Single-pixel imaging method and device for single acquisition
Through the combination of photoacoustic effects and trained mapping models, single-pixel imaging is realized, which solves the problem of low imaging speed in the prior art and realizes imaging of fast moving objects.
Patent Information
- Application Number
- CN202510188145.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-06-10
AI Technical Summary
The existing single-pixel imaging technology has low imaging speed and is unable to image fast moving objects.
Through photoacoustic effect, the target ultrasonic timing signal corresponding to the pulse beam carrying the information of the object to be measured is collected in a single time, and the information of the object to be measured is reconstructed using the trained mapping model to achieve single-pixel imaging.
The imaging speed is improved and the imaging of fast moving objects is achieved.
Smart Images
Figure CN120121089A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of imaging technology, and particularly to a single-pixel imaging method and device for single-shot acquisition. Background Art
[0002] Traditional cameras usually use a two-dimensional array composed of multiple detector pixels to capture images. Single-pixel imaging technology is an imaging technology based on light field modulation and aliasing information detection, and finally realizes image reconstruction through calculation. It is favored by people because of its unique imaging principle, low energy consumption, small volume, low computational complexity, and low requirements for detectors.
[0003] Existing single-pixel imaging usually requires structured light illumination and a single-pixel detector for imaging. Therefore, multiple acquisitions are required during the imaging process, resulting in a low imaging speed and the problem of being unable to image fast-moving objects.
[0004] Therefore, how to improve the imaging speed is an urgent problem to be solved by those skilled in the art. Summary of the Invention
[0005] Based on the above problems, this application provides a single-pixel imaging method and device for single-shot acquisition, which utilizes the photoacoustic effect to realize single-pixel imaging for single-shot acquisition through single-point single-shot detection, thereby improving the imaging speed.
[0006] In a first aspect, an embodiment of this application provides a single-pixel imaging method for single-shot acquisition, including: single-shot acquisition of a target ultrasonic time series signal corresponding to a pulsed beam carrying information of an object to be measured;
[0007] Based on the target ultrasonic time series signal, use a trained mapping model to reconstruct the optical pattern corresponding to the object to be measured and obtain a target image.
[0008] Optionally, before the single-shot acquisition of the target ultrasonic time series signal corresponding to the pulsed beam carrying information of the object to be measured, it further includes:
[0009] Obtain a pulsed beam carrying information of the object to be measured through a photoacoustic converter, and convert the optical signal corresponding to the pulsed beam into a first ultrasonic time series signal.
[0010] Optionally, the method further includes:
[0011] Control the first ultrasonic time series signal to be reflected in an anisotropic acoustic cavity;
[0012] The single-shot acquisition of the target ultrasonic time series signal corresponding to the pulsed beam carrying information of the object to be measured includes:
[0013] Through an ultrasonic transducer, the first ultrasonic timing signal reflected in the acoustic cavity is collected once, and a target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured is obtained.
[0014] Optionally, the length of the target ultrasonic timing signal is 2.4 microseconds.
[0015] Optionally, based on the target ultrasonic timing signal, using a trained mapping model to reconstruct the optical pattern corresponding to the object to be measured, and obtaining a target image, including:
[0016] Converting the target ultrasonic timing signal into a target digital signal through a signal acquisition card;
[0017] Based on the target digital signal, using a trained mapping model to reconstruct the optical pattern corresponding to the object to be measured, and obtaining a target image.
[0018] Optionally, the mapping model is trained by the following method:
[0019] Obtaining the ultrasonic waveform of the training ultrasonic timing signal corresponding to the optical image;
[0020] Training a U-Net model based on the ultrasonic waveform and the optical image, and obtaining a trained mapping model.
[0021] Optionally, the obtaining the ultrasonic waveform of the training ultrasonic timing signal corresponding to the optical image includes:
[0022] Converting the optical signal corresponding to the optical image in the training set into a second ultrasonic timing signal;
[0023] Controlling the second ultrasonic timing signal to be reflected in the anisotropic acoustic cavity;
[0024] Through an ultrasonic transducer, the second ultrasonic timing signal reflected in the acoustic cavity is collected once, and a training ultrasonic timing signal corresponding to the light field is obtained;
[0025] Converting the training ultrasonic timing signal into a digital signal through a signal acquisition card;
[0026] Determining the ultrasonic waveform of the training ultrasonic timing signal based on the data signal.
[0027] In a second aspect, an embodiment of the present application provides a single-pixel imaging device for single acquisition, including:
[0028] An acquisition module, configured to single-acquire a target ultrasonic timing signal corresponding to a pulsed light beam carrying the information of the object to be measured;
[0029] A reconstruction module, configured to reconstruct an optical pattern corresponding to the object to be measured based on the target ultrasonic time series signal by using a trained mapping model, and obtain a target image.
[0030] As can be seen from the above technical solutions, compared with the prior art, the present application has the following advantages:
[0031] The present application first collects a target ultrasonic time series signal corresponding to a pulsed light beam carrying the information of the object to be measured once. Then, based on the target ultrasonic time series signal, the information of the object to be measured is reconstructed by using a trained mapping model, and a single-pixel image is obtained. In this way, by utilizing the photoacoustic effect, single-pixel imaging with single-point single-shot detection is achieved, thereby improving the imaging speed. Description of the Drawings
[0032] Figure 1 A schematic diagram of a microscopic device provided by an embodiment of the present application;
[0033] Figure 2 A flowchart of a single-pixel imaging method with single-shot acquisition provided by an embodiment of the present application;
[0034] Figure 3 A schematic diagram of an ultrasonic signal provided by an embodiment of the present application;
[0035] Figure 4 An imaging effect diagram provided by an embodiment of the present application;
[0036] Figure 5 A schematic structural diagram of a single-pixel imaging device with single-shot acquisition provided by an embodiment of the present application. Detailed Embodiments
[0037] As described above, the existing single-pixel imaging has the problem of low imaging speed. Specifically, the existing single-pixel imaging usually uses structured light illumination and a single-pixel detector for imaging. First, a series of temporally varying structured illumination lights are generated. After the illumination light passes through the object, the light intensity is collected by the single-pixel detector. Then, the reconstruction of the object is realized through the calculation of the pattern of the structured light and the light intensity signal. That is to say, the existing single-pixel imaging needs to perform multiple collections, which leads to a reduction in imaging speed and the problem of being unable to image fast-moving objects.
[0038] To solve the above problems, an embodiment of the present application provides a single-pixel imaging method with single-shot acquisition. The method first collects a target ultrasonic time series signal corresponding to a pulsed light beam carrying the information of the object to be measured once. Then, based on the target ultrasonic time series signal, the information of the object to be measured is reconstructed by using a trained mapping model, and a single-pixel image is obtained.
[0039] In this way, by utilizing the photoacoustic effect, single-pixel imaging with single-shot acquisition is achieved through single-point single-shot detection, thereby improving the imaging speed.
[0040] It should be noted that a single-shot single-pixel imaging method and device provided by this application can be applied to the field of imaging technology. The above is only an example, and it does not limit the application field of the single-shot single-pixel imaging method and device provided by this application.
[0041] In order to make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.
[0042] Figure 1 It is a schematic diagram of a microscopic device provided by an embodiment of this application. As shown in combination with Figure 1 The device includes three parts: an illumination optical system, a photoacoustic conversion system, and a single-pixel ultrasonic detection system. Among them, the illumination optical system includes a pulsed laser, a beam expansion system (L1 and L2), a mirror, a DMD, a beam reduction system with a small hole filter (L3, L4), and an object to be imaged. The beam reduction system is used to increase the light flux incident on the photoacoustic converter system, thereby increasing the signal intensity of the ultrasonic signal, and further improving the signal-to-noise ratio to achieve the purpose of optimizing imaging. In the model training stage, the object to be imaged in the optical path is removed, and an image is loaded on the DMD. In the imaging stage, the DMD is used as a mirror, and the object to be imaged is set in the optical path. The photoacoustic conversion system consists of a photoacoustic converter and an anisotropic acoustic cavity (water tank), where the photoacoustic converter is a light absorber made of an aluminum foil sheet. Finally, an ultrasonic signal is collected by a single-pixel ultrasonic probe (ultrasonic converter), and the electrical signal response value is output to the DAQ (signal acquisition card), and is converted into a digital signal by the DAQ and sent to a computer for analysis. The focal lengths of the various lenses in the device are as follows: L1 = 30mm, L2 = 300mm, L3 = 300mm, L4 = 100mm, L5 = 100mm, L6 = 50mm.
[0043] Figure 2 It is a flowchart of a single-shot single-pixel imaging method provided by an embodiment of this application. As shown in combination with Figure 2 The single-shot single-pixel imaging method provided by the embodiment of this application may include:
[0044] S201: Single-shot acquisition of the target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured.
[0045] Among them, the length of the target ultrasonic timing signal is 2.4 microseconds.
[0046] In practical applications, in combination with the above-mentioned microscopic device, the light emitted by the pulsed laser passes through a series of optical components and irradiates and passes through the object to be measured, and then based on the photoacoustic effect, the pulsed light beam carrying the information of the object to be measured is subjected to photoacoustic conversion to generate a corresponding ultrasonic signal. Finally, a single-pixel ultrasonic transducer is used to perform single-signal acquisition, and a target ultrasonic timing signal with a length of only 2.4 microseconds is collected from the ultrasonic signal and used for subsequent imaging. In this way, the purpose of single-pixel fast imaging is achieved.
[0047] In addition, since the methods of converting optical signals into ultrasonic signals are not all the same, the embodiments of the present application can illustrate one possible conversion method.
[0048] In one case, S201: Before single-shot acquisition of the target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured, it further includes:
[0049] Obtain the pulsed light beam carrying the information of the object to be measured through a photoacoustic converter, and convert the optical signal corresponding to the pulsed light beam into a first ultrasonic timing signal.
[0050] In practical applications, a photoacoustic converter is a technical device that converts light and sound waves into each other. It can convert optical signals into sound waves. According to the photoacoustic effect, when a photoabsorber is irradiated by a pulsed laser, due to the absorption of light energy, the temperature rises, and then sound waves are generated due to the thermoelastic effect. When irradiated by a pulsed optical signal with a specific two-dimensional distribution, ultrasonic signals corresponding to the distribution will be generated on the surface of the photoabsorber. The photoacoustic converter provided in the embodiments of the present application is a photoabsorber made of an aluminum foil sheet, which is arranged in the optical path of the pulsed light beam carrying the information of the object to be measured. The photoacoustic converter absorbs the pulsed light beam carrying the information of the object to be measured and converts the corresponding optical signal into an ultrasonic signal (the first ultrasonic timing signal).
[0051] In addition, since the methods of obtaining the target ultrasonic timing signal are not all the same, the embodiments of the present application can illustrate one possible obtaining method.
[0052] In one case, the method further includes:
[0053] Control the first ultrasonic timing signal to be reflected in the anisotropic acoustic cavity.
[0054] In one case, S201: Single-shot acquisition of the target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured specifically includes:
[0055] Through an ultrasonic transducer, the first ultrasonic timing signal reflected in the acoustic cavity is collected once, and a target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured is obtained.
[0056] Figure 3 It is a schematic diagram of an ultrasonic signal provided by an embodiment of the present application. Combining Figure 3 As shown, in order to reconstruct a two-dimensional optical signal through single-point detection of ultrasonic signals, the embodiment of the present application uses a water tank as an anisotropic acoustic cavity for reflecting photoacoustic signals. Specifically, a photoacoustic transducer absorbs the pulsed light beam carrying the information of the object to be measured and converts the corresponding optical signal into a first ultrasonic timing signal, so that the first ultrasonic timing signal can be reflected multiple times in the water tank. Then, through a single-pixel ultrasonic probe (ultrasonic transducer), a single acquisition is performed from the first ultrasonic timing signal reflected in the water tank, and an ultrasonic timing signal with a length of 2.4 microseconds is collected as the target ultrasonic timing signal corresponding to the pulsed light beam carrying the information of the object to be measured, and a corresponding electrical signal response value is output to the signal acquisition card.
[0057] S202: Based on the target ultrasonic timing signal, use the trained mapping model to reconstruct the optical pattern corresponding to the object to be measured and obtain a target image.
[0058] In practical applications, different images mapped by different ultrasonic timing signals are recorded in the trained mapping model. Since the delay characteristics generated by points at different positions on the object to be measured are different, the spatial position information of each optical point on the object to be measured can be effectively converted into a unique ultrasonic timing signal. The uniqueness of the ultrasonic timing signals corresponding to each point enables parallel detection. Therefore, the embodiment of the present application can use the trained mapping model to decode the superimposed signal (target ultrasonic timing signal) of the photoacoustic signals generated by each point to reconstruct the optical pattern corresponding to the object to be measured and obtain a target image. In addition, a single-pixel ultrasonic transducer is used to perform simultaneous single-point single detection on the ultrasonic timing signal excited by the optical signal, realizing single-pixel imaging with single acquisition.
[0059] In addition, since the methods for obtaining single-pixel images are different, the embodiment of the present application can illustrate a possible acquisition method.
[0060] In one case, S202: Based on the target ultrasonic timing signal, use the trained mapping model to reconstruct the optical pattern corresponding to the object to be measured and obtain a target image, specifically including:
[0061] Convert the target ultrasonic timing signal into a target digital signal through a signal acquisition card;
[0062] Based on the target digital signal, use the trained mapping model to reconstruct the optical pattern corresponding to the object to be measured, and obtain the target image.
[0063] In practical applications, based on the ultrasonic transducer, simultaneous single-point single-shot detection is performed to collect the target ultrasonic time-series signal with a length of 2.4 microseconds, and the electrical signal response value is output to the signal acquisition card. Then, the signal acquisition card converts the electrical signal response value into the corresponding target digital signal and sends it to the computer. The trained mapping model is used to decode the target digital signal corresponding to each point to reconstruct the optical pattern corresponding to the object to be measured, and obtain the corresponding target image, realizing single-pixel imaging with single-shot acquisition. Figure 4 This is an imaging effect diagram provided by an embodiment of the present application. Combining Figure 4 As shown, through the above microscopic device, combined with the trained mapping model, the paper with the letters "U", "S", "T", and "C" engraved on it is imaged, and its imaging effect has a certain resolution. In addition, fixing the paper with the letters "U", "S", "T", and "C" on the turntable and rotating the turntable can also obtain the target image, verifying that the method provided by the embodiment of the present application can perform fast dynamic imaging and provides a new tool for imaging moving objects.
[0064] In addition, since the methods of training the mapping model are different, an embodiment of the present application can illustrate in a possible training method.
[0065] In one case, the mapping model is trained by the following method:
[0066] Obtain the ultrasonic waveform of the training ultrasonic time-series signal corresponding to the optical image;
[0067] Based on the ultrasonic waveform and the optical image, train the U-Net model and obtain the trained mapping model.
[0068] In practical applications, during the model training stage, the object to be measured in the optical path generated by the microscopic device needs to be removed, and the computer is used to control the DMD to present different two-dimensional optical images. Since the information of each two-dimensional optical image is known, the U-Net model can be trained through each two-dimensional optical image and the ultrasonic waveform corresponding to each two-dimensional optical image, so as to learn the mapping relationship between the two and obtain the trained mapping model.
[0069] In addition, since the methods of obtaining the ultrasonic waveform are different, an embodiment of the present application can illustrate a possible obtaining method.
[0070] In one case, the obtaining the ultrasonic waveform of the training ultrasonic time-series signal corresponding to the optical image includes:
[0071] Convert the optical signals corresponding to the optical images in the training set into second ultrasonic time series signals;
[0072] Control the reflection of the second ultrasonic time series signal in an anisotropic acoustic cavity;
[0073] Through an ultrasonic transducer, perform a single acquisition on the second ultrasonic time series signal reflected in the acoustic cavity, and obtain the training ultrasonic time series signal corresponding to the optical field;
[0074] Convert the training ultrasonic time series signal into a digital signal through a signal acquisition card;
[0075] Determine the ultrasonic waveform of the training ultrasonic time series signal based on the data signal.
[0076] In practical applications, during the model training stage, a computer is used to control a digital microscope array to generate different two-dimensional optical images. The optical fields corresponding to these optical images are incident on a photoacoustic conversion system, absorbed by a light absorber, and converted into specific ultrasonic time series signals (i.e., convert the optical signals corresponding to the optical field into second ultrasonic time series signals). Then, control the second ultrasonic time series signal to be reflected in a water tank, and a single-pixel ultrasonic transducer simultaneously performs single-point single detection on the second ultrasonic time series signal excited by the two-dimensional optical signal, and obtains the training ultrasonic time series signal corresponding to each two-dimensional optical image. A digital acquisition card acquires these ultrasonic time series signals and converts them into digital signals, and then determines the ultrasonic waveform. Finally, the U-Net model is trained through each two-dimensional optical image and the ultrasonic waveform corresponding to each two-dimensional optical image, so as to learn the mapping relationship between the two, and obtain a trained mapping model.
[0077] In summary, the present application first performs a single acquisition on the target ultrasonic time series signal corresponding to the pulsed light beam carrying the information of the object to be measured. Then, based on the target ultrasonic time series signal, the trained mapping model is used to reconstruct the information of the object to be measured, and a single-pixel image is obtained. In this way, by using the photoacoustic effect, single-pixel imaging with single acquisition is realized through single-point single detection, thereby improving the imaging speed.
[0078] Figure 5 FIG. is a schematic structural diagram of a single-pixel imaging device with single acquisition provided by an embodiment of the present application. Combined with Figure 5 As shown, a single-pixel imaging device 500 with single acquisition provided by an embodiment of the present application includes:
[0079] An acquisition module 501, configured to perform a single acquisition on the target ultrasonic time series signal corresponding to the pulsed light beam carrying the information of the object to be measured;
[0080] A reconstruction module 502, configured to reconstruct the optical pattern corresponding to the object to be measured based on the target ultrasonic time series signal by using a trained mapping model, and obtain a target image.
[0081] As an implementation, for how to convert an optical signal into an ultrasonic signal, the single-pixel imaging device 500 for single-shot acquisition further includes: a first conversion module;
[0082] The first conversion module is configured to obtain a pulsed light beam carrying information of the object to be measured through a photoacoustic converter, and convert the optical signal corresponding to the pulsed light beam into a first ultrasonic time series signal.
[0083] As an implementation, for how to control the reflection of the first ultrasonic time series signal, the single-pixel imaging device 500 for single-shot acquisition further includes: a reflection module;
[0084] The reflection module is configured to control the reflection of the first ultrasonic time series signal in an anisotropic acoustic cavity.
[0085] As an implementation, for how to obtain the first ultrasonic time series signal, the acquisition module 501 is specifically configured to:
[0086] Perform single-shot acquisition on the first ultrasonic time series signal reflected in the acoustic cavity through an ultrasonic converter, and obtain a target ultrasonic time series signal corresponding to the pulsed light beam carrying information of the object to be measured.
[0087] Wherein, the length of the target ultrasonic time series signal is 2.4 microseconds.
[0088] As an implementation, for how to obtain a single-pixel image, the reconstruction module 502 is specifically configured to:
[0089] Convert the target ultrasonic time series signal into a target digital signal through a signal acquisition card;
[0090] Based on the target digital signal, reconstruct the optical pattern corresponding to the object to be measured by using a trained mapping model, and obtain a target image.
[0091] As an implementation, for how to train the training mapping model, the single-pixel imaging device 500 for single-shot acquisition further includes: an acquisition module and a training module;
[0092] The acquisition module is configured to obtain the ultrasonic waveform of the training ultrasonic time series signal corresponding to the optical image;
[0093] The training module is configured to train a U-Net model based on the ultrasonic waveform and the optical image, and obtain a trained mapping model.
[0094] As an implementation manner, for how to obtain the ultrasonic waveform of the training ultrasonic time series signal, the above-mentioned obtaining module is specifically used for:
[0095] Obtain the optical field corresponding to the optical image through a photoacoustic converter, and convert the optical signal corresponding to the optical field into a second ultrasonic time series signal;
[0096] Control the second ultrasonic time series signal to be reflected in the anisotropic acoustic cavity;
[0097] Through an ultrasonic converter, perform a single acquisition on the second ultrasonic time series signal reflected in the acoustic cavity, and obtain the training ultrasonic time series signal corresponding to the optical field;
[0098] Convert the training ultrasonic time series signal into a digital signal through a signal acquisition card;
[0099] Determine the ultrasonic waveform of the training ultrasonic time series signal based on the data signal.
[0100] In summary, the present application first performs a single acquisition on the target ultrasonic time series signal corresponding to the pulsed light beam carrying the information of the object to be measured. Then, based on the target ultrasonic time series signal, the information of the object to be measured is reconstructed by using the trained mapping model, and a single-pixel image is obtained. In this way, by utilizing the photoacoustic effect, single-pixel imaging with single acquisition is realized through single-point single detection, thereby improving the imaging speed.
[0101] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A single-pixel imaging method for single acquisition, characterized in that: The method comprises: Single acquisition of the target ultrasonic timing signal corresponding to the pulse beam carrying the information of the object to be measured; Based on the target ultrasonic time series signal, the optical pattern corresponding to the object to be measured is reconstructed using the trained mapping model to obtain a target image.
2. The method according to claim 1, characterized in that Before the single acquisition of the target ultrasonic time sequence signal corresponding to the pulse light beam carrying the information of the object to be measured, the method further includes: A pulse light beam carrying information of the object to be measured is obtained through a photoacoustic converter, and an optical signal corresponding to the pulse light beam is converted into a first ultrasonic timing signal.
3. The method according to claim 2, characterized in that The method further comprises: controlling the first ultrasonic time-series signal to be reflected in an anisotropic acoustic cavity; The single acquisition of the target ultrasonic time sequence signal corresponding to the pulse light beam carrying the information of the object to be measured includes: The first ultrasonic time-series signal reflected in the acoustic cavity is collected once by an ultrasonic converter, and a target ultrasonic time-series signal corresponding to a pulse light beam carrying information of the object to be measured is obtained.
4. The method according to claim 1, characterized in that: The length of the target ultrasonic timing signal is 2.4 microseconds.
5. The method according to claim 1, characterized in that The method of reconstructing the optical pattern corresponding to the object to be measured by using a trained mapping model based on the target ultrasonic time series signal and obtaining a target image includes: Converting the target ultrasonic timing signal into a target digital signal through a signal acquisition card; Based on the target digital signal, the optical pattern corresponding to the object to be measured is reconstructed using the trained mapping model to obtain a target image.
6. The method according to claim 1, characterized in that The mapping model is trained by the following method: Acquire the ultrasonic waveform of the training ultrasonic time-series signal corresponding to the optical image; A U-Net model is trained based on the ultrasonic waveform and the optical image, and a trained mapping model is obtained.
7. The method according to claim 6, characterized in that The step of acquiring the ultrasonic waveform of the training ultrasonic time-series signal corresponding to the optical image comprises: Converting the optical signal corresponding to the optical image in the training set into a second ultrasonic time series signal; controlling the second ultrasonic time-series signal to be reflected in an anisotropic acoustic cavity; The second ultrasonic time-series signal reflected in the acoustic cavity is collected once by an ultrasonic converter, and a training ultrasonic time-series signal corresponding to the light field is obtained; Converting the training ultrasonic time-series signal into a digital signal through a signal acquisition card; The ultrasonic waveform of the training ultrasonic timing signal is determined based on the data signal.
8. A single-pixel imaging device for single acquisition, characterized in that: include: An acquisition module, used for single acquisition of a target ultrasonic timing signal corresponding to a pulse beam carrying information of the object to be measured; A reconstruction module is used to reconstruct the optical pattern corresponding to the object to be measured based on the target ultrasonic time series signal using a trained mapping model to obtain a target image.