JP4955381B2 - Ultrasonic imaging method and ultrasonic imaging apparatus - Google Patents

Description

  The present invention relates to an ultrasonic imaging method and an ultrasonic imaging apparatus.

  Conventionally, measurement technology is known in which ultrasonic waves emitted from an ultrasonic transmitter are applied to an object and reflected, the reflected waves are received by the ultrasonic receiver, and the distance to the object is measured by the transmission / reception time and speed of sound. It has been.

  In addition, the reflected wave from the object is received by an ultrasonic array sensor formed by arranging a plurality of ultrasonic receiving elements, and a predetermined calculation process is performed on a signal obtained by each ultrasonic receiving element. A technique for selectively recognizing a reflected wave in a predetermined direction is known (see Patent Document 1). Here, “predetermined arithmetic processing” is performed after delaying a time corresponding to the incident angle of the reflected wave and the positional relationship between the ultrasonic wave receiving elements with respect to the signals obtained by the ultrasonic wave receiving elements. That is. Thereby, it is possible to scan the direction of the reflected wave from the object. By this electronic scanning, information on the three-dimensional position and the three-dimensional shape of the object reflecting the ultrasonic wave can be acquired. From this information, the three-dimensional position and three-dimensional shape of the object reflecting the ultrasonic wave can be imaged.

  By the way, the intensity of the signal obtained by the ultrasonic receiving element is determined by the distance to the object reflecting the ultrasonic wave, the directivity of the ultrasonic receiving element, the reflectance of the object reflecting the ultrasonic wave, and the object reflecting the ultrasonic wave. It varies greatly depending on the incident angle of ultrasonic waves. Therefore, if delay addition or delay multiplication is performed on the signal obtained by the ultrasonic receiving element, the signal strength difference between the signal having a small signal strength and the signal having a large signal is excessively widened, and signal recognition is performed by setting a threshold from the relationship with the noise signal. Then, only signals with high signal strength can be recognized. That is, an object corresponding to a signal having a low signal intensity cannot be recognized.

In order to solve this problem, Patent Document 2 performs the above delay addition on the signal obtained by the ultrasonic receiving element, shows the intensity of the signal obtained as a result for each direction, and further, for each direction. A method is described in which the azimuth of the peak position of the signal intensity is obtained with respect to the signal intensity, and a distance image is generated based on this. According to the method of Patent Document 2, the presence of an object can be recognized even when the intensity of a signal obtained by an ultrasonic receiving element is weak.
JP 2002-156451 A JP 2006-105647 A

  However, with this method, the presence of the object itself can be recognized, but the three-dimensional extent of the object cannot be recognized.

  Accordingly, an object of the present invention is to provide a method and an image for imaging a three-dimensional position and a three-dimensional shape of an object that has reflected ultrasonic waves, even when the intensity of a signal obtained by the ultrasonic receiving element is weak. It is to provide a device for converting.

  Here, the spatial shape means a three-dimensional position and a three-dimensional shape.

According to the first aspect of the present invention, the ultrasonic wave emitted from the ultrasonic wave transmitting element is applied to the object and reflected, and the reflected wave is received by an ultrasonic array sensor in which a plurality of ultrasonic wave receiving elements are arranged. In the ultrasonic imaging method for imaging the spatial shape of the object based on the relationship between the signal intensity obtained by the element and the transmission / reception time, from the received waveform of the signal intensity obtained by each receiving element, (a) (B) calculating a pair of local minimum points at which the signal intensity immediately before and immediately after the n-th position starts from decreasing to increasing; c) a step of storing the received waveform between the pair of minimum points in the storage means as an nth waveform; (d) for the received waveform not stored in the step (c) from the steps (a) to (c); ) Is repeated (N-1) times in the storage means. A step of storing from the first waveform to the Nth waveform, (e) imaging the spatial shape of the object based on the first waveform to the Nth waveform for each receiving element stored in the storage means. Features.

  Here, n is an integer, and is increased from 1 to N in order. n is increased when the steps (a) to (c) are repeated in the step (d).

According to the first aspect of the present invention, it is possible to recognize even a signal waveform having a low signal strength among the received waveforms having a signal strength obtained by the ultrasonic receiving element. The spatial shape can be imaged based on the received waveform.

The invention of claim 2 is characterized in that the value of N is set corresponding to the number of received waveforms in the step (c) that are equal to or greater than a predetermined threshold relating to signal strength.

According to the second aspect of the present invention, only the waveform having a predetermined threshold value or more is recognized among the reception waveforms of the signal intensity obtained by the ultrasonic receiving element. Therefore, it is possible to prevent imaging of a spatial shape of an object that does not actually exist based on noise included in a waveform smaller than a predetermined threshold (a waveform that is not based on ultrasonic waves reflected on the object).

According to a third aspect of the present invention, there is provided a step of correcting the maximum values from the first waveform to the Nth waveform of each receiving element to be equal to each other and storing them in the storage means.

According to the third aspect of the present invention, the maximum value of the received waveform having a low signal strength among the received waveforms of the signal strength obtained by the ultrasonic receiving element has the same signal strength as the maximum value of the received waveform having a high signal strength. Can be corrected as follows. Therefore, a signal with the same signal strength as that of a received waveform with a high signal strength can be obtained after delay addition or delay multiplication even for an object with a received waveform with a low signal strength. Based on this, a spatial shape can be imaged. I can do it.

The invention of claim 4 is characterized in that the number of repetitions of claim 1 is limited so that a disturbance waveform does not enter the received waveform stored in the storage means.

  Here, the disturbance waveform is a so-called noise and is a waveform that is not based on the ultrasonic wave reflected on the object.

According to the invention of claim 4 , since the disturbance waveform is not recognized among the reception waveforms of the signal intensity obtained by the ultrasonic receiving element, the spatial shape of the object that does not actually exist based on the disturbance waveform is imaged. Can be prevented.

In the invention of claim 5, the ultrasonic wave emitted from the ultrasonic wave transmitting element is applied to the object and reflected, and the reflected wave is received by an ultrasonic array sensor formed by arranging a plurality of ultrasonic wave receiving elements. In the ultrasonic imaging apparatus that images the spatial shape of the object based on the relationship between the signal intensity obtained by the element and the transmission / reception time, each receiving element is obtained from the received waveform of the signal intensity obtained by each receiving element. First calculating means for calculating the n-th position where the signal intensity becomes the maximum value every time, and second calculating means for calculating a pair of minimum points at which the signal intensity immediately before and after the n-th position turns from decreasing to increasing, Storage means for storing the received waveform between the pair of local minimum points as an nth waveform, first control means for storing the nth waveform in the storage means, and a received waveform not stored in the step (c). In contrast, from step (a) above ( ) Is repeated (N-1) times to store the first waveform to the Nth waveform in the storage device, and the first waveform to the Nth waveform for each receiving element stored in the storage device. An imaging means for imaging the spatial shape of the object based on the above is provided.

  Here, n is an integer, and is increased from 1 to N in order. n is increased when the steps (a) to (c) are repeated in the step (d).

According to the fifth aspect of the present invention, since a signal waveform having a low signal strength can be recognized among reception waveforms having a signal strength obtained by the ultrasonic wave receiving element, an object having a reception waveform having a low signal strength is also recognized. The spatial shape can be imaged based on the received waveform.

The invention according to claim 6 is characterized by comprising third control means for setting the value of N corresponding to the number of received waveforms in the step (c) that are equal to or greater than a predetermined threshold relating to signal strength.

According to the sixth aspect of the present invention, only a waveform having a signal intensity equal to or higher than a predetermined threshold is recognized among the received waveforms of the signal intensity obtained by the ultrasonic receiving element. Therefore, it is possible to prevent imaging of a spatial shape of an object that does not actually exist based on noise included in a waveform smaller than a predetermined threshold (a waveform that is not based on ultrasonic waves reflected on the object).

The invention according to claim 7 corrects the N-th waveform from the first waveform corrected by the correcting means and the correcting means for correcting the maximum values from the first waveform to the N-th waveform of each receiving element to be equal. It has 4th control means memorize | stored in a memory | storage means, It is characterized by the above-mentioned.

According to the seventh aspect of the present invention, the maximum value of the received waveform having a low signal strength among the received waveforms of the signal strength obtained by the ultrasonic receiving element has the same signal strength as the maximum value of the received waveform having a high signal strength. Can be corrected as follows. Therefore, even for an object with a received waveform with low signal strength, a waveform with the same size as the received waveform with high signal strength can be obtained after delay addition or delay multiplication, and based on this, the spatial shape can be imaged. I can do it.

  According to the present invention, even when the intensity of the signal obtained by the ultrasonic receiving element is weak, the waveform reflected from the object is detected, so that the difference in the reflectance of the object is affected. Without being done, the spatial shape of the object can be imaged.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 schematically shows an example of a waveform of a signal obtained when ultrasonic waves reflected from a target object are received by an ultrasonic receiving element. FIG. 2 is a flowchart showing the procedure of the ultrasonic imaging method according to the present invention. Hereinafter, a method of imaging a signal obtained when received by an ultrasonic wave receiving element will be described with reference to the reception waveform of FIG. 1 according to the flowchart of FIG.

  First, the imaging method starts. In step S1, the contents of the storage means are reset (initialized). In step S2, the received waveform obtained by the ultrasonic receiving element is converted into digital data by the AD conversion means and stored in the storage means. In step S3, the variable n is set to 1. The variable n is an integer, and is used to name and identify the divided received waveforms stored in the storage means in step S2.

  In step S4, it is determined whether waveform information other than the received waveform stored in step S2 is stored in the storage unit. If NO (no waveform information other than the received waveform stored in step S2 is stored in the storage means), the process proceeds to step S5. If YES (the waveform information other than the received waveform stored in step S2 is stored in the storage means), the process proceeds to step S12. At the beginning (when n = 1), since the contents of the storage means are reset (initialized) in step S1, there is no waveform information in the storage means other than the received waveform stored in the storage means in step S2 ( Since the determination in step S4 is NO), the process proceeds to step S5.

  In step S5, the nth position Pn (P1 when n = 1 in FIG. 1) where the signal intensity is maximum is detected by calculation in the received waveform stored in the storage means.

  Next, in step S6, it is determined whether the signal intensity at the nth position Pn is greater than or equal to a predetermined threshold value. If YES (the signal intensity at the nth position Pn is greater than or equal to a predetermined threshold value), the process proceeds to step S7. If NO (the signal intensity at the nth position Pn is not equal to or greater than the predetermined threshold value), the process proceeds to step S13. Here, as YES (the signal intensity at the n-th position Pn is greater than or equal to a predetermined threshold value), the process proceeds to step S7.

  In step S7, a local minimum point Pan (in FIG. 1, Pa1 when n = 1 in FIG. 1) immediately after time from the n-th position Pn is detected by calculation. However, when the minimum point where the signal intensity changes from decreasing to increasing is not detected and the position of the measurement end time is detected, the position of the measurement end time is set to Pan.

  In step S8, the local minimum point Pbn from the decrease in the signal intensity immediately before the nth position Pn is detected by calculation. However, when the minimum point where the signal intensity changes from decreasing to increasing is not detected and the position of the measurement start time is detected, the position of the measurement start time is Pbn (in FIG. 1, Pb1 when n = 1). .

  In step S9, the received waveform in the range Rn (the range indicated by R1 when n = 1 in FIG. 1) between the minimum point Pan and the minimum point Pbn is changed to the nth waveform Wn (n in FIG. 1). When = 1, it is stored in the storage means as W1). Here, the nth waveform Wn should be regarded as a waveform based on the ultrasonic wave reflected from one object. The predetermined threshold value in step S6 is set to a value that does not cause the disturbance waveform to be stored in the storage means in step S9.

  In step S10, the nth waveform Wn is corrected so that the maximum signal intensity An (the signal intensity at the nth position Pn) of the nth waveform Wn is “1”, and an nth corrected waveform Wrn is generated. This is stored in the storage means (in FIG. 1, when n = 1, the waveform generated by correcting the maximum signal intensity A1 and the first waveform W1 is the first correction waveform Wr1 indicated by a broken line). Here, correcting the n-th waveform Wn so that the maximum signal intensity An of the n-th waveform Wn is “1” means that all signal intensities of the n-th waveform Wn are 1 / An times. Means.

  In step S11, n is set to n + 1 (the value of n is increased by 1). Then, the process returns to step S4. If n is 2 or more, the nth waveform Wn is stored in the storage means in step S9. Therefore, it is determined whether or not waveform information other than the received waveform stored in step S2 is stored in the storage unit in step S4 (YES (waveform information other than the received waveform stored in step S2 is stored in the storage unit)). The process proceeds to step S12.

  In step S12, the waveforms (first to (n-1) waveforms W1 to W (n-1)) stored in the storage unit in step S9 are removed from the reception waveform stored in the storage unit in step S1. Then, the process proceeds to step S5.

  However, if n is 2 or more, the received waveform stored in the storage means that is the target for calculating and detecting the nth position Pn in step S5 is processed in step S12. It is not a stored received waveform. That is, it is a part other than the waveforms (first to (n-1) waveforms W1 to W (n-1)) stored in the storage means in step S9 from the received waveform stored in step S2. In FIG. 1, when n = 2, it is a portion other than the first waveform W1 in the range of R1 in the entire received waveform.

  If the signal intensity at the calculated and detected nth position Pn (in FIG. 1, P2 when n = 2) is equal to or greater than a predetermined threshold, the determination in step S6 is YES, and steps S7 to S10 are performed again. Perform the following process. In FIG. 1, when n = 2, the second position P2, the minimum point Pa2, and the minimum point Pb2 are detected. Then, after storing the second waveform W2 in the range indicated by R2 (the range between the minimum point Pa2 and the minimum point Pb2) in the storage unit, the maximum signal intensity A2 (signal intensity at the second position P2) of the second waveform W2 is obtained. The second waveform W2 is corrected to be “1” to generate a second corrected waveform Wr2, which is stored in the storage means. That is, the processes in steps S4, S12, and S5 to S11 are repeated until the signal intensity at the nth position Pn is not greater than or equal to a predetermined threshold value in step S6, that is, until it is less than the predetermined threshold value.

  In step S6, if the signal intensity at the nth position Pn becomes less than a predetermined threshold value, the process proceeds to step S13.

  In step 13, N is set to n-1. Then, the process proceeds to step S14. In step S14, the spatial shape of the object is calculated and imaged based on the first to N correction waveforms Wr1 to WrN corrected and generated in step S10 for each receiving element and stored in the storage means. Delay multiplication is used for the calculation for obtaining the orientation of the object based on the correction waveform. Delay multiplication refers to performing multiplication instead of addition on a delay waveform in the description of delay addition described in paragraphs 0002 to 0007 of Patent Document 1. However, in the description in Patent Document 1, delay addition is performed using a circuit, but in this embodiment, delay multiplication is performed programmatically. The method for calculating the distance to the object based on the signal after the delay multiplication is the same as the method for calculating the distance to the object based on the signal after the delay addition (see Patent Document 1). An existing technique (for example, the imaging method described in Japanese Patent Laid-Open No. 2005-49303) is used as a method for imaging the spatial shape of the target object based on the obtained spatial shape information of the target object. . After imaging, the process ends.

  The maximum value of the correction waveform is “1”, which is the same as the maximum value of the correction waveform of the object having a strong received signal. Therefore, when delay multiplication is performed using the correction waveform, even a weak received signal object can be obtained with a signal having the same strength as the strong received signal object after delay multiplication. Therefore, an image of the spatial shape of the object can be obtained based on this signal.

  FIG. 3 schematically shows an example of the ultrasonic array sensor 1. An ultrasonic array sensor 1 shown in FIG. 3 includes a substrate 2, an ultrasonic transmission element 3, and eight ultrasonic reception elements 4. As the substrate 2, the ultrasonic transmission element 3, and the ultrasonic reception element 4, existing ones may be used.

  FIG. 4 schematically shows the configuration of the ultrasonic imaging apparatus. The ultrasonic imaging apparatus includes an ultrasonic array sensor 1, AD conversion means 5, calculation means 6, storage means 7, control means 8, correction means 9, imaging means 10, and image display means 11. The ultrasonic array sensor 1 is as described above. The AD conversion means 5 converts the received signal received by the ultrasonic array sensor 1 into digital data. The calculating means 6 detects the nth position Pn, the minimum point Pan, and the minimum point Pbn from the received waveform. The storage means 7 stores and holds the received waveform converted into digital data by the AD conversion means 5. The storage means 7 stores and holds the nth waveform Wn and the nth correction waveform Wrn. The control means 8 resets (initializes) the contents of the storage means in step S1 of FIG. The control unit 8 stores the nth waveform Wn in the storage unit 7. The control unit 8 stores the nth correction waveform Wrn in the storage unit 7. The control means 8 performs the determination in steps S4 and S6 in FIG. In step 12 of FIG. 2, the control means 8 removes the waveform stored in step S9 of FIG. 2 from the received waveform stored in step S1 of FIG. The control means 8 controls the progress of the steps in FIG. The correction unit 9 corrects the first to N waveforms W1 to WN stored and held in the storage unit 7 to obtain first to N correction waveforms Wr1 to WrN. The imaging means 10 calculates the spatial shape of the object based on the first to N correction waveforms Wr1 to WrN for each ultrasonic receiving element 4. The image display means 11 displays the spatial shape of the object calculated by the imaging means 10.

  FIG. 5 schematically shows the state of the experiment using the ultrasonic array sensor 1 shown in FIG. However, devices other than the ultrasonic array sensor 1 are omitted. Balloons 1 to 3 were fixedly arranged in front of the ultrasonic array sensor 1. The coordinate system is an XYZ coordinate system and the directions are as shown in FIG. Balloon coordinates are (0, 0, 100) for balloon 1, (−60, −25, 100) for balloon 2, and (60, 0, 130) for balloon 3 based on the center of the balloon (unit: cm, the origin is the center of the ultrasonic array sensor 1). The diameter of the balloon is 30 cm.

  FIG. 6 shows a received waveform of a signal received by the ultrasonic receiving element 4 and a corrected waveform generated by correcting the received waveform by the ultrasonic imaging method according to the present invention. The eight graphs in FIG. 6 show the waveforms received by each of the eight ultrasonic receiving elements 4 installed on the ultrasonic array sensor 1 for one transmission of the ultrasonic wave and the correction waveforms thereof. Show. In each graph, the thick solid line waveform is the original received waveform, and the thin solid line waveform is the correction waveform. However, for comparison, the signal intensity of the entire original received waveform is adjusted and displayed so that the correction waveform corresponding to the balloon 1 and the original received waveform are the same.

  First, for comparison, FIG. 7 shows a signal intensity obtained by delay multiplication based on the original received waveform in FIG. 6 expressed in shading on the XY coordinate plane. In the original received waveform of FIG. 6, the signal intensity of the balloon 1 is high because the center of the ultrasonic array sensor 1, the X coordinate, and the Y coordinate are the same. On the other hand, the signal intensity of the balloons 2 and 3 is smaller than the signal intensity of the balloon 1. When the delay multiplication is performed, the difference in signal strength becomes large. Therefore, after the delay multiplication, the signal strength of the balloon 2 and the balloon 3 becomes very small as compared with the signal strength of the balloon 1. Therefore, only the signal after delay multiplication of the balloon 1 is displayed in FIG.

  On the other hand, FIG. 8 shows the signal intensity obtained by delay multiplication based on the correction waveform of FIG. 6 expressed in shading on the XY coordinate plane. With respect to the correction waveform shown in FIG. 6, the maximum value of the signal intensity of the correction waveforms of the balloons 1 to 3 is “1”. For this reason, even after delay multiplication, the signal strengths of the balloons 2 and 3 are approximately the same as the signal strength of the balloon 1. Therefore, in FIG. 8, not only the balloon 1 but also the signals after delay multiplication of the balloons 2 and 3 are displayed.

  As described above, even if the intensity of the signal obtained by the ultrasonic receiving element is low, such as the balloon 2 or the balloon 3, the maximum value of the signal intensity of the received waveform of the signal obtained by the ultrasonic receiving element. Is corrected to be “1”, which is the same as that of the balloon 1, and a signal strength equivalent to that of the balloon 1 is obtained after delay multiplication. Therefore, it is possible to image the spatial shape based on the signal after the delay multiplication.

  Further, for comparison, FIG. 9 shows a received waveform of a signal received by the ultrasonic receiving element 4 and a corrected waveform generated by correcting the received waveform using a known waveform recognition method using a threshold value. The eight graphs in FIG. 9 show the waveform received by each of the eight ultrasonic receiving elements 4 installed on the ultrasonic array sensor 1 for one transmission of the ultrasonic wave and its correction waveform. Show. In each graph, the thick solid line waveform is the original received waveform, and the thin solid line waveform is the correction waveform. However, for comparison, the signal intensity of the entire original received waveform is adjusted and displayed so that the correction waveform corresponding to the balloon 1 and the original received waveform are the same.

  Here, the known waveform recognition method using a threshold value is a method in which the following steps (1) to (4) are performed. (1) The point where the signal strength is maximum in the received waveform is calculated. (2) A point that is equal to or less than a set threshold value immediately before and immediately after the point calculated in step (1) is detected. (3) The waveform between the two points detected in step (2) is stored as a waveform from one object. (4) Steps (1) to (3) are repeated except for the waveform stored in step (3), and the process ends when the signal intensity at the point calculated in step (1) is less than or equal to the set value. .

  The correction was performed so that the maximum value of the signal intensity of each waveform stored in step (3) was “1” (correction similar to the embodiment according to the present invention).

  However, in FIG. 9, there is a correction waveform having a maximum signal intensity of less than “1” (indicated by (a) in FIG. 9). Further, in FIG. 9, there is a place where a correction waveform is generated where there is no reception waveform from an object in the original reception waveform (indicated by (b) in FIG. 9).

  Further, FIG. 10 shows the signal intensity obtained by delay multiplication based on the correction waveform in FIG. 9 expressed in shading on the XY coordinate plane. In FIG. 10, the signal after delay multiplication of the balloon 2 is not displayed. This is because the correction waveform of FIG. 9 has a maximum signal intensity of less than “1” in the correction waveform of the balloon 2 (see FIG. 9A).

  As described above, the correction using the known waveform recognition method based on the threshold value cannot obtain the same accuracy as the correction using the ultrasonic imaging method according to the present invention.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, in the above-described embodiments, delay multiplication is performed for calculation for imaging. Although used, it is also possible to use delay addition for the calculation for imaging. In this case, it is possible to correct the waveform after delay addition instead of before delay addition.

  Further, in the above embodiment, the first to Nth waveforms W1 to WN are detected and stored in the storage means in order from the largest to the smallest in the original received waveform. On the contrary, it may be detected in the order from the smallest to the largest and stored in the storage means.

  In the above embodiment, the nth waveform Wn is corrected so that the maximum signal intensity An is “1”. However, the entire received waveform is adjusted so that the maximum signal intensity A1 of the first waveform W1 is “1”. May be corrected (amplified) so that the maximum signal strengths A2 to AN are “1” for the other second to Nth waveforms W2 to WN.

It is the figure which showed typically an example of the waveform of the signal obtained when the ultrasonic wave reflected on the target object was received by the ultrasonic wave receiving element. It is the figure which showed the procedure of the ultrasonic imaging method which concerns on embodiment of this invention with the flowchart. It is a figure which shows typically an example of an ultrasonic array sensor. It is a figure which shows typically the structure of an ultrasonic imaging device. It is a figure which shows typically the mode of the experiment using an ultrasonic array sensor. It is a figure which shows a correction | amendment waveform and the original received waveform. It is the figure which expressed the signal strength obtained by delay multiplication based on the original received waveform of FIG. 6 on the XY coordinate plane with shading. It is the figure which represented the signal strength obtained by carrying out delay multiplication based on the correction waveform of FIG. 6 which concerns on an Example on the XY coordinate plane with the shading. It is a figure which shows the correction | amendment waveform and the original receiving waveform by a well-known method. FIG. 10 is a diagram showing signal intensity obtained by delay multiplication based on the correction waveform of FIG. 9 in light and shade on an XY coordinate plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic array sensor 2 Board | substrate 3 Ultrasonic transmission element 4 Ultrasonic receiving element 5 AD conversion means 6 Calculation means 7 Storage means 8 Control means 9 Correction means 10 Imaging means 11 Image display means

Claims (7)

The ultrasonic wave emitted from the ultrasonic transmitting element is reflected by the object and reflected, and the reflected wave is received by an ultrasonic array sensor in which a plurality of ultrasonic receiving elements are arranged, and the signal intensity obtained by each receiving element In the ultrasonic imaging method of imaging the spatial shape of the object based on the relationship between the transmission and reception times,
From the received waveform of the signal strength obtained by each receiving element,
(A) calculating the n-th position where the signal intensity is maximum for each receiving element;
(B) calculating a pair of local minimum points at which the signal intensity immediately before and after the nth position changes from decreasing to increasing;
(C) storing the received waveform between the pair of minimum points in the storage means as the nth waveform;
(D) Steps (a) to (c) are repeated (N-1) times for the received waveform not stored in step (c), and the storage means stores the first waveform to the Nth waveform. Memorizing process,
(E) The ultrasonic imaging method characterized in that the spatial shape of the object is imaged based on the first waveform to the Nth waveform for each receiving element stored in the storage means. Here, n is an integer, and is increased from 1 to N in order. 2. The ultrasonic imaging method according to claim 1, wherein the value of N is set corresponding to the number of received waveforms in the step (c) that are equal to or greater than a predetermined threshold relating to signal intensity. 3. The method according to claim 1, further comprising a step of correcting the maximum values from the first waveform to the Nth waveform of each receiving element to be equal to each other and storing them in the storage unit. Sonic imaging method. The ultrasonic imaging method according to claim 1 , wherein the number of repetitions of claim 1 is limited so that a disturbance waveform does not enter the received waveform stored in the storage unit. The ultrasonic wave emitted from the ultrasonic transmitting element is reflected by the object and reflected, and the reflected wave is received by an ultrasonic array sensor in which a plurality of ultrasonic receiving elements are arranged, and the signal intensity obtained by each receiving element In the ultrasonic imaging apparatus that images the spatial shape of the object based on the relationship between the transmission and reception times,
First calculation means for calculating the n-th position where the signal intensity is maximum for each receiving element from the received waveform of the signal intensity obtained by each receiving element;
Second computing means for computing a pair of local minimum points at which the signal strength immediately before and after the n-th position changes from decreasing to increasing;
Storage means for storing a received waveform between the pair of local minimum points as an nth waveform, and first control means for storing the nth waveform in the storage means;
The step of calculating the nth position where the signal intensity becomes the maximum value for each receiving element with respect to the received waveform not stored in the step of storing the received waveform between the pair of local minimum points as the nth waveform in the storage means. , A step of calculating a pair of local minimum points at which the signal intensity immediately before and after the nth position changes from decreasing to increasing, and a step of storing the received waveform between the pair of local minimum points in the storage means as the nth waveform (N -1) second control means for repeatedly storing the first waveform to the Nth waveform in the storage means;
An ultrasonic imaging apparatus comprising: imaging means for imaging a spatial shape of the object based on a first waveform to an Nth waveform for each receiving element stored in the storage means. Here, n is an integer, and is increased from 1 to N in order. Corresponding to the number of the received waveform of the received waveform between a predetermined threshold value or more pair of minimum points regarding signal strength as engineering to be stored in the storage means as the n waveform having a third control means for setting the value of the N The ultrasonic imaging apparatus according to claim 5. A correction unit that corrects the maximum values from the first waveform to the Nth waveform of each receiving element to be equal, and a fourth unit that stores the N waveform from the first waveform corrected by the correction unit in the storage unit. The ultrasonic imaging apparatus according to claim 5, further comprising a control unit.