CN101692069B - Construction method of C scanning TOF image of ultrasonic scanning microscope - Google Patents

Abstract

The invention provides a construction method of a C scanning TOF image of an ultrasonic scanning microscope, which relates to the technical field of ultrasonic scanning microscope equipment for processing the acquired data. The method comprises the following steps: a. setting a C scanning data gate to determine a detection area and threshold voltage; b. scanning and emitting ultrasonic waves, andusing a grating ruler for synchronous position triggering to generate the ultrasonic waves to extract the time of each point in the data gate area when a return signal reaches a peak value (i.e. peaktime); and c. carrying out data processing on the peak time of the point; and d. outputting a gray value corresponding to each point onto a screen to construct a gray image. The invention overcomes the defect that the software triggering position is inaccurate in the prior art, has the advantages of accurate position of the constructed image, high precision and the like, can overcome the defects that the algorithm has higher requirements on the surface flatness and arrangement of a measured object and the obtained peak time is inaccurate, improves the construction speed of the image, and obtains a clear constructed scanning image which can reflect the characteristic of the depth direction of a device in detail.

Description

The construction method of C scanning TOF image of ultrasonic scanning microscope

Technical field

The present invention relates to the technical field of data processing of ultrasonic scanning microscope device to collecting, especially a kind of C scanning TOF picture construction method.

Background technology

Along with the production scale of electronic product is increasing, kind is more and more, the integrated degree of circuit and production automation degree also improve accordingly, quality requirements to device is also more and more higher simultaneously, for guaranteeing device reliability, it is indispensable flow process that packaged device is carried out Non-Destructive Testing, detects the defectives such as insensitive layering, cavity, crack and uses more and more extensive and the ultrasonic scanning microscope can detect X ray.The ultrasonic scanning microscope is by carrying out movement executing mechanism scan axis and cooperating of stepping axle the raster pattern motion, in the scan axis motion, launch ultrasound wave and receive reflection echo, be digital signal with the analog signal conversion of reflection echo, and make up different types of detected image by various transfer algorithms.The microscopical conventional sense mode of ultrasonic scanning comprises A sweep waveform, B scan image, C scanning peak image, C scanning TOF image, C scanning phase reversal image, demixing scan image etc.

C scanning TOF image is the main a kind of detection mode of ultrasonic scanning microscope, it is successively to make up plane picture according to obtaining the reflection echo time to peak, the location drawing that obtains first peak value is higher as grey scale pixel value, the location drawing of rear acquisition peak value is lower as grey scale pixel value, can judge the depth location of detected target by obtaining image, the time of the some explanation transonic that brightness of image is higher is shorter, and is nearer apart from front surface.Existing TOF scan image construction method is: 1, at the A sweep waveform data gate is set, surveyed area and signal threshold value namely are set; 2, when reaching the mode that triggers by software when numerical value is set, position counting triggers hyperacoustic emission in the scanning process, 3, software has a waveform peak time of arrival (toa) to compare the institute in the data gate zone, obtains maximal value and the minimum value of time of arrival.4, take out the time of arrival of the peak value of every bit, and be converted to gray-scale value, and then construct C scanning TOF image.This existing TOF scan image makes up algorithm because ultrasound wave triggers and data acquisition all adopts software to process, trigger position is not accurate enough, the time of arrival of the interior every bit peak value of surveyed area is also inaccurate, and because the software data processing amount is large, causes picture construction speed slow.

Summary of the invention

The construction method that the purpose of this invention is to provide a kind of C scanning TOF image of ultrasonic scanning microscope, the grating scale sync bit triggering for generating ultrasound wave that adopts has solved the inaccurate shortcoming of software trigger position in the prior art, have the design of graphics image position accurately, the precision advantages of higher.As adopt front surface to follow technology, can separate annual reporting law peak value inaccurate shortcoming time of arrival is had relatively high expectations, obtained to measured target surface planarity and placement; As adopt hardware to differentiate peak value, and return the method for positive negative peak and the positive and negative time to peak value of arrival, can reduce the software data processing amount, improved picture construction speed.

This main technical schemes of the present invention is: a kind of construction method of C scanning TOF image of ultrasonic scanning microscope is characterized in that having following steps:

A, the C scan data gate is set, to determine surveyed area and threshold voltage:

B, scanning and emitting ultrasonic waves: in the scanning process each above-mentioned location point is launched ultrasound wave, the grating scale sync bit triggering for generating ultrasound wave that adopts: namely adopt grating scale as feedback assembly, automatic hardware trigger produces ultrasound wave when the grating scale counting reaches the value of pre-seting, and reception reflection echo, adopt hardware to differentiate peak value, extract the time that each some return signal in the data gate zone arrives peaking, i.e. time to peak;

C, the time to peak of this point is done data process, convert corresponding gray-scale value to according to certain method: if positive peak and negative peak all find simultaneously, the order of magnitude that compares again them, that peak value that absolute value is larger is converted into corresponding gray-scale value as time to peak time of arrival; If only find one in the positive negative peak, then with time of arrival of this peak value as time to peak, be converted into corresponding gray-scale value; If positive negative peak does not all find, and is 0 with this gray-scale value assignment directly then.

D, the gray-scale value that each point is corresponding output to and make up gray level image on the screen.

In the described a step, can adopt front surface to follow technology: the front surface data gate is set, obtains front surface reflection echo negative peak time coordinate, the time coordinate that data gate is set is the relative coordinate of front surface reflection echoed signal negative peak time coordinate.

In the described b step, the positive negative peak in the return data door is worth in time, reduces the software data processing amount.

In the described b step, the time of record measured target front surface reflection echo negative peak, and should the time as reference time of data gate, the zero-time of data gate is the relative value of this time, solve because measured target surface irregularity or placement tilt to cause data gate that inaccurate problem is set, solved acquisition peak value inaccurate problem time of arrival.

In the described c step, described final time to peak is converted to design of graphics: for each point in the scanning area, time to peak to this point is processed, can be divided into following several situation: 1. positive negative peak all finds (as shown in Figure 3), relatively positive peak absolute value and negative peak absolute value are got that larger return signal peak value value time of arrival and are time to peak; 2. only just (bearing) peak value and finding (shown in Fig. 4 (5)), with time of arrival of this peak value as time to peak; 3. positive negative peak does not all find (as shown in Figure 6), and then directly returning this pixel value gray scale is 0.If time to peak called after t extracts have a few final return signal time to peak in the data gate zone in the scanning area, obtain this and have a few middle time to peak maximal value t _MaxWith minimum value t _Min, the gradation of image value G that peaking time t is corresponding, calculate according to following formula:

$G=\frac{t_{\max }-t}{t_{\max }-t_{\min }}\×255.$

Good effect of the present invention is: contrast with prior art, the present invention has adopted grating scale sync bit triggering for generating ultrasound wave to solve that the medium-term and long-term people of existence of prior art want to solve always and the inaccurate problem of unsolved software trigger position always, have the design of graphics image position accurately, the precision advantages of higher.Adopt front surface to follow technology, can separate annual reporting law peak value inaccurate shortcoming time of arrival is had relatively high expectations, obtained to measured target surface planarity and placement; Adopt hardware to differentiate peak value, return the method for positive negative peak and the positive and negative time to peak value of arrival, can reduce the software data processing amount, improved picture construction speed.Solved existing method to measured target surface planarity and placement require high, the design of graphics image position is inaccurate, return signal peak value time of arrival is inaccurate, structure speed waits problem slowly, the scan image that makes up is clear, the feature of reflection device depth direction that can be detailed, thus precision, accuracy and the speed of picture construction guaranteed.

Description of drawings

Fig. 1 is the schematic diagram that the front surface door is set at the A sweep waveform.

Fig. 2 is the schematic diagram that data gate is set at the A sweep waveform.

Fig. 3 is the schematic diagram that positive negative peak all finds.

Fig. 4 is the schematic diagram that finds of positive peak only.

Fig. 5 is the schematic diagram that finds of negative peak only.

Fig. 6 is the schematic diagram that positive negative peak does not all find.

Fig. 3～6 all are the peak value estimate of situations of simple declaration TOF scan data gate.Data gate all represents with the rectangular area among the figure, and the left margin Far Left of rectangle and the right are along the start time and the concluding time that represent respectively data gate, and the upper edge of rectangle and lower edge represent respectively the positive negative threshold voltage of data gate.

Embodiment

(referring to Fig. 1～Fig. 6) and preferred embodiment the present invention is described in further detail, but not as a limitation of the invention below in conjunction with accompanying drawing.

The performing step of this embodiment structure algorithm is as follows:

1. as shown in Figure 1, adjust the position of ultrasonic probe, observe the A sweep waveform, probe is focused on the depth location of detected target, in front surface reflection echo region division front surface data gate.

2. as shown in Figure 2, detecting target location reflection echo region division C scan data gate, the C scan data gate adopts rectangle to represent, what need to prove the extraction of the C of TOF use here scan data gate is that reflected signal is to the time of peaking.

3. scanning area is set, begins to scan from reference position, the ultrasound wave sending and receiving apparatus is counted the grating scale signal in the scanning process, produces ultrasound wave when counting reaches the value of pre-seting.

4. record the time of measured target front surface reflection echo negative peak, and should the time as reference time of data gate, the zero-time of data gate is the relative value of this time, solve because measured target surface irregularity or placement tilt to cause data gate that inaccurate problem is set, solved acquisition peak value inaccurate problem time of arrival.

5. for each point in the scanning area, time to peak to this point is processed, can be divided into following several situation: 1. positive negative peak all finds (as shown in Figure 3), and relatively positive peak absolute value and negative peak absolute value are got that larger return signal peak value value time of arrival and be time to peak; 2. only just (bearing) peak value and finding (shown in Fig. 4 (5)), with time of arrival of this peak value as time to peak; 3. positive negative peak does not all find (as shown in Figure 6), and then directly returning this pixel value gray scale is 0.For convenient follow-up explanation, for the time being time to peak called after t.

6. according to the algorithm of step 5, extract have a few time to peak in the data gate zone in the scanning area, obtain the maximal value t that this has a few middle time to peak _MaxWith minimum value t _Min

7. the gradation of image value G that peaking time t is corresponding, calculate according to following formula:

$G=\frac{t_{\max }-t}{t_{\max }-t_{\min }}\×255$

For example: in certain surveyed area, the maximal value of returning time to peak and the minimum value that obtain in this zone are respectively: t _Max=1.2us, t _Min=0.2us, certain any time to peak t value is 0.8us.The gray-scale value of the gray level image that this point is corresponding so is:

$G=\frac{t_{\max }-t}{t_{\max }-t_{\min }}\×255=\frac{1.2-0.8}{1.2-0.2}\×255=0.4\×255=102$

8. obtain the gradation of image value of each point of measured target surveyed area by above step, these pixels are arranged in order, realize the structure of C scanning TOF image.

Claims (5)

1. the construction method of a C scanning TOF image of ultrasonic scanning microscope is characterized in that having following steps:

A, the C scan data gate is set, with specified data door surveyed area and threshold voltage, adopt front surface to follow technology: the front surface door is set, obtain front surface reflection echo negative peak time coordinate, the time coordinate that the C scan data gate is set is the relative coordinate of front surface reflection echo negative peak time coordinate;

B, scanning and emitting ultrasonic waves: in the scanning process each location point in the scanning area is launched ultrasound wave, the grating scale sync bit triggering for generating ultrasound wave that adopts: namely adopt grating scale as feedback assembly, automatic hardware trigger produces ultrasound wave when the grating scale counting reaches the value of pre-seting, and reception reflection echo, extract the return signal of each location point in the data gate surveyed area in the scanning area to time of peaking, i.e. time to peak;

C, the time to peak of each location point in the scanning area is done data process, gray-scale value corresponding to time to peak convert to according to certain method: if positive peak and negative peak all find, relatively positive peak absolute value and negative peak absolute value, getting that larger return signal is time to peak to the time value of peaking; If only positive peak or negative peak find, this return signal is arrived the time of peaking as time to peak; If positive peak and negative peak all do not find, be 0 with this gray-scale value assignment directly then;

D, the gray-scale value that each point is corresponding output to and make up gray level image on the screen.

2. the construction method of C scanning TOF image of ultrasonic scanning microscope according to claim 1, it is characterized in that in the b step of described claim 1, adopt grating scale sync bit triggering for generating ultrasound wave: namely adopt grating scale as feedback assembly, when the grating scale counting reached the value of pre-seting, hardware trigger produced ultrasound wave automatically.

3. the construction method of C scanning TOF image of ultrasonic scanning microscope according to claim 1 is characterized in that in the described b step, adopts hardware to differentiate peak value, and the positive negative peak in the return data door is worth in time, reduces the software data processing amount.

4. the construction method of C scanning TOF image of ultrasonic scanning microscope according to claim 1, it is characterized in that in a step of described claim 1, the time of record measured target front surface reflection echo negative peak voltage, and should the time as reference time of C scan data gate, the zero-time of C scan data gate is for take the front surface reflection echo negative peak voltage relative time as zero point of time of arrival.

5. the construction method of C scanning TOF image of ultrasonic scanning microscope according to claim 1, it is characterized in that in the described c step, described time to peak is converted to design of graphics: the crest voltage for each location point in the scanning area is processed, and can be divided into following several situation: Positive peak and negative peak all find, and compare positive peak absolute value and negative peak absolute value, and getting that larger return signal time to peak value is time to peak;

Only positive peak or negative peak find, and this return signal is arrived the time of peaking as time to peak;

Positive peak and negative peak all do not find, and then directly returning this pixel value gray scale is 0, time to peak called after t; Extract the time to peak of each location point in the data gate surveyed area in the scanning area, obtain the maximal value of each the location point time to peak in the scanning area

And minimum value

, the gradation of image value G that peaking time t is corresponding, calculate according to following formula:

G?＝?

?×?255。

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