Redukowanie czasu obliczeń transformaty Hougha z wykorzystaniem preselekcji implementowane na GPGPU

• Autorzy: Mazurek P.

Warianty tytułu

EN

Reducing the computation time of the Hough Transform implemented on GPGPU using preselection of circles

• Języki publikacji: PL

Abstrakty

PL

W artykule przedstawiono algorytm rzadkiego próbkowania okręgu dla transformaty Hougha, w celu preselekcji okręgów do dalszego przetwarzania. Rozwiązanie pozwala na skrócenie czasu obliczeń, rzędu dwóch razy dla implementacji z wykorzystaniem programowanej karty graficznej (GPGPU). Może ono być zastosowywane do wykrycia jednokolorowej kryzy wokół lustra sferycznego lub półsferycznego służącego do pomiaru oświetlenia. Dzięki temu można analizować obraz wideo zawierający pomiary z różnych obszarów.

EN

The Hough Transform (HT) is a very powerful algorithm for the detection of shapes. It is used for the detection of the flange of a light probe (Fig. 1). GPGPU processing is necessary for HT computation. The proposed algorithm (Fig. 4) is based on the preselection of circles for further computation (Fig. 3). Selection of the circles based on a limited set of pixel samples allows reduction of the processing time up to two times. The reduction is dependent on the image content, but the test shows that the influence of the number of the tested radiuses is less. About one second of the processing time is necessary, so larger images need tens of seconds for computation (Fig. 5). This algorithm uses exhaustive search over all positions and radiuses. One of the interesting applications of the HT is the estimation of the position and diameter of a circle related to the flange of a light probe [2, 3]. Light probes are used for computer graphics applications and they allow application of the real world measurements of light using the Image Based Lighting (IBL) technique. The GPGPU implementation use CUDA based code (CUDA v4.0) [10,11] and 16x8 organization of threads is assumed. The technique proposed for the time and spatial synchronization of the multiple threads for more synchronous read operation from a global memory is applied [7]. The global memory is large and slow, so a GPGPU-global memory interface is the main bottleneck of the system. Synchronization of accesses allows coalescence read operations.

Słowa kluczowe

PL

transformata Hougha; próbnik światła; pomiary oświetlenia; GPGPU

EN

Hough transform; light probe; light measurements; GPGPU

• Wydawca: Wydawnictwo PAK
• Czasopismo: Pomiary Automatyka Kontrola
• Rocznik: 2013
• Tom: R. 59, nr 11
• Strony: 1171--1173
• Opis fizyczny: Bibliogr. 14 poz., rys., schem., wzory

Twórcy

autor

Mazurek P.

• Zachodniopomorski Uniwersytet Technologiczny w Szczecinie,Katedra Przetwarzania Sygnałów i Inżynierii Multimedialnej, 26 kwietnia 10, 71-126 Szczecin

Bibliografia

• [1] Hough P. V. C., Arbor A.: Method and Means for Recognizing Com-plex Patterns, US Patent no. 3,069,654, 1962.
• [2] Debevec P.: Rendering Synthetic Objects into Real Scenes: Bridging Traditional and Image-based Graphics with Global Illumination and High Dynamic Range Photography, SIGGRAPH 98, 189-198, 1998.
• [3] Debevec P.: Light Probe Image Gallery, http://www.pauldebevec. com/ Probes/
• [4] Frejlichowski D.: An Experimental Comparison of Seven Shape Descriptors in the General Shape Analysis Problem. ICIAR 2010, Part I, Lecture Notes in Computer Science, vol. 6111, 294–305, 2010.
• [5] Frejlichowski D.: Analysis of Four Polar Shape Descriptors Properties in an Exemplary Application, ICCVG 2010, Part I, LNCS vol.6374, 376–383, 2010.
• [6] Mazurek P.: Estimation of position of the light probe device for photorealistic computer animation purposes, Elektronika – konstrukcje, technologie, zastosowania, 42-44, R. LII no.1, 2011.
• [7] Mazurek P.: Circle parameters estimation using Hough transform implemented on GPGPU, Measurement Automation and Monitoring, vol. 57, no. 8, 886-898, 2011.
• [8] Mazurek P.: Optymalizacja transformaty Hougha dla okręgu z wykorzystaniem techniki odrzucenia implementowana na GPGPU, Measurement Automation and Monitoring, vol. 58, no. 7, 587-589, 2012.
• [9] Mazurek P.: Light estimation using light probe devices, Electrical Review, R. 89 no. 3b/2013, 312-314, 2013.
• [10] NVIDIA CUDA C Programming Guide v.4.0, NVidia, 2011.
• [11] NVIDIA CUDA, CUDA C Best Practices Guide v.4.0, NVidia, 2011.
• [12] Reinhard E., Ward G., Pattanaik S., Debevec P.: High Dynamic Range Imaging. Acquisition, Display, and Image–Based Lighting, Morgan Kaufmann, 2005.
• [13] Unger J., Gustavson S., Ollila M., Johannesson M., A Real Time Light Probe, In Proceedings of the 25th Eurographics Annual Conference, Short Papers and Interactive Demos, 17–21, 2004.
• [14] Unger J., Gustavson S., Kronander J., Larsson P., Bonnet G., Kaiser G., Next Generation Image Based Lighting, SIGGRAPH 2011, Talk, Vancouver, Canada, August 7–11, 2011, http://webstaff.itn.liu.se/ ˜jonun/web/papers/2011-Siggraph/SiggraphTalk2011.pdf