Spectrometer for expanding the imaging depth of OCT and fusion imaging method

Abstract

The application belongs to the technical field of optical coherence tomography, and particularly relates to a spectrometer for expanding the imaging depth of OCT and a fusion imaging method. The spectrometer comprises a dichroic mirror, which is used for receiving incident light entering the spectrometer and separating the incident light into first exit light and second exit light; a first photosensitive element, which is placed at a position where the first exit light with wavelengths in a first range is imaged, and is used for imaging the first exit light with wavelengths in the first range; and a second photosensitive element, which is placed at a position where the second exit light with wavelengths in a second range is imaged, and is used for imaging the second exit light with wavelengths in the second range. The number of equivalent pixels obtained by the application is greater than the number of pixels of a single camera, so that the OCT brings higher spectral resolution and realizes greater imaging depth under the condition that the spectral range is unchanged.

Description

Technical Field

[0001] This invention belongs to the field of optical coherence tomography (OCT) technology, and particularly relates to spectrometers and fusion imaging methods for expanding the depth of OCT imaging. Background Technology

[0002] In OCT detection, the imaging depth is related to the transmittance of the analyte and the detectable frequency of the spectrometer. The detectable frequency of the spectrometer is affected by the spectral resolution of the detector; the higher the spectral resolution, the higher the detectable frequency of the spectrometer, and consequently, the greater the detectable depth of the OCT. Given a fixed spectral range, the spectral resolution of the spectrometer is only related to the number of pixels in the camera. Simply using a camera with a high pixel count will limit the transmission speed, affecting the system's scanning speed. Furthermore, in current technologies, the number of pixels in cameras is fixed; without cameras with a larger pixel count, the spectral resolution of the spectrometer cannot be improved.

[0003] Existing technologies include those that use multiple cameras to receive spectra, such as the Chinese invention patent entitled "A High-Resolution Skip-Type Multi-Band Spectrometer and Its Working Method." While this technology improves image resolution and OCT imaging depth, it cannot achieve continuous spectral acquisition. Spectral discontinuity will cause sidelobe noise in the processed OCT image, affecting the imaging effect. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention provides a spectrometer and fusion imaging method for expanding the imaging depth of OCT. The incident light is split by a dichroic mirror to obtain a first emitted light and a second emitted light. A first photosensitive element is placed at the position where the first emitted light with a wavelength in a first range is imaged, and a second photosensitive element is placed at the position where the second emitted light with a wavelength in a second range is imaged. This results in a partial overlap between the first range of wavelengths of the first emitted light and the second range of wavelengths of the second emitted light. The resulting equivalent number of pixels is greater than the number of pixels of a single camera, enabling OCT to achieve higher spectral resolution and greater imaging depth while maintaining the same spectral range.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the present invention provides a spectrometer for extending the depth of OCT imaging.

[0007] A spectrometer for extending the depth of OCT imaging includes a dichroic mirror, a first photosensitive element, and a second photosensitive element.

[0008] A dichroic mirror is used to receive incident light entering the spectrometer and split the incident light into a first outgoing light and a second outgoing light.

[0009] A first photosensitive element is placed at the position where the first emitted light with a wavelength within a first range is imaged, and is used to image the first emitted light with a wavelength within the first range;

[0010] The second photosensitive element is placed at the position where the second emitted light with a wavelength within the second range is imaged, and is used to image the second emitted light with a wavelength within the second range.

[0011] As an alternative technical solution, the first emitted light images the first photosensitive element along the first optical path, and the second emitted light images the second photosensitive element along the second optical path.

[0012] As an optional technical solution, it also includes a first grating and a first lens disposed on the first optical path, wherein:

[0013] The first grating is used to receive the first outgoing light and diffract the first outgoing light to form the diffracted light of the first outgoing light;

[0014] A first lens is used to receive the diffracted light of the first outgoing light and to image the diffracted light of the first outgoing light onto a first photosensitive element.

[0015] As an alternative technical solution, a second grating and a second lens are also provided on the second optical path, wherein:

[0016] The second grating is used to receive the second outgoing light and diffract the second outgoing light to form the diffracted light of the second outgoing light;

[0017] The second lens is used to receive the diffracted light of the second outgoing light and to image the diffracted light of the second outgoing light onto the second photosensitive element.

[0018] As an alternative technical solution, the first grating and the second grating have the same structure.

[0019] As an alternative technical solution, a first incident angle is formed between the first emitted light and the first grating, and a second incident angle is formed between the second emitted light and the second grating, wherein the first incident angle and the second incident angle are the same.

[0020] As an alternative technical solution, the first emitted light and the second emitted light are parallel lights.

[0021] As an alternative technical solution, the first range of the first emitted light wavelength and the second range of the second emitted light wavelength partially overlap.

[0022] As an alternative technical solution, the first photosensitive element and the second photosensitive element have a partially overlapping region in the receiving wavelength range in the spectral direction.

[0023] As an alternative technical solution, the first photosensitive element and the second photosensitive element form an optical conjugate:

[0024] The image planes corresponding to the first and second photosensitive elements are located at equivalent imaging plane positions and have consistent imaging rules.

[0025] The first and second photosensitive elements receive spectral images of different wavelength ranges, wherein within the overlapping bands covered by the two photosensitive elements, the imaging positions of the same wavelength components on the two image planes have a definite correspondence.

[0026] The second aspect of the present invention provides a fusion imaging method for a spectrometer that extends the imaging depth of OCT.

[0027] A fusion imaging method for spectrometers that extends the imaging depth of OCT includes the following steps:

[0028] The first and second photosensitive elements in the spectrometer for expanding the OCT imaging depth described in the first aspect are registered;

[0029] Obtain the corresponding wavelength information of each pixel on the first and second photosensitive elements after registration of the light source to be imaged;

[0030] Spectral data of the first photosensitive element and the second photosensitive element in the wavelength overlap region and the wavelength non-overlap region are acquired respectively, and then continuous spectral data are obtained;

[0031] Fusion imaging was achieved based on continuous spectral data.

[0032] As an optional technical solution, spectral data of the first photosensitive element and the second photosensitive element in the wavelength overlap region and the wavelength non-overlap region are acquired respectively, thereby obtaining continuous spectral data, specifically including:

[0033] In the wavelength overlap region, the fused data of the spectral intensities collected by the first photosensitive element and the second photosensitive element are calculated as the fused spectral data of the wavelength overlap region;

[0034] Within the non-overlapping wavelength range, the spectral data corresponding to the first and second photosensitive elements are directly used as independent spectral data;

[0035] By combining fused spectral data from overlapping wavelength regions with independent spectral data from non-overlapping wavelength regions, continuous spectral data is obtained.

[0036] As an alternative technical solution, weighted average fusion, signal-to-noise ratio-based weighted fusion, or optimization fusion based on the minimum error criterion are used to calculate the fused spectral data in the wavelength overlap region.

[0037] As an alternative technical solution, the registration of the first photosensitive element and the second photosensitive element specifically includes:

[0038] Obtain the original spectrum and the shaped spectrum of the light source;

[0039] The original spectrum and the shaped spectrum are sequentially input into a spectrometer that expands the depth of OCT imaging to obtain the wavelength corresponding to each pixel;

[0040] An evaluation coefficient is constructed based on the wavelength corresponding to each pixel.

[0041] Adjust the positions of the first and second photosensitive elements, and cyclically calculate the evaluation coefficients until the set stopping conditions are met, thereby achieving registration of the first and second photosensitive elements.

[0042] As an optional technical solution, after acquiring the corresponding wavelength information of each pixel on the first and second photosensitive elements after registration of the light source to be imaged, the method further includes:

[0043] The spectral data of the light source to be imaged, collected by the first and second photosensitive elements, are mapped to a unified wavelength coordinate system to form wavelength-intensity data pairs.

[0044] Based on the receiving wavelength ranges of the first and second photosensitive elements, the overlapping wavelength ranges of the two are determined, and the wavelength overlapping range and the wavelength non-overlapping range are divided.

[0045] The above one or more technical solutions have the following beneficial effects:

[0046] This invention provides a spectrometer and fusion imaging method for expanding the imaging depth of OCT. The incident light is split by a dichroic mirror to obtain a first outgoing light and a second outgoing light. A first photosensitive element is placed at the position where the first outgoing light with a wavelength within a first range is imaged, and a second photosensitive element is placed at the position where the second outgoing light with a wavelength within a second range is imaged. The resulting equivalent number of pixels is greater than the number of pixels in a single camera, enabling OCT to achieve higher spectral resolution while maintaining the same spectral range. In the same spectral range, more pixels can be achieved, thereby achieving a greater imaging depth.

[0047] In the wavelength overlap region, this invention calculates the fused spectral intensity data collected by the first and second photosensitive elements as the fused spectral data for the wavelength overlap region; in the wavelength non-overlap region, the corresponding spectral data of the first and second photosensitive elements are directly used as independent spectral data; by combining the fused spectral data of the wavelength overlap region and the independent spectral data of the wavelength non-overlap region, continuous spectral data is obtained, thereby ensuring the continuous distribution of the spectrum throughout the entire working wavelength band, achieving higher density spectral sampling without changing the spectral range, and providing a basis for improving spectral resolution and imaging depth.

[0048] This invention uses multiple cameras to simultaneously acquire imaging information, and the data transmission does not interfere with each other.

[0049] The present invention acquires a continuous spectrum, and subsequent signal processing will not generate sidelobe noise.

[0050] This invention can achieve camera pixel matching in physical space without interpolation processing.

[0051] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0052] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0053] Figure 1 This is a structural diagram of a spectrometer in the existing technology.

[0054] Figure 2 The diagram shows the structure of the spectrometer provided in Example 1.

[0055] Figure 3 The images show the spectral information collected by the first and second photosensitive elements in Example 1.

[0056] Figure 4 This is a schematic diagram of the transmissivity and reflectivity of the dichroic mirror in Example 1.

[0057] Figure 5 This is the spectral information diagram after fusion in Example 2.

[0058] The attached diagram lists the components represented by each number as follows:

[0059] 1. Incident light; 2. Original grating; 3. Original lens; 4. Original photosensitive element; 5. Dichroic mirror; 6. First outgoing light; 7. Second outgoing light; 8. First grating; 9. Second grating; 10. First lens; 11. Second lens; 12. First photosensitive element; 13. Second photosensitive element. Detailed Implementation

[0060] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0061] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0062] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0063] Example 1

[0064] Figure 1 The diagram shows a spectrometer structure in the prior art. To distinguish it from the spectrometer structure designed in this embodiment below, the components of the spectrometer structure in the prior art are named the original grating 2, the original lens 3, and the original photosensitive element 4. Figure 1 In the process, incident light 1 enters the original grating 2 at a set incident angle. The original grating 2 performs diffraction and beam splitting on the incident light 1. The resulting diffracted light is then projected onto the original photosensitive element 4 through the original lens 3 to form an image.

[0065] In the setting of the grating of the transmission grating spectrometer ,in The wavelength of the emitted light is represented by λ, the width of the grating slit is d, and the angle of incidence of the beam is α. Let be the angle at which light exits the grating corresponding to the wavelength. Let the angle between the lens axis and the grating normal be . The wavelength of the emitted light at this angle is , considered as the center angular wavelength of the spectrometer, falls on the first angular wavelength of the photosensitive element. In terms of pixels, express The pixel position where the light falls.

[0066] The distance between the position where light of different wavelengths falls on the photosensitive element and the center position. for:

[0067] ,

[0068] in, This indicates the focal length of the original lens 3.

[0069] Let the pixel width of the photosensitive element be... Let the first Pixel center distance The focal distance is denoted as 'a' (a is negative if the focal point is on the shorter wavelength side of the pixel, and positive if it is on the longer wavelength side), where... Indicates the first If there are 10 pixels, then the center of the i-th pixel is 100 pixels away from the center of the i-th pixel. focal distance for:

[0070] ,

[0071] Then the wavelength corresponding to the center of the i-th pixel for:

[0072] .

[0073] Let N be the theoretical number of pixels for the spectrometer, then:

[0074] ,

[0075] in, express The distance between the position of the wavelength of light falling on the photosensitive element and the center position. express The distance between the position of the wavelength of light falling on the photosensitive element and the center position. express The angle at which the wavelength of light exits the grating. express The angle at which the wavelength of light exits the grating.

[0076] With other parameters remaining constant, a larger f value theoretically allows for a higher pixel count in the spectrometer. However, the pixel count of existing cameras is fixed and cannot be increased indefinitely.

[0077] Based on this, this embodiment designs a novel spectrometer structure that expands the depth of OCT imaging, which can theoretically accommodate an infinite number of pixels without requiring interpolation compensation.

[0078] like Figure 2 As shown, the spectrometer for expanding the depth of OCT imaging includes a dichroic mirror 5, a first photosensitive element 12, and a second photosensitive element 13.

[0079] Dichroic mirror 5 is used to receive incident light 1 entering the spectrometer and split the incident light 1 into first outgoing light 6 and second outgoing light 7.

[0080] The first photosensitive element 12 is placed at the position where the first emitted light 6 with a wavelength in the first range is imaged, and is used to image the first emitted light 6 with a wavelength in the first range.

[0081] The second photosensitive element 13 is placed at the position where the second emitted light 7 with a wavelength in the second range is imaged, and is used to image the second emitted light 7 with a wavelength in the second range.

[0082] It can be understood that, in this embodiment, after the incident light 1 is emitted by the light source and enters the spectrometer, it first undergoes spectral splitting by the dichroic mirror 5. The dichroic mirror 5 splits the incident light 1 into a first outgoing light 6 and a second outgoing light 7. The first outgoing light 6 propagates along the first optical path and eventually reaches the first photosensitive element 12 for imaging. The second outgoing light 7 propagates along the second optical path and eventually reaches the second photosensitive element 13 for imaging.

[0083] In this embodiment, the first photosensitive element 12 is placed at the position imaged by the first emitted light 6 with a wavelength in the first range, while the second photosensitive element 13 is placed at the position imaged by the second emitted light 7 with a wavelength in the second range. The first range of the wavelength of the first emitted light and the second range of the wavelength of the second emitted light partially overlap, so that more pixels can be achieved under the same spectral range.

[0084] In practical implementation, assuming the existence of an ideal photosensitive element with N pixels, capable of completely covering the entire spectral range of the spectrometer, the corresponding theoretical wavelength sequence is as follows: When the theoretical number of pixels N is greater than the number of pixels n of a single photosensitive element, a single photosensitive element cannot cover the entire spectral range, thus requiring multiple photosensitive elements for reception. An intuitive approach is to arrange two photosensitive elements sequentially along the spectral direction, with one covering the short-wavelength region and the other covering the long-wavelength region. However, in actual spectrometer structures, photosensitive elements have certain physical dimensions, making it difficult to achieve seamless splicing of two photosensitive elements at the focal plane, which can easily lead to structural interference or installation difficulties.

[0085] In this embodiment, the incident light 1 is split into two parallel beams by a dichroic mirror 5. The two parallel beams are incident at the same angle on gratings with the same structure (i.e., the first grating 8 and the second grating 9). By maintaining consistency, two independent spectral image planes are formed on different optical paths. In this structure, the first photosensitive element 12 is used to receive short-wavelength spectra, and the second photosensitive element 13 is used to receive long-wavelength spectra. Short-wavelength light is received by the first photosensitive element 12, and long-wavelength light is received by the second photosensitive element 13. The two photosensitive elements form an optical conjugate and have a partially overlapping region in the received wavelength range along the spectral direction. This results in an equivalent number of pixels greater than the number of pixels in a single camera, enabling OCT to achieve higher spectral resolution while maintaining the same spectral range. It also allows for a greater number of pixels within the same spectral range, thus achieving greater imaging depth.

[0086] The two photosensitive elements form an optical conjugate, which specifically means:

[0087] The image planes formed by the first emitted light 6 and the second emitted light 7 after passing through their respective optical systems are optically conjugate, meaning that the image planes corresponding to the two light beams are at equivalent imaging plane positions and have consistent imaging rules. The first photosensitive element 12 and the second photosensitive element 13 are respectively disposed at different positions on the image plane to receive spectral images of different wavelength ranges. Within the overlapping wavelength bands covered by the two photosensitive elements, the imaging positions of the same wavelength components on the two image planes have a definite correspondence.

[0088] In this embodiment, the two photosensitive elements have a partially overlapping area, specifically:

[0089] The receiving wavelength ranges of the first photosensitive element 12 and the second photosensitive element 13 in the spectral direction are not completely non-overlapping. Instead, a common wavelength range is set at the boundary, meaning that spectral images within a certain wavelength range can simultaneously fall within the effective imaging areas of both the first photosensitive element 12 and the second photosensitive element 13. The imaging area corresponding to this commonly covered wavelength range is the partially overlapping area of ​​the two photosensitive elements, used to ensure that the two spectra have common reference information at the boundary, thereby avoiding coverage gaps at the band intersection.

[0090] More specifically, such as Figure 2 As shown, a first grating 8 and a first lens 10 are arranged in the first optical path, and a second grating 9 and a second lens 11 are arranged in the second optical path. The first emitted light 6 passes through the first grating 8 and the first lens 10 and then reaches the first photosensitive element 12 for imaging. The second emitted light 7 passes through the second grating 9 and the second lens 11 and then reaches the second photosensitive element 13 for imaging. The first grating 8 and the second grating 9 have identical structures.

[0091] It can be understood that the functions of the first grating 8 and the first lens 10 are:

[0092] The first grating 8 is used to receive the first outgoing light 6 and diffract the first outgoing light 6 to form the diffracted light of the first outgoing light 6;

[0093] The first lens 10 is used to receive the diffracted light of the first outgoing light 6 and to image the diffracted light of the first outgoing light 6 onto the first photosensitive element 12.

[0094] It can be understood that the functions of the second grating 9 and the second lens 11 are:

[0095] The second grating 9 is used to receive the second emitted light 7 and diffract the second emitted light 7 to form the diffracted light of the second emitted light 7;

[0096] The second lens 11 is used to receive the diffracted light of the second outgoing light 7 and to image the diffracted light of the second outgoing light 7 onto the second photosensitive element 13.

[0097] In the first and second optical path propagation paths described above, a first incident angle is formed between the first emitted light 6 and the first grating 8, and a second incident angle is formed between the second emitted light 7 and the second grating 9. The first incident angle and the second incident angle are the same.

[0098] like Figure 3 The image shows spectral information collected by the first photosensitive element 12 and the second photosensitive element 13 in this embodiment. The horizontal axis represents wavelength, the vertical axis represents spectral intensity, the solid line represents the spectral information collected by the first photosensitive element 12, and the dashed line represents the spectral information collected by the second photosensitive element 13. Figure 3 As can be seen from this, the first photosensitive element 12 mainly receives and images short-wavelength spectral information, corresponding to a wavelength range of... to The second photosensitive element 13 mainly receives and images long-wavelength spectral information, corresponding to a wavelength range of... to ; and in to Within the wavelength range, the two photosensitive elements share common coverage of spectral information, thus forming partially overlapping bands.

[0099] in, This indicates the wavelength received at the center position of the first pixel of the first photosensitive element 12. This represents the wavelength received at the center position of the nth pixel of the first photosensitive element 12. This indicates the wavelength received at the center position of the first pixel of the second photosensitive element 13. This represents the wavelength received at the center position of the nth pixel of the second photosensitive element 13, where N represents the theoretical number of pixels of the spectrometer.

[0100] Going further:

[0101] Assuming dichroic mirror 5 can transmit wavelengths shorter than 5, The reflected wavelength is greater than Light, partially transmitted and partially reflected and The light in the middle, then:

[0102] when , At that time, both the first and second photosensitive elements can receive... arrive The light, but it will cause arrive as well as arrive Light in this band incurs additional losses;

[0103] when , At that time, the first photosensitive element 12 can still receive arrive The light is received, but the second photosensitive element 13 does not receive it. arrive The light at this time will only cause arrive Light in this band incurs additional losses;

[0104] when , At that time, the second photosensitive element 13 can still receive arrive The light, but the first photosensitive element 12 cannot receive it. arrive The light at this time will only cause arrive Light in this band incurs additional losses;

[0105] when At that time, the first photosensitive element 12 cannot receive [the signal]. arrive The second photosensitive element 13 cannot receive the light. arrive The light does not incur any additional loss;

[0106] in, This indicates the wavelength at which the transmittance of dichroic mirror 5 begins to decrease significantly. This indicates the wavelength critical point at which the reflectivity of dichroic mirror 5 reaches a stable high reflectivity state; and The wavelength between these wavelengths is the spectral transition band of the dichroic mirror 5, in which both transmittance and reflectance exist simultaneously, and light energy is partially transmitted and partially reflected.

[0107] In the above process, light incurs additional losses, which specifically means:

[0108] Since the transmission and reflection characteristics of the dichroic mirror 5 in its spectral transition band are not ideal (either fully transparent or fully reflective), when the wavelength of the incident light 1 is in this transition band, some light energy is not fully received by either the first or second light path, thus failing to effectively reach the corresponding photosensitive element for imaging. This manifests as a reduction in spectral intensity in this band, which is the additional loss of light.

[0109] The registration of the two photosensitive elements (first photosensitive element 12 and second photosensitive element 13) mentioned above specifically refers to:

[0110] Within the overlapping spectral bands, a definite one-to-one correspondence is established between the imaging positions of the same wavelength on two photosensitive elements. When the overlapping bands are too narrow, the common reference information is insufficient, making it difficult to reliably establish this correspondence and making registration even more challenging.

[0111] Figure 4 This is a schematic diagram of the transmissivity and reflectivity of the dichroic mirror 5 in this embodiment. Figure 4 In the diagram, the horizontal axis represents wavelength, and the vertical axis represents percentage. The solid line curve represents the reflectance of dichroic mirror 5, and the dashed line curve represents the transmittance of dichroic mirror 5. A line representing 100% is also shown, represented by a dashed line parallel to the x-axis. It can be seen that on the horizontal axis... At position 5, the transmittance of the dichroic mirror begins to decrease significantly, while the reflectance begins to gradually increase; on the horizontal axis... At position 5, the reflectivity of the dichroic mirror reaches its highest value, and the transmittance reaches its lowest value.

[0112] Example 2

[0113] This embodiment discloses a fusion imaging method for a spectrometer that expands the imaging depth of OCT.

[0114] A fusion imaging method for spectrometers that extends the imaging depth of OCT includes the following steps:

[0115] The first and second photosensitive elements in the spectrometer for expanding OCT imaging depth described in Example 1 are registered;

[0116] Obtain the corresponding wavelength information of each pixel on the first and second photosensitive elements after registration of the light source to be imaged;

[0117] Spectral data of the first photosensitive element and the second photosensitive element in the wavelength overlap region and the wavelength non-overlap region are acquired respectively, and then continuous spectral data are obtained;

[0118] Fusion imaging was achieved based on continuous spectral data.

[0119] Furthermore, spectral data of the first and second photosensitive elements in the overlapping and non-overlapping wavelength regions are acquired respectively to obtain continuous spectral data, specifically including:

[0120] In the wavelength overlap region, the fused data of the spectral intensities collected by the first photosensitive element and the second photosensitive element are calculated as the fused spectral data of the wavelength overlap region;

[0121] Within the non-overlapping wavelength range, the spectral data corresponding to the first and second photosensitive elements are directly used as independent spectral data;

[0122] By combining fused spectral data from overlapping wavelength regions with independent spectral data from non-overlapping wavelength regions, continuous spectral data is obtained.

[0123] More specifically, fusion imaging includes the following steps:

[0124] (1) Establish a unified wavelength coordinate system:

[0125] The spectral data of the light source to be imaged, collected by the first and second photosensitive elements, are mapped to a unified wavelength coordinate system to form corresponding wavelength-intensity data pairs.

[0126] (2) Determine the splicing interval:

[0127] Based on the receiving wavelength ranges of the first and second photosensitive elements, the overlapping wavelength ranges of the two are determined, and the wavelength overlapping range and the wavelength non-overlapping range are divided.

[0128] (3) Data fusion in overlapping areas:

[0129] Within the wavelength overlap region, the spectral intensities acquired by two photosensitive elements are fused. The fusion method includes weighted average fusion, signal-to-noise ratio-based weighted fusion, or optimization fusion based on the minimum error criterion.

[0130] The weighting coefficients can be determined based on the response sensitivity or noise level of the two photosensitive elements in that band.

[0131] (4) Forming a continuous spectral sequence:

[0132] Within the non-overlapping wavelength range, independent spectral data are obtained by directly using the spectral data of the corresponding photosensitive element;

[0133] Within the wavelength overlap region, the spectral data of the first and second photosensitive elements after fusion is calculated to obtain the fused spectral data.

[0134] Based on independent spectral data and fused spectral data, a continuously distributed spectral sequence, i.e., continuous spectral data, is constructed within the entire working band.

[0135] (5) Used for OCT imaging reconstruction:

[0136] By performing k-space linearization and Fourier transform on continuous spectral data, depth-direction reflection information is reconstructed, thereby completing fusion imaging.

[0137] Furthermore, the registration of the first and second photosensitive elements specifically includes:

[0138] Obtain the original spectrum and the shaped spectrum of the light source;

[0139] The original spectrum and the shaped spectrum are sequentially input into a spectrometer that expands the depth of OCT imaging to obtain the wavelength corresponding to each pixel;

[0140] An evaluation coefficient is constructed based on the wavelength corresponding to each pixel.

[0141] Adjust the positions of the first and second photosensitive elements, and cyclically calculate the evaluation coefficients until the set stopping conditions are met, thereby achieving registration of the first and second photosensitive elements.

[0142] In practice, the registration process includes:

[0143] (1) First, make the input light of the spectrometer as follows: and ,in, The original spectrum of the light source, The spectrum produced after the light source has been shaped. The shaping factor; The spectral intensity represents the original spectrum. This represents the spectral intensity of the spectrum produced after shaping. This indicates the acquisition of the spectral intensity corresponding to the input light.

[0144] (2) The spectrometer receives the light signals twice and calculates... The shaping coefficients for each pixel of the first and second photosensitive elements are obtained. and This allows us to obtain the wavelength corresponding to each pixel of the first and second photosensitive elements. and Where i1 represents the pixel position of the first photosensitive element and i2 represents the pixel position of the second photosensitive element; This indicates the wavelength corresponding to pixel i1 of the first photosensitive element; This indicates the wavelength corresponding to pixel i2 of the second photosensitive element.

[0145] (3) Calculate the evaluation coefficient Where n represents the number of pixels of the photosensitive element and N represents the theoretical number of pixels of the spectrometer; then the position of the photosensitive element is adjusted on the focal plane of the lens, and the evaluation coefficient is calculated again. This process is repeated multiple times until the value of the evaluation coefficient is approximately 0.

[0146] Standard deviation can also be used. Used as an evaluation coefficient Indicates the second photosensitive element The wavelength corresponding to the pixel. At this point, the minimum evaluation coefficient indicates that the two photosensitive elements have achieved registration.

[0147] like Figure 5 The image shows the fused spectral information, where the horizontal axis represents wavelength and the vertical axis represents spectral intensity. Within the wavelength overlap region between the first and second photosensitive elements, the fused spectral intensity data acquired by the first and second photosensitive elements was calculated and used as the fused spectral data for the wavelength overlap region.

[0148] from Figure 5 As can be seen, the fused spectrum maintains a continuous distribution throughout the entire working band, indicating that through the coordinated reception of multiple photosensitive elements, higher density spectral sampling can be achieved without changing the spectral range, providing a basis for improving spectral resolution and imaging depth.

[0149] The dual photosensitive element is only a specific example. This embodiment can also be extended to the structure and registration of spectrometers with multiple photosensitive elements.

[0150] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0151] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A spectrometer for expanding the depth of OCT imaging, characterized in that, Includes a dichroic mirror, a first photosensitive element, and a second photosensitive element: A dichroic mirror is used to receive incident light entering the spectrometer and split the incident light into a first outgoing light and a second outgoing light. A first photosensitive element is placed at the position where the first emitted light with a wavelength within a first range is imaged, and is used to image the first emitted light with a wavelength within the first range; The second photosensitive element is placed at the position where the second emitted light with a wavelength in the second range is imaged, and is used to image the second emitted light with a wavelength in the second range. The first range of the first emitted light wavelength and the second range of the second emitted light wavelength partially overlap; The first photosensitive element and the second photosensitive element form an optical conjugate.

2. The spectrometer for extending OCT imaging depth as described in claim 1, characterized in that, The first emitted light images the first photosensitive element along the first optical path, and the second emitted light images the second photosensitive element along the second optical path.

3. The spectrometer for extending OCT imaging depth as described in claim 2, characterized in that, It also includes a first grating and a first lens disposed on the first optical path, wherein: The first grating is used to receive the first outgoing light and diffract the first outgoing light to form the diffracted light of the first outgoing light; A first lens is used to receive the diffracted light of the first outgoing light and to image the diffracted light of the first outgoing light onto a first photosensitive element.

4. The spectrometer for extending OCT imaging depth as described in claim 3, characterized in that, It also includes a second grating and a second lens disposed on the second optical path, wherein: The second grating is used to receive the second outgoing light and diffract the second outgoing light to form the diffracted light of the second outgoing light; The second lens is used to receive the diffracted light of the second outgoing light and to image the diffracted light of the second outgoing light onto the second photosensitive element.

5. The spectrometer for extending OCT imaging depth as described in claim 4, characterized in that, The first grating and the second grating have the same structure.

6. The spectrometer for extending OCT imaging depth as described in claim 4, characterized in that, The first emitted light and the first grating form a first incident angle, and the second emitted light and the second grating form a second incident angle, wherein the first incident angle and the second incident angle are the same.

7. The spectrometer for extending OCT imaging depth as described in claim 1, characterized in that, The first emitted light and the second emitted light are parallel lights.

8. The spectrometer for extending OCT imaging depth as described in claim 1, characterized in that, The first photosensitive element and the second photosensitive element have a partially overlapping region in the receiving wavelength range along the spectral direction.

9. The spectrometer for extending OCT imaging depth as described in claim 1, characterized in that: The image planes corresponding to the first and second photosensitive elements are located at equivalent imaging plane positions and have consistent imaging rules. The first and second photosensitive elements receive spectral images of different wavelength ranges, wherein within the overlapping bands covered by the two photosensitive elements, the imaging positions of the same wavelength components on the two image planes have a definite correspondence.

10. A fusion imaging method for spectrometers that extends the imaging depth of OCT, characterized in that, Includes the following steps: Register the first and second photosensitive elements in the spectrometer for expanding OCT imaging depth as described in any one of claims 1-9; Obtain the corresponding wavelength information of each pixel on the first and second photosensitive elements after registration of the light source to be imaged; Spectral data of the first photosensitive element and the second photosensitive element in the wavelength overlap region and the wavelength non-overlap region are acquired respectively, and then continuous spectral data are obtained; Fusion imaging was achieved based on continuous spectral data.

11. The fusion imaging method for a spectrometer that extends the imaging depth of OCT as described in claim 10, characterized in that, Spectral data of the first and second photosensitive elements in the overlapping and non-overlapping wavelength regions are acquired respectively to obtain continuous spectral data, specifically including: In the wavelength overlap region, the fused data of the spectral intensities collected by the first photosensitive element and the second photosensitive element are calculated as the fused spectral data of the wavelength overlap region; Within the non-overlapping wavelength range, the spectral data corresponding to the first and second photosensitive elements are directly used as independent spectral data; By combining fused spectral data from overlapping wavelength regions with independent spectral data from non-overlapping wavelength regions, continuous spectral data is obtained.

12. The fusion imaging method for a spectrometer that extends the imaging depth of OCT as described in claim 11, characterized in that, We calculate the fused spectral data in the wavelength overlap region by employing weighted average fusion, signal-to-noise ratio-based weighted fusion, or optimized fusion based on the minimum error criterion.

13. The fusion imaging method for a spectrometer that extends the imaging depth of OCT as described in claim 10, characterized in that, The registration of the first and second photosensitive elements specifically includes: Obtain the original spectrum and the shaped spectrum of the light source; The original spectrum and the shaped spectrum are sequentially input into a spectrometer that expands the depth of OCT imaging to obtain the wavelength corresponding to each pixel; An evaluation coefficient is constructed based on the wavelength corresponding to each pixel. Adjust the positions of the first and second photosensitive elements, and cyclically calculate the evaluation coefficients until the set stopping conditions are met, thereby achieving registration of the first and second photosensitive elements.

14. The fusion imaging method for a spectrometer that extends the imaging depth of OCT as described in claim 13, characterized in that, After acquiring the corresponding wavelength information of each pixel on the registered first and second photosensitive elements of the light source to be imaged, the process also includes: The spectral data of the light source to be imaged, collected by the first and second photosensitive elements, are mapped to a unified wavelength coordinate system to form wavelength-intensity data pairs. Based on the receiving wavelength ranges of the first and second photosensitive elements, the overlapping wavelength ranges of the two are determined, and the wavelength overlapping range and the wavelength non-overlapping range are divided.

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