CN113012151B - OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system - Google Patents
OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system Download PDFInfo
- Publication number
- CN113012151B CN113012151B CN202110454010.2A CN202110454010A CN113012151B CN 113012151 B CN113012151 B CN 113012151B CN 202110454010 A CN202110454010 A CN 202110454010A CN 113012151 B CN113012151 B CN 113012151B
- Authority
- CN
- China
- Prior art keywords
- region
- datum point
- oct
- point
- area
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000003702 image correction Methods 0.000 title claims abstract description 19
- 238000012014 optical coherence tomography Methods 0.000 title description 103
- 238000012937 correction Methods 0.000 claims abstract description 12
- 230000005484 gravity Effects 0.000 claims description 6
- 230000011218 segmentation Effects 0.000 claims description 6
- 238000013519 translation Methods 0.000 claims description 6
- 238000004458 analytical method Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 3
- 238000000605 extraction Methods 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 11
- 230000000007 visual effect Effects 0.000 abstract description 4
- 210000001519 tissue Anatomy 0.000 description 28
- 238000003384 imaging method Methods 0.000 description 10
- 210000003128 head Anatomy 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 206010052428 Wound Diseases 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005311 autocorrelation function Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 210000003161 choroid Anatomy 0.000 description 1
- 210000004087 cornea Anatomy 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 239000010437 gem Substances 0.000 description 1
- 229910001751 gemstone Inorganic materials 0.000 description 1
- 210000000554 iris Anatomy 0.000 description 1
- 238000002372 labelling Methods 0.000 description 1
- 230000003902 lesion Effects 0.000 description 1
- 238000012821 model calculation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 210000001525 retina Anatomy 0.000 description 1
- 230000002207 retinal effect Effects 0.000 description 1
- 210000003583 retinal pigment epithelium Anatomy 0.000 description 1
- 210000003786 sclera Anatomy 0.000 description 1
- 238000001356 surgical procedure Methods 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
- 210000001585 trabecular meshwork Anatomy 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0012—Biomedical image inspection
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/10—Segmentation; Edge detection
- G06T7/187—Segmentation; Edge detection involving region growing; involving region merging; involving connected component labelling
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/25—Determination of region of interest [ROI] or a volume of interest [VOI]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10072—Tomographic images
- G06T2207/10101—Optical tomography; Optical coherence tomography [OCT]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/20—Special algorithmic details
- G06T2207/20092—Interactive image processing based on input by user
- G06T2207/20104—Interactive definition of region of interest [ROI]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/24—Aligning, centring, orientation detection or correction of the image
- G06V10/247—Aligning, centring, orientation detection or correction of the image by affine transforms, e.g. correction due to perspective effects; Quadrilaterals, e.g. trapezoids
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Multimedia (AREA)
- Computer Vision & Pattern Recognition (AREA)
- General Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Quality & Reliability (AREA)
- Health & Medical Sciences (AREA)
- Image Processing (AREA)
Abstract
The invention discloses an OCT image correction method and system for an SS-OCT operation navigation system, which comprises the following steps: 1) For the distorted OCT image, dividing a target area in the OCT image into three parts according to the relative positions of a scalpel and a tissue structure, and marking the three parts as an area I, an area II and an area III; 2) Correcting the vertical distortion of the area I; 3) Correcting the distortion of the area II; 4) Region iii was used as a reference, and an OCT image after correction was obtained without treatment. According to the invention, the reference points are arranged according to the position relation between the surgical knife and the tissue structure in the operation, the reference points are used for dividing the OCT image, and then the distortion correction is carried out pertinently according to the characteristics of each region, so that the image distortion caused by refraction and scattering effects in the operation process is effectively eliminated, the OCT image is more visual and vivid, and great convenience is brought to the positioning of focus, the observation of adjacent tissues and the implementation of the operation.
Description
Technical Field
The invention relates to the field, in particular to an OCT image correction method and system for an SS-OCT operation navigation system.
Background
The optical coherence tomography (Optical coherence tomography, OCT) is used as a non-contact tomography, has the characteristics of high resolution, high sensitivity and the like, and is widely applied to medical imaging. At present, OCT technology is used for ophthalmic imaging, which can not only display macroscopic structures such as cornea, iris, sclera, etc., but also provide images of microscopic structures such as trabecular meshwork, visual cross tube, schlemm's tube, etc., and has become an important auxiliary means in diagnosis and treatment of ophthalmic diseases. According to the OCT two-dimensional image acquired before operation, a doctor can plan an operation path, judge tissue lesions, navigate in real time operation and evaluate operation effects, and operation time is shortened while operation wounds are reduced. OCT technology has become an integral part of the navigation of ophthalmic surgery. With the development of high-speed sweep-frequency optical coherence tomography (Swept source optical coherence tomography, SS-OCT), the axial scanning speed of OCT reaches hundreds of kHz, and simultaneously the imaging depth and sensitivity of OCT are greatly improved, so that real-time imaging of faults and surgical instruments in human tissues in the surgical process is realized, and the SS-OCT-based surgical navigation system is rapidly developed in the clinical field. However, in practical applications, the SS-OCT-based surgical navigation system still has a series of problems, wherein the most serious problem for doctors is the problem of image distortion caused by refraction effects and scattering effects of different tissue structures in the imaging process.
Biological tissue is not completely transparent to light, photons can interact with the biological tissue when the photons propagate in the tissue, so that absorption, scattering, refraction and reflection phenomena are generated, and the SS-OCT extracts the amplitude, phase and polarization characteristics of the light propagating in the biological tissue by using a coherence gate method so as to acquire a chromatographic image of the light. However, in the imaging process, the refraction effect and the scattering effect of different tissues and physiological structures have certain differences, so that the OCT image of the biological tissue sample can be deformed and distorted to a certain extent. For such OCT image distortion caused by refraction and scattering effects, many methods of image correction have been proposed. Chong et al (Ultrahigh resolution retinal imaging by visible light OCT with longitudinal imaging. Biomed Opt express.2018;9 (4): 1477-1491) uses a color difference compensation method to compensate for longitudinal color differences in OCT images of the retina, and the autocorrelation function of the speckle is axially contracted by twenty percent without transverse changes, so that layered structures such as choroid and retinal pigment epithelium are clearly displayed in the visual field during imaging, longitudinal distortion is eliminated, and image quality is improved. The model calculation is carried out on different surfaces of three-dimensional OCT volume data by utilizing ray tracing in papers (Optical distortion correction in Optical Coherence Tomography for quantitative ocular anterior segment by three-dimensional imaging. Opt. Express 18,2782-2796 (2010)), OCT image distortion caused by refraction and scattering effects is subjected to two-dimensional and three-dimensional optical correction after denoising, layering, delaunay sectioning and other steps, the estimation precision of the curvature radius of an eye surface is obviously improved, and the difference between the corrected estimation precision and a standard value is less than 1%, so that an intraocular image is more accurate and clear. However, in the clinical use process of SS-OCT, only the distortion correction of tissue imaging cannot meet the needs of a doctor, the doctor needs to continuously image the focus position in real time in the operation process, and the intervention of a surgical instrument brings more distortion and even shielding to the focus region image, which has serious influence on the positioning of the focus, the observation of adjacent tissues and the implementation of the operation.
Therefore, there is a need for a more reliable solution to correct OCT images of SS-OCT surgical navigation systems.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an OCT image correction method and system of an SS-OCT operation navigation system aiming at the defects in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme: an OCT image correction method for an SS-OCT surgical navigation system, comprising the steps of:
1) Dividing a target area in an OCT image into three parts according to the relative position of a scalpel and a tissue structure, namely an area I, an area II and an area III, on the distorted OCT image acquired in an SS-OCT operation navigation system;
the region I is vertically distorted, the region I, the region II and the region III are sequentially connected in the transverse direction, a surgical knife adopted in the SS-OCT surgical navigation system comprises a knife handle and a knife head connected to the knife handle, and the knife head is provided with a knife tip;
the region I is a tissue internal distortion region, and the knife tip is stopped at the junction of the scalpel and the tissue; the area II is a boundary distortion area and comprises an area within a certain range of the boundary between the scalpel and the tissue; the region III is a normal region outside the tissue, and the boundary of one end, far away from the region I, of the boundary distortion region is stopped at the tail end of the scalpel handle;
2) Correcting the vertical distortion of the area I: vertically translating the region I, and stopping when the continuity of the whole boundary of the scalpel in the translated image meets the preset requirement;
3) Correcting the distortion of the area II: selecting a region corresponding to a region II in the distorted OCT image processed in the step 2) from an original OCT image without a scalpel, marking the region as a background II, covering the region II in the distorted OCT image processed in the step 2) with the background II in the original OCT image, connecting the upper and lower boundaries of a scalpel part in the region I with the upper and lower boundaries of the scalpel part in the region II respectively by using a white solid line, and setting the internal region of the connected scalpel part in the region II as black;
4) Area iii is used as a reference for step 2) and step 3) and is not processed to obtain corrected OCT images.
Preferably, in the step 1), the target area is divided into an area i, an area ii and an area iii by 9 reference points, and the area i, the area ii and the area iii are sequentially connected from left to right, and the 9 reference points are sequentially marked as reference points 1 to 9;
wherein, datum point 1 is the knife tip, datum point 2 and datum point 3 are the upper end point and the lower end point of tool bit and handle of a knife junction respectively, datum points 4, 5, 6, 7 are the 4 endpoints of the boundary of the handle of a knife and the crossing region of region II, datum point 8 and datum point 9 are the upper boundary point and the lower boundary point of the extreme right of handle of a knife respectively.
Preferably, the method for extracting the reference points 1 to 9 in the distorted OCT image is as follows:
1-1) searching the center of gravity of an image, setting a region of interest (ROI) of pixels A by pixels B at the center of gravity of the obtained image, and detecting the position of a datum point 1 in the region of the ROI by utilizing angular points;
1-2) screening the connected domain of the image, and reserving the connected domain with the largest area, wherein the connected domain comprises the whole lower surface boundary of the scalpel, and the rightmost end point obtained through boundary traversal is a datum point 9; searching the first white pixel point vertically upwards by taking the datum point 9 as a starting point to serve as a datum point 8;
1-3) extracting the boundary of the lower surface of the scalpel from a connected domain with the largest area through a datum point 1 and a datum point 9, and then selecting a gradient change extreme point through gradient analysis of continuous pixel points and combining the gradient change extreme point with a Shi-Tomasi corner detection result to obtain the positions of the datum point 3, the datum point 5 and the datum point 7;
1-4) searching the first white pixel point vertically upwards by using the datum point 3 as a datum point 2, searching the first white pixel point vertically upwards by using the datum point 5 as a datum point 4, and searching the first white pixel point vertically upwards by using the datum point 7 as a datum point 6, so as to finish 9 datum point extraction.
Preferably, in the step 1), the method for dividing the region i includes:
making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 1, and marking the vertical line as a first vertical line; making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 4 and the datum point 5, and marking the vertical line as a second vertical line;
the line segment 124 obtained by connecting the reference point 1, the reference point 2, and the reference point 4 in this order by a straight line is defined as an upper boundary i, and a region surrounded by the first vertical line, the upper boundary i, the second vertical line, and the lower boundary of the distorted OCT image is divided as a region i.
The segmentation method of the region II comprises the following steps: making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 6 and the datum point 7, marking as a third vertical line, and connecting the datum point 4 and the datum point 6 through a straight line to obtain a line segment 46 serving as an upper boundary II; the region surrounded between the second vertical line, the upper boundary ii, the third vertical line, and the lower boundary of the distorted OCT image is divided as a region ii.
Preferably, the dividing method of the region III is as follows: making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 8 and the datum point 9, marking as a fourth vertical line, and connecting the datum point 6 and the datum point 8 through a straight line to obtain a line segment 68 serving as an upper boundary III; the region surrounded between the third vertical line, the upper boundary iii, the fourth vertical line, and the lower boundary of the distorted OCT image is divided as a region iii.
Preferably, the step 2) specifically includes: vertically translating the whole area I, correspondingly marking point distribution after the translation of the datum points 1 to 5 as a datum point 1 'to a datum point 5', connecting the datum point 2 'and the datum point 4' by a straight line as a line segment 2'4', connecting the datum point 4 'and the datum point 6 by a straight line as a line segment 4'6, and connecting the datum point 6 and the datum point 8 by a straight line as a line segment 68;
the judgment method for meeting the preset requirements on the continuity of the whole boundary of the scalpel in the translated image is that the translated region I meets the following conditions: the difference between the gradient values of line segment 4'6 and line segment 68 is less than the set threshold K, and the difference between the gradient values of line segment 2'4' and line segment 68 is also less than the set threshold K.
Preferably, after said step 2) of translating, the upper boundary ii becomes a line segment 4'6, the region ii being in particular the region enclosed between the second vertical line, the line segment 4'6, the third vertical line and the lower boundary of the OCT image;
the step 3) is specifically as follows: selecting an area corresponding to the area II in the distorted OCT image processed in the step 2) from the original OCT image without a scalpel, marking the area as a background II, covering the area II in the distorted OCT image processed in the step 2) with the background II in the original OCT image, connecting the datum point 4 'with the datum point 6 by using a white solid line, connecting the datum point 5' with the datum point 7, and embedding the area surrounded by the datum point 4', the datum point 6, the datum point 7 and the datum point 5' after being sequentially connected by straight lines into black, thereby finishing the correction of the distortion of the area II.
Preferably, in the step 1-1), a=b=100
The invention also provides an OCT image correction system for the SS-OCT operation navigation system, which corrects the distorted OCT image obtained by the SS-OCT operation navigation system by adopting the method.
The beneficial effects of the invention are as follows: according to the OCT image correction method for the SS-OCT operation navigation system, the reference points are arranged according to the position relation between the surgical knife and the tissue structure in the operation, the reference points are used for dividing the OCT image, and then the distortion correction is carried out pertinently according to the characteristics of each region, so that the image distortion caused by refraction and scattering effects in the operation process is effectively eliminated, the OCT image is more visual and vivid, and great convenience is brought to the positioning of focus, the observation of adjacent tissues and the operation implementation.
Drawings
FIG. 1 is a flow chart of an OCT image correction method for an SS-OCT surgical navigation system of the present invention;
FIG. 2 is an OCT image of distortion prior to correction in an embodiment of the present invention;
FIG. 3 is a schematic illustration of labeling of regions, fiducial points of a distorted OCT image in an embodiment of the present invention;
fig. 4 is an OCT image after correction in an embodiment of the present invention.
Detailed Description
The present invention is described in further detail below with reference to examples to enable those skilled in the art to practice the same by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
Example 1
Referring to fig. 1, an OCT image correction method for an SS-OCT surgical navigation system of the present embodiment includes the steps of:
s1, dividing a target area in an OCT image into three parts according to the relative position of a scalpel and a tissue structure, namely a region I, a region II and a region III, of the distorted OCT image acquired in an SS-OCT operation navigation system;
the region I is vertically distorted, the region I, the region II and the region III are sequentially connected in the transverse direction, a surgical knife adopted in the SS-OCT surgical navigation system comprises a knife handle and a knife head connected to the knife handle, and the knife head is provided with a knife tip; in this embodiment, an artificial precious stone scalpel is selected, the tissue structure below the scalpel is clearly visible, and the OCT image distortion caused by refraction and scattering effects is small. The distorted OCT image is corrected with the aid of the rigid characteristic of the scalpel in this embodiment.
The region I is a tissue internal distortion region, and the knife tip is stopped at the junction of the scalpel and the tissue; the area II is a boundary distortion area and comprises an area within a certain range of the boundary between the scalpel and the tissue; region III is the normal region outside the tissue, and the boundary of the end of the boundary distortion region away from region I ends at the end of the scalpel handle.
Referring to fig. 3, in the step S1, a target area is divided into an area i, an area ii and an area iii by selecting 9 reference points in an image, and the area i, the area ii and the area iii are sequentially connected from left to right, and the 9 reference points are sequentially marked as reference points 1 to 9;
wherein, datum point 1 is the knife tip, datum point 2 and datum point 3 are the upper end point and the lower end point of tool bit and handle of a knife junction respectively, datum points 4, 5, 6, 7 are the 4 endpoints of the boundary of the handle of a knife and the crossing region of region II, datum point 8 and datum point 9 are the upper boundary point and the lower boundary point of the extreme right of handle of a knife respectively.
Specifically, the method for extracting the reference points 1 to 9 from the distorted OCT image comprises the following steps:
1-1) searching the center of gravity of an image, setting a region of interest (ROI) of 100 pixels by 100 pixels at the center of gravity of the obtained image, and detecting the position of a datum point 1 in the region of the ROI by utilizing a corner point;
1-2) screening the connected domain of the image, and reserving the connected domain with the largest area, wherein the connected domain comprises the whole lower surface boundary of the scalpel, and the rightmost end point obtained through boundary traversal is a datum point 9; searching the first white pixel point vertically upwards by taking the datum point 9 as a starting point to serve as a datum point 8;
1-3) extracting the boundary of the lower surface of the scalpel from a connected domain with the largest area through a datum point 1 and a datum point 9, and then selecting a gradient change extreme point through gradient analysis of continuous pixel points and combining the gradient change extreme point with a Shi-Tomasi corner detection result to obtain the positions of the datum point 3, the datum point 5 and the datum point 7;
1-4) searching the first white pixel point vertically upwards by using the datum point 3 as a datum point 2, searching the first white pixel point vertically upwards by using the datum point 5 as a datum point 4, searching the first white pixel point vertically upwards by using the datum point 7 as a datum point 6, completing 9 datum point extraction, and then dividing three areas, wherein the specific steps are as follows.
The segmentation method of the region I comprises the following steps:
making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 1, and marking the vertical line as a first vertical line; making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 4 and the datum point 5, and marking the vertical line as a second vertical line;
the line segment 124 obtained by connecting the reference point 1, the reference point 2, and the reference point 4 in this order by a straight line is defined as an upper boundary i, and a region surrounded by the first vertical line, the upper boundary i, the second vertical line, and the lower boundary of the distorted OCT image is divided as a region i.
The segmentation method of the region II comprises the following steps: making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 6 and the datum point 7, marking as a third vertical line, and connecting the datum point 4 and the datum point 6 through a straight line to obtain a line segment 46 serving as an upper boundary II; the region surrounded between the second vertical line, the upper boundary ii, the third vertical line, and the lower boundary of the distorted OCT image is divided as a region ii.
The dividing method of the region III comprises the following steps: making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 8 and the datum point 9, marking as a fourth vertical line, and connecting the datum point 6 and the datum point 8 through a straight line to obtain a line segment 68 serving as an upper boundary III; the region surrounded between the third vertical line, the upper boundary iii, the fourth vertical line, and the lower boundary of the distorted OCT image is divided as a region iii.
S2, correcting vertical distortion of the area I
And vertically translating the region I, and stopping when the continuity of the whole boundary of the scalpel in the translated image meets the preset requirement. For the internal distortion region of the tissue, the distortion of the internal distortion region is influenced by the scalpel and only exists in the vertical direction, so that the correction meeting the requirement can be realized through vertical translation.
The specific method comprises the following steps: vertically translating the whole area I, correspondingly marking point distribution after the translation of the datum points 1 to 5 as a datum point 1 'to a datum point 5', connecting the datum point 2 'and the datum point 4' by a straight line as a line segment 2'4', connecting the datum point 4 'and the datum point 6 by a straight line as a line segment 4'6, and connecting the datum point 6 and the datum point 8 by a straight line as a line segment 68;
the judgment method for meeting the preset requirements on the continuity of the whole boundary of the scalpel in the translated image is that the translated region I meets the following conditions: when the difference between the gradient values of the line segment 4'6 and the line segment 68 is smaller than the set threshold K, and the difference between the gradient values of the line segment 2'4 'and the line segment 68 is also smaller than the set threshold K, that is, the gradient values of the line segment 2'4', the line segment 4'6 and the line segment 68 are similar, the continuity of the whole boundary of the scalpel is good. Of course, it can be determined by comparing the slopes of the three line segments, and it is preferable to indicate that the continuity is good when the slopes of the three line segments (line segments 2'4', 4'6, and 68) are similar.
S3, correcting the distortion of the area II
For the tissue boundary distortion image, the distortion is too complex and has little influence on the surgical navigation, so the requirement can be met by covering the image at the boundary in the original OCT image.
After the translation in the step S2, the upper boundary ii becomes a line segment 4'6, and the region ii is specifically a region surrounded by the second vertical line, the line segment 4'6, the third vertical line, and the lower boundary of the OCT image;
the specific method for correcting the distortion of the area II comprises the following steps: selecting an area corresponding to an area II in the distorted OCT image processed in the step S2 from the original OCT image without a scalpel, marking the area as a background II, covering the area II in the distorted OCT image processed in the step S2 with the background II in the original OCT image, connecting a datum point 4 'with a datum point 6 by using a white solid line, connecting a datum point 5' with a datum point 7, and embedding the areas surrounded by the datum point 4', the datum point 6, the datum point 7 and the datum point 5' after being sequentially connected in a straight line into black, so as to establish a continuous scalpel boundary, and correcting the distortion of the area II.
S4, taking the area III as a reference of the step S2 and the step S3, and obtaining corrected OCT images without processing. For the normal image outside the tissue, the partial image is used for reference when the internal distortion image and the tissue boundary distortion image are adjusted, distortion does not exist, and redundant processing is not carried out.
Referring to fig. 2, in order to facilitate understanding, each region, boundary, and reference point in the distorted OCT image are labeled in detail in fig. 3 for the distorted OCT image before correction in this embodiment. The image 4 is an OCT image corrected in this embodiment, and it can be seen that in the corrected OCT image, the image distortion caused by the refraction and scattering effects is substantially eliminated, so that the requirement of SS-OCT operation navigation can be primarily satisfied.
Example 2
The present embodiment provides an OCT image correction system for an SS-OCT surgical navigation system that corrects distorted OCT images obtained by the SS-OCT surgical navigation system using the method of embodiment 1.
Although embodiments of the present invention have been disclosed above, it is not limited to the use of the description and embodiments, it is well suited to various fields of use for the invention, and further modifications may be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the particular details without departing from the general concepts defined in the claims and the equivalents thereof.
Claims (9)
1. An OCT image correction method for an SS-OCT surgical navigation system, comprising the steps of:
1) Dividing a target area in an OCT image into three parts according to the relative position of a scalpel and a tissue structure, namely an area I, an area II and an area III, on the distorted OCT image acquired in an SS-OCT operation navigation system;
the region I is vertically distorted, the region I, the region II and the region III are sequentially connected in the transverse direction, a surgical knife adopted in the SS-OCT surgical navigation system comprises a knife handle and a knife head connected to the knife handle, and the knife head is provided with a knife tip;
the region I is a tissue internal distortion region, and the knife tip is stopped at the junction of the scalpel and the tissue; the area II is a boundary distortion area and comprises an area within a certain range of the boundary between the scalpel and the tissue; the region III is a normal region outside the tissue, and the boundary of one end, far away from the region I, of the boundary distortion region is stopped at the tail end of the scalpel handle;
2) Correcting the vertical distortion of the area I: vertically translating the region I, and stopping when the continuity of the whole boundary of the scalpel in the translated image meets the preset requirement;
3) Correcting the distortion of the area II: selecting a region corresponding to a region II in the distorted OCT image processed in the step 2) from an original OCT image without a scalpel, marking the region as a background II, covering the region II in the distorted OCT image processed in the step 2) with the background II in the original OCT image, connecting the upper and lower boundaries of a scalpel part in the region I with the upper and lower boundaries of the scalpel part in the region II respectively by using a white solid line, and setting the internal region of the connected scalpel part in the region II as black;
4) Area iii is used as a reference for step 2) and step 3) and is not processed to obtain corrected OCT images.
2. The OCT image correction method for an SS-OCT surgical navigation system according to claim 1, wherein in step 1), the target region is divided into a region i, a region ii, and a region iii by 9 reference points, and the region i, the region ii, and the region iii are sequentially connected from left to right, and the 9 reference points are sequentially designated as reference points 1 to 9;
wherein, datum point 1 is the knife tip, datum point 2 and datum point 3 are the upper end point and the lower end point of tool bit and handle of a knife junction respectively, datum points 4, 5, 6, 7 are the 4 endpoints of the boundary of the handle of a knife and the crossing region of region II, datum point 8 and datum point 9 are the upper boundary point and the lower boundary point of the extreme right of handle of a knife respectively.
3. The OCT image correction method for an SS-OCT surgical navigation system according to claim 2, wherein the method of extracting the reference points 1 to 9 in the distorted OCT image is:
1-1) searching the center of gravity of an image, setting a region of interest (ROI) of pixels A by pixels B at the center of gravity of the obtained image, and detecting the position of a datum point 1 in the region of the ROI by utilizing angular points;
1-2) screening the connected domain of the image, and reserving the connected domain with the largest area, wherein the connected domain comprises the whole lower surface boundary of the scalpel, and the rightmost end point obtained through boundary traversal is a datum point 9; searching the first white pixel point vertically upwards by taking the datum point 9 as a starting point to serve as a datum point 8;
1-3) extracting the boundary of the lower surface of the scalpel from a connected domain with the largest area through a datum point 1 and a datum point 9, and then selecting a gradient change extreme point through gradient analysis of continuous pixel points and combining the gradient change extreme point with a Shi-Tomasi corner detection result to obtain the positions of the datum point 3, the datum point 5 and the datum point 7;
1-4) searching the first white pixel point vertically upwards by using the datum point 3 as a datum point 2, searching the first white pixel point vertically upwards by using the datum point 5 as a datum point 4, and searching the first white pixel point vertically upwards by using the datum point 7 as a datum point 6, so as to finish 9 datum point extraction.
4. The method for correcting OCT images for an SS-OCT surgical navigation system according to claim 3, wherein in the step 1), the segmentation method of the region i is:
making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 1, and marking the vertical line as a first vertical line; making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 4 and the datum point 5, and marking the vertical line as a second vertical line;
sequentially connecting the datum point 1, the datum point 2 and the datum point 4 through straight lines, taking the obtained line segment 124 as an upper boundary I, and dividing a region surrounded by the first vertical line, the upper boundary I, the second vertical line and the lower boundary of the distorted OCT image into a region I;
the segmentation method of the region II comprises the following steps: making a vertical line along the vertical direction of the distorted OCT image by passing the datum point 6 and the datum point 7, marking as a third vertical line, and connecting the datum point 4 and the datum point 6 through a straight line to obtain a line segment 46 serving as an upper boundary II; the region surrounded between the second vertical line, the upper boundary ii, the third vertical line, and the lower boundary of the distorted OCT image is divided as a region ii.
5. The OCT image correction method for an SS-OCT surgical navigation system according to claim 4, wherein the segmentation method of the region iii is: making a vertical line along the vertical direction of the distorted OCT image by passing through the datum point 8 and the datum point 9, marking as a fourth vertical line, and connecting the datum point 6 and the datum point 8 through a straight line to obtain a line segment 68 serving as an upper boundary III; the region surrounded between the third vertical line, the upper boundary iii, the fourth vertical line, and the lower boundary of the distorted OCT image is divided as a region iii.
6. The OCT image correction method for an SS-OCT surgical navigation system according to claim 5, wherein step 2) specifically comprises: vertically translating the whole area I, correspondingly marking point distribution after the translation of the datum points 1 to 5 as a datum point 1 'to a datum point 5', connecting the datum point 2 'and the datum point 4' by a straight line as a line segment 2'4', connecting the datum point 4 'and the datum point 6 by a straight line as a line segment 4'6, and connecting the datum point 6 and the datum point 8 by a straight line as a line segment 68;
the judgment method for meeting the preset requirements on the continuity of the whole boundary of the scalpel in the translated image is that the translated region I meets the following conditions: the difference between the gradient values of line segment 4'6 and line segment 68 is less than the set threshold K, and the difference between the gradient values of line segment 2'4' and line segment 68 is also less than the set threshold K.
7. The method for correcting OCT images for an SS-OCT surgical navigation system according to claim 6, wherein after the step 2) of translation, the upper boundary ii becomes a line segment 4'6, and the region ii is specifically a region surrounded between the second vertical line, the line segment 4'6, the third vertical line, and the lower boundary of the OCT image;
the step 3) is specifically as follows: selecting an area corresponding to the area II in the distorted OCT image processed in the step 2) from the original OCT image without a scalpel, marking the area as a background II, covering the area II in the distorted OCT image processed in the step 2) with the background II in the original OCT image, connecting the datum point 4 'with the datum point 6 by using a white solid line, connecting the datum point 5' with the datum point 7, and embedding the area surrounded by the datum point 4', the datum point 6, the datum point 7 and the datum point 5' after being sequentially connected by straight lines into black, thereby finishing the correction of the distortion of the area II.
8. The OCT image correction method for SS-OCT surgical navigation system according to claim 3, wherein in step 1-1), a=b=100.
9. OCT image correction system for an SS-OCT surgical navigation system, characterized in that it corrects distorted OCT images obtained by the SS-OCT surgical navigation system using the method according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110454010.2A CN113012151B (en) | 2021-04-26 | 2021-04-26 | OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110454010.2A CN113012151B (en) | 2021-04-26 | 2021-04-26 | OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113012151A CN113012151A (en) | 2021-06-22 |
| CN113012151B true CN113012151B (en) | 2024-02-13 |
Family
ID=76380364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110454010.2A Active CN113012151B (en) | 2021-04-26 | 2021-04-26 | OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113012151B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114445353B (en) * | 2022-01-12 | 2023-03-24 | 广州永士达医疗科技有限责任公司 | OCT image deformation detection method and device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1719477A (en) * | 2005-05-19 | 2006-01-11 | 上海交通大学 | Calibration method of pick up camera or photographic camera geographic distortion |
| CN103698301A (en) * | 2014-01-03 | 2014-04-02 | 北京航空航天大学 | Improved SD-OCT (spectral domain-optical coherence tomography) system |
| CN110996836A (en) * | 2017-07-27 | 2020-04-10 | 阿莱恩技术有限公司 | System and method for processing orthodontic appliances by optical coherence tomography |
| JP2020137672A (en) * | 2019-02-27 | 2020-09-03 | 株式会社トプコン | Ophthalmologic information processing apparatus, ophthalmologic apparatus, ophthalmologic information processing method, and program |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090003666A1 (en) * | 2007-06-27 | 2009-01-01 | Wu Dee H | System and methods for image analysis and treatment |
-
2021
- 2021-04-26 CN CN202110454010.2A patent/CN113012151B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1719477A (en) * | 2005-05-19 | 2006-01-11 | 上海交通大学 | Calibration method of pick up camera or photographic camera geographic distortion |
| CN103698301A (en) * | 2014-01-03 | 2014-04-02 | 北京航空航天大学 | Improved SD-OCT (spectral domain-optical coherence tomography) system |
| CN110996836A (en) * | 2017-07-27 | 2020-04-10 | 阿莱恩技术有限公司 | System and method for processing orthodontic appliances by optical coherence tomography |
| JP2020137672A (en) * | 2019-02-27 | 2020-09-03 | 株式会社トプコン | Ophthalmologic information processing apparatus, ophthalmologic apparatus, ophthalmologic information processing method, and program |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113012151A (en) | 2021-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1976424B1 (en) | A method of eye examination by optical coherence tomography | |
| CN111616800B (en) | Ophthalmic surgery navigation system | |
| Patel et al. | Quantitative analysis of in vivo confocal microscopy images: a review | |
| US9833136B2 (en) | Systems and methods for ocular anterior segment tracking, alignment, and dewarping using optical coherence tomography | |
| CN102136135B (en) | Method for extracting inner outline of cornea from optical coherence tomography image of anterior segment of eye and method for extracting inner outline of anterior chamber from optical coherence tomography image of anterior segment of eye | |
| US20070103693A1 (en) | Method of bioimage data processing for revealing more meaningful anatomic features of diseased tissues | |
| WO2013188885A1 (en) | Non-invasive 3d imaging and measuring of anterior chamber angle of the eye | |
| JP2014500096A (en) | Scanning and processing using optical coherence tomography | |
| JP6758826B2 (en) | Image processing device and image processing method | |
| CN108765388B (en) | Automatic segmentation method and system for esophageal endoscopic OCT (optical coherence tomography) image hierarchical structure | |
| JP7368568B2 (en) | ophthalmology equipment | |
| CN113012151B (en) | OCT (optical coherence tomography) image correction method and system for SS-OCT operation navigation system | |
| Xin et al. | Optical coherence tomography-based deep learning algorithm for quantification of the location of the intraocular lens | |
| US10733735B2 (en) | Ophthalmic apparatus | |
| CN105411523A (en) | Cornea image processing method | |
| JP6882242B2 (en) | Ophthalmic equipment and its control method | |
| Wang et al. | Primary acute angle-closure glaucoma: three-dimensional reconstruction imaging of optic nerve heard structure in based on optical coherence tomography (OCT) | |
| Tang et al. | Correction of refractive and scattered image distortions in optical coherence tomography based on scalpel | |
| JP7201852B2 (en) | Ophthalmic device, its control method, program, and recording medium | |
| US20230115056A1 (en) | Ophthalmic apparatus, method of controlling the same, and recording medium | |
| Pchelkina et al. | An Algorithm for Automatic Image Segmentation Using the Sobel Method for an Optical Coherence Tomography | |
| JP2023066499A (en) | Ophthalmologic information processing device, ophthalmologic device, ophthalmologic information processing method, and program | |
| Kim | Dynamic Biomechanical Characteristics of the Optic Nerve Head by OCT Imaging | |
| Williams et al. | A 3D segmentation framework for cornea segmentation in anterior segment OCT images using level set technique with shape prior | |
| Akhlaghi et al. | Mansooreh Montazerin1, Zahra Sajjadifar1, Elias Khalili Pour2, Hamid Riazi‑Esfahani2, Tahereh Mahmoudi3, Hossein Rabbani4, Hossein Movahedian5, Alireza Dehghani5 |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |