eft ventricular mechanical dysfunction estimated by ejection fraction (EF) and complex ventricular premature beats are independent prognostic predictors in patients with idiopathic dilated cardiomyopathy (IDCM). [1][2][3][4] From the histological viewpoint, it is likely that myocardial fiber degeneration and fibrotic replacement, resulting in the disruption of cell-to-cell connections, 5,6 would not only reduce left ventricular mechanical performance but would also produce electrophysiological abnormalities, such as disruptions of the depolarization wavefront and regional conduction delays, that would provide an appropriate substrate for arrhythmogenicity. The incidence of sudden cardiac death presumably due to fatal ventricular tachyarrhythmia increases with the progression of heart failure and the reduction of the left ventricular EF, 7,8 which suggests that the potential for fatal ventricular arrhythmia due to electrophysiological derangement may progress insidiously with left ventricular mechanical dysfunction, whether or not there is a history of symptomatic malignant ventricular tachycardia.Disruptions of the depolarization wavefront and regional conduction delays, which could provide a substrate for a reentrant pathway and subsequent ventricular tachyarrhythmia, produce fine, fragmented signals in the QRS complex Japanese Circulation Journal Vol.63, January 1999 of the electrocardiogram (ECG). 9-11 Fine, delayed, fragmented signals in the terminal QRS/ST segment of the signal-averaged ECG, which are defined as late potentials, have been related to slowly activated tissue responsible for sustained ventricular arrhythmia and sudden cardiac death. However, late potentials are only some of the pathological signals that extend into the terminal QRS/ST segment; others might be hidden in the QRS complex, 12 and the presence of late potentials has not been thought to indicate a decrease in the left ventricular ejection fraction in patients with IDCM. 1,9,13,14 Wavelet analysis is a new time-frequency technique that enables the detection and localization of small, transient signals in the QRS complex. [15][16][17][18][19][20][21][22] Thus, this study was conducted to clarify whether fine, fragmented signals in the QRS complex detected by the wavelet transform are related to the severity of ventricular arrhythmia, cardiac mortality, the appearance of late potentials, and left ventricular mechanical dysfunction in patients with IDCM. For this purpose, we modified the original equation of wavelet analysis for a quantification of fine fragmented signals, and the relations of 4 quantitative indices; that is, the number and the density of local maxima, and the duration and the root mean square amplitude of wavelet transform, derived from wavelet transform to these issues, were evaluated. Methods SubjectsThis study involved 26 Japanese subjects with IDCM, identified according to criteria of the World Health Organization. 23 All were in sinus rhythm without bundle branch or fascicular block, or any symptoms at rest. The J...
Quantitatively evaluating the psychological and perceptual effects of objects is an important issue, but is difficult. In cognitive studies, the psychological potential field (PPF), which represents psychological intensities in vision and can be calculated by applying computational algorithms to digital images, may help with this issue. Although studies have reported using the PPF to evaluate psychological effects, such as impressions, detailed investigations on how the PPF represents psychological perception and its limitations have not yet been performed. Another relevant tool is the fixation map, which visualizes human eye fixations; this map is generated from actual measurements acquired by eye-tracking and does not represent psychological effects directly. Although the PPF and the fixation map are based on visual imaging, they have never been compared. In this paper, we do so for the first time, using psychological and perceptual properties of line-drawing images. The results demonstrate the difference between these methods, including their representation of different properties with respect to visual perception. Moreover, the similarity between the two methods highlights the possibility of assessing perceptual phenomena such as categorization and cognition of objects based on human vision.
:Field of Visual Perception (FVP) has been attracted as a method for quantitative evaluation of impression. In recently, FVP for digital images has been proposed, and the effectiveness has been confirmed. However, FVP has not been applied widely on the field of image processing by two reasons: (1) the calculation cost is too high, and (2) only calculation model for binary images has been established and it cannot be applied to grayscale images. This paper first proposes an acceleration method for increasing practicality. Next, instead of grayscale image, we verify the correctness and the effectiveness of applying FVP to halftone image, which is binary image converted from grayscale image without discomfort. The experimental results showed that the calculation cost decreased to 0.01% at least. Moreover, the results of applying FVP to halftone images showed both of the difficulties and the potentialities for evaluating impression.
Most people are concerned about their appearance, and the easiest way to change the appearance is to change the hairstyle. However, except for professional hairstylists, it is difficult to objectively judge which hairstyle suits them. Currently, oval faces are generally said to be the ideal facial shape in terms of suitability to various hairstyles. Meanwhile, field of visual perception (FVP), proposed recently in the field of cognitive science, has attracted attention as a model to represent the visual perception phenomenon. Moreover, a computation model for digital images has been proposed, and it is expected to be used in quantitative evaluation of sensibility and sensitivity called "kansei." Quantitative evaluation of "goodness of patterns" and "strength of impressions" by evaluating distributions of the field has been reported. However, it is unknown whether the evaluation method can be generalized for use in various subjects, because it has been applied only to some research subjects, such as characters, text, and simple graphics. In this study, for the first time, we apply FVP to facial images with various hairstyles and verify whether it has the potential of evaluating impressions of female faces. Specifically, we verify whether the impressions of facial images that combine various facial shapes and female hairstyles can be represented using FVP. We prepare many combinational images of facial shapes and hairstyles and conduct a psychological experiment to evaluate their impressions. Moreover, we compute the FVP of each image and propose a novel evaluation method by analyzing the distributions. The conventional and proposed evaluation values correlated to the psychological evaluation values after normalization, and demonstrated the effectiveness of the FVP as an image feature quantity to evaluate faces. key words: hairstyle, facial shape, field of visual perception, kansei, objective evaluation Naoyuki Awano received the BIS, MIS, and
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