May 27th, 2014
March 19th, 2014
This master’s thesis by Markus Konrad analyzes the potentials of GPGPU on mobile devices such as smartphones or tablets. The question was, if and how the GPU on such devices can be used to speed up certain algorithms especially in the fields of image processing. GPU computing technologies such as OpenCL, OpenGL shaders, and Android RenderScript are assessed in the thesis. The abstract reads as follows:
This thesis studies how certain popular algorithms in the field of image and audio processing can be accelerated on mobile devices by means of parallel execution on their graphics processing unit (GPU). Several technologies with which this can be achieved are compared in terms of possible performance improvements, hardware and software support, as well as limitations of their programming model and functionality. The results of this research are applied in a practical project, consisting of performance improvements for marker detection in an Augmented Reality application for mobile devices.
The PDF is available for download and the source-code for some Android application prototypes is published on github.
February 2nd, 2014
In this paper, we propose an efficient acceleration method for the nonrigid registration of multimodal images that uses a graphics processing unit (GPU). The key contribution of our method is efficient utilization of on-chip memory for both normalized mutual information (NMI) computation and hierarchical B-spline deformation, which compose a well-known registration algorithm. We implement this registration algorithm as a compute unified device architecture (CUDA) program with an efficient parallel scheme and several optimization techniques such as hierarchical data organization, data reuse, and multiresolution representation. We experimentally evaluate our method with four clinical datasets consisting of up to 512x512x296 voxels. We find that exploitation of onchip memory achieves a 12-fold increase in speed over an off-chip memory version and, therefore, it increases the efficiency of parallel execution from 4% to 46%. We also find that our method running on a GeForce GTX 580 card is approximately 14 times faster than a fully optimized CPU-based implementation running on four cores. Some multimodal registration results are also provided to understand the limitation of our method. We believe that our highly efficient method, which completes an alignment task within a few tens of second, will be useful to realize rapid nonrigid registration.
(Kei Ikeda, Fumihiko Ino, and Kenichi Hagihara: “Efficient Acceleration of Mutual Information Computation for Nonrigid Registration Using CUDA”. Accepted for publication in the IEEE Journal of Biomedical and Health Informatics. [DOI])
October 7th, 2013
OpenCLIPP is a library providing processing primitives (image processing primitives in the first version) implemented with OpenCL for fast execution on dedicated computing devices like GPUs. Two interfaces are provided: C (similar to the Intel IPP and NVIDIA NPP libraries) and C++. OpenCLIPP is free for personal and commercial use. It can be downloaded from GitHub.
M. Akhloufi, A. Campagna, “OpenCLIPP: OpenCL Integrated Performance Primitives library for computer vision applications”, Proc. SPIE Electronic Imaging 2014, Intelligent Robots and Computer Vision XXXI: Algorithms and Techniques, P. 9025-31, February 2014.
September 22nd, 2013
This paper presents an accelerated version of copy-move image forgery detection scheme on the Graphics Processing Units or GPUs. With the replacement of analog cameras with their digital counterparts and availability of powerful image processing software packages, authentication of digital images has gained importance in the recent past. This paper focuses on improving the performance of a copy-move forgery detection scheme based on radix sort by porting it onto the GPUs. This scheme has enhanced performance and is much more efficient compared to other methods without degradation of detection results. The CPU version of the radix-sort based detection scheme was developed in Matlab and critical sections of the CPU version were coded in C-language using Matlab’s Mex interface to get the maximum performance. The GPU version was developed using Jacket GPU Engine for Matlab and performs over twelve times faster than its optimized CPU variant. The contribution this paper makes towards blind image forensics is the use of integral images for computing feature vectors of overlapping blocks in block-matching technique and acceleration of the entire copy-move forgery detection scheme on the GPUs, not found in literature.
(Jaideep Singh and Balasubramanian Raman, “A High Performance Copy-Move Image Forgery Detection Scheme on GPU”, Advances in Intelligent and Soft Computing Volume 131, 2012, pp 239-246, Proceedings of the International Conference on Soft Computing for Problem Solving (SocProS 2011). [DOI])
September 22nd, 2013
Feature detection and extraction are essential in computer vision applications such as image matching and object recognition. The Scale-Invariant Feature Transform (SIFT) algorithm is one of the most robust approaches to detect and extract distinctive invariant features from images. However, high computational complexity makes it difficult to apply the SIFT algorithm to mobile applications. Recent developments in mobile processors have enabled heterogeneous computing on mobile devices, such as smartphones and tablets. In this paper, we present an OpenCL-based implementation of the SIFT algorithm on a smartphone, taking advantage of the mobile GPU. We carefully analyze the SIFT workloads and identify the parallelism. We implemented major steps of the SIFT algorithm using both serial C++ code and OpenCL kernels targeting mobile processors, to compare the performance of different workflows. Based on the profiling results, we partition the SIFT algorithm between the CPU and GPU in a way that best exploits the parallelism and minimizes the buffer transferring time to achieve better performance. The experimental results show that we are able to achieve 8.5 FPS for keypoints detection and 19 FPS for descriptor generation without reducing the number and the quality of the keypoints. Moreover, the heterogeneous implementation can reduce energy consumption by 41% compared to an optimized CPU-only implementation.
(Guohui Wang, Blaine Rister, and Joseph R. Cavallaro: “Workload Analysis and Efficient OpenCL-based Implementation of SIFT Algorithm on a Smartphone”, 1st IEEE Global Conference on Signal and Information Processing (GlobalSIP), Dec. 2013, [PDF])
March 13th, 2013
Fastvideo have released their JPEG codec for NVIDIA GPUs. Peak performance of the codec reaches 6 GBytes per second and higher for images loadedfrom host RAM. For instance, a full-color 4K image with resolution 3840 x 2160 can be compressed by 10 times in merely 6 milliseconds on NVIDIA GeForce GTX Titan. More information: http://www.fastcompression.com
February 10th, 2013
The GPU Debayer software developed by Fastvideo can be used for demosaicing of raw 8-bit Bayer images to full-color 24-bit RGB format. The application employs the HQLI and DFPD algorithms and is tuned for NVIDIA GPUs, which results in very fast conversion, e.g., only 1.25 ms for Full HD image demosaicing on GeForce GTX 580. The software is freely available.
May 17th, 2012
This class teaches the fundamentals of parallel computing with the GPU and the CUDA programming environment. Examples are based on a series of image processing algorithms, such as those in Photoshop or Instagram. Programming and running assignments on high-end GPUs is possible, even if you don’t own one yourself. The course started Monday 4th Feb 2013 so there is still time to join. More information and enrollment: https://www.udacity.com/course/cs344.
March 18th, 2012
TunaCode has released CUVILib v1.2, a library to accelerate imaging and computer vision applications. CUVILib adds acceleration to Imaging applications from Medical, Industrial and Defense domains. It delivers very high performance and supports both CUDA and OpenCL. Modules include color operations (demosaic, conversions, correction etc), linear/non-linear filtering, feature extraction & tracking, motion estimation, image transforms and image statistics.
More information, including a free trial version: http://www.cuvilib.com/
Modern GPUs are well suited for performing image processing tasks. We utilize their high computational performance and memory bandwidth for image segmentation purposes. We segment cardiac MRI data by means of numerical solution of an anisotropic partial differential equation of the Allen-Cahn type. We implement two different algorithms for solving the equation on the CUDA architecture. One of them is based on the Runge-Kutta-Merson method for the approximation of solutions of ordinary differential equations, the other uses the GMRES method for the numerical solution of systems of linear equations. In our experiments, the CUDA implementations of both algorithms are about 3–9 times faster than corresponding 12-threaded OpenMP implementations.
(Oberhuber T., Suzuki A., Vacata J., Žabka V., “Image segmentation using CUDA implementations of the Runge-Kutta-Merson and GMRES methods“, Journal of Math-for-Industry, 2011, vol. 3, pp. 73–79 [PDF])