CN103018250B

CN103018250B - Image detection system for seamlines of fabric in calendering process

Info

Publication number: CN103018250B
Application number: CN201210533206.1A
Authority: CN
Inventors: 潘如如; 刘基宏; 高卫东; 朱博
Original assignee: Jiangnan University
Current assignee: Zhejiang Shengli Textile Co ltd
Priority date: 2012-12-12
Filing date: 2012-12-12
Publication date: 2014-12-24
Anticipated expiration: 2032-12-12
Also published as: CN103018250A

Abstract

The invention relates to an image detection system of seamlines of fabric in a calendering process, belonging to the field of novel textile detection. In the calendering process, when a hot rubber roller irons the seamline of the fabric, as the thickness of the seamline is increased suddenly, a trace can be left on the surface of the rubber roller, and the trace can be copied onto the surface of the follow-up fabric which is ironed to affect the appearance and the planeness of the fabric surface and even produce defective products. Manual operation and control of the lifting of the hot rubber roller to avoid the seamlines has the disadvantages of visual error, low reaction speed, fatigue error and the like, and can cause excessive avoidance or unavoidance of the seamlines. The invention provides a fabric seamline automatic detection system based on embedded vision. A motion image of the fabric is acquired by a CCD (charge coupled device) camera and input into a DSP (digital signal processor), an embedded algorithm is adopted for detecting whether the seamlines exist in the image or not, and when the seamline is detected, a machine is controlled to lift the rubber roller so as to automatically avoid the seamline, so that the image intelligent detection of the seamlines of the fabric can be realized and the labor intensity of a worker can be reduced.

Description

Image detection system for fabric seam line in calendering process

Technical Field

The invention relates to an image detection system for a fabric seam line in a calendering process, which comprises image acquisition, image processing and the like of a moving fabric, belongs to the field of novel textile detection, and particularly relates to the image acquisition, processing and other technologies of embedded machine vision.

Background

In the calendering process often involved in textile enterprises, when a hot rubber roller irones a seam line of a fabric, a mark is left on the surface of the rubber roller due to sudden increase of the thickness of the seam, and the mark can be copied to the surface of the subsequently ironed fabric, so that the appearance and the flatness of the cloth surface are influenced, and even defective products are generated. Therefore, in the traditional calendering process, the lifting of the hot rubber roller needs to be controlled by manual operation to avoid the seam line, so that the quality problem is avoided. However, this method has visual errors, reaction speed errors, fatigue errors caused by continuous tension, and the like, and these subjective factors may cause excessive avoidance or insufficient avoidance of the seam line.

In recent years, with the development of image processing technology, the application range thereof is becoming wider and wider. In the textile industry, many detections related to fabrics depend on the vision of detection personnel, such as fabric defect detection, foreign fiber detection and evaluation, and the development of image processing technology, so that the problems are expected to be solved by an automatic method.

Aiming at the problems in the seam line detection in the calendering process, the invention provides an automatic detection system for the seam line of the fabric based on an image analysis technology. The digital camera is used for collecting the moving image of the fabric in the calendering process, the moving image is input into the embedded chip, whether a seam line exists in the image or not is detected, and when the seam line is detected, the rubber roller in the machine is automatically controlled to be lifted up to avoid the seam line. The implementation flow of the detection system provided by the invention is shown in fig. 1.

Disclosure of Invention

The invention aims to provide an image detection scheme of a fabric seam line in a calendering process, which is used for realizing automatic detection of the fabric seam line. The technical scheme adopted by the invention is as follows:

(1) the digital camera is used for completing the collection of images of the moving fabric, the images are input into the embedded chip through the data communication interface, the automatic detection of the seam line is completed through image analysis, when the fabric seam line is detected, the rubber roller is controlled to be automatically lifted up to avoid the fabric seam line, and an exemplary diagram of the system is shown in figure 2;

(2) inputting the collected image into a DSP development chip through a data communication line to complete embedded visual detection, wherein an AV interface is adopted as a data communication interface;

(3) judging whether a seam line exists in the image or not according to the characteristic parameters of the fabric image;

(4) when the fabric seam line is detected, the signal is transmitted to the single chip microcomputer or the PLC through the output interface so as to control the lifting of the rubber roller.

Drawings

FIG. 1 detection process of fabric seam line

FIG. 2 schematic view of a fabric seam line detection system

FIG. 3 Fabric seam line image

Detailed Description

The digital camera is arranged above the moving fabric, and it should be noted that the detection system is positioned in front of the rubber roller, when the seam line is detected, a trigger signal is output to control the lifting of the rubber roller, and the moving distance of the fabric should be less than the distance between the detection system and the rubber roller within the detection and control time.

Since the width of the seam line of the fabric is consistent with the width of the fabric, the detection does not need to shoot the image of the whole seam line, but only needs to shoot a part of the seam line. Therefore, when the digital camera is installed, the digital camera is located on one side of the moving fabric, the camera is about 20cm away from the fabric, the system provides a double-side transmission white light source, so that the seam line in the shot fabric image is clear and recognizable, and fig. 3 is the fabric seam line image shot in the actual detection system.

The image data is transmitted to the embedded chip through the data connecting line, the data line of the AV interface is adopted by the system, and the DSP (DM642) is adopted by the embedded chip.

In the DSP chip, calculating the parameters of the mean value and the standard deviation of each frame of transmitted image, and further calculating the characteristic parameters of the variation coefficient of the image, wherein the calculating method comprises the following steps:

<math> <mrow> <mi>CV</mi> <mo>=</mo> <mi>σ</mi> <mo>/</mo> <mover> <mi>x</mi> <mo>&OverBar;</mo> </mover> </mrow> </math>

whereinThe mean value is the image mean value, σ is the standard deviation of the gray level image, and CV is the coefficient of variation of the image.

The CV value reflects the relative change of the image gray level, objectively reflects the gray level discrete degree of each group of anti-feathering cloth images, and can be used as a standard for detecting whether a seam line exists or not.

In the system of the present example, a CV value of 0.07 was selected as a criterion for determining the presence or absence of a seam line in the image of the fabric, and when the CV value was greater than 0.07, the presence or absence of a seam line in the image was considered. The value of the judgment basis in the specific example system has close relation with the light source selection of the system and the like, and the optimal judgment value can be obtained through example training.

Claims

1. An image detection system of fabric seam line in calendering technology is characterized in that: the automatic detection of the fabric seam line in the calendering process is realized by using the embedded machine vision; collecting a fabric image by a CCD digital camera, inputting the fabric image into a DSP chip through a data communication interface, and judging whether the image contains a seam line or not by using an image detection algorithm; the system comprises an output interface and a rubber roller connected with a singlechip or a PLC control machine, and when a seam line is detected, a trigger signal is output to control the machine to lift the rubber roller and avoid the seam line;

wherein,the mean value is the image mean value, σ is the standard deviation of the gray level image, and CV is the coefficient of variation of the image.

The CV value reflects the relative change of the image gray level and objectively reflects the gray level discrete degree of each group of the anti-feathering cloth image, and is used as a standard for detecting whether the seam line exists or not.

2. The system of claim 1, wherein: the CCD digital camera is used for realizing the acquisition of the moving fabric image, the resolution of the camera is more than 640 pixels multiplied by 480 pixels, and the seam line in the acquired fabric image is required to be clear and distinguishable.