Channel (digital image)

About: Channel (digital image) is a research topic. Over the lifetime, 7211 publications have been published within this topic receiving 69974 citations.

Rough-Set-Based Color Channel Selection

Abstract: Color channel selection is essential for accurate segmentation of sky and clouds in images obtained from ground-based sky cameras. Most prior works in cloud segmentation use threshold-based methods on color channels selected in an ad hoc manner. In this letter, we propose the use of rough sets for color channel selection in visible-light images. Our proposed approach assesses color channels with respect to their contribution for segmentation and identifies the most effective ones.

A cryptographic model for better information security

Abstract: In this study, a novel cryptographic model that uses coupled map lattice is proposed for securing image. It incorporates mixing based on randomly generated secret key, sub-keys based substitution, confusion algorithm and coupled map lattice based diffusion process to enrich the security, sensitivity and robustness of the model. The control parameters of coupled map lattice and initial condition of chaotic systems are deduced using externally generated random secret key of 280-bit length. To make the encryption process more dependent on confusion and more sensitive to the encryption key, pixels of a channel are XOR-ed with pixels of other channel with an intelligent mix of sub-keys. Finally, the diffusion model based on coupled map lattice, binds the pixels in a way such that a single-bit change is reflected into a large number of pixels in the cipher image. Resistance to various kinds of attacks like plain text, brute force and statistical attacks are the important features observed in the proposed cryptographic model. Several studies related to correlation coefficients, histogram, anti-noise attacks, plain text analysis, NPCR, key sensitivity, UACI and key space analysis were carried out and corresponding results are given in detail. The simulation results yield an average NPCR score to be about 99.63% and UACI value 33.46%. A number of analysis performed and mentioned here, suggests the proposed model a potential candidate for image encryption application.

Fast Single Image Defogging With Robust Sky Detection

Abstract: Haze is a source of unreliability for computer vision applications in outdoor scenarios, and it is usually caused by atmospheric conditions. The Dark Channel Prior (DCP) has shown remarkable results in image defogging with three main limitations: 1) high time-consumption, 2) artifact generation, and 3) sky-region over-saturation. Therefore, current work has focused on improving processing time without losing restoration quality and avoiding image artifacts during image defogging. Hence in this research, a novel methodology based on depth approximations through DCP, local Shannon entropy, and Fast Guided Filter is proposed for reducing artifacts and improving image recovery on sky regions with low computation time. The proposed-method performance is assessed using more than 500 images from three datasets: Hybrid Subjective Testing Set from Realistic Single Image Dehazing (HSTS-RESIDE), the Synthetic Objective Testing Set from RESIDE (SOTS-RESIDE) and the HazeRD. Experimental results demonstrate that the proposed approach has an outstanding performance over state-of-the-art methods in reviewed literature, which is validated qualitatively and quantitatively through Peak Signal-to-Noise Ratio (PSNR), Naturalness Image Quality Evaluator (NIQE) and Structural SIMilarity (SSIM) index on retrieved images, considering different visual ranges, under distinct illumination and contrast conditions. Analyzing images with various resolutions, the method proposed in this work shows the lowest processing time under similar software and hardware conditions.

Single-channel color image encryption algorithm based on fractional Hartley transform and vector operation

Abstract: A single-channel color image encryption algorithm is proposed by combining fractional Hartley transform (FRHT) with vector operation. The original color image is decomposed into RGB components and the G and B components are encrypted into two phase-only masks ? G and ? B with vector operation, respectively. The R, ? G and ? B are transformed by FRHT and vector operation twice to obtain amplitude, random phase and decryption phase key. The new amplitude combined with the random phase is transformed by FRHT once more and then the result is scrambled by the chaotic scrambling to strengthen the security of the algorithm. The private phase key is dependent on the original image, which makes the proposed encryption algorithm more secure than the linear color image encryption algorithm based on the double random phase encoding in FRHT. Simulation results demonstrate the security and effectiveness of the proposed algorithm.

Color machine vision system for process control in the ceramics industry

Abstract: This paper is focused on the design of a machine vision system to solve a problem found in the manufacturing process of high quality polished porcelain tiles. This consists of sorting the tiles according to the criteria 'same appearance to the human eye' or in other words, by color and visual texture. In 1994 this problem was tackled and led to a prototype which became fully operational at production scale in a manufacturing plant, named Porcelanatto, S.A. The system has evolved and has been adapted to meet the particular needs of this manufacturing company. Among the main issues that have been improved, it is worth pointing out: (1) improvement to discern subtle variations in color or texture, which are the main features of the visual appearance; (2) inspection time reduction, as a result of algorithm optimization and the increasing computing power. Thus, 100 percent of the production can be inspected, reaching a maximum of 120 tiles/sec.; (3) adaptation to the different types and models of tiles manufactured. The tiles vary not only in their visible patterns but also in dimensions, formats, thickness and allowances. In this sense, one major problem has been reaching an optimal compromise: The system must be sensitive enough to discern subtle variations in color, but at the same time insensitive thickness variations in the tiles. The following parts have been used to build the system: RGB color line scan camera, 12 bits per channel, PCI frame grabber, PC, fiber optic based illumination and the algorithm which will be explained in section 4.