Color correction and enhancement for underwater images is challenging due to attenuation and scattering. The underwater images often have low visibility and suffer from color bias. This paper presents a novel color correction method based on color filter array (CFA) and an enhancement method based on Retinex with dense pixels and adaptive linear histogram transformation for degraded color-biased underwater images. For any digital image in the RGB space, which is captured by digital camera with CFA, their RGB values are dependent and coupled because of the interpolation process. So we try to compensate red channel attenuation of underwater degraded images from the green channel and blue channel. Retinex model has been widely used to efficiently handle low brightness and blurred images. The McCann Retinex (MR) method selects a spiral path for pixel comparison to estimate illumination. However, the simple path selection doesn’t include global light dark relationship of the whole image. So we design a scheme to gain much well-distributed and denser pixels to obtain more precise intensity of illumination. Besides, we design a piecewise linear function for histogram transform, which is adaptive to the whole RGB value. Experiments on a large number of underwater degraded images show that, the processed images by our method have clearer details and uniform visual effect for all channels in RGB color space and our method can also obtain good performance metrics.

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Color Correction Based on CFA and Enhancement Based on Retinex With Dense Pixels for Underwater Images

Achieving subjective and objective quality assessment of underwater images is of high significance in underwater visual perception and image/video processing. However, the development of underwater image quality assessment (UIQA) is limited for the lack of publicly available underwater image datasets with human subjective scores and reliable objective UIQA metrics. To address this issue, we establish a large-scale underwater image dataset, dubbed UID2021, for evaluating no-reference (NR) UIQA metrics. The constructed dataset contains 60 multiply degraded underwater images collected from various sources, covering six common underwater scenes (i.e., bluish scene, blue-green scene, greenish scene, hazy scene, low-light scene, and turbid scene), and their corresponding 900 quality improved versions are generated by employing 15 state-of-the-art underwater image enhancement and restoration algorithms. Mean opinion scores with 52 observers for each image of UID2021 are also obtained by using the pairwise comparison sorting method. Both in-air and underwater-specific NR IQA algorithms are tested on our constructed dataset to fairly compare their performance and analyze their strengths and weaknesses. Our proposed UID2021 dataset enables ones to evaluate NR UIQA algorithms comprehensively and paves the way for further research on UIQA. The dataset is available at https://github.com/Hou-Guojia/UID2021.

UID2021: An Underwater Image Dataset for Evaluation of No-Reference Quality Assessment Metrics

Cryptography and Steganography are two commonly used techniques in modern era for ensuring confidential and private communication. These techniques complete each other offering multiple layers of safety, enhancing digital information security. In this paper we analyze Smartsteg, which is a project that implements cryptography combined with steganography on mobile devices that run Android and Windows. We evaluate the performance of this project in terms of: interoperability, security, payload capacity, speed and robustness against steganalysis.

Testing methods for the efficiency of modern steganography solutions for mobile platforms

Authentication of any system means providing a security to that system. Securing confidential information on the mobile platforms has been becoming a typical issue for the specialists. One of the authentication techniques is a textual password based. This type of textual password commonly follows an encryption algorithm to provide security. This techniques has some limitations and drawbacks. When users choose meaningful words from dictionaries, by using brute force attacks, it makes textual passwords vulnerable to dictionary and easy to break. To overcome the drawbacks, a new authenticate technique is proposed in this paper in order to provide for more security authentication system. In this paper the textual password will be hidden in an image using steganography technique. All data and critical information like passwords are stored in encrypted manner used image as carrier so it's difficult for brute force attack to crack it. Steganography is used to hide secret information onside some carrier. The most basic and important image steganography technique is Least Significant Bit (LSB) embedding technique. In this technique, data can be hidden in the least significant bits of the cover image and the human eye would be unable to notice the hidden image in the cover file. LSB steganography is combined with AES cryptography to hide textual password, in order to provide high level security on authentication system that run under Android.

Stegano-image as a digital signature to improve security authentication system in mobile computing

Enhanced visual perception for underwater images based on multistage generative adversarial network

Due to the scattered lighting and light absorbed conditions, the underwater images frequently suffered from the low contrast as well as color distortion. As underwater images with the different color tones are captured under different light conditions, it is difficult to perform restoration and enhancement of such images. There are number of conventional methods reported to improve the quality of underwater images, however they constantly performs poor. In this paper, we propose a novel underwater image restoration and enhancement algorithm. We proposed the novel modified depth estimation approach for underwater images based on image blurriness as well as light absorption. To improve the processing speed as well as image quality we proposed novel image blurriness estimation approach in first we performed the image normalization and double precision conversion to improve the processing speed, then apply the edge-stopping pyramid technique rather than Gaussian filtering to improve image quality. The proposed approach is simulated and evaluated against the state-of-art methods in terms of processing time, PSNR, SSIM etc.

Underwater Image Restoration Based on Light Absorption

Real time implementation of Steganographic algorithm along with encryption is used to achieve secure data flow across Android mobiles. In this paper, pixel value differencing (PVD) technique one of the steganographic algorithm with AES encryption are implemented using JAVA TM on android platform to achieve high level security for real time multimedia messaging service (MMS) system. One of the important concerns in any communication system is the security of the data transmission from eavesdropper. To overcome this security problem, the most effective technique is the steganography. Steganography is used to hide secret information onside some carrier. Image is taken as a carrier file to hide secret information (text, image, audio). To add more security, encryption is also done on the secret file which will be hidden inside MMS. The Pixel Value Differencing (PVD) technique is used to hide secret information (text, image, audio). Different sizes of secret images are considered keeping the fixed size of cover image and the calculations have been done for MSE and PSNR of image in MATLAB. Later, the results of the PVD are compared with the LSB technique. Encryption and Steganographic algorithms are ported on Sony Xperia M mobile device with Android version 4.3. Keywords – Android Platform, Encryption, LSB, PVD, MMS, MSE, PSNR, Security, Steganography.

Android Application Development for Secure Data Transmission using Steganography

The recent technology in digital cameras uses single CCD or CMOS sensors as a substitute to three separate RGB sensors Color camera consists of single CCD or CMOS sensor with an overlaid Color Filter Array (CFA) This paper proposes a novel approach of CFA demosaicing In proposed approach, bilinear interpolation with sharpening filter is used for CFA demosaicing The proposed work tested on Virtex 5 FPGA in real time mode as well as on true color test image database Xilinx System Generator (XSG) has been used for system modeling and design implemented on target device FPGA The results of proposed FPGA based work improved than software based simple bilinear interpolation, edge directed interpolation and adaptive color plane interpolation methods and comparative to modified adaptive color plane interpolation method The proposed approach has low computational complexity and high image processing speed; hence the design can be implemented in real time low cost embedded system applications

Modified demosaicing scheme on FPGA using Xilinx System Generator

Video compression is a key enabling technology for multimedia communication. The need for high-quality video processing in multimedia products is increasing, leading to enhancement in coding techniques. In future, multimedia systems require efficient video coding algorithms that provide high and efficient compression. The H.264 is one of the latest coding standards that provide high compression efficiency and network friendly representation compare to previous standards. In this paper, we present an architecture for Context-Based Adaptive Binary Arithmetic coding (CABAC) decoder which is used in H.264 as entropy decoding. CABAC gives higher compression efficiency by bringing higher implementation cost and complexity. In this work, we are focusing on designing an efficient and fast hardware and software co-design for CABAC which can be useful for the real-time application. A complex part of CABAC is design over FPGA hardware and remaining parts are on processing system (PS). For this work, we are using zynq-7000 based Zedboard which consists two parts one is Programing Logic (FPGA) and second is Processing system (Arm Cortex-9). We create an IP for a part of CABAC which can communicate with PS by AXI bus.

Manisha R. Ingle

Papers

Underwater Image Restoration Based on Light Absorption

Android Application Development for Secure Data Transmission using Steganography

Modified demosaicing scheme on FPGA using Xilinx System Generator

Hardware software co-design for CABAC entropy decoder