Ultrasonic apparatus and method for measuring animal backfat

• US 6,012,332 A
• Filed: 12/29/1998
• Issued: 01/11/2000
• Est. Priority Date: 09/25/1996
• Status: Expired due to Fees

• Current Assignee: Perceptron Incorporated (Atlas Copco AB)
• Original Assignee: Perceptron Incorporated (Atlas Copco AB)
• Inventors: Schafer, Mark E.
• Primary Examiner(s): Noori, Max
• Application Number:
  US09/043,736
• Time in Patent Office: 378 Days
• Field of Search: 73/579, 73/584, 73/597, 73/615, 73/627, 73/629, 600/442, 600/449
• US Class Current: 73/579
• CPC Class Codes: A61B 2503/40 Animals
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces

Abstract

An ultrasonic measuring apparatus (FIG. 2) and method (FIG. 5) to accurately determine the depth of an overlaying backfat (14-20) on an animal (8) without incurring any damage to the animal. The apparatus employs a reverse time analysis approach in which a pulse generator (28) sends a preselected ultrasonic input signal by way of a piezoelectric transducer (16) through the outer skin (12) and successively through each one of the animal'"'"'s fat layer interfaces (15, 17, 20) to a preselected distance within the loin portion (22) of the animal. This reverse time approach then analyzes the resulting echo signal produced by the input signal sequentially in a direction from this loin portion toward the outer fat layers (14, 16, 18). The first strong signal within a specified range, which depends on the species, breed, age or weight of the animal to be measured, is taken as the bottom-most fat/loin transition. A microprocessor (44) is employed to measure and analyze the amplitude and contour of this signal in a direction toward the loin until it reaches a fixed point that is a prescribed percentage of the peak value of the amplitude of this signal, the magnitude of which depends on the type of animal under measurement. The value derived in this manner is an accurate measurement of the depth of overlaying backfat and is automatically displayed in digital form on a screen (46).

Claims

1. A system using a reverse time approach to accurately measure and indicate the thickness of backfat in an animal, comprising:

a pulse generator which generates an excitation signal;

a transducer responsive to said excitation signal to convert said excitation signal into an ultrasonic wave signal, to transmit said ultrasonic wave signal through the outer skin and backfat of said animal and then off of a backfat/loin interface of said animal, and to receive a responding ultrasonic echo signal;

a receiver which amplifies the responding ultrasonic echo signal reflected from the backfat/loin interface and converts said ultrasonic echo signal into an electrical echo signal;

a microprocessor operable to measure a peak of said electrical echo signal that is representative of the maximum amplitude of the responding ultrasound echo signal reflected from said fat/loin interface, said microprocessor being further operable to select a prescribed point on said electrical echo signal that is below said peak that represents an accurate measurement of the thickness of backfat in said animal; and

a display operably connected to said microprocessor which visually indicates the thickness of backfat in said animal.

2. A system as in claim 1, further comprising a pulse timing generator responsive to said microprocessor, said pulse timing generator generating timing signals for synchronizing the transmitting and receiving functions of said system.

3. A system as in claim 2, further comprising a log amplifier and envelope detector which amplifies said electrical echo signal in a logarithmic manner, a sampling rate clock responsive to a timing signal from said pulse timing generator, an analog to digital converter which converts said amplified electrical echo signal into a digital echo signal at a sample rate determined by said sampling rate clock, and a memory which stores said digital echo signal for processing by said microprocessor.

4. A system as in claim 1, wherein the animal is a member of the swine family and the prescribed point on said electrical echo signal that is below said peak is a point on said electrical echo signal having an amplitude that is approximately 30% less than the amplitude of said peak signal.

5. A system as in claim 1, wherein said ultrasonic wave signal is a single A-mode beam.

6. A system as in claim 1, wherein said transducer is a piezoelectric transducer and oil is used as a coupling fluid to transmit said ultrasonic wave signal through the outer skin of said animal and to receive the responding ultrasonic echo signal from the outer skin of said animal.

7. A system as in claim 6, wherein the piezoelectric transducer is placed on a loin of the animal in close proximity to the backfat/loin interface.

8. A system as in claim 1, wherein, when the animal is a hog weighing between 200 and 280 pounds, a threshold for a maximum backfat thickness of said animal between the skin and fat/loin interface is set to 2.5 inches, whereby a last peak in said electrical echo signal before said threshold is processed by said microprocessor to determine the thickness of the backfat of the animal.

9. A reverse time system for accurately measuring the depth of backfat in an animal, comprising:

means for sending an ultrasonic input signal of a predetermined time duration through the skin of said animal so as to extend through its backfat into a loin portion thereof and for receiving an echo signal from a backfat/loin interface of the animal regardless of the species, breed, age, weight or number of fat layers the animal possesses;

means for sensing the amplitude of the peak of the echo signal generated by the backfat/loin interface, for determining a point on said echo signal having an amplitude which is a predetermined percentage of the amplitude of the peak, said point being related to at least one of the species, breed, age, weight, or number of fat layers of the animal, and for converting a waveform representing a time value of said point on said echo signal into a measurement of the depth of backfat possessed by the animal; and

means for displaying said backfat depth.

10. A system as in claim 9, wherein the animal is a member of the swine family and said point on said echo signal has an amplitude that is approximately 30% less than the amplitude of said peak signal and is adjustable for different animals in accordance with experimental research regarding the species, breed, age, weight or number of fat layers of the different animals.

11. A method of accurately measuring the depth of the backfat in an animal, comprising the steps of:

transmitting an ultrasonic input signal through the backfat and loin interface of the animal;

sampling a responding echo waveform from the backfat/loin interface of the animal and storing the sampled echo waveform in a memory;

reading the sampled echo waveform in reverse time order from the memory for echo samples from the loin toward echo samples from the fat/loin interface;

locating a peak amplitude in the sampled echo waveform generated by the fat/loin interface;

selecting a prescribed percentage of the amplitude of the peak that is characteristic of the type of animal under measurement;

reading the sampled echo waveform in a forward time order from said peak until a point is found having an amplitude that is approximately said prescribed percentage of the amplitude of the peak; and

determining the depth of the backfat in the animal based on the response time corresponding to the point in said echo waveform having an amplitude that is approximately said prescribed percentage of the amplitude of the peak.