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Pham T.Q.,Canon Information Systems Research Australia CiSRA
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Non-Maximum Suppression (NMS) is the task of finding all local maxima in an image. This is often solved using gray-scale image dilation, which requires at least 6 comparisons per pixel in 2-D. We present two solutions that use fewer than 2 comparisons per pixel with little memory overhead. The first algorithm locates 1-D peaks along the image's scan-line and compares each of these peaks against its 2-D neighborhood in a spiral scan order. The second algorithm selects local maximum candidates from the maxima of non-overlapping blocks of one-fourth the neighborhood size. Both algorithms run considerably faster than current best methods in the literature when applied to feature point detection. Matlab code of the proposed algorithms is provided for evaluation purposes. © 2010 Springer-Verlag.


Pham T.Q.,Canon Information Systems Research Australia CiSRA | Cox P.,Canon Information Systems Research Australia CiSRA
Proceedings - IEEE International Conference on Multimedia and Expo | Year: 2012

Global alignment is an important step in many imaging applications for hand-held cameras. We propose a fast algorithm that can handle large global translations in either x-or y-direction from a pan-tilt camera. The algorithm estimates the translations in x- and y-direction separately using 1D correlation of the absolute gradient projections along the x- and y-axis. Synthetic experiments show that the proposed multiple shift hypotheses approach is robust to translations up to 90% of the image width, whereas other projection-based alignment methods can handle up to 25% only. The proposed approach can also handle larger rotations than other methods. The robustness of the alignment to non-purely translational image motion and moving objects in the scene is demonstrated by a sweeping panorama application on live images from a Canon camera with minimal user interaction. © 2012 IEEE.


Pham T.Q.,Canon Information Systems Research Australia CiSRA
2013 International Conference on Digital Image Computing: Techniques and Applications, DICTA 2013 | Year: 2013

This paper presents a parallel implementation of geodesic distance transform using OpenMP. We show how a sequential-based chamfer distance algorithm can be executed on parallel processing units with shared memory such as multiple cores on a modern CPU. Experimental results show a speedup of 2.6 times on a quad-core machine can be achieved without loss in accuracy. This work forms part of a C implementation for geodesic superpixel segmentation of natural images. © 2013 IEEE.


Ambrose J.A.,University of New South Wales | Peddersen J.,University of New South Wales | Parameswaran S.,University of New South Wales | Labios A.,Canon Information Systems Research Australia CiSRA | Yachide Y.,Canon Information Systems Research Australia CiSRA
Proceedings of the Asia and South Pacific Design Automation Conference, ASP-DAC | Year: 2014

The Multiprocessor System-on-Chip (MPSoC) paradigm as a viable implementation platform for parallel processing has expanded to encompass embedded devices. The ability to execute code in parallel gives MPSoCs the potential to achieve high performance with low power consumption. In order for sequential legacy code to take advantage of the MPSoC design paradigm, it must first be partitioned into data flow graphs (such as Kahn Process Networks - KPNs) to ensure the data elements can be correctly passed between the separate processing elements that operate on them. Existing techniques are inadequate for use in complex legacy code. This paper proposes SDG2KPN, a System Dependency Graph to KPN conversion methodology targeting the conversion of legacy code. By creating KPNs at the granularity of the function-/procedure-level, SDG2KPN is the first of its kind to support shared and global variables as well as many more program patterns/application types. We also provide a design flow which allows the creation of MPSoC systems utilizing the produced KPNs. We demonstrate the applicability of our approach by retargeting several sequential applications to the Tensilica MPSoC framework. Our system parallelized AES, an application of 950 lines, in 4.8 seconds, while H.264, of 57896 lines, took 164.9 seconds to parallelize. © 2014 IEEE.


Ambrose J.A.,Canon Information Systems Research Australia CiSRA | Yachide Y.,Canon Information Systems Research Australia CiSRA | Batra K.,Canon Information Systems Research Australia CiSRA | Peddersen J.,University of New South Wales | Parameswaran S.,University of New South Wales
Proceedings of the 33rd IEEE International Conference on Computer Design, ICCD 2015 | Year: 2015

Pipeline of processors allow the execution of a sequential streaming program on multiple processors. However, partitioning sequential code for Multiprocessor Systems-on-Chips (MPSoCs), and then creating the MPSoC platform for the sequential code to execute, is a challenging problem. Parallelizing/pipelining statements within a control loop will improve the throughput of each iteration and the overall performance. Existing techniques, such as OpenMP, for parallelizing control loops is agnostic of the underlying MPSoC architecture, thus limiting the possibilities for further parallelisation. Previous techniques related to distribution of statements to MPSoCs considered homo geneous processors and not automated. In this paper, we propose a novel automated parallelization/ pipelining approach to synthesize a heterogeneous distributed pipelined MPSoC to improve the throughput of a loop (critical for streaming applications). An Integer Linear Programming (ILP)-based formulation to map statements to processor configurations is presented, in order to find the most suitable heterogeneous processor configurations for maximal throughput. Our approach complements state-of-The-Art parallelization techniques, such as OpenMP, to further improve the performance of an application. A complete MPSoC platform, for the Tensilica framework, is automatically generated within minutes using our approach for the tested applications. © 2015 IEEE.

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