JPH01129135A - Automatic measurement for yarn density per unit length of strip article to be moved - Google Patents

Abstract

PURPOSE: To measure a string density per unit length of a band-shaped object to be moved automatically by detecting light through the band-shaped object using a number of sensor elements arranged on a plane and converting it to a digital signal for calculation. CONSTITUTION: A band-shaped object 1 is transmitted through light by a flash source 1 and the transmission light is detected by a number of sensor elements arranged on a plane and are converted to digital signals 4. The digital signals are stored at an image memory 5 and are displayed 7 by a computer 6. A calculated image is inspected in terms of brightness by the computer 6 and is properly applied to the exposure time of the flash source 2 at the time of exposure shortage or exposure excess. Then, the result is displayed by the computer 6 and the string density per unit length of the band-shaped object 1 to be moved is automatically measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for automatically measuring the thread density of a unit length of a moving strip-like article, for example a C-shaped piece.

[Conventional technology]

Determining the number of warp and weft yarns, that is, the thread density per article length lam, is particularly difficult for operators during the production process.
It is of critical importance to the way in which the finishing of an article is carried out, when it has to be carried out. If it is assumed that the normal or unstressed state of the article is known for a given target value (characteristics related to the article), then the internal tension state can be indirectly used for the recognition of thread density. We can conclude. In this case, it can be considered from only physical facts that when the article shrinks, the number of threads per length 1c+a of the article increases due to the compression process, and the number of threads per cm of article length decreases due to the tension of the article in the longitudinal direction. 1
be done.

Therefore, if these changes are recognized within the normal production process, the internal tensions of the article during the entire production process become clearer. Unacceptable tensions and elongations are immediately detected, so that immediate countermeasures can be taken against the cause of the event.

In practice, this kind of measure is not available today. They rely on their luck and hope that, through their experience in programming each machine, they will be satisfied with the overall result at the end of the finishing process.

As is well known, fabrics must be freed from internal tension such that only a residual shrinkage value of ±1% remains within the fabric. These requirements are issued by the ready-made product manufacturing industry and must be complied with absolutely.

To test this internal tension, the ironing test according to the DIN ill standard is now applied as a standard. Articles are also subjected to this standard ironing test, for example in ready-made goods manufacturers.

As soon as a result outside the permissible tolerances occurs, such articles are rejected as unprocessable (not ready for sewing).
. This shrinkage problem therefore exists in every textile manufacturer and finishing manufacturer. For items that have already been finished, such returns are difficult to repair.

Rather, an 8I @ shrinkage process has to be applied, which greatly impairs the final finish properties.

Shrinkage usually first causes loss of gloss, increases article thickness, and results in rough and uneven surfaces.

The article is again in a nearly raw state. Usually such articles have to be completely refinished once again, which involves very high expenditure and disrupts the normal production process.

With regard to the internal tension state being taken into account in an optimally preferred manner of operation, conventionally only small changes in the fiber structure could be discerned by analytical examination before and after each processing step.

Such evaluations were performed manually on product samples in the laboratory. It was only possible to determine the thread count purely experimentally by manually counting the threads per test surface. These tests are very laborious and are by nature only performed in very large companies, where they are time-consuming and the items are well standardized and therefore large numbers of codes are used.

Small and medium-sized enterprises, especially wage-side finishing processors, suffer from the problems mentioned above regarding product diversity.

These contractors today still work purely intuitively and by chance, relying on the experience of individual experts.

This is where the idea of the present invention begins.

[Problem to be solved by the invention]

The problem on which the invention is based is that the thread density can be quickly and well determined even at high web speeds and can be done relatively easily for webs that are moved, especially for textiles and other structures. The object of the present invention is to demonstrate a method for automatically determining the number of warp and weft threads in a planar formation.

[Means to solve the problem]

According to the present invention, this problem is solved by transmitting light through a strip-shaped article by a flash light source, detecting the transmitted light by a large number of sensor elements arranged in a plane, and converting it into a digital signal.
These digital signals are stored in an image memory, then calculated by a computer and the calculation results are displayed by the computer to solve the problem.

Preferably, the calculated image is checked for brightness by a computer and the exposure time of the flash source is suitably influenced in case of underexposure or overexposure.

Advantageously, the sensor element is a component of a CCD planar image camera.

The method according to the invention has a field of use that is of great practical interest.

l) To measure and determine the thread count (thread density) before and after each processing step as a quick measure to solve problems.

2) After setting the target value (for example, regarding the reference sample), the adjustment amount
To create a control circuit that can obtain the desired value (target value - actual value).

If there is a deviation between the target value and the actual value, the machine, for example shrinking machine, dryer, steaming machine, press machine, setting machine, fulling machine, etc. It is possible to adjust the influencing parameters in the washing machine and the like.

3) For use as a testing device for monitoring the internal tension state of a strip-shaped article as it progresses within the production process.

In this case, the circuit must be designed in such a way that simultaneously with the measured value of the thread density between the desired value and the actual value, this percentage deviation is determined and this deviation is compared with the permissible tolerance range. Therefore, as soon as the percentage deviation between setpoint value and actual value exceeds the permissible tolerance range, a signal or a switching pulse must be supplied so that such a strip is recognized.

All these measures increase the reliability of the manufacturing process and prevent unacceptable residual shrinkage values.

〔Example〕

The invention will be explained in detail below with reference to the drawings.

At 1, a moving strip is shown, which has to be measured for thread density per unit length, e.g. I cm. A flash light source 2, such as a flash tube, is arranged below the moving strip-shaped article 1, and a large number of sensor elements arranged in a plane are provided above the strip-shaped article 1, and these sensor elements C for detecting mow images
This is a component of the CD-plane image camera 3 (II & load coupling element).

The flash light source 2 is transmitted through a specific surface of the strip to be tested, the transmitted light acting on the individual sensor elements.

An analog-to-digital converter is indicated at 4, which converts the data obtained by the planar image camera 3 into digital signals, which are subsequently transferred to the connected image memory 5. is memorized.

These stored signals are then calculated in a computer 6, where the calculation results are suitably displayed.

A monitor 7 is associated with the image memory 5, which provides a suitable image of the fabric.

In practice, only one textile image is first detected at a very specific exposure time and this test image is displayed on the monitor 7. If this displayed image is not usable for the method, a new image is determined in the computer 6 and with an exposure time suitable for the article to be tested and processed in the same previously described manner. In this case, the light transmittance of the various articles will of course be a factor.

Operation bag so that you can properly control the exposure time of flash source 2! 8 is provided, and this operating device is connected to the computer 6 via, for example, a coupling element 9 (interface).

For reasonable image quality, gray values greater than 128 are
All gray values less than 128 are interpreted as "black". "Black-white" transitions are thereby determined in all rows and all columns of the planar image camera 3. From this result, the frequency (period) of each interval of the threads of the strip-shaped article 1 is determined.

The values for the frequencies of the associated interval values are stored in the calculator 6 in tables for rows and columns.

These values according to the table are the formula (n interval = frequency of Iia interval) Processed by

A weighted average of the period lengths is thereby obtained. The result directly yields the actual value of the number of warp and weft threads per unit area, that is, the thread density. This program allows you to set target values without any hassle. This measurement result can be expressed as a percentage deviation from the target value. The tolerance limits introduced into the calculation can be defined in terms of percentages.

This allows completely automatic regulation of the contraction process.

[Brief explanation of the drawing]

The drawing is a block diagram of the method according to the invention. 1...Band-shaped article, 2...Flash light source, 5...Image memory, 6...Computer patent applicant Helmut Gomolka Procedural Amendment (Method) November 1, 1988

Claims (1)

[Scope of Claims] 1. Light is transmitted through a strip-shaped article (1) by a flash light source (2), and this transmitted light is detected by each number of sensor elements arranged in a plane and converted into digital signals, and these per unit length of the strip-like article to be moved, characterized in that digital signals of How to automatically measure thread density. 2. The calculated image is checked for brightness by the computer (6) and the flash source (2) is activated in case of underexposure or overexposure.
2. A method according to claim 1, characterized in that the exposure time of . 3. One of claims 1 and 2, characterized in that the sensor element is a component of a CCD-planar image camera (3).
The method described in.