本研究提出一個基於 SURF 和 RANSAC 的方法來取代傳統 OCR 方法進行書本
辨識,透過本研究根據書本特性提出的基於透視變換的N2Area 特徵點篩選法,
可將 RANSAC 的結果再進行更一步的篩選,藉此提升書本辨識的準確,同時利用
篩選所計算出的 RANSAC 殘留率當作閾值,也可以在計算重複率之前先行判定是
否要將該結果列入考量,藉此減少誤判的情況發生。但由於透視變換的對映矩
陣是基於 RANSAC 結果所計算而來,所以運算速度取決於 RANSAC 演算法的限制
而較為緩慢。而透過實驗的結果,N2Area 篩選法在進行特徵點區域落點判斷時,
應有一定的誤判,才會造成區域分割越多,反而準確率越低的情況。
從實驗結果來看,本研究方法仍有可以改良的地方;可使用 Overlapping
的方法來減少N2Area 篩選法所造成的誤判;因為計算 RANSAC 的時間為本研究
提出的方法中花費最多時間的步驟,若能改善 RANSAC 的計算時間就能夠更快的
提供比對結果,如何加快 RANSAC 的運算速度為本研究是否能實現即時檢索的關
鍵,降低 SURF 維度也是一種方法,但是 Bay 的研究[2]已經提出會因降低 SURF
維度而造成準確率降低,不過考慮到檢索可以用前 n 筆中有包含到正確圖片就
算對的情況下,或許是一個可以實作的選項之一。
42
參考文獻
[1]D.G. Lowe, "Distinctive image features from scale-invariant keypoints", In:
International journal of computer vision, 60.2(2002), 91-110.
[2]H. Bay, T.Tuytelaars, and L. Van Gool, "Surf: Speeded up robust features" , In:
Computer Vision-ECCV 2006.Springer,2006,404-417.
[3]E. Rosten andT. Drummond, "Machine learning for high-speed corner detection", In: Computer Vision-ECCV 2006.Springer,2006,430-443.
[4]E. Mair, G. D. hager, D. Burschka, M. Suppa, and G. Hirzinger, "Adaptive and generic corner detection based on the accelerated segment test", In: Computer
Vision-ECCV 2010.Springer,2010,183-196.
[5]E. Rosten, R. Porter, and T. Drummond, "Faster and better: A machine learning approach to corner detection", In: Pattern Analysis and Machine Intelligence,
IEEE Transactions on32.1(2010), 105-119.
[6]S. Leutenegger, M. Chli, and R. Y. Siegwart, "BRISK: Binary robust invariant scalable keypoints", In: Computer Vision(ICCV), 2011 IEEE International
Conference on.IEEE,2011, 2548-2555.
[7]M. Calonder, V. Lepetit, M. Ozuysal, T. Trzcinski, C. Strecha, and P. Fua, "BRIEF:
Computing a local binary descriptor very fast", In:Pattern Analysis and Machine
Intelligence, IEEE Transactions on34.7(2012), 1281-1298.
[8]E. Rublee, V. Rabaud, K. Konolige, and G. Bradski, "ORB: an efficient alternative to SIFT or SURF",In:In: Computer Vision(ICCV), 2011 IEEE International
Conference on.IEEE,2011, 2564-2571.
[9]C. Harris and M. Stephens, "A combined corner and edge detector",In: Alvey vision
conference.Vol. 15. Manchester, UK, 1988, p.50.
[10]E. Tola, V. Lepetit, and P. Fua, "Daisy: An efficient dense descriptor applied to wide-baseline stereo", In:Pattern Analysis and Machine Intelligence, IEEE
Transactions on32.5(2010), 815-830.
[11]M. A. Fischler and R. C. Bolles, "Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography", In:
43
Communications of the ACM24.6(1981),381-395.
[12]P. Heckbert. Fundamentals of Texture Mapping and Image Warping. Master’s thesis, University of California at Berkeley, Department ofElectrical Engineering and Computer Science, June 17 1989.
[13]A. Criminisi, I. Reid, and A. Zisserman, "A plane measuring device", In: Image
and Vision Computing, vol17, Issue 8, June 1999, 625–634.
[14]"Parameter values for the HDTV standards for production and international programme exchange," ed: ITU-R Rec. BT. 709-5, 2002.
[15]P.A. Viola and M.J. Jones," Rapid object detection using a boosted cascade of simple features", In: CVPR, issue 1, 2001, pp. 511–518.
[16]D. Lowe, "Object recognition from local scale-invariant features", In: Computer
Vision(ICCV), 1999 IEEE International Conference on.IEEE,1999, 1150-1157.
[17]A. Neubeck and L. Van Gool, "Efficient non-maximum suppression", In: ICPR, 2006.
[18]M. Brown and D. Lowe, "Invariant features from interest point groups", In:
BMVC, 2002.
[19]O. Miksik and K. Mikolajczyk, "Evaluation of local detectors and descriptors for fast feature matching", In: Pattern Recognition(ICPR), 2012 21st International
Conference on. IEEE, 2012, 2681-2684.
[20] T. Lindeberg, "Scale-space for discrete signals",In: Pttern Analysis and Machine
Intelligence,IEEE Transactions on 234-254, 1990.
[21]Open Library. URL:https://openlibrary.org/lists [22]Cover Browser. URL:http://www.coverbrowser.com/
[23]Amazon. URL: http://www.amazon.com
[24]Q. Fan, V. Lepetit, and P. Fua, "Daisy: An efficient dense descriptor applied to wide-baseline stereo", In:Pattern Analysis and Machine Intelligence, IEEE Transactions on 32.5(2010), 815-830.
[25]K. Mikolajczyk and C. Schmid. "A performance evaluation of local descriptors".
In: Pttern Analysis and Machine Intelligence, IEEE Transactions on 27.10(2005), 1615-1630
44
[26]L. Juan and O. Gwun. "A comparison of sift, pca-sift and surf". In: International