JPH08110331A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE: To easily improve the image quality by amplifying a reception signal by a suitable amplification factor within a predetermined range to peak detect it, storing the factor with the detected value as one set in an image memory, and correcting the image quality of display data based on them and externally input correction value. CONSTITUTION: A reflected wave component extracted by a gate 8 is input to a variable amplification factor amplifier 9. The amplifier 9 is regulated to a suitable amplification factor in response to the level of the extracted signal, the signal is limited to a signal range for holding high resolution, and output to a peak detector 10. The detector 10 peak detects it, which is digitally converted by an A-D converter 12, and stored as a combination with the factor of the amplifier 9 in an image memory 12. This combination is input from the memory 12 to a display correcting circuit 13, which corrects the display data based on the correction value from a correction vale setter 14. This is input to a display unit 15, and displayed at a position corresponding to an original image. Thus, an expected ultrasonic image can be obtained without regulating a measuring system at each sample 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic microscope capable of forming an ultrasonic image of the surface or internal structure of a sample by using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic wave converged by an acoustic lens is incident on a sample, the reflected wave of the sample is converted into an electric reception signal to extract a necessary reflected wave component, and an ultrasonic image is obtained from the reflected wave component. Ultrasonic microscopes for creating are generally known.

A general ultrasonic microscope measures the intensity of reflected ultrasonic waves from a sample. In such an ultrasonic microscope, in order to obtain an appropriate ultrasonic image, the intensity of the ultrasonic wave incident on the sample is adjusted, the attenuation amount of the received signal of the sample reflected wave is adjusted, or an adjustment combining them is performed. Was.

[0004]

However, since the intensity of the reflected ultrasonic wave from the sample varies depending on the property of the sample, in order to obtain an ultrasonic image having a desired contrast and brightness, the above adjustment is required. Have to master,
There is also a problem that the adjustment requires time and labor.

The present invention has been made in view of the above circumstances, and it is possible to obtain an expected ultrasonic image without adjusting the measurement system corresponding to each sample, and it is possible for an expert to know. Provides an ultrasonic microscope that can easily obtain an ultrasonic image with the expected image quality without using it, and that can form an ultrasonic image with a detection value that maintains a predetermined number of effective digits regardless of the magnitude of reflected ultrasonic waves. The purpose is to do.

[0006]

The present invention has taken the following means in order to achieve the above object. The present invention corresponding to claim 1 is characterized in that an ultrasonic wave converged by an acoustic lens is incident on a sample, a reflected wave from the sample is received and converted into an electrical received signal, and an ultrasonic wave is detected according to the intensity of the received signal. In an ultrasonic microscope that forms a sonic image, an amplification circuit that changes the amplification factor so that the reception signal has a size within a predetermined range, and amplifies the reception signal with an appropriate amplification factor according to the intensity, and the amplification circuit. An image in which a peak detection circuit for peak-detecting the received signal amplified by, a detection value of the received signal peak-detected by the peak detection circuit, and an amplification factor of the received signal in the amplification circuit are recorded as one set. A memory and a display correction circuit that corrects the image quality of the display data based on a detection value and an amplification factor stored in the image memory and a correction value input from the outside are provided.

According to a second aspect of the present invention, in the ultrasonic microscope having the above structure, the display correction circuit has display data larger than the maximum value P or smaller than the minimum value in one screen. In this case, a correction value for changing the display data to the maximum value or the minimum value is calculated, and the display data is corrected using the correction value.

[0008]

The present invention has the following effects by taking the above measures. According to the present invention corresponding to claim 1, the electrical reception signal of the reflected ultrasonic waves received by the acoustic lens is amplified (attenuated) by the amplification circuit so as to have a magnitude within a predetermined range, and the amplification circuit is used. The amplified received signal is subjected to peak detection by the peak detection circuit. The detection value of the reception signal peak-detected by the peak detection circuit and the amplification factor of the reception signal in the amplification circuit are recorded as a set in the image memory. In the display correction circuit, the pixel data is restored from the detection value and the amplification factor stored in the image memory, and the image data such as contrast and brightness of the pixel data is corrected based on the correction value input from the outside.

Therefore, it is possible to significantly limit the dynamic range of the received signal and to perform image quality adjustment without using an image quality adjustment circuit whose adjustment operation is complicated. In addition, even when a sample with a large difference in reflection intensity is to be observed, the magnitude of the received signal is set within the range that allows the highest resolution, and the display data is calculated from the amplification factor and signal value (peak detection value) at that time. Since it can be reproduced, the number of effective digits of the signal value can be maintained without being affected by the intensity of the reflected ultrasonic wave.

According to the second aspect of the present invention, the maximum value of pixel data that can be satisfactorily displayed without being saturated and the minimum value of pixel data that can be displayed are set or input to the display correction circuit. It Then, when there is display data larger than the maximum value in one screen, a correction value for changing the display data to the maximum value is calculated. Similarly, when there is display data smaller than the minimum value in one screen, a correction value for changing the display data to the minimum value is calculated. Then, the display data obtained by applying the above-described correction to the display data of the screen can be reproduced to display the screen.

[0011]

Embodiments of the present invention will be described below. FIG. 1 shows the configuration of an ultrasonic microscope according to an embodiment of the present invention. The ultrasonic microscope of the present embodiment includes a pulse transmitter 1 that outputs a transmission pulse, a transducer 2 that converts a transmission pulse applied from the pulse transmitter 1 into an ultrasonic wave, and an ultrasonic wave generated by the transducer 2 An ultrasonic wave transmitting / receiving unit is configured by the acoustic lens 3 and the like that converge on a spot. The sample 5 is installed in the water tank 4 arranged within the scanning range of the acoustic lens 3, and the acoustic lens 3 and the sample 5
Between them is filled with a coupler liquid 6 for propagating ultrasonic waves.

The ultrasonic wave that has entered the sample 5 is reflected and again enters the acoustic lens 3, passes through the lens and is applied to the transducer, where it is converted into an electrical reception signal and then input to the preamplifier 7. .

A gate unit 8 for extracting a signal component in an arbitrary section from a received signal is connected to the output stage of the preamplifier 7, and a variable amplification factor amplifier 9 is connected to the output stage of the gate unit 8. The variable amplification factor amplifier 9 changes the amplification factor according to the amplitude of the received signal so that the received signal has a size within a predetermined range. A peak detection circuit 10 is connected to the output stage of the variable amplification factor amplifier 9. Peak detection circuit 1
0 is connected to the A / D converter 11. The output of the A / D converter 11 and the amplification factor of the variable amplification factor amplifier 10 are stored in the image memory 12 as a set. The detection value and the amplification factor stored in the image memory 12 are output to the display correction circuit 13 in synchronization with the display timing. Display correction circuit 1
In No. 3, the correction value input from the correction value setting unit 14 and the detection value and the amplification factor input from the image memory 12 are processed based on a predetermined function to optimize the image quality such as contrast and brightness. The display data is output to the display unit 15. In the correction value setting unit 14, the operator manually sets the contrast, brightness, gamma correction, and other correction values of the display image that differ depending on the sample. The operator can arbitrarily set these correction values.

The CPU 16 manages the oscillation timing of the transmission pulse from the pulse transmission unit 1 and the ultrasonic scanning. The CPU 16 gives a timing signal to the scanning units 17 to 19 which perform scanning in the X, Y, and Z directions orthogonal to each other, and outputs a transmission command to the pulse control unit 20. Further, the gate section 8 is controlled in the gate period by the gate control circuit 21. Alternatively, the correction value in the initial state may be fixed or automatically set without particularly adjusting the correction value setting unit 14.

This is to use the correction value that the correction value setting section 14 has at the time of initial setting. The initial setting value is the average or mode of the correction values on the display screen, which is a value that those skilled in the art frequently use. Often used. In other words,
The initial setting value is a value that is considered to be optimal as a correction value.

The scanning units 17 to 19 are provided with the acoustic lens 3
And the sample 5 are changed. Generally, the acoustic lens 3 is oscillated in one direction of X or Y, and the sample 5 is moved in the other direction of one of X and Y in a sample holding stage (not shown). (1) moves one plane of the sample. Also. Generally, the sample can be moved in the Z-axis direction.

However, as described above, the acoustic lens 3 and the sample 5 are
There are several methods of relatively changing the relationship between the sample and the sample holding stage in the X, Y, and Z directions. Amplitude and a method of moving the whole (not shown) may be mentioned. Further, as long as the amplitude and movement are possible in the X, Y, and Z directions, and the relationship between the acoustic lens 3 and the sample 5 is relatively changed in the same manner as described above, a method other than the above-mentioned method is used. It may be.

Next, the operation of the embodiment constructed as described above will be described. First, the CPU 16 scans the sample 5 with ultrasonic beams at predetermined intervals so that X, Y, and Z are scanned.
The scanning units 17 to 19 in the direction are controlled, and a transmission command is issued to the pulse control unit 20 in synchronization with the scanning timing.

A transmission trigger is output from the pulse control unit 20 to the pulse transmission unit 1 starting from the transmission command, and a single pulse signal is input from the pulse transmission unit 1 to the transducer 2 via the circulator. Transducer 2
The pulse signal is converted into an ultrasonic wave by the electroacoustic conversion by the ultrasonic wave, and the ultrasonic wave is converged by the acoustic lens 3 and enters the sample 5 as a minute spot.

The reflected wave from the sample 5 is again received by the acoustic lens 3, propagates in the lens, and then is transferred to the transducer 2.
Is converted into an electrical reception signal by. This received signal is input to the preamplifier 7 through the circulator and amplified to a predetermined level. The amplified reception signal is applied to the gate unit 8
To enter.

On the other hand, the gate control circuit 21 generates a gate control signal for applying a gate to an arbitrary position with respect to the received signal corresponding to the transmission pulse transmitted to the transducer 2 and supplies it to the gate section 8. The gate unit 8 opens the gate based on the gate control signal input from the gate control circuit 21, and extracts an arbitrary signal component from the received signal input from the preamplifier 7. The reflected wave component (extracted signal) extracted by the gate unit 8 is input to the variable amplification factor amplifier 9.

The variable amplification factor amplifier 9 adjusts the amplification factor to an appropriate amplification factor according to the signal level of the extraction signal and narrows down the extraction signal to a signal range capable of realizing high resolution. The extracted signal after this amplification is output to the peak detection circuit 10, and the amplification factor at that time is output to the image memory 12.

For example, the extraction signal M (= A from the gate unit 8
X 10 ^B ), the extracted signal M is (A
Amplify (attenuate) to × 10 ^B ) / 10 ^B , output the amplified (attenuated) extracted signal (= A) to the peak detection circuit 10, and output the decibel-displayed amplification factor B to the image memory 12. To do. That is, although the magnitude of the extraction signal M varies greatly depending on the sample, the amount of attenuation (= 1
0 ^B ) is adjusted. Here, 10 ^B is used as the attenuation amount, but the expression of the attenuation amount is not particularly limited to this, and the expression of a value suitable for each occasion such as 9 ^B and 8 ^B can be made according to the sample and the measurement conditions. You can use it.

The extracted signal A is subjected to peak detection by the peak detection circuit 10, and the detected value A is converted into digital data by the A / D converter 11. Then, the detection value A output from the A / D converter 11 and the amplification factor B in the variable amplification factor amplifier 9 of the extracted signal corresponding to the detection value A are stored in the image memory 12 as a set.

Such an operation is repeated during each ultrasonic wave transmission / reception during the scanning period for one screen, and the set of the detection value A and the amplification factor B is sequentially stored in the image memory 12. On the other hand, the set of the detection value A and the amplification factor B stored in the image memory 12 is input from the image memory 12 to the display correction circuit 13 in accordance with the display timing of each point forming the screen. The display correction circuit 13 uses the correction value Fs from the correction value setting unit 14 and the detection value A and the amplification factor B from the image memory 12 to display the display data Pi by a function of Pi = S (Fs, A, B). Ask. This display data Pi is input to the display unit 15 and displayed at a predetermined pixel position corresponding to the original image.

The initial setting value is used as the correction value Fs for the first screen, and the image corrected with the initial setting value is displayed on the display unit 15. The operator determines the contrast, brightness, etc. of the image displayed on the display unit 15, and feeds back the correction value setting unit 14 so that they are optimal. The initial setting value of the correction value Fs includes correction value = 0.

Further, the display correction circuit 13 has a maximum value Pmax of pixel data which can be displayed well without being saturated in the display section 15,
And the minimum value Pmin of pixel data that can be displayed on the display unit 15.
Is set. When there is display data Pi larger than the maximum value Pmax in one screen, a correction value for changing the display data Pi to the maximum value Pmax is calculated. Similarly, when there is display data Pi smaller than the minimum value Pmin in one screen, a correction value for changing the display data Pi to the minimum value Pmin is calculated. And
On the next screen, the display data Pi converted by using the calculated correction value Fs is suppressed between the upper limit level and the lower limit level of the display unit 15. As a result, a screen in which the display data Pi is suppressed between the upper limit level and the lower limit level of the display unit 15, that is, an image obtained by correcting the previous screen is displayed on the display unit 1.
5 can be displayed.

The display data Pi corrected by the display correction circuit 13 is sequentially passed to the display unit 15 and displayed. As described above, according to this embodiment, the amplification factor B of the variable amplification factor amplifier 9 to which the reception signal is input is automatically adjusted so that the resolution of the reception signal becomes the highest, and the variable amplification factor amplifier 9 receives the amplified signal. The detection value A and the amplification factor B of the signal are input to the display correction circuit 13 to restore the original pixel data and the contrast and the like are corrected based on the correction value Fs.
Even if the intensity of the reflected ultrasonic wave from the sample varies greatly depending on the sample, the contrast and brightness can be adjusted after the measurement, and the image quality such as contrast and brightness can be easily adjusted.

According to this embodiment, the received signal, which has not been subjected to the contrast and brightness adjustments, is input to the variable amplification factor amplifier 9 so that the effective digit number of the detection value A of the received signal is maintained. Even if the intensities of the reflected ultrasonic waves from A to D vary greatly, it is possible to always ensure a resolution above a certain level.

According to this embodiment, the maximum value Pmax and the minimum value Pmin of the pixel data are set in the display correction circuit 13, and the display data Pi larger than the maximum value Pmax or the display smaller than the minimum value Pmin is displayed in one screen. If the data Pi exists, the display data is set to the maximum value Pmax or the minimum value P.
The correction value for changing to min is calculated, and after that, the correction value is used to perform data correction, so it is possible to secure a good ultrasonic image even when the pixel data is saturated. it can. The present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

[0031]

As described in detail above, according to the present invention, an expected ultrasonic image can be obtained without adjusting the measurement system corresponding to each sample, and it is possible to obtain it without depending on a skilled person. It is possible to provide an ultrasonic microscope capable of easily obtaining an ultrasonic image having the expected image quality and capable of forming an ultrasonic image with a detection value that maintains a predetermined number of effective digits regardless of the magnitude of reflected ultrasonic waves.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ultrasonic microscope according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pulse transmission part, 2 ... Transducer, 3 ... Acoustic lens, 8 ... Gate part, 9 ... Variable amplification factor amplifier, 10 ... Peak detection circuit, 12 ... Image memory, 13 ... Display correction circuit, 14 ... Correction value setting part , 15 ... Display section.

Claims (2)

[Claims] 1. An ultrasonic wave converged by an acoustic lens is incident on a sample, a reflected wave from the sample is received and converted into an electrical reception signal, and an ultrasonic image is formed by the intensity of the reception signal. In an ultrasonic microscope, the amplification factor changes so that the received signal has a magnitude within a predetermined range, and an amplification circuit that amplifies the received signal with an appropriate amplification factor according to its intensity, and a reception signal amplified by the amplification circuit. A peak detection circuit for peak detection of a signal, an image memory in which the detection value of the received signal peak-detected by the peak detection circuit and the amplification factor of the received signal in the amplification circuit are recorded as one set, and the image An ultrasonic microscope, comprising: a display correction circuit that corrects the image quality of display data based on a detection value and an amplification factor stored in a memory and a correction value input from the outside. 2. The display correction circuit sets a maximum value and a minimum value of display data, and when there is display data larger than the maximum value P or smaller than the minimum value in one screen, The ultrasonic microscope according to claim 1, wherein a correction value for changing the display data to the maximum value or the minimum value is calculated, and the display data is corrected using the correction value.