Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Quality evaluation
Reexamination Certificate
1999-05-21
2001-12-25
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Quality evaluation
C702S108000, C702S085000, C702S075000, C356S328000
Reexamination Certificate
active
06334092
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for measuring the quality, such as internal sugariness or the like, of the greengrocery (fruits and vegetables) such as oranges, melons, watermelons, and so on on a non-destructive basis and, more particularly, to a processing circuit for processing initial data obtained by the measurement at higher speed and with higher accuracy.
2. Related Background Art
In general, the internal quality of the fruits or vegetables before shipping has been evaluated heretofore mainly by visual inspection of skilled inspectors. Certain fruits or vegetables, if harvested or shipped in a full ripe state, would undergo deterioration of taste, saccharification of sarcocarp, etc. on the market. Therefore, such fruits or vegetables are harvested in an unripe state and thereafter are made to stand under fixed temperature to effect afterripening into an edible state. It was also conventional practice to judge completion of the afterripening by visual inspection of inspectors as above, but it was difficult to make an accurate judgment, because there were no definite criteria for such evaluation of the internal quality of fruits or vegetables.
On the other hand, based on the fact that when near-infrared light is projected onto the fruits or vegetables, such components as sugars, acids, or the like in the fruits or vegetables absorb light of specific wavelengths, it is possible to know the internal quality, such as the sugariness or the like, of the fruits or vegetables by analyzing the light transmitted by the fruits or vegetables and there are known methods for determining the internal quality of the fruits or vegetables on a non-destructive basis, using the transmitted light of the near-infrared light.
Specifically,
FIG. 13
is an example to show a schematic diagram of a measurement device for measuring the internal quality of the fruits or vegetables. In
FIG. 13
, inspected objects
5
, which are the fruits or vegetables, are conveyed on a conveyor system
10
, for example, such as a conveyor or the like, and in that state the internal quality of the inspected objects
5
is measured continuously. First, the existence of an inspected object
5
on the conveyor system is checked by a position sensor
11
. Then a light source
1
radiates light having a predetermined frequency region (which will be referred to hereinafter simply as light) toward the inspected object
5
at a predetermined position A on the conveyor system. Among the radiated light, light of certain wavelengths is absorbed by sugars or the like existing in the inspected object
5
and thereafter the light is transmitted by the inspected object
5
to the outside. This transmitted light is measured by a light receiving element
2
and the transmitted light obtained by this measurement is analyzed in a signal processing device
12
, thereby permitting us to know the internal quality of the inspected object
5
.
In the practical evaluation of the internal quality of fruits or vegetables, however, the light used in the spectral analysis of fruits or vegetables has a wide frequency region and, in order to obtain the accurate internal quality by signal processing in practice, it is necessary to split the frequency region into a plurality of frequency regions and carry out the signal processing for each of the split frequency regions. Conceivable methods for the division and signal processing of the frequency region include methods of 1) and 2) described below.
1) Interference filters, each transmitting only light in a predetermined frequency region, are prepared in the number of their frequency regions equal to the number of split measurement frequency regions, the filters are continuously changed one by one at a light receiving portion of the light receiving element, so as to continuously send the transmitted light of the split frequency regions to the signal processing device, and the signal processing device carries out the signal processing therewith. One measurement operation for the measured frequency region is completed after the filters all have passed the light receiving portion.
2) For example, as described in Japanese Laid-open Patent Application No. 7-22984, a diffraction grating for separating measured wavelengths is placed at the light receiving portion, the transmitted light after split is guided to an array having storage-type sensors in the number according to the number of separate regions, and after completion of one measurement, data stored is successively subject to signal processing by a single signal processing circuit (including an amplifier etc.).
Since the permissible time for the evaluation of quality in a grading process of fruits or vegetables is very short, the evaluation of fruits or vegetables under conveyance on the conveyor system has to be carried out continuously for the fruits or vegetables. However, since the internal quality of the fruits or vegetables varies considerably, depending upon measured regions thereof, the evaluation has to be carried out on a basis as continuous and in a range as wide as possible. For the accurate evaluation, sufficient light energy has to be accumulated with reception of the transmitted light.
In the case of the method of 1) described above, however, since the fruit or vegetable moves during switching of the interference filters, the measured regions are also shifted with the switching of the frequency regions and data for one frequency region out of the split frequency regions is discontinuous and partial in the measured region on the fruit or vegetable. Further, since the data obtained for the respective split frequency regions is one at different measured regions for the same reason, it is difficult to obtain the accurate measurement result of internal quality. The measurement time for each split frequency region becomes shorter and shorter as the number of split frequency regions increases. This would pose a problem that it is difficult to obtain the sufficient light energy of the transmitted light or the like.
In the case of the method of 2) described above, though the diffraction grating splits the transmitted light at one time, the data stored has to be sent serially from the array to the signal processing circuit. Therefore, data storage start times and storage end times for the respective split frequency regions are shifted in order according to the data transfer times. Since this temporal deviation in the data storage timing for each split wavelength is as small as ten and several msec, the problem of discontinuous measured regions on the fruit or vegetable or different measurement positions of data obtained for the respective split frequency regions, and the problem of decrease in the light energy stored per unit time are not so serious as compared with the case of the method of 1). This method was, however, inadequate in a sense of obtaining a more accurate measurement result of the internal quality of fruit or vegetable or in a sense of decreasing the permissible time for the measurement of quality. Further, this method needs a step of initialization to erase the data stored in each sensor on the array after completion of one measurement. This posed a problem in decreasing the time necessary for the measurement.
In the method 2) described above, a conceivable means for solving the above problem is an approach for increasing the storage time for each frequency region to several ten msec. In this approach, however, if during a certain period within the storage time abnormal intensity data appeared, for example, due to reception of external light other than the transmitted light on the light receiving element or due to the dust or the like attached to the fruit or vegetable, it was difficult to find out a profile of intensity data in the storage time and there was a possibility that the data including the abnormal value was used as it is.
Actual intensities of the transmitted light vary large depending upon the frequency regions and it is thus necessary to select
Aoki Toyohiko
Hashimoto Hirotsugu
Hoff Marc S.
Kubovcik & Kubovcik
Mitsui Mining & Smelting Co. Ltd.
Tsai Carol S
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