[0022] Mach-Zehnder modulator (MZM),

[0023] Photoelectric sensor (PD),

[0024] Multiple pre-amplified erbium-doped fiber amplifiers (EDFAs),

[0025] At least one section of dispersion-compensating fiber (DCF),

[0026] Fiber optic circulator (Cir),

[0027] Two-dimensional spatial discretizer (2D-SD);

[0028] The laser pulse signal output by the mode-locked laser is coupled to the first pre-amplified erbium-doped fiber amplifier via a multimode fiber, and then coupled to a fiber circulator via another multimode fiber. The laser pulse output from the fiber circulator is incident on a two-dimensional spatial discretizer, which performs a spectral-spatial mapping on the laser pulse signal and the two-dimensional reflectivity distribution of the target object. The laser pulse signal output from the two-dimensional spatial discretizer is incident on the surface of the target object and is reflected. The reflected discrete laser pulse signal returns to the surface of the two-dimensional spatial discretizer, and is integrated by the two-dimensional spatial discretizer into a spectral-spatial mapped pulse signal, which is then sent to the fiber circulator. An optical fiber circulator is coupled to a second pre-amplified erbium-doped fiber amplifier via a multimode fiber. The output of the second pre-amplified erbium-doped fiber amplifier is connected to a Mach-Zehnder modulator via a dispersion-compensating fiber. The dispersion-compensating fiber performs time stretching on the spectrum-spatial-domain mapped pulse signal, completing the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, resulting in a stretched pulse signal with spectrum-time domain mapping. The Mach-Zehnder modulator, acting as an ultra-high-speed controllable optical switch, performs binary modulation on the time sequence of the stretched pulse signal with spectrum-time domain mapping based on the Hadamard matrix, indirectly realizing two-dimensional Hadamard modulation of spatial light, and obtaining a binary modulated signal. The time series after binary modulation is coupled to a third erbium-doped fiber amplifier via a multimode fiber, and then coupled to a fourth erbium-doped fiber amplifier via a single-mode fiber. The single-mode fiber compresses the binary-modulated time series to obtain a modulated pulse signal. The fourth erbium-doped fiber amplifier couples the modulated pulse signal to the target surface of the photoelectric sensor via a multimode fiber. The photoelectric sensor measures the total light intensity of the modulated pulse signal. Based on the correlation of the total light intensity value, the Hadamard single-pixel imaging algorithm is used to recover a two-dimensional imaging object with consistent resolution on the x-axis and y-axis.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The spatial light modulator used in traditional single-pixel imaging technology has a low modulation rate, so it can only achieve two-dimensional single-pixel imaging at the KHz level. However, this invention utilizes the ultra-high time series modulation capability of the Mach-Zehnder modulator to achieve two-dimensional single-pixel imaging at at least the MHz level. Its efficiency is much higher than that of traditional two-dimensional single-pixel imaging technology, so it can fundamentally improve the spatiotemporal resolution of single-pixel imaging technology.

[0031] (2) Traditional ultra-high-speed single-pixel imaging technology uses time stretching technology and one-dimensional spatial discretizers to achieve ultra-high-speed one-dimensional imaging, and further uses a precision displacement stage to achieve two-dimensional imaging; however, its X-axis and Y-axis spatial resolutions are inconsistent, so it is only suitable for streaming observation, with limited application scenarios, and is not suitable for tracking high-speed moving objects. In contrast, this invention uses a two-dimensional spatial light discretizer to achieve two-dimensional imaging with consistent X-axis and Y-axis resolutions, and is suitable for tracking high-speed moving objects, thus having the advantage of being applicable to a wider range of application scenarios. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the optical path of the ultra-high-speed single-pixel imaging device of the present invention;

[0033] Figure 2 This is a flowchart of the ultra-high-speed single-pixel imaging method of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific implementations and in conjunction with the accompanying drawings.

[0035] like Figure 1 As shown, the ultra-high-speed single-pixel imaging device provided in this embodiment of the invention includes:

[0036] Mode-locked laser (MLL) 101; a high repetition rate mode-locked laser can emit narrowband pulse waves at a repetition rate of 100M-1GHz; in this embodiment, it is used as a light source;

[0037] Fiber optic circulator (Cir) 102; a fiber optic circulator is a multi-port non-reciprocal optical device in which light can only propagate in a predetermined direction; in this embodiment, it is used to distinguish between illumination light and return light. Illumination light is shown as a solid arrow, and reflected light is shown as a dashed arrow.

[0038] A two-dimensional spatial light discretizer (2D-SD) 103, composed of a virtual image phase array (VIPAs) and a blazed grating (BG), can discretize point incident light into two-dimensional planar light according to the spectrum; in this embodiment, it is used to complete the mapping between the laser spectrum and the spatial distribution of the object's reflectivity.

[0039] Mach-Zehnder modulator (MZM) 104: performs binary amplitude modulation of the optical signal into 0 or 1 according to the Mach-Zehnder interference principle; in this embodiment, it is used to load the encoding of single-pixel imaging technology into the optical signal.

[0040] Multimode fiber (MMF) 105; located between any two optical components, used to transmit optical signals with low loss;

[0041] The erbium-doped fiber amplifier (EDFA) 106 is located between two fiber segments and compensates for signal loss during fiber transmission; in this embodiment, it is used to improve the signal-to-noise ratio of the final image.

[0042] Dispersion-compensating fiber (DCF) 107: A fiber with large negative dispersion, located between a fiber circulator and a Mach-Zehnder modulator. Light of different frequency bands will have different propagation speeds in the dispersion-compensating fiber. In this embodiment, it is used to map the laser spectrum and the time sequence of the optical signal arriving at the Mach-Zehnder modulator. Together with the two-dimensional spatial light discretizer and the Mach-Zehnder modulator, it completes two-dimensional spatial light modulation.

[0043] Single-mode fiber (SMF) 108; located between the Mach-Zehnder modulator and the final PD, used to recompress the stretched optical signal into a pulse signal;

[0044] The photoelectric sensor (PD) 109 is located at the end of the experimental setup and is used to measure the intensity of the returned light.

[0045] The ultra-high-speed single-pixel imaging device proposed in this embodiment uses a Mach-Zehnder modulator to perform binary modulation on the time-domain signal. Since the time-domain and spatial-domain mapping has been indirectly completed through spectrum mapping, the device can operate at the lowest bandwidth of the mode-locked laser, Mach-Zehnder modulator, and photoelectric sensor. By selecting appropriate equipment, the device of this embodiment can achieve spatial light modulation rates at the MHz or even GHz level, which greatly improves the time efficiency of single-pixel imaging.

[0046] Example 2

[0047] Based on the aforementioned ultra-high-speed two-dimensional spatial light modulation optical path, single-pixel imaging above megahertz was achieved using Hadamard single-pixel imaging technology, as follows: Figure 2 As shown, the specific steps are as follows:

[0048] S1: A two-dimensional spatial discretizer is used to perform spectrum-spatial mapping on the laser pulse signal and the two-dimensional distribution of reflectivity of the target object to be imaged, so as to obtain the laser pulse signal after spectrum-spatial mapping.

[0049] The object under test is placed in a light-proof environment. The light emitted by the mode-locked laser is discrete by a two-dimensional spatial light discretizer and then shines on the object under test. The discrete light of different frequencies will fall on different spatial positions of the object. The reflected light is integrated by the two-dimensional spatial light discretizer and then re-enters the fiber optic circulator for further processing.

[0050] S2: Dispersion compensation fiber, which performs time stretching on the pulse signal after spectrum-spatial mapping, completes the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, and obtains the stretched laser pulse signal with spectrum-time mapping;

[0051] S3: Using a Mach-Zehnder modulator as an ultra-high-speed controllable optical switch, the time series of the stretched laser pulse signal with spectrum-time domain mapping is binarized based on the Hadamard matrix to indirectly realize two-dimensional Hadamard modulation of spatial light; the time series after binarization is obtained.

[0052] The time sequence of light passing through the Mach-Zehnder modulator originates from different locations on the surface of the object under test, thus establishing a correlation between spatial and temporal information. Therefore, a Hadamard modulation template P(x,y) can be added to the temporal signal using a Mach-Zehnder sensor.

[0053]

[0054] Where (x,y) represents the two-dimensional coordinates in the spatial domain, H -1 {·} represents the inverse Hadamard transform, δ{·} represents the Dirac function, and (u,v) represents the coordinates in the Hadamard spectrum. Since the device in this embodiment can only achieve modulation of 0 and 1, and the Hadamard template is composed of -1 and 1 elements, the difference method is used to characterize P(x,y).

[0055]

[0056] Assuming the intensity distribution of the two-dimensional image to be measured is I(x,y), then the modulated light energy E is equal to the inner product of I(x,y) and P(x,y), which can be expressed by the following formula:

[0057] E + -E-=I(x,y)·(P + (x,y)-P-(x,y)) (3)

[0058] S4: Use single-mode fiber to compress the binary modulated time series to obtain the modulated laser pulse signal;

[0059] S5: Use a photoelectric sensor to measure the total light intensity of the modulated laser pulse signal, and use the Hadamard single-pixel imaging algorithm to recover the imaging object based on the correlation of the total light intensity value.

[0060] If D represents the response of the photoelectric sensor to the modulated reflected energy E, this response, as shown in the following equation, contains two parts.

[0061] D = m·E + D n (4)

[0062] Among them, D n For environmental noise, since the measurement time interval is extremely short, the environmental noise is considered to have not changed, so formula (3) is further expressed as:

[0063] H(u,v)=m·(E + (u,v)-E-(u,v)) (5)

[0064] Where H(u,v) is the Hadamard spectrum value of the object under test, and m is the response coefficient of the photoelectric sensor to light intensity.

[0065] After measuring all the spectral values, perform an inverse Hadamard transform on the obtained Hadamard spectrum, and normalize the amplitude of the inverse transform result to eliminate the influence of the sensor coefficient m, thus obtaining the pattern to be measured.

[0066] In summary, this invention utilizes an ultra-high-speed two-dimensional spatial light modulation optical path to map spectral and spatial signals, as well as spectral and temporal signals, thus completing the mapping between spatial and temporal signals. It measures the intensity of the modulated light using an ultra-high-speed photoelectric sensor and directly recovers the imaged object from the correlation of light intensity values ​​using a Hadamard single-pixel imaging algorithm. This invention achieves megahertz-level two-dimensional single-pixel imaging with consistent two-axis resolution, overcoming the low spatiotemporal resolution of single-pixel imaging and facilitating its application in more practical fields.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] Or it may implicitly indicate the number of indicated technical features. Thus, features defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0070] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-speed single-pixel imaging device, characterized in that, Based on the principles of time stretching and two-dimensional spatial light discretization, spatial light modulation efficiency at the MHz and even GHz levels is achieved; and two-dimensional imaging with consistent X-axis and Y-axis resolution is realized, which is suitable for tracking high-speed moving objects. The device includes: a two-dimensional spatial discretizer, a dispersion-compensating fiber, a Mach-Zehnder modulator, a single-mode fiber, and a photoelectric sensor; Two-dimensional spatial discretizer: The laser pulse signal and the two-dimensional reflectivity distribution of the target object to be imaged are mapped in a spectrum-spatial domain to obtain the laser pulse signal after spectrum-spatial domain mapping; Dispersion-compensating fiber: The laser pulse signal after spectrum-spatial mapping is time-stretched to complete the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, and obtain the stretched laser pulse signal with spectrum-time domain mapping. Mach-Zehnder modulator: As an ultra-high-speed controllable optical switch, it performs binary modulation on the time series of stretched laser pulse signals with spectrum-time domain mapping based on the Hadamard matrix, indirectly realizing two-dimensional Hadamard modulation of spatial light; and obtains the time series after binary modulation. Single-mode fiber: The time series after binary modulation is compressed to obtain the modulated laser pulse signal; Photoelectric sensor: measures the total light intensity of the modulated laser pulse signal, and recovers a two-dimensional imaging object with consistent x-axis and y-axis resolution based on the correlation of the total light intensity value using the Hadamard single-pixel imaging algorithm; The discrete laser pulses reflected by the object under test first return to the two-dimensional spatial discretizer and are integrated into a pulse signal carrying the two-dimensional reflectivity distribution of the object under test after spectral-spatial mapping. Then, the pulses are output to the dispersion compensation fiber through the fiber circulator to complete the spectral-time mapping. Subsequently, the time series carrying the two-dimensional spatial information of the target is subjected to Hadamard binary modulation by the Mach-Zehnder modulator in the receiving optical path. The Hadamard template consists of -1 and 1 elements, and the difference method is used to characterize the Hadamard spectrum value; After measuring all spectral values, an inverse Hadamard transform was performed on the Hadamard spectrum, and the amplitude of the inverse transform result was normalized to eliminate the influence of the photoelectric sensor response coefficient.

2. The ultra-high-speed single-pixel imaging device according to claim 1, characterized in that, The device also includes: a mode-locked laser, multiple pre-amplified erbium-doped fiber amplifiers, and a fiber optic circulator; The laser pulse signal output from the mode-locked laser is coupled to a first pre-amplified erbium-doped fiber amplifier via a multimode fiber, and then coupled to a fiber circulator via another multimode fiber. The laser pulse output from the fiber circulator is incident on a two-dimensional spatial discretizer, which performs spectral-spatial mapping on the laser pulse signal and the two-dimensional reflectivity distribution of the target object. The laser pulse signal emitted from the two-dimensional spatial discretizer is incident on the surface of the target object and reflected. The reflected discrete laser pulse signal returns to the surface of the two-dimensional spatial discretizer, where it is integrated into a spectral-spatial mapped pulse signal and sent to the fiber circulator. The fiber circulator is coupled to a second pre-amplified erbium-doped fiber amplifier via a multimode fiber. The output of the second pre-amplified erbium-doped fiber amplifier is connected to a Mach-Zehnder modulator via a dispersion-compensating fiber. The dispersion-compensating fiber performs time stretching on the spectral-spatial mapped pulse signal, completing the spectral and optical signal arrival... A spectrum-time domain mapping is performed to obtain a stretched pulse signal with the spectrum-time domain mapping. A Mach-Zehnder modulator, acting as an ultra-high-speed controllable optical switch, performs binary modulation on the time sequence of the stretched pulse signal based on the Hadamard matrix, indirectly achieving two-dimensional Hadamard modulation of spatial light and obtaining a binary modulated time sequence. The binary modulated time sequence is coupled to a third pre-amplified erbium-doped fiber amplifier via a multimode fiber, and then coupled to a fourth pre-amplified erbium-doped fiber amplifier via a single-mode fiber. The single-mode fiber compresses the binary modulated time sequence to obtain a modulated pulse signal. The fourth pre-amplified erbium-doped fiber amplifier finally couples the modulated pulse signal to the target surface of a photoelectric sensor via a multimode fiber. The photoelectric sensor measures the total light intensity of the modulated pulse signal, and using a Hadamard single-pixel imaging algorithm, based on the correlation of the total light intensity value, recovers a two-dimensional imaging object with consistent x-axis and y-axis resolution.

3. A method for ultra-high-speed single-pixel imaging, characterized in that, Based on the principles of time stretching and two-dimensional spatial light discretization, spatial light modulation efficiency at the MHz or even GHz level is achieved, and two-dimensional imaging with consistent X-axis and Y-axis resolution is realized, which is suitable for tracking objects moving at high speeds. The method is implemented as follows: S1: A two-dimensional spatial discretizer is used to perform spectrum-spatial mapping on the laser pulse signal and the two-dimensional distribution of reflectivity of the target object to be imaged, so as to obtain the laser pulse signal after spectrum-spatial mapping. S2: Dispersion compensation fiber, which performs time stretching on the pulse signal after spectrum-spatial mapping, completes the spectrum-time domain mapping of the spectrum and the arrival time of the optical signal, and obtains the stretched laser pulse signal with spectrum-time mapping; S3: Using a Mach-Zehnder modulator as an ultra-high-speed controllable optical switch, the time sequence of the stretched laser pulse signal with spectrum-time domain mapping is binary modulated based on the Hadamard matrix, thereby indirectly realizing two-dimensional Hadamard modulation of spatial light. The time series after binary modulation is obtained; S4: Use single-mode fiber to compress the binary modulated time series to obtain the modulated laser pulse signal; S5: Use a photoelectric sensor to measure the total light intensity of the modulated laser pulse signal, and use the Hadamard single-pixel imaging algorithm to recover a two-dimensional imaging object with consistent x-axis and y-axis resolution based on the correlation of the total light intensity value; The discrete laser pulses reflected by the object under test first return to the two-dimensional spatial discretizer and are integrated into a pulse signal carrying the two-dimensional reflectivity distribution of the object under test after spectral-spatial mapping. Then, the pulses are output to the dispersion compensation fiber through the fiber circulator to complete the spectral-time mapping. Subsequently, the time series carrying the two-dimensional spatial information of the target is subjected to Hadamard binary modulation by the Mach-Zehnder modulator in the receiving optical path. The Hadamard template consists of -1 and 1 elements, and the difference method is used to characterize the Hadamard spectrum value; After measuring all spectral values, an inverse Hadamard transform was performed on the Hadamard spectrum, and the amplitude of the inverse transform result was normalized to eliminate the influence of the photoelectric sensor response coefficient.

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