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...ptors provide excellent performance relative to other existing feature sets including wavelets [17,22]. The proposed descriptors are reminiscent of edge orientation histograms [4,5], SIFT descriptors =-=[12]-=- and shape contexts [1], but they are computed on a dense grid of uniformly spaced cells and they use overlapping local contrast normalizations for improved performance. We make a detailed study of th...

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...ing the border) causes a similar loss of performance, even though the resolution of the person is actually increased. 6.6 Classifier By default we use a soft (C=0.01) linear SVM trained with SVMLight =-=[10]-=- (slightly modified to reduce memory usage for problems with large dense descriptor vectors). Using a Gaussian kernel SVM increases performance by about 3% at 10 −4 FPPW at the cost of a much higher r...

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... wide baseline image matching [12], in which it provides the underlying image patch descriptor for matching scaleinvariant keypoints. SIFT-style approaches perform remarkably well in this application =-=[12,14]-=-. The Shape Context work [1] studied alternative cell and block shapes, albeit initially using only edge pixel counts without the orientation histogramming that makes the representation so effective. ...

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...e postponed until §6. The method is based on evaluating well-normalized local histograms of image gradient orientations in a dense grid. Similar features have seen increasing use over the past decade =-=[4,5,12,15]-=-. The basic idea is that local object appearance and shape can often be characterized rather well by the distribution of local intensity gradients orsInput image Normalize gamma & colour Compute gradi...

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...he main conclusions are summarized in §7. 2 Previous Work There is an extensive literature on object detection, but here we mention just a few relevant papers on human detection [18,17,22,16,20]. See =-=[6]-=- for a survey. Papageorgiou et al [18] describe a pedestrian detector based on a polynomial SVM using rectified Haar wavelets as input descriptors, with a parts (subwindow) based variant in [17]. Depo...

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... box filters at 45 ◦ intervals and the corresponding 2 nd derivative xy filter. PCA-SIFT. These descriptors are based on projecting gradient images onto a basis learned from training images using PCA =-=[11]-=-. Ke & Sukthankar found that they outperformed SIFT for key point based matching, but this is controversial [14]. Our implementation uses 16×16 blocks with the same derivative scale, overlap, etc., se...

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...ure sets for human detection, showing that locally normalized Histogram of Oriented Gradient (HOG) descriptors provide excellent performance relative to other existing feature sets including wavelets =-=[17,22]-=-. The proposed descriptors are reminiscent of edge orientation histograms [4,5], SIFT descriptors [12] and shape contexts [1], but they are computed on a dense grid of uniformly spaced cells and they ...

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...ure sets for human detection, showing that locally normalized Histogram of Oriented Gradient (HOG) descriptors provide excellent performance relative to other existing feature sets including wavelets =-=[17,22]-=-. The proposed descriptors are reminiscent of edge orientation histograms [4,5], SIFT descriptors [12] and shape contexts [1], but they are computed on a dense grid of uniformly spaced cells and they ...

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...the process in §5–6. The main conclusions are summarized in §7. 2 Previous Work There is an extensive literature on object detection, but here we mention just a few relevant papers on human detection =-=[18,17,22,16,20]-=-. See [6] for a survey. Papageorgiou et al [18] describe a pedestrian detector based on a polynomial SVM using rectified Haar wavelets as input descriptors, with a parts (subwindow) based variant in [...

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...ased on a polynomial SVM using rectified Haar wavelets as input descriptors, with a parts (subwindow) based variant in [17]. Depoortere et al give an optimized version of this [2]. Gavrila & Philomen =-=[8]-=- take a more direct approach, extracting edge images and matching them to a set of learned exemplars using chamfer distance. This has been used in a practical real-time pedestrian detection system [7]...

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...d an articulated body detector by incorporating SVM based limb classifiers over 1 st and 2 nd order Gaussian filters in a dynamic programming framework similar to those of Felzenszwalb & Huttenlocher =-=[3]-=- and Ioffe & Forsyth [9]. Mikolajczyk et al [16] use combinations of orientationposition histograms with binary-thresholded gradient magnitudes to build a parts based method containing detectors for f...

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...ed Gradient (HOG) descriptors provide excellent performance relative to other existing feature sets including wavelets [17,22]. The proposed descriptors are reminiscent of edge orientation histograms =-=[4,5]-=-, SIFT descriptors [12] and shape contexts [1], but they are computed on a dense grid of uniformly spaced cells and they use overlapping local contrast normalizations for improved performance. We make...

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...would allow fine coding of nearby structure to be combined with coarser coding of wider context, and the fact that the transformation from the visual field to the V1 cortex in primates is logarithmic =-=[21]-=-. However small descriptors with very few radial bins turn out to give the best performance, so in practice there is little inhomogeneity or context. It is probably better to think of C-HOG’s simply a...

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...the process in §5–6. The main conclusions are summarized in §7. 2 Previous Work There is an extensive literature on object detection, but here we mention just a few relevant papers on human detection =-=[18,17,22,16,20]-=-. See [6] for a survey. Papageorgiou et al [18] describe a pedestrian detector based on a polynomial SVM using rectified Haar wavelets as input descriptors, with a parts (subwindow) based variant in [...

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...tector by incorporating SVM based limb classifiers over 1 st and 2 nd order Gaussian filters in a dynamic programming framework similar to those of Felzenszwalb & Huttenlocher [3] and Ioffe & Forsyth =-=[9]-=-. Mikolajczyk et al [16] use combinations of orientationposition histograms with binary-thresholded gradient magnitudes to build a parts based method containing detectors for faces, heads, and front a...

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...ed Gradient (HOG) descriptors provide excellent performance relative to other existing feature sets including wavelets [17,22]. The proposed descriptors are reminiscent of edge orientation histograms =-=[4,5]-=-, SIFT descriptors [12] and shape contexts [1], but they are computed on a dense grid of uniformly spaced cells and they use overlapping local contrast normalizations for improved performance. We make...

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...[8] take a more direct approach, extracting edge images and matching them to a set of learned exemplars using chamfer distance. This has been used in a practical real-time pedestrian detection system =-=[7]-=-. Viola et al [22] build an efficient moving person detector, using AdaBoost to train a chain of progressively more complex region rejection rules based on Haar-like wavelets and space-time difference...

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...e postponed until x6. The method is based on evaluating well-normalized local histograms of image gradient orientations in a dense grid. Similar features have seen increasing use over the past decade =-=[4,5,12,15]-=-. The basic idea is that local object appearance and shape can often be characterized rather well by the distribution of local intensity gradients or 1 colour Normalize gamma & gradients Compute into ...

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... a pedestrian detector based on a polynomial SVM using rectified Haar wavelets as input descriptors, with a parts (subwindow) based variant in [17]. Depoortere et al give an optimized version of this =-=[2]-=-. Gavrila & Philomen [8] take a more direct approach, extracting edge images and matching them to a set of learned exemplars using chamfer distance. This has been used in a practical real-time pedestr...

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...performance relative to other existing feature sets including wavelets [17,22]. The proposed descriptors are reminiscent of edge orientation histograms [4,5], SIFT descriptors [12] and shape contexts =-=[1]-=-, but they are computed on a dense grid of uniformly spaced cells and they use overlapping local contrast normalizations for improved performance. We make a detailed study of the effects of various im...

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...] build an efficient moving person detector, using AdaBoost to train a chain of progressively more complex region rejection rules based on Haar-like wavelets and space-time differences. Ronfard et al =-=[19]-=- build an articulated body detector by incorporating SVM based limb classifiers over 1 st and 2 nd order Gaussian filters in a dynamic programming framework similar to those of Felzenszwalb & Huttenlo...

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...y detector by incorporating SVM based limb classiers over 1st and 2nd order Gaussian lters in a dynamic programming framework similar to those of Felzenszwalb & Huttenlocher [3] and Ioffe & Forsyth =-=[9]-=-. Mikolajczyk et al [16] use combinations of orientationposition histograms with binary-thresholded gradient magnitudes to build a parts based method containing detectors for faces, heads, and front a...