Wonbae Park

Content-based image retrieval using new color histogram

This study has proposed a new method of color representation, and a method of similarity measurement in order to overcome the disadvantages of a color histogram. The existing color histogram intersection method uses only the frequency value of the same color, after color quantization; which causes quantization errors. To reduce this error, it calculated the mean value of RGB color components and color frequency in each color region, selected them as the representative value of the similar region of a relevant color, then stored this in the DB as a feature vector, and finally, measured the similarity between color images by applying fuzzy theory. As a result, the color histogram has retrieved similarity between images more precisely than the existing method did. The study experimented on 1,000 color images by the new color histogram retrieval method, and found it more precise than the existing method.

Experimental confirmation of suspended few-layered graphene on a Cu substrate grown via the CVD method and correlated with the electrical performance on a PET substrate

We present that the Raman 2D and G peak of graphene film fabricated via chemical vapour deposition (CVD) blue-shifts on the relatively even Cu foil domain, showing a rather compressive strain effect compared to the uneven domain. We experimentally figure out that the relaxing compressive strain, to minimize the adhesive interaction between the graphene and the Cu surface, has one of the critical roles in forming suspended few-layered graphene. The nanoscopic conductance investigation also reveals that the current flow is dominantly measured at the uneven nano-terrace domains rather than at the even, further signifying the importance of a detailed underlying Cu surface morphology.

Experimental observation of local electrical signature of suspended graphene grown via chemical vapour deposition method

We employ electrostatic force microscope (EFM) techniques to explore local electrical properties of suspended graphene on Cu foil, SiO2/Si and PET substrate. By using electrical modulation of amplitude in a tapping mode atomic force microscope tip, we can obtain distinguished electrostatic force amplitude mapping of graphene on various substrates. In particular, at nano-valley domains on Cu and a SiO2/Si surface, relatively weaker electrostatic attractive interaction is observed than at nano-peak domains. In SiO2/Si, we find that electrostatic force distribution of graphene still follows the substrate surface morphology. Furthermore, employing EFM to graphene on a PET system can be suggested as a facile tool to investigate electrical performance of graphene.

Characterization of local charge distribution of polyethylene terephthalate film and influence as a graphene substrate

We examine local electrostatic force distribution of polyethylene terephthalate (PET) film surface before and after transferring graphene in order to compare the influence of local electrostatic interaction between graphene and PET film in terms of the sheet resistance value of deposited graphene. By using the electrical modulation of amplitude in a tapping mode AFM tip, we can obtain the distinguished electrostatic force amplitude mapping of graphene. We determine that different electrostatic attractive interactions between Au-coated tip and bare PET are present and the observed difference can affect the graphene formation and electrical performance, which correlates with the sheet resistance difference.

Contend Base Image Retrieval using Color Feature of Central Region and Optimized Comparing Bin

In this paper, we proposed a content-based image retrieval using a color feature for central region and its optimized comparing bin method. Human`s visual characteristic is influenced by existent of central object. So we supposed that object is centrally located in image and then we extract color feature at central region. When the background of image is simple, the retrieval result can be bad affected by major color of background. Our method overcome this drawback as a result of the human visual characteristic. After we transform Image into HSV color space, we extract color feature from the quantized image with 16 level. The experimental results showed that the method using the eight high rank bin is better than using the 16 bin The case which extracts the feature with image`s central region was superior compare with the case which extracts the feature with the whole image about 5%.