Single-pixel imaging system, method, device and medium for quasi-periodic moving objects

Abstract

The application discloses a kind of quasi-periodic motion object's single-pixel imaging system, method, device and medium, imaging system includes probe light source, first single-pixel detector, spatial light modulator, illumination light source, imaging lens, second single-pixel detector, multi-channel signal synchronous acquisition card and controller, light emitted by probe light source reaches first single-pixel detector after target object, light emitted by illumination light source reaches second single-pixel detector in turn after spatial light modulator, imaging lens and target object, or light emitted by illumination light source reaches second single-pixel detector in turn after target object, imaging lens and spatial light modulator, controller is used to control spatial light modulator, multi-channel signal synchronous acquisition card and according to the image of the image of target object reconstructed according to the signal collected.The embodiment of the application can improve imaging quality and reduce target object movement speed is limited by spatial light modulator modulation rate, can be widely applied in optical imaging technical field.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a single-pixel imaging system, method, apparatus and medium for quasi-periodic moving objects. Background Technology

[0002] Imaging high-speed moving objects has important applications in many fields. However, traditional optical imaging methods have always posed a significant challenge to imaging high-speed moving objects due to motion blur. Although high-speed cameras capable of capturing millions of frames per second have been developed for imaging high-speed moving objects, many limitations remain, such as the requirement for high-brightness illumination, the inability to continuously capture images for extended periods, and high equipment costs.

[0003] Single-pixel imaging utilizes a spatial light modulator to spatially modulate the target light field (active or passive modulation), while a single-pixel detector acquires the signal once for each modulation. Finally, the image of the target object is reconstructed using the temporal measurements. Compared to traditional optical imaging, single-pixel imaging has significant advantages in non-visible light imaging, low-light imaging, and high dynamic range imaging.

[0004] In related schemes, for imaging high-speed periodically moving objects, the motion period of the object is assumed to be stable during single-pixel imaging. When the object's motion period fluctuates, i.e., when the object is quasi-periodic, the imaging quality of this scheme may be significantly reduced; the greater the fluctuation in the motion period, the more severe the degradation in imaging quality. In another related scheme, for rotating objects driven by stepper motors, the pulse signal from the stepper motor's rotation triggers a spatial light modulator to modulate the target light field. However, the maximum rotational speed of the moving object that can be imaged is limited by the modulation rate of the spatial light modulator. Summary of the Invention

[0005] In view of this, the purpose of the embodiments of the present invention is to provide a single-pixel imaging system, method, device and medium for quasi-periodic moving objects, which can reduce the impact of periodic fluctuations on imaging quality, improve imaging quality and solve the problem that the maximum speed of the target object's quasi-periodic motion is limited by the modulation rate of the spatial light modulator.

[0006] On one hand, embodiments of the present invention provide a single-pixel imaging system for a quasi-periodic moving object, including a detection light source (1), a first single-pixel detector (2), a spatial light modulator (3), an illumination light source (4), an imaging lens (5), a second single-pixel detector (6), a multi-channel signal synchronous acquisition card (7), and a controller (8). The light emitted by the detection light source (1) passes through the target object and reaches the first single-pixel detector (2). The light emitted by the illumination light source (4) passes sequentially through the spatial light modulator (3), the imaging lens (5), and the target object before reaching the second single-pixel detector (6). Alternatively, the light emitted by the illumination light source (4) passes sequentially through the target object, the imaging lens (5), and the spatial light modulator (3) before reaching the second single-pixel detector (6).

[0007] The multi-channel signal synchronous acquisition card (7) is used to synchronously acquire signals from the first single-pixel detector (2), the spatial light modulator (3), and the second single-pixel detector (6).

[0008] The controller (8) is used to control the spatial light modulator (3) to modulate the light field, control the multi-channel signal synchronous acquisition card (7) to synchronously acquire signals, and reconstruct the image of the target object based on the acquired signals.

[0009] Optionally, the detection light source (1) and the illumination light source (4) have different wavelengths or polarization states; the first single-pixel detector (2) and the second single-pixel detector (6) are provided with color filters of corresponding wavelengths or polarizers of corresponding polarization states.

[0010] Optionally, both the first single-pixel detector (2) and the second single-pixel detector (6) include at least one condenser lens and at least one single-pixel photodetector.

[0011] Optionally, the detection light source (1) includes multiple sub-light sources, the first single-pixel detector (2) includes multiple sub-detectors, one sub-light source corresponds to one sub-detector, and the signal of each sub-detector is synchronously acquired by a multi-channel signal synchronous acquisition card (7).

[0012] On the other hand, embodiments of the present invention provide a single-pixel imaging method for a quasi-periodic moving object, comprising:

[0013] Turn on the detection light source (1) to emit a beam to the target object, control the multi-channel signal synchronous acquisition card (7) to acquire the zeroth detection value sequence of the first single pixel detector (2), and determine the modulation frequency of the spatial light modulator (3) based on the zeroth detection value sequence;

[0014] Generate modulation patterns with different spatial distributions, use the modulation patterns and the modulation frequency to control the spatial light modulator (3) to modulate the light field, control the multi-channel signal synchronous acquisition card (7) to acquire the first detection value sequence of the first single pixel detector (2), the synchronous output signal of the spatial light modulator (3) when switching the modulation pattern, and the second detection value sequence of the second single pixel detector (6).

[0015] The image of the target object is reconstructed based on the first detection value sequence, the second detection value sequence, and the synchronous output signal when the modulation pattern is switched.

[0016] Optionally, determining the modulation frequency of the spatial light modulator (3) based on the zeroth probe value sequence specifically includes:

[0017] The maximum period of the periodic motion of the target object is determined based on the periodic characteristics of the zeroth detection value sequence;

[0018] The modulation frequency of the spatial light modulator (3) is determined based on the maximum period.

[0019] Optionally, reconstructing the image of the target object based on the first detection value sequence, the second detection value sequence, and the synchronous output signal during the switching modulation pattern specifically includes:

[0020] Based on the periodicity of the first detection value sequence, the sampling points of the second detection value sequence are segmented according to the motion cycle of the target object to obtain the number of sampling points in each cycle and the starting sampling point number of each cycle.

[0021] Based on the number of sampling points, the sequence number of the starting sampling point, and the change characteristics within the period of the first detection value sequence, the phase value of the target object's position corresponding to each sampling point is determined, and the phase values ​​corresponding to the sampling points of the second detection value sequence are combined to form a first phase value sequence.

[0022] For a phase value, in the first phase value sequence, the sampling point number of the phase value in different periods is determined, and combined with the synchronous output signal of the spatial light modulator (3) when switching patterns, the second detection value corresponding to all modulation patterns under the phase value is determined;

[0023] The image of the target object is reconstructed based on the second detection value corresponding to all modulation patterns at the stated phase value.

[0024] Optionally, the second detection value corresponding to all modulation patterns under the phase value is determined by the following method:

[0025] If the phase value does not exist in a certain period in the first phase value sequence, the second detection value sequence is interpolated according to the interpolation method to determine the second detection value corresponding to all modulation patterns under the phase value.

[0026] On the other hand, embodiments of the present invention provide a single-pixel imaging device for a quasi-periodic moving object, comprising:

[0027] At least one processor;

[0028] At least one memory for storing at least one program;

[0029] When the at least one program is executed by the at least one processor, the at least one processor implements the single-pixel imaging method described above.

[0030] On the other hand, embodiments of the present invention provide a computer-readable storage medium storing a processor-executable program, which, when executed by a processor, is used to perform the above-described single-pixel imaging method.

[0031] Implementing the embodiments of the present invention has the following beneficial effects: A single-pixel imaging system for quasi-periodic moving objects includes a detection light source, a first single-pixel detector, a spatial light modulator, an illumination light source, an imaging lens, a second single-pixel detector, a multi-channel signal synchronous acquisition card, and a controller. Light emitted from the detection light source passes through the target object and reaches the first single-pixel detector. Light emitted from the illumination light source sequentially passes through the spatial light modulator, the imaging lens, and the target object before reaching the second single-pixel detector; or light emitted from the illumination light source sequentially passes through the target object, the imaging lens, and the spatial light modulator before reaching the second single-pixel detector. The multi-channel signal synchronous acquisition card is used to synchronously acquire signals from the first single-pixel detector, the spatial light modulator, and the second single-pixel detector. The controller is used to control the spatial light modulator to modulate the light field, control the multi-channel signal synchronous acquisition card to synchronously acquire signals, and reconstruct the image of the target object based on the acquired signals. For quasi-periodic moving objects, through... The detection light source monitors the motion period of the target object by passing through the zero-detection value sequence of the first single-pixel detector. Based on the zero-detection value sequence of the first single-pixel detector, the modulation frequency of the spatial light modulator is determined. The spatial light modulator is controlled to modulate the light field according to the modulation patterns and modulation frequencies with different spatial distributions. The second detection value sequence of the second single-pixel detector, the first detection value sequence of the first single-pixel detector, and the synchronous output signal when the spatial light modulator switches modulation patterns are collected. The image is reconstructed based on the signals corresponding to all modulation patterns under the same phase value in the second detection value sequence, thereby reducing the impact of periodic fluctuations on imaging quality and improving imaging quality. In addition, by controlling the spatial light modulator together with the modulation patterns and modulation frequencies with different spatial distributions, it is only required that the modulation frequency of the spatial light modulator is less than the reciprocal of the maximum motion period of the target object, thereby solving the problem that the maximum speed of the quasi-periodic motion of the target object is limited by the modulation rate of the spatial light modulator. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a single-pixel imaging system for a quasi-periodic moving object provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of another single-pixel imaging system for quasi-periodic moving objects provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic flowchart of a single-pixel imaging method for a quasi-periodic moving object provided in an embodiment of the present invention;

[0035] Figure 4 This invention provides a four-binarized Fourier transform basis pattern corresponding to a spatial frequency in a Fourier spectrum.

[0036] Figure 5This is a periodic variation diagram of the motion of a target object determined based on the zeroth detection value sequence, provided by an embodiment of the present invention.

[0037] Figure 6 This is a data distribution diagram of sampling points of a multi-channel signal synchronous acquisition card provided in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of a single-pixel imaging result of a quasi-periodic moving object provided in an embodiment of the present invention;

[0039] Figure 8 This is a structural block diagram of a single-pixel imaging device for a quasi-periodic moving object provided in an embodiment of the present invention. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0041] This invention provides a single-pixel imaging system for a quasi-periodic moving object, comprising a detection light source (1), a first single-pixel detector (2), a spatial light modulator (3), an illumination light source (4), an imaging lens (5), a second single-pixel detector (6), a multi-channel signal synchronous acquisition card (7), and a controller (8). Light emitted from the detection light source (1) passes through the target object and reaches the first single-pixel detector (2). Light emitted from the illumination light source (4) passes sequentially through the spatial light modulator (3), the imaging lens (5), and the target object before reaching the second single-pixel detector (6). Alternatively, light emitted from the illumination light source (4) passes sequentially through the target object, the imaging lens (5), and the spatial light modulator (3) before reaching the second single-pixel detector (6).

[0042] A multi-channel signal synchronous acquisition card (7) is used to synchronously acquire signals from the first single-pixel detector (2), the spatial light modulator (3), and the second single-pixel detector (6).

[0043] The controller (8) is used to control the spatial light modulator (3) to modulate the light field, control the multi-channel signal synchronous acquisition card (7) to synchronously acquire signals, and reconstruct the image of the target object based on the acquired signals.

[0044] Specifically, the controller (8) includes, but is not limited to, computer devices or wearable devices with processors, such as desktop computers, laptops or fitness trackers.

[0045] It should be noted that the detection light source (1) and the illumination light source (4) are determined according to the actual application, and this embodiment does not impose specific restrictions.

[0046] like Figure 1 As shown, in one specific embodiment, the imaging system includes: a detection light source 1, a first single-pixel detector 2, a spatial light modulator 3, an illumination light source 4, an imaging lens 5, a second single-pixel detector 6, a multi-channel signal synchronous acquisition card 7, a controller 8, and a target object 9. The detection light source 1 is a helium-neon laser with a wavelength of 632.8 nm and a power of 3 mW. The first single-pixel detector 2 is a silicon photodetector with a bandwidth of 1.4 MHz. The spatial light modulator 3 is a digital micromirror device with a resolution of 1024×768 and a maximum modulation frequency of 22727 Hz. The illumination light source 4 is a white LED with a power of 10 watts. The imaging lens 5 is a lens with a focal length of 100 mm. The second single-pixel detector 6 includes a condenser lens 61 with a focal length of 60 mm and a silicon photodetector 62 with a bandwidth of 90 kHz. The multi-channel signal synchronous acquisition card 7 has a maximum sampling rate of 2×10⁻⁶. 6 The system uses a signal acquisition card with a Hz frequency and an analog input resolution of 16 bits. The target object 9 is a fan with 7 blades that rotates at approximately 14,400 revolutions per minute. A light beam emitted from the detection light source 1 illuminates the target object 9, and the light signal from the target object 9 is detected by the first single-pixel detector 2. A light beam emitted from the illumination light source 4 illuminates the spatial light modulator 3, and after modulation, the beam is imaged onto the target object 9 by the imaging lens 5. The light signal reflected by the target object 9 is detected by the second single-pixel detector 6. The output signal terminals of the first single-pixel detector 2, the spatial light modulator 3, and the second single-pixel detector 6 are respectively connected to the three different channel signal input terminals of the multi-channel signal synchronous acquisition card 7 for synchronous signal acquisition. The controller 8 is connected to both the spatial light modulator 3 and the multi-channel signal synchronous acquisition card 7, and is used to control the spatial light modulator 3 to modulate the light field and control the multi-channel signal synchronous acquisition card 7 to synchronously acquire signals. It is also used to store and analyze the acquired signal data and calculate and reconstruct the image of the target object 9.

[0047] like Figure 2As shown, in one specific embodiment, the imaging system includes: a detection light source 1, a first single-pixel detector 2, a spatial light modulator 3, an illumination light source 4, an imaging lens 5, a second single-pixel detector 6, a multi-channel signal synchronous acquisition card 7, a controller 8, and a target object 9. The detection light source 1 is a helium-neon laser with a wavelength of 632.8 nm and a power of 3 mW. The first single-pixel detector 2 is a silicon photodetector with a bandwidth of 1.4 MHz. The spatial light modulator 3 is a digital micromirror device with a resolution of 1024×768 and a maximum modulation frequency of 22727 Hz. The illumination light source 4 is a white LED with a power of 10 watts. The imaging lens 5 is a lens with a focal length of 100 mm. The second single-pixel detector 6 includes a condenser lens 61 with a focal length of 60 mm and a silicon photodetector 62 with a bandwidth of 90 kHz. The multi-channel signal synchronous acquisition card 7 has a maximum sampling rate of 2×10⁻⁶. 6 The system uses a signal acquisition card with a Hz frequency and an analog input resolution of 16 bits. The target object 9 is a fan with 7 blades that rotates at approximately 14,400 revolutions per minute. A light beam emitted from the detection light source 1 illuminates the target object 9, and the light signal from the target object is detected by the first single-pixel detector 2. A light beam emitted from the illumination light source 4 illuminates the target object 9, and the imaging lens 5 images the target object 9 onto the modulation surface of the spatial light modulator. The modulated light signal is detected by the second single-pixel detector 6. The output signal terminals of the first single-pixel detector 2, the spatial light modulator 3, and the second single-pixel detector 6 are respectively connected to the three different channel signal input terminals of the multi-channel signal synchronous acquisition card 7 for synchronous signal acquisition. The controller 8 is connected to both the spatial light modulator 3 and the multi-channel signal synchronous acquisition card 7, and is used to control the spatial light modulator 3 to modulate the light field and the multi-channel signal synchronous acquisition card 7 to synchronously acquire the signal. It is also used to store and analyze the acquired signal data and calculate and reconstruct the image of the target object 9.

[0048] Optionally, the detection light source (1) and the illumination light source (4) have different wavelengths or polarization states; the first single-pixel detector (2) and the second single-pixel detector (6) are provided with color filters of corresponding wavelengths or polarizers of corresponding polarization states.

[0049] The detection light source (1) and the illumination light source (4) have different wavelengths or polarization states, which reduces the interference between the two beams and improves the accuracy of signal acquisition and imaging. The beam inlets of the first single-pixel detector (2) and the second single-pixel detector (6) are equipped with color filters of corresponding wavelengths or polarizers of corresponding polarization states to filter out stray light and further improve the accuracy of signal acquisition and imaging.

[0050] Optionally, both the first single-pixel detector (2) and the second single-pixel detector (6) include at least one condenser lens and at least one single-pixel photodetector.

[0051] The condenser lens and single-pixel photodetector contained in the first single-pixel detector (2) and the second single-pixel detector (6) are paired with each other. The specific number of condenser lenses and single-pixel photodetectors is determined according to the actual application, and no specific limitation is made in this embodiment.

[0052] Optionally, the detection light source (1) includes multiple sub-light sources, the first single-pixel detector (2) includes multiple sub-detectors, one sub-light source corresponds to one sub-detector, and the signal of each sub-detector is synchronously acquired by the multi-channel signal synchronous acquisition card (7).

[0053] The number of sub-light sources included in the detection light source (1) is determined according to the actual application, and this embodiment does not impose a specific limitation. Multiple sub-light sources can be used to further improve the accuracy of object motion position monitoring.

[0054] See Figure 3 This invention provides a single-pixel imaging method for quasi-periodic moving objects, comprising:

[0055] S100, turn on the detection light source to emit a beam to the target object, control the multi-channel signal synchronous acquisition card (7) to acquire the zeroth detection value sequence of the first single pixel detector (2), and determine the modulation frequency of the spatial light modulator (3) based on the zeroth detection value sequence.

[0056] Specifically, the detection light source (1) is turned on to emit a beam of light to the target object (9), and the signal sampling frequency f of the multi-channel signal synchronous acquisition card (7) is set. d The multi-channel signal synchronous acquisition card (7) acquires the zeroth detection value sequence of the first single-pixel detector (2) and determines the modulation frequency of the spatial light modulator (3) based on the periodic characteristics of the zeroth detection value sequence.

[0057] Optionally, the modulation frequency of the spatial light modulator is determined based on the detected value, specifically including:

[0058] S110. Determine the maximum period of the periodic motion of the target object based on the periodic characteristics of the zeroth detection value sequence;

[0059] S120. Determine the modulation frequency of the spatial light modulator (3) based on the maximum period.

[0060] Specifically, the maximum period T of the periodic motion of the target object (9) is estimated based on the periodic characteristics of the zeroth detection value sequence of the first single-pixel detector (2). max Set the modulation frequency f of the spatial light modulator (3) m f d Much greater than f m , f d f m T maxIt is a positive real number.

[0061] S200, Generate modulation patterns with different spatial distributions, and use the modulation patterns and modulation frequencies to control the spatial light modulator (3) to modulate the light field, and control the multi-channel signal synchronous acquisition card (7) to acquire the first detection value sequence of the first single-pixel detector (2), the synchronous output signal of the spatial light modulator (3) when switching modulation patterns, and the second detection value sequence of the second single-pixel detector (6).

[0062] The controller (8) pre-generates N spatial light modulators (3) with different spatial distributions according to the single-pixel imaging algorithm, and the modulation pattern P is... n n = 1, 2, ..., N, where n is a positive integer. The detection light source (1) emits a light beam to the target object (9), and the first single-pixel detector (2) detects the light signal from the target object (9); the controller (8) controls the multi-channel signal synchronous acquisition card (7) to operate at a preset sampling frequency f. d The detection values ​​of the first single-pixel detector (2) are acquired synchronously. Spatial light modulator (3) switches the output signal of the modulation pattern The detection value of the second single-pixel detector (6) Where, k c =0,1,2,…,K c , indicating the sampling point number of the multi-channel signal synchronous acquisition card (7), k c The integer is positive; at the same time, the computer (8) controls the spatial light modulator (3) to generate N pre-generated modulation patterns P n The light is sequentially loaded into the spatial light modulator (3) and modulated at a preset rate f. m Modulate the light field.

[0063] According to the output signal of the spatial light modulator (3) In the characteristic of switching modulation patterns, the sequence number of the starting sampling point of the first modulation pattern is set to k=0, the signal sampling sequence number of the multi-channel signal synchronous acquisition card (7) is reordered, and the detection value of the output signal of the spatial light modulator (3) by the multi-channel signal synchronous acquisition card (7) is expressed as D. m (t k The detection value of the first single-pixel detector (2) is represented as D1(t). k (i.e., the first detection value sequence), the detection value of the second single-pixel detector (6) is represented as D2(t) k (i.e., the second probe value sequence), where, Where k = 0, ±1, ±2, ..., ±K, k is an integer; all sampling point indices are segmented according to each modulation pattern to obtain the set K of sampling point indices corresponding to the nth modulation pattern. m (n).

[0064] S300: Reconstruct an image of the target object based on the first detection value sequence, the second detection value sequence, and the synchronous output signal when switching the modulation pattern.

[0065] Specifically, the synchronously acquired data is aligned with the modulation period of the spatial light modulator (3) and the motion period of the object. The detection values ​​detected by the second single-pixel detector (6) corresponding to all modulation patterns when the moving object is at the same motion position phase value are extracted, and the image is reconstructed using the single-pixel reconstruction algorithm.

[0066] Optionally, reconstructing an image of the target object based on the first detection value sequence, the second detection value sequence, and the synchronous output signal during modulation pattern switching specifically includes:

[0067] S310. Based on the periodicity of the first detection value sequence, the sampling points of the second detection value sequence are segmented according to the target object's motion cycle to obtain the number of sampling points in each cycle and the starting sampling point number of each cycle.

[0068] Specifically, based on the spatial distribution characteristics of the light reflectance or transmittance of the target object (9) and the first detection value D1(t) of the first single-pixel detector (2), k The correspondence between the periodic features of the target object (9) and the second detection value D2(t) of the second single-pixel detector (6) is determined according to the motion period of the target object (9). k The sampling points of ) are segmented to obtain D2(t) k The number of sampling points S in the j-th period j and the sequence number k of the starting sampling point of this period 1 (j), where j represents the sequence number of the motion cycle, j = 1, 2, ..., J; S j J is a positive integer, k 1 (j) is an integer.

[0069] S320. Based on the number of sampling points, the sequence number of the starting sampling point, and the change characteristics within the period of the first detection value sequence, determine the phase value of the target object's position corresponding to each sampling point, and form a first phase value sequence by combining the phase values ​​corresponding to the sampling points of the second detection value sequence.

[0070] Specifically, based on the detected value D2(t) k The number of sampling points S in the j-th period j and the sequence number k of the starting sampling point 1 (j), determine the phase value of the target object (9) at the motion position corresponding to each sampling point in the j-th motion cycle, that is, the first phase value sequence. k 1 (j)≤k<k 1 (j)+S j;

[0071] Alternatively, based on the spatial distribution characteristics of the light reflectance or transmittance of the target object (9) and the detection value D1(t) of the first single-pixel detector (2), k The correspondence between the signal characteristics of ) and the detection value D2(t) in each motion cycle. k The sampling points are divided into L segments, of which Let l be the number of sampling points in the l-th segment within the j-th motion cycle. The phase value of the l-th segment is determined based on the morphological characteristics of the target object (9). l = 1, 2, ..., L, L ≥ 2, L is a positive integer; determine the phase value of the target object (9) at the motion position corresponding to each sampling point in the j-th motion cycle, that is, the first phase value sequence.

[0072]

[0073] S330. For a phase value, in the first phase value sequence, determine the sampling point number of the phase value in different periods, and combine it with the synchronous output signal of the spatial light modulator (3) when switching patterns to determine the second detection value corresponding to all modulation patterns under the phase value.

[0074] Specifically, step S330 may include steps S331 and S332.

[0075] S331, Based on the number of sampling points S in different periods j The number of cycles J is specified. in,

[0076] Alternatively, based on the phase value of the target object (9) at the motion position corresponding to each sampling point within the j-th motion cycle. Specify i = 1, 2, ..., S j k = i + k 1 (j)-1;

[0077] S332, Regarding the phase value Determine the sampling point number of this phase value within different periods. The set K of sampling point indices corresponding to the nth modulation pattern m In (n), filter those that meet the conditions. The sampling points are used to obtain the phase value. The sampling point corresponding to the nth modulation pattern Determine the phase value The detection values ​​of the second single-pixel detector (6) corresponding to the N modulation patterns respectively n = 1, 2, ..., N.

[0078] Optionally, the second detection value corresponding to all modulation patterns under the phase value is determined by the following method: if the phase value does not exist in a certain period in the first phase value sequence, the second detection value sequence is interpolated according to the interpolation method to determine the second detection value corresponding to all modulation patterns under the phase value.

[0079] Specifically, since the signals acquired by the multi-channel signal synchronous acquisition card (7) are discrete signals, when a signal that satisfies the condition cannot be found in the j-th period... When selecting sampling points, it is necessary to find those that satisfy... Using several sampling points near the second single-pixel detector (6), the detection value is interpolated using interpolation, so that the phase value of the motion position of the interpolated detection value is equal to the phase value of the second single-pixel detector (6).

[0080] S340. Reconstruct an image of the target object based on the second detection value corresponding to all modulation patterns at the said phase value.

[0081] Specifically, using phase values The detection values ​​of the next N second single-pixel detectors (6) n = 1, 2, ..., N, the phase is reconstructed using a single-pixel reconstruction algorithm. Image of the target object (9) below

[0082] In one specific embodiment, the process of a single-pixel imaging method for a quasi-periodic moving object is as follows:

[0083] S1. Based on the principle of four-step phase-shift Fourier single-pixel imaging, the imaging resolution is set to 256 pixels × 256 pixels and the Fourier spectrum sampling rate is 60%. Controller 8 pre-generates 78,642 spatial light modulator modulation patterns P with different spatial distributions according to the single-pixel imaging algorithm. n Let n = 1, 2, ..., 78642, where n is a positive integer. Each modulation pattern is upsampled to 512 pixels × 512 pixels using bicubic interpolation, and then converted into a binarized pattern that can be displayed by digital micromirror devices using a dithering algorithm. Figure 4 The diagram shows four binarized Fourier transform basis patterns corresponding to one spatial frequency of the Fourier spectrum.

[0084] Turn on the detection light source 1 to emit a beam of light onto the target object 9, and set the signal sampling frequency f of the multi-channel signal synchronous acquisition card 7. d =2×10 6 Hz, multi-channel signal synchronous acquisition card 7 acquires the zeroth detection value sequence D0(t) of the first single-pixel detector 2 within 5 seconds.q ), Where q = 0, 1, 2, ..., Q represents the sampling point number of the multi-channel signal synchronous acquisition card 7, and q is a positive integer. When the laser light emitted by the detection light source 1 is blocked by the fan blades, D0(t) q () represents a low voltage signal. When the light emitted by the detection light source 1 passes through the gap between the fan blades, D0(t) q The signal is a high voltage signal, and within one motion cycle of the target object 9, it will undergo seven changes from a low voltage signal to a high voltage signal; within different cycles of the target object 9, corresponding to the same blade, during the signal change process from low voltage to high voltage, based on the collected detection value D1(t)... q The sampling interval Δq between sampling points whose voltage values ​​reach half the size of a high-voltage signal and the signal sampling frequency f of the multi-channel signal synchronous acquisition card. d Calculate the motion period of target object 9 like Figure 5 As shown, the motion period of target object 9 fluctuates within a certain range; calculate the maximum motion period T of target object 9. max = 4.179ms and average period And set the modulation rate f of the spatial light modulator 3. m =119.99Hz, this setting meets the requirements.

[0085] S2. The detection light source 1 emits a light beam to the target object 9, and the first single-pixel detector 2 detects the light signal from the target object 9; the controller 8 controls the multi-channel signal synchronous acquisition card 7 to operate at a preset sampling frequency f. d The detection values ​​of the first single-pixel detector 2 are acquired synchronously. The spatial light modulator 3 switches the synchronous output signal of the modulation pattern. The detection value of the second single-pixel detector 6 Where, k c =0,1,2,…,K c , indicating the sampling point number of the multi-channel signal synchronous acquisition card 7, k c The integer is positive; simultaneously, controller 8 controls spatial light modulator 3 to apply 78,642 pre-generated modulation patterns P with different spatial distributions. n The light is sequentially loaded into the spatial light modulator 3, according to the preset modulation rate f. m Modulate the light field; Figure 6 Partial display and The synchronous sampling signal includes 50,000 sampling points per channel.

[0086] S3, based on the output signal of spatial light modulator 3 The characteristic of switching from a low-voltage signal to a high-voltage signal when changing modulation patterns is that the starting sampling point of the first modulation pattern is set to k=0. The signal sampling sequence of the multi-channel signal synchronous acquisition card 7 is reordered, and the detection value of the output signal of the spatial light modulator 3 by the multi-channel signal synchronous acquisition card 7 is represented as D. m (t k The detection value of the first single-pixel detector 2 is represented as D1(t). k (i.e., the first detection value sequence), the detection value of the second single-pixel detector 6 is represented as D2(t) k (i.e., the second probe value sequence), where, Where k = 0, ±1, ±2, ..., ±K, k is an integer; all sampling point indices are segmented according to each modulation pattern to obtain the set K of sampling point indices corresponding to the nth modulation pattern. m (n).

[0087] S4. Based on the characteristic of the target object 9 having 7 blades and the detection value D1(t) of the first single-pixel detector 2 k The characteristics of seven voltage changes from low to high voltage generated within one motion cycle of target object 9, and the corresponding relationship between them, are analyzed according to the motion cycle of target object 9, and the detected value D2(t) is analyzed. k The sampling points of ) are segmented to obtain D2(t) k The number of sampling points S in the j-th period j and the sequence number k of the starting sampling point of this period 1 (j), where j represents the sequence number of the motion cycle, j = 1, 2, ..., J, S j J is a positive integer, k 1 (j) is an integer.

[0088] S5, using the detection value D1(t) of the first single-pixel detector 2 k In a series of signal changes from low to high voltage within one cycle, the sampling point where the voltage value reaches half the size of the high voltage signal is used as the dividing point. The detected value D2(t) within each motion cycle is then used as the dividing point. k The sampling points are segmented. There are a total of L segments (L=7), of which Let l be the number of sampling points in the l-th segment within the j-th motion cycle. The phase value of the l-th segment is determined based on the shape characteristics of the target object 9. l = 1, 2, ..., L; determine the phase value of the target object 9 at each sampling point within the j-th motion cycle, i.e., the first phase value sequence.

[0089]

[0090] S6, Order The phase value of the target object 9 at the motion position corresponding to each sampling point within the first motion cycle in step S5. i=1, 2,..., S1, S1=8323, k=i+k 1 (1)-1.

[0091] S7, for phase is Determine the sampling point number of this phase value within different periods. The set K of sampling point indices corresponding to the nth modulation pattern m In (n), filter those that meet the conditions. The sampling points are used to obtain the phase value. The sampling point corresponding to the nth modulation pattern Determine the phase value The detection values ​​of the second single-pixel detector (6) corresponding to the 78,642 modulation patterns are as follows. n = 1, 2, ..., 78642.

[0092] Since the signals acquired by the multi-channel signal synchronous acquisition card 7 are discrete signals, when a signal that satisfies the condition cannot be found within the j-th period... When selecting sampling points, it is necessary to find those that satisfy... Using several sampling points near the first pixel and combining the nearest neighbor interpolation method, the detected value of the second single-pixel detector 6 is interpolated to obtain the interpolated detected value. The phase value of the position of motion is equal to

[0093] S8, using phase value The detection values ​​of the second single-pixel detector 6 are 78,642. n = 1, 2, ..., 78642, the phase is reconstructed using the single-pixel reconstruction algorithm. Image of target object 9 below Figure 7 It shows the results of imaging the target object 9, where, Figure 7 (a) Figure 7 (b) Figure 7 (c) Figure 7 (d) Figure 7 (e) and Figure 7 (f) are the phases of the target object 9's motion position. 0, and Reconstructed images, different phases The images record the dynamic changes of an object during rotation.

[0094] In another specific embodiment, the process of a single-pixel imaging method for a quasi-periodic moving object is as follows:

[0095] S11. Based on the principle of four-step phase-shift Fourier single-pixel imaging, the imaging resolution is set to 256 pixels × 256 pixels and the Fourier spectrum sampling rate is 60%. Controller 8 pre-generates 78,642 spatial light modulator modulation patterns P with different spatial distributions according to the single-pixel imaging algorithm. n n = 1, 2, ..., 78642, where n is a positive integer. Each modulation pattern is upsampled to 512 pixels × 512 pixels using bicubic interpolation, and then converted into a binary pattern that can be displayed by a digital micromirror device using a dithering algorithm.

[0096] Turn on the detection light source 1 to emit a beam of light onto the target object 9, and set the signal sampling frequency f of the multi-channel signal synchronous acquisition card 7. d =2×10 6 Hz, multi-channel signal synchronous acquisition card 7 acquires the detection value D0(t) of the first single-pixel detector 2 within 5 seconds. q (i.e., the sequence of zeroth probe values), Where q = 0, 1, 2, ..., Q represents the sampling point number of the multi-channel signal synchronous acquisition card 7, and q is a positive integer. When the light emitted by the detection light source 1 passes through the gap between the fan blades, D0(t) q (t) represents a low voltage signal. When the light emitted by the detector light source 1 is reflected by the fan blades, D0(t) q The signal is a high voltage signal. Within one motion cycle of the target object 9, there will be 7 changes from low voltage to high voltage signal. During the signal changes from low voltage to high voltage corresponding to the same blade in different cycles of the target object 9, the collected detection value D1(t) is used to determine the voltage level. q The sampling interval Δq between sampling points whose voltage values ​​reach half the size of a high-voltage signal and the signal sampling frequency f of the multi-channel signal synchronous acquisition card. d Calculate the motion period of target object 9 Calculate the maximum period T of the motion of target object 9. max and average period And set the modulation rate f of the spatial light modulator 3. m This setting satisfies f d f m T max It is a positive real number.

[0097] S12, the detection light source 1 emits a light beam to the target object 9, and the first single-pixel detector 2 detects the light signal from the target object 9; the controller 8 controls the multi-channel signal synchronous acquisition card 7 to operate at a preset sampling frequency f.d The detection values ​​of the first single-pixel detector 2 are acquired synchronously. The spatial light modulator 3 switches the synchronous output signal of the modulation pattern. The detection value of the second single-pixel detector 6 Where, k c =0,1,2,…,K c , indicating the sampling point number of the multi-channel signal synchronous acquisition card 7, k c The integer is positive; simultaneously, controller 8 controls spatial light modulator 3 to apply 78,642 pre-generated modulation patterns P with different spatial distributions. n The light is sequentially loaded into the spatial light modulator 3, according to the preset modulation rate f. m Modulate the light field.

[0098] S13, Based on the output signal of spatial light modulator 3 The characteristic of switching from a low-voltage signal to a high-voltage signal when changing modulation patterns is that the starting sampling point of the first modulation pattern is set to k=0. The signal sampling sequence of the multi-channel signal synchronous acquisition card 7 is reordered, and the detection value of the output signal of the spatial light modulator 3 by the multi-channel signal synchronous acquisition card 7 is represented as D. m (t k The detection value of the first single-pixel detector 2 is represented as D1(t). k (i.e., the first detection value sequence), the detection value of the second single-pixel detector 6 is represented as D2(t) k (i.e., the second probe value sequence), where, Where k = 0, ±1, ±2, ..., ±K, k is an integer; all sampling point indices are segmented according to each modulation pattern to obtain the set K of sampling point indices corresponding to the nth modulation pattern. m (n).

[0099] S14. Based on the characteristic of the target object 9 having 7 blades and the detection value D1(t) of the first single-pixel detector 2 k The characteristics of seven voltage changes from low to high voltage generated within one motion cycle of target object 9, and the corresponding relationship between them, are analyzed according to the motion cycle of target object 9, and the detected value D2(t) is analyzed. k The sampling points of ) are segmented to obtain D2(t) k The number of sampling points S in the j-th period j and the sequence number k of the starting sampling point of this period 1 (j), where j represents the sequence number of the motion cycle, j = 1, 2, ..., J, S j J is a positive integer, k 1 (j) is an integer.

[0100] S15, Based on the detected value D2(t) k The number of sampling points S in the j-th period j and the sequence number k of the starting sampling point 1 (j), determine the phase value of the target object 9 at each sampling point within the j-th motion cycle. k 1 (j)≤k<k 1 (j)+S j , This is the first phase value sequence.

[0101] S16. Based on the number of sampling points S in different periods j The number of cycles J is specified.

[0102] S17, for phase is Determine the sampling point number of this phase value within different periods. The set K of sampling point indices corresponding to the nth modulation pattern m In (n), filter those that meet the conditions. The sampling points are used to obtain the phase value. The sampling point corresponding to the nth modulation pattern Determine the phase value The detection values ​​of the second single-pixel detector (6) corresponding to the 78,642 modulation patterns are as follows. n = 1, 2, ..., 78642.

[0103] Since the signals acquired by the multi-channel signal synchronous acquisition card 7 are discrete signals, when a signal that satisfies the condition cannot be found within the j-th period... When selecting sampling points, it is necessary to find those that satisfy... Using several sampling points near the first pixel and combining the nearest neighbor interpolation method, the detected value of the second single-pixel detector 6 is interpolated to obtain the interpolated detected value. The phase value of the position of motion is equal to

[0104] S18, Using phase value The detection values ​​of the second single-pixel detector 6 are 78,642. n = 1, 2, ..., 78642, the phase is reconstructed using the single-pixel reconstruction algorithm. Image of target object 9 below Different phases The images record the dynamic changes of an object during rotation.

[0105] Implementing the embodiments of the present invention has the following beneficial effects: A single-pixel imaging system for quasi-periodic moving objects includes a detection light source, a first single-pixel detector, a spatial light modulator, an illumination light source, an imaging lens, a second single-pixel detector, a multi-channel signal synchronous acquisition card, and a controller. Light emitted from the detection light source passes through the target object and reaches the first single-pixel detector. Light emitted from the illumination light source sequentially passes through the spatial light modulator, the imaging lens, and the target object before reaching the second single-pixel detector; or light emitted from the illumination light source sequentially passes through the target object, the imaging lens, and the spatial light modulator before reaching the second single-pixel detector. The multi-channel signal synchronous acquisition card is used to synchronously acquire signals from the first single-pixel detector, the spatial light modulator, and the second single-pixel detector. The controller is used to control the spatial light modulator to modulate the light field, control the multi-channel signal synchronous acquisition card to synchronously acquire signals, and reconstruct the image of the target object based on the acquired signals. For quasi-periodic moving objects, through... The detection light source monitors the motion period of the target object by passing through the zero-detection value sequence of the first single-pixel detector. Based on the zero-detection value sequence of the first single-pixel detector, the modulation frequency of the spatial light modulator is determined. The spatial light modulator is controlled to modulate the light field according to the modulation patterns and modulation frequencies with different spatial distributions. The second detection value sequence of the second single-pixel detector, the first detection value sequence of the first single-pixel detector, and the synchronous output signal when the spatial light modulator switches modulation patterns are collected. The image is reconstructed based on the signals corresponding to all modulation patterns under the same phase value in the second detection value sequence, thereby reducing the impact of periodic fluctuations on imaging quality and improving imaging quality. In addition, by controlling the spatial light modulator together with the modulation patterns and modulation frequencies with different spatial distributions, it is only required that the modulation frequency of the spatial light modulator is less than the reciprocal of the maximum motion period of the target object, thereby solving the problem that the maximum speed of the quasi-periodic motion of the target object is limited by the modulation rate of the spatial light modulator.

[0106] See Figure 8 This invention provides a single-pixel imaging device for a quasi-periodic moving object, comprising:

[0107] At least one processor;

[0108] At least one memory for storing at least one program;

[0109] When at least one program is executed by at least one processor, the at least one processor implements the single-pixel imaging method described above.

[0110] The memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. The memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include remote memory located remotely relative to the processor, which can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0111] It is evident that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented in this device embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0112] Furthermore, this application also discloses a computer program product or computer program stored in a computer-readable storage medium. A processor of a computer device can read the computer program from the computer-readable storage medium, and the processor executes the computer program, causing the computer device to perform the described method. Similarly, the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0113] This invention also provides a computer-readable storage medium storing a processor-executable program that, when executed by a processor, implements the above-described method.

[0114] It is understood that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0115] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A single-pixel imaging system for a quasi-periodic moving object, characterized in that, The system includes a detection light source (1), a first single-pixel detector (2), a spatial light modulator (3), an illumination light source (4), an imaging lens (5), a second single-pixel detector (6), a multi-channel signal synchronous acquisition card (7), and a controller (8). The light emitted by the detection light source (1) passes through the target object and reaches the first single-pixel detector (2). The light emitted by the illumination light source (4) passes through the spatial light modulator (3), the imaging lens (5), and the target object in sequence before reaching the second single-pixel detector (6). Alternatively, the light emitted by the illumination light source (4) passes through the target object, the imaging lens (5), and the spatial light modulator (3) in sequence before reaching the second single-pixel detector (6). The multi-channel signal synchronous acquisition card (7) is used to synchronously acquire signals from the first single-pixel detector (2), the spatial light modulator (3), and the second single-pixel detector (6). The controller (8) is used to control the spatial light modulator (3) to modulate the light field, control the multi-channel signal synchronous acquisition card (7) to synchronously acquire signals, and reconstruct the image of the target object based on the acquired signals. The image of the target object is reconstructed using the following method: Based on the periodicity of the first detection value sequence of the first single-pixel detector (2), the sampling points of the second detection value sequence of the second single-pixel detector (6) are segmented according to the motion cycle of the target object to obtain the number of sampling points in each cycle and the starting sampling point number of each cycle. Based on the number of sampling points, the sequence number of the starting sampling point, and the change characteristics within the period of the first detection value sequence, the phase value of the target object's position corresponding to each sampling point is determined, and the phase values ​​corresponding to the sampling points of the second detection value sequence are combined to form a first phase value sequence. For a phase value, in the first phase value sequence, the sampling point number of the phase value in different periods is determined, and combined with the synchronous output signal of the spatial light modulator (3) when switching patterns, the second detection value corresponding to all modulation patterns under the phase value is determined; An image of the target object is reconstructed based on the second detection values ​​corresponding to all modulation patterns under the said phase value; if the phase value does not exist in a certain period in the first phase value sequence, the second detection value sequence is interpolated according to the interpolation method to determine the second detection values ​​corresponding to all modulation patterns under the said phase value.

2. The single-pixel imaging system according to claim 1, characterized in that, The detection light source (1) and the illumination light source (4) have different wavelengths or polarization states; the first single-pixel detector (2) and the second single-pixel detector (6) are provided with color filters of corresponding wavelengths or polarizers of corresponding polarization states.

3. The single-pixel imaging system according to claim 1, characterized in that, Both the first single-pixel detector (2) and the second single-pixel detector (6) include at least one condenser lens and at least one single-pixel photodetector.

4. The single-pixel imaging system according to claim 1, characterized in that, The detection light source (1) includes multiple sub-light sources, and the first single-pixel detector (2) includes multiple sub-detectors. One sub-light source corresponds to one sub-detector, and the signal of each sub-detector is synchronously acquired by a multi-channel signal synchronous acquisition card (7).

5. A single-pixel imaging method for a quasi-periodic moving object, characterized in that, Applied to the single-pixel imaging system according to any one of claims 1-4, comprising: Turn on the detection light source (1) to emit a beam to the target object, control the multi-channel signal synchronous acquisition card (7) to acquire the zeroth detection value sequence of the first single pixel detector (2), and determine the modulation frequency of the spatial light modulator (3) based on the zeroth detection value sequence; Generate modulation patterns with different spatial distributions, use the modulation patterns and the modulation frequency to control the spatial light modulator (3) to modulate the light field, and control the multi-channel signal synchronous acquisition card (7) to acquire the first detection value sequence of the first single pixel detector (2), the synchronous output signal of the spatial light modulator (3) when switching the modulation pattern, and the second detection value sequence of the second single pixel detector (6). Reconstructing an image of the target object based on the first detection value sequence, the second detection value sequence, and the synchronous output signal during the switching modulation pattern; specifically including: Based on the periodicity of the first detection value sequence, the sampling points of the second detection value sequence are segmented according to the motion cycle of the target object to obtain the number of sampling points in each cycle and the starting sampling point number of each cycle. Based on the number of sampling points, the sequence number of the starting sampling point, and the change characteristics within the period of the first detection value sequence, the phase value of the target object's position corresponding to each sampling point is determined, and the phase values ​​corresponding to the sampling points of the second detection value sequence are combined to form a first phase value sequence. For a phase value, in the first phase value sequence, the sampling point number of the phase value in different periods is determined, and combined with the synchronous output signal of the spatial light modulator (3) when switching patterns, the second detection value corresponding to all modulation patterns under the phase value is determined; An image of the target object is reconstructed based on the second detection values ​​corresponding to all modulation patterns under the said phase value; if the phase value does not exist in a certain period in the first phase value sequence, the second detection value sequence is interpolated according to the interpolation method to determine the second detection values ​​corresponding to all modulation patterns under the said phase value.

6. The single-pixel imaging method according to claim 5, characterized in that, The determination of the modulation frequency of the spatial light modulator (3) based on the zeroth probe value sequence specifically includes: The maximum period of the periodic motion of the target object is determined based on the periodic characteristics of the zeroth detection value sequence; The modulation frequency of the spatial light modulator (3) is determined based on the maximum period.

7. A single-pixel imaging device for a quasi-periodic moving object, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor performs the method as described in any one of claims 5-6.

8. A computer-readable storage medium storing a processor-executable program, characterized in that, The processor-executable program, when executed by the processor, is used to perform the method as described in any one of claims 5-6.

Images