Spectral registration methods and systems

Abstract

This application relates to the field of spectral detection, and provides a spectral registration method and system. The spectral registration method includes: acquiring a first interference spectrum of a first channel and a second interference spectrum of a second channel obtained by scanning a mirror of an OCT device; selecting a first spectrum to be registered from the first interference spectrum; selecting a second spectrum to be registered from the second interference spectrum with the same bandwidth as the first spectrum to be registered; performing matching calculations on the first and second spectra to be registered, and adjusting the bandwidth of the first and second spectra to be registered based on the matching calculation results until the first spectral range of the first channel and the second spectral range of the second channel matching the first spectral range are obtained; therefore, spectral registration of the first and second channels can be achieved without adding other optical paths and devices to the OCT device. The system is simple, small in size, does not increase cost, and the registration process is simple.

Description

Technical Field

[0001] This application belongs to the field of spectral detection, and in particular relates to a spectral registration method and system. Background Technology

[0002] Optical coherence tomography (OCT) is a non-invasive imaging technique that uses a low-coherence light source to measure the amplitude and echo delay of backscattered light, enabling the acquisition of high-resolution images of the microstructure of biological tissues and materials. In balanced-probe spectral domain OCT, sample detection is performed by measuring the interference spectra of two channels with a 180° phase difference of the same sample. This eliminates or reduces imaging artifacts caused by self-coherence terms, thereby improving the signal-to-noise ratio.

[0003] To improve measurement accuracy, the interference spectra of the two channels need to be registered. Existing registration methods generally calibrate the correspondence between the wavelengths and pixels of the two interference spectra, which requires the use of standard light sources with known discrete spectral lines, such as mercury lamps or helium-neon lasers. Therefore, additional optical paths, switching mechanisms, and detection units need to be added to the spectrometer, increasing the complexity, size, and cost of the system, as well as the complexity of the registration process. Summary of the Invention

[0004] In view of this, embodiments of this application provide a spectral registration method and system that can solve the problems of complex systems, large size, high cost, and complicated registration processes in existing registration methods.

[0005] A first aspect of this application provides a spectral registration method, including:

[0006] The first interference spectrum and the second interference spectrum obtained by scanning the reflector of the OCT device are acquired. The first interference spectrum is received through the first channel and the second interference spectrum is received through the second channel. The phase difference between the first interference spectrum and the second interference spectrum is 180°.

[0007] Select the first spectrum to be registered from the first interference spectrum;

[0008] A second spectrum to be registered is selected from the second interference spectrum, wherein the width of the band of the second spectrum to be registered is the same as the width of the band of the first spectrum to be registered.

[0009] Matching calculations are performed on the first and second spectra to be registered. Based on the results of the matching calculations, the band ranges of the first and second spectra to be registered are adjusted until a first spectral range of the first channel and a second spectral range of the second channel that matches the first spectral range are obtained. The matching calculations include calculating the values ​​of the normalized correlation functions of the first and second spectra to be registered, and calculating the matching degree of the peaks and troughs of the first and second spectra to be registered.

[0010] In one embodiment, adjusting the band range of the first spectrum to be registered and the band range of the second spectrum to be registered based on the result of the matching calculation until a first spectral range of the first channel and a second spectral range of the second channel matching the first spectral range are obtained, including:

[0011] If the first spectrum to be registered and the second spectrum to be registered are successfully matched, the width of the band of the first spectrum to be registered is expanded until the matching quality of the expanded first spectrum to be registered and the expanded second spectrum to be registered is less than a first set value. The first spectral range is determined based on the expanded first spectrum to be registered, and the second spectral range is determined based on the expanded second spectrum to be registered. The successful matching includes the value of the normalized correlation function being less than a first threshold and the matching degree being greater than a second threshold.

[0012] If the first spectrum to be registered fails to match the second spectrum to be registered, and there is no band in the second interference spectrum that successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is reduced until the matching quality of the reduced first spectrum to be registered and the reduced second spectrum to be registered is greater than a second set value. The first spectral range is determined based on the reduced first spectrum to be registered, and the second spectral range is determined based on the reduced second spectrum to be registered.

[0013] In one embodiment, the method further includes:

[0014] If the first spectrum to be registered fails to match the second spectrum to be registered, then the band range of the second spectrum to be registered is adjusted.

[0015] If the adjusted second spectrum to be registered successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is expanded.

[0016] If the adjusted second registration spectrum fails to match the first registration spectrum, it is determined that there is no band in the second interference spectrum that successfully matches the first registration spectrum.

[0017] In one embodiment, the matching degree is determined based on the number of troughs in the second spectrum to be registered that correspond to the peaks of the first spectrum to be registered, and the number of peaks in the second spectrum to be registered that correspond to the troughs of the first spectrum to be registered.

[0018] In one embodiment, if the first spectrum to be registered successfully matches the second spectrum to be registered, then the bandwidth of the first spectrum to be registered is expanded, including:

[0019] If the first spectrum to be registered successfully matches the second spectrum to be registered, and the third spectrum to be registered in the first channel and the fourth spectrum to be registered in the second channel are successfully matched after adjusting the distance of the mirror, then the width of the band of the first spectrum to be registered is expanded.

[0020] In one embodiment, both the first and second spectra to be registered represent the correspondence between wavelength and signal intensity. Matching calculations are performed on the first and second spectra to be registered, including:

[0021] Both the first and second spectra to be registered are converted into the correspondence between wavelength and signal intensity under the condition of uniform wavenumber distribution;

[0022] Matching calculations are performed on the first and second spectra to be registered after conversion.

[0023] In one embodiment, converting both the first and second spectra to be registered into a wavelength-signal intensity correspondence under a uniform wavenumber distribution includes:

[0024] Construct an equally spaced first wavenumber sequence based on the start and end wavelengths of the first spectrum to be registered;

[0025] Based on the first wavenumber sequence and the corresponding signal intensity, the correspondence between the wavelength and signal intensity of the first spectrum to be registered under the condition of uniform wavenumber distribution is obtained;

[0026] A second wavenumber sequence with equal spacing is constructed based on the start wavelength and end wavelength of the second spectrum to be registered, wherein the spacing of the first wavenumber sequence is the same as the spacing of the second wavenumber sequence;

[0027] Based on the second wavenumber sequence and the corresponding signal intensity, the correspondence between the wavelength and signal intensity of the second spectrum to be registered under the condition of uniform wavenumber distribution is obtained.

[0028] In one embodiment, after obtaining the first spectral range of the first channel and the second spectral range of the second channel that matches the first spectral range, the method further includes:

[0029] Acquire the first detection signal of the first channel and the second detection signal of the second channel obtained by scanning the sample with the OCT device;

[0030] The detection information of the sample is determined based on the difference between the first detection signal in the first spectral range and the second detection signal in the second spectral range.

[0031] A second aspect of this application provides a spectral registration apparatus, comprising:

[0032] The acquisition module is used to acquire the first interference spectrum and the second interference spectrum obtained by scanning the reflector of the OCT device. The first interference spectrum is received through the first channel, and the second interference spectrum is received through the second channel. The phase difference between the first interference spectrum and the second interference spectrum is 180°.

[0033] The first selection module is used to select a first spectrum to be registered from the first interference spectrum;

[0034] The second selection module is used to select a second spectrum to be registered from the second interference spectrum, wherein the width of the band of the second spectrum to be registered is the same as the width of the band of the first spectrum to be registered.

[0035] The registration module is used to perform matching calculations on the first spectrum to be registered and the second spectrum to be registered, and adjust the band range of the first spectrum to be registered and the band range of the second spectrum to be registered according to the result of the matching calculation, until a first spectral range of the first channel and a second spectral range of the second channel that matches the first spectral range are obtained; the matching calculation includes calculating the value of the normalized correlation function of the first spectrum to be registered and the second spectrum to be registered, and calculating the matching degree of the peaks and troughs of the first spectrum to be registered and the second spectrum to be registered.

[0036] A third aspect of this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the spectral registration method as described in the first aspect above.

[0037] A fourth aspect of this application provides a spectral registration system, including an OCT device, a mirror, and an electronic device as described in the third aspect above.

[0038] A fifth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the spectral registration method as described in the first aspect above.

[0039] A sixth aspect of this application provides a computer program product that, when run on an electronic device, causes the electronic device to perform the spectral registration method described in any one of the first aspects.

[0040] The beneficial effects of this application embodiment compared with the prior art are as follows: By scanning the reflector with an OCT device, the first interference spectrum of the first channel and the second interference spectrum of the second channel with a phase difference of 180° are obtained. A first registration spectrum is selected from the first interference spectrum, and a second registration spectrum is selected from the second interference spectrum. The normalized correlation function values ​​of the first and second registration spectra are calculated, as well as the matching degree of the peaks and troughs of the first and second registration spectra are calculated to determine the matching result. Then, based on the matching result, the first spectral range of the first channel and the second spectral range of the second channel matching the first spectral range are adjusted, thereby solving the spectral shift problem between the first and second channels and matching the spectral ranges of the first and second channels. Therefore, spectral registration of the first and second channels can be achieved without adding other optical paths and devices to the OCT device. The system is simple, small in size, does not increase cost, and the registration process is simple. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0042] Figure 1 This is a schematic diagram of an OCT device provided in an embodiment of this application;

[0043] Figure 2 This is a schematic diagram illustrating the implementation process of a spectral registration method provided in an embodiment of this application;

[0044] Figure 3 This is a flowchart of a spectral registration method provided in an embodiment of this application;

[0045] Figure 4 This is a schematic diagram of a spectral registration device provided in an embodiment of this application;

[0046] Figure 5 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0047] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0048] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0049] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0051] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0052] Furthermore, in the description of this application, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0053] The spectral registration method provided in this application is illustrated below.

[0054] The spectral registration method provided in this application is used to register the interference spectra received by two channels of an OCT device. The OCT device is a balanced detection spectral domain OCT.

[0055] For example, such as Figure 1As shown, the OCT equipment includes a superluminescent diode (SLD) light source, a fiber optic circulator, a coupler FC, a collimating lens CL1 for the measurement arm, a scanning galvanometer Gavo for the measurement arm, lenses L1 and L2, a collimating lens CL2 for the reference arm, a reflector M1 for the reference arm, and a spectrometer. The spectrometer includes a collimating lens CL3, a diffraction grating DG, a focusing lens L3, and a line scan camera.

[0056] During sample detection, light emitted from the SLD source passes through an optical fiber circulator and enters the coupler FC, splitting into two beams: a probe beam and a reference beam. The probe beam sequentially passes through the collimating lens CL1 of the measurement arm, the scanning mirror Gavo of the measurement arm, lens L1, and lens L2 before illuminating the sample. After scattering and reflection from the sample, it returns to the coupler FC via the same path. The reference beam passes through the collimating lens CL2 of the reference arm and illuminates the reflecting mirror M1 of the reference arm. After reflection by the reflecting mirror M1, it returns to the coupler FC via the same path. The probe beam and the reference beam, returning via the same path, interfere within the coupler FC, producing two antiphase interference spectra, i.e., the phase difference between the two interference spectra is 180°. The two antiphase interference spectra are incident on the same spectrometer at different angles; for example, one interference spectrum enters the spectrometer directly, while the other enters the spectrometer after passing through the optical fiber circulator. Within the spectrometer, the two antiphase interference spectra pass through the collimating lens CL3, the diffraction grating DG, and the focusing lens L3 before being imaged on the linear array camera. For example, for a 4096-pixel linear array camera, the two antiphase interference spectra correspond to pixel positions 1-2048 and 2049-4096, respectively.

[0057] Based on the pixel information acquired by the linear scan camera, the representation of the interference spectrum of the two channels in wavenumber k space can be obtained. and .

[0058]

[0059] ；

[0060]

[0061] 。

[0062] in, This represents the amplitude of the reflected reference light. and Let z and z' represent the amplitudes of the backscattered signals at depths z and z' of the sample, respectively. This represents the refractive index of the tissue being measured. In both formulas, the first term is a DC bias term independent of optical path length, primarily dependent on the spectral intensity of the reference light. The second term represents the interference signal between the reference and probe light, used to determine the tissue structure image. The third term represents the self-coherence term, which is the self-coherent signal resulting from the interference between the signals reflected back from different depths of the sample by the probe light. By subtracting the two signals to determine sample information, imaging artifacts caused by the self-coherence term can be eliminated or reduced.

[0063] However, slight differences in the optical paths and grating installation angles between the two channels can cause spectral shifts, meaning the wavelengths of the two channels cannot be directly mapped to determine sample detection information. Therefore, spectral registration of the two channels is necessary.

[0064] Please see the appendix Figure 2 The spectral registration method provided in one embodiment of this application includes steps S201 to S204.

[0065] S201: Obtain the first interference spectrum and the second interference spectrum obtained by scanning the reflector of the OCT device. The first interference spectrum is received through the first channel, and the second interference spectrum is received through the second channel. The phase difference between the first interference spectrum and the second interference spectrum is 180°.

[0066] Specifically, the reflector is placed at the location of the sample in the OCT device. The probe light sequentially passes through the collimating lens CL1 of the measurement arm, the scanning mirror Gavo of the measurement arm, lens L1, and lens L2 before illuminating the reflector. After reflection, it returns to the coupler FC via the same path. The reference light passes through the collimating lens CL2 of the reference arm before illuminating the reflector M1 of the reference arm. After reflection, it returns to the coupler FC via the same path. The probe light and the reference light, after returning via the same path, interfere within the coupler FC, producing two interference spectra with a phase difference of 180°. The two interference spectra are incident on the same spectrometer at different angles, corresponding to different channels (different pixel positions) of the linear array camera. These two channels are designated as the first channel and the second channel, respectively. The first interference spectrum is obtained from the data read from the first channel, and the second interference spectrum is obtained from the data read from the second channel.

[0067] For example, the data read from the first channel represents the correspondence between pixels and signal intensities in the first channel. This correspondence is then converted into a correspondence between wavelength and signal intensity to obtain the first interference spectrum. For instance, in the spectral graph corresponding to the data read from the first channel, the horizontal axis represents pixels, and the vertical axis represents signal intensity. By converting the pixels on the horizontal axis into wavelengths, the first interference spectrum is obtained. Similarly, the data read from the second channel represents the correspondence between pixels and signal intensities in the second channel. This correspondence is then converted into a correspondence between wavelength and signal intensity to obtain the second interference spectrum. For each pixel, the diffraction angle of the light can be determined based on the pixel's position. Given the angle of incidence of the light ray Grating constant And in the case of diffraction order m, according to the grating equation =mλ can determine the wavelength corresponding to each pixel position, and thus obtain the correspondence between wavelength and signal strength.

[0068] In one embodiment, a precision displacement stage can be used to move the reflector, thereby changing the optical path difference between the reference arm and the measuring arm. Scanning the reflector at different optical path difference positions yields interference spectra corresponding to different optical path differences, which are then used for subsequent registration. This improves registration accuracy by enabling the registration of interference spectra corresponding to different optical path difference positions. Smaller optical path differences correspond to lower-frequency interference signals, while larger optical path differences correspond to higher-frequency interference signals. Based on the total imaging depth of the OCT equipment, interference signals corresponding to different optical path differences can be acquired within the imaging depth range, ensuring that complete interference signals can be acquired from low frequency (smaller optical path difference) to high frequency (larger optical path difference).

[0069] S202: Select the first spectrum to be registered from the first interference spectrum.

[0070] In this study, both the first and second interference spectra represent a wavelength-to-signal-intensity correspondence. Since the wavelengths of the first and second interference spectra are not in a one-to-one correspondence, if the entire wavelength range of the first interference spectrum is used for registration with the second interference spectrum, the spectral shift between them will prevent registration, resulting in data loss. Therefore, selecting a portion of the spectral signal from the first interference spectrum as the first registration spectrum allows for accurate registration of the first and second interference spectra. For example, the data in the first and last 5% of the first interference spectrum is discarded, and the middle 90% is used as the first registration spectrum.

[0071] S203: Select a second spectrum to be registered from the second interference spectrum, wherein the width of the band of the second spectrum to be registered is the same as the width of the band of the first spectrum to be registered.

[0072] Specifically, the width of the band of the first spectrum to be registered can be determined based on the starting and ending wavelengths of the first spectrum to be registered, and the width of the band of the first spectrum to be registered can be used as the width of the band of the second spectrum to be registered. The starting wavelength of the second spectrum to be registered can be the starting wavelength of the second interference spectrum, or it can be selected according to the measurement requirements. The ending wavelength of the second spectrum to be registered can be determined based on the starting wavelength and the width of the band, thus determining the second spectrum to be registered.

[0073] S204: Perform matching calculations on the first and second spectra to be registered, and adjust the band ranges of the first and second spectra to be registered according to the results of the matching calculations until a first spectral range of the first channel and a second spectral range of the second channel that matches the first spectral range are obtained; the matching calculations include calculating the values ​​of the normalized correlation functions of the first and second spectra to be registered, and calculating the matching degree of the peaks and troughs of the first and second spectra to be registered.

[0074] In one embodiment, since the pixels in the spectral signal acquired by the linear scan camera are equally spaced and the relationship between pixels and wavelength is polynomial, the wavelength distribution in the first and second interference spectra obtained based on the pixel-wavelength relationship is uneven. This results in the inability to align the wavelengths of the first and second spectra to be registered, affecting the registration accuracy. Therefore, both the first and second spectra to be registered are first converted into a wavelength-signal intensity correspondence under a uniform wavenumber distribution. Then, matching calculations are performed on the converted first and second spectra to improve the registration accuracy.

[0075] In one embodiment, a first wavenumber sequence with equal spacing is constructed based on the start and end wavelengths of the first spectrum to be registered. The wavelength-to-signal-intensity relationship of the first spectrum to be registered under a uniform wavenumber distribution is obtained based on the first wavenumber sequence and its corresponding signal intensity. A second wavenumber sequence with equal spacing is constructed based on the start and end wavelengths of the second spectrum to be registered, with the spacing between the first and second wavenumber sequences being the same. The wavelength-to-signal-intensity relationship of the second spectrum to be registered under a uniform wavenumber distribution is obtained based on the second wavenumber sequence and its corresponding signal intensity.

[0076] For example, wavelength can be converted to wavenumber using the formula k = c / λ, where λ represents wavelength, k represents wavenumber, and c represents the speed of light. For the first spectrum to be registered, the wavenumbers corresponding to the starting wavelength and the ending wavelength can be obtained using the formula. An equally spaced first wavenumber sequence is then constructed based on these wavenumbers. For example, the first wavenumber sequence could be KA1, KA2, ..., KAN, with a total of N (e.g., N = 2048) wavenumbers, spaced at intervals... for The wavelengths corresponding to each wavenumber can be determined from the first wavenumber sequence, resulting in a wavelength sequence under a uniform wavenumber distribution. Based on this wavelength sequence and the signal intensity corresponding to each wavelength of the first spectrum to be registered, the correspondence between wavelength and signal intensity under a uniform wavenumber distribution can be obtained. For example, cubic spline interpolation can be used to resample the first spectrum to be registered, yielding the signal intensity corresponding to each wavelength under a uniform wavenumber distribution.

[0077] Similarly, for the second spectrum to be registered, the wavenumbers corresponding to the starting wavelength and the ending wavelength can be obtained according to the formula. A second wavenumber sequence with the same spacing as the first wavenumber sequence is then constructed based on these wavenumbers. Each wavenumber in the second wavenumber sequence is then converted to its corresponding wavelength, resulting in a wavelength sequence under a uniform wavenumber distribution. Based on the wavelength sequence under a uniform wavenumber distribution and the signal intensity corresponding to each wavelength of the second spectrum to be registered, the correspondence between wavelength and signal intensity under a uniform wavenumber distribution is obtained.

[0078] In one embodiment, according to the formula Calculate the normalized correlation function values ​​for the first and second spectra to be registered, where, This represents the signal intensity corresponding to each wavelength in the first spectrum to be registered. Let μ_A represent the signal intensity corresponding to each wavelength in the second spectrum to be registered, μ_B represent the mean signal intensity of the first spectrum to be registered, σ_A represent the standard deviation of the signal intensity of the first spectrum to be registered, and σ_B represent the standard deviation of the signal intensity of the second spectrum to be registered. The cross-correlation function has a value of -1 when the first and second spectra are completely oppositely aligned, and a value of 1 when the first and second spectra are identical.

[0079] In one embodiment, the matching degree between the first and second spectra to be registered is determined based on the number of troughs in the second spectrum to be registered that correspond to the peaks of the first spectrum to be registered, and the number of peaks in the second spectrum to be registered that correspond to the troughs of the first spectrum to be registered. For example, for each peak in the first spectrum to be registered, the number of troughs in the second spectrum to be registered that correspond to the peaks of the first spectrum to be registered is counted; for each trough in the first spectrum to be registered, the number of peaks in the second spectrum to be registered that correspond to the troughs of the first spectrum to be registered is counted, thus obtaining the matching number. The ratio of the matching number to the total number of peaks and troughs in the first spectrum to be registered is the matching degree. Here, the correspondence between the peaks of the first spectrum to be registered and the troughs of the second spectrum to be registered means that the difference between the wavelengths corresponding to the peaks and troughs is within a set range.

[0080] Matching calculations are performed on the first and second spectra to be registered. If the value of the normalized correlation function is less than a first threshold and the matching degree is greater than a second threshold, the matching is considered successful; otherwise, the matching is considered unsuccessful. The first threshold can be -0.7, and the second threshold can be 0.6.

[0081] In one embodiment, if the first and second spectra to be registered successfully match, the width of the band of the first spectra to be registered is expanded until the matching quality of the expanded first and second spectra to be registered is less than a first preset value. A first spectral range is determined based on the expanded first spectra to be registered, and a second spectral range is determined based on the expanded second spectra to be registered. If the first and second spectra to be registered fail to match, and there is no band in the second interference spectrum that successfully matches the first spectra to be registered, the width of the band of the first spectra to be registered is narrowed until the matching quality of the narrowed first and second spectra to be registered is greater than a second preset value. A first spectral range is determined based on the narrowed first spectra to be registered, and a second spectral range is determined based on the narrowed second spectra to be registered.

[0082] Specifically, if the first and second spectra to be registered are successfully matched, it means that the first and second spectra to be registered meet the condition of anti-alignment, and the corresponding bands after registration can be directly used for signal detection. Since the first spectrum to be registered is a part of the first interference spectrum and the second spectrum to be registered is a part of the second interference spectrum, by expanding the first and second spectra to be registered, the effective bands can be maximized and the data utilization rate can be improved.

[0083] For example, if the first and second spectra to be registered successfully match, the bandwidth of the first and second spectra to be registered can be increased by 1%, resulting in expanded first and second spectra to be registered. The matching calculation is then performed again on the expanded first and second spectra to be registered. If the match is still successful, the bandwidth of the first and second spectra to be registered is further expanded until the matching quality of the expanded first and second spectra to be registered is less than a first preset value. The matching quality is determined based on the value of the normalized correlation function and the degree of matching. For example, if the value of the normalized correlation function decreases by more than 5% relative to the maximum value of the normalized correlation function during the matching process, or if the degree of matching decreases by more than 5% relative to the maximum value of the degree of matching during the matching process, then the matching quality is determined to be less than the first preset value. When the matching quality between the expanded first and second spectra to be registered is less than a first preset value, the spectral range of the expanded first spectra to be registered is taken as the first spectral range, and the spectral range of the expanded second spectra to be registered is taken as the second spectral range. Specifically, the starting and ending wavelengths of the expanded first spectra to be registered are taken as the starting and ending wavelengths of the first spectral range, and the starting and ending wavelengths of the expanded second spectra to be registered are taken as the starting and ending wavelengths of the second spectral range. The first spectral range of the first channel corresponds to the second spectral range of the second channel.

[0084] It is understandable that during the process of expanding the first and second registration spectra, if the expanded first registration spectrum exceeds the spectral range of the first interference spectrum, or the expanded second registration spectrum exceeds the spectral range of the second interference spectrum, the expansion is stopped, and the first and second spectral ranges are determined based on the previously obtained expanded first and second registration spectra.

[0085] If the first and second spectra to be registered fail to match, the spectral range of the second spectra is adjusted, i.e., the start and end wavelengths of the second spectra are redefined to obtain an updated second spectra. Matching calculations are then performed on the first and updated second spectra. If the match still fails, the start and end wavelengths of the second spectra are updated again until a successful match is achieved. If a successful match is achieved, the first and updated spectra are expanded using the same method to obtain a first spectral range and a second spectral range.

[0086] If, after adjusting the band range of the second spectrum to be registered, the initial or final wavelength still exceeds the spectral range of the second interference spectrum, and the match with the first spectrum to be registered still fails, meaning that both the adjusted second and first spectra fail to match, then it is determined that there is no band in the second interference spectrum that successfully matches the first spectrum to be registered. In this case, the width of the band of the first spectrum to be registered is reduced. For example, the width of the band of the first spectrum to be registered can be reduced by 1%, and the width of the band of the second spectrum to be registered can also be reduced, resulting in reduced first and second spectra to be registered. The matching calculation is then performed again on the reduced first and second spectra to be registered. If the match still fails, the width of the bands of both the first and second spectra to be registered is reduced further until the matching quality of the reduced first and second spectra to be registered is greater than a second set value. The spectral range of the reduced first spectrum to be registered is then used as the first spectral range, and the spectral range of the reduced second spectrum to be registered is used as the second spectral range. The second setting value can be a condition for a successful match, such as the value of the normalized correlation function being less than the first threshold and the matching degree being greater than the second threshold, or it can be other setting values.

[0087] It is understandable that, in the process of narrowing the width of the first and second bands of the spectrum to be registered, if the narrowed width of the first band of the spectrum to be registered is less than the set value (e.g., 80%) of the width of the first band of the interference spectrum, and the matching still fails, then the first and second spectral ranges are determined based on the narrowed first and second bands of the spectrum to be registered with the best matching quality.

[0088] In one embodiment, interference spectra corresponding to multiple optical path differences are obtained by adjusting the position of the reflector. The wavelengths of each interference spectrum are truncated to obtain registration spectra corresponding to different optical path differences. The registration spectra of the first channel corresponding to the multiple optical path differences are taken as the third registration spectra, and the registration spectra of the second channel corresponding to the multiple optical path differences are taken as the fourth registration spectra. If the first and second registration spectra are successfully matched, the same method is used to match the third and fourth registration spectra corresponding to each optical path difference. If all third and fourth registration spectra are successfully matched, the width of the first registration spectrum is expanded, and the wavelength of the expanded second registration spectrum is determined. If any set of third and fourth registration spectra fails to match, the expansion stops, and the first and second spectral ranges are determined based on the previously obtained expanded first and second registration spectra. By registering the interference spectra corresponding to different optical path differences, the spectra of the first channel and the second channel can be accurately registered at any optical path difference position.

[0089] In the above embodiments, a first registration spectrum is first selected from the first interference spectrum, and a second registration spectrum is selected from the second interference spectrum. If the first and second registration spectra are successfully matched, the width of the band of the first registration spectrum is expanded for further matching, thereby determining a first spectral range and a second spectral range that meet the preset matching quality, which can improve data utilization. If the first and second registration spectra fail to match, and there is no band in the second interference spectrum that is successfully matched with the first registration spectrum, the width of the band of the first registration spectrum is narrowed for further matching, thereby determining a first spectral range and a second spectral range that meet the preset matching quality, so as to ensure that the first and second spectral ranges have high matching accuracy.

[0090] In one embodiment, after determining the first spectral range and the second spectral range, a first detection signal from the first channel and a second detection signal from the second channel obtained by scanning the sample with an OCT device are acquired. Based on the difference between the first detection signal within the first spectral range and the second detection signal within the second spectral range, the sample's detection information is determined. For example, the sample is scanned multiple times laterally. For each lateral scan, a Fourier transform is performed on the corresponding difference signal to obtain the sample's axial depth profile information. Based on the axial depth profile information corresponding to multiple lateral scans, a two-dimensional or three-dimensional OCT structural image of the sample can be reconstructed.

[0091] For example, the flow of the spectral registration method provided in one embodiment of this application is as follows: Figure 3 As shown.

[0092] The OCT device has two channels: Channel A and Channel B. The original dual-channel spectral data S1, S2, ..., Sn are acquired by scanning mirrors at different optical path difference positions. The original spectral data represents the correspondence between pixels and signal intensities. For S1, wavelength calibration is performed on the original spectral data, converting the pixel-to-signal-intensity correspondence into a wavelength-to-signal-intensity correspondence, resulting in the first interference spectrum of Channel A and the second interference spectrum of Channel B. Then, a portion of the wavelength band is extracted from the first interference spectrum to initialize the effective range of the Channel A spectrum (the first spectrum to be registered), determining the starting wavelength λ of Channel B. B1 Based on the effective range of the spectrum of channel A, the termination wavelength of channel B is determined, and thus the effective range of the spectrum of channel B (the second spectrum to be registered) is obtained.

[0093] The first and second spectra to be registered are resampled to obtain the first and second spectra to be registered under a uniform wavenumber distribution. Matching calculations are performed on the first and second spectra to be registered, and the count is recorded. If the first and second spectra to be registered are successfully matched, the count is incremented by 1. If the count is less than n, the same method is used to match the spectrum corresponding to the next optical path difference until the count reaches n, completing the registration of the spectra of S1, S2, ..., Sn. After completing the spectral registration at all optical path difference positions, the expansion stage begins, expanding the range of the first spectra to be registered and re-performing the matching calculation. If the first and second spectra to be registered fail to match, the starting wavelength λ of channel B is adjusted. B1 For example, each time the wavelength value increases by 1%, the ending wavelength λ of the adjusted second spectrum to be registered is determined based on the width Δλ of the first spectrum to be registered. B1+ Does Δλ exceed 100% of the maximum range of the second interference spectrum? If it does not exceed 100% of the maximum range, the adjusted second spectrum to be registered is resampled to match the first spectrum to be registered. If it exceeds 100% of the maximum range, the contraction phase begins, reducing the band range of the first spectrum to be registered, and the matching calculation is performed again. After performing matching calculations on the expanded or contracted spectra, the optimal matching ranges of channels A and B that satisfy the matching quality are recorded, resulting in the first spectral range and the second spectral range.

[0094] An OCT device is used to perform balanced detection on the sample, and the interference signals in the first and second spectral ranges are calculated. The calculation results are then subjected to a fast Fourier transform (FFT) to obtain the depth profile information of the sample. Based on the depth profile information of the sample, an OCT image of the sample is generated.

[0095] In the above embodiments, by scanning the reflector with an OCT device, the first interference spectrum of the first channel and the second interference spectrum of the second channel with a phase difference of 180° are obtained. A first registration spectrum is selected from the first interference spectrum, and a second registration spectrum is selected from the second interference spectrum. The normalized correlation function values ​​of the first and second registration spectra are calculated, as well as the matching degree of the peaks and troughs of the first and second registration spectra, to determine the matching result. Then, based on the matching result, the first spectral range of the first channel and the second spectral range of the second channel matching the first spectral range are adjusted, thereby solving the spectral shift problem between the first and second channels and matching the spectral ranges of the first and second channels. Therefore, spectral registration of the first and second channels can be achieved without adding other optical paths and devices to the OCT device. The system is simple, small in size, and does not increase cost. The registration process is also simple, improving the stability of the OCT device. Using the registered OCT device for sample detection improves imaging quality and signal-to-noise ratio.

[0096] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0097] Corresponding to the spectral registration method described in the above embodiments, Figure 4 A structural block diagram of the spectral registration device provided in the embodiments of this application is shown. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0098] like Figure 4 As shown, the spectral registration device includes an acquisition module 41, a first selection module 42, a second selection module 43, and a registration module 44.

[0099] The acquisition module 41 is used to acquire the first interference spectrum and the second interference spectrum obtained by scanning the reflector of the OCT device. The first interference spectrum is received through the first channel, and the second interference spectrum is received through the second channel. The phase difference between the first interference spectrum and the second interference spectrum is 180°.

[0100] The first selection module 42 is used to select a first spectrum to be registered from the first interference spectrum;

[0101] The second selection module 43 is used to select a second spectrum to be registered from the second interference spectrum, wherein the width of the band of the second spectrum to be registered is the same as the width of the band of the first spectrum to be registered.

[0102] The registration module 44 is used to perform matching calculations on the first spectrum to be registered and the second spectrum to be registered, and adjust the band range of the first spectrum to be registered and the band range of the second spectrum to be registered according to the result of the matching calculation, until a first spectral range of the first channel and a second spectral range of the second channel that matches the first spectral range are obtained; the matching calculation includes calculating the value of the normalized correlation function of the first spectrum to be registered and the second spectrum to be registered, and calculating the matching degree of the peaks and troughs of the first spectrum to be registered and the second spectrum to be registered.

[0103] In one embodiment, the registration module 44 is specifically used for:

[0104] If the first spectrum to be registered and the second spectrum to be registered are successfully matched, the width of the band of the first spectrum to be registered is expanded until the matching quality of the expanded first spectrum to be registered and the expanded second spectrum to be registered is less than a first set value. The first spectral range is determined based on the expanded first spectrum to be registered, and the second spectral range is determined based on the expanded second spectrum to be registered. The successful matching includes the value of the normalized correlation function being less than a first threshold and the matching degree being greater than a second threshold.

[0105] If the first spectrum to be registered fails to match the second spectrum to be registered, and there is no band in the second interference spectrum that successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is reduced until the matching quality of the reduced first spectrum to be registered and the reduced second spectrum to be registered is greater than a second set value. The first spectral range is determined based on the reduced first spectrum to be registered, and the second spectral range is determined based on the reduced second spectrum to be registered.

[0106] In one embodiment, the registration module 44 is specifically used for:

[0107] If the first spectrum to be registered fails to match the second spectrum to be registered, then the band range of the second spectrum to be registered is adjusted.

[0108] If the adjusted second spectrum to be registered successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is expanded.

[0109] If the adjusted second registration spectrum fails to match the first registration spectrum, it is determined that there is no band in the second interference spectrum that successfully matches the first registration spectrum.

[0110] In one embodiment, the matching degree is determined based on the number of troughs in the second spectrum to be registered that correspond to the peaks of the first spectrum to be registered, and the number of peaks in the second spectrum to be registered that correspond to the troughs of the first spectrum to be registered.

[0111] In one embodiment, the registration module 44 is specifically used for:

[0112] If the first spectrum to be registered successfully matches the second spectrum to be registered, and the third spectrum to be registered in the first channel and the fourth spectrum to be registered in the second channel are successfully matched after adjusting the distance of the mirror, then the width of the band of the first spectrum to be registered is expanded.

[0113] In one embodiment, the registration module 44 is specifically used for:

[0114] Both the first and second spectra to be registered are converted into the correspondence between wavelength and signal intensity under the condition of uniform wavenumber distribution;

[0115] Matching calculations are performed on the first and second spectra to be registered after conversion.

[0116] In one embodiment, the registration module 44 is specifically used for:

[0117] Construct an equally spaced first wavenumber sequence based on the start and end wavelengths of the first spectrum to be registered;

[0118] Based on the first wavenumber sequence and the corresponding signal intensity, the correspondence between the wavelength and signal intensity of the first spectrum to be registered under the condition of uniform wavenumber distribution is obtained;

[0119] A second wavenumber sequence with equal spacing is constructed based on the start wavelength and end wavelength of the second spectrum to be registered, wherein the spacing of the first wavenumber sequence is the same as the spacing of the second wavenumber sequence;

[0120] Based on the second wavenumber sequence and the corresponding signal intensity, the correspondence between the wavelength and signal intensity of the second spectrum to be registered under the condition of uniform wavenumber distribution is obtained.

[0121] In one embodiment, the registration module 44 is further configured to:

[0122] Acquire the first detection signal of the first channel and the second detection signal of the second channel obtained by scanning the sample with the OCT device;

[0123] The detection information of the sample is determined based on the difference between the first detection signal in the first spectral range and the second detection signal in the second spectral range.

[0124] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0125] The spectral registration method provided in this application is executed by an electronic device. This application also provides a spectral registration system, including an OCT device, a reflector, and the aforementioned electronic device.

[0126] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may be a desktop computer, laptop, handheld computer, or cloud server, etc.

[0127] like Figure 5 As shown, the electronic device in this embodiment includes: a processor 11, a memory 12, and a computer program 13 stored in the memory 12 and executable on the processor 11. When the processor 11 executes the computer program 13, it implements the steps in the above-described spectral registration method embodiment, for example... Figure 2 Steps S201 to S204 are shown. Alternatively, when the processor 11 executes the computer program 13, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of the acquisition module 41 to the registration module 44 are shown.

[0128] For example, the computer program 13 may be divided into one or more modules / units, which are stored in the memory 12 and executed by the processor 11 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 13 in the electronic device.

[0129] Those skilled in the art will understand that Figure 5 This is merely an example of an electronic device and does not constitute a limitation on the electronic device. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, etc.

[0130] The processor 11 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0131] The memory 12 can be an internal storage unit of the electronic device, such as a hard drive or RAM. The memory 12 can also be an external storage device of the electronic device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 12 can include both internal and external storage units. The memory 12 is used to store the computer program and other programs and data required by the electronic device. The memory 12 can also be used to temporarily store data that has been output or will be output.

[0132] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0133] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0134] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0135] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0136] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0137] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0138] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0139] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A spectral registration method, characterized in that, include: The first interference spectrum and the second interference spectrum obtained by scanning the reflector of the OCT device are acquired. The first interference spectrum is received through the first channel and the second interference spectrum is received through the second channel. The phase difference between the first interference spectrum and the second interference spectrum is 180°. Select the first spectrum to be registered from the first interference spectrum; A second spectrum to be registered is selected from the second interference spectrum, wherein the width of the band of the second spectrum to be registered is the same as the width of the band of the first spectrum to be registered. Matching calculations are performed on the first and second spectra to be registered. Based on the results of the matching calculations, the band ranges of the first and second spectra to be registered are adjusted until a first spectral range for the first channel and a second spectral range for the second channel that matches the first spectral range are obtained. The matching calculations include calculating the normalized correlation function values ​​of the first and second spectra to be registered, and calculating the matching degree of the peaks and troughs of the first and second spectra to be registered. Both the first and second spectra to be registered represent the correspondence between wavelength and signal intensity. The matching calculations are performed on the first and second spectra to be registered. The matching calculation includes: constructing a first wavenumber sequence with equal spacing based on the start and end wavelengths of the first spectrum to be registered; obtaining the correspondence between wavelength and signal intensity of the first spectrum to be registered under a uniform wavenumber distribution based on the first wavenumber sequence and the corresponding signal intensity; constructing a second wavenumber sequence with equal spacing based on the start and end wavelengths of the second spectrum to be registered, wherein the spacing of the first wavenumber sequence and the second wavenumber sequence are the same; obtaining the correspondence between wavelength and signal intensity of the second spectrum to be registered under a uniform wavenumber distribution based on the second wavenumber sequence and the corresponding signal intensity; performing matching calculations on the converted first spectrum to be registered and the converted second spectrum to be registered; according to the formula... Calculate the values ​​of the normalized correlation functions for the first and second spectra to be registered, where, This represents the signal intensity corresponding to each wavelength in the first spectrum to be registered. The normalized correlation function represents the signal intensity corresponding to each wavelength in the second spectrum to be registered, μ_A represents the mean signal intensity of the first spectrum to be registered, μ_B represents the mean signal intensity of the second spectrum to be registered, σ_A represents the standard deviation of the signal intensity of the first spectrum to be registered, and σ_B represents the standard deviation of the signal intensity of the second spectrum to be registered. When the first spectrum to be registered and the second spectrum to be registered are completely oppositely aligned, the value of the normalized correlation function is -1; when the first spectrum to be registered and the second spectrum to be registered are completely identical, the value of the normalized correlation function is 1.

2. The spectral registration method according to claim 1, characterized in that, Based on the results of the matching calculation, adjust the band ranges of the first and second spectra to be registered until a first spectral range of the first channel and a second spectral range of the second channel that matches the first spectral range are obtained, including: If the first spectrum to be registered and the second spectrum to be registered are successfully matched, the width of the band of the first spectrum to be registered is expanded until the matching quality of the expanded first spectrum to be registered and the expanded second spectrum to be registered is less than a first set value. The first spectral range is determined based on the expanded first spectrum to be registered, and the second spectral range is determined based on the expanded second spectrum to be registered. The successful matching includes the value of the normalized correlation function being less than a first threshold and the matching degree being greater than a second threshold. If the first spectrum to be registered fails to match the second spectrum to be registered, and there is no band in the second interference spectrum that successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is reduced until the matching quality of the reduced first spectrum to be registered and the reduced second spectrum to be registered is greater than a second set value. The first spectral range is determined based on the reduced first spectrum to be registered, and the second spectral range is determined based on the reduced second spectrum to be registered.

3. The spectral registration method according to claim 2, characterized in that, The method further includes: If the first spectrum to be registered fails to match the second spectrum to be registered, then the band range of the second spectrum to be registered is adjusted. If the adjusted second spectrum to be registered successfully matches the first spectrum to be registered, then the width of the band of the first spectrum to be registered is expanded. If the adjusted second registration spectrum fails to match the first registration spectrum, it is determined that there is no band in the second interference spectrum that successfully matches the first registration spectrum.

4. The spectral registration method according to claim 2, characterized in that, The matching degree is determined based on the number of valleys in the second spectrum to be registered that correspond to the peaks in the first spectrum to be registered, and the number of peaks in the second spectrum to be registered that correspond to the valleys in the first spectrum to be registered.

5. The spectral registration method according to claim 2, characterized in that, If the first spectrum to be registered successfully matches the second spectrum to be registered, then the bandwidth of the first spectrum to be registered is expanded, including: If the first spectrum to be registered successfully matches the second spectrum to be registered, and the third spectrum to be registered in the first channel and the fourth spectrum to be registered in the second channel are successfully matched after adjusting the distance of the mirror, then the width of the band of the first spectrum to be registered is expanded.

6. The spectral registration method according to claim 1, characterized in that, After obtaining the first spectral range of the first channel and the second spectral range of the second channel that matches the first spectral range, the method further includes: Acquire the first detection signal of the first channel and the second detection signal of the second channel obtained by scanning the sample with the OCT device; The detection information of the sample is determined based on the difference between the first detection signal in the first spectral range and the second detection signal in the second spectral range.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 6.

8. A spectral registration system, comprising an OCT device, a mirror, and the electronic device as claimed in claim 7.

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