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Budi Hartanto
Universitas Kristen Maranatha
Computer Science & IT Education Health Professions

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Journal : Jurnal Informatika

 1 
GENERATING A SEAMLESS TILING OF A NATURE IMAGE Hartanto, Budi
Jurnal Informatika Vol 8, No 1 (2007): MAY 2007
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1120.699 KB) | DOI: 10.9744/informatika.8.1.pp. 29-36

Abstract

Tiling is a process to create a repetitive - larger size - image. However if the picture on the left side of the original image is not continuous to the picture on its right side, the tiling image will have a virtual vertical line called seam. Meanwhile the virtual horizontal line will appear if the picture on the top side of the original image is not continuous to the picture on its bottom side. The research performed here tries to generate a seamless tiling image by finding the closest match of the fractional source image to the partially build resulted image. From the experiment, it can be shown that the quality of the resulted image are affected by the number of similar elements in the source image, the number of fractional images created from the source image, and the width of the overlap area. Source image with a lot of similar element, high number of fractional images, and wider size of the overlap area have been proven to yield a seamless tiling image.
SIMULATING THE EFECT OF CAMERA LENS IN COMPUTER GENERATED PICTURE Hartanto, Budi; Rosalina, Silvia
Jurnal Informatika Vol 7, No 1 (2006): MAY 2006
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (134.32 KB) | DOI: 10.9744/informatika.7.1.pp. 10-16

Abstract

Original ray tracing method can be used to create picture of objects that are very similar to photographic. However for simplicity, the method mimics a pinhole camera in its model. In pinhole camera all objects visualized in the image generated will be seen sharp. In some cases, this kind of image is acceptable but in other cases it is not. For example, in the movie industry, sometimes it is preferable to get the image that can be focused to a certain object and not to all objects. This effect occurs due to the usage of a lens in a camera. In order to get the same effect to the real camera, then it is necessary to modify the original ray tracing method to use lens in its model. The research performed here has successfully simulating the effect of lens in camera. Therefore only objects that are placed in the lens focus will be seen sharp while the others will become blurry.
THE USAGE OF GRAPHICAL PASSWORD AS A REPLACEMENT TO THE ALPHANUMERICAL PASSWORD Hartanto, Budi; Santoso, Bagus; Welly, Siauw
Jurnal Informatika Vol 7, No 2 (2006): NOVEMBER 2006
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (485.635 KB) | DOI: 10.9744/informatika.7.2.pp. 91-97

Abstract

Alphanumerical password is the password scheme that obligates the users to enter characters as their password. In spite of its popularity, alphanumerical password usually can be cracked easily when it is used by novice users. Since these users usually type their password slowly, unauthorized person can get the password easily by observing the movement of the users' finger as they entering the password. A graphical password is proposed to replace the alphanumerical password. From the experiment it can be shown that none of users graphical password can be cracked, meanwhile 80% of the users' alphanumerical password can be cracked by the researcher. However in average, users need only 4.68 seconds to enter the password in alphanumerical password scheme, meanwhile in graphical password scheme it takes about 39.06 seconds. Hence password entry in the graphical password scheme needs about 8 times longer than in alphanumerical password. Based on this fact, the graphical password may still be considered to be used in applications that do not need a rapid password entry and the system security is becoming the main issue.
Co-Authors - Suwarman Ali Djamhuri Ruli Herman Sitanggang Siauw Welly Silvia Rosalina