Method for enhancing microfossils by micro-nano energy spectrum CT scanning
By using micro-nano energy spectroscopy CT technology and iodine compound solution staining, the problem of obtaining the three-dimensional structure of microfossils has been solved, and efficient and non-destructive three-dimensional structure reconstruction and species identification have been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INST OF VERTEBRATE PALEONTOLOGY & PALEOANTHROPOLOGY CHINESE ACAD OF SCI
- Filing Date
- 2023-08-21
- Publication Date
- 2026-06-30
AI Technical Summary
Current technology makes it difficult to effectively obtain high-contrast CT images and three-dimensional structures of microfossils, making it difficult for paleontologists to accurately identify genus and species relationships.
By employing micro-nano energy spectroscopy CT technology combined with iodine compound solution impregnation and image domain material decomposition processing, high-contrast three-dimensional structural images were obtained by purifying microfossils and separating the iodine compound solution from the microfossils during CT scanning.
This method enables efficient and non-destructive three-dimensional structural reconstruction of microfossils, improving the accuracy and efficiency of microfossil species identification.
Smart Images
Figure CN117110333B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of micro-nano energy spectrum CT enhanced scanning technology, specifically a method for micro-nano energy spectrum CT enhanced scanning of micro fossils. Background Technology
[0002] Microfossils are tiny remains or traces of ancient organisms preserved in strata and not visible to the naked eye. The wealth of geological information contained within microfossils is of paramount importance for research in earth sciences, life sciences, and environmental sciences. In recent years, thanks to the widespread use of micro-CT technology in micropaleontology, paleontologists can obtain more comprehensive three-dimensional data of microfossils non-destructively through micro-CT scans, including the three-dimensional microstructure from the interior to the surface of the microfossil. However, microfossils are usually encased in dense, massive, high-calcium surrounding rocks, resulting in significant background noise in the CT images, making it impossible to accurately discern the external outline of the microfossil. The internal cavities of microfossils are also often filled by the surrounding rock, affecting the contrast of the CT images and similarly hindering the accurate identification of the cavity boundaries. These phenomena all impede paleontologists' ability to reconstruct the internal and external three-dimensional structure of microfossils, thus affecting their identification of the genera and species. The identification of genera and species of microfossils is of great research value and practical significance for exploring the origin and evolution of early life and for finding and determining the location of oil-bearing strata in strata.
[0003] Traditional paleotectonic sectioning can also be used to obtain the internal and external microstructures of microfossils. To prepare microfossil sections, they are typically embedded in a matrix (such as epoxy resin or paraffin) to prevent deformation during slicing. A hard tissue microtome is then used to cut the embedded microfossils into thin sections. Images of the microfossil sections are then obtained by observing them under an optical microscope or scanning electron microscope, allowing for the extraction of the internal and external contour information of the microfossils for species identification.
[0004] Traditional microfossil imaging methods suffer from the following problems and drawbacks: While fossil slicing methods can acquire images of the internal and external structures of microfossils, they can only obtain two-dimensional information at specific locations and angles, failing to acquire submicron-level continuous slices, and thus cannot fully reconstruct the three-dimensional structure of the microfossils. Furthermore, these methods require significant manpower and resources for a series of procedures, including microfossil embedding and slicing. Moreover, this method is destructive, and paleotissue slicing is unsuitable for particularly valuable microfossils. Because microfossils are filled or encased by dense surrounding rock, conventional micro-CT techniques struggle to obtain high-contrast CT images of microfossils with research and practical value. Paleontologists cannot accurately distinguish the internal and external contours of microfossils from CT images obtained through conventional micro-CT, greatly hindering subsequent semantic segmentation and three-dimensional reconstruction of the microfossil CT images, and affecting the identification of the genus and species of microfossils. Summary of the Invention
[0005] To overcome the shortcomings of conventional micro-CT and traditional slicing methods in acquiring three-dimensional image contour information of the internal and external parts of microfossils, this invention provides a method for micro-nano energy spectral CT-enhanced scanning of microfossils, which can efficiently and non-destructively acquire high-contrast CT images of microfossils and clearly display the three-dimensional structure of the internal and external parts of microfossils.
[0006] The technical solution of the present invention includes:
[0007] A method for micro / nano energy spectral CT-enhanced scanning of microfossils, the method comprising:
[0008] A rock sample containing microfossils is purified to obtain pure microfossils; wherein the rock sample includes: surrounding rock and pure microfossils embedded in the surrounding rock;
[0009] The pure microfossils were placed in a sample container containing an iodine compound solution to stain them. Then, a CT scanning container was made using two pipette tips. The CT scanning container contained the stained pure microfossils and the iodine compound solution, and it was ensured that the stained pure microfossils and the iodine compound solution were separated and had a clear air interface.
[0010] Micro-nano energy dispersive CT was used to perform CT scanning and data processing on a CT scanning container containing pure microfossils after iodine contamination and iodine compound solution. High-energy and low-energy tomographic data of the iodine compound solution and pure microfossils after iodine contamination were obtained. The thresholds of the low-energy and high-energy regions were obtained based on the K-edge characteristics of iodine.
[0011] After performing image domain material decomposition processing on the high-energy region fault map data and the low-energy region fault map data respectively, the image domain processing results are fused to obtain the three-dimensional structure of the inside and outside of the pure microfossil.
[0012] Furthermore, the rock sample containing microfossils is purified to obtain pure microfossils, including:
[0013] Use a geological hammer to break the rock sample containing microfossils into smaller pieces;
[0014] Small rock samples were soaked in an acidic solution.
[0015] After the acid treatment reaction is completed, the solid mixture that was not dissolved by the acidic solution is retained; wherein the acidic solution in the solid mixture is replaced by pure water;
[0016] The solid mixture that was not dissolved by the acidic solution was screened to obtain a fine-particle solid mixture containing microfossils and undissolved minerals;
[0017] After drying the fine-particle solid mixture, an alkaline substance and deionized water are added and the mixture is boiled to obtain a mixture of microfossils, mud and fine impurities.
[0018] After filtering the mud and fine impurities from the mixture of microfossils, mud, and fine impurities, pure microfossils suitable for research are selected from the microfossils.
[0019] Further, the solid mixture that was not dissolved by the acidic solution is screened to obtain a fine-particle solid mixture containing microfossils and undissolved minerals, including:
[0020] The solid mixture is passed through a fine-mesh sieve to obtain a coarse-particle solid mixture;
[0021] The coarse-grained solid mixture is passed through a medium-mesh sieve to obtain a medium-grained solid mixture;
[0022] The medium-sized solid mixture is passed through a large-mesh sieve to obtain a fine-particle mixture containing microfossils and undissolved minerals.
[0023] Further, filtering the mud and fine impurities from the mixture of microfossils, mud, and fine impurities includes:
[0024] The mixture of microfossils, mud, and fine impurities is placed in a container and rinsed under a slow stream of water.
[0025] Once the water in the container is no longer cloudy, the remaining solid mixture in the container is passed through an extra-large mesh sieve to obtain a mixture containing microfossils and fine impurities.
[0026] After drying the mixture containing microfossils and fine impurities, it is placed in a separatory funnel, and a heavy liquid is added to the separatory funnel so that the heavy liquid can separate the microfossils and fine impurities by utilizing the density difference between the microfossils and fine impurities.
[0027] The heavy liquid containing fine impurities is discharged, and the heavy liquid containing microfossils is filtered and dried to obtain the microfossils.
[0028] Furthermore, pure microfossils suitable for research are selected from the said microfossils, including:
[0029] After laying the microfossils flat into long strips, select the microfossils that can be used for research under a stereomicroscope;
[0030] Microfossils are identified based on their morphological characteristics that can be used for research, resulting in pure microfossils; wherein, the morphological characteristics include: outline and aspect ratio.
[0031] Furthermore, the acidic solution includes a 3%-7% acetic acid solution.
[0032] Furthermore, the alkaline substance includes: baking soda.
[0033] Furthermore, the iodine compound solution includes: potassium iodide solution.
[0034] Furthermore, the fabrication of a CT scanning container using two pipette tips includes:
[0035] The purified microfossil is placed in a first pipette tip; wherein the model of the first pipette tip is based on the diameter of the purified microfossil, and the first pipette tip includes: a suction end and a large-diameter end;
[0036] Cut off the middle of the aspiration end of the second pipette tip, and vertically insert the aspiration end of the first pipette tip containing the pure microfossils into the cut part of the second pipette tip; wherein, the second pipette tip is the same model as the first pipette tip;
[0037] The large-diameter end of the second pipette tip is fitted onto a glass rod; wherein the diameter of the glass rod is smaller than the diameter of the large-diameter end of the second pipette tip.
[0038] The joint between the first pipette tip and the second pipette tip, and the joint between the second pipette tip and the glass rod, were sealed using liquid hot melt adhesive.
[0039] Add the iodine compound solution from the large-diameter end of the first pipette tip, ensuring that the pure microfossils are separated from the iodine compound solution and that there is a clear air interface.
[0040] Furthermore, micro-nano energy dispersive CT was used to perform CT scanning and data processing on a CT scanning container containing the impregnated pure microfossils and iodine compound solution, obtaining high-energy and low-energy tomographic data containing the iodine compound solution and the impregnated pure microfossils, including:
[0041] Micro-nano energy-dispersive CT was used to perform CT scanning on a CT scanning container containing pure microfossils after staining and iodine compound solution, and high-energy and low-energy projection images of the iodine compound solution and pure microfossils after staining were obtained.
[0042] The GPU-accelerated FDK algorithm is used to convert the high-energy region projection map and the low-energy region projection map into high-energy region fault map data and low-energy region fault map data, respectively.
[0043] Compared with the prior art, the present invention has the following advantages:
[0044] 1) Edible alkali was selected in the microfossil purification method, which can further dissolve the fine-particle solid mixture, so that the adhering substances on the surface of the microfossil are transformed into mud, which can ensure that the patterns on the surface of the microfossil are fully exposed.
[0045] 2) A CT scanning container was made during the sample preparation of microfossils. It can not only use the gravity of the microfossils themselves to stably hold them in the pipette tip, thus meeting the requirements of micro-nano energy spectrum CT enhanced scanning of microfossils and avoiding the generation of image artifacts and noise, but also ensure that the microfossils are separated from the iodine compound solution and have a clear air interface, thus meeting the material decomposition requirements of micro-nano energy spectrum CT.
[0046] 3) The application of micro-nano energy spectral CT technology to enhance the contrast of CT images of microfossils has enabled the identification and reconstruction of microfossils and their internal three-dimensional structures, helping paleontologists to identify the genus and species relationships of microfossils more efficiently and accurately;
[0047] 4) The more refined energy information provided by photon counting spectral CT imaging technology can effectively reduce image noise and improve imaging efficiency during microfossil CT imaging, thereby obtaining higher quality microfossil CT images. Attached Figure Description
[0048] Figure 1 This is a flowchart illustrating the process of micro-nano energy spectral CT enhanced scanning of microfossils provided in an embodiment of the present invention.
[0049] Figure 2 This is a flowchart illustrating the purification of microfossils provided in an embodiment of the present invention.
[0050] Figure 3 This is a schematic diagram of microfossil staining and sample preparation provided in an embodiment of the present invention.
[0051] Figure 4 This is a flowchart illustrating the acquisition and post-processing of microfossil CT images provided in an embodiment of the present invention. Detailed Implementation
[0052] To make the objectives, solutions, and advantages of this invention clearer, the invention will be further described in detail using experiments conducted on real fish microfossils as an example. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.
[0053] A method for micro / nano energy spectral CT-enhanced scanning of microfossils, the method comprising:
[0054] A geological hammer is used to break large limestone samples rich in microfossils collected in the field into smaller pieces. The surrounding rock of the microfossils is mainly composed of carbonates, while the microfossils themselves are mainly composed of phosphates. This invention uses a diluted formic acid or acetic acid solution to soak the small sample pieces in a beaker until the acid treatment reaction is complete and no more bubbles are produced. The supernatant in the beaker is poured off, retaining the solid mixture that has not been dissolved by the diluted acetic acid. The remaining diluted acetic acid in the solid mixture is then replaced with a slow-flowing stream of water.
[0055] After the diluted acetic acid in the solid mixture has been completely replaced, microfossils are screened from the remaining solid mixture using sieves of different mesh sizes. First, a coarse-grained solid mixture is obtained by passing it through a small-mesh sieve, then a medium-mesh sieve is obtained, and finally, a mixture of microfossils and undissolved fine mineral particles is obtained by passing it through a large-mesh sieve.
[0056] The microfossils were almost entirely concentrated in a fine-particle solid mixture, which was then dried in an oven. The dried mixture was then poured into a large beaker containing deionized water, and baking soda was added. The mixture was heated to boiling to remove as many impurities as possible from the surface of the microfossils.
[0057] The boiled mixture of fine-particle solids was then rinsed under a slow stream of water into a beaker until the water in the beaker was no longer cloudy. The mixture was then filtered through an extra-large mesh sieve to remove the slurry, and the resulting mixture of microfossils and fine impurities was dried again. This mixture of microfossils and fine impurities was then dried in an oven.
[0058] The dried mixture of microfossils and fine impurities is poured into a separatory funnel, while a heavy liquid is added simultaneously. The microfossils are then separated using the density difference between the heavy liquid and the microfossils. After separation, the heavy liquid containing the microfossils flows downwards out of the separatory funnel. After filtration through filter paper, the microfossils remain on the filter paper, while the heavy liquid is retained in a beaker. The heavy liquid can be reused multiple times, and it can be recovered after the microfossils have been separated.
[0059] The microfossils on the filter paper were rinsed with a slow stream of water into a beaker, then dried again. The microfossils were then dried in an oven. The dried microfossils were laid flat in long strips, and those suitable for research were selected under a stereomicroscope. The selected microfossils were identified, classified, and preserved based on their morphological characteristics, such as outlines and aspect ratios.
[0060] Next, the selected microfossils to be scanned by micro-nano energy dispersive CT were immersed in an iodine compound solution in test tubes to stain them. The microfossils were then removed from the iodine compound solution and placed in a first pipette tip. The type of pipette tip selected depended on the diameter of the microfossil to be scanned.
[0061] A socket is made by cutting off the middle of the aspiration end of a second pipette tip of the same model. The aspiration end of the first pipette tip containing the microfossils is then vertically inserted into the socket. The socket is sealed with heated liquid hot melt adhesive to ensure a good seal between the first pipette tip and the socket.
[0062] The larger end of the second pipette tip is fitted onto a glass rod with a diameter smaller than the tip's own. The area around the larger end of the second pipette tip is sealed with heated liquid hot melt adhesive to ensure a good seal between the larger end of the second pipette tip and the glass rod.
[0063] A small amount of iodine compound solution is placed into the wide end of the first pipette tip containing the microfossils, ensuring that the microfossils are separated from the iodine compound solution and that there is a clear air interface. To ensure that the microfossils can be stably held in the first pipette tip by their own gravity, the entire sample container set should be placed vertically on a test tube rack.
[0064] After the microfossils stabilized in the first pipette tip, the sample container containing the iodine compound solution and the microfossils was placed on the micro-nano energy-dispersive CT air-bearing turntable. Two sets of projection image data from different energy regions (high and low) were acquired using micro-nano energy-dispersive CT data acquisition software to ensure that the scanning field of view included both the iodine compound solution and the intact microfossils. This invention, based on the K-edge characteristic image of iodine, selects low and high energy thresholds to improve the ability of micro-nano energy-dispersive CT to identify iodine.
[0065] This invention utilizes micro-nano energy spectrum CT reconstruction software to reconstruct two sets of projection map data from high and low energy regions, obtaining two sets of tomographic data in different energy regions, ensuring that the tomographic data includes iodine compound solution and microfossils. The invention employs a GPU-accelerated FDK algorithm to convert the acquired microfossil projection map data into microfossil tomographic data.
[0066] Using the EnergySpectrumAnalysis material decomposition module of the micro-nano energy spectrum CT post-processing software, two sets of tomographic data in different energy ranges were simultaneously selected: Matrix material 1 (iodine compound solution) and matrix material 2 (microfossils). The material decomposition post-processing algorithm, specifically the image domain material decomposition algorithm, was then used to decompose the energy spectrum CT images of the microfossils, obtaining continuous tomographic data for both matrix material 1 (iodine compound solution) and matrix material 2 (microfossils).
[0067] By employing a post-processing algorithm based on material decomposition, the base material 1 (iodine compound solution) retained within the internal cavity of the microfossil can be separated, thus enabling the automatic acquisition of the three-dimensional structure of the internal cavity of the microfossil. Similarly, the base material 2 (microfossil) can be separated using the same post-processing algorithm, allowing the automatic acquisition of the three-dimensional structure of the microfossil. This invention achieves the identification and three-dimensional reconstruction of microfossils and their internal cavities by setting multiple energy thresholds on the photon counting detector of a micro-nano energy spectrum CT scanner, thereby acquiring projection map data from multiple energy regions in a single imaging session. These data are perfectly matched in time and space. Furthermore, this invention utilizes an image-domain material decomposition algorithm to fuse two sets of microfossil tomographic data from different energy regions (high and low), realizing the identification and three-dimensional reconstruction of microfossils and their internal cavities.
[0068] In one embodiment, the present invention uses micro-nano energy spectrum CT to enhance the scanning of fish microfossils, including the steps of: purifying microfossils, staining microfossil samples, scanning microfossils with micro-nano energy spectrum CT, and decomposing the material in the CT images of microfossils.
[0069] Specifically, such as Figure 1 As shown, the present invention includes the following steps:
[0070] Step 1: Purify microfossils.
[0071] This invention uses a series of physicochemical methods to purify fish microfossils embedded in surrounding rocks, thereby enabling the identification, classification, and preservation of these microfossils. Figure 2 As shown.
[0072] In one example, a large marl rock sample rich in fish microfossils was collected from the Early Devonian Xitun Formation in Qujing, Yunnan, China. This sample was then broken into small cubic samples with sides approximately 5 cm using a geological hammer. The surrounding rock of these fish microfossils was primarily composed of carbonates, while the fish microfossils themselves were primarily composed of phosphates. In this example, the small cubic samples were soaked in a diluted acetic acid solution (3%-7%) in a beaker for at least two weeks until the acid treatment reaction ceased and no more bubbles were produced. The supernatant was then poured off, leaving the undissolved solid mixture. The remaining diluted acetic acid in the solid mixture was then replaced with a slow-flowing stream of water for approximately 12 hours.
[0073] After the diluted acetic acid in the solid mixture has been completely replaced, fish microfossils are screened from the remaining solid mixture using sieves of different pore sizes (sieve pore size: 100 micrometers-600 micrometers). First, a coarse-grained solid mixture is obtained by passing it through a 30-mesh sieve (sieve pore size: 600 micrometers), then a medium-grained solid mixture is obtained by passing it through an 80-mesh sieve (sieve pore size: 180 micrometers), and finally a mixture of fish microfossils and undissolved fine mineral particles is obtained by passing it through a 100-mesh sieve (sieve pore size: 150 micrometers).
[0074] The fish microfossils were almost entirely concentrated in a fine-particle solid mixture. This mixture was dried in an oven for approximately 8 hours at a temperature of 40-60°C. The dried mixture was then poured into a large beaker, and baking soda (a mixture of soda ash (Na₂CO₃) and sodium bicarbonate (NaHCO₃)) was added. The mixture was then boiled with deionized water for 30 minutes. After boiling, the fine impurities attached to the fish microfossils dissolved into a slurry. This process allows for more thorough separation of the fish microfossils from the surrounding rock, removing as many impurities as possible from the fine-particle solid mixture.
[0075] The boiled mixture of fine-particle solids was placed under a slow stream of water into a beaker until the water in the beaker was no longer cloudy. The mixture was then filtered through a 150-mesh sieve (100 micrometers aperture) to remove the slurry. The resulting mixture of fish microfossils and fine impurities was dried again. This mixture was then oven-dried for 8 hours at a temperature of 40-60℃.
[0076] The dried mixture of fish microfossils and fine impurities is poured into a separatory funnel, and lithium polytungstate (LST) is added as a heavy liquid. The fish microfossils are then separated for 1-2 hours. The lithium polytungstate solution separates the fish microfossils and fine impurities based on their density difference. After separation, the lithium polytungstate solution containing the fish microfossils flows downwards out of the separatory funnel. After filtration through filter paper, the fish microfossils remain on the filter paper, while the lithium polytungstate solution is retained in the beaker. The lithium polytungstate solution can be reused multiple times, and it can be recovered after the fish microfossils are separated.
[0077] Fish microfossils on filter paper were rinsed into a beaker with a slow stream of water and dried again after 24 hours. The microfossils were then dried in an oven at 40-60℃ for 8 hours. The dried microfossils were laid flat in long strips, and suitable fossils were selected for research under a stereomicroscope at magnifications of 20-80x. The selected microfossils were identified, classified, and preserved based on their morphological characteristics, such as outlines and aspect ratios. These microfossils were relatively well-preserved (e.g., *Yang's fish*, *Scoidea*, placoderms, and spiny fish).
[0078] Step 2: Infiltration and preparation of microfossil samples.
[0079] This invention employs a staining method to treat purified fish microfossils, enhancing the three-dimensional structure of internal cavities such as medullary pores. This invention also develops a sample preparation container for fish microfossils to ensure their stability during the acquisition of projection image data using micro / nano energy dispersive spectroscopy (EDS) imaging. Figure 3 As shown, this embodiment of the invention provides a container for preparing fish microfossil samples. 1 is a glass rod, 2 is a second pipette tip (socket), 3 is the microfossil, 4 is potassium iodide solution, and 5 is a first pipette tip.
[0080] Fish microfossils selected for micro / nano energy dispersive spectroscopy (EDS) CT scanning were soaked in a 1% potassium iodide solution in test tubes for 2-3 days. The microfossils were then removed from the potassium iodide solution and placed in a first pipette tip. The type of pipette tip selected depended on the diameter (approximately 3 mm) of the fish microfossils to be scanned. In this invention, a 10 μL pipette tip (5 mm diameter) was selected for holding fish microfossils selected through a 150-mesh sieve.
[0081] Cut a 1.5cm section from the aspiration end of a second pipette tip of the same model to create a socket. Vertically insert the aspiration end of the first pipette tip containing the fish microfossils into the socket. Seal the socket with heated liquid hot melt adhesive. To ensure the stability of the first pipette tip, apply 2-3 coats of hot melt adhesive to ensure a good seal between the first pipette tip and the socket.
[0082] This invention uses a 10ul (5mm diameter) pipette tip. The larger diameter end of the second pipette tip is fitted onto a 4mm diameter glass rod (8cm high). The larger diameter end of the second pipette tip is sealed with heated liquid hot melt adhesive. To ensure the stability of the second pipette tip, 2-3 coats of hot melt adhesive can be applied to ensure a good seal between the larger diameter end of the second pipette tip and the glass rod.
[0083] Add approximately 5 μL of potassium iodide solution to the wide end of the first pipette tip containing the fish microfossils, ensuring that the fish microfossils are separated from the potassium iodide solution and that there is a clear air boundary. To ensure that the fish microfossils remain stably attached to the first pipette tip due to their own gravity, the entire sample container should be placed vertically on a test tube rack for 24 hours.
[0084] Step 3: Micro-nano energy spectroscopy CT scan of microfossils.
[0085] This invention improves the ability of micro-nano energy spectroscopy to identify iodine by selecting high and low energy thresholds based on the K-edge feature image of iodine.
[0086] After the microfossils stabilized in the first pipette tip, the sample container containing potassium iodide solution and fish microfossils was placed on the micro-nano energy-dispersive CT air-bearing turntable. Two sets of projection image data from different energy regions (high and low) were acquired using micro-nano energy-dispersive CT data acquisition software to ensure that the scanning field of view included both the potassium iodide solution and the intact fish microfossils. This invention, based on the K-edge characteristic image of iodine, selects 15kV as the low-energy threshold and 33kV as the high-energy threshold to improve the micro-nano energy-dispersive CT's ability to identify iodine. The micro-nano energy-dispersive CT model is SNCT-800, and the scanning conditions are as follows: voxel size 2 μm, frame rate 1 Hz, number of superimposed frames 2, number of projection images per 360° 1440, voltage 100 kV, and current 150 μA.
[0087] Two sets of tomographic images in different energy ranges (high and low) were reconstructed using micro-nano energy spectrum CT reconstruction software to obtain two sets of tomographic images, ensuring that the tomographic images included potassium iodide solution and fish microfossils. This invention employs a GPU-accelerated FDK algorithm, which can convert 1,440 acquired projection images into 512 2048×2048 pixel tomographic images.
[0088] Step 4: Material decomposition of microfossils in CT images.
[0089] This invention employs a post-processing algorithm for material decomposition, namely an image-domain material decomposition algorithm, which can directly obtain the internal and external three-dimensional structure of fish microfossils, such as... Figure 4As shown in the embodiment of the present invention, micro-nano energy spectroscopy CT scans fish microfossils and the process of material decomposition are presented.
[0090] Using the EnergySpectrumAnalysis material decomposition module of the micro-nano energy spectrum CT post-processing software, two sets of tomographic data in different energy ranges were simultaneously selected: substrate 1 (potassium iodide solution) and substrate 2 (fish microfossils). The image domain material decomposition algorithm was then used to decompose the energy spectrum CT images of the fish microfossils, obtaining continuous tomographic data for both substrate 1 (potassium iodide solution) and substrate 2 (fish microfossils).
[0091] By employing a post-processing algorithm for material decomposition, the potassium iodide solution (base material 1) retained within the internal cavities of fish microfossils can be separated. This invention can then automatically obtain the three-dimensional structure of internal cavities such as medullary pores within fish microfossils. Similarly, by employing the same post-processing algorithm, the base material (base material 2) can be separated from the fish microfossils. This invention can then automatically obtain the three-dimensional structure of fish microfossils, such as their ornamentation.
[0092] In summary, current traditional techniques cannot provide submicron-level continuous slices and high-contrast CT images of microfossils, failing to meet the needs of paleontologists for accurate identification of genus and species relationships in microfossils. This invention achieves automated imaging of the internal and external three-dimensional microstructure of microfossils through a series of processes, including purification of microfossils, staining of microfossil samples, micro-nano energy-spectrum CT scanning of microfossils, and final material decomposition of the CT images of microfossils. The micro-nano energy-spectrum CT-enhanced scanning method for microfossils developed in this invention has significant research value and practical implications for exploring the origin and evolution of early life and for locating and determining the position of oil-bearing strata in geological formations.
[0093] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for micro / nano energy-spectral CT-enhanced scanning of microfossils, characterized in that, The method includes: A rock sample containing microfossils is purified to obtain pure microfossils; wherein the rock sample includes: surrounding rock and pure microfossils embedded in the surrounding rock; The pure microfossils were placed in a sample container containing an iodine compound solution to stain them. Then, a CT scanning container was made using two pipette tips. The CT scanning container contained the stained pure microfossils and the iodine compound solution, and it was ensured that the stained pure microfossils and the iodine compound solution were separated and had a clear air interface. Micro-nano energy dispersive CT was used to perform CT scanning and data processing on a CT scanning container containing pure microfossils after iodine contamination and iodine compound solution. High-energy and low-energy tomographic data of the iodine compound solution and pure microfossils after iodine contamination were obtained. The thresholds of the low-energy and high-energy regions were obtained based on the K-edge characteristics of iodine. After performing image domain material decomposition processing on the high-energy region fault map data and the low-energy region fault map data respectively, the image domain processing results are fused to obtain the three-dimensional structure of the inside and outside of the pure microfossil. The method of fabricating a CT scanning container using two pipette tips includes: The purified microfossil is placed in a first pipette tip; wherein the model of the first pipette tip is based on the diameter of the purified microfossil, and the first pipette tip includes: a suction end and a large-diameter end; Cut off the middle of the aspiration end of the second pipette tip, and vertically insert the aspiration end of the first pipette tip containing the pure microfossils into the cut part of the second pipette tip; wherein, the second pipette tip is the same model as the first pipette tip; The large-diameter end of the second pipette tip is fitted onto a glass rod; wherein the diameter of the glass rod is smaller than the diameter of the large-diameter end of the second pipette tip. The joint between the first pipette tip and the second pipette tip, and the joint between the second pipette tip and the glass rod, were sealed using liquid hot melt adhesive. Add the iodine compound solution from the large-diameter end of the first pipette tip, ensuring that the pure microfossils are separated from the iodine compound solution and that there is a clear air interface.
2. The method as described in claim 1, characterized in that, The purification process of rock samples containing microfossils to obtain pure microfossils includes: Use a geological hammer to break the rock sample containing microfossils into smaller pieces; Small rock samples were soaked in an acidic solution. After the acid treatment reaction is completed, the solid mixture that was not dissolved by the acidic solution is retained; wherein the acidic solution in the solid mixture is replaced by pure water; The solid mixture that was not dissolved by the acidic solution was screened to obtain a fine-particle solid mixture containing microfossils and undissolved minerals; After drying the fine-particle solid mixture, an alkaline substance and deionized water are added and the mixture is boiled to obtain a mixture of microfossils, mud and fine impurities. After filtering the mud and fine impurities from the mixture of microfossils, mud, and fine impurities, pure microfossils suitable for research are selected from the microfossils. The process of filtering the mixture of microfossils, mud, and fine impurities includes: The mixture of microfossils, mud, and fine impurities is placed in a container and rinsed under a slow stream of water. Once the water in the container is no longer cloudy, the remaining solid mixture in the container is passed through an extra-large mesh sieve to obtain a mixture containing microfossils and fine impurities. After drying the mixture containing microfossils and fine impurities, it is placed in a separatory funnel, and a heavy liquid is added to the separatory funnel so that the heavy liquid can separate the microfossils and fine impurities by utilizing the density difference between the microfossils and fine impurities. The heavy liquid containing fine impurities is discharged, and the heavy liquid containing microfossils is filtered and dried to obtain the microfossils.
3. The method as described in claim 2, characterized in that, The solid mixture that was not dissolved by the acidic solution was screened to obtain a fine-particle solid mixture containing microfossils and undissolved minerals, comprising: The solid mixture is passed through a fine-mesh sieve to obtain a coarse-particle solid mixture; The coarse-grained solid mixture is passed through a medium-mesh sieve to obtain a medium-grained solid mixture; The medium-sized solid mixture is passed through a large-mesh sieve to obtain a fine-particle mixture containing microfossils and undissolved minerals.
4. The method as described in claim 2, characterized in that, Pure microfossils suitable for research were selected from the aforementioned microfossils, including: After laying the microfossils flat into long strips, select the microfossils that can be used for research under a stereomicroscope; Microfossils are identified based on the morphological characteristics of the microfossils that can be used for research, and pure microfossils are obtained; wherein, the morphological characteristics include: outline and aspect ratio.
5. The method as described in claim 2, characterized in that, The acidic solution includes a 3%-7% acetic acid solution.
6. The method as described in claim 2, characterized in that, The alkaline substance includes: baking soda.
7. The method as described in claim 1, characterized in that, The iodine compound solution includes: potassium iodide solution.
8. The method as described in claim 1, characterized in that, Micro-nano energy dispersive CT was used to perform CT scans and data processing on a CT scanning container containing impregnated pure microfossils and an iodine compound solution. This yielded high-energy and low-energy tomographic data of both the iodine compound solution and the impregnated pure microfossils, including: Micro-nano energy-dispersive CT was used to perform CT scanning on a CT scanning container containing pure microfossils after staining and iodine compound solution, and high-energy and low-energy projection images of the iodine compound solution and pure microfossils after staining were obtained. The GPU-accelerated FDK algorithm is used to convert the high-energy region projection map and the low-energy region projection map into high-energy region fault map data and low-energy region fault map data, respectively.