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ultralytics.trackers.utils.gmc.GMC

Classe Generalized Motion Compensation (GMC) per il tracciamento e il rilevamento degli oggetti nei fotogrammi video.

Questa classe fornisce metodi per il tracciamento e il rilevamento di oggetti basati su diversi algoritmi di tracciamento, tra cui ORB, SIFT, ECC e Sparse Optical Flow. Supporta anche il downscaling dei fotogrammi per ottenere una maggiore efficienza computazionale.

Attributi:

Nome Tipo Descrizione
method str

Il metodo utilizzato per il tracciamento. Le opzioni includono "orb", "sift", "ecc", "sparseOptFlow", "none".

downscale int

Fattore con cui ridimensionare i fotogrammi per l'elaborazione.

prevFrame ndarray

Memorizza il fotogramma precedente per il tracciamento.

prevKeyPoints list

Memorizza i punti chiave del fotogramma precedente.

prevDescriptors ndarray

Memorizza i descrittori del fotogramma precedente.

initializedFirstFrame bool

Flag per indicare se il primo fotogramma è stato elaborato.

Metodi:

Nome Descrizione
__init__

Inizializza un oggetto GMC con il metodo specificato e il fattore di ridimensionamento.

apply

Applica il metodo scelto a un fotogramma grezzo e, facoltativamente, utilizza i rilevamenti i rilevamenti forniti.

applyEcc

Applica l'algoritmo ECC a un fotogramma grezzo.

applyFeatures

Applica metodi basati su caratteristiche come ORB o SIFT a un fotogramma grezzo.

applySparseOptFlow

Applica il metodo Sparse Optical Flow a un fotogramma grezzo.

Codice sorgente in ultralytics/trackers/utils/gmc.py
class GMC:
    """
    Generalized Motion Compensation (GMC) class for tracking and object detection in video frames.

    This class provides methods for tracking and detecting objects based on several tracking algorithms including ORB,
    SIFT, ECC, and Sparse Optical Flow. It also supports downscaling of frames for computational efficiency.

    Attributes:
        method (str): The method used for tracking. Options include 'orb', 'sift', 'ecc', 'sparseOptFlow', 'none'.
        downscale (int): Factor by which to downscale the frames for processing.
        prevFrame (np.ndarray): Stores the previous frame for tracking.
        prevKeyPoints (list): Stores the keypoints from the previous frame.
        prevDescriptors (np.ndarray): Stores the descriptors from the previous frame.
        initializedFirstFrame (bool): Flag to indicate if the first frame has been processed.

    Methods:
        __init__(self, method='sparseOptFlow', downscale=2): Initializes a GMC object with the specified method
                                                              and downscale factor.
        apply(self, raw_frame, detections=None): Applies the chosen method to a raw frame and optionally uses
                                                 provided detections.
        applyEcc(self, raw_frame, detections=None): Applies the ECC algorithm to a raw frame.
        applyFeatures(self, raw_frame, detections=None): Applies feature-based methods like ORB or SIFT to a raw frame.
        applySparseOptFlow(self, raw_frame, detections=None): Applies the Sparse Optical Flow method to a raw frame.
    """

    def __init__(self, method: str = "sparseOptFlow", downscale: int = 2) -> None:
        """
        Initialize a video tracker with specified parameters.

        Args:
            method (str): The method used for tracking. Options include 'orb', 'sift', 'ecc', 'sparseOptFlow', 'none'.
            downscale (int): Downscale factor for processing frames.
        """
        super().__init__()

        self.method = method
        self.downscale = max(1, downscale)

        if self.method == "orb":
            self.detector = cv2.FastFeatureDetector_create(20)
            self.extractor = cv2.ORB_create()
            self.matcher = cv2.BFMatcher(cv2.NORM_HAMMING)

        elif self.method == "sift":
            self.detector = cv2.SIFT_create(nOctaveLayers=3, contrastThreshold=0.02, edgeThreshold=20)
            self.extractor = cv2.SIFT_create(nOctaveLayers=3, contrastThreshold=0.02, edgeThreshold=20)
            self.matcher = cv2.BFMatcher(cv2.NORM_L2)

        elif self.method == "ecc":
            number_of_iterations = 5000
            termination_eps = 1e-6
            self.warp_mode = cv2.MOTION_EUCLIDEAN
            self.criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, number_of_iterations, termination_eps)

        elif self.method == "sparseOptFlow":
            self.feature_params = dict(
                maxCorners=1000, qualityLevel=0.01, minDistance=1, blockSize=3, useHarrisDetector=False, k=0.04
            )

        elif self.method in {"none", "None", None}:
            self.method = None
        else:
            raise ValueError(f"Error: Unknown GMC method:{method}")

        self.prevFrame = None
        self.prevKeyPoints = None
        self.prevDescriptors = None
        self.initializedFirstFrame = False

    def apply(self, raw_frame: np.array, detections: list = None) -> np.array:
        """
        Apply object detection on a raw frame using specified method.

        Args:
            raw_frame (np.ndarray): The raw frame to be processed.
            detections (list): List of detections to be used in the processing.

        Returns:
            (np.ndarray): Processed frame.

        Examples:
            >>> gmc = GMC()
            >>> gmc.apply(np.array([[1, 2, 3], [4, 5, 6]]))
            array([[1, 2, 3],
                   [4, 5, 6]])
        """
        if self.method in {"orb", "sift"}:
            return self.applyFeatures(raw_frame, detections)
        elif self.method == "ecc":
            return self.applyEcc(raw_frame)
        elif self.method == "sparseOptFlow":
            return self.applySparseOptFlow(raw_frame)
        else:
            return np.eye(2, 3)

    def applyEcc(self, raw_frame: np.array) -> np.array:
        """
        Apply ECC algorithm to a raw frame.

        Args:
            raw_frame (np.ndarray): The raw frame to be processed.

        Returns:
            (np.ndarray): Processed frame.

        Examples:
            >>> gmc = GMC()
            >>> gmc.applyEcc(np.array([[1, 2, 3], [4, 5, 6]]))
            array([[1, 2, 3],
                   [4, 5, 6]])
        """
        height, width, _ = raw_frame.shape
        frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
        H = np.eye(2, 3, dtype=np.float32)

        # Downscale image
        if self.downscale > 1.0:
            frame = cv2.GaussianBlur(frame, (3, 3), 1.5)
            frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))
            width = width // self.downscale
            height = height // self.downscale

        # Handle first frame
        if not self.initializedFirstFrame:
            # Initialize data
            self.prevFrame = frame.copy()

            # Initialization done
            self.initializedFirstFrame = True

            return H

        # Run the ECC algorithm. The results are stored in warp_matrix.
        # (cc, H) = cv2.findTransformECC(self.prevFrame, frame, H, self.warp_mode, self.criteria)
        try:
            (_, H) = cv2.findTransformECC(self.prevFrame, frame, H, self.warp_mode, self.criteria, None, 1)
        except Exception as e:
            LOGGER.warning(f"WARNING: find transform failed. Set warp as identity {e}")

        return H

    def applyFeatures(self, raw_frame: np.array, detections: list = None) -> np.array:
        """
        Apply feature-based methods like ORB or SIFT to a raw frame.

        Args:
            raw_frame (np.ndarray): The raw frame to be processed.
            detections (list): List of detections to be used in the processing.

        Returns:
            (np.ndarray): Processed frame.

        Examples:
            >>> gmc = GMC()
            >>> gmc.applyFeatures(np.array([[1, 2, 3], [4, 5, 6]]))
            array([[1, 2, 3],
                   [4, 5, 6]])
        """
        height, width, _ = raw_frame.shape
        frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
        H = np.eye(2, 3)

        # Downscale image
        if self.downscale > 1.0:
            frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))
            width = width // self.downscale
            height = height // self.downscale

        # Find the keypoints
        mask = np.zeros_like(frame)
        mask[int(0.02 * height) : int(0.98 * height), int(0.02 * width) : int(0.98 * width)] = 255
        if detections is not None:
            for det in detections:
                tlbr = (det[:4] / self.downscale).astype(np.int_)
                mask[tlbr[1] : tlbr[3], tlbr[0] : tlbr[2]] = 0

        keypoints = self.detector.detect(frame, mask)

        # Compute the descriptors
        keypoints, descriptors = self.extractor.compute(frame, keypoints)

        # Handle first frame
        if not self.initializedFirstFrame:
            # Initialize data
            self.prevFrame = frame.copy()
            self.prevKeyPoints = copy.copy(keypoints)
            self.prevDescriptors = copy.copy(descriptors)

            # Initialization done
            self.initializedFirstFrame = True

            return H

        # Match descriptors
        knnMatches = self.matcher.knnMatch(self.prevDescriptors, descriptors, 2)

        # Filter matches based on smallest spatial distance
        matches = []
        spatialDistances = []

        maxSpatialDistance = 0.25 * np.array([width, height])

        # Handle empty matches case
        if len(knnMatches) == 0:
            # Store to next iteration
            self.prevFrame = frame.copy()
            self.prevKeyPoints = copy.copy(keypoints)
            self.prevDescriptors = copy.copy(descriptors)

            return H

        for m, n in knnMatches:
            if m.distance < 0.9 * n.distance:
                prevKeyPointLocation = self.prevKeyPoints[m.queryIdx].pt
                currKeyPointLocation = keypoints[m.trainIdx].pt

                spatialDistance = (
                    prevKeyPointLocation[0] - currKeyPointLocation[0],
                    prevKeyPointLocation[1] - currKeyPointLocation[1],
                )

                if (np.abs(spatialDistance[0]) < maxSpatialDistance[0]) and (
                    np.abs(spatialDistance[1]) < maxSpatialDistance[1]
                ):
                    spatialDistances.append(spatialDistance)
                    matches.append(m)

        meanSpatialDistances = np.mean(spatialDistances, 0)
        stdSpatialDistances = np.std(spatialDistances, 0)

        inliers = (spatialDistances - meanSpatialDistances) < 2.5 * stdSpatialDistances

        goodMatches = []
        prevPoints = []
        currPoints = []
        for i in range(len(matches)):
            if inliers[i, 0] and inliers[i, 1]:
                goodMatches.append(matches[i])
                prevPoints.append(self.prevKeyPoints[matches[i].queryIdx].pt)
                currPoints.append(keypoints[matches[i].trainIdx].pt)

        prevPoints = np.array(prevPoints)
        currPoints = np.array(currPoints)

        # Draw the keypoint matches on the output image
        # if False:
        #     import matplotlib.pyplot as plt
        #     matches_img = np.hstack((self.prevFrame, frame))
        #     matches_img = cv2.cvtColor(matches_img, cv2.COLOR_GRAY2BGR)
        #     W = self.prevFrame.shape[1]
        #     for m in goodMatches:
        #         prev_pt = np.array(self.prevKeyPoints[m.queryIdx].pt, dtype=np.int_)
        #         curr_pt = np.array(keypoints[m.trainIdx].pt, dtype=np.int_)
        #         curr_pt[0] += W
        #         color = np.random.randint(0, 255, 3)
        #         color = (int(color[0]), int(color[1]), int(color[2]))
        #
        #         matches_img = cv2.line(matches_img, prev_pt, curr_pt, tuple(color), 1, cv2.LINE_AA)
        #         matches_img = cv2.circle(matches_img, prev_pt, 2, tuple(color), -1)
        #         matches_img = cv2.circle(matches_img, curr_pt, 2, tuple(color), -1)
        #
        #     plt.figure()
        #     plt.imshow(matches_img)
        #     plt.show()

        # Find rigid matrix
        if prevPoints.shape[0] > 4:
            H, inliers = cv2.estimateAffinePartial2D(prevPoints, currPoints, cv2.RANSAC)

            # Handle downscale
            if self.downscale > 1.0:
                H[0, 2] *= self.downscale
                H[1, 2] *= self.downscale
        else:
            LOGGER.warning("WARNING: not enough matching points")

        # Store to next iteration
        self.prevFrame = frame.copy()
        self.prevKeyPoints = copy.copy(keypoints)
        self.prevDescriptors = copy.copy(descriptors)

        return H

    def applySparseOptFlow(self, raw_frame: np.array) -> np.array:
        """
        Apply Sparse Optical Flow method to a raw frame.

        Args:
            raw_frame (np.ndarray): The raw frame to be processed.

        Returns:
            (np.ndarray): Processed frame.

        Examples:
            >>> gmc = GMC()
            >>> gmc.applySparseOptFlow(np.array([[1, 2, 3], [4, 5, 6]]))
            array([[1, 2, 3],
                   [4, 5, 6]])
        """
        height, width, _ = raw_frame.shape
        frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
        H = np.eye(2, 3)

        # Downscale image
        if self.downscale > 1.0:
            frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))

        # Find the keypoints
        keypoints = cv2.goodFeaturesToTrack(frame, mask=None, **self.feature_params)

        # Handle first frame
        if not self.initializedFirstFrame or self.prevKeyPoints is None:
            self.prevFrame = frame.copy()
            self.prevKeyPoints = copy.copy(keypoints)
            self.initializedFirstFrame = True
            return H

        # Find correspondences
        matchedKeypoints, status, _ = cv2.calcOpticalFlowPyrLK(self.prevFrame, frame, self.prevKeyPoints, None)

        # Leave good correspondences only
        prevPoints = []
        currPoints = []

        for i in range(len(status)):
            if status[i]:
                prevPoints.append(self.prevKeyPoints[i])
                currPoints.append(matchedKeypoints[i])

        prevPoints = np.array(prevPoints)
        currPoints = np.array(currPoints)

        # Find rigid matrix
        if (prevPoints.shape[0] > 4) and (prevPoints.shape[0] == prevPoints.shape[0]):
            H, _ = cv2.estimateAffinePartial2D(prevPoints, currPoints, cv2.RANSAC)

            if self.downscale > 1.0:
                H[0, 2] *= self.downscale
                H[1, 2] *= self.downscale
        else:
            LOGGER.warning("WARNING: not enough matching points")

        self.prevFrame = frame.copy()
        self.prevKeyPoints = copy.copy(keypoints)

        return H

    def reset_params(self) -> None:
        """Reset parameters."""
        self.prevFrame = None
        self.prevKeyPoints = None
        self.prevDescriptors = None
        self.initializedFirstFrame = False

__init__(method='sparseOptFlow', downscale=2)

Inizializza un tracker video con i parametri specificati.

Parametri:

Nome Tipo Descrizione Predefinito
method str

Il metodo utilizzato per il tracciamento. Le opzioni includono "orb", "sift", "ecc", "sparseOptFlow", "none".

'sparseOptFlow'
downscale int

Fattore di ridimensionamento per l'elaborazione dei fotogrammi.

2
Codice sorgente in ultralytics/trackers/utils/gmc.py
def __init__(self, method: str = "sparseOptFlow", downscale: int = 2) -> None:
    """
    Initialize a video tracker with specified parameters.

    Args:
        method (str): The method used for tracking. Options include 'orb', 'sift', 'ecc', 'sparseOptFlow', 'none'.
        downscale (int): Downscale factor for processing frames.
    """
    super().__init__()

    self.method = method
    self.downscale = max(1, downscale)

    if self.method == "orb":
        self.detector = cv2.FastFeatureDetector_create(20)
        self.extractor = cv2.ORB_create()
        self.matcher = cv2.BFMatcher(cv2.NORM_HAMMING)

    elif self.method == "sift":
        self.detector = cv2.SIFT_create(nOctaveLayers=3, contrastThreshold=0.02, edgeThreshold=20)
        self.extractor = cv2.SIFT_create(nOctaveLayers=3, contrastThreshold=0.02, edgeThreshold=20)
        self.matcher = cv2.BFMatcher(cv2.NORM_L2)

    elif self.method == "ecc":
        number_of_iterations = 5000
        termination_eps = 1e-6
        self.warp_mode = cv2.MOTION_EUCLIDEAN
        self.criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, number_of_iterations, termination_eps)

    elif self.method == "sparseOptFlow":
        self.feature_params = dict(
            maxCorners=1000, qualityLevel=0.01, minDistance=1, blockSize=3, useHarrisDetector=False, k=0.04
        )

    elif self.method in {"none", "None", None}:
        self.method = None
    else:
        raise ValueError(f"Error: Unknown GMC method:{method}")

    self.prevFrame = None
    self.prevKeyPoints = None
    self.prevDescriptors = None
    self.initializedFirstFrame = False

apply(raw_frame, detections=None)

Applica il rilevamento degli oggetti su un fotogramma grezzo utilizzando il metodo specificato.

Parametri:

Nome Tipo Descrizione Predefinito
raw_frame ndarray

Il fotogramma grezzo da elaborare.

richiesto
detections list

Elenco dei rilevamenti da utilizzare nell'elaborazione.

None

Restituzione:

Tipo Descrizione
ndarray

Cornice elaborata.

Esempi:

>>> gmc = GMC()
>>> gmc.apply(np.array([[1, 2, 3], [4, 5, 6]]))
array([[1, 2, 3],
       [4, 5, 6]])
Codice sorgente in ultralytics/trackers/utils/gmc.py
def apply(self, raw_frame: np.array, detections: list = None) -> np.array:
    """
    Apply object detection on a raw frame using specified method.

    Args:
        raw_frame (np.ndarray): The raw frame to be processed.
        detections (list): List of detections to be used in the processing.

    Returns:
        (np.ndarray): Processed frame.

    Examples:
        >>> gmc = GMC()
        >>> gmc.apply(np.array([[1, 2, 3], [4, 5, 6]]))
        array([[1, 2, 3],
               [4, 5, 6]])
    """
    if self.method in {"orb", "sift"}:
        return self.applyFeatures(raw_frame, detections)
    elif self.method == "ecc":
        return self.applyEcc(raw_frame)
    elif self.method == "sparseOptFlow":
        return self.applySparseOptFlow(raw_frame)
    else:
        return np.eye(2, 3)

applyEcc(raw_frame)

Applica l'algoritmo ECC a un fotogramma grezzo.

Parametri:

Nome Tipo Descrizione Predefinito
raw_frame ndarray

Il fotogramma grezzo da elaborare.

richiesto

Restituzione:

Tipo Descrizione
ndarray

Cornice elaborata.

Esempi:

>>> gmc = GMC()
>>> gmc.applyEcc(np.array([[1, 2, 3], [4, 5, 6]]))
array([[1, 2, 3],
       [4, 5, 6]])
Codice sorgente in ultralytics/trackers/utils/gmc.py
def applyEcc(self, raw_frame: np.array) -> np.array:
    """
    Apply ECC algorithm to a raw frame.

    Args:
        raw_frame (np.ndarray): The raw frame to be processed.

    Returns:
        (np.ndarray): Processed frame.

    Examples:
        >>> gmc = GMC()
        >>> gmc.applyEcc(np.array([[1, 2, 3], [4, 5, 6]]))
        array([[1, 2, 3],
               [4, 5, 6]])
    """
    height, width, _ = raw_frame.shape
    frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
    H = np.eye(2, 3, dtype=np.float32)

    # Downscale image
    if self.downscale > 1.0:
        frame = cv2.GaussianBlur(frame, (3, 3), 1.5)
        frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))
        width = width // self.downscale
        height = height // self.downscale

    # Handle first frame
    if not self.initializedFirstFrame:
        # Initialize data
        self.prevFrame = frame.copy()

        # Initialization done
        self.initializedFirstFrame = True

        return H

    # Run the ECC algorithm. The results are stored in warp_matrix.
    # (cc, H) = cv2.findTransformECC(self.prevFrame, frame, H, self.warp_mode, self.criteria)
    try:
        (_, H) = cv2.findTransformECC(self.prevFrame, frame, H, self.warp_mode, self.criteria, None, 1)
    except Exception as e:
        LOGGER.warning(f"WARNING: find transform failed. Set warp as identity {e}")

    return H

applyFeatures(raw_frame, detections=None)

Applicare metodi basati su caratteristiche come ORB o SIFT a un fotogramma grezzo.

Parametri:

Nome Tipo Descrizione Predefinito
raw_frame ndarray

Il fotogramma grezzo da elaborare.

richiesto
detections list

Elenco dei rilevamenti da utilizzare nell'elaborazione.

None

Restituzione:

Tipo Descrizione
ndarray

Cornice elaborata.

Esempi:

>>> gmc = GMC()
>>> gmc.applyFeatures(np.array([[1, 2, 3], [4, 5, 6]]))
array([[1, 2, 3],
       [4, 5, 6]])
Codice sorgente in ultralytics/trackers/utils/gmc.py
def applyFeatures(self, raw_frame: np.array, detections: list = None) -> np.array:
    """
    Apply feature-based methods like ORB or SIFT to a raw frame.

    Args:
        raw_frame (np.ndarray): The raw frame to be processed.
        detections (list): List of detections to be used in the processing.

    Returns:
        (np.ndarray): Processed frame.

    Examples:
        >>> gmc = GMC()
        >>> gmc.applyFeatures(np.array([[1, 2, 3], [4, 5, 6]]))
        array([[1, 2, 3],
               [4, 5, 6]])
    """
    height, width, _ = raw_frame.shape
    frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
    H = np.eye(2, 3)

    # Downscale image
    if self.downscale > 1.0:
        frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))
        width = width // self.downscale
        height = height // self.downscale

    # Find the keypoints
    mask = np.zeros_like(frame)
    mask[int(0.02 * height) : int(0.98 * height), int(0.02 * width) : int(0.98 * width)] = 255
    if detections is not None:
        for det in detections:
            tlbr = (det[:4] / self.downscale).astype(np.int_)
            mask[tlbr[1] : tlbr[3], tlbr[0] : tlbr[2]] = 0

    keypoints = self.detector.detect(frame, mask)

    # Compute the descriptors
    keypoints, descriptors = self.extractor.compute(frame, keypoints)

    # Handle first frame
    if not self.initializedFirstFrame:
        # Initialize data
        self.prevFrame = frame.copy()
        self.prevKeyPoints = copy.copy(keypoints)
        self.prevDescriptors = copy.copy(descriptors)

        # Initialization done
        self.initializedFirstFrame = True

        return H

    # Match descriptors
    knnMatches = self.matcher.knnMatch(self.prevDescriptors, descriptors, 2)

    # Filter matches based on smallest spatial distance
    matches = []
    spatialDistances = []

    maxSpatialDistance = 0.25 * np.array([width, height])

    # Handle empty matches case
    if len(knnMatches) == 0:
        # Store to next iteration
        self.prevFrame = frame.copy()
        self.prevKeyPoints = copy.copy(keypoints)
        self.prevDescriptors = copy.copy(descriptors)

        return H

    for m, n in knnMatches:
        if m.distance < 0.9 * n.distance:
            prevKeyPointLocation = self.prevKeyPoints[m.queryIdx].pt
            currKeyPointLocation = keypoints[m.trainIdx].pt

            spatialDistance = (
                prevKeyPointLocation[0] - currKeyPointLocation[0],
                prevKeyPointLocation[1] - currKeyPointLocation[1],
            )

            if (np.abs(spatialDistance[0]) < maxSpatialDistance[0]) and (
                np.abs(spatialDistance[1]) < maxSpatialDistance[1]
            ):
                spatialDistances.append(spatialDistance)
                matches.append(m)

    meanSpatialDistances = np.mean(spatialDistances, 0)
    stdSpatialDistances = np.std(spatialDistances, 0)

    inliers = (spatialDistances - meanSpatialDistances) < 2.5 * stdSpatialDistances

    goodMatches = []
    prevPoints = []
    currPoints = []
    for i in range(len(matches)):
        if inliers[i, 0] and inliers[i, 1]:
            goodMatches.append(matches[i])
            prevPoints.append(self.prevKeyPoints[matches[i].queryIdx].pt)
            currPoints.append(keypoints[matches[i].trainIdx].pt)

    prevPoints = np.array(prevPoints)
    currPoints = np.array(currPoints)

    # Draw the keypoint matches on the output image
    # if False:
    #     import matplotlib.pyplot as plt
    #     matches_img = np.hstack((self.prevFrame, frame))
    #     matches_img = cv2.cvtColor(matches_img, cv2.COLOR_GRAY2BGR)
    #     W = self.prevFrame.shape[1]
    #     for m in goodMatches:
    #         prev_pt = np.array(self.prevKeyPoints[m.queryIdx].pt, dtype=np.int_)
    #         curr_pt = np.array(keypoints[m.trainIdx].pt, dtype=np.int_)
    #         curr_pt[0] += W
    #         color = np.random.randint(0, 255, 3)
    #         color = (int(color[0]), int(color[1]), int(color[2]))
    #
    #         matches_img = cv2.line(matches_img, prev_pt, curr_pt, tuple(color), 1, cv2.LINE_AA)
    #         matches_img = cv2.circle(matches_img, prev_pt, 2, tuple(color), -1)
    #         matches_img = cv2.circle(matches_img, curr_pt, 2, tuple(color), -1)
    #
    #     plt.figure()
    #     plt.imshow(matches_img)
    #     plt.show()

    # Find rigid matrix
    if prevPoints.shape[0] > 4:
        H, inliers = cv2.estimateAffinePartial2D(prevPoints, currPoints, cv2.RANSAC)

        # Handle downscale
        if self.downscale > 1.0:
            H[0, 2] *= self.downscale
            H[1, 2] *= self.downscale
    else:
        LOGGER.warning("WARNING: not enough matching points")

    # Store to next iteration
    self.prevFrame = frame.copy()
    self.prevKeyPoints = copy.copy(keypoints)
    self.prevDescriptors = copy.copy(descriptors)

    return H

applySparseOptFlow(raw_frame)

Applica il metodo Sparse Optical Flow a un fotogramma grezzo.

Parametri:

Nome Tipo Descrizione Predefinito
raw_frame ndarray

Il fotogramma grezzo da elaborare.

richiesto

Restituzione:

Tipo Descrizione
ndarray

Cornice elaborata.

Esempi:

>>> gmc = GMC()
>>> gmc.applySparseOptFlow(np.array([[1, 2, 3], [4, 5, 6]]))
array([[1, 2, 3],
       [4, 5, 6]])
Codice sorgente in ultralytics/trackers/utils/gmc.py
def applySparseOptFlow(self, raw_frame: np.array) -> np.array:
    """
    Apply Sparse Optical Flow method to a raw frame.

    Args:
        raw_frame (np.ndarray): The raw frame to be processed.

    Returns:
        (np.ndarray): Processed frame.

    Examples:
        >>> gmc = GMC()
        >>> gmc.applySparseOptFlow(np.array([[1, 2, 3], [4, 5, 6]]))
        array([[1, 2, 3],
               [4, 5, 6]])
    """
    height, width, _ = raw_frame.shape
    frame = cv2.cvtColor(raw_frame, cv2.COLOR_BGR2GRAY)
    H = np.eye(2, 3)

    # Downscale image
    if self.downscale > 1.0:
        frame = cv2.resize(frame, (width // self.downscale, height // self.downscale))

    # Find the keypoints
    keypoints = cv2.goodFeaturesToTrack(frame, mask=None, **self.feature_params)

    # Handle first frame
    if not self.initializedFirstFrame or self.prevKeyPoints is None:
        self.prevFrame = frame.copy()
        self.prevKeyPoints = copy.copy(keypoints)
        self.initializedFirstFrame = True
        return H

    # Find correspondences
    matchedKeypoints, status, _ = cv2.calcOpticalFlowPyrLK(self.prevFrame, frame, self.prevKeyPoints, None)

    # Leave good correspondences only
    prevPoints = []
    currPoints = []

    for i in range(len(status)):
        if status[i]:
            prevPoints.append(self.prevKeyPoints[i])
            currPoints.append(matchedKeypoints[i])

    prevPoints = np.array(prevPoints)
    currPoints = np.array(currPoints)

    # Find rigid matrix
    if (prevPoints.shape[0] > 4) and (prevPoints.shape[0] == prevPoints.shape[0]):
        H, _ = cv2.estimateAffinePartial2D(prevPoints, currPoints, cv2.RANSAC)

        if self.downscale > 1.0:
            H[0, 2] *= self.downscale
            H[1, 2] *= self.downscale
    else:
        LOGGER.warning("WARNING: not enough matching points")

    self.prevFrame = frame.copy()
    self.prevKeyPoints = copy.copy(keypoints)

    return H

reset_params()

Azzera i parametri.

Codice sorgente in ultralytics/trackers/utils/gmc.py
def reset_params(self) -> None:
    """Reset parameters."""
    self.prevFrame = None
    self.prevKeyPoints = None
    self.prevDescriptors = None
    self.initializedFirstFrame = False





Created 2023-11-12, Updated 2024-06-02
Authors: glenn-jocher (5), Burhan-Q (1)