KR101355174B1 - Calibrating system of OCT probe optical traictory and the method - Google Patents

Abstract

In accordance with another aspect of the present invention, there is provided an OCT probe optical trajectory correcting apparatus comprising: a driving signal generation unit configured to output a signal for a frequency, a voltage, and a phase with respect to a first axis and a second axis; An amplifier for amplifying and outputting frequency, voltage, and phase signals of the first and second axes output from the driving signal generator; A probe for projecting an optical trace signal onto a screen in response to the frequency, voltage, and phase control signals of the first and second axes amplified by the amplifier; A camera for photographing the light trajectory image projected on the screen; A correction controller configured to compare the optical trajectory image photographed by the camera with a preset optical trajectory image to generate correction values for controlling the frequency, voltage, and phase of the first and second axes to be identical to the preset optical trajectory image Its features are to include.
According to the present invention, the OCT probe optical trajectory correction device and its correction method compares the optical trajectory image photographed on the opposite side of the probe with a preset circular trajectory so that the trajectory of the light irradiated through the OCT probe can form a circular trajectory. The driving conditions of the probe according to the compensation value can be adjusted.

Description

OCT probe optical trajectory correction device and its correction method {Calibrating system of OCT probe optical traictory and the method}

The present invention relates to an OCT probe optical trajectory correcting apparatus and a method of correcting the same, and in particular, a light trajectory image photographed on the opposite side of a probe so that the trajectory of light irradiated through the OCT probe can form a circular trajectory. The present invention relates to an OCT probe optical trajectory correcting apparatus capable of adjusting a driving condition of a probe according to a correction value, and a correction method thereof.

Recently, optical coherence tomography (OCT), which is simpler in structure than a computed tomography or magnetic resonance imaging (OCT) and can provide a higher resolution than an ultrasound imaging apparatus, is under development.

The optical coherence detection apparatus is a device for irradiating low coherence light close to natural light to multiple scattering materials such as a living body and detecting light reflected from the material to obtain a tomographic image for a living body.

These conventional optical tomography apparatuses are characterized and manufactured according to the samples corresponding to the respective wavelength characteristics, and tomographic images of the same samples are obtained using different systems.

In other words, SD-OCT with a center wavelength of 840 nm is well absorbed by substances such as water, and is widely used for diagnosis of diseases in the central vein of the ophthalmic retina. SS-OCT having a central wavelength of 1050 nm is compared with 840 nm It is widely applied to diagnosis of diseases of vascular tissues because of its long wavelength.

In order to accurately obtain the final tomographic image, the optical tomography apparatus inserts a spectroscope into the system or adds the spectroscope separately to obtain information on the pixel-to-wavelength region to analyze the performance of the optical system.

OCT Probe Scanners are structurally diverse methods such as polygon mirrors, galvanometer mirrors, and MEMS mirrors, and OCT is used in ophthalmology and dermatology.

Meanwhile, a probe structure using a PZT (piezoelectric element) is currently being developed as an OCT probe structure, which is composed of a base, a PZT, a ferrule, an optical fiber, an FC connector, and a probe case. This is structurally simple and can be applied to a small size, and it is advantageous that three-dimensional images can be obtained by only driving the horizontal axis and the vertical axis of PZT.

Such an OCT probe has a problem that the scan area can not be secured because the optical path does not form an accurate circle during the initial operation.

The technical problem to be solved by the present invention is to drive the probe according to the correction value by comparing the optical trajectory image photographed on the opposite side of the probe with the preset circular trajectory so that the trajectory of the light irradiated through the probe of the OCT to form a circular trajectory It is to provide an OCT probe optical trajectory correction device that can adjust the conditions, and a correction method thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an aspect of the present invention, there is provided an OCT probe optical trajectory correcting apparatus comprising: a driving signal generation unit configured to output signals for frequency, voltage, and phase with respect to a first axis and a second axis; An amplifier for amplifying and outputting frequency, voltage, and phase signals of the first and second axes output from the driving signal generator; A probe for projecting an optical trace signal onto a screen in response to the frequency, voltage, and phase control signals of the first and second axes amplified by the amplifier; A camera for photographing the light trajectory image projected on the screen; A correction controller configured to compare the optical trajectory image photographed by the camera with a preset optical trajectory image to generate correction values for controlling the frequency, voltage, and phase of the first and second axes to be identical to the preset optical trajectory image Its features are to include.

The correction controller may include: a voltage sensor configured to sense voltages of the first and second axes output from the amplifier; A current sensor for sensing currents of the first and second axes output from the amplifier; A phase detector for detecting a phase of a resonant frequency corresponding to voltages and currents of the first and second axes sensed by the voltage sensor and the current sensor; An image comparing unit comparing the light trajectory image value photographed by the camera with a preset light trajectory image value and calculating a correction value for the difference; It is characterized in that it comprises a correction unit for outputting control values for the frequency, voltage and phase for the first axis and the second axis corresponding to the correction value calculated by the image comparison unit.

Here, the correction unit is characterized in that it outputs a correction value according to the change in the phase of the resonant frequency of the first axis and the second axis detected by the phase detection unit.

Here, the correction unit is characterized in that the phase of the resonance frequency of the first axis and the second axis is controlled to be a difference of 90 °.

Here, the correction unit corrects each resonance frequency such that the current phase and the voltage phase of the resonance frequency of the first axis and the current phase and the voltage phase of the resonance frequency of the second axis detected by the phase detector are in phase. There is this.

Here, the predetermined light trajectory image of the image comparison unit is characterized in that the shape of the garden.

The first and second axes of the driving signal generator are characterized in that they are output as signals for frequency, voltage, and phase for the X and Y axes.

Here, the probe is characterized in that it uses a piezoelectric element (PZT) having an electrode separated for each axis.

In addition, the OCT probe optical trajectory correction method according to the present invention includes the steps of photographing the optical trajectory output from the probe and projected on the screen; Comparing image data of the photographed light trajectory with image data of a predetermined light trajectory; Calculating a correction value from the compared value to generate frequency, voltage, and phase control values of the first and second axes; And controlling the frequency, voltage, and phase of the generated first and second axes to be equal to the preset optical trajectory image data.

Wherein before the photographing of the optical trajectory with a camera, outputting a signal for frequency, voltage, and phase for a first axis and a second axis in the probe; And amplifying and outputting frequency, voltage, and phase signals of the outputted first and second axes.

Here, in the step of generating the control value, it is characterized in that the phase of the resonant frequency of the first axis and the second axis corresponding to the voltage and current detected by the voltage sensor and the current sensor.

Here, in the step of generating the control value is characterized in that the control so that the phase of the resonant frequency of the first axis and the second axis is 90 ° difference.

Here, the first axis and the second axis is characterized in that the X axis and Y axis.

According to the present invention, the OCT probe optical trajectory correction device and its correction method compares the optical trajectory image photographed on the opposite side of the probe with the preset circular trajectory so that the trajectory of light irradiated through the OCT probe can form a circular trajectory. The driving conditions of the probe according to the compensation value can be adjusted.

1 is a view schematically showing the configuration of an OCT optical trajectory correction device according to the present invention.
2 is a view schematically showing the configuration of the probe of FIG.
3 is a diagram schematically illustrating a configuration of the correction controller of FIG. 1.
Figure 4 shows that the phase of the voltage-current according to the present invention is in phase.
5 is a diagram illustrating an example of detecting a resonant frequency according to the present invention.
6 illustrates an example of detecting a voltage and a phase according to the present invention.
7 is a flowchart illustrating an OCT optical trajectory correction method according to the present invention.
8 is a view showing a light trajectory image output from the probe according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to include an element does not exclude other elements unless specifically stated otherwise, but may also include other elements.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing a configuration of an OCT optical trajectory correcting apparatus according to the present invention, FIG. 2 is a view schematically showing a configuration of the probe of FIG. 1, and FIG. 3 is a view of the correction controller of FIG. 1. It is a figure which shows schematically a structure. As shown in FIG. 1, the OCT optical trajectory correcting apparatus includes a driving signal generator 110, an amplifier 120, 130, a probe 140, a camera 150, and a correction controller 160. do.

The driving signal generator 110 outputs a signal corresponding to the frequency, the voltage and the phase of the first axis and a signal corresponding to the frequency, the voltage and the phase of the second axis. At this time, the first axis and the second axis is preferably the frequency, voltage and phase for the two channels of the X-axis and the Y-axis.

The amplifiers 120 and 130 may include a first amplifier 120 for amplifying the signal of the first axis output from the driving signal generator 110 and a second amplifier 130 for amplifying the signal of the second axis. desirable.

As shown in FIG. 2, the probe 140 is configured in a manner using a PZT (piezoelectric element) and includes a base 101, an electrode 102, a PZT 103, a ferrule 104, and an optical fiber. (Optical Fiber) 105, consisting of an FC connector and a probe case covering the whole. Probes using PZT are structurally simple, and three-dimensional images can be obtained simply by driving the horizontal and vertical axes of the PZT.

The PZT 103 is a vibrating body which is coupled with a ferrule 104 of an OCT probe to vibrate the optical fiber 105 vertically or horizontally and has an electrode separated for each axis. PZT of two poles may be applied. The PZT 103 is a circular type and is composed of four electrodes 102 for supplying a sine wave of DC voltage.

The base 101 serves to fix the PZT 103 and is uniquely attached to an outer case so that the PZT can vibrate freely. At this time, about 3mm of PZT is inserted into the base and fixed with adhesive.

The ferrule 104 is a part through which the cladding of the optical fiber is stripped and serves to hold the optical fiber 105. At this time, if only 0.15 mm of the core stripped to 27 mm in length by the optical fiber 105 is passed through the ferrule, only the remaining 17 mm core portion remains except for the 10 mm ferrule length. In addition, when the PZT 103 is driven while the PZT 103, the base 101, the ferrule 104, and the optical fiber 105 are assembled, the core is driven at a natural vibration frequency of 17 mm. Vibrates.

The optical fiber 105 has one end of the FC type connection structure, and the other end of the SC type connection structure, one end is connected to the light source and the other is the outer coating, inner coating and cladding (Cladding) ) Only the core is stripped. The core is passed through the ferrol and fixed with an adhesive. In general, a light source having a wavelength of 1315 nm is used as the light source for the OCT probe.

The probe case (not shown) is fixed while protecting the assembled state of the optical fiber 105 and the ferrule 104, PZT 103 and the base 101 processed for the OCT probe therein, in particular the coating Since the core part of the peeled optical fiber is fragile, the core part is protected, and the probe 140 is easily formed by hand.

The probe 140 projects an optical locus signal on a screen corresponding to the frequency, voltage, and phase of the first axis and the frequency, voltage, and phase of the second axis amplified by the amplifiers 120 and 130.

More specifically, the PZT 103 operates by dividing the electrode of the PZT 103 into an X-axis and a Y-axis and supplying a sine wave DC power to each axis. In PZT operation, the amplitude of the PZT starts, and the optical fiber 105 configured with the PZT operates in a circular shape by the amplitude and draws a red circle. At this time, the most important is that the light source output from the optical fiber to create the correct garden, the frequency of the voltage and current for each axis supplied to the PZT (103) to make such a garden.

The camera 150 photographs a light trajectory image projected from the probe 140 onto the screen 107.

As shown in FIG. 3, the correction controller 160 includes a voltage sensor 301, a current sensor 302, a phase detector 303, an image comparator 305, and a correction unit 304. And a correction value for controlling the frequency, voltage, and phase of the first and second axes so as to be identical to the preset light trajectory image by comparing the light trajectory image photographed by the camera 150 with the preset light trajectory image. Create

The voltage sensor 301 senses the voltage of the first axis output from the first amplifier 120 and the voltage of the second axis output from the second amplifier 130.

The current sensor 302 senses the current of the first axis output from the first amplifier 120 and the current of the second axis output from the second amplifier 130.

The resonance frequency for each axis may be detected by the voltage and current sensed by the voltage sensor 301 and the current sensor 302.

The phase detector 303 detects a phase of a resonance frequency corresponding to the voltage and current of the first and second axes sensed by the voltage sensor 301 and the current sensor 302.

More specifically, when the initial frequency value (Reference) is input to drive the PZT 103, the input frequency is input to an amplifier of the X axis and the Y axis through a frequency generator, and the input is performed. The voltage is output as the maximum value for driving PZT. At this time, an external variable acts on the PZT 103 so that the resonance frequency is changed. Therefore, the voltage sensor (301) and the current sensor (302) are used to monitor the characteristic of the voltage supplied to the PZT (103) in order to track the resonant frequency that is out of range. Phase detector (Phase Detector) to detect the frequency of the detected phase, voltage, current and feedback the results for the resonant frequency tracking to input the control value.

4 is a diagram showing that the phase of the voltage-current according to the present invention is in phase. As shown in FIG. 4, when the frequency of the supplied voltage and current is the same and the phases are in phase, this becomes the resonance frequency, and when the resonance occurs, it can be said that the amplitude generally occurs at the greatest amplitude. In order to create a circle by the resonance frequency, the resonance phase of the X axis and the Y axis should have a difference of 90 °.

The image comparison unit 305 compares the light trajectory image data value photographed by the camera 150 with a preset light trajectory image data value and calculates a correction value for the difference.

More specifically, the predetermined light trajectory image of the image comparator 305 has a shape of a garden, and is a value of a resonant frequency in which the frequency of the supplied voltage and current is the same and the phases are in phase. This requires that the resonant phases of the X and Y axes have a 90 ° difference. At this time, the resonant frequency stored in the image comparator 305 and the resonant phase of the X-axis and the Y-axis are compared with the difference of 90 ° and the frequency, voltage, and phase values of the photographed optical trajectory image data values.

The correction unit 304 outputs control values for the frequency, voltage, and phase of the first and second axes corresponding to the correction values calculated by the image comparator 305. That is, a correction value corresponding to a change in the phase of the resonant frequencies of the first and second axes detected by the phase detector 303 is output, and the phase of the resonant frequencies of the first and second axes is 90 °. To control the difference.

In addition, the correction unit 304 is a resonant frequency such that the current phase and the voltage phase of the resonant frequency of the first axis detected by the phase detector 303 and the current phase and the voltage phase of the resonant frequency of the second axis are in phase. Will be corrected.

5 is a diagram illustrating an example of detecting a resonance frequency according to the present invention, and FIG. 6 is a diagram illustrating an example of detecting a voltage and a phase according to the present invention. As shown in FIG. 5, first, an optimum frequency must be found for the correct operation of the probe 140. To find the optimum frequency, a voltage of 5 [V] is applied to both axes and the frequency is controlled to obtain a frequency closest to the circle. Detect. At this time, when the frequency is 0 Hz, the light source does not operate in a circle, and when the frequency is applied to 363.5 Hz, the light source appears only on the X axis, and the frequency of 379.5 Hz shows that the light source is drawn and is about 0.5 mm larger. . In the case of 387.5Hz, it can be seen that the light source forms the origin at the center while the two axes operate. It can be seen that the optimum frequency. Thus, the optimum frequency of the ongoing probe can be 387.5 Hz.

As shown in FIG. 6, input to all channels was measured and changed. In (a), the frequency and voltage are the same, and the phase is set so that channel 1 is 90 ° ahead. And as a result of measuring the phase, it was confirmed that a circle was formed.

(b) shows the same frequency, voltage is 2.5 [V] at channel 1, voltage at channel 2

5 [V], the phase has channel 1 ahead 90 °. The measurement shows that the oval is drawn

Can be confirmed. Therefore, it can be seen that the output is accurate according to the control value of the frequency, voltage and phase.

7 is a flowchart illustrating an OCT optical trajectory correction method according to the present invention, and FIG. 8 is a view illustrating an optical trajectory image output from a probe according to the present invention. As shown in FIG. 7, in the OCT optical trajectory correcting method, first, the probe 140 outputs signals for frequency, voltage, and phase with respect to a first axis and a second axis, and then outputs the first axis and The frequency, voltage, and phase signals of the second axis are amplified and output. In operation S701, the optical trajectory output from the probe 140 is projected onto the screen by a camera.

Subsequently, the image data of the photographed light trajectory and the image data of the predetermined light trajectory are compared (S702). More specifically, the predetermined light trajectory image of the image comparator 305 has a shape of a garden, and is a value of a resonant frequency in which the frequency of the supplied voltage and current is the same and the phase is in phase. The resonant phases of the X and Y axes must have a difference of 90 °. At this time, the resonant frequency stored in the image comparator 305 and the resonant phase of the X-axis and the Y-axis are compared with the difference of 90 ° and the frequency, voltage, and phase values of the photographed optical trajectory image data values.

Next, a step of generating the frequency, voltage, and phase control values of the first and second axes by calculating a correction value from the compared values is performed (S703).

More specifically, the correction value for the frequency, voltage and phase for the first axis and the frequency, voltage and phase for the second axis at the frequency, voltage and phase for the garden of the preset optical trajectory. The difference is calculated to produce a control value.

Then, the step of controlling the frequency, voltage and phase of the generated first axis and the second axis to be the same as the predetermined optical trajectory image data (S704). That is, while controlling the frequency, voltage and phase for the first axis and the frequency, voltage and phase for the second axis with the generated control value, the control is equally performed in the shape of the garden of the light trajectory. At this time, the phase of the resonant frequency of the first axis and the second axis is controlled to be a difference of 90 °.

That is, as shown in FIG. 8, the driving signal generator 110 applies the frequency, voltage, and phase control values for the first and second axes to the probe 140 to the electrodes of the PZT. And make corrections.

While the present invention has been particularly shown and described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of course, this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents as well as the claims that follow.

110 --- Drive signal generator 140 --- Probe
150 --- Camera 160 --- Calibration Controls
301 --- voltage sensor 302 --- current sensor
303 --- Phase detector 304 --- Compensator
305 --- image comparison

Claims (13)

A driving signal generator for outputting signals corresponding to frequencies, voltages, and phases of the first and second axes;
An amplifier for amplifying and outputting signals of the first and second axes output from the driving signal generator;
A probe for projecting an optical trajectory signal for signals of the first and second axes amplified by the amplifying unit to a screen;
A camera for photographing the light trajectory image projected on the screen;
A correction controller configured to compare the optical trajectory image photographed by the camera with a preset optical trajectory image and generate correction values for controlling the frequency, voltage, and phase of the first and second axes to be identical to the preset optical trajectory image OCT probe optical trajectory correction apparatus comprising a.
The method of claim 1,
The correction control unit
A voltage sensor configured to sense voltages of the first and second axes output from the amplifier;
A current sensor for sensing currents of the first and second axes output from the amplifier;
A phase detector for detecting a phase of a resonant frequency corresponding to voltages and currents of the first and second axes sensed by the voltage sensor and the current sensor;
An image comparison unit comparing a light trajectory image value photographed by the camera with a preset light trajectory image value and calculating a correction value for the difference;
And a compensator for outputting control values for frequencies, voltages, and phases for the first and second axes corresponding to the compensation values calculated by the image comparator.
3. The method of claim 2,
And the corrector outputs a correction value according to a change in phase of each resonant frequency of the first axis and the second axis detected by the phase detector.
The method of claim 3, wherein
And the compensator controls the phase of the resonant frequency of the first axis and the second axis to be a difference of 90 °.
The method of claim 3, wherein
The correction unit corrects each resonant frequency such that the current phase and the voltage phase of the resonant frequency of the first axis and the current phase and the voltage phase of the resonant frequency of the second axis detected by the phase detector are in phase. Optical trajectory correction device.
3. The method of claim 2,
And a predetermined light trajectory image of the image comparing unit is a shape of a garden.
The method of claim 1,
And the first axis and the second axis of the driving signal generator output signals for frequencies, voltages, and phases of the X and Y axes.
The method of claim 1,
The probe is OCT probe optical trajectory correction device, characterized in that using a piezoelectric element (PZT) having an electrode separated for each axis.
Photographing the optical trajectory output from the probe and projected onto the screen with a camera;
Comparing image data of the photographed light trajectory with image data of a predetermined light trajectory;
Calculating a correction value from the compared value to generate frequency, voltage, and phase control values of the first and second axes;
And controlling a frequency, a voltage, and a phase of the generated first and second axes to be identical to the preset optical trajectory image data.
The method of claim 9,
Before the step of photographing the optical trajectory with a camera,
Outputting a signal for frequency, voltage and phase for a first axis and a second axis at the probe;
And amplifying and outputting the frequency, voltage, and phase signals of the outputted first and second axes.
The method of claim 9,
And generating a control value to detect phases of resonant frequencies of the first and second axes corresponding to voltages and currents sensed by voltage and current sensors.
The method of claim 9,
And generating a control value such that the phase of the resonant frequency of the first axis and the second axis is a difference of 90 °.
The method of claim 9,
And the first and second axes are X and Y axes.

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