scholarly journals A Sampling-Agnostic Software Framework for Converting Between Texture Map Representations of Virtual Environments

2017 ◽  
Vol 122 ◽  
Author(s):  
Vinay K Sriram ◽  
Wesley Griffin
Keyword(s):  
Virtual Environments ◽  
Image Quality Assessment ◽  
Sampling Techniques ◽  
Mathematical Framework ◽  
Image Size ◽  
Uniform Sampling ◽  
Octahedral Environment ◽  
Image Width ◽  
Assessment Metrics ◽  
Environment Maps

We have developed a utility to both stitch cube maps into other types of texture maps (equirectangular,dual paraboloid, and octahedral), and stitch those other types back into cube maps. The utility allows for flexibility in the image size of the conversion - the user can specify the desired image width, and the height is computed (cube, paraboloid, and octahedral mappings are square, and spherical maps are generated to have 16:9 aspect ratio). Moreover, the utility is sampling-agnostic, so the user can select whether to use uniform or jittered sampling over the pixels, as well as the number of samples to use per pixel. The rest of this paper discusses the mathematical framework for projecting from cube maps to equirectangular, dual paraboloid, and octahedral environment maps, as well as the mathematical framework for the inverse projections. We also describe two sampling techniques: uniform sampling and correlated multi-jittered sampling. We perform an evaluation of the sampling techniques and a comparative analysis of the different projections using objective image quality assessment metrics.

Image quality assessment metrics by using directional projection

2008 ◽  
Vol 6 (7) ◽  
pp. 491-494 ◽  
Author(s):  
庞建新 Jianxin Pang ◽  
张荣 Rong Zhang ◽  
张晖 Hui Zhang ◽  
黄轩 Xuan Huang ◽  
刘政凯 Zhengkai Liu
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Image Quality Assessment ◽  
Assessment Metrics

scholarly journals QUALITY ASSESSMENT OF PANSHARPENED RASAT AND LANDSAT-8 IMAGES USING SYNTHETIC SENTINEL-2 PANCHROMATIC IMAGE

2021 ◽  
Vol XLVI-4/W5-2021 ◽  
pp. 231-234
Author(s):  
M. A. Günen
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Spatial Resolution ◽  
Image Quality Assessment ◽  
Reference Image ◽  
Landsat 8 ◽  
Data Generation ◽  
Gis Applications ◽  
Assessment Metrics ◽  
Sentinel 2

Abstract. Technical and physical limitations often do not allow images to be acquired with high spatial and spectral resolution. Pansharpened images obtained by fusing high spatial resolution panchromatic images and multi-spectral images are widely used in GIS applications. In this study, it is aimed to increase the spatial resolution of the RASAT and Landsat-8 multispectral satellite images with synthetic Sentinel-2 panchromatic data. Six different pansharpening methods were used to test the success of the synthetic panchromatic data generation method using dataset with two different land use/land cover properties. Seven full reference image quality assessment metrics and two referenceless image quality assessment metrics were used to perform quantitative comparison.

Image Quality Assessment Based on Invariant Moments Similarity

2012 ◽  
Vol 546-547 ◽  
pp. 565-569
Author(s):  
Mei Wang ◽  
E Ye Wang ◽  
Guo Hua Pan
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Image Quality Assessment ◽  
Experimental Result ◽  
Original Image ◽  
Image Size ◽  
Invariant Moment ◽  
Invariant Moments ◽  
Computing Complexity ◽  
Better Than

To resolve the problems of the image quality assessment issue and the algorithm adaptability for different image size and deformation, this paper proposes a image quality assessment algorithm based on Invariant Moments Similarity. Firstly, Hu invariant moments values of original image and evaluated image are computed. Secondly the invariant moments distance is completed between original image and evaluated image. At last, the method assess the restoration image quality depend on the invariant moment distance. The experimental result shows that the algorithm result is better than MSE, PSNR, SSIM for the same-size images. And the algorithm based on invariant moment similarity can evaluate different image-size and deformation images with low computing-complexity. The assessment experimental result for difference actual images certifies the algorithm effectiveness.

scholarly journals Social distance: a comparison between the screen and virtual environments

2021 ◽  
Author(s):  
Marcos Emanoel Pereira ◽  
Elza Maria Techio ◽  
José Luís Álvaro ◽  
Benvindo Maloa ◽  
Carina Feitosa ◽  
...  
Keyword(s):  
Data Collection ◽  
Response Time ◽  
Virtual Environments ◽  
Virtual Environment ◽  
Social Distance ◽  
Skin Color ◽  
Social Groups ◽  
Image Size ◽  
Indirect Measure ◽  
Indirect Measures

Social distance is one of the indicators of intergroup relations. It expresses the degree of intimacy, proximity or distance in relation to the members of specific social groups, making the concept an indirect form of referring to prejudice. The present study described in this article aims to evaluate the protocol for the use of an indirect measure of social distance, implemented by computers and specialized devices. We sought to assess the potential of the technique of virtual reality as a criterion for estimating social distance by comparing the results obtained in the virtual environment with the correlated measures obtained in a computer screen. This is an experimental study, developed to evaluate the pleasantness of four photographs and the registry of two classes of indirect measures. Social distance was chosen to evaluate the photographs and the response time was used to choose the estimate, in two modalities of data collection, one in a screen environment and the other in the virtual environment, in Brazil and Mozambique. A total of 150 university students participated in the study, 87 from Brazil and 61 from Mozambique. In the study, we show that the estimate for social distance is more associated with the response time than the attractiveness of the image, regardless of the country. When we introduce in the predictive models the variables sex and skin color of the individuals portrayed in the photographs, we note that the models obtained in the virtual environment present better indicators than those obtained in the screen, except for the predictive model for the evaluation of the distance of the Black woman portrait. The response time proved to be much more central in the model than the attractiveness of the image. In the screen environment, the increase in the image size was connected to the greater amount of time spent in decision-making while in the virtual environment the distancing from the image was connected to a greater amount of time spent making a decision. The country of origin had little influence over the final models. In conclusion, we may highlight that the effects of social distance, the response time and the attractiveness of the image were greater in the virtual environment, which inspires us to highlight the importance of using more sophisticated data collection procedures through the use of information technology.

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