A virtual interface for all feature trackers, implementing the part of feature tracking that is common to any specific tracker implementation.
This class provides a quite robust tracking of features, avoiding as many outliers as possible but not all of them: more robust tracking would require application-specific information and could be done in a number of very different approaches, so this class will not try to do any kind of RANSAC or any other advanced outlier rejection; instead, it should be done by the users or the classes that employ this class.
The basic usage of this class is as follows:
CFeatureTracker_KL tracker; // Note: CFeatureTracker_KL is the most robust implementation for now. tracker.extra_params["add_new_features"] = 1; // Enable detection of new features, not only tracking tracker.extra_params[...] = ... // .... CFeatureList theFeats; // The list of features mrpt::utils::CImage previous_img, current_img; while (true) { current_img = ... // Grab new image. if ( previous_img_is_ok ) tracker.trackFeatures(previous_img, current_img, theFeats); previous_img = current_img; }
Below follows the list of optional parameters for "extra_params" which can be set and will be understood by this base class for any specific tracker implementation. Note that all parameters are double's, but boolean flags are emulated by the values 0.0 (false) and 1.0 (true).
List of parameters:
Parameter name | Default value | Comments |
add_new_features | 0 | If set to "1", the class will not only track existing features, but will also perform (after doing the actual tracking) an efficient search for new features with the FAST detector, and will add them to the passed "CFeatureList" if they fulfill a set of restrictions, as stablished by the other parameters (see add_new_feat_min_separation,add_new_feat_max_features,minimum_KLT_response_to_add). |
add_new_feat_min_separation | 15 | If add_new_features==1, this is the minimum separation (in pixels) to any other (old, or new) feature for it being considered a candidate to be added. |
add_new_feat_max_features | 100 | If add_new_features==1, FAST features are detected in each frame, and only the best add_new_feat_max_features keypoints (ordered by their KLT response) will be considered as eligible for addition to the set of tracked features. |
add_new_feat_patch_size | 11 | If add_new_features==1, for each new added feature, this is the size of the patch to be extracted around the keypoint (set to 0 if patches are not required at all). |
minimum_KLT_response_to_add | 10 | If add_new_features==1, this sets the minimum KLT response of candidate FAST features to be added in each frame, if they also fulfil the other restrictions (e.g. min.distance). |
check_KLT_response_every | 0 | If >0, it will compute the KLT response at each feature point every N frames and those below minimum_KLT_response will be marked as "lost" in their "track_status" field. |
minimum_KLT_response | 5 | See explanation of check_KLT_response_every. |
KLT_response_half_win | 4 | When computing the KLT response of features (see minimum_KLT_response and minimum_KLT_response_to_add), the window centered at the point for its estimation will be of size (2*W+1)x(2*W+1), with W being this parameter value. |
update_patches_every | 0 | If !=0, the patch associated to each feature will be updated with every N'th frame. |
This class also offers a time profiler, disabled by default (see getProfiler and enableTimeLogger).
Definition at line 135 of file tracking.h.
#include <mrpt/vision/tracking.h>
Public Member Functions | |
CGenericFeatureTracker () | |
Default ctor. | |
CGenericFeatureTracker (mrpt::utils::TParametersDouble extraParams) | |
Ctor with extra parameters. | |
virtual | ~CGenericFeatureTracker () |
Dtor. | |
void | trackFeatures (const CImage &old_img, const CImage &new_img, vision::CFeatureList &inout_featureList) |
Perform feature tracking from "old_img" to "new_img", with a (possibly empty) list of previously tracked features "inout_featureList". | |
void | trackFeaturesNewList (const CImage &old_img, const CImage &new_img, const vision::CFeatureList &in_featureList, vision::CFeatureList &out_featureList) |
A wrapper around the basic trackFeatures() method, but keeping the original list of features unmodified and returns the tracked ones in a new list. | |
const mrpt::utils::CTimeLogger & | getProfiler () const |
Returns a read-only reference to the internal time logger. | |
mrpt::utils::CTimeLogger & | getProfiler () |
Returns a reference to the internal time logger. | |
void | enableTimeLogger (bool enable=true) |
Returns a read-only reference to the internal time logger. | |
Public Attributes | |
mrpt::utils::TParametersDouble | extra_params |
Optional list of extra parameters to the algorithm. | |
Protected Member Functions | |
virtual void | trackFeatures_impl (const CImage &old_img, const CImage &new_img, vision::CFeatureList &inout_featureList)=0 |
The tracking method implementation, to be implemented in children classes. | |
Protected Attributes | |
mrpt::utils::CTimeLogger | m_timlog |
the internal time logger, disabled by default. | |
Private Attributes | |
size_t | m_update_patches_counter |
for use when "update_patches_every">=1 | |
size_t | m_check_KLT_counter |
For use when "check_KLT_response_every">=1. | |
int | m_detector_adaptive_thres |
For use in "add_new_features" == true. |
mrpt::vision::CGenericFeatureTracker::CGenericFeatureTracker | ( | ) | [inline] |
Default ctor.
Definition at line 141 of file tracking.h.
mrpt::vision::CGenericFeatureTracker::CGenericFeatureTracker | ( | mrpt::utils::TParametersDouble | extraParams | ) | [inline] |
Ctor with extra parameters.
Definition at line 144 of file tracking.h.
virtual mrpt::vision::CGenericFeatureTracker::~CGenericFeatureTracker | ( | ) | [inline, virtual] |
Dtor.
Definition at line 147 of file tracking.h.
void mrpt::vision::CGenericFeatureTracker::enableTimeLogger | ( | bool | enable = true | ) | [inline] |
Returns a read-only reference to the internal time logger.
Definition at line 184 of file tracking.h.
const mrpt::utils::CTimeLogger& mrpt::vision::CGenericFeatureTracker::getProfiler | ( | ) | const [inline] |
Returns a read-only reference to the internal time logger.
Definition at line 179 of file tracking.h.
mrpt::utils::CTimeLogger& mrpt::vision::CGenericFeatureTracker::getProfiler | ( | ) | [inline] |
Returns a reference to the internal time logger.
Definition at line 181 of file tracking.h.
void mrpt::vision::CGenericFeatureTracker::trackFeatures | ( | const CImage & | old_img, |
const CImage & | new_img, | ||
vision::CFeatureList & | inout_featureList | ||
) |
Perform feature tracking from "old_img" to "new_img", with a (possibly empty) list of previously tracked features "inout_featureList".
This is a list of parameters (in "extraParams") accepted by ALL implementations of feature tracker (see each derived class for more specific parameters).
Convert old and new images to grayscale, if they're in color.
virtual void mrpt::vision::CGenericFeatureTracker::trackFeatures_impl | ( | const CImage & | old_img, |
const CImage & | new_img, | ||
vision::CFeatureList & | inout_featureList | ||
) | [protected, pure virtual] |
The tracking method implementation, to be implemented in children classes.
Implemented in mrpt::vision::CFeatureTracker_KL, mrpt::vision::CFeatureTracker_FAST, and mrpt::vision::CFeatureTracker_PatchMatch.
void mrpt::vision::CGenericFeatureTracker::trackFeaturesNewList | ( | const CImage & | old_img, |
const CImage & | new_img, | ||
const vision::CFeatureList & | in_featureList, | ||
vision::CFeatureList & | out_featureList | ||
) | [inline] |
A wrapper around the basic trackFeatures() method, but keeping the original list of features unmodified and returns the tracked ones in a new list.
Definition at line 164 of file tracking.h.
References mrpt::vision::CFeatureList::begin(), and mrpt::vision::CFeatureList::end().
Optional list of extra parameters to the algorithm.
Definition at line 138 of file tracking.h.
size_t mrpt::vision::CGenericFeatureTracker::m_check_KLT_counter [private] |
For use when "check_KLT_response_every">=1.
Definition at line 197 of file tracking.h.
For use in "add_new_features" == true.
Reimplemented in mrpt::vision::CFeatureTracker_FAST.
Definition at line 198 of file tracking.h.
the internal time logger, disabled by default.
Definition at line 193 of file tracking.h.
size_t mrpt::vision::CGenericFeatureTracker::m_update_patches_counter [private] |
for use when "update_patches_every">=1
Definition at line 196 of file tracking.h.
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