arXiv subjects

Jan K. Argasinski

Publications and source records attributed to Jan K. Argasinski.

3 recordsLinked to original sources

arXiv2026

A BEMD-Based Quaternion Filtering Approach Sharp-to-Soft Kernel CT Image Conversion

The quality of computed tomography (CT) images is significantly affected by the selection of reconstruction kernels: sharp kernels improve spatial resolution but increase noise, whereas soft kernels diminish noise at the expense of edge clarity. This study presents an innovative enhancement framework utilising Bidimensional Empirical Mode Decomposition in conjunction with Quaternion Bilateral Filtering (BEMD--QBF) to convert sharp-kernel CT images into representations resembling soft-kernels, while maintaining critical anatomical structures. The technique disaggregates each image into intrinsic mode functions via BEMD and analyzes them inside a cohesive quaternion framework to attain efficient noise reduction and structural integrity. The proposed methodology is evaluated using several reconstruction kernels (B50, B46, B41, B36, B35, B31) and compared with recognised filtering strategies, including Non-Local Means, Anisotropic Diffusion, Bilateral Filtering, and Quaternion Bilateral Filtering. Quantitative evaluations of the Structural Similarity Index (SSIM) and Peak Signal-to-Noise Ratio (PSNR) indicate that BEMD-QBF consistently attains superior structural fidelity and competitive noise reduction across all evaluated kernels. The results underscore the efficacy of the proposed strategy as a viable approach to enhancing post-reconstruction CT images, yielding superior image quality without requiring access to raw projection data.

cs.CV↗

arXiv2026

Decomposition-Guided Curvelet Thresholding for Sharp-to-Soft CT Kernel Conversion

Image denoising is a crucial task in image processing, focused on improving image quality by minimizing noise while maintaining essential structural elements. This study presents a hybrid denoising framework that combines several decomposition techniques, including empirical mode decomposition (EMD), variational mode decomposition (VMD), multichannel EMD (MEMD), and bidimensional EMD (BEMD), with curvelet transform thresholding. Each decomposition mode undergoes processing through both soft and hard thresholding, and the denoised modes are combined to rebuild the final image. Comprehensive evaluations of standard CT image datasets reconstructed with various kernels (B50, B46, B41, B36) reveal substantial enhancements in denoising efficacy. VMD consistently achieves the highest peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM), signifying exceptional noise reduction and feature preservation. The study analyses the trade-offs between soft and hard thresholding: soft thresholding maintains intricate visual details, whilst harsh thresholding provides enhanced noise reduction. The suggested method surpasses traditional techniques in both reference and non-reference quality criteria, indicating its potential for broader application in medical imaging and future incorporation with adaptive thresholding algorithms.

cs.CV↗

arXiv2026

The machine can say it but cannot hear it. Designed affective patterns and the expressive-sensing asymmetry in human-machine communication

Affect-adaptive systems increasingly act as communicators that sense a user's emotion and respond with events meant to change it, closing an affective loop. This vision assumes both that a machine's affective messages are received and that the bodily channel it monitors carries an intelligible reply-assumptions rarely tested together. In a within-subjects virtual-reality study (N = 20), an autonomous system delivered six empirically derived affective patterns-scripted emotional events distilled from 104 practitioners' (first responders') critical incidents-while we recorded the human reply across felt emotion, felt arousal, and autonomic (electrodermal and cardiac) activity. Acting only as an author of designed messages, the machine reliably evoked strong, differentiated emotions: valence fell sharply for every pattern (|dz| = 1.1-1.7), and the patterns produced distinguishable, individually classifiable signatures of anger, fear, and sadness, functioning as a vocabulary of machine-to-human affective messages. Yet the channel the machine would read stayed largely silent. Self-reported arousal did not change, with Bayesian and equivalence evidence for no effect; sympathetic and cardiac arousal moved only for the most perceptually salient events, not for the messages experienced as most powerful; and within individuals, felt valence was decoupled from both bodily registers. This valence-arousal dissociation reveals an expressive-sensing asymmetry: machine agency extends to expression but not perception, and closed-loop designs regulate on a variable their messages neither reliably move nor are legible in. We draw out implications for theories of machine agency and for affect-adaptive design.

cs.HC↗