NZ252213A - Meat quality optical measurement probe - Google Patents

Description

252213 New Zealand No. 252213 International No. PCT/FR93/00496 Priority Dai3{s): S?.|s;.!..'ri.^r.

Complete Specification Fiiad: .3 Class: Publication Date: 1L.1...P.EP.J9.95 P.O. Journal No: NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Apparatus for measuring the quality of meat Name, address and nationality of applicant(s) as in international application form: SYDEL SA, of Rue du Gaillec, Z.I. de Keryado, 56100 Lorient, France A Gcupora^- \. I Pi 2522 1 3 i f\ MEAT QUALITY MEASURING DEVICE FIELD OF THE INVENTION The present invention concerns a device for measuring the quality of meat, in particular for measuring the muscle content of a carcass.

BACKGROUND OF THE INVENTION Devices of this type, such as those described in the French patent no. 2 334 088 filed by J.B. HENNESSY in 1976, comprise three main elements : a probe, a depth reference piston and a measuring casing. The probe is a lancet comprising a point and a rod equipped with a measuring head placed in a window near the point. This measuring head comprises a phototransmitter and a photoreceiver separated by an opaque partition. The light emitted by the transmitter is reflected and diffused through the medium into which the probe is driven and the extent of this reflection varies according to the optical characteristics of the traversed medium. A sudden reduction of the signal delivered by the receiver indicates the passage of fat in the muscle according to the different reflection factors of these two constituents of the carcass.

The depth reference piston is integral with two sliding parallel supports rods and is pushed forward by a helical spring engaged on the rod of the probe. One of these support rods drives in rotation a dial indicating the driving-in depth of the probe, the drive member being adapted to be thrown out of gear and jammed when the the measurement signal shows a sudden variation characterizing a change of medium.

One drawback inherent in these measuring devices is that they are not sufficiently accurate and their resolution is 22 1 3 relatively mediocre. In fact, owing to the size of the optoelectronic components used and their relative position, the beams emitted and received are parallel and relatively distanced from one another. During a change of medium, the 5 signal produced does not vary abruptly, but progressively over a range of several millimetres.

One solution to resolve this drawback was put forward by processing the measuring signal, as described in the European patent EP-A-0 028 509 , also filed by J.B. HENNESSY. From the 10 maximum and minimum values of the signal produced by the photoreceiver, which respectively correspond to the light intensities reflected by the fat and lean meat, it has been possible to deduce an intermediate signal level taken as a reference. For changes of fat/lean medium or vice versa, the 15 depth indications are road when the photoreceiver produces a signal equal to this reference. This modification of the initial device has made it possible to improve the accuracy of the measurement of thickness of fat and muscle, but the resolution of these measurements remains as poor as obtained 20 previously. In fact, owing to the fact that in the probes described in these patents, the illuminated zone has a relatively large range and it is impossible to detect the passage of thin membranes, such as aponeurosis, which would definitely be useful for measuring the percentage of muscle in 2^ pig carcasses since they surround the rib eye.

Added to this drawback relating to the measurement of the optical factors of the constituents of carcasses is another concerning the uncertainty of the driving depth of the lancet in the carcass when a change of medium occurs. Owing to the 30 rapid movements the device undergoes when a measurement is being effected and the inertia of its mobile elements, the instantaneous position of. the depth reference piston pressed with a variable support force by a simple spring on the surface 2522 1 J of the carcass is not known accurately at the time when the sought-after change takes place. This results in a significant error of depth and therfore a similar type of error as regards the percentages of fat and/or lean meat.

SUMMARY OF THE INVENTION The main object of the invention is to provide a device to measure the quality of meat, the accuracy and resolution of the 10 two measurements concerned (changes of medium and the driving depth of the probe) being significantly improved.

A further object of the invention is to provide a device to measure the quality of meat and able to process the rough measurements obtained so as to produce an amount representative 15 of a specific parameter of this quality, such as the percentage of muscle.

According to one first characteristic of the invention, in a device for measuring the quality of meat of the type including : - a lancet-shaped probe adapted to penetrate into the carcass and provided with an optical measuring head ; - a depth reference support associated with the probe and to be applied to the carcass to be processed ; - a device to continuously measure the distance separating the measuring head of said support ; - a measuring phototransmitter and photoreceiver constituting the measuring head both being disposed with respect to each other so as to produce an analog measuring signal representative of the luminous reflectivity of the surrounding medium ; is characterized in that ; - the measuring phototransmitter and photoreceiver are disposed at the bottom of fine optical channels made in an optical 2522 1 3 4 support, said channels being orientated so that the axes of these channels cross at a convergence point situated close by immediately outside the surface of the probe.

In addition, so as to be able to control the intensity of 5 light generated by the phototransmitter, a reference photoreceiver is provided and placed in a third channel opening into the channel traversed by the light emitted by the phototransmitter.

By means of these two dispositions, the accuracy, 10 resolution and reliability of an optical probe for measuring the quality of meat have significantly improved.

In one embodiment, the device is a gun to which the probe is secured. The support is a piston which longitudinally translation-moves with respect to the probe and borne, for 15 example, by two sliding support rods.

According to a second characteristic of the invention, the support rods of the depth reference piston drive in rotation the shaft of a torque motor and the intensity of the direct current feeding this motor is automatically controlled to equal 20 a set-point value.

By means of this disposition, the relatively fast movements the operator makes any device undergo during a measurement, despite the inertia of masses moving in the device, do not result in causing undesirable variations of the 2^ supporting force of the reference piston on the surface of the carcass. These variations do in fact lead to unequal drivings of the piston in the carcass and thus an error as regards the depth measured at a given time.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics and advantages of the invention shall become more apparent on a reading of the remainder of the 252213 following description of an embodiment, given by way of non-restrictive example and with reference to the accompanying drawings on which : - Figure 1 is a diagrammatic top view of a measuring device according to the invention ; - Figure 2 is an enlarged view of a longitudinal section of the probe section in which the optoelectronic measuring components are disposed ; - Figure 3 is a cross section of said section of the device ; - Figure 4 is a simplified longitudinal section of the device; - Figure 5 is a cross section of the device ; - Figure 6 is a block diagram of the electronic circuits of the data acquisition card of the device ; - Figure 7 is the block diagram of the electronic circuits of the data management card of the device ; - Figure 8 is the block diagram of the electronic circuits for automatically controlling the support force of the reference piston, and - Figure 9 is a graphic representation of two measurements respectively obtained with the aid of a known device and the improved device of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS On figure 4, a device for measuring the quality of meat is shown in its normal form, namely that of a pricking gun provided with a grasping crosshead 66.

According to figure 1, this device includes an elongated casing 10 and a measuring probe 12. This probe 12 is formed of a lancet comprising a sharp point 14 and a rigid hollow rod 16 fixed to the casing 10, a measuring head 18 being disposed 25221 3 6 close to the point 14. Without, touching it, the rod 16 traverses a support piston 20 mounted at the end of two rigid parallel and longitudinally mobile support rods 22-24 inside the casing 10.

The measuring head 18 of the probe 12 is housed in a section 26 of the hollow rod 16. According to figures 2 and 3 which respectively represent longitudinal and side sections of this section 26, the measuring head 18 includes an opaque plastic support 28 having the general shape of a parallelpiped 10 with one outer face 30 shaped so as to extend the cylindrical surface of the section 26. The support 28 comprises between its bottom and its outer face 30 two passages 32-34 whose respective axes converge immediately outside the outer face 30. The passages 32-34 have a widened diameter in their portions 15 32a-34a close to the bottom of the support 28 and a narrow diameter in their portions 32b-34b opening onto the outer face 30 of the support 28. Respectively disposed in the wide portions 34a-32a are a phototransmitter 36 constituted by a red ray and/or an infrared ray transmitter, and a photoreceiver 38 2o constituted by a photodiode or phototransistor sensitive to these rays. The narrow portions 34b-32b of the passages 34-32 constitute fine guidance channels for guiding the light emitted and received, said channels opening side by side but without rejoining in the outer face 30 of the support 28. In this way 25 dur ing functioning, there is no direct transmission of light around their border line F.

In the measuring head 18, the two passages 32-34 are slanted longitudinally by a given angle close to 12°. The value of this angle has been selected so as to limit the 30 ovalization of the orifices of the fine channels 32b-34B and secondly to ensure that the point of convergence of the axes of these channels remains sufficiently close to the wall 30 of the measuring head. In practice, the channels 32b-34b preferably 2522 1 J have a diameter of 0.5 mm, the distance between the point of convergence of their axes and the wall of the probe then being about 1 mm.

The phototransmitting diodes are known to be generally 5 less stable as regards time and temperature. Accordingly, the support 28 comprises a longitudinal passage 40 with two diameters 40a-40b, that is wide and narrow respectively, said passage opening into the transmission channel 34b. Mounted in the wide portion of the passage 40 is a reference photoreceiver -^0 42 identical to the measuring photoreceiver 38 and intended to regulate the intensity of the light emitted by the phototransmitter 36. The regulation circuit used is diagramatically shown on figure 6.

So as to facilitate placing and ensure supporting of the 2^ electronic components, namely the transmitter 36 and the receivers 38-42, the wide portions 32a, 34a, 40a of the passages 32-34-40 comprise lateral apertures 32c, 34c, 40c. Moreover, two longitudinal grooves 44-46 are made in the bottom of the support 28 to allow for the passage of linking wires 20 towards the casing 10 through the hollow rod 16 of the probe 12 .

The measuring head 18 is installed in a housing 48 provided in the median portion of the section 26 of the rod 16 of the probe 12. The end 52 of the section 26 is a full 25 threaded joining piece screwed into the point 14 and the end 54 is a hollow joining piece adjusted and glued in the rod 16 of the probe. The housing 48 opens onto the outside via an oblong longitudinal window through which the support 28 equipped with the components 36-38-42 constituting the measuring head 18 is 30 introduced. After insertion, the measuring head 18 is compound-filled with a resin 56. As for the channels 32-34-40, they have previously been sealed with a transparent resin once the components 36-38-42 have been placed. 6 252213 8 According to figure 4, the rigid hollow rod 16 of the probe 12 is relatively long and its rear portion is inside the • casing 10 and embedded in two support blocks 60-62 constituting the edges of a base 64 of the casing 10. Fixed by screws to 5 this base 64 are the crosshead 66 of the pricking gun constituted by the device (screws 65-67), a front face (screw 69) and a covering cap 58 of the casing 10. Mounted in the cross 66 is an acoustic device 63 constituting a sound alarm signalling a defect of the use of the device. The covering cap 10 58 is firstly squeezed between the base 64 and the crosshead 66, and secondly fixed by screws 59 to the front face 68. Mounted in the upper portion of the front face 68 is a multipin socket 79 allowing for connection of the device to a central computer (not shown) ensuring more complete exploitation of the 1-5 measurements provided by the device.

According to figure 5, the support block 60, and behind the front face 68, comprises three parallel passages : one central passage 70 traversed by the fixed rod 16 of the probe 12, and lateral passages 72-74 traversed by the two parallel 2o sliding support rods 22-24. According to figure 4, the front ends of these rods 22-24 are embedded in a block 21 secured to the piston 20 (a rectangular plate with rounded corners) by screws (not shown).

According to figure 5, the rear ends of the rods 22-24 25 inside the casing 10 are embedded in a carriage 76 mounted sliding on the rod 16 of the probe 12. On figure 4, this carriage 76 is diagrammatically shown twice at 76a and 76b so as to show the two extreme positions it is able to occupy. The carriage 76 is fixed to a synchronous belt 78 stretched between 30 two pulleys 80-82 respectively mounted rotating in bearings 84 installed on flanges 86 or 88 integral with support blocks 60 or 62. The shaft 81 of the pulley 80 comprises at one end a gear 90 gearing with a smaller gear 92 integral with the output 252213 9 shaft of a torque motor 94 mounted on a bracket 96 extending one of the flanges 86.

Mounted on one end of the shaft 81 is the etched disk 98 of an optical rotation sensor 100 adapted to deliver a relatively high number (1440, for example) of pulses to be counted up or down per revolution in either direction of the shaft 81 of the pulley 80. In this way, a new pulse is produced for each movement increment of the belt 78 (an increment is 0.025 mm, for example) According to figure 4, mounted below the belt 78 are two printed circuit cards, namely the data acquisition card 97 and the card 99 for managing this data. According to figure 6, which represents the general block diagram of these electronic circuits, the phototransmitter 36 is fed by an amplifier 37 which input receives the output signal of an amplitude comparator 41. The two inputs of this comparator 41 are respectively connected to the output of an amplifier 43 whose input is connected to the reference photoreceiver 42, and to that of a reference potentiometer 45. The measuring photoreceiver 38 is connected to the input of an amplifier 39 whose output signal is applied to a continuous functioning type analog/digital converter 101.

For its part, the optical sensor 100 driven by the shaft 81 of the pulley 80 is connected to a reversible counter 102. The output stages of the analog/digital converter 101 and of the reversible counter 102 are connected to the input bus of a first microprocessor 103 associated with a first temporary memory 104 operating under the control of operating and application software contained in a first permanent memory 105.

According to figure 7, which represents the block diagram of the electronic cards of the data management card 99, the output bus of the first microprocessor 103 is connected to the input bus of a second micr oprocesor 106 associated with a 22 1 3 second temporary memory 107 and with a second permanent memory 108 containing the application and operating software of the second microprocessor 106. Also connected to the input bus of the second microprocessor 106 are push-buttons 108 disposed at the upper portion of the crosshead 66 (see 109a-109b on figure 4). Connected to the output bus of the microprocessor 106 are firstly a liquid display device 110 disposed under a transparent window fitted in the covering cap 58 of the casing 10 (see figure 4), and secondly pins of the multipin socket 79 secured to the front face 68.

According to figure 8, the terminals 111-112 of the d.c. torque motor are respectively connected to the output of a direct current (I) generator 114 and to a low value resistor 116 connected to the ground. The terminals 111-112 of the motor 94 are connected to a measuring bridge 118 comprising an adjustment potentiometer 119 adapted to deliver a nil value voltage V when the motor 94 is blocked, and with positive or negative values proportional to the back-electromotive forces developed by the motor when the latter, driven by the belt 7 8 during the penetration phase of the probe 12 into the carcass, rotates in a first direction, or during the phase for withdrawal of the probe 12 from the carcasss, rotates in the other direction. In this second case, the belt 78, the carriage 76 and the piston 20 do not undergo any external stresses and the motor 94 is free which, under the action of the current I, rotates until the piston 20 is at the front stop. The terminal 112, common to the motor 94 and the resistor 116, is connected to one of the two inputs of a circuit 120 for automatically controlling the intensity of the current I delivered by the generator 114, the other input of this circuit 120 being connected to the output of a circuit 122 for limiting the set-points of the current I and includes a potentiometric divider 123. The circuit 122 comprises two types of inputs : one analog 22 1 3 11 input 124 and one logic input 126 adapted to control the divider 123. The signal applied to the analog input 124 is a continuous signal which is furnished by a receiving summing stage, a reference variable signal for the current I delivered by a potentiometer 130, and secondly a correction signal delivered by a circuit 132. This circuit 132 is a derivative stage to which the voltage V is applied representative of the rotational speed of the motor 94 provided by the measuring bridge 118. The circuit 132 comprises a potentiometer 133 and delivers an analog signal A representative of the angular acceleration of the motor 94, the meter constant of the signal A being fixed by the potentiometer 133.

The signal V furnished by the measuring bridge 118 is in addition applied to the input of a double comparator stage 134 adapted 'to deliver on its two outputs two logic signals Si and S2 respectively representative of the front and rear directions of the motor 94 when the absolute value of the signal V is greater than a threshold Vo. The signal Sl=l appears during the phase for driving of the probe 12 into a carcass, and the signal S2=l during tho probe withdrawal phase. The s imul taneousness of the conditions 0 of the signals SI and S2 means that the motor 94 is either blocked or rotating at an extremely slow speed in either direction. These signals SI and S2 are applied to a logic circuit 136 for controlling the set points receiving moreover two logic signals B1 and B2 representative of the front and rear stops of the carriage 76. The signals B1-B2 are respectively provided by two optoelectronic detectors 138-140 respectively mounted on the front and rear support blocks 60-62 of the rod 16 of the probe 12. These detectors 138-140 can be hidden by a relatively wide flag 77 fixed via its middle to the carriage 76 sliding on the rod 16. In this way, the simultaneousness of the conditions 0 of the signals B1-B2 means that the flag does not hide any of 252213 12 the stop detectors 138-140. As regards the condition 1 of either of the signals B1-B2, it expresses the fact that the flag 77 hides one of these stop detectors. Depending on the values of the logic signals S1-S2, this may mean that either the carriage 76 comes nearer to or draws away from its front (the support 60) or rear (the support 62) physical stop if one of the signals S1-S2 is equal to 1, or it is in contact with one of these physical stops if the two signals S1-S2 are both in the condition O. The logic control circuit 136 delivers two logic signals C and F respectively applied to the logic input 126 of the circuit 122 for limiting the set-point of the current I and to the control logic input 142 of a short-circuit switch 146 disposed between the terminals 111-112 of the torque motor 94. The potentiometric divider 123 controlled by the signal C introduces a relatively high reduction factor (10, for example). The logic signals C and F worked out by the control logic stage 136 satisfy the following equations : C = SI + B1 and F = S1.B2 + S2.B1.

Also placed between the terminals 111-112 of the motor 94 is an electromechanical relay 148 adapted to be open when the device is functioning and closed when not. The functioning of the switch 146 and that of the relay 148 both have the effect of braking the piston 20 by causing a short-circuit at the terminals of the motor 94.

The pricking gun shown on figure 4 is used by a human operator or by a robot. In these two cases, the device undergoes front and then rear translation movements and the lancet constituted by the probe 12 is driven into the carcass to be measured and then withdrawn, whereas the depth reference piston 20 and the rods 22-24 bearing it are pushed back inside the casing 10 and are then freed. The support rods 22-24 of the piston 20 drive the carriage 76 integral with the belt 78 which in turn, by means of the pulley 80 and the pinions 90-92, makes 2522 1 3 13 the torque motor 94 rotate. The etphed disk 98 of the optical rotation sensor 100 driven by the shaft 81 of the pulley 80 delivers pulses to be counted up or down representative of the movements of the belt 78. The reversible counter 102 receives 5 the pulses produced by the sensor 100 having previously been adjusted to a value corresponding to the minimal distance between the measuring head 18 and the front face of the piston 20 (in this case, the carriage 76 is in contact with the support block 60), the number present at any time in this 10 reversible counter 102 being representative of the amplitude of the displacement of the piston 20 and thus of the penetration depth of the measuring head 18 into the carcass concerned.

To ensure that this penetration depth measurement of the meauring head 18 into this carcass is correct, it is essential 15 that the driving of the front face of the piston 20 into the carcass is known accurately and be repeated from one measurement to another. Automatically controlling to a set-point value of the support force of the piston 20 on a carcass is ensured by the device described on figure 8. 20 According to figure 8, the current I provided by the generator 114 which feeds the torque motor 94 is controlled so as to create at the terminals of the resistor 116 a voltage equal to the set-point value delivered by the reference value limitation stage 120. In the absence of any logic signal C 25 control-applied to the potentiometric divider 123, the set-point value present at 124 upstream of the stage 122 is found downstream. This set-point value includes two terms, namely concerning the main function furnished by the potentiometer 130 and the other for correction proportional to the angular 30 acceleration the motor 9 4 undergoes and thus to the force applied to the reference piston 20 by the operator or robot. The weighting factor of this correction signal is determined empirically according to the characteristics of the environment 22 1 3 14 (motor 94, measuring bridge 118, ,differential stage 132 and voltage for feeding the potentiometer 130). In practice, once the device has been finally produced, for a standard adjustment of the potentiometer 130, the gain of the amplifier which the 5 stage 132 comprises is adjusted via action on the potentiometer 133 so that the variations, due to the inertia of the moving masses of the support forces of the piston 20 on a carcass are compensated, these forces resulting from the relatively fast movements the operator makes the entire device undergo. These 10 support force variations are read on a force sensor (spring/potentiometer) disposed for adjustment on the front face of the piston 20. In this way, the standard support force of the piston 20 on the carcasses is firstly determined by the maximum value of the set-point current applied to the torque 15 motor 94 when the piston 20, previously placed in a rear position, comes out again with the standard speed the operator shall allow it to have during the phase for withdrawal of the probe 12 from the carcass to be measured. This maximum set-point value is fixed by adjusting the potentiometer 130. The 20 support force of the piston 20 of each device leaving production may accordingly be easily adusted to a standard value, irrespective of the rubbings in the passages 72-74 of the rods 22-24 bearing this piston. In addition, by means of the set-point correction signal proportional to the angular 2jj acceleration of the motor 94, the inertia forces due to the inevitable irregular movements of the device, after the potentiometer has been adjusted, are automatically compensated and the support force of the piston 20 on the carcass is kept to its standard value. jq The logic signal C = Sl+Bl worked out by the stage 136 is control-applied to the input 126 of the potentiometric divider 133. When Bl = l, the piston 20 is at the front stop, which is the case from the moment when a pricking operation ends until 22 1 3 the time another pricking operation starts. In this case, the aim of the reduction to its minimal value of the set-point value of the current I feeding the torque motor 94 is to relieve the battery feeding the device. When SI = 1, the piston 5 20 leaves its front stop and the probe 12 is driven into the carcass to be measured. In this case, the aim of the reduction of the current I is to reduce the force the operator requires during the phase for penetration of the probe 12 into the carcass. As a result of the foregoing, the set-point value of 10 the current I is maximum from the end of the phase for penetration of the probe into the carcass until the end of the phase for withdrawal of this probe. In this way, the piston 20 is applied to the carcass with a standard value support force throughout the carcass measuring phase.

The logic signal F = S1.B2 + S2.B1 worked out by the stage 136 is control-applied to the short-circuit switch 146. When S1.B2 = 1, the relatively wide flag 77 integral with the carriage 76 driven by the piston 20 starts to hide the photoelectric detector 140 of the rear stop of the piston 20. 2g At this moment, the phase for penetration of the probe 12 into the carcass is nearing its end, and, so as to avoid an impact of the carriage 76 on the mechanical stop constituted by the support block 62, the motor 94 is short-circuited by the switch 146 controlled by the logic signal F, which has the effect of 2j5 considerably braking the rotation of the motor 94 and the backward movement of the carriage 76. As soon as the speed of rotation of the motor 94 falls below the threshold value Vo, the signal SI = 0 and F - 0, which has the effect of freeing the motor 94 so as to enable it to apply to the piston 20 a 30 standard support force once the phase for withdrawal of the probe has begun.

When the flag 77 starts to hide the photoelectric detector 138 from the front stop of the piston 20, the probe withdrawal 25221 J 16 phase is nearly over and F = S2.B1 ?= 1, which has the effect of short-circuiting and braking the motor 94 until another pricking operation starts. In addition, during this interval between two successive pricking operations, the set-point value of the current I circulating in the switch 146 short-circuiting the motor 94 is minimal.

Figure 9 shows the results of two measurements respectively carried out on a given pig carcass with the aid of an improved device according to the invention (graph A) and a known type of device (graph B). The driving in depths of the probe are indicated in abscissae and the values of the luminous reflectivity measurements of the layers traversed are indicated in ordinates. The probe is successively driven into two particular points of the carcass situated between two pairs of ribs until they come out again in the thoracic vacuum. The measurements are made when the probe is being withdrawn and the signals are recorded from the left towards the right on the graphs. First of all, each of the signals is minimal and shows the thoracic vacuum. Then their growth from the 7.6 cm rib expresses the passage in a greasy or cartilaginous zone. If the graphs A and B are compared with the layer extending from the ribs 7.6 to 6.4 cm, it can be seen firstly that the number of measurements carried out in the first case is much larger than that of the second. The resolution of the depth measurements of the improved device of the invention is far greater than that of known type of devices. Moreover, if two successive measurements carried out on a given site are compared with the device of the invention and then with a known type of device, this reveals in the first case excellent repeatibi1ity of the results and in the second a significant dispersion. In the first case, this is due to the fact that the piston 20 is applied to the carcass with a constant support force during the two operations, and in the second case with a support force 2522 1 3 17 that cannot be constant, regardless of the attention paid by the operator. With a device conforming to the invention, the depth measurements have particularly exceptional resolution, accuracy and reliability.

Then, it can be seen that a particular measurement may assume extremely high amplitude with respect to that of the preceding measurement or the one immediately following, which is not the case with the measurements of graph B. This is due to the extremely high resolution of the measurements of the luminous reflectivity provided by the measuring head of the probe of the invention : fine optical channels 32b-34b converge immediately close to the wall of the head 18.

This improved double resolution of the measurements furnished by the device of the invention, as regards the layer defined by the ribs 7.6 = 6.4 cm, is able to mark, in addition to the peak PI common to the two graphs (it characterizes a cartilege), a particularly large second peak P2 which does not appear on graph B. This peak P2 corresponds to the aponeurosis, a membrane with a thickness of of several millimters, which surrounds the rib eye. It is from the position of the peak P2 that the muscle starts which corresponds to the passage of the 6.6 rib to the 1.6 rib. The level of the measuring signal in this passage is stable, except at two particular points marked by the peaks P3-P4 which indicate the presence in the mass of the muscle layers of relatively fatty tissues. The known type of probe has been unable to detect these thin layers owing to its insufficient resolution. From the 1.6 cm rib, the passage from the lean meat to the surface grease on graph A appears much clearer than on graph B.

Generally speaking, the double resolution (measurement of the lumnious reflectibility of the layers traversed and measurement of the depth of these layers) of the improved device of the invention is about ten times greater than the 252213 18 double resolution of known type of devices. In these circumstances, the device of the invention affords new possibilities for exploiting the data furnished. The accuracy of this data in fact makes it possible to use the device of the 5 invention for measuring the quality of meat and in particular for measurements on meat other than pork, such as ovine or bovine meat (measurement of marbled meat).

A complete operation for measuring the percentage of muscle of a half pig carcass includes two successive prickings. 10 The two sites of these prickings are required to be effected by the official administrative services concerned. The first site is situated betwen the third and fourth lumbar vertebra eight centimeters from the fissure of a half-carcass. The second site is situated between the third and fourth sub-15 final rib six centimeters from the fissure.

As a pricking is gradually being made, the microprocessor 103 of the data acquisition stage operating under the control of the first application software successively carries out the following operations : (1) periodically calling (at a frequency of 10 KHz, for example) the content of the output stages of the analog/digital converter 101 and of the reversible counter 102 during the probe 12 withdrawal phase ; (2) combining the two numbers present at this moment in 25 the output stages so as to form two fields associated with measuring bits ; (3) apply these bit fields to the temporary memory 104 so as to progressively constitute a raw data frame corresponding to the simultaneous luminous reflectivity and probe depth measurements carried out during a pricking operation ; (4) transfer this raw data frame to the microprocessor 106 of the data management stage at the end of each pricking operat i on.

The microprocessor 106 operating under the control of the second application software is adapted to carry out the following operations : (1) in response to the instructions of the operator, pushbuttons 109 are used to display on the display device 110 the menu of the various possible functions of the data management stage ; (2) in response to the instructions of the operator, update the number of the carcass to be treated and store this number in the temporary memory 107 ; (3) store in the temporary memory 107 the raw data frame transferred by the microprocessor 103 of the the data acquisition stage ; (4) analyse the stored raw data so as to detect there the characteristic points to be retained for calculation of the value of the meat quality parameter concerned ; (5) store the depths of these characteristic points in the temporary memory 107 ; (6) control the functioning of an alarm 63 should the characteristic points in question be unable to be detected in the frame of the raw data analysed, said alarm informing the operator that the pricking operation carried out is incorrect and needs to be restarted ; (7) combine the depths of the characteristic points detected in two frames of raw data read on a given carcass according to an equation conforming to the rules applicable to the sought-after quality parameter relating to the type of carcasses measured so as to produce a digital value representative of this parameter ; (8) store this digital value calculated on the display device 110 ; (9) display the last digital value calculated on the display device 110 ; 252213 (10) increment by one qnit the carcass number corresponding to the next raw data frame to receive the data acquisition stage ; (11) in response to an instruction of the operator, transfer to a central computer the contents of the temporary memory 107.

In practice, the temporary mepory 107 of the data management stage could contain a hundred raw data frames corresponding to about fifty carcasses measured and the depths of the characteristic points detected in these frames and the digital values of the quality parameter calculated on the basis of these points. Accordingly, the operator could proceed with measuring about fifty carcasses before transferring to a central computer all the data collected and the values calculated by the measuring device of the invention.

When the measuring device of the invention is to be used for carcasses other than pig carcasses (beef or mutton in particular), the functions of the data acquisition stage shall be virtually unchanged, even if the procedure followed by the operator during a pricking is significantly different to the one used for pig carcasses. On the other hand, the operations (4) and (7) carried out by the microprocessor 106 of the data management stage shall of course differ from those provided for a pig carcass. For the operation (4), the characteristic points to be retained shall be specific points of the type of carcasses to be treated. Similarly for the operation (7), the equation to be used shall concern these carcasses.

By way of variant, it shall be observed that the measuring device of the invention may only comprise one data acquisition stage and that, if the device is constantly connected to a central computer, this stage could only carry out the operations (1) and (2) referred to above, the operations (3) and (4) described being replaced by the following operation : 2 2 1- 21 - apply these two fields associated with a temporary memory to a central computer so as to progressively constitute a raw data frame corresponding to the simultaneous luminous reflectivity and probe depth measurements carried out during a 5 pricking operation.

In this case, the operations (3) and (4) initially effected by the data acquisition stage and all the operations carried out by the data management stage shall be acted upon by the central computer.

This description is clearly not restrictive. In particular, although it takes into account a mounted fixed probe on a casing and associated with a mobile reference depth support, it goes without saying that this combination may be inverted, namely a mobile probe associated with a fixed support.

Similarly, as regards the luminous means (transmission, detection and adjustment), they have been shown as existing in the detection end of the probe, but they could also clearly be located at a distant location, which would require merely 2o extending inwardly the channels for transferring the light as far as this distant location.

Claims (8)

25221 22 WHAT IS CLAIMED IS : 1. Device for measuring a meat quality parameter of a carcass, said device including : 5 - a lancet-shaped probe adapted to penetrate into the carcass and provided with an optical measuring head; - a reference depth support associated with the probe and intended to be applied to a carcass to be processed ; a device to continuously measure the distance 10 separating the measuring head from said support; - a measuring phototransmitter and measuring photoreceiver both constituting the measuring head and disposed with respect to each other so as to produce an analog signal representative of the luminous reflectivity of the surrounding 15 medium ; the measuring phototransmitter and measuring photoreceiver are disposed at the bottom of fine optical channels made in an opaque support, said channels being orientated so that their axes cross at a 20 convergence point situated immediately outside the surface of the probe. 2. Measuring device according to claim 1, wherein an emission regulation photoreceiver is disposed at the bottom of an optical channel opening into the fine 25 channel of the phototransmitter. 3. Measuring device according to claim 1 or 2, wherein the optical transmission and receiving channels are symmetrically slanted by an angle of about 12° with respect to a transverse plane of a rod of the probe. 30 4. Measuring device according to any one of the preceding claims, wherein the optical channels have a diameter of about 0.5mm and are sealed with a transparent resin. 5. Device for measuring a meat quality parameter of a 252213 23 carcass according to claim 1 or claim 2 10 including means to apply the support to the carcass to 15 be processed, which means include a torque motor automatically controlled so as to deliver a torgue keeping to a set-point value the force applying the support to the carcass. 6. Measuring device according to claim 5 in which the probe is a rigid hollow rod mounted 20 fixed in a casing, and the support is a mobile piston integral with two support rods adapted to slide into the casing and drive the device for measuring the driving- in depth of the measuring head, wherein the rod of the probe in its portion inside the casing is embedded in 25 two support blocks respectively fixed to the ends of a base of said casing, the support rods of the piston are mounted sliding in a . front support and embedded in a carriage mounted sliding on said portion of the rod inside the casing, said carriage is integral 30 with a synchronous belt stretched between two pulleys respectively mounted rotating in bearings borne by said support blocks , the shaft of one pulley rhtion angular rotation comprising at one —a. high—rj N.Z. PATENT OFF 21 NOV 1995 received 252213 24 optical sensor delivering pulses to be counted up or down according to the direction of rotation and, at the other end, a first gear gearing with a second gear fixed to the shaft of the torque motor. 5 7. Measuring device according to claim 5 or claim 6 in which the probe is a rigid hollow rod mounted fixed in a casing, and the support is a mobile piston integral with two support rods adapted to slide into the casing and drive the device for measuring the driving- 10 in depth of the measuring head/ wherein means are provided to produce an analog signal representative of the rotation speed of the motor , wherein a derivative stage provided with a gain adjustment potentiometer is adapted to deliver an analog signal representative of the angular acceleration of the motor and wherein a summing stage is adapted to add a reference signal furnished by a potentiometer and said acceleration signal, the adjustment of the gain potentiometer being selected so that the variations of the support force of the piston are 20 compensated on a carcass due to the inertia of the mobile masses of the device during a measuring operation. 8. Measuring device according to claim 6 or claim 7, wherein a rotational speed signal of the motor is applied to the input of a stage for detecting the direction of 25 rotation, said stage being adapted to deliver two logic signals S1-S2 representative of these directions when the absolute value of this speed is greater than a given threshold ; - a flag borne by a carriage integral with the support rods of the piston is adapted 30 to hide two optical stop detectors respectively mounted on support blocks of the rod of the probe and adapted to deliver two logic signals B1-B2;. - a logic circuit adapted to receive 252213 10 15 25 S2 and B1-B2 and combine them so as to produce two logic signals C = Sl+Bl and F = S1.B2 + S2.B1; said logic signal C being control-applied to a potentiometric divider disposed in series in a link established between a sunming stage and a current automatic control stage. - said logic signal F being control-applied for closing a short-circuit switch disposed between the terminals of the motor. 9. Measuring device according to claim 2 or any one of claims 3 to 6, when dependent upon claim 2, which comprises: electronic circuits to automatically control to a set value the amount of light emitted by the phototransmitter and received by the regulation photoreceiver; - an analog/digital converter to deliver a digital signal representative of the light received by the measuring photoreceiver and of the reflectivity of layers traversed by the probe; 20 ~ a reversible counter stage to count up or down, according to the direction of rotation of a graduated dial of an optical rotation sensor, pulses delivered by this sensor and accordingly constantly determine the distance of penetration of the probe into the carcass; 25 - a data acquisition stage including a microprocessor, a temporary memory and a permanent memory containing a first operating software and a first application software ; - said microprocessor operating under the control of 30 said first application software being adapted to : (1) periodically call the contents of the output stages of the analog/digital converter and the reversible counter stage during a probe withdrawal phase; 252213 26 (2) combine the two numbers present at a moment in these output stages so as to produce two fields associated with measuring bits ; (3) apply these bit fields to a temporary memory so 5 as to progressively constitute a frame of raw data corresponding to the simultaneous light reflectivity and probe depth measurements carried out during a pricking operation. 10. Measuring device according to claim 9, wherein : - the microprocessor of the data acquisition stage 10 operating under the control of the first application software is adapted to transfer at the end of each pricking operation each frame of raw data to a data management stage ; - said data management stage including a microprocessor a temporary memory and a permanent memory containing a second operating software and a second application software, push-buttons and a display device so as to establish an interactive link between said data management stage and an operator ; - said microprocessor operating under the control of 2o the second application software is adapted to carry out the following operations : (1) in response to instructions from the operator using to this effect the push-buttons/ display on the display device the menu of various possible functions 25 of the data management stage ; (2) in response to the instructions from the operator, update an identification number of the carcass to be treated and store this number in the temporary memory; (3) store in the temporary memory the raw data frame 30 transferred by the microprocessor of the data acquisition stage ; (4) analyse the stored raw data frame s< there characteristic points to be retained 252213 27 the value of the meat quality parameter concerned ; (5) store the depths of these characteristic points in the temporary memory; (6) order the functioning of an alarm should the 5 characteristic points in question be unable to be detected in the frame of the raw data analysed, said alarm informing the operator that the pricking operation carried out is incorrect and needs to be restarted ; (7) combine the depths of the characteristic points 10 detected in two frames of raw data read on a given carcass according to an equation conforming to rules applicable to a sought-after quality parameter relating to the type of carcasses measured so as to produce a digital value representative of this parameter; (8) store this digital value in the temporary memory; (9) display the latest digital value calculated on the display device; (10) increment by one unit the carcass number 20 corresponding to the next raw data frame to be received from the data acquisition stage ; (11) in response to an instruction from the operator, transfer to a central computer the contents of the temporary memory. 28 FIG 6 & FIG 7 1. REFERENCE 2. COUNTER 3. PERMANENT MEMORY 4. ANALOG/DIGITAL CONVERTER 5. MICROPROCESSOR 6. PULLEY 7. OPTICAL SENSOR 8. REVERSIBLE COUNTER 9. TEMPORARY MEMORY 10. PERMANENT MEMORY 11. MICROPROCESSOR 12. PUSH-BUTTONS 13. DISPLAY DEVICE 14. TEMPORARY MEMORY FIG 8

1. REFERENCE POTENTIOMETER

2. REFERENCE LIMITATION

3. POTENTIOMETRIC DIVIDER

4. ELECTRONIC AUTOMATIC CONTROL

5. ROTATIONAL SPEED BRIDGE

6. DIRECTION LOGIC

7. CONTROL LOGIC

8. SHORT CIRCUIT