The invention relates to a method of processing signals obtained from scanning textile fabrics.
EP 1 100 989 discloses for example a method of evaluating faults in textile fabrics by means of which the permissibility of faults in fabrics is determined on the basis of the length and contrast of the faults by comparison with the fault-free fabric. Here, the longer the fault and the greater the contrast, the more probable it is that the fault concerned is undesirable. The same actions are then always provided for each fault which is recognised as such and is undesirable, or in other words unacceptable. That means that an undesirable fault in a textile fabric has the result that the fault is removed if possible or the relevant part of the fabric is sold at a lower price or is not sold at all, and hence becomes a reject.
One disadvantage of this-known method can for example be seen in the fact that a sharp line is drawn between permissible and impermissible faults. This line or limit is selected by weighting opposing factors such as the economics and the quality of the fabric. To guarantee economics, the limit should be selected such that as few faults as possible result in rejects. To guarantee quality, as far as possible all faults should be recognised as such and indeed removed, or the fabric must be counted among the rejects. These opposing factors result in the decision on permissible or impermissible faults becoming a compromise which is undifferentiated and difficult to find.
It is therefore an object of the present invention as characterised in the claims to provide a method which makes it possible to evaluate the faults in a fabric in a highly differentiated way and which results in targeted actions on the basis of the faults that are recognised.
This object is achieved in that signals produced when textile fabrics are scanned are used to derive values for defined parameters such as contrast, intensity, length, direction and so on. Limit values which are used to determine faults in the fabric are also predetermined for the parameter values. Value ranges which define categories of faults in the fabric are determined for the faults, that is to say the parameters characterising them. For each category of fault in the fabric, the distribution of faults in the fabric is determined and where necessary, as a function of the category and distribution of the faults in the fabric, an action to be performed on the fabric is triggered, such as counting the faults, stopping the drive for the fabric, triggering an alarm, ignoring the faults or marking the faults.
The advantages achieved by the invention can be seen in particular in the fact that both the economics of manufacturing a fabric and the quality of the fabric can be improved thereby in that the faults and their distribution result in actions which are highly dependent on how detrimental the faults actually are to use of the fabric in concrete terms. This means that the evaluation of the fabrics can be adapted to all possible circumstances in a very precise and highly differentiated way.
The invention will be explained below in more detail with reference to an example embodiment and to figures, in which:
To process analog or digital signals from the scanning device 2, various memories 8, 9, 11, a counter 10, calculators 12, 13, 14, an input and output unit 15 and an actuator 16 are provided, and these are connected to one another and to the other elements by way of connections 17, 16, 19, 20, 21, 22, 23, 24, 25, 26, 27 and 28.
The invention operates as follows.
Preferably, before scanning of the fabric 1 starts, there must be a predetermination of what constitutes a fault and what does not. Thus, first of all parameters have to be selected which are to characterise faults, and limit values for the selected parameters have to be predetermined, the exceeding of which indicates faults in the fabric. Furthermore, for values of the selected parameters which exceed the limit values, value ranges which define categories for the faults must also be predetermined. Then, details of the permissible distribution of the faults and of actions to be triggered when the predetermined values are exceeded must also be predetermined. This can be done by manual input by way of the input/output unit 15. Some of the values may however also be fixed beforehand, that is to say these values are already permanently stored in the memories.
As the fabric 1 moved by the drive 3 is pulled past the scanning device 2, lines n, n+1, n+2, n+3, n+4, etc. (
It is thus possible in accordance with the invention to predetermine by way of the input/output unit 15 the type of faults or fault categories which are dependent on and specifically predetermined by the type of textile fabric 1 present. For a woven fabric, the following fault categories are for example conceivable:
The user may also define their own fault categories, however, and input appropriate value ranges for the parameters.
For a knitted fabric, the fault categories could be the following:
For all these faults, values apply to the parameters defining the category concerned, such as:
The parameters stored temporarily in the memory 8 are compared in the calculator 12 with predetermined values for these parameters from the memory 9 which define categories, and are in this way allocated to categories. For example, as a parameter the length of a fault in the weft direction may be predetermined, with for example 0.5 cm, 3 cm and 10 cm being predetermined values. If the measured length of the weft fault is larger than 10 cm, then it goes into the “long weft fault” category; if its length is between 3 and 10 cm it goes into the “medium weft fault” category; and if its length is between 0.5 and 3 cm it falls into the “short weft fault” category.
In addition to the categories mentioned above of a first type, determined by the properties of the faults, categories, of another type may also be predetermined or defined which characterise the distribution of faults on the fabric 1. Examples which may be given of this other type of categories are:
In this connection, a minimum number of faults should be input by way of the input/output unit 15 for example for periodic faults, after which regularly occurring faults are to be considered periodic.
For a cluster of faults, once again the number of faults should be input by way of the input/output unit 15. The number of faults in this case relates to a minimum number per reference length of the fabric 1 after which the faults are to be considered a cluster of faults. It is possible to select the value ranges of the individual parameters individually for definition of the categories and the distribution.
Once the fault categories of the first type, which are input as fixed values beforehand in the form of the value ranges associated therewith, have been defined from suitable inputs, the device in accordance with
The calculator 14 may convey counted faults to the input/output unit by way of the connection 28 for display. This may also apply with an alarm. If the drive 3 is to be stopped, a corresponding signal is passed by way of the connection 26 to the actuator 16 and by way of the connection 27 to the drive 3.
For the parameters, the user can input by way of the input/output unit 15 values for any conceivable fabric which predetermine categories of the first type which seem important to them. It is, however, also possible, instead of inputting them directly, to input parameters by deriving them from the signals from the scanning device 2, in that for example measured values are output by way of the connection 20′ to the input/output unit 15 and the memory 9 and these measured values are allocated to a category by way of the input/output unit 15.
The elements illustrated in the figure such as memories, calculators, etc. may be grouped into function blocks of a data processing program. However, they may also take the form of individual fixed blocks of a circuit for signal processing.
The method described above may also be illustrated in the table reproduced below. Here, in this example, only one parameter is mentioned, defined by value ranges. It would however also be possible to list other parameters defined by other values or ranges. A fault category is always defined by a combination of preferably a plurality of parameters with value ranges for each parameter.
Actions:
+ = count,
! = sound alarm,
□ = stop drive,
− = ignore
Number | Date | Country | Kind |
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176/03 | Oct 2003 | CH | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CH04/00613 | 10/7/2004 | WO | 7/13/2006 |