JP2017505425A - System and corresponding method for determining at least part of the shape of a three-dimensional object - Google Patents

Abstract

The present invention relates to a system (1) and method for determining at least part of the shape of a three-dimensional object (2). The system has a detector in the pressure zone detection member (6) arranged so that an object can be applied to it, and means (3) for calculating the distribution of the measured pressure in order to determine the shape from the measured pressure An element (5) for connecting the members; the computing means (3); and means (9) for applying the object to the detector member at a constant pressure. The detector member (6) comprises a piece (14) comprising a sheet (14) of flexible plastic material rigidly connected to the grid (19) of the pressure sensor (17), said grid comprising an intermediate layer. Including. The intermediate layer includes a microcrystalline silicon semiconductor wafer having a resistivity that varies with pressure and having a thickness of 50 nanometers or less.

Description

The present invention relates to a system for determining at least part of the shape of a three-dimensional object by means of an external sensor.

  The invention also relates to a method for implementing such a system.

BACKGROUND The present invention is not particularly limited, but is particularly applicable to the field of modeling a target object having a complex shape, making it possible to determine the shape in particular in the micrometer size, for example dentistry It is applicable in the field to modeling interface surfaces that exist between movable parts having complementary shapes.

  The term “complex shape” is understood herein to mean the shape of an object having an outer surface that includes a number of irregularities or singularities (inflection points, depressions, protrusions, etc.).

  “Determine at least part of the shape of the three-dimensional object” as used herein corresponds to or substantially corresponds to the contour of the sensor interface and the contour of the object to be determined above the determined height. It is understood that this means obtaining a set of digital data by measurement.

  Therefore, the collected data can be processed by calculation means, such as a computer.

  Devices that make impressions are known, for example by modeling. These devices cannot obtain a digital model, particularly in relation to the strain resistance of the surface data relating to the object.

  Optical shape recognition devices are also known, but these devices are not very accurate at small sizes. These devices are also very sensitive to usage conditions, such as brightness, contrast between the object and the background, can only be modeled with limited values, and are complementary to each other. The shape cannot be evaluated.

  Electronic recognition devices based on the resistance of specific materials are also known. These devices are manufactured using technologies that do not provide reliable spatial resolution (US 4 734 034, US 4 856 993, US 5 505 072, US 5 989 700, US 2011/226069) .

Overview The present invention particularly starts from the principle of determining a three-dimensional contour of an interval based on a set of two-dimensional measurements plus the magnitude of the pressure, i.e. measuring the pressure at an identified location of the interval. It is proposed to overcome these drawbacks by measuring the physical spatial dimensions (length, width, thickness).

  More specifically, starting from a flat sensor, for example, an object is applied to the sensor at a location determined with respect to x, y by applying pressure (to the sensor) on the opposite side. The third dimension then correlates with the pressure present in the plane of the sensor (with respect to x, y), so it is possible to determine the third dimension (with respect to z).

  When the finest measurement is required by allowing the replacement of statistical data such as pressure and static data such as length, which further requires a reference surface to measure, the present invention With a system that can perform accurate three-dimensional measurements on the order of micrometers using a single flat sensor and that only requires a small amount of spacing.

  For this purpose, the present invention is essentially a system for determining at least part of the shape of a three-dimensional object, which is a sensing member that detects a pressure region arranged so that the object can be applied to it. A means for calculating a distribution of the measured pressure to determine the shape from the measured pressure and a detection member; a means for applying the calculation means; and an object to the detection member with a uniform pressure; The sensing member includes a portion comprising a sheet of flexible plastic material integrated with a grid of pressure sensors, the grid having a thickness of 50 nanometers or less. A system is proposed that includes an intermediate layer having a resistivity that varies with pressure, including a semiconducting microcrystalline silicon wafer having a thickness.

  Due to the inherent flexibility of the sensor and its thinness, a portion of the shape of the interface between the two objects can be determined without interfering with the measurement.

  Note that layers and / or wafers, which are typically of different thicknesses, are, in contrast, constant or substantially constant thickness.

In an advantageous embodiment, one or the other of the following arrangements is further utilized.
A grid, generally parallel, referred to as a row electrode, referred to as a row electrode, a first layer comprising a first array of metal electrodes, the second intermediate layer, and a row so as to form the sensor; And a third layer containing a second array of metal electrodes, referred to as column electrodes, defining an area referred to as an intersection area with the electrodes.
The electrode metal is aluminum;
The first layer comprises more than 100 row electrodes and the third layer comprises more than 50 column electrodes.
The thickness of the first layer is between 150 nm and 500 nm, the thickness of the intermediate layer is between 80 nm and 250 nm, the thickness of the wafer is less than 30 nm, The thickness is between 350 nm and 700 nm.
The grid comprises at least 5000 sensors adjacent to each other having a square cross section of 600 micrometers or less;
The intermediate layer is formed by plasma deposition of doped silicon under the insulating layer;
The connecting element comprises a pin connecting to the support part;
The calculating means comprise means arranged to dynamically display the shape of the object on the computer screen by integrating the additional data;

  The present invention is also a method for measuring the shape of a three-dimensional object, wherein the object is applied to a detection member connected to a calculation means for detecting a pressure region, and the pressure is 600 micron. Measured by a sensing member comprising a sheet of flexible plastic material adhered to a grid of pressure sensors comprising at least 5000 sensors adjacent to each other having a square cross section of less than a meter. The grid includes an intermediate layer having a resistivity that varies with pressure, the intermediate layer including a wafer of semiconducting microcrystalline silicon having a thickness of 50 nanometers or less, and the shape is measured We propose a method that is calculated based on the distribution of pressure.

  Advantageously, the shape of the object is dynamically displayed on the computer screen by integrating additional data.

  The invention will be better understood on reading the following description of an embodiment given as a non-limiting example. The description refers to the following accompanying drawings.

1 is an overall view of a measurement system according to an embodiment of the invention specifically described herein. FIG. FIG. 2 is a partially enlarged exploded perspective view of the sensing member of the system of FIG. 1 (the proportions between the various elements are not to scale). FIG. 3 illustrates the steps of making the pressure sensor of the sensing member of FIG. 2 (in top view and cross-sectional views AB). 1 is a schematic partial plan view illustrating a sensor grid according to an embodiment of the invention specifically described herein. FIG. 4 shows experimental measurement curves for changes in the magnitude of electricity as a function of sensor deformation for four sizes of sensors. FIG. 2 is a schematic view of an acquisition board belonging to a connection element of the system of FIG. FIG. 4 is a simplified flow diagram illustrating the main steps of a method according to an embodiment of the invention. 2 is a diagrammatic representation of a cross section of an object applied to a sensing member by two different pressures. 2 is a diagrammatic representation of a cross section of an object applied to a sensing member by two different pressures.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a system 1 for determining at least part of the shape of a three-dimensional object 2.

  The system 1 includes a calculation and graph display means 3 suitable for calculating the measured pressure distribution and determining the shape therefrom.

  The means 3 includes a computer 4 connected by a connecting means 5 to a detection member 6 that detects the pressure region 7.

  The detection member 6 is flat and is arranged such that the object 2 may be applied by placing the object 2 on a flat upper surface 8, for example.

  The system 1 includes means 9 for applying the object 2 to the sensing member 6, which means 9 is accurately positioned with the sensing member 6.

  These application means 9 apply a force F on one side or surface 10 of the object as opposed to the side or surface on which it is desired to determine the shape. The side 10 is arranged to have a shape complementary to the pressure surface of the application means so that the force applied to the object is evenly distributed. The side surface 10 is formed by a flat surface, for example.

  The means comprises, for example, an actuator cylinder (not shown) comprising a horizontal plate 11 which is arranged parallel to the flat surface 8 of the sensing member and interacting with the flat surface of the side surface 10.

  The resulting pressure arises from the force F and is applied uniformly to the object by the application means 9. The pressure is determined and monitored by calculation means (dashed line 12).

  The detection member 6 abuts partly (for example 95%) or completely in a measurable manner on a fixed support table 13 suitable for causing the sensor member to absorb the pressure applied by the application means 9.

  The detection member 6 is in the form of a flat plate or portion 14 having a rectangular parallelepiped shape, for example.

  The dimension of the plate is, for example, 15 cm × 15 cm, and in the example selected here, the total thickness of the plate is approximately 800 μm.

  More particularly, referring to FIG. 2, the portion 14 includes a support sheet 15 made of a plastic material, eg, flexible polyethylene naphthalate (PEN), adhered to the grid 16 of the pressure sensor 17.

  The term “flexible” is understood to mean a plate capable of receiving a radius of curvature of less than 1.5 mm.

  The support sheet 15 is a rectangular parallelepiped having a size substantially equal to or smaller than the size of the plate.

  Portion 14 includes a fine layer 18 having a thickness equal to that of sheet 15, for example made of silicon nitride, made of ceramic, for example, having a thickness of 100 micrometers and bonded to sheet or PEN 15.

  The assembly thus formed includes a first layer 19 that includes a first array of electrodes 20, 20 ', referred to as row electrodes, at the top.

  Each electrode is a conductive metal wire, for example made of aluminum, with a flattened and elongated rectangular cross section.

  The width of the electrode is less than 2 mm, for example 0.5 mm, and the thickness is for example between 150 nm and 500 nm, for example between 200 nm and 400 nm, for example 300 nm.

  Thus, the array of electrodes is formed from a bundle of row electrodes that are substantially parallel to each other and spaced apart by a width of less than 2 mm, for example 0.25 mm.

  In the embodiments specifically described herein, the number of row electrodes is greater than 100, for example 120, operating in pairs 20, 20 '.

  Conductive elements 21 and 22 are also provided and described in detail below.

  The intermediate layer 23 is located on the first layer 19 of row electrodes.

  This intermediate layer 23 includes a semiconductive layer or wafer 24 of piezoelectric material. The piezoelectric material is semiconductive microcrystalline silicon (eg doped with arsenic).

  Wafer 24 was associated with an array of row electrodes and a spacing 26 therebetween with a substantially uniform thickness between 30 nm and 100 nm by forming an electrical bridge between the parts described in detail below. Cover portion 25.

  The spacing between the two pairs of row electrodes 20, 20 'does not include a layer of semiconductive material.

  The intermediate layer 21 further includes a layer 27 of electrically insulating material on the semiconductive layer 24.

  The lateral and longitudinal dimensions of the layer 27 are equal to the dimensions of the plastic sheet, and its maximum thickness is between 50 and 250 nm.

  Layer 27 completely covers first layer 19 and semiconductive layer 24 of electrodes 20, 20 ', away from defined location 28, which will be described in detail with reference to FIGS.

  The resistivity of the intermediate layer 21 formed in this way varies according to the pressure and / or deformation applied to the intermediate layer.

  Sensing member 6, and more particularly portion 14, also includes a third layer 29 above the intermediate layer 23 that includes a second array of metal electrodes, referred to as column electrodes 30.

  The column electrode 30 is, for example, a row electrode, but can be arranged such that the row and column array overlap forms a grid.

  For example, the two arrays define an area referred to as the intersection area with the row electrodes so as to form a pressure sensor 17 that is substantially orthogonal to each other and bonded to the plate.

  Advantageously, the gap is filled so that the neutral (insulating) protective layer 31 (dashed line in FIG. 2) has a flat surface 32 arranged to interact with the object to be measured. Protect the top of the.

  The thickness of the column electrode is between 400 nm and 600 nm, the number of which is more than 40, for example 54.

  In the embodiment specifically described herein, this number is greater than 4000, for example 6480, since the number of sensors 17 is equal to the number of intersections on the grid. Thus, the grid includes at least 5000 sensors adjacent to each other and the intersections are orthogonal, so that the cross section of the sensors is square and no more than 600 micrometers.

  With reference to FIGS. 3A-3D, a method of fabricating a sensor member according to one embodiment of the present invention will now be described.

  The method includes a first step (FIG. 3A) of providing a first substrate made of polyimide in the form of a plastic film, such as that sold by DuPont Teijin Films, to form a support sheet 15.

  This forms, for example, a substantially rectangular parallelepiped plate having a rectangular cross section of 15 cm × 15 cm or less and a thickness of less than 125 μm, for example less than 50 μm (for example, 10 cm × 10 cm × 10 μm).

  Advantageously, the plates are freed of impurities by washing an ultrasonic bath with acetone and rinsed with ethanol or isopropanol in a manner known per se.

A second step of depositing a ceramic layer 18, such as silicon nitride, is subsequently performed. It takes the form of, for example, plasma enhanced chemical vapor deposition (PECVD). The gas phase of PECVD is composed of a mixture of silicon tetrahydride (SiH ₄ ), known as silane, nitrogen (N ₂ ), and hydrogen (H ₂ ), and is performed at a temperature of less than 200 degrees, for example, 165 degrees. Is done.

  The desired silicon nitride layer thickness is less than 100 nm, for example 50 nm.

  A third step of depositing an array or layer of row electrodes 20, 20 'over the ceramic layer 18 is subsequently performed.

  Vapor deposition is performed by electron beam lithography or by evaporation by the Joule effect to make metal row contacts with a thickness greater than approximately 300 nm.

The contact is subsequently etched by wet etching. For example, the sample is immersed in an aluminum bath (about 50 degrees) with an etchant, such as phosphoric acid (H ₃ PO ₄ ), for a determined time. This determined time can be approximately 2-3 minutes.

The sample is subsequently rinsed with distilled water and dried with a stream of N ₂ gas.

  In the embodiments specifically described herein, the metal contacts include a first row electrode 20, a second row electrode 20 parallel to the first column electrode, and a first contact pad 21 and a second contact. A pad 22 is included.

  The first contact pad 21 is substantially a rectangular parallelepiped, is connected to the first electrode 20, is orthogonal to the electrode, and extends at a distance between the pair of electrodes 20, 20 ′.

  The second, square pad 22 is positioned in the plane of the end portion of the first pad 21.

  An intermediate layer 23 is formed in the fourth step (FIGS. 3B and 3C).

  The manufacturing method includes a sub-step of depositing a semiconductor piezoelectric layer 24.

  The piezoelectric layer 24 completely covers the row electrode pads 21, 22 and fills the space between the two electrode pads 21, 22 of the same pair.

Deposition is carried out by PECVD, for example by depositing microcrystalline arsenic (AsH ₄ ) doped silicon nitride with a thickness of about 130 nm.

The method subsequently involves photolithography. The etching is carried out using methods known to those skilled in the art under the name of reactive ion etching (RIE) using sulfur hexafluoride plasma (SF ₆ ).

  Therefore, the intermediate layer is formed by depositing added silicon under the insulating layer by plasma.

  The second sub-step in forming this layer consists of depositing a layer of electrically insulating material. This layer has a maximum thickness of 300 nm.

  This layer includes a through hole 28 on the same line as the second pad 22 of the first row electrode array layer.

The insulating material is, for example, silicon oxide (SiO2). The insulating material is deposited, for example, by sputtering, and then involves photolithography. Etching is performed by reactive ion etching RIE using SF _6.

  In a fifth step (FIG. 3D), the deposition of a layer made of aluminum, for example having a thickness of 500 nm, called the third layer, of column electrodes 30, 30 ′, using Joule effect evaporation is used. Is then started, and photolithography is performed to make the second metal column contact 22 in an array orthogonal to the array of rows.

  The array is arranged so that a row of a pair of column electrodes 30 passes on the same line as the first contact pad 21 and the second contact pad 22.

  One of the pair of column electrodes 30 is directly positioned on the insulating layer 27, the piezoelectric layer 24, and the first contact pad 21.

  The other is directly collinear with the piezoelectric layer 24 and the second contact pad 22.

  Wet etching techniques are used here, for example, as described above.

  In one embodiment of the present invention, the previously obtained assembly is thermally annealed at a low temperature (eg, less than 200 degrees, eg, 180 degrees) for a determined time, eg, 2 hours in an oven. This improves the microcrystalline silicon / aluminum interface and increases the conductivity by more than 1.5 times or 2 times.

  FIG. 4 schematically shows the arrangement of the pressure sensors 17 forming part of the detection member 6.

  In the embodiments specifically described herein, each row electrode 20 is repeated by offset parallel electrodes 20 ', allowing geometric flexibility in the formation of the sensing member.

  Accordingly, the two electrodes 20, 20 'form a pair of electrodes.

  Each row (one of the pair) and column electrode is connected to a connection pin 33 known per se which rests on the support part and forms a connection element.

  There is a single electrical connection pin 33 for a given row or column.

  The electrical measurement principle will now be described.

  A voltage is applied between the row pins 20 and the column pins 30, for example.

  The magnitude of the current is measured at one of the pins and depends on the electrical resistance on the electron path according to Ohm's law.

  As pressure is applied to the pressure sensor, the geometry of the piezoelectric layer changes with electrical properties, including resistivity.

  Since electrical contact can be made between rows and columns only through the through-holes of the insulating layer by the piezoelectric layer, electrical measurements can be tied to geometric data.

  The electrical resistance value of such a material changes during physical deformation according to the following equation:

  Where ΔR is the change in electrical resistance between the initial resistance and the final resistance, R0 is the initial electrical resistance, FG is the gauge factor (a constant characteristic of the piezoelectric material), ε (epsilon) is a deformation of the material that can be combined with external pressure.

  More specifically, considering the dominant properties of PEN and silicon nitride Young's modulus (270 GPa and 6.45 GPa, respectively) relative to the other layers, the model just described is between two layers of silicon nitride. In relation to the sandwiched layer of PEN, the thickness of each of the layers is, for example, 125 μm for PEN and 550 nm and 250 nm for the two layers.

  Therefore, a model that combines deformation and measured resistance is obtained according to the following equation:

Where ε is the material deformation and d _s , d _f1 , and d _f2 are the respective thicknesses of the PEN and silicon nitride layers.

Where Y _t and Y _f are the Young's modulus (Y _s ) of the substrate, ie 2.5 GPa, and the Young's modulus (Y _f ) of the silicon nitride layer, ie 270 GPa.

  By choosing this limit, the calculation relating pressure to the difference in measured resistance is always shown with the linear nature of the experimental reading of the change in current as a function of deformation, with the same slope. (FIG. 4A), simplified.

  The horizontal axis represents strain epsilon as a percentage, and the vertical axis represents the relative change in current. The four values are obtained by changing the width (W) for the same length (L) or vice versa. Due to this limitation, measurement accuracy of approximately micrometers can be obtained.

  In the embodiment specifically described herein, the device includes acquisition means 5 (FIG. 5). These acquisition means include an acquisition substrate 34 on which a module 35 for multiplexing / demultiplexing information emitted by rows 36 and columns 37 is mounted.

  The substrate also includes adaptation means 38 for adapting the electrical signal to be provided to the analog / digital converter 39/40 to allow processing by the computing means 3, and a module for communication of the substrate with the computer 4 41 is included.

  Each pressure measurement has two resistivity measurements, a first measurement, referred to as an initial measurement where no measured pressure is applied, and a second measurement where the measured pressure is applied to the object. Including.

As an example, the measurement of each sensor 17 may be performed according to the following pattern.
By randomly obtaining data (requesting by applying a voltage to the corresponding pin) until all data is obtained from any sensor present.
By obtaining data from all of the sensors in a given column or row until data is obtained from all of the columns or rows.
-By obtaining data from a specific area.

  Acquiring measurements and determining at least a portion of the shape of a three-dimensional object, according to one embodiment of the present invention, will now be described with particular reference to FIGS. 6, 7A, and 7B. .

  In a first step 42, the object whose shape is desired to be determined is placed on the plate 14 of the horizontal detection member 6 below the application means 9.

  The operator triggers the start of the shape determination process, for example via the computer 4, and operates the actuator cylinder to bring the plate 11 into contact with the object and apply a uniform pressure thereon.

  Following the actuator cylinder descent and / or in conjunction with the descent, a first pass of measurement of all sensors (step 43) is performed and the result is, for example, “row 5−column 27−initial−28 (MΩ ) ”In the form of“ mega ohms ”.

  The actuator cylinder (step 44) then applies and maintains the determined pressure evenly on the side 10 of the object 2 in contact.

  The computing means 3 then commands a second measurement for all or part of the pressure sensor (step 45).

  The result of the measurement is also input into the memory of the computer, for example in the form of “row 5−column 27−measurement 1-245Ω ohm”.

  The calculation means can use the internal characteristics of the detection member (particularly the material thickness and Young's modulus), which are input to the computer in advance, and the initial position and under pressure for a given pair of (row / column) coordinates. From these, the pressure applied to the plate is then measured for each pair of coordinates (step 46).

  Then, for each spatial coordinate in the plane, the computing means associates the value of the resistance, and consequently the pressure difference, at 47, and then establishes the pressure intensity region and then, at 48, known per se. The results are displayed on a computer screen using software means for presenting the data.

  The strength of each pressure corresponds to the amount of deformation and penetration of the object into the thickness of the detection plate.

  In more detail, referring to FIGS. 7A and 7B, a measurement that allows the contour 49 of the object 2 indented into the plate 14 is shown schematically.

  If the contour portion 50 remains outside the thickness of the plate (FIG. 7A), a larger object-indented portion 51 is created to determine the complete shape in the plane of the interface (eg to the computing means 3). Monitored) and greater pressure can be applied (FIG. 7B).

  The applied pressure (arrow 52) is negotiated to be below the determined limit as well as the elastic deformation limit of both, particularly with respect to the resistance of the object and the sensor material.

  In one embodiment of the invention, the computing means includes means arranged to dynamically display the shape of the object on the computer screen by integrating additional data.

  The shape of the object appears directly on the user's screen.

  In addition, the second pressure measurement (step 45) may be repeated (test 53), for example at a refresh rate greater than 100 Hz, so as to comprise a dynamic determination of the shape of the object.

  Needless to say, and as a result of the foregoing, the present invention is not limited to the specifically described embodiments. On the contrary, all variants, in particular those in which the pressure application means are designed in a shape substantially complementary to the upper surface of the object, the pressure application means is not flat or (integrated pressure gradient via computing means) A variant formed by push fingers (without or integrating), a variant in which the pressure application means moves on the object by adjusting itself with respect to the distance to the part of the object facing the application means, an intermediate layer Variations that are stacked upside down, variations in which the electrodes operate as a single electrode without forming a pair of electrodes, or variations in which the plate 14 is made using different methods are included.

Claims (11)

  A measurement system (1) comprising a detection member (6) for detecting a pressure region arranged so that an object can be applied thereto, said detection member (6) being a grid (19) of a pressure sensor (17) ), And the grid includes an intermediate layer having a resistivity that varies with pressure, wherein the pressure is in the form of a three-dimensional object (2). An element (5) for connecting the sensing member with means (3) for calculating the distribution of the measured pressure to determine the shape from the measured pressure, to be applied to determine at least a part, Including a computing means (3) and means (9) for applying the object to the sensing member, comprising a sheet (15) made of a plastic material part of which is integrated with the grid, and an intermediate layer of 50 nanometers Thickness below meters System according to claim, and include a semi-conductive microcrystalline silicon wafer having a.   A first layer (19) comprising a first array of metal electrodes (20), referred to as row electrodes, in which the grid is generally parallel, the second intermediate layer, and the sensor A third layer including a second array of metal electrodes (30), referred to as column electrodes, defining an area referred to as an intersection area with the row electrodes to form. The system according to claim 1.   The system of claim 2, wherein the electrode metal is aluminum.   4. A system according to any one of claims 2 and 3, wherein the first layer comprises more than 100 row electrodes and the third layer comprises more than 50 column electrodes.   The thickness of the first layer is between 150 nm and 500 nm, the thickness of the intermediate layer is between 80 nm and 250 nm, the thickness of the wafer is less than 30 nm, and the thickness of the third layer The system according to any one of claims 2 to 4, characterized in that is between 350 nm and 700 nm.   6. A system according to any one of the preceding claims, wherein the grid comprises at least 5000 sensors adjacent to each other having a square cross section of 600 micrometers or less.   7. A system according to any one of the preceding claims, characterized in that the intermediate layer is formed by plasma deposition of doped silicon under the insulating layer.   8. System according to any one of claims 1 to 7, characterized in that the connecting element comprises a pin for connecting to the support part.   9. A method as claimed in any preceding claim, wherein the computing means includes means arranged to dynamically display the shape of the object on the computer screen by integrating additional data. The system described in the section.   An object is applied to a sensing member that senses a pressure region, the pressure is measured by a sensing member comprising a flexible part integrated with a grid of pressure sensors, and the grid changes in response to pressure. Measuring method comprising an intermediate layer having a method wherein the method is applied to determine the shape of a three-dimensional object, the member is connected to a computing means, and the part is bonded to a sensor grid A semiconducting micrometer comprising a sheet of plastic material, the grid comprising at least 5000 sensors adjacent to each other having a square cross section of 600 micrometers or less, and wherein the intermediate layer has a thickness of 50 nanometers or less. A method comprising: including a crystalline silicon wafer; and a shape is calculated based on a measured pressure distribution.   The method of claim 9, wherein the shape of the object is dynamically displayed on a computer screen by integrating additional data.