1,721,017 research outputs found
An efficient psychovisual threshold technique in image compression
Get PDFNowadays, psychovisual model plays a critical role in an image compression system. The
psychovisual threshold gives visual tolerance to the human visual system by reducing the
amount of frequency image signals. The sensitivity of the human eye can be fully explored
and exploited in the qualitative experiment by describing what has been seen or by image
quality judgment. However, the result of the psychovisual threshold through qualitative
experiment depends on the test condition of the human visual systems and through
repetitive viewing sessions. In a modern image compression, there is a need to provide
some flexibility to obtain quality levels of the image output based on user preferences. The
concept of psychovisual threshold is designed to determine quality levels of the image
output. The psychovisual threshold represents an optimal amount of frequency image
signals in image compression. This research proposes the psychovisual threshold through a
quantitative experiment that can automatically predict an optimal balance between image
quality and compression rate in image compression. The contribution of its frequency
image signals to the image reconstruction will be the primitive of psychovisual threshold in
image compression. It is very challenging to develop a psychovisual threshold from the
contribution of the frequency image signals for each frequency order. In this research, the
psychovisual threshold prescribes the quantization values and bit allocation for image
compression. The psychovisual threshold is the basic primitive prior to generating
quantization tables in image compression. The psychovisual threshold allows a developer
to design adaptively customized quantization values according to his or her target image
quality. The psychovisual threshold is also elementary and primitive for generating a set of
bit allocation for frequency image signals. A set of bit allocation based on psychovisual
threshold assigns the amount of bits for frequency image signals. A set of bit allocation
refers to the psychovisual threshold instead of the quantization process in image
compression. This research investigates the basic understanding of the psychovisual
threshold in image compression. The experimental results provide significant improvement
in the image compression. The psychovisual threshold which is presented as quantization
tables, customized quantization tables and as a set of bit allocation gives a significant
improvement on both of the quality of the image reconstruction and the average bit length
of Huffman code. This research shows that psychovisual threshold is practically the best
measure for optimal frequency image signals on image compression
IMPLEMENTASI SPEECH RECOGNITION BEBERAPA LAMPU PADA SUATU GEDUNG
No full textVoice command digunakan untuk mengontrol beberapa lampu untuk menghidupkan atau memedamkannya
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Image watermarking based on integer wavelet transform-singular value decomposition and variance pixels
Get PDFWith the era of rapid technology in multimedia, the copyright protection is very important to preserve an ownership from multimedia distribution. This paper proposes an image watermarking scheme based on integer wavelet transform and singular value decomposition. Embedding watermark locations are determined by using variance pixels. Selected blocks with the lowest variance values are transformed by Integer Wavelet Transform (IWT) and the LL sub-band of 8×8 transform domain is computed using singular value decomposition. The orthogonal U matrix component of U3,1 and U4,1 are modified using certain rules with considering watermark bits and an optimal threshold. This research reveals the optimal threshold value based on the trade-off between robustness and imperceptibility of watermarked image. The binary watermark is scrambled by Arnold transform before embedding watermark. In order to measure the watermarking performance, the proposed scheme is tested under various attacks. The experimental result indicates that our scheme achieves higher robustness than other scheme under different types of attack
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
An improved hiding information by modifying selected DWT coefficients in video steganography
Get PDFThe rapid expansion of information technology enables users to transfer data or files via the internet in a short time. Steganography is the art of embedding secret information or messages in multimedia data. Video is the most popular medium in steganography to transmit data from sender to receiver. Video has a larger hiding capacity and it provides large redundancy space in video frame sequences. The objective of this research is to embed into the selected video frames based on a new hiding technique with the discrete wavelet transform (DWT). The selected video frames based on scene change detection were chosen for hiding data to minimise the visibility effect on the stego-video. DWT was computed to decompose the selected video frame into sub-bands, the approximation coefficient matrix of two-level DWT was selected to embed the data. The proposed scheme was compared to the existing schemes in terms of imperceptibility. The experimental results showed that the proposed technique achieved high SSIM and PSNR values. The proposed scheme achieved an SSIM value of 0.990 and a PSNR value of 46.09 dB. In addition, the proposed steganography scheme produced good robustness against MPEG-4 compression whereby the message can be fully recognized
Tchebichef image watermarking along the edge using YCoCg-R color space for copyright protection
Get PDFEasy creation and manipulation of digital images present the potential danger of counterfeiting and forgery. Watermarking technique which embeds a watermark into the images can be used to overcome these problems and to provide copyright protection. Digital image watermarking should meet requirements, e.g. maintain image quality, difficult to remove the watermark, quality of watermark extraction, and applicable. This research proposes Tchebichef watermarking along the edge based on YCoCg-R color space. The embedding region is selected by considering the human visual characteristics (HVC) entropy. The selected blocks with minimum of HVC entropy values are transformed by Tchebichef moments. The locations of C(0,1), C(1,0), C(0,2) and C(2,0) of the matrix moment are randomly embedded for each watermark bit. The proposed watermarking scheme produces a good imperceptibility by average SSIM value around 0.98. The watermark recovery has greater resistant after several types of attack than other schemes. © 2019 Institute of Advanced Engineering and Science. All rights reserved
Adaptive scaling factors based on the impact of selected DCT coefficients for image watermarking
No full textImage watermarking technique aims at high imperceptibility of the embedded watermark with minimal distortion in the watermarked images. In frequency-domain, block-based Discrete Cosine Transform (DCT) is a popular method which can be improved by different scaling factors. This paper presents an adaptive scaling factor for selected DCT coefficients in image watermarking. The image blocks that have lowest pixel variances are chosen as the embedding locations. The optimal scaling factors for selected DCT coefficients on the middle frequencies are obtained by finding the best quality of images. The embedding process is performed using the obtained scaling factors. The proposed technique was investigated to verify the robustness and imperceptibility against various image-processing attacks. It is proved that our technique achieves higher robustness against noise addition, filter and compression than the existing schemes in most cases. Our technique produces greater imperceptibility than the existing schemes
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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