Sang-Gug Park

Vision technique for the recognition of billet characters in the steel plant

This paper describes vision technique about the real time billet characters recognition system in the steel production line. Normally, the billets are mixed at yard so that their identifications are very difficult and very important processing. The character recognition algorithm used in this paper is base on the subspace method by K-L transformation. With this method, we need no special feature extraction steps, which are usually error prone. So the gray character images are directly used as input vectors of the classifier. To train the classifier, we have extracted eigen vectors of each character, which was included in the billet images. We have constructed vision system for the recognition of billet characters using this algorithm and tested this system in the steel production line. The recognition rate of our system in the field test has turned out to be 98.6 % if the corrupted characters are excluded. In the results, we have confirmed that our recognition system has a good performance in the poor environments and ill-conditioned marking system such as steel production plant.

Development of real-time character recognition system for the steel-iron plant

This paper describes about the development of real-time recognition system for the characters, which was marked at the slab and billet material in the steel-iron plant. Normally, the billets or slabs are mixed at yard so that their identifications are hardly tractable. The characters of these material image can be marked by use three kinds of methods such as auto marking machine, template-marking plate and hand written method. For the recognition of each character, we use KLT, PSV, and CCD & PSVM algorithm for the printed font, template-marked font and hand written font respectively. The font style of slab materials is printer letter. The font style of bloom or billet materials is mixed type with printed font, template-marked font and hand written font. For the application of recognition algorithm, we have developed vision system and installed at the slab and billet processing line of the steel-iron plant. Through the test, we have confirmed that our system has good performance and high recognition rate, 97.6% for slab and 98.6% for billet

Optical encryption system based on circular polarization and interferometer

We propose an optical encryption system using circular polarization based on interferometer architecture. The phase-modulated input image, represented as orthogonal linearly polarized states by interferometer, is encrypted into circularly polarized states whose direction of the rotation is random. In the decryption we use the inverse matrix of polarization-modulation key and can recover the original polarization states.

Finding the information of the ellipse from the optical Hough transform

A new method to find five parameters of an ellipse from the optical Hough transform results is described. The method employs the Hough transform for detection of a straight line and the 1D analysis of the resultant parameter domain. By using this algorithm, we simulated about the ellipses with different positions, and we obtained the information of the ellipse with 94% accuracy in the worst case. To compare the simulation results with the experimental results, we performed optical experiments by using a HT CGH filter. Through the experiments, we showed that our results were very similar to those of the simulation results.

Study on the Librarian Helper Robot System Implementation

This paper suggests improved model of librarian helper robot to diminish librarian workload such as book loans and book returns. The existing unmanned book lending system performs book search and book return at the fixed location. Our system provides book-search through DB, mobile robot control through the Zigbee communication, scanning the RFID tag attached to the book. In the experiment, five-axis multi-joint robot is controlled through Zigbee communication and server PC manages all of the information. The recognition rate about wanted book was about 98 %. Our mobile robot has brought the book exactly to designated place. Through experimentation, we confirmed that suggested model can be applied to the library.

Optical security system based on computer-generated hologram

A new image encoding and identification scheme is proposed for security verification by using a CGH (computer generated hologram), a random phase mask, and a correlation technique. The encrypted image, which is attached to the security product, is made by multiplying PCGH (phase CGH) with a random phase function. The random phase function plays a key role when the encrypted image is decrypted. The encrypted image can be optically recovered by a 2-f imaging system and automatically verified for a personal identification by a 4- f correlation system. Simulation results show the proposed method can be used for both the reconstruction of an original image and the recognition of an encrypted image.