Zeljko Hocenski

Improved Canny Edge Detector in Ceramic Tiles Defect Detection

Image processing is very often present as a method for visual inspection in industry. Automated systems for visual inspection are very important part of the quality control in production line. Quality control has been mostly performed in hard work conditions. Using automated visual systems quality control becomes easier. It performs faults detection and final quality control. In this paper we present the method for faults detection based on edge detection techniques. Edges and faults on ceramic tiles were detected using Canny edge detector. Problem of defining hysteresis thresholds was resolved with a histogram subtraction method. Method was implemented on various types of faults: edge and surface faults

Failure detection and isolation in ceramic tile edges based on contour descriptor analysis

Todays industry is based on the principle of automatics. In order to increase production quality and improve production yield that reduces production costs, there is tendency to automate every phase in the production line and if possible to replace the human resource entirely. Ceramic tile industry is not an exception. In the ceramic tile production line almost every phase is more or less automated. The only part which is least automated is visual inspection and classification of a ceramic tile. In this paper we present a method for visual inspection of ceramic tile edges, their failure detection and isolation using a machine vision system. For edges inspection, detection and failure isolation we use a method based on contour tracing and description of tile edges. The method developed generates a contour reference descriptor based on directional contour tracing, determines tile orientation for referenced preprocessing and localizes and isolates the failure. The method is tested and results are given for several types and sizes of ceramic tiles.

A Simple and Efficient Method for Ceramic Tile Surface Defects Detection

In this paper is developed and presented method for failure detection in ceramic tile production using computer visual diagnostic. This method is focused on detecting of failures on ceramic tile surface in manner of highly contrasted dot shaped formation incorporated into ceramic tile surface which are result of failures in production chain. The ceramic tile quality grade is directly influenced by amount and type of failures on its surface and with presented method in this paper we try to contribute to automating of final stages in ceramic tile producing chain. This presented and developed method is optimized for fast execution and for efficient detection of mentioned failures without need for reference tile comparison system.

The Edge Detecting Methods in Ceramic Tiles Defects Detection

The requirements of modern manufacturing industry caused the increase of implementation of the automated systems. Their main aim is to improve visual inspection and quality control. In the ceramic tiles industry the quality control is performed in real time conditions so that tiles are classified and removed if they have defects in color, dimension or on the surface. The need for defect detecting methods occurred. Image processing methods has already been applied in recognizing defect on images. In that purpose some methods for detecting edges of images are described in this work. These methods were applied on images of ceramic tiles with defect in color and surface

Ceramic tiles failure detection based on FPGA image processing

This paper presents one method about automation of tile surface and texture diagnosis. Final stage of tile manufacturing deals with surface and edge defects detection, and is still not an automated part of production. We used computer visual diagnosis and FPGA-based embedded hardware digital design to classify tiles according to surface and edge defects. In order to reduce computing time, we used tile images from line camera and the FPGA embedded parallel image processing unit designed with VHDL.

Image comparison method for visual quality control based on matrix decomposition

The image processing applied on the original tile image and the replica images in serial production is used for visual quality control. The image of a tile that contains no visual quality error represents the original image. The images of the tiles from the production line that could contain some of the visual quality errors represent the replicas. The image processing is based on the image matrix decomposition method. The matrix form of the original image is transformed to a vector. The images made by the variations of a good original image are transformed to the matrix made by such vectors. Using the SVD of the matrix of variations of the original image makes the image comparison duration shorter. The number of computer operations decreases by using SVD approximation by a lower rank matrix. The SVD calculation of the matrix is done just once so that the image processing time is shorter. Too low a rank of the matrix could yield bad comparison results. The development and testing of this method are used for an early design of the computer aided visual control.

Neural network based detection of defects in texture surfaces

In this article we present an algorithm for automatic detection of surface defects on ceramic tiles. This algorithm is based on the probabilistic neural network with radial basis. To improve sensitivity of the detection procedure an image of the tile is divided into segments and one neural network is made for each segment. The discrete wavelet transform (DWT) is used for the feature extraction in every segment. Maximums of the wavelet coefficients as well as the mean value of the approximation coefficients form an input vector for the neural network. Experimental results of the defect detection for different types of tiles and with different parameters of the algorithm show a high sensitivity and applicability of the proposed procedure.

Undergraduate teaching of real-time scheduling algorithms by developed software tool

Theoretical foundations of scheduling in the course Real-Time Systems of the undergraduate studies program are extended by the usage of the developed visual software tool. The tool enables teaching of simulated fixed-priority scheduling algorithms. The user simply sets the simulation and algorithm properties and loads the prepared input task sets from the database. Results are obtained within the program or from external applications. The paper deals with the problem of scheduling the mixture of periodic and aperiodic tasks in a uniprocessor system. Results are displayed in the form of a flow report, table report, and diagrams of dependencies of evaluation parameters on the change of periodic and aperiodic workload. The flow report explains the algorithm behavior and the table form and dependency diagrams enable a more precise scheduling analysis and mutual comparison, respectively. Some of the evaluation parameters are the following: aperiodic response time, number of tasks with missed deadlines, utilization of resource and server tasks, resource-breakdown utilization. The software tool improves teaching of the course and the final success of students regarding relevant exam exercises.

LED panel illumination design of a control system for visual inspection of ceramic tiles

During whole production process there is a possibility of mechanical damage of ceramic tile during transporting from one production phase to another. Because of that, last phase in ceramic tile production process is visual inspection and quality control. Today in most cases in products quality control are used human resources but because of human resources limits, this stage of process needs automatization. Regardless, if we use human resources or machined vision systems (digital cameras) for visual inspection, we need to ensure quality lighting of ceramic tile. In this paper is shown how to make quality lighting for ceramic tile quality inspection using machine vision systems. Advantage of this lighting is in using Light Emitting Diodes instead of light bulbs.

A Self Manageable Rule Driven Enterprise Application

In this paper we present a design and a prototype of a self-manageable application. Self management is accomplished by usage of a rule based autonomic manager. The application demonstrates principles for combining enterprise servers and custom developed components into a system with self-configuring, self-healing and self-optimizing characteristics.