Anirban Patra

Bio: Anirban Patra is an academic researcher from JIS College of Engineering. The author has contributed to research in topics: Image processing & Glacier. The author has an hindex of 1, co-authored 7 publications receiving 10 citations.

Multiplexing and encryption of images using phase grating and random phase mask

Abstract: Recent developments in the areas of image processing have guided a new paradigm for research work in communication of images over the internet. Hence, secure storage and retrieval of digital images is a demanding task for future communication services. A scheme to securely store and encrypt multiple images using sinusoidal phase grating is highlighted. In the proposed scheme, images are modulated using different spatial frequencies and orientation angles. In addition, images have been encrypted using random phase mask after filtering. In order to avoid any human intervention in the system, an intensity graph is plotted to retrieve the images by applying inverse Fourier transform. Using this method, it is possible to independently store, encrypt, and retrieve multiple images due to absence of aliasing problem.

Compression of High-Resolution Satellite Images Using Optical Image Processing

Abstract: This chapter presents a novel method for compressing satellite imagery using phase grating to facilitate the optimization of storage space and bandwidth in satellite communication. In this research work, each Satellite image is first modulated with high grating frequency in a fixed orientation. Due to this modulation, three spots (spectrum) have been generated. From these three spots, by applying Inverse Fourier Transform in any one band, we can recover the image. Out of these three spots, one is center spectrum spot and other spots represent two sidebands. Care should be taken during the spot selection is to avoid aliasing effect. At the receiving end, to recover image we use only one spectrum. We have proved that size of the extracted image is less than the original image. In this way, compression of satellite image has been performed. To measure quality of the output images, PSNR value has been calculated and compared this value with previous techniques. As high-resolution satellite image contains a lot of information, therefore to get detail information from extracted image, compression ratio should be as minimum as possible.

Development of UAV Based Glacial Lake Outburst Monitoring System

Abstract: A reliable and accurate glacial monitoring system is being developed with the help of a UAV and high-resolution camera on board. GPS is another major part of system which will help to collect information on glacier melting using reflectrometry principle and complement the information of aerial view of the lake formed due to glacier melting. The information gathered in that way helps the existing human habitat in the vicinity of the glacial lake from Glacial lake Outburst Flood (GLOF), a serious event of North East Indian Himalayan region. The information gathered in that way and generated warning signal are then transmitted to android application which exploits the data for the real time monitoring of the glacier melting as well as increase of area of the lake formed due to glacier melting.

Compression and multiplexing of medical images using optical image processing

Abstract: Developments in optical image processing have guided a new era in teleconferencing for medical research work. As medical images carry a great deal of information, image storage using minimal space, as well as image recovery, are important research areas for telemedicine services. In this chapter, a new scheme for storing and recovering multiple medical images using a sinusoidal amplitude grating has been proposed. In this scheme, all medical images are modulated separately using a high value of spatial grating frequency; in addition, the orientation angle of the grating is varied during this process. As a result of modulation, three spectra for each image are generated. All spectrum planes are added together to form a single spectrum plane. The entire spectrum plane is Gaussian filtered to eliminate speckle noise. For proper optimization of limited storage space and bandwidth requirements, we transmit only a part of the entire spectrum plane. An intensity graph was plotted to find the location of maximum image information. In the intensity graph, an inverse Fourier transform is applied around the peaks to retrieve the transmitted images. To maintain the quality of the output, information loss of images should be kept to the minimum possible during processing. To measure the quality of the output images, a conventional PSNR checking method was applied. The frequency of the grating should be high to avoid any aliasing problem. The main objective of this work is to provide efficient storage and quick transmission of medical images.

A Novel Approach to Compression of Satellite Images Using Butterworth Filtering

Abstract: Compression of images is an important application in the field of satellite image processing as it is suitable for optimization of storage space and sharing over the Internet with optimum bandwidth. In our present communication, a new method for compression of satellite images using Butterworth low-pass filtering has been proposed. Initially, we have transformed the selected satellite image into frequency domain. By varying the cutoff frequency, satellite image has been filtered out. We have used three different cutoff frequencies to extract image from its spectrum. However, to get a reasonably good output, information loss of images should be minimized during compression. To measure the quality of the output images, PSNR values have been calculated in each case.

High-Resolution Monitoring of Himalayan Glacier Dynamics Using Unmanned Aerial Vehicles

Abstract: Himalayan glacier tongues are commonly debris covered and they are an important source of melt water. However, they remain relatively unstudied because of the inaccessibility of the terrain and the difficulties in field work caused by the thick debris mantles. Observations of debris-covered glaciers are therefore scarce and airborne remote sensing may bridge the gap between scarce field observations and coarse resolution space-borne remote sensing. In this study we deploy an Unmanned Aerial Vehicle (UAV) before and after the melt and monsoon season (May and October 2013) over the debris-covered tongue of the Lirung Glacier in Nepal. Based on stereo-imaging and the structure for motion algorithm we derive highly detailed ortho-mosaics and digital elevation models (DEMs), which we geometrically correct using differential GPS observations collected in the field. Based on DEM differencing and manual feature tracking we derive the mass loss and the surface velocity of the glacier at a high spatial accuracy. On average, mass loss is limited and the surface velocity is very small. However, the spatial variability of melt rates is very high, and ice cliffs and supra-glacial ponds show mass losses that can be an order of magnitude higher than the average. We suggest that future research should focus on the interaction between supra-glacial ponds, ice cliffs and englacial hydrology to further understand the dynamics of debris-covered glaciers. Finally, we conclude that UAV deployment has large potential in glaciology and it may revolutionize methods currently applied in studying glacier surface features.

Compression of High-Resolution Satellite Images Using Optical Image Processing

Abstract: This chapter presents a novel method for compressing satellite imagery using phase grating to facilitate the optimization of storage space and bandwidth in satellite communication. In this research work, each Satellite image is first modulated with high grating frequency in a fixed orientation. Due to this modulation, three spots (spectrum) have been generated. From these three spots, by applying Inverse Fourier Transform in any one band, we can recover the image. Out of these three spots, one is center spectrum spot and other spots represent two sidebands. Care should be taken during the spot selection is to avoid aliasing effect. At the receiving end, to recover image we use only one spectrum. We have proved that size of the extracted image is less than the original image. In this way, compression of satellite image has been performed. To measure quality of the output images, PSNR value has been calculated and compared this value with previous techniques. As high-resolution satellite image contains a lot of information, therefore to get detail information from extracted image, compression ratio should be as minimum as possible.

A novel medical image encryption using cyclic coding in COVID-19 pandemic situation

Abstract: During this Covid - 19 pandemic situation, encryption of medical images takes a major role in medical information systems as well as in telemedicine However according to government rule, it is essential to hide the information of the patients Recent development in computer network enhances a lot of facilities in communication area Unfortunately, hackers are misusing this facility and always try to attack on the transmitted information in insecure network For secure transmission of medical images, it is essential to encrypt the information before transmitting In this communication, we are going to present a novel approach of medical image encryption using cyclic coding We have proved that it is quite difficult to decrypt the original information from encoded data in one common mode of attacking- chosen ciphertext attack Moreover, we have proved the effectiveness of the encryption using correlation coefficients Our proposed scheme is suitable for efficient encoding of multiple medical images © 2021 Institute of Physics Publishing All rights reserved

Reduction of polarization loss of five-splitting by T-shaped arrays

Abstract: We present five-splitting equal-intensity laser output based on a T-shaped reflection grating under normal incidence, which is aimed to reduce polarization loss. Although five-splitting has been reported by a single-layer grating, a set of parameters can only be effective for either TE or TM polarization. Both TE and TM polarizations can be operated simultaneously by T-shaped arrays. For only one set of groove profiles, splitting efficiencies of 18.26%/19.32%/18.53% and 18.34%/18.25%/19.56% can be reached in ±2nd / ± 1st / 0th orders for TE and TM polarizations, respectively. Within the incident wavelength of 1544 to 1552 nm and the incident angle range of 0 deg to 0.19 deg, each reflective efficiency for a five-splitting laser output is >17 % . The diffraction mechanism inside the grating can be explained by the modal method. The polarization-independent T-shaped grating with five-splitting laser output presented here should be useful in various laser fields due to good manufacturing tolerance and incident performance.