Li Fangfang

KhAI - Aerospace university · Information-Communication Technologies

This chapter contains the results obtained during execution of Ukrainian-Polish Project in 2021 intended on design of methods and means for processing grayscale and multichannel images and video using visual quality metrics. The combined metrics have been designed and tested for remote sensing images as well as stitched panoramic images. Examples o...

In this chapter, a task of providing a desired compression ratio (CR) is considered for lossy compression of color images by better portable graphics (BPG) encoder. This encoder is characterized by many benefits compared to other modern encoders according to rate-distortion performance and some other important facilities. However, the produced CR f...

Remote sensing image compression plays an important role in Earth observation applications. Lossy compression techniques are efficient means to reduce the size of images, although the distortions are unavoidable. Consequently, the image quality should be controlled carefully. This paper discusses this topic with its application to JPEG. Using visua...

The chapter considers some aspects of processing multichannel remote sensing images using trained neural networks

This paper presents an investigation into the visually lossless JPEG compression which provides maximum compression ratio applied before the resulting compressed image appears distorted. The research was conducted using two publicly available databases with the results of just noticeable difference tests. It has been shown that using visually lossl...

In this paper, we consider a task of providing a desired compression ratio (CR) in lossy compression of color images by better portable graphics (BPG) encoder. The problem consists in the fact that this encoder, on the one hand, produces certain benefits compared to other modern image compression techniques in the sense of better quality for the sa...

Single and three-channel images are widely used in numerous applications. Due to the increasing volume of such data, they must be compressed where lossy compression offers more opportunities. Usually, it is supposed that, for a given image, a larger compression ratio leads to worse quality of the compressed image according to all quality metrics. T...

This is the presentation given at 2022 International Conference on the Cooperation and Integration and Integration of Industry, Eduation, Research and Application (Nanchang, China)

This paper deals with lossy compression of grayscale and color images. A traditional assumption for any compression technique and any image is that a higher compression ratio leads to worse quality of any compressed image according to any quality metric, either standard one as MSE or PSNR or a visual quality metric. Meanwhile, it has been discovere...

It is well known that image processing efficiency considerably depends on image properties. Among operations of image processing, we mean quality assessment, noise characteristic estimation, lossless and lossy compression, denoising, etc. In many papers, such terms as "image complexity", "rich image content", "highly textural image" are used. Their...

Classification accuracy of remote sensing data depends on many factors including level of distortions if lossy compression is applied to original data. However, it is difficult to predict what compression ratio or characteristics of distortions have to be provided in order to ensure classification accuracy reduction due to lossy compression is appr...

This paper deals with providing the desired quality in the Better Portable Graphics (BPG)-based lossy compression of color and three-channel remote sensing (RS) images. Quality is described by the Mean Deviation Similarity Index (MDSI), which is proven to be one of the best metrics for characterizing compressed image quality due to its high convent...

Better Portable Graphics (BPG), which is based on the High Efficiency Video Coding (HEVC), outperforms many other traditional lossy compression methods in terms of compression ratio and visual quality expressed in standard metrics. It might be necessary to provide a desired visual quality in some conditions where visual perception is of prime impor...

Lossy compression has been widely used in various applications due to its variable compression ratio. However, distortions are introduced unavoidably, and this decreases the image quality. Therefore, it is often required to control the quality of the compressed images. A two-step method has been proposed recently to provide the desired visual quali...

It is a common task in image lossy compression to provide a reasonable trade-off between a desired compression ratio (as large as possible) and an appropriate (preset according to a chosen metric) quality. Recently, a Better Portable Graphics (BPG) coder has been proposed that might become a new standard. A quality parameter Q is used in it to vary...

The development of remote sensing technology leads to a huge number of acquired images needed to be stored and/or transferred. Lossy compression is an essential mean to reduce the image size and, thus, to improve the efficiency of storing and transferring. Meanwhile, a certain quality (including visual quality) must be provided in lossy compression...

Lossy compression plays a vital role in modern digital image processing for producing a high compression ratio. However, distortion is unavoidable, which affects further image processing and must be handled with care. Providing a desired visual quality is an efficient approach for reaching a trade-off between introduced distortions and compression...

This is presentation of report done at seminar in Poland

Presentation for the exchange visit with Poland

In this paper, we consider a problem of lossy compression of three-channel or color images with application to remote sensing. The main task of such a compression is to provide a trade-off between compression ratio and quality of compressed data that should be appropriate for solving the basic tasks as classification of sensed terrains, object dete...

image compression is getting more importance for numerous applications like high resolution cameras, computer vision devices, portable instruments, remote sensing imagers, etc. To be useful for practice, an image compression method has to meet several requirements including high compression rate and visual quality, speed of compression and decompre...

Wavelet-based image compression techniques, in particular, SPIHT have an obvious advantage of providing a desired compression ratio. However, for a given compression ratio, quality can vary in wide limits and it can be unsatisfactory for a given image, especially if it is highly textural. Then, one needs to choose and set another compression ratio...

BPG is often treated nowadays as an alternative to JPEG. There are quite impressive comparisons of their performance (see http://xooyoozoo.github.io/yolo-octo-bugfixes/#endeavor-and-columbia&jpg=s&bpg=s). In BPG, the parameter that controls compression (allows varying compression quality and compression ratio) is Q. However, the use of the same Q d...

Lossy compression is widely used to decrease the size of multichannel remote sensing data. Alongside this positive effect, lossy compression may lead to a negative outcome as making worse image classification. Thus, if possible, lossy compression should be carried out carefully, controlling the quality of compressed images. In this paper, a depende...

Providing a desired visual quality of lossy compression is an important and interesting research direction, it has been studied intensively in recent years. Its purpose is to guarantee that lossy compression will not affect further image processing efficiency due to too large loss of information while providing a relatively large compression ratio...

Flexible quantum dot light emitting diodes have attracted widespread attention due to their many advantages such as low cost, color tunability, and high luminance effciency. Among flexible electrodes, copper nanowires have attracted much attention due to their high electrical conductivity, simple fabrication process, and low cost. However, the oxid...

Improving the hole carrier mobility of organic hole-transporting materials is critical for the development of advanced quantum dot light-emitting diodes (QLEDs). Here, a simple method is reported for enhancing the hole-charge mobility in poly(9-vinylcarbazole), PVK. Doping of the PVK using the molecular Lewis acid tris(pentafluorophenyl)borane as a...

Low hole mobility and poor film quality always result in poor performance of quantum dot light-emitting diodes (QLEDs). As a p-type dopant into the hole-transport layer (HTL) of the poly[N,N‘-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine](poly-TPD), B(C6F5)3 is used in hole mobility and film quality improvement for QLEDs. The results show that the h...

Image information technology has become an important perception technology considering the task of providing lossy image compression with the desired quality using certain encoders Recent researches have shown that the use of a two-step method can perform the compression in a very simple manner and with reduced compression time under the premise of...

A task of classification of multichannel remote sensing images compressed in a lossy manner is considered. It is recalled that lossy compression usually leads to reduction of classification accuracy both in aggregate and for particular classes. Distortions due to compression are characterized by visual quality metric desired values of which can be...

considered. Quality is mainly characterized by the peak signal-to-noise ratio (PSNR) but visual quality metrics are briefly studied as well. Potentially, a two-step approach can be used to carry out a compression with providing the desired quality in a quite simple way and with a reduced compression time. However, the two-step approach can run into...

considered. Quality is mainly characterized by the peak signal-to-noise ratio (PSNR) but visual quality metrics are briefly studied as well. Potentially, a two-step approach can be used to carry out a compression with providing the desired quality in a quite simple way and with a reduced compression time. However, the two-step approach can run into...

We report a high-efficient green CdSe/ZnS quantum-dot light-emitting diode (QLED) using 2,2’,7,7’-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9’-Spirobifluorene (Spiro-OMeTAD) as an electron buffer layer. The high lowest unoccupied molecular orbital level of Spiro-OMeTAD suppresses the electron transfer and promotes the charge balance. The external qu...

The structural stability, electronic structures, mechanical properties and Debye temperature of W-TM (TM = Cr, Cu, Fe, Mn, Mo and Ni, respectively) alloys have been investigated by first principles method. The lattice constant, cell volume, formation energy and cohesive energy of W-TM alloys are calculated. W-TM alloys still maintain bcc lattice, a...

The emission layer (EML) of nanorods is doped with p-type 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) to improve performances of quantum dot light-emitting diodes. The hole-electron balance has been found to enhance in these devices. This has been attributed to increase in hole transport and decrease in electron transport. F4TCNQ...