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Hiding Media Data via Shaders: Enabling Private Sharing in the Clouds
Published in Kaikai Liu, Xiaolin Li, Mobile SmartLife via Sensing, Localization, and Cloud Ecosystems, 2017
Fig. 11.3 shows our designed secure media sharing process to open social media channels. We leverage the image key in addition to the normal key for better security. To meet the design objective of easy-to-use and low-complexity computation, we integrate our proposed privacy-preserving techniques into one customized image filter. The image filter works in the raw image domain and does not require image format compliance. A highly integrated block could simplify the integration process to existing code. To improve the efficiency for the pixel-wise computation in our approach, we design and implement this customized image filter in the GPU via the OpenGL Shader. Shader is a program designed to run on some stage of a graphics processor, and written in the OpenGL Shading Language. We utilize the Fragment Shaders in the OpenGL rendering pipeline (after Rasterizer) for the pixel manipulation required in our proposed algorithm. The size covered by a fragment is related to the pixel area. Thus, the computationally intensive pixel-by-pixel operation could be converted to fragment processing with highly paralleled implementation in GPU. The reason that we utilize normalization and block-based processing in algorithm design is to fit the GPU Shader processing framework for high computation efficiency.
SSVEP-based brain–computer interface for music using a low-density EEG system
Published in Assistive Technology, 2022
Satvik Venkatesh, Eduardo Reck Miranda, Edward Braund
In order to utilize hardware-accelerated rendering and vertical synchronization (VSync), the visual stimulus is implemented with the help of Open Graphics Library (OpenGL). Vertex shader and fragment shader programs were written in OpenGL shading language (GLSL). The vertex shader specifies the coordinates of the flashing squares and the fragment shader varies the luminance of the region. The luminance is varied by Equation (1) with the help of sinusoidal stimulation (Manyakov et al., 2013).