S P E C I F I C A T I O N
DEVICE FOR ESTIMATING VOLUME
FIELD OF THE INVENTION
The present invention pertains to mechanical devices, in particular mechanical devices for estimating the volume of solids, more particularly, irregular solids.
BACKGROUND OF THE INVENTION
The development of cancer drugs requires researchers to determine the efficacy of potential cancer treating agents. Although initial screens for such agents are most easily performed using panels of cell lines, follow up studies using animal models provide more relevant data on the anti- tumorigenic effect of promising treatment regimens . After administration of these agents to animals harboring various cancers, researchers surgically remove the malignant tissue and measure changes in the tumor volumes relative to untreated controls. The effectiveness of an agent is directly related to its ability to reduce these tumor volumes. Consequently, effective drug discovery rests on fast and accurate tumor volume measurement .
Additionally, clinicians can often use tumor size to stage the progression of cancers in patients. Since different stages may respond best to particular treatments, successful patient care depends on rapid and accurate determination of tumor volume .
One currently available method for estimating tumor volume involves extrapolation from three dimensional measurements of the tumor, (i.e. length, width and height) . By assuming that the tumor closely approximates a symmetrical solid, such as a cube, a researcher can then calculate its volume based on a mathematical formula: Volume - (length x width x height)
However, the shape of the tumor can significantly affect the quality of the data derived from this method. For example, highly asymmetrical or irregular tumors, which are quite common, are clearly not well suited for this technique. Additional sets of measurements may improve the accuracy of tumor volume calculations in these situations, but such measurements require valuable research time.
In addition to the problems associated with irregular tumors, variations in precision, i.e., reproducibility, of measurements, can result from non-uniform technique. That is, three dimensional measurements such as those mentioned above are usually carried out using a caliper, the ends of the legs of which are contacted with the tumor then removed and the distance between the ends of the legs measured. How hard the ends of the legs of the caliper are pressed into the relatively soft tumor tissue will affect the measurement. This is particularly true when more than one technician, each of whom has his or her own technique for taking the measurement, are involved. A method for tumor volume estimation that reduces or eliminates this type of potential error is needed.
In an alternative method, researchers can obtain the volume of a tumor by measuring its mass, and then calculating its volume by assuming its density. While this approach does not require the tumor to possess any particular shape, it fails to adjust appropriately to variations in the density of the excised tissue. Moreover, this technique requires that the tumor be surgically removed and therefore cannot be used by clinicians to stage various skin lesions, such as melanomas or dysplastic nevi, prior to their removal. Additionally this method is painful to the patient potentially resulting in other physiological problems.
Accordingly, there is a need for a device that will afford a rapid, reproducible estimate of the volume of tumors and other tissue masses, that accommodates various shapes and sizes of tissue, and that generally overcomes the foregoing problems .
SUMMARY OF THE INVENTION
The present invention provides such a device. In a first aspect, the device of the present invention relates to the estimation of the volume of a regular or irregularly shaped solid object, such as, without limitation, a solid tumor, by mapping the three dimensional surface of the object, translating this map into a corresponding linear displacement and calibrating this linear displacement to a measurement of the object's volume, thus providing a quick, simple, and in the case of a subcutaneous tumor, non-invasive, way to measure the volume of a solid.
As used herein, the terms "estimate", "estimating", "estimation", "measure", "measuring", "measurement" and the like, refer to the obtaining of an approximation of the volume of a solid.
The volume measuring device of the present invention includes a structure to map the three dimensional geometric shape of an object and a corresponding device to convert this geometric image into an equivalent measurement of the object's volume .
In a preferred embodiment, the mapping structure includes a cylindrical chamber with top and bottom surfaces made from a flexible and resilient material. Housed within this chamber are a number of elongate pins. These pins are held in place between the top and bottom surfaces of the chamber. As the mapping structure is pressed over a solid object, as for example a tumor, the three dimensional shape of the object is mapped into the flexible bottom surface of the chamber. The pins within the chamber translate this shape onto the top surface of the chamber. Attached to, and in dynamic contact with, the top surface of the chamber is a volume converter which translates the three-dimensional shape outlined in the top surface into a corresponding linear displacement. This linear displacement is calibrated to represent the precise volume of the object being measured.
In an alternate embodiment, the volume converter is a chamber which includes a lower portion housing a liquid filled balloon and an upper portion housing a sliding indicator. The displacement of the mapping chamber into the lower portion of the volume converter causes the balloon to push the sliding indicator within the upper chamber. This linear movement of the sliding indicator can be calibrated to equate to the corresponding volume of the object being measured.
Alternatively, the volume converter can include a liquid filled chamber with a floating indicator. The displacement of the mapping chamber into the liquid filled chamber causes the level of the liquid to rise. The float similarly rises and this linear displacement can be calibrated to equate to a corresponding volume of the object being measured. Similar to the above embodiment, the volume converter can include a hermetically sealed chamber with a pressure sensitive indicator. The displacement of the mapping chamber into the sealed chamber causes the level of the indictor to rise. The level of the indicator can be calibrated to equate to a corresponding volume of the object being measured.
Preferably, the volume measuring device is incorporated into an ergonomically designed handle which includes an electronic device to more precisely measure the linear movement in the volume converter. In this embodiment, an electronic level indicator and level sensor are included on the volume converter and these measurements are automatically transmitted to a digital readout on the handle and/or downloaded to a computer system.
An additional embodiment of the mapping chamber and volume converter includes a completely electronic configuration. In this embodiment the displacement of each of the pins is measured with a sensor. The sensor take the form of a laser light, ultrasonic transducer or any comparable device which can accurately determine the distance to an object. These measurements are then computed in a processor and equated to a corresponding volume of the object. Similar to the previous example, this electronic version of the volume
measuring device can be incorporated into an ergonomically designed handle with a digital readout of the volume measurement. The resulting measurement can similarly be downloaded into a computer system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general perspective view of a volume measuring device .
FIG. 2 is a perspective view of a preferred embodiment of the volume measuring device with the internal components shown in more detail.
FIGS. 3A & 3B show the operative details of the object mapping structure of the present invention.
FIG. 4 is an alternate embodiment of the volume measuring device of the present invention.
FIG. 5 is a perspective view of the volume measuring device of the present invention with an integrated control handle .
FIG. 6 is a top view of the control handle showing the components of the electronic display.
FIGS. 7A - 7C show an alternate embodiment of the object mapping chamber and volume converter where an electronic sensor is incorporated into the mapping chamber.
FIG. 8 is another alternate embodiment of the volume measuring device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, the invention will be described in detail. With attention first to FIG. 1, a general perspective view of the volume measuring device 10 of the present invention is shown. The volume measuring device 10 has a housing 12 which forms the outer structure of the invention. The volume measuring device 10 includes an object surface mapping structure 14 which is used to accurately map the outer surface of an object, as for example a skin tumor.
The bottom surface 16 of the mapping chamber 14 can be inwardly displaced when pressed over a solid object such as a tumor. The displaced volume of the solid object is translated via a volume converter 18 into a corresponding linear displacement. This linear displacement is then displayed within a volume display area 20. In a preferred embodiment of the present invention, a level indicator 64 registers the corresponding volume displacement using a calibrated scale 66 marked on the side of the volume display area 20. Turning now to FIG. 2, a detailed cutaway perspective view is shown of a volume measuring device 10 of the present invention. The volume measuring device, shown generally as 10, includes a housing 12. The housing 12 is preferably formed from a molded plastic material suitable for use in clean applications such as medical diagnostic and testing procedures . The housing 12 serves as a general enclosure for the various components of the volume measuring device 10. The volume measuring device 10 further includes an object surface mapping structure 14 located at the distal end 10a of the volume measuring device 10. In a preferred embodiment as shown in FIG. 2, the mapping structure 14 is essentially cylindrical in shape and includes a bottom circular surface 16 and a top circular surface 28. However, the shape of the object mapping chamber can vary to accommodate variously sized objects. The bottom surface 16 is preferably made from a membrane of a flexible and resilient material such as a high quality surgical latex. The physical qualities of the bottom surface membrane 16 are such that when pressed over a solid object, the membrane will conform to the three-dimensional shape of the object. Alternatively, When the bottom surface membrane 16 is removed from the same solid object, it will return to its original size and shape. The mapping structure top surface 28 is made from a similar flexible resilient material as that of the bottom surface 16. Housed within the mapping structure 14, between the top surface 28 and the bottom surface 16, are a plurality of elongate rigid pins 30. Each of the pins 30 has a proximal
end 32 and a distal end 34. The proximal end 32 of each pin is in contact with the top surface 28 and the distal end of each pin is in contact with the bottom surface 16. Each pin 30 is essentially normal to the top 28 and bottom 16 surfaces and each pin 30 is essentially parallel and equidistant from the other pins 30.
When the bottom surface 16 is pressed over a solid object, the pins 30 translate the resulting inward displacement of the bottom surface 16 into a corresponding and equivalent outward displacement of the top surface 28. The inward displacement of the bottom surface 16 and the equivalent outward displacement of the top 28 surface represents a measurement of the volume of the solid object being pressed into the mapping structure 14. The accuracy of this measurement is directly related to the number of pins 30 within the mapping structure 14. Since each pin 30 represents a discrete point on the three-dimensional surface of the solid object, the more pins that are used, the more accurately the pins can approximate the smooth surface of the object. The term "correspondingly responsive" as used in describing the top and bottom mapping surfaces of the object mapping chamber is meant to describe both mechanical embodiments as presently being described as well as electronic embodiments which will be described in further detail below. "Correspondingly responsiveness" generally describes the ability to gather data of an objects shape at one location and having that data shape data simulated in another location. Located directly adjacent to the top surface 28 is a volume conversion area 18. The volume conversion area 18 is preferably cone shaped. Fitted within the volume conversion area 18 is a fluid filled balloon 22. The balloon 22 is preferably made from latex or some other durable, flexible and resilient material. The balloon 22 has the same general shape as the volume conversion area 18 and is sufficiently filled with liquid so as to fit snugly within the area 18. The bottom surface 26 of the balloon 22 is in direct contact with the top surface 28. The proximity of the balloon 22 to the
top surface 28 allows the resulting force from the outward displacement of the mapping structure top surface 28 to be translated into the balloon 22. The top surface 24 of the balloon 22 is then displaced a corresponding distance into the volume display chamber 20. The combination of the mapping structure 14 and the volume conversion chamber 18, translates a volumetric displacement of an object into a linear displacement . This linear displacement can then be calibrated to indicate the corresponding volume of the object being measured. The combination of the conversion chamber 18 and the display chamber 20 define the volume converter of the present invention.
A volume indicator, shown generally as 50, correlates the linear movement of the top surface 24 of the balloon 22 into a readable volume measurement. The volume indicator 50 is mounted within the volume display chamber 20 and includes a rod 52 which has a lower end 54 and an upper end 56. The lower end 54 of the rod 52 is seated against the upper surface 24 of the balloon 22. The upper end 56 of rod 52 is connected to an adjustable mounting knob 82 via a spring 84. The tension exerted by the spring 84 on rod 52 enables the lower end 54 of the rod 52 to be kept in constant contact with the top surface 24 of balloon 22. A tension adjustment knob 86 is located on the outside of cap 80 for adjusting the force that the rod 52 places on the top surface 24 of balloon 22. Adjustment knob 86 is also used to make calibration adjustments to the position of rod 58. Cap 80 is screwed onto the top of the volume display chamber 20 and allows access to the components located within the volume display chamber 20. The volume indicator 50 also includes a lower cap 58 mounted proximate to the lower end 54 of rod 52 and an upper cap 60 mounted proximate to the upper end 56 of rod 52. Caps 58 and 60 are concentrically mounted on rod 52 and act as guides to keep the rod 52 centered within the volume display chamber 20. The diameter of guides 58 and 60 are slightly less than the internal diameter of the volume display chamber 20 and are fabricated to slide freely within the chamber.
Fixed within the volume display chamber 20 is a stop plate 62. Stop plate 62 defines the lowest point that the rod 52 can reach. When cap 58 contacts stop plate 62, rod 52 is prevented from moving any further toward the top surface 24 of balloon 22.
Since the movement of the volume indicator 50 within the volume display chamber 20 causes displacement of the air inside the chamber 20, a breather hole 90 is provided in the wall of the volume display chamber 20 proximate to where the cap 80 is attached. The breather hole 90 allows air to enter and leave the chamber 20 so that the volume indicator 50 can freely move up and down with the movement of the balloon 22. Attached near the center of rod 52 is an indicator disk 64. The disk 64 provides a reference point for measuring the linear displacement of the rod 52 and the corresponding volume of the object being measured. A calibrated scale 66 is provided on the wall of the volume display chamber 20 to display the volume of the object being measured. The scale 66 is formatted to equate the linear displacement of the rod 52 to the volume of the object being measured. As the rod 52 moves within the display chamber 20, the disk 64 moves, incrementally past the markings of the scale 66.
With attention now on FIGS. 3A and 3B, a more detailed view of the object mapping structure 14 is shown. In FIG. 3A, the mapping structure 14 is shown prior to being pressed over an object 102. In a typical application, the present invention would be used to measure the volume of an object 102, which could be a tumor located on the surface of a person's skin 100. As described above, the mapping structure 14 is essentially cylindrical in shape and includes a bottom circular surface 16 and a top circular surface 28. However, the shape of the mapping structure 14 can be varied for different applications and this disclosure is not intended to limit the present invention to a cylindrical embodiment. The bottom surface 16 is preferably made from a membrane of a flexible and resilient material such as a high quality surgical latex. The physical qualities of the bottom surface
membrane 16 are such that when pressed over a solid object, the membrane will deform to the three-dimensional shape of the object 102.
Mounted within the mapping structure 14, between the top surface 28 and the bottom surface 16, are a plurality of elongate rigid pins 30. Each of the pins 30 have a proximal end 32 and a distal end 34. The proximal end 32 of each pin is in contact with the mapping structure top surface 28 and the distal end of each pin is in contact with the mapping structure bottom surface 16. Each pin 30 is mounted essentially normal to the top 28 and bottom 16 surfaces and each pin 30 is essentially parallel and equidistant from the other pins 30.
As the object mapping structure 14 is pressed over the tumor or other object 102, as shown in FIG. 3B, the pins 30 translate the resulting inward displacement of the bottom surface 16 into a corresponding and equivalent outward displacement of the top surface 28. The inward displacement of the bottom surface 16 and the equivalent outward displacement of the top surface 28 represent an estimated measurement of the volume of the solid object 102 being pressed into the mapping structure 14.
The accuracy of the outward displacement of the mapping structure top surface 28 as a measurement of the volume of the tumor 102 depends on the number and density of pins 30 located within the mapping structure 14. Since each pin represents a discrete geometric measurement of the tumor 102, the more pins 30 that are used, the more accurate the measurement of the tumor volume will be. With a high density of pins 30 within the mapping structure 14, the resulting outward displacement of the top mapping surface 28 will better approximate the three dimensional surface of the tumor 102. Of course, the addition of more pins 30 within the mapping structure 14 might add to the cost and complexity of the volume measuring device 10. Various devices, each with a different number of pins 30 and therefore different levels of accuracy can be made, with
the cost of each device being based in part on the number of pins 30 within the mapping structure 14.
With attention now on FIG. 4, an alternate embodiment of the volume measuring device of the present invention is shown generally as 110. The volume measuring device 110 includes a housing 112. The housing 112 is preferably formed from a molded plastic material suitable for use in clean applications such as medical diagnostic and testing procedures. The housing 112 is also preferably formed from a material that is conducive to an injection molding process. The housing 112 is a general enclosure for the various components of the volume measuring device 110. The volume measuring device 110 further includes an object mapping structure 114 located at the distal end 110a of the device 110. The mapping structure 114 is essentially cylindrical in shape and includes a bottom circular surface 116 and a top circular surface 128. However, the present invention is not limited to object mapping structure with cylindrical shapes and various other configurations are contemplated by the present invention. The top and bottom surfaces 116 and 128 are made of a similar flexible and resilient material as described previously in conjunction with FIGS. 2 & 3. Similar to the mapping structure 14 of FIG. 2, mapping structure 114 includes a plurality of pins 130 mounted between the top surface 128 and bottom surface 116. In the embodiment shown in FIG. 4, the top and bottom mapping surfaces are removably attached to the mapping structure 114 with clamps 136 and 138 respectively. The clamps 136 and 138 hold the top and bottom surfaces 128 and 116 in contact with the pins 130. Removal of the clamps 136 and 138 allows the pins 30 to be separated from the mapping chamber 114 so that they may be sterilized or otherwise maintained. In this embodiment, the pins 130 could preferably be secured into a single cartridge rather than using a plurality of loose pins. The assembly of pins 130 could simply be inserted back into the mapping structure 114 for re-assembly. In this embodiment, pin assemblies of varying accuracy could be used in the same device 110,
expanding the flexibility of the invention and allowing easier maintenance. The top surface 128 separates the pins 130 from a liquid reservoir 122. The reservoir 122 is preferably filled with water or some other viscous liquid and is continuous with a volume display chamber 120. Within the volume display chamber 120 is a volume indicator float 150. The float 150 is maintained in an upright position by a weighted ballast 152 attached to the bottom surface 154 of the float 150. Together, the reservoir 122 and the display chamber 120 make up the volume converter of the present invention.
As the object mapping structure 114 of the volume measuring device 110 is pressed over a tumor or other object, the resulting outward deflection of the upper surface 128 causes a corresponding rise in the level of the liquid in the reservoir 122. The rise in the liquid level causes the float 150 to similarly rise, being displaced linearly in relation to the volumetric displacement of the mapping structure top surface 128.
The top surface 156 of float 150 includes an indication element 164. The indication element 164 provides a reference point for measuring the linear displacement of the float 150 and the corresponding volume of the object being measured. A scale 166 is provided on the wall of the volume display chamber 120. The scale 166 is calibrated to display a linear indication of the volume of the object being measured. As the float 150 moves within the display chamber 120, the indicator element 164 moves incrementally past the markings of the scale 166.
Located proximate to the distal end 110b of the volume measuring apparatus 110, on the wall on the volume display chamber 120, is a breather hole 190. The breather hole 190 allows air to move freely into and out of the volume display chamber 120 so that a vacuum is not crated and the float is not restricted when moving up or down. Similar to the embodiment described above in FIG. 4, another arrangement could be constructed which does not utilize a liquid filled chamber. Alternately, the volume
display area 120 could be a hermetically sealed chamber with a level tube incorporated into it . A change in the internal pressure of the chamber resulting from the top mapping surface being displaced into the chamber would cause a calibrated indicator to rise. The calibrated indicator can then be associated with the volume of the object being measured.
With attention now on FIGS. 5 & 6 , the volume measuring device 10 of the present invention is shown as adapted to be used with an electronic interface, shown generally as 200. While the manual reading of the volume displacement as described in conjunction with FIGS. 2 and 4 can give a reasonable approximation of the volume measurement, it is preferable to incorporate an electronic device to automatically and more precisely measure the linear displacement of the volume indicator 50 or 150. As shown in FIG. 5, a level sensor 202 is mounted on the side of the volume display chamber. The level sensor 202 detects the axial displacement of the level indicator 203 which is attached to the volume display apparatus 150 and electronically translates this displacement into a corresponding volume measurement. The sensitivity of the level sensor 202 and level indicator 203 are such that extremely small variations in the linear displacement of level indicator 203 can be detected. The data read by the level sensor 202 is fed through data cables 204 and 208 into a computer terminal where the information is processed and recorded.
To further accommodate easier measurements and comfortable operation, the volume measuring device of the present invention is incorporated into an ergonomically designed handle 212. The handle 212 is shaped to comfortably fit into the hand of a user and includes an activation trigger 214 which can be programmed to perform several different functions. For example, the trigger could serve as a signal to send a volume measurement to the computer 210 after the volume measuring device has been properly positioned over the object to be measured. Connection device 206 provides a data
communication link from the volume measuring device to a personal computer 210.
Located on the top surface of the handle 212 is a display panel 240 which provides real time information from the level sensor. FIG. 6 shows a top view of the handle display panel 240 which in a preferred embodiment includes a combination of both alphanumeric displays and control buttons. A variety of functions can be controlled from the display panel, including the sending of information to the computer, sensitivity variations and control of the trigger 214 function. Referring now to Figs. 7A-7C, another alternate embodiment of the volume measuring device is shown. In this embodiment, the measurement of an objects volume is accomplished completely by electronic means. In this embodiment, the physical mapping of an objects three dimensional surface is accomplished in a similar fashion as the previously described embodiments, but the conversion of this object mapping into a corresponding volume measurement is accomplished by an electronic reading of the displacement of each individual pin. Referring specifically to FIG. 7A, a cross-sectional elevation of the object mapping chamber 314 is shown. The object mapping chamber 314 includes an interior support plate 318 which is located at approximately the midpoint of the object mapping chamber 314 and is positioned parallel to the top 328 and bottom 316 surfaces of the object mapping chamber. It is not crucial to the present invention to have the support plate 318 located equidistant from the top and bottom surfaces of the object mapping chamber. Minor variations in this position will not affect the operability of the invention. The support plate 318 includes a plurality of circular apertures 320, which position a plurality of elongate cylindrical pins 330 vertically within the mapping chamber 314. Each of the plurality of elongate pins 330 has a proximal end 332 and a distal end 334. The proximal end 332 of each pin preferably includes a flat perpendicular plate 336 which extends beyond the diameter of the pin. This plate 336 prevents the pin from moving past the support plate 318. The
"zero" position of the pins is defined as when a pin 330 is resting with its proximal plate 336 against the support plate 318. At this point, the pins 330 are in the bottom-most position and there is not any inward force to move them vertically into the mapping chamber 314. The distal ends 334 of the pins 330 have a similar perpendicular plate 338. The dimension of the distal perpendicular plate 338 is such that when all of the pins are at the "zero" position, the plurality of distal perpendicular plates 338 form a continuous and essentially smooth surface, forming the bottom surface 316 of the mapping chamber 314. The surface area of each of the distal plates 338 is uniform and is a known value.
With continuing attention on FIG. 7A, the top surface 328 of the mapping chamber 314 is defined by a plurality of electronic sensors 340. The sensors are arranged so that there is a single sensor aligned with each of the pins 330 and more particularly with the proximal plate 336 of each pin 330.
The sensors 340 preferably employ a laser light, ultrasonic transducer or other similar mechanism for accurately determining the distance between the sensor and an object.
Each of the proximal plates 336 of the pins 330 is preferably coated with a detecting material that efficiently reflects the energy being transmitted by the sensor 340. In this manner each sensor 340 can accurately determine the distance that each pin 330 has moved in response to an inward force on the bottom surface 316 of the mapping chamber 314.
By determining the height of each of the pins resulting from an object being pressed into the bottom surface 316, in combination with the known surface area of each distal plate 334, an approximation of the volume of the object 302 can be calculated. As an example, assume that the distal lip of each pin has a surface area of 1 square millimeter (mm) and that each of the pins labeled a - k in FIG. 7A are moved the following distance by an abject 302: a - l mm g - 3 mm b - 3 mm h - 2 mm c - 3 mm i - 1 mm
d - 4 mm j - 0.5 mm e - 3 mm k - 0 mm f - 2 mm The total distance is therefore 22.5 mm. The movement of each pin 340, represents the volume of a section of the object 302 with a cross sectional area equal to the surface area of the distal plate 338 of the pin 330 and a height equal to the vertical movement of the corresponding pin. In the above example, since each of the distal plates 338 has a surface area of 1 square mm and the total vertical movement of the 10 pins that are displaced is 22.5 mm, the resulting total volume of the object 302 is length (10 mm) x width (1 mm) x height (22.5 mm) or 225 cubic mm. Note that since pin "k" was not displaced, it does not have any effect on the total volume and it is not factored into to the above equation.
Each of the sensors 340 are connected by a wire 342 to a processor 350. The processor 350 interprets the information gathered by each of the sensors and computes the corresponding volume. This value is then transmitted to a unit similar to that described in conjunction with FIGS. 5 and 6. Alternatively, the volume values computed by the processor can be outputted to a computer.
Referring now to FIG. 7B, a top view of a portion of the support plate 318 is shown in more detail. The apertures 320 are sized to allow the pins 330 to slide within them easily while maintaining the pins 330 in a consistent vertical position. The distal end 332 of the pin 330 includes a perpendicular plate 336 which prevent the pin 330 from moving past the support plate 318.
Referring now to FIG. 7C, a top view of a portion of the top surface 328 of the mapping chamber 314 is shown in more detail. As described above, the top surface 328 is formed from a plurality of sensors 340 with each sensor corresponding to the position of each of the pins 330. FIG. 7C is shown in the same scale as FIG. 7C to illustrate how the sensors 340 and pins 330 are aligned.
Referring to FIG. 8, another alternate embodiment 410 of the volume measuring device is shown. In this embodiment a unitized pin assembly or a plurality of pins is not necessary and a gas can also be utilized in the volume conversion chamber 420. In this embodiment, the fluid or gas in the volume conversion chamber 420 is in direct contact with an object mapping surface 428. Also in this embodiment, it is not necessary to have an object mapping chamber with correspondingly responsive top and bottom mapping surfaces. Rather, a single mapping surface 428 can be utilized to translate the object mapping into the volume conversion chamber 420. An inward force on this single surface of the object mapping chamber will displace the fluid or gas in the volume conversion chamber. This displacement can then be calibrated to register a corresponding volume measurement of the object being measured. As indicated above, this embodiment can also be utilized with a volume conversion chamber that is not liquid filled but instead comprises a pressure sealed gas filled chamber 420. Attached to the chamber is a level tube 450 with an indicator 464 which reacts to changes in the internal pressure of the volume conversion chamber. The rise in the level of this indicator 464 can then be calibrated to register a corresponding volume measurement of the object being measured. Although the invention has been described and illustrated in the above description and drawings, it is understood that this description is by example only and that numerous changes and modifications can be made by those skilled in the art without departing from the true spirit and scope of the invention.