CN102608208A - Dual-axis linkage based rapid scanning method of scanning acoustic microscope - Google Patents

Abstract

The invention discloses a dual-axis linkage based rapid scanning method of a scanning acoustic microscope. The method comprises the steps of: (1) setting a scanning area S=(N.a)*(N.a), and starting moving while taking Lscan=(N-1)a/ as the magnitude of motion displacements of motors at axes X and Y, wherein the motion directions of the axes X and Y are all positive directions; (2) when the two motors are stopped, changing the direction of the axis Y, maintaining the axis X unchanged, and moving while taking Lstep=a/ as the magnitudes of the motion displacements of the motors at the axes X and Y; (3) after the two motors are stopped, changing the motion direction of the axis X, maintaining the axis Y unchanged, and continuously starting the motion of the motors at the axes X and Y, wherein the magnitudes of displacements are both Lscan; (4) after the two motors are stopped, changing the motion direction of the axis X, maintaining the axis Y unchanged, and continuously starting the motion of the motors at the axes X and Y, wherein the magnitudes of the displacements are both Lstep; and (5) after the motors are stopped, repeating the steps from (1) to (4) until an entire image is scanned completely. According to the invention, on the premise of not changing motion system hardware conditions and not decreasing imaging resolution, the scanning efficiency can be increased by more than 20%.

Description

A kind of scanning ultrasonic microscope fast scanning method based on the twin shaft interlock

Technical field

The present invention relates to the quick method for scanning of micro-imaging, particularly a kind of scanning ultrasonic microscope fast scanning method based on the twin shaft interlock.

Background technology

Scanning ultrasonic microscope (SAM:Scanning Acoustic Microscope) is widely used in the Non-Destructive Testing and the assessment of The Key Electron Device and precision optical machinery parts, also is widely used in the microscopic observation of biological tissue simultaneously.

In the scanning ultrasonic microscope, often adopt the two-dimentional machinery scanning mechanism to carry probe and accomplish detection whole sample.The actuator of scanning mechanism generally all adopts linear electric motors or electric rotating machine to add precision ball screw.The traditional two-dimensional mechanic scanning mode is the grid scan pattern, makes the X spindle motor be responsible for line scanning, and every scanning finishes delegation, the y-axis motor stepping once, step size is a pairing size of pixel.When the X spindle motor carries out line scanning, gather echoed signal by the grating signal triggering high-speed AD card of X spindle motor, and be treated to the gray-scale value at this some place in the two dimensional image in real time.What the X spindle motor was reciprocal scans sample, until been scanned.

In order to improve the speed of scanning ultrasound wave micro-imaging, German KSI Inc. has adopted many probes sweeping scheme simultaneously, and promptly each scanning probe one sub regions is stitched together each sub regions then, forms final scanning result.Adopt N probe, just can practice thrift N so sweep time doubly.But this method has obviously increased cost.At present, the mode that external major company raises the efficiency all is that the hardware configuration to each motor proposes to optimize under existing grid scan pattern, satisfying under the prerequisite of kinematic accuracy, improves the speed of X or Y motor as much as possible.But this mode can not essence must significantly improve motor speed, and the maximal value of motor speed is subject to grating frequency and resolution.

Proposed the spiral scan pattern in the external research to AFM, but this scan pattern has not only increased the controller burden, and the picture point under the polar coordinates is transformed under the cartesian coordinate system can have brought corresponding site error again, Flame Image Process is comparatively loaded down with trivial details.In spiral scan, scan efficiency must be sacrificed to some extent could guarantee good stable property, and compares its sweep time not advantage in essence with traditional raster mode.Tradition grid scan pattern remains the microscopical scan pattern commonly used of sonde-type of industry member mechanical scanning class at present.

But the scan pattern of traditional grid fails to make full use of the collaborative work of X axle and y-axis motor, in scanning process, is that a driven by motor ultrasonic probe scans inefficiency all the time.Based on this; A kind of quick grid scan pattern based on the twin shaft coordinated type is proposed; Calculate and the experiment proof through theoretical; Under the situation that does not change any system hardware condition (like controller, driver etc.), can improve sweep speed more than 20%, and can not reduce the resolution that is formed images in the scanning back.

Summary of the invention

The objective of the invention is efficient, propose a kind of scanning ultrasonic microscope fast scanning method based on the twin shaft interlock for the scanning imagery that improves the scanning ultrasonic microscope.

Scanning ultrasonic microscope fast scanning method based on the twin shaft interlock; Adopt the scanning ultrasonic microscope, the scanning ultrasonic microscope comprises ultrasonic probe, X spindle motor, y-axis motor, Z spindle motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, sample to be detected; Sample to be detected is placed in the tank, ultrasonic probe be located at sample to be detected directly over, the top of ultrasonic probe is connected in the Z spindle motor; The Z spindle motor links to each other with y-axis motor; Y-axis motor links to each other with the X spindle motor, and X spindle motor, y-axis motor, Z spindle motor link to each other with electric machine controller, and ultrasonic probe links to each other with ultrasonic transmitter-receiver; Computing machine links to each other with ultrasonic transmitter-receiver, electric machine controller, display respectively, and the step of method is following:

1) after the start of scanning ultrasonic microscope, places sample to be detected, ultrasonic probe emission ultrasound wave;

2) size of scan area S=(Na) * (Na) is set in the computing machine of scanning ultrasonic microscope, wherein N by the resolution of one-tenth image, a is the size of single pixel;

3) y-axis motor is moved along positive dirction; The X spindle motor moves along negative direction; Making

is the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish a line scanning to sample to be detected;

4) after line scanning finishes; Changing y-axis motor direction of motion then is negative direction; X spindle motor direction of motion is constant; And make

and be the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finishes; Changing X spindle motor direction of motion again is positive dirction; Y-axis motor direction of motion is negative direction not yet; Making

is the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish the line scanning again to sample to be detected;

6) after line scanning finishes again; And then change X spindle motor direction of motion is negative direction; Y-axis motor direction of motion is constant; And make

and be the size of X sample to be detected and y-axis motor moving displacement; X sample to be detected and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), sample to be detected is come flyback retrace, until the entire image been scanned.

The beneficial effect that the present invention compared with prior art has is:

1) the present invention can improve scanning ultrasonic microscope scanning imagery efficient more than 20%;

2) the invention belongs to change, can not bring change, produce site error in the time of also can not causing image mapped, can not reduce the resolution behind the scanning imagery hardware system to motion control arithmetic in X and the Y electric machine controller.

Description of drawings

Fig. 1 is a scanning ultrasonic microscope agent structure synoptic diagram;

Fig. 2 is the motion control block diagram of motor on the XY scanning platform among the present invention;

Fig. 3 is the track while scan synoptic diagram of traditional grid scan pattern of the present invention;

Fig. 4 is the track while scan synoptic diagram of the quick grid scan pattern based on twin shaft interlock of the present invention;

Fig. 5 be the scanning ultrasonic microscope the scanning of traditional grid with under the grid scan pattern same coin is carried out result's contrast of scanning imagery fast.

Embodiment

Scanning ultrasonic microscope fast scanning method based on the twin shaft interlock; Adopt the scanning ultrasonic microscope, the scanning ultrasonic microscope comprises ultrasonic probe, X spindle motor, y-axis motor, Z spindle motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, sample to be detected; Sample to be detected is placed in the tank; Ultrasonic probe be located at sample to be detected directly over, the top of ultrasonic probe is connected in the Z spindle motor, the Z spindle motor links to each other with y-axis motor; Y-axis motor links to each other with the X spindle motor; X spindle motor, y-axis motor, Z spindle motor link to each other with electric machine controller, and ultrasonic probe links to each other with ultrasonic transmitter-receiver, and computing machine links to each other with ultrasonic transmitter-receiver, electric machine controller, display respectively; The ultrasonic echo signal of sample to be detected can be converted into corresponding gray-scale map after the signal Processing in computing machine; If will obtain the two dimensional image of whole sample to be detected, then need make ultrasonic probe accomplish scanning through the two-dimentional machinery motion of X spindle motor and y-axis motor to sample to be detected, the step of method is following:

1) after the start of scanning ultrasonic microscope, places sample to be detected, ultrasonic probe emission ultrasound wave;

2) size of scan area S=(Na) * (Na) is set in the computing machine of scanning ultrasonic microscope, wherein N by the resolution of one-tenth image, a is the size of single pixel;

3) y-axis motor is moved along positive dirction; The X spindle motor moves along negative direction; Making

is the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish a line scanning to sample to be detected;

4) after line scanning finishes; Changing y-axis motor direction of motion then is negative direction; X spindle motor direction of motion is constant; And make

and be the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finishes; Changing X spindle motor direction of motion again is positive dirction; Y-axis motor direction of motion is negative direction not yet; Making

is the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish the line scanning again to sample to be detected;

6) after line scanning finishes again; And then change X spindle motor direction of motion is negative direction; Y-axis motor direction of motion is constant; And make

and be the size of X sample to be detected and y-axis motor moving displacement; X sample to be detected and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), sample to be detected is come flyback retrace, until the entire image been scanned.

For the zone of scan area S=(Na) * (Na), face the scan efficiency of the fast scanning method of traditional grating lattice scan method and the present invention proposition down and make comparison.

1) traditional grid scan method:

The track while scan of tradition grid scan method is as shown in Figure 3, and the X spindle motor is responsible for line scanning, and y-axis motor is responsible for stepping.The Theoretical Calculation expression formula of the T.T. of scanning is:

T ₁＝N·t _{scan_1}+(N-1)·t _{step_1} (1)

, t wherein _{Scan_1}And t _{Step_1}Be respectively a line scanning and once used time of stepping.Suppose to adopt in X and the y-axis motor controller T-shape velocity diagram to carry out interpolation, a _mAnd v _mBe respectively acceleration and maximal rate that X and y-axis motor kinematic system are allowed.Have in line scanning when generally carrying out the large tracts of land imaging to have the uniform motion stage, assurance

guarantees to exist in the stepping process the at the uniform velocity stage but when resolution is very high, differ surely.So:

$t_{\mathrm{scan}\_1}=\frac{v_m}{a_m}+\frac{(N-1)a}{v_m}---\left(2\right)$

$t_{\mathrm{step}\_1}=\left\{\begin{array}{cc}\frac{a}{v_m}+\frac{v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ 2\sqrt{\frac{a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right.,---\left(3\right)$

With getting in equation (2) and (3) substitution (1):

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="120223153235.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\left\{\begin{array}{cc}\frac{(N^2-1)a}{v_m}+\frac{(2N-1)v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \frac{N(N-1)a}{v_m}+\frac{{\mathrm{Nv}}_m}{a_m}+2(N-1)\sqrt{\frac{a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right..---\left(4\right)$

When N＞＞1, have:

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="120223153235.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{(N^2-1)a}{v_m}---\left(5\right)$

2) fast scanning method of the present invention's proposition:

The track while scan of the fast scanning method that the present invention proposes is as shown in Figure 4, and X axle and y-axis motor are responsible for line scanning and stepping simultaneously, and the Theoretical Calculation expression formula of the T.T. of scanning is:

T ₂＝N·t _{scan_2}+(N-1)·t _{step_2} (6)

, t wherein _{Scan_2}And t _{Step_2}Be respectively a line scanning and once used time of stepping.Suppose to adopt in X and the y-axis motor controller T-shape velocity diagram to carry out interpolation, a _mAnd v _mBe respectively acceleration and maximal rate that X and y-axis motor kinematic system are allowed.Generally carrying out the large tracts of land imaging time has

X and y-axis motor have the uniform motion stage in scanning, and assurance

guarantees to exist in the stepping process the at the uniform velocity stage but when resolution is very high, differ surely.So:

$t_{\mathrm{scam}\_2}=\frac{v_m}{a_m}+\frac{(N-1)a}{\sqrt{2}{v}_m}---\left(7\right)$

$t_{\mathrm{step}\_2}=\left\{\begin{array}{cc}\frac{a}{\sqrt{2}{v}_m}+\frac{v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \sqrt{\frac{2\sqrt{2}a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right.,---\left(8\right)$

With getting in equation (2) and (3) substitution (1):

$T_2=\left\{\begin{array}{cc}\frac{(N^2-1)a}{\sqrt{2}{v}_m}+\frac{(2N-1)v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \frac{N(N-1)a}{\sqrt{2}{v}_m}+\frac{{\mathrm{Nv}}_m}{a_m}+(N-1)\sqrt{\frac{2\sqrt{2}a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right..---\left(9\right)$

When N＞＞1, have:

$T_2=\frac{(N^2-1)a}{\sqrt{2}{v}_m}---\left(10\right)$

At this moment;

is that the fast scanning method that the present invention proposes is compared with traditional grid scan method; Can improve sweep speed 29%, scan efficiency is significantly improved.

Below in conjunction with embodiment and accompanying drawing the present invention is done further and to be described in detail.

As sweep object, scan area S is 20 * 20mm with the monobasic Renminbi coin ², be under 512 * 512 the situation in image resolution ratio, N=512, a=39.06 μ m.The fast scanning method that uses traditional grid scan method and the present invention to propose carries out scanning imagery to above-mentioned zone.

The execution in step of tradition grid scan method is following:

1) after the scanning ultrasonic microscope start, confirms motor advance step-length a=39.0625 μ m and scanning area 20 * 20mm through Control Software ²(N=512);

2) ultrasonic probe is moved to the top of monobasic coin, use self-focusing control system control ultrasonic probe and measured material relative position;

3) according to track while scan setting in motion shown in Figure 3, make the X spindle motor along the positive dirction 19.96mm that moves, the X spindle motor stops the back y-axis motor along negative direction stepping 39.06 μ m;

4) make the X spindle motor along the negative direction 19.96mm that moves again, the X spindle motor stops the back y-axis motor again along negative direction stepping 39.06 μ m;

5) repeat 3) to 4) in step, whole by the scanning of scanning area until accomplishing to coin;

6) when the X spindle motor carries out line scanning each time; Grating signal triggering high-speed AD card by the X spindle motor comes acquisition pulse formula ultrasonic echo signal; Computing machine will be handled and feature extraction echoed signal; And be converted into the gradation of image value at this some place, and the image that obtains is shown in Fig. 5 (a), and be 544s whole sweep time.

The execution in step of the fast scanning method that the present invention proposes is following:

1) after the scanning ultrasonic microscope start, place the monobasic coin, ultrasonic probe is moved to the top of monobasic coin, ultrasonic probe emission ultrasound wave uses self-focusing control system control ultrasonic probe and coin relative position;

2) in scanning ultrasonic microscope software, scan area S=(Na) * (Na)=20 * 20mm is set ², wherein N=512 by the resolution of one-tenth image, a=39.06 μ m is the size of single pixel.

3) the motion control block diagram of X spindle motor and y-axis motor is as shown in Figure 2; The control mode that adopts feed-forward loop to combine with PID position feedback, velocity feedback; To improve the track following performance of scan module; According to track while scan setting in motion shown in Figure 4; Y-axis motor is moved along positive dirction, and the X spindle motor moves along negative direction, makes

be the size of X and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X spindle motor and y-axis motor makes ultrasonic probe in the XY plane, accomplish a line scanning to coin;

4) changing y-axis motor direction of motion then is negative direction; X spindle motor direction of motion is constant; And make

and be the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X spindle motor and y-axis motor makes probe do micro-stepping;

5) changing X spindle motor direction of motion again is positive dirction, and y-axis motor direction of motion is negative direction not yet, makes L _Scan=14.12mm is the size of X spindle motor and y-axis motor moving displacement, and X spindle motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X spindle motor and y-axis motor makes probe in the XY plane, accomplish the line scanning again to sample;

6) and then to change X spindle motor direction of motion be negative direction; Y-axis motor direction of motion is constant; And make and be the size of X spindle motor and y-axis motor moving displacement; X spindle motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X spindle motor and y-axis motor makes probe do micro-stepping;

7) repeat 3) to 6) in step, flyback retrace is come in coin zone to be detected, until the entire image been scanned.The image that obtains is shown in Fig. 5 (b), and be 402s whole sweep time, compares with traditional grid scan method, improves sweep speed 26.1%.

As can beappreciated from fig. 5 the fast scanning method of the present invention's proposition can't influence the quality of image to some extent, but because the resultant velocity that has utilized X spindle motor and y-axis motor to move simultaneously, fast scanning method proposed by the invention can be realized scanning faster.

Claims (1)

1. scanning ultrasonic microscope fast scanning method based on twin shaft interlock; Adopt the scanning ultrasonic microscope, the scanning ultrasonic microscope comprises ultrasonic probe, X spindle motor, y-axis motor, Z spindle motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, sample to be detected; Sample to be detected is placed in the tank, ultrasonic probe be located at sample to be detected directly over, the top of ultrasonic probe is connected in the Z spindle motor; The Z spindle motor links to each other with y-axis motor; Y-axis motor links to each other with the X spindle motor, and X spindle motor, y-axis motor, Z spindle motor link to each other with electric machine controller, and ultrasonic probe links to each other with ultrasonic transmitter-receiver; Computing machine links to each other with ultrasonic transmitter-receiver, electric machine controller, display respectively, it is characterized in that the step of method is following:

1) after the start of scanning ultrasonic microscope, places sample to be detected, ultrasonic probe emission ultrasound wave;

2) in the computing machine of scanning ultrasonic microscope, scan area is set S=( Na) * ( Na) size, wherein NBy the resolution of one-tenth image, aSize for single pixel;

3) y-axis motor is moved along positive dirction, the X spindle motor moves along negative direction, order L _Scan =( N-1) A/

Be the size of X spindle motor and y-axis motor moving displacement, X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish a line scanning to sample to be detected;

4) after line scanning finished, changing y-axis motor direction of motion then was negative direction, and X spindle motor direction of motion is constant, and order L _Step = a/

Be the size of X spindle motor and y-axis motor moving displacement, X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finished, changing X spindle motor direction of motion again was positive dirction, and y-axis motor direction of motion is negative direction not yet, order L _Scan =( N-1) A/

Be the size of X spindle motor and y-axis motor moving displacement, X spindle motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in the XY plane, accomplish the line scanning again to sample to be detected;

6) after line scanning finishes again, and then to change X spindle motor direction of motion be negative direction, and y-axis motor direction of motion is constant, and order L _Step = a/

Be the size of X sample to be detected and y-axis motor moving displacement, X sample to be detected and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), sample to be detected is come flyback retrace, until the entire image been scanned.

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