SYSTEM FOR ULTRASONIC EXAMINATION

Abstract: A computerized system for the recording of flaw images by ultrasonic examination according to the pulse-echo method includes at least one ultrasonic probe which can be moved in steps over the surface of an object along a rectilinear scanning path. Digital signals containing information on the successive positions of the sound beam, on echo amplitudes, and on the lengths of sound paths to reflectors inside the object, are processed and used for the accumulated storage of circular patterns of echo amplitude data in a matrix memory associated with a sectional plane through the object. A video screen terminal controls the system and transforms the accumulated data into displays of sectional flaw images of greatly improved precision and sharpness of definition. A gradual transfer of filtered data from a number of parallel sectional planes to three further matrix memories associated with projection planes at right angles to each other permits presentation in three dimensions of equally improved projection flaw images.

Description: SYSTEM FOR ULTRASONIC EXAMINATION BACKGROUND OF THE INVENTION !• Field of the invention This invention relates to the production and re¬ cording of inhomogeneities in otherwise homogeneous ob- jects having a plane or locally substantially plane sur¬ face, by ultrasonic examination according to the pulse- echo method. The production and recording of correct and well-defined images of internal inhomogeneities is a mat¬ ter of the greatest importance for the correct location and sizing of internal flaws in materials and welded joints, and thus for the safety and fitness for purpose of important structures and installations. 2. Background of the Prior Art In the ultrasonic examination art, great efforts have been made to develop improved systems for the lo¬ cation and sizing of flaws in materials and welded joints, in particular systems producing easily readable images of internal flaws. In many systems this has been made possible through the use of digital computing means including electronic matrix memories for the storage of echo data which may then be analysed, displayed on video monitors as grey scale or colour images, and permanent¬ ly recorded by magnetic recording means or permanent prints. Examples of extensive descriptions of ultrasonic examination systems of this kind for producing sectio¬ nal views (B-scan displays) and plan views (C-scan dis¬ plays) are U.S. Flathery et al.Patent No. 3.673.860 and U.S. Beller Patent No. 3.857.052. Improved systems for the storage and display of complete projection images (P-scan displays) of flaws located in the interior of materials and welded joints have been described in U.S. Lund et al. Patents Nos. 3.939.697 and 4.226.122. How¬ ever, none of the prior art examination systems have been entirely satisfactory. The major and overriding problems in ultrasonic examination have not been associated with the ultrasonic equipment and techniques themselves, but with the com¬ plete and objective analysis and interpretation of the data, in particular the exact location and sizing of flaws. Small, but significant anomalies in the data are often overlooked, because the data is irregular and noi¬ sy, and the unavoidable beam spread of the ultrasonic sound beam leads to indistinct outlines of the flaw ima- ges. SUMMARY OF THE INVENTION The system according to the present invention has been evolved with the general object of overcoming the disadvantages of the prior art by providing sectional and projection views showing flaw images of hitherto un¬ known precision and sharpness of definition. According to the invention, there is provided an examination system comprising at least one ultrasonic probe which can be moved over the surface of the object in steps of predetermined lengths along a rectilinear scanning path containing the projection on the surface of the central axis of the sound beam; position signal producing means adapted to produce digital signals con¬ taining information on the positions on said surface of the successive points of incidence of the sound beam; ultrasonic equipment adapted to make said probe emit, on completion of each step of movement, at least one short pulse of ultrasonic energy into the object, and adapted, on receipt of an echo pulse, to produce digital echo signals containing information on the amplitude of said pulse, and on the length of the sound path from said point of incidence to the reflecting point causing the • > echo pulse; digital computing means, including a first electronic matrix memory for data produced by the exami- 5 nation, said first matrix memory having storage addres¬ ses arranged in lines and columns associated with a si¬ milar, corresponding network of lines and columns of rectangular coordinates in the sectional plane through the object defined by the scanning path, of the ultra- 10 sonic probe and the central axis of the sound beam, each storage address being adapted to store data representing said echo amplitudes, and adapted, on receipt of a new data item, to add said new data item to the sum of data items previously stored at said storage address; first 15 control means for storing in said first matrix memory, upon receipt of said position signal and said echo pulse signals, data representing said echo amplitude at all storage addresses located on a circle, having as its centre the storage address associated with said point of 20 incidence, and having as its radius the distance in said first matrix memory corresponding to said length of the sound path through the object; a video screen terminal for controlling the scanning movement of said ultraso¬ nic probe, for controlling the functioning of said ul- 25 trasonic equipment, said digital computing means, and said first control means, and for displaying sectional images derived from data stored in said first matrix memory; recording means for producing permanent, elec¬ tronically readable records of data stored in said first 30 matrix memory, and of sectional images displayed on said j screen terminal; and printing means for producing perma¬ nent prints of images displayed on said screen terminal. Through this new and, in principle, quite simple storage system, echo amplitudes from significant flaws 35 are drastically amplified due to the frequently repea- ted and accumulated storage of amplitude data at the same storage addresses, while the echo amplitudes of non-re¬ current random noise signals remain substantially unamp- lified. At the same time, the effect of the beam spread of the sound beam is practically eliminated, because flaw echo amplitudes are no longer stored only at storage ad¬ dresses associated with the central axis of the sound beam, but simultaneously at all storage addresses asso¬ ciated with the true path lengths, i.e. the true transit times measured for the individual echo pulses. When the accumulated sums of echo amplitude data items stored are displayed on the video screen in grey scale or colour presentations, it becomes possible to produce and record sectional flaw images (B-scan displays) of hitherto un- known precision and sharpness of definition. According to the invention, an extended examina¬ tion system may further be provided wherein said ultra¬ sonic probe can be moved over the surface of the object along a number of successive, parallel rectilinear scan- ning paths at predetermined intervals; said digital com¬ puting means further includes a second electronic matrix memory for data produced by the examination, said second matrix memory having storage addresses arranged in lines and columns associated with a similar, corresponding net- work of lines and columns of rectangular coordinates in a projection plane parallel to the surface of the object, each storage address being adapted to store sums of data items representing said echo amplitudes; said digital computing means further includes second control means adapted, on completion of each movement of said ultra¬ sonic probe along the length of a scanning path, to read from the storage addresses arranged in each column of said first matrix memory the highest sum of data items stored in said column, to store said highest sums of da- ta at the corresponding storage addresses in said se- cond matrix memory in the column associated with the li¬ ne of intersection between said sectional plane and said projection plane, and to reset all storage addresses in said first matrix memory at zero value; said video screen terminal is further adapted to control the functioning of said second control means, and to display projection images derived from data stored in said second matrix memory; and said recording means is further adapted to produce permanent, electronically readable records of data stored in said second matrix memory. Through this second storage, column by column, of the selected highest sums of echo amplitude data items obtained in a number of parallel sectional scannings, it becomes possible to .produce and record projection flaw images (P-scan plan view displays) of hitherto unknown precision and sharpness of definition. According to the invention, extended examination systems may further be provided, comprising the possibi¬ lities of producing similar projection flaw images on projection planes at right angles to the surface of the object and at right angles and/or parallel to the scan¬ ning paths for the ultrasonic probe. In this manner it becomes possible to produce and record improved further projection flaw images (P-scan side and end view dis- plays) , and thus to obtain a precise location and sizing of all internal inhomogeneities in three dimensions. Other objects and advantages of the invention will be readily apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic presentation, partly as an isometric view, and partly as a block diagram, of an inspection system according to the present invention; and Figure 2 is a schematic presentation of the pro- duction and storage of a sectional image (B-scan display) by means of the system of Figure 1. DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Figure 1 shows schematically an inspection system for producing and recording images of inhomogeneities 1 in an otherwise homogeneous object 2 having a plane sur¬ face 3. The system comprises an ultrasonic probe 4 which can be moved, manually or automatically, in steps of pre¬ determined lengths along a rectilinear scanning path 5 containing the projection on the surface 3 of the cen¬ tral axis 6 of the sound beam emitted by the probe 4. Position signal producing means 7,8 including position transducers and analogue-to-digital converting means, are adapted to produce and transmit digital signals con- taining information on the positions on the surface 3 of the successive points of incidence 9 of the sound beam. Ultrasonic equipment 10 is adapted to make the probe 4 emit, on completion of each step of movement, one or mo¬ re short pulses of ultrasonic energy into the object 2, and, on receipt of an echo pulse, to produce and trans¬ mit digital echo signals containing information on the amplitude (a) of the echo pulse, and on the length of the sound path 11 from the point of incidence 9 to the reflecting inhomogeneity 1 causing the echo pulse. Position and echo pulse signals are carried to digital computing and control means 12 including one or more electronic matrix memories 13, 19, 22, 25 for data produced by the examination. A video screen terminal 16 controls the scanning movement of the ultrasonic probe 4, controls the functioning of the ultrasonic equipment 10 and the digital computing and control means 12, and dis¬ plays images derived from data stored in the matrix me¬ mories 13, 19, 22, 25. Recording means 17 is provided for producing permanent, electronically readable records of data stored in the matrix memories 13, 19, 22, 25, and of images displayed on the screen terminal 16. Prin¬ ting means 18 is provided for producing permanent prints of images displayed on the screen terminal 16. Figure 2 further illustrates schematically the operation of the examination system when producing an image (B-scan display) of a sectional plane 14 through the object 2. The first matrix memory 13 has storage ad¬ dresses (y' , z 1 ) arranged in lines z' and colums y 1 which are associated with a similar, corresponding net- work of lines z and columns y of rectangular coordinates (y, z) in the sectional plane 14 through the object de¬ fined by the scanning path 5 of the ultrasonic probe 4 and the central axis 6 of the sound beam. Each storage address (y', z 1 ) is adapted to store data representing echo amplitudes (a) , and adapted, on receipt of a new data item, to add the new data item (a) to the sum of data items (∑a) previously stored at the same storage address. First control means included in the digital com- puting means 12 is adapted to arrange for the simulta¬ neous storage in the first matrix memory 13 , upon re¬ ceipt of position and echo pulse signals, of data repre¬ senting the echo amplitude (a) at all storage addresses (y 1 , z 1 ) located on a circle 15, having as its centre the storage address (y , Zg) associated with the correspon¬ ding point of incidence 9 of the sound beam on the sur¬ face 3 of the object 2 , and having as its radius the dis¬ tance 11' in the matrix memory 13 which corresponds to the length of the sound path 11 from the point of inci- dence 9 to the reflecting inhomogeneity 1 inside the ob- ject. The operation of the illustrated examination sy¬ stem is as follows. The ultrasonic probe 4 is mounted on the surface 3 of the object 2 , placing the point of in- cidenσe 9 at the beginning of the scanning path 5, and O co to to μ i H LΠ o tn o LΠ o LΠ C sectional image may be limited to include only stored sums of data items (∑a) which are higher than an optional display limit 28. The data stored in the first matrix memory 13 and the sectional images displayed may further be permanent¬ ly recorded by the recording means 17 as electronically readable records that may be reinserted in the matrix memory 13 and redisplayed on the video screen for further analyses and comparisons at any later moment. The images displayed may further be copied in the form of permanent prints by the printing means 18. It will be readily apparent from the above des¬ cription that the examination system invented is able to produce flaw images of greatly improved precision and sharpness of definition. The accumulation of echo data items in the immediate vicinity of the intersections of the circles 15, 15a, 15b, 15c corresponding to the true position of the inhomogeneity 1 leads to a corresponding¬ ly increased contrast and sharpness of the flaw image, while the echo amplitudes of non-recurrent random noise signals remain substantially unamplified. The image qua¬ lity obtained in this manner may be further improved by using smaller steps in the scanning movement of the pro¬ be 4, by using a finer network of storage addresses in the matrix memory 13, and by using a correspondingly greater number of pixels in the screen image of the ter¬ minal 16. It will further be obvious to a person skilled in the art of ultrasonic examination with electronic data processing that it will be possible to construct a great number of suitable variants of the illustrated embodi¬ ment without deviating from the basic principles of the present invention. The ultrasonic probe 4 may thus be an angle probe or a normal probe, and may suitably be replaced by a nu - ber of individual probes or by an array of ultrasonic transducers to be moved stepwise along the scanning path 5. The echo signals may, for greater accuracy, be etablished as averaged values from a number of ultraso¬ nic pulses emitted in each scanning position of the pro¬ be 4, and the digital data items to be stored in the ma¬ trix memory 13 may represent any suitable function of the echo amplitudes. One obvious choice would be to sto- re and accumulate data items corresponding to the loga¬ rithmic values of the peak echo amplitudes, but other functions might be even more expedient considering the limitations in storage capacity at the individual sto¬ rage addresses in the matrix memory 13. The various components needed in the construction " of an examination system as invented may by a person skilled in the art be -.chosen among a great number of currently available components for ultrasonic examina¬ tions, and for the production, processing, storage, dis- play, and recording of digital data signals. It will also be obvious that the system invented will be equally suitable for local examinations of ob¬ jects having slightly curved surfaces, and for the ex¬ amination of cylindrical objects such as tubes and pipes or pressure vessels, where the scanning paths may be cho¬ sen to be parallel to the axis of the cylindrical object. According to the invention, the examination system may be extended to be able to produce equally improved projection flaw images on " one or more projection planes 20, 23, 26 at right angles to each other as indicated schematically in Figure 1. In this case the ultrasonic probe 4 is adapted to be moved over * the surface 3 of the object 2 along a number of successive, parallel recti¬ linear scanning paths 5, 5a, 5b, 5c at predetermined in- tervals, and part of the sectional image data obtained in this manner is then used to constitute the data need¬ ed for producing projection images. The digital computing means 12 then further in¬ cludes a second electronic matrix memory 19 for. data pro- duced by the examination. The second memory 19 has sto¬ rage addresses (x* , y 1 ) arranged in lines y 1 and columns x 1 associated with a similar, corresponding network of lines y and columns x of rectangular coordinates (x, y) in a projection plane 20 parallel to the surface 3 of the object 2, and the storage addresses (x 1 , y') are adapted to store sums of data items (∑a) representing the echo amplitudes. Second control means included in the digital com¬ puting means 12 is adapted, on completion of each scan- ning movement of the probe 4 along the length of a scan¬ ning path 5, 5a, 5b, 5c, to read from the storage addres¬ ses (y 1 , z') arranged in each column y 1 of the first ma¬ trix memory 13 the highest sum of data items ( (∑ a ) mav ) stored in said column y 1 , and adapted to store these highest sums of data items ((∑a)max) at the corresponding storage addresses (x 1 , y 1 ) in the second matrix memory 19 in the column x' associated with the line of inter¬ section 21, 21a, 21b, 21c between the sectional plane 14, 14a, 14b, 14c and the projection plane 20. This data transfer has been indicated schematical¬ ly in Figure 2. The highest sums of data items ((∑a)max.) read from each column y' in the first memory 13 have been illustrated by the curve 29. The values illustrated by the curve 29 are then stored in the second matrix me- mory 19 along the corresponding column x 1 associated with the line of intersection' 21 between the sectional plane 14 and the projection plane 20. Upon completion of this transfer, all storage addresses in the first memory 13 can, automatically or by order from the terminal 16, be reset at zero value in readiness for the storage of new data items resulting from the scanning of the follo¬ wing sectional plane 14a along the scanning ^ .path 5a. In this manner the second matrix memory 19 is brought, column by column, to-contain the accumulated da- ta belonging to an image projected on to the projection plane 20. Upon completion of the entire scanning proce¬ dure, the accumulated data can be transfered into the display on the video screen of the terminal 16 of a com¬ plete projection image (P-scan plan view) of greatly im- proved precision and sharpness of definition. The data stored in the second matrix memory 19 and the projection images displayed may be permanently recorded by the re¬ cording means 17, and the images displayed may be copied in the form of permanent prints by the printing means 18. According to the invention, the examination system may be extended in a quite similar manner to be able to produce improved projection flaw images on a projection plane 23 at right angles to the surface 3 of the object 2, and at right angles to the scanning paths 5, 5a, 5b, 5c of the probe 4. In this case the digital computing means further includes a third electronic matrix memory 22 for data produced by the examination. This third memory 22 has storage addresses (x 1 , z') arranged in lines z 1 and co- lumns x 1 associated with a similar, corresponding net¬ work of lines z and columns x of rectangular coordinates in the projection plane 23, and the storage addresses (x 1 , z') are adapted to store sums of data items (∑a) re¬ presenting the echo amplitudes. Third control means included in the digital compu¬ ting means 12 is adapted, on completion of each scanning movement of the probe 4 along the length of a scanning path 5, 5a, 5b, 5c, to read from the storage addresses (y 1 , z') arranged in each line z 1 of the first matrix me- mory ■ * 13 the hig^hest sum of data items ( (∑a)max) stored in said line z 1 , and adapted to store these highest sums of data items ( (∑a) ) at the corresponding storage ad¬ dresses (x 1 , z') in the third matrix memory 22 in the column x 1 associated with the line of intersection 24, 1 5 24a, 24b, 24c between the sectional plane 14, 14a, 14b, 14c and the projection plane 23. This data transfer has been indicated schematical¬ ly in Figure 2. The highest sums of data items (( ∑a ) maχ ) read from each line z' in the first memory 13 have been 10 illustrated by the curve 30. The values illustrated by the curve 30 are then stored in the third matrix memory 22 along the corresponding column x 1 associated with the line of intersection 24 between the sectional plane 14 and the projection plane 23. Upon completion of the two 15 data transfers from memory 13 to memories 19 and 22, all storage addresses in the first memory 13 can, automati¬ cally or by order from the terminal 16, be reset at zero value in readiness for the storage of new data items re¬ sulting from the scanning of the following sectional 20 plane 14a along the scanning path 5a. In this manner the third matrix memory 22 is brought, column by column, to contain the accumulated data belonging to an image projected on to the projection plane 23. Upon completion of the entire scanning proce- 25 dure, the accumulated data can be transformed into the display on the video screen of the terminal 16 of a com¬ plete projection image (P-scan side view) of greatly im¬ proved precision and sharpness of definition. The data stored in the third matrix memory 22 and the projection 30 images displayed may be permanently recorded by the re- * ' cording means 17, and the images displayed may be co¬ pied in the form of permanent prints by the printing means 18. According to the invention the examination system 35 may finally be extended to be able to produce improved flaw images on a projection plane 26 at right angles to the surface 3 of the object 2, and parallel to the scan¬ ning paths 5, 5a, 5b, 5c of the probe 4. In this case the digital computing means-12 -fur- ther includes a fourth electronic matrix memory 25 for data produced by the examination. This fourth matrix me¬ mory 25 has storage addresses (y 1 , z') arranged in lines z' and columns y' associated with a similar, correspon¬ ding network of lines z and columns y of rectangular co- ordinates (y, z) in the projection plane 26, and the storage addresses (y 1 , z') are adapted to store sums of data items (∑a) representing the echo amplitudes. Fourth control means included in the digital com¬ puting means 12 is adapted, on completion of each scan- ning movement of the probe 4 along the length of a scan¬ ning path 5, 5a, 5b, 5c, to read from each storage ad¬ dress (y 1 , z 1 ) in the first matrix memory 13 the sum of data items (∑a) stored at said address (y 1 , z 1 ) / and to store said sum of data items (∑a) at the corresponding address (y 1 , z 1 ) in the fourth matrix memory 25, but on¬ ly if a higher sum of data items has not already been stored at the storage address in question. Upon comple¬ tion of the three data transfers from memory 13 to memo¬ ries 19, 22 and 25, all storage addresses in the first memory 13 can, automatically or by order from the termi¬ nal 16, be reset at zero value in readiness for the sto¬ rage of new data items resulting from the scanning of the following sectional plane 14a along the scanning path 5a. In this manner the fourth matrix memory 25 is brought, transfer by transfer, to contain the accumula- ted data belonging to an image projected on to the pro¬ jection plane 26. Upon completion of the entire scanning procedure, the accumulated data can be transformed into the display on the video screen of the terminal 16 of a complete projection image (P-scan end view) of greatly improved precision and sharpness of definition. The data stored in the fourth matrix memory 25 and the projection images displayed may be permanently recorded by the re- cording means 17, and the image displayed may be copied in the form of permanent prints by the printing means 18. The three projection images may, like the sec¬ tional images, be subjected to digital image processing and image analysis, such as image filtering, contrast enhancement, grey scale or colour presentations, and the projection images may be limited to include only sto¬ red sums of data items (∑a) which are higher than an op¬ tional display level 28. The image quality obtained may be further improved by using smaller intervals between the scanning paths 5, 5a, 5b, 5c of the probe 4, by using a finer network of storage addresses in the matrix memo¬ ries 13, 19, 22, 25, and by using a correspondingly grea¬ ter number of pixels in the screen image of the terminal 16. During an automatic examination of an object, the operator may follow the gradual build-up of sectional and/or projection images on the screen of the terminal 16, and may interrupt the scanning procedure before the automatic erasing of a sectional image of particular in- terest. In this manner he is able to make permanent re¬ cords and prints of particularly interesting sectional images, before continuing the automatic examination and re-use of the first matrix memory 13. This feature em¬ phasises another aspect of the superiority of the inven- ted system in relation to prior art. In prior art it has been necessary, in order to obtain comparably high-quality sectional and projection images, to store position and echo pulse signals from every small element of the entire volume of the object examined, and to subject this vast amount of data to com- prehensive and complicated mathematical analysis and processing. This again requires the application of very considerable computing power and magnetic storage and re¬ cording capacity, and the equipment needed consequently becomes expensive, bulky, heavy, and complicated in prac¬ tical use. In comparison, the invented system requires only small computing power and storage and recording ca¬ pacity, and can easily be combined into one lightweight, hand-portable unit which is quite simple to operate in practical use. It will be understood that several modifications and variations of the described systems may be effected without departing from the spirit and scope of the novel concepts of the present invention.

Claims: PATENT CLAIMS 1. A system for producing and recording images of inhomogeneities in otherwise homogeneous objects having a plane or locally substantially plane surface, by ul- trasonic examination according to the pulse-echo method, comprising: at least one ultrasonic probe which can be moved over the surface of the object in steps of predetermined lengths along a rectilinear scanning path containing the projection on the surface of the central axis of the sound beam, position signal producing means adapted to pro¬ duce digital signals containing information on the po¬ sitions on said surface of the successive points of in- cidence of the sound beam, ultrasonic equipment adapted to make said probe emit, on completion of each step of movement, at least one short pulse of ultrasonic energy into the object, and adapted, on receipt of an echo pulse, to produce di- gital echo signals containing information on the ampli¬ tude of said echo pulse, and on the length of the sound path from said point of incidence to the reflecting point causing the echo pulse, digital computing means, including a first electro- nic matrix memory for data produced by the examination, said first matrix memory having storage addresses arran¬ ged in lines and columns associated with a similar, cor¬ responding network of lines and columns of rectangular coordinates in the sectional plane through the object de- fined by the scanning path of the ultrasonic probe and the central axis of the sound beam, each storage address being adapted to store data representing said echo am¬ plitudes, and adapted, on receipt of a new data item, to add said new data item to the sum of data items previous- ly stored at said storage address, first control means for storing in said first matrix me¬ mory, upon receipt of said position signal and said echo pulse signals, data representing said echo amplitude at all storage addresses located on a circle, having as its centre the storage address associated with said point of incidence, and having as its radius the distance in said first matrix memory corresponding to said length of the sound path through the object, a video screen terminal for controlling the scan- ning movement of said ultrasonic probe, for controlling the functioning of said ultrasonic equipment, said di¬ gital computing means, and said first control means, and for displaying sectional images derived from data stored in said first matrix memory, recording means for producing permanent, electro¬ nically readable records of data stored in said first matrix memory, and of sectional images displayed on said screen terminal, and printing means for producing permanent prints of images displayed on said screen terminal. 2. The combination of claim 1 wherein: said ultrasonic probe can be moved over the sur¬ face of the object along a number of successive, paral¬ lel rectilinear scanning paths at predetermined inter- vals, said digital computing means further includes a second electronic matrix memory for data produced by the examination, said second matrix memory having sto¬ rage addresses arranged in lines and columns associated with a similar, corresponding network of lines and co¬ lumns of rectangular coordinates in a projection plane parallel to the surface of the object, each storage ad¬ dress being adapted to store sums of data items repre¬ senting said echo amplitudes, said digital computing means further includes se- LO O to t μ Lπ o Ul o Lπ o LΠ 01 tt 01 Pi H P Ω P 3 2 i φ P Φ ø 3 Ω d tr rt d Φ 3 O Pi Φ μ- H 01 Hi P μ- Φ P g μ- o Ω Pi Pi 3 Pi £ Φ rt Ω 3 3 3 01 ti •I φ ιt H P 01 i * XX It Pi Pi Φ μ- ft H Φ 3 01 01 P o Pi •d 3 P o 01 Pi rt φ (t Ω .3 P Ω Hi Φ Φ μ-" 01 tr 01 a P P P Hi Ω H 01 CO μ- H 01 01 Pi 01 Φ 01 Φ 01 μ i it 3 Pi Φ P • 3 g P P μ- rt P 01 P μ- μ- τ* tr 01 ft P Ω μ- P μ- μ- 01 tr μ- μ- 3 P rt g P H rt It Pi r3 01 3 Pi Pi •d φ . μ- Pi μ- Hi Φ p μ- P P H tr P Φ t- i 3 3 01 3 ft Pi t- i o i φ μ- 3 H 01 P Hi < ► d Φ P i 01 Q P μ- 3 μ- Pi rt Φ Φ *< d μ- 01 μ- P Hi 0 3 tt μ ιp Ω ^ Ω Ω 3 Pi P O P Pi It 01 H μ i Φ Φ Ω μ- P 01 P P •d Ω Φ μ- LJ. Hi P rt 01 φ rt P 3 rt Φ Φ H 3 ti rt P Pi Φ 01 P P P ii 3 oi 3 P & Ω μ* Pi Pu P μ- Ω μ- μ- H μ- i P 01 P μ* μ- P Φ μ- LJ. P 01 Hi rt 3 rt Φ Pi 01 P it 3 3 Ω 3 3 Φ 3 Ω μ- μ- rt Φ i Hi P P tt H Ω P Pi IT i P Ω μ- ti H P Φ 3 Hi H 3 Pi μ- o it rt tt 3 Φ 01 3 H 01 μ- μ- P μ- P £ X 3 μ- 3 P 3 H μ- Φ rt 01 3 H 3 Ω .3 .3 P P 3 φ μ- P a •d φ P 01 ft φ 3 d 3 rt μ- P X 3 P 3 μ- 1 Ω ft rt 01 tt rt •d Φ Φ it ti Ω 3 Hi rt P P rt P tr ti Pi Ω 3 μ- P μ- P 01 3 μ- Φ rt 3 μ- . • It μ- 3 φ P o Ω a Hi X φ 3 01 H H Φ P 3" P P tr C H ti XX μ- μ- 3 P P 3 μ- a Φ rt 01 Φ P H •<: Ω 3 * 01 P ιp μ* μ- X 3 Ω H rt 3 Φ 3 μ Φ Φ Pi 3 P tr Q Ω P μ- O P 01 Hi Φ P 3 H Hi K; 01 P 3 3 Φ P μ> X H μ« Ω •d P P μ- P Φ d 01 μ 1 Pi rt H cz P P o o H a 3 ti P H Pu Φ 3 s. H 3 XX 3 3 3 01 *< Pi £ P φ Ω μ- P tt Φ . • Φ ø φ φ ι •d Pi Pi to • P 3 ti Ω 01 H P Φ 01 •» 3 μ i μ- P Hi tr Φ Pi μ- 3 K: a i .3 P P rt φ 3 rt 0 53 μ H < Pi Hi H P rt H Pi tr rt ιp P H ur Φ φ 0 P Φ 01 φ a o *< i Φ μ- rt 01 P Ω Pi H o 01 H φ £ φ P Pi Ω H •d ϋ H Pi P It Φ μ- O μ- 01 it Φ μ- 3 rt φ Φ P Hi 3 tr N rt i 3 rt ur 01 φ o o ti μ- Ω .3 H It Φ Φ ø ιP P φ 01 3 o H Pi 3 P tt o H ti H P 01 3 ti Φ IP Hi P d μ- »• li Φ 3 P P μ- Φ 01 Φ tr 01 rt ιP Ω 3 Pi i P t- 1 Ω P rt μ- tr φ Φ Φ Ω 01 i Pi <! tt 01 P 01 XX P P Pi μ- it P 3 P P 01 μ- 01 H P tr H P Ω P d P P rt Φ .3 It P o P μ- Φ H Hi tr i tr i Hi P P it d o a Ω XX Pi 01 P Pi * Φ .3 3 Φ φ ti P μ- Φ tt 3 P 3 H 01 P H 01 01 Pi ^ P μ- P tr IP P Φ et P P rt *-. ιp rt P μ- 01 Φ 01 < 01 Ur P ft 1 P ft Φ •d φ i ιP i Ω φ 1 Φ P 1 P μ- Pi 1 ur P 1 P 1 μ- 3 1 3 1 ses in said third matrix memory in the column associated with the line of intersection between said sectional pla¬ ne and said projection plane, and to reset all storage addresses in said first matrix memory at zero value, said video screen terminal is further adapted to control the functioning of said third control means, and to display projection images derived from data stored in said third matrix memory, and said recording means is further adapted to produce permanent, electronically readable records af data sto¬ red in said third matrix memory. 4. The combination of claim 3 wherein: said digital computing means further includes a fourth electronic matrix memory for data produced by . the examination, said fourth matrix memory having storage addresses arranged in lines and columns associated with a similar,corresponding network of lines and columns of rectangular coordinates in a projection plane at right angles to the surface of the object and parallel to said scanning paths, each storage address being adapted to store sums of data items representing said echo ampli¬ tudes, said digital computing.means further includes fourth control means adapted, on completion of each mo- vement of said ultrasonic probe along the length of a scanning path, to read from each storage address in said first matrix memory the sum of data items stored at said storage address, to store said sum of data items at the corresponding address in said fourth matrix memory, but only if a higher sum of data items has not already been stored at the storage address in question, and to reset all storage addresses in said first matrix memory at zero value, said video screen terminal is further adapted to control the functioning of said fourth control means. and to display projection images derived from data sto¬ red in said fourth matrix memory, and said recording means is further adapted to pro¬ duce permanent, electronically readable records of data stored in said fourth matrix memory.

Inventors: KRISTENSEN WILLY DAMGAARD, LUND SVEND AAGE, KRISTENSEN, WILLY, DAMGAARD, LUND, SVEND, AAGE
Applicants: AKAD TEKN VIDENSKABER, AKADEMIET FOR DE TEKNISKE VIDENSKABER, SVEJSECENTR
Application year: 1986
Main classification: G01N29
IPC codes: G01N29, G01S15