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D _ United States Patent [19] [11] Patent Number: Roper et a1. [45] [54] METHOD AND APPARATUS FOR 4,926,867 5/1990 MEASURING THICKNESS 0F FAT USING 4,928,014 5/1990 Rosenthal ......................... .. 128/664 INFRARED LIGHT [75] Date of Patent: May 14, 1991 Kanda et a1. ...................... .. 128/633 FOREIGN PATENT DOCUMENTS Inv¢m°rS= Alan R01)", Talent; Keith 0- 1297782 3/1987 U.S.S.R. ....................... .. 128/660.02 Johnson, Medford, both of Oreg- [73] Assignee: 5,014,713 1308319 5/1987 U.S.S.R. ....................... .. 128/660.02 Tarris Enterprises, Inc., White City, Primacy -Examiner-Lee S. Cohen Oreg. Assistant Examiner-Krista M. Pfaffle [21] AppL NOJ 446,054 .Zttgrney, lAgent, 0rF1'rm—Chernoff, Vilhauer, McClung tenze [22] Filed: [25] l 1 Dec. 5, 1989 [57] ABSTRACT cclis """"""""""" " A618 51203629138316???‘ A body fat thickness measuring device comprising a ' """"""""""""""""""" " 128/774 250/341’ ’ pair of infrared emitting diodes, one emitting a steady, low-intensity light, and the other emitting periodic, ‘ ' . [58] F‘eld of Search 4l2285/0633359663O4'22’32g41’ / [56] ’ ’ / ’ ’ ' References Cited high-intensity pulses of light, to be placed against the skin where the fat is to be measured. The device con tains an array of dCECCtOgS in the fc1>rm of infrarecil-serisli tive photo-transistors w ich are p aced against t e s 'n U'S' PATENT DOCUMENTS in predetermined locations near the two diodes, yet 3,671,858 6/1972 Knudsen et a1. . 4,633,O37 12/1986 Rosemhal 6* a1- 4,700,708 10/1987 New, Jr. et a1. .................. .. 128/633 shielded from ambient light. The detector array pro vides signals proportional to the amount of infrared light detected, and these Signals are summed and amp1i_ Emu“; 4:807’ 631 2/1989 H23: etaax' 128/633 tied, forming a composite signal. The amplitude of this composite signal, which is indicative of the thickness of 128/633 the layer of fat, is displayed on a digital readout device ‘(8191752 4/1989 Zelin ...... 4,850,365 7/1989 """"""""" Rosenthal ..................... .. 128/664 ' 4,880,304 11/1989 Jaeb et a1. ......................... .. 128/633 8 Claims, 2 Drawing Sheets 30 /12 16 POWER SUPPLY 20 20 20 2 1° / Q/ Q/o TIMER '18 O_/ 14/ 22 /24 A/D CONV. ) 28 SUM AMP. 25 DISPLAY
D  _  United States Patent  19    11  Patent Number   Roper et a1.   45    54   METHOD AND APPARATUS FOR  4,926,867  5 199...
US. Patent l May 14, 1991 . 12 , 5,014,713 30) P061512 SUPPLY _+ Sheet 1 0f 2 10 Qls 2'0 2o 20 / 18 9% d TIMER 0/ 14/ 22 A/D }‘ CONV. FIG. 1 SUM ) 28 AMP. A g; L V18 /24 25 DISPLAY / 1 » .1! 4 m 1|‘ FIG. 2 \ 28 I l 1 I 1 1 I j I 1 I 1 I I I I I I I I 1 I 1 I I I I I 1 L I I! o0 oo‘o 00 Q goC)0OOQ 0W0 O0 G O @ oooo}4z k }44 FIG. 3
US. Patent  l  May 14, 1991  .  12  ,  5,014,713  30   P061512  SUPPLY _   Sheet 1 0f 2  10  Qls 2 0 2o 20     18 9  d  TI...
1 5,014,713 METHOD AND APPARATUS FOR MEASURING THICKNESS OF FAT USING INFRARED LIGHT BACKGROUND OF THE INVENTION The present invention relates to measuring the thick ness of body fat. More speci?cally, the present inven tion includes a method and apparatus for non-invasively determining body fat thickness using infrared light. In today’s health conscious world, people are becom ing aware ?tness involves more than maintaining proper body weight as indicated by a bathroom scale. Muscle tissue is heavier, and generally more desirable than fat tissue, but a scale treats their weights the same. It is necessary to determine the amount of body fat to get an accurate indication of total ?tness. Body fat has been measured using many different techniques. By immersing a body in water, its total fat composition can be determined. A simpler technique involves measuring the thickness of fat at various loca tions on the body using a skinfold caliper. Unfortu nately, accurate results with a skinfold caliper require not only consistent operation of the calipers, but also require a second person to take the measurements in 2 his therefore a principal object of the present inven tion to provide a device for noninvasively determining the thickness of a layer of fat. It is a principal feature of the present invention to use infrared light to measure the thickness of fat. The foregoing and other objectives, features and advantages of the present invention will be more readily' understood upon consideration of the following de tailed description of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is general block diagram of an illustrative embodiment of a device for measuring the thickness of a layer of fat according to the present invention. FIG. 2 is a bottom view of the sensor of the device of FIG. 1. FIG. 3 is a elevational view of the sensor in contact with ?esh, taken along line 3-—3 of FIG. 2. FIG. 4 is a schematic diagram of a circuit for a device which embodies the present invention. DETAILED DESCRIPTION OF THE INVENTION locations where the person being measured cannot Referring to the drawings, in FIG. 1 a block diagram is shown of a meter 10 which embodies the present readily see the caliper reading if attempting to do the invention. The meter comprises a power supply 12, two measurement on him or herself. infrared emitting diodes (IREDs) 16 and 18, ?ve photo transistors 20, a summing ampli?er 22, an analog-to The measurement of fat layer thicknesses is also im~ portant to the meat packaging industry, with the result that various methods have been used to measure fat on animals. However, many of the fat measurement tech niques used in that industry are invasive and thus inap propriate for ?tness measurement purposes. For exam ple, Shigeo Tauchi et al. Japanese laid-open patent ap plication No. 56-160622 describes using colored ?lters digital (A/D) converter 24, and a display 26. The IREDs and the photo-transistors constitute a sensor 28 which is enclosed on all sides except its bottom by a light shield 30. The power supply 12 biases the ?rst IRED 16 to provide a steady, low-intensity infrared (IR) light. The timer 14 controls the second IRED 18 to provide periodic pulses of high intensity IR light. to optically determine the fat thickness for a butchered cross section of meat, and Knudsen et al US. Pat. No. 3,671,858 discloses a method of using a needle having Referring now to FIG. 2, the two IREDs 16 and 18 are positioned adjacent each other and are equidistant from each of the ?ve photo-transistors 20. The light electrical contacts to measure electrical resistances be 40 shield 30 surrounds the IREDs and photo-transistors on tween various layers of flesh. the four sides and top while allowing their bottom sur Yoshio Takemori Japanese laid-open application No. faces to be exposed. 60-181606, Hiroyuki Toyokawa Japanese laid-open ap The sensor 28 is shown in contact with skin tissue 40 plication No. 62-156508, and Stouffer US. Pat. No. in FIG. 3. Beneath the skin tissue is a layer of adipose, 4,785,817 each disclose a noninvasive method of mea 45 or fat, tissue 42, beneath which is muscle tissue 44. The suring fat thickness using ultrasonic waves. light shield 30 prevents the photo-transistors 20 from being exposed to ambient light. The ?rst IRED 16 SUMMARY OF THE INVENTION (FIG. 2) floods the adjacent volume of flesh with low intensity IR light, establishing a base illumination level The present invention provides apparatus and means using infrared radiation for quickly, accurately, and’ and thereby reducing the effect of ambient light on the noninvasively measuring the thickness of body fat. measurement. The second IRED 18 emits periodic pulses of high intensity IR light. The IR light from both In accordance with the present invention, a pair of IREDs is refracted by the adipose tissue; its intensity at infrared emitting diodes, one emitting a steady, low locations distant from the IREDs being indicative of the intensity light, and the other emitting periodic, high intensity pulses of light, are placed against the skin 55 thickness of the layer of fat 42. Each of the photo-transistors 20 provides a detection where the fat is to be measured. The low-intensity, signal representative of the intensity of IR light present steady illumination provides a base infrared level in the at its respective location. Referring again to FIG. 1, fat and reduces the effect of ambient light, while the high-intensity pulses refract through the fat, providing these detection signals are combined by the summing an indication of its thickness. An array of infrared-sensi 60 ampli?er 22, resulting in a composite signal. The A/D converter 24 converts the composite signal to digital form and supplies it to the display 26 which provides an indication of the thickness of the fat layer. from ambient light. The photo-transistors provide de It will be appreciated by those of ordinary skill in the tection signals proportional to the amount of infrared light detected, which are then summed and ampli?ed, 65 art that other types of infrared detectors, such as photo diodes, may be used in place of the photo-transistors forming a composite signal. The amplitude of this com described above. The larger surface area of the photo posite signal is indicative of the thickness of the layer of diodes may have the advantage of being less sensitive to fat and may be displayed and recorded. tive photo-transistors are placed against the skin at pre determined locations near the two diodes, yet shielded
1  5,014,713  METHOD AND APPARATUS FOR MEASURING THICKNESS OF FAT USING INFRARED LIGHT BACKGROUND OF THE INVENTION The pre...
3 5,014,713 4 A/D converter is held. The user may then remove the small irregularities immediately under the skin, such as caused by vascularization. meter from the skin and look at the LCD display which will continue to display the reading until capacitor C6 is A schematic diagram of an exemplary circuit em discharged. bodying the present invention is shown in FIG. 4. The terms and expressions which have been em Switch S1 allows the fat meter to be turned on or off by respectively connecting and disconnecting it from the ployed in the foregoing speci?cation are used therein as battery power supply B1. terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of In operation, the ?rst infrared emitting diode IREDl is biased on, with resistor R1 limiting its intensity. The state of the second infrared emitting diode IRED2 is controlled by a transistor Q1 which, in turn, is con trolled by device U1. Device U1 is a standard 555 timer con?gured as a 10 kHz oscillator with a SO-percent duty cycle. Resistor R11 limits the intensity of IRED2. The excluding equivalents of the features shown and de scribed or portions thereof, it being recognized the scope ofthe invention is de?ned and limited only by the claims which follow. What is claimed is: 1. A device for measuring the thickness of a layer of fat, comprising: IR light emitted by IREDI and IRED2 preferably has (a) a ?rst infrared emitter means for emitting infrared a wavelength of 950:20 nanometers (nm) and a band width of approximately 55 nm. The five photo~transistors Q4-Q8 detect IR light light at a steady intensity; (b) a second infrared emitter means for periodically having wavelengths within the range of 460 to 1060 nm, with maximum sensitivity at wavelengths of 850 nm, 20 (0) a plurality of infrared detector means for detect emitting pulses of infrared light; and produce respective detection signals having magni ing and sensing the magnitude of infrared light tudes corresponding to the intensities of IR light de tected. These detection signals are summed by device emitted by said ?rst and second emitter means after U2, which is a commercially available, dual operational through said layer of fat and producing respective detection signals in response thereto, said plurality transmission of said infrared light at least partially ampli?er TL082. Variable resistor R7 provides a means 25 for adjusting an offset value to compensate for the de tection signals caused by the steady, low-intensity IR light from IREDl. The resulting composite signal, pres ent on pin 7 of U2, is provided to pin 31 of device U3, a commercially available A/D converter. Resistors R9 30 and R8 form a voltage divider which determines a refer ence voltage for the A/D converter. Resistors R14 and R12 and capacitors C2-C5 have values as recom mended by the manufacturer of device U3 for 10 kHz input signals. The digital output of the A/D converter U3 is updated to correspond to the analog input at pin 31 when pin 1 of U3 is open-circuited. When pin 1 is forced “high,” then the digital output of U3 is held 35 of infrared detector means and said ?rst and second infrared emitter means being arrayed substantially in a single plane; (d) summing means for summing said detection sig nals and producing a composite signal correspond ing to a summation of said detection signals; and (e) output means responsive to said composite signal for producing an indication corresponding to said composite signal and indicative of the thickness of said layer of fat. 2. The device of claim 1 wherein said output means includes means for producing said indication in the form of a digital display. 3. The device of claim 1 wherein at least one of said constant at the value present when pin I became high. The digital output of the A/D converter U3 is pro plurality of infrared detector means is positioned equi distant from said ?rst and second infrared emitter vided to device LCDl, a liquid crystal display (LCD), which displays a digital representation of the digital means. 4. The device of claim 1 further comprising a momen output of the A/D converter. When the switch S1 is moved to the ON position, tary ON switch controllingly connected with said first capacitor C6 charges to the battery’s voltage less the 45 and second infrared emitter means so as to cause said voltage drop across diode CR1. When the switch is returned to the OFF position, transistors Q2 and Q3 conduct, and the voltage at the emitter of transistor Q2 first and second infrared emitter means to emit infrared light when said ON switch is activated, and means re is approximately two base-emitter voltage drops less than the voltage across C6. Capacitor C6, prevented from discharging through diode CR1, discharges in approximately ?fteen seconds through transistor Q3. During this time, transistor Q2 provides power to the balance of the circuitry. sponsive to said ON switch for providing said indica tion corresponding to said composite signal for a prede 50 termined time after said ON switch has been activated. 5. The device of claim 1 further including adjustable means for offsetting a portion of said composite signal to compensate for a portion of said composite signal resulting from sensing infrared light emitted by said ?rst Additionally, when switch S1 returns to the normal 55 infrared emitter means. 6. A method of detecting the thickness of a layer of OFF position, pin 1 of the A/D converter is connected fat beneath a skin surface, comprising the steps of: to the emitter of transistor Q2, causing the A/D con (a) directing infrared light into said layer of fat con verter to hold its digital output. In this manner, the meter may be used to measure the thickness of a fat layer where the user cannot see the meter. The meter is placed on the skin where the fat is tinuously at a ?rst intensity from a ?rst location on to be measured and the switch S1 is pressed ON mo nearby second location for predetermined periods mentarily. The photo-transistors Q4-Q8 measure the of time at a second intensity which is greater than intensity of the IR light, providing detection signals to the summing ampli?er U2. The summing ampli?er pro vides the composite signal to the A/D converter U3 which converts it to digital form. When the switch returns to the OFF position, the digital output of the said skin surface and simultaneously intermittently directing infrared light into said layer of fat from a 65 said ?rst intensity; (b) detecting respective intensities of said infrared light present at said skin surface at a plurality of respective predetermined distances from said loca tion;
3  5,014,713  4  A D converter is held. The user may then remove the  small irregularities immediately under the skin, suc...
5 5,014,713 the magnitude of said infrared light and producing respective detection signals in response thereto; (c) means for supporting said plurality of infrared respective values corresponding to said respective intensities; (d) summing said respective detection signals to pro duce a composite signal having a composite value; (c) adjusting said composite signal to compensate for portions of said detection signals which result from directing infrared light into said light of fat contin 6 (b) a plurality of infrared detector means for sensing (c) producing respective detection signals having detector means and said infrared emitter means arrayed substantially in a single plane with said infrared detector means arranged at predetermined distances from said infrared emitter means; ed 0 (d) summing means for summing said detection sig nals and producing a composite signal correspond ing to a summation of said detection signals; and uously at said ?rst intensity; and (e) output means responsive to said composite signal for producing an indication corresponding to said composite signal and indicative of the thickness of said layer of fat. (t) in response to said composite signal, providing an indication corresponding to said composite value and indicative of the thickness of said layer of fat. 8. The device of claim 7 wherein said infrared light 7. A device for measuring the thickness of a layer of fat in a human body, comprising: (a) infrared emitter means for emitting infrared light; has a wavelength within the range of 930 nanometers to 970 nanometers. * 25 35 45 55 65 i * i *
5  5,014,713  the magnitude of said infrared light and producing respective detection signals in response thereto   c  mea...
UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENTND. ; "5,014,713 DATED ; May 14, 1991 INVENTQMS); Alan Roper et al. It is certified that war appears in the above-identi?ed patent and that said Letters Patent is hereby corrected as shuwn below: Col. 5, line I 10, Change "said light of fat" to ——said layer of fat-—. Signed and Sealed this Twenty-second Day of September, 1992 Attest: DOUGLAS B. COMER Arresting O?icer Acting Commissioner of Patents and Trademarks
UNITED STATES PATENT AND TRADEMARK OFFICE  CERTIFICATE OF CORRECTION PATENTND.      5,014,713  DATED     May 14, 1991  INV...