def calc_detection_voc_prec_rec()

in FasterRCNNDetection/utils/eval_tool.py [0:0]


def calc_detection_voc_prec_rec(
        pred_bboxes, pred_labels, pred_scores, gt_bboxes, gt_labels,
        gt_difficults=None,
        iou_thresh=0.5):
    """Calculate precision and recall based on evaluation code of PASCAL VOC.

    This function calculates precision and recall of
    predicted bounding boxes obtained from a dataset which has :math:`N`
    images.
    The code is based on the evaluation code used in PASCAL VOC Challenge.

    Args:
        pred_bboxes (iterable of numpy.ndarray): An iterable of :math:`N`
            sets of bounding boxes.
            Its index corresponds to an index for the base dataset.
            Each element of :obj:`pred_bboxes` is a set of coordinates
            of bounding boxes. This is an array whose shape is :math:`(R, 4)`,
            where :math:`R` corresponds
            to the number of bounding boxes, which may vary among boxes.
            The second axis corresponds to
            :math:`y_{min}, x_{min}, y_{max}, x_{max}` of a bounding box.
        pred_labels (iterable of numpy.ndarray): An iterable of labels.
            Similar to :obj:`pred_bboxes`, its index corresponds to an
            index for the base dataset. Its length is :math:`N`.
        pred_scores (iterable of numpy.ndarray): An iterable of confidence
            scores for predicted bounding boxes. Similar to :obj:`pred_bboxes`,
            its index corresponds to an index for the base dataset.
            Its length is :math:`N`.
        gt_bboxes (iterable of numpy.ndarray): An iterable of ground truth
            bounding boxes
            whose length is :math:`N`. An element of :obj:`gt_bboxes` is a
            bounding box whose shape is :math:`(R, 4)`. Note that the number of
            bounding boxes in each image does not need to be same as the number
            of corresponding predicted boxes.
        gt_labels (iterable of numpy.ndarray): An iterable of ground truth
            labels which are organized similarly to :obj:`gt_bboxes`.
        gt_difficults (iterable of numpy.ndarray): An iterable of boolean
            arrays which is organized similarly to :obj:`gt_bboxes`.
            This tells whether the
            corresponding ground truth bounding box is difficult or not.
            By default, this is :obj:`None`. In that case, this function
            considers all bounding boxes to be not difficult.
        iou_thresh (float): A prediction is correct if its Intersection over
            Union with the ground truth is above this value..

    Returns:
        tuple of two lists:
        This function returns two lists: :obj:`prec` and :obj:`rec`.

        * :obj:`prec`: A list of arrays. :obj:`prec[l]` is precision \
            for class :math:`l`. If class :math:`l` does not exist in \
            either :obj:`pred_labels` or :obj:`gt_labels`, :obj:`prec[l]` is \
            set to :obj:`None`.
        * :obj:`rec`: A list of arrays. :obj:`rec[l]` is recall \
            for class :math:`l`. If class :math:`l` that is not marked as \
            difficult does not exist in \
            :obj:`gt_labels`, :obj:`rec[l]` is \
            set to :obj:`None`.

    """
    #print(pred_scores)
    #print(len(pred_bboxes),len(pred_labels),len(pred_scores),len(gt_bboxes),len(gt_labels),len(gt_difficults))
    pred_bboxes = iter(pred_bboxes)
    pred_labels = iter(pred_labels)
    pred_scores = iter(pred_scores)
    gt_bboxes = iter(gt_bboxes)
    gt_labels = iter(gt_labels)
    gt_difficults = itertools.repeat(None) #need to figure out why gt_difficults is the wrong length
    #if gt_difficults is None:
    #    gt_difficults = itertools.repeat(None)
    #else:
    #    gt_difficults = iter(gt_difficults)

    n_pos = defaultdict(int)
    score = defaultdict(list)
    match = defaultdict(list)
    
    for pred_bbox, pred_label, pred_score, gt_bbox, gt_label, gt_difficult in \
            six.moves.zip(
                pred_bboxes, pred_labels, pred_scores,
                gt_bboxes, gt_labels, gt_difficults):
        
        if gt_difficult is None:
            gt_difficult = np.zeros(len(gt_bbox), dtype=bool)

        for l in np.unique(np.concatenate((pred_label, gt_label)).astype(int)):
            
            pred_mask_l = pred_label == l
            pred_bbox_l = pred_bbox[pred_mask_l]
            pred_score_l = pred_score[pred_mask_l]
            # sort by score
            order = pred_score_l.argsort()[::-1]
            pred_bbox_l = pred_bbox_l[order]
            pred_score_l = pred_score_l[order]

            gt_mask_l = [i for i in range(len(gt_label)) if gt_label[i] == l]
            
            if len(gt_bbox) > 0:
                gt_bbox_l =  np.asarray([gt_bbox[i] for i in gt_mask_l])
            else:
                gt_bbox_l = []
            
            gt_difficult_l = gt_difficult[gt_mask_l]
            n_pos[l] += np.logical_not(gt_difficult_l).sum()
            score[l].extend(pred_score_l)

            if len(pred_bbox_l) == 0:
                continue
            if len(gt_bbox_l) == 0:
                match[l].extend((0,) * pred_bbox_l.shape[0])

                continue

            # VOC evaluation follows integer typed bounding boxes.
            
            pred_bbox_l = pred_bbox_l.copy()
            pred_bbox_l[:, 2:] += 1
            
            gt_bbox_l = gt_bbox_l.copy()
            gt_bbox_l[:, 2:] += 1

            
            iou = bbox_iou(pred_bbox_l, gt_bbox_l)
            gt_index = iou.argmax(axis=1)
            # set -1 if there is no matching ground truth
            gt_index[iou.max(axis=1) < iou_thresh] = -1
            del iou
            #print(gt_index)

            selec = np.zeros(gt_bbox_l.shape[0], dtype=bool)
            for gt_idx in gt_index:
                if gt_idx >= 0:
                    if gt_difficult_l[gt_idx]:
                        match[l].append(-1)
                    else:
                        if not selec[gt_idx]:
                            match[l].append(1)
                        else:
                            match[l].append(0)
                    selec[gt_idx] = True
                else:
                    match[l].append(0)
    
    for iter_ in (
            pred_bboxes, pred_labels, pred_scores,
            gt_bboxes, gt_labels, gt_difficults):
        if next(iter_, None) is not None:
            raise ValueError('Length of input iterables need to be same.')

    n_fg_class = max(n_pos.keys()) + 1
    prec = [None] * n_fg_class
    rec = [None] * n_fg_class
    
    for l in n_pos.keys():
        score_l = np.array(score[l])
        match_l = np.array(match[l], dtype=np.int8)
        order = score_l.argsort()[::-1]
        match_l = match_l[order]
        tp = np.cumsum(match_l == 1)
        fp = np.cumsum(match_l == 0)

        # If an element of fp + tp is 0,
        # the corresponding element of prec[l] is nan.
        prec[l] = tp / (fp + tp)
        # If n_pos[l] is 0, rec[l] is None.
        if n_pos[l] > 0:
            rec[l] = tp / n_pos[l]
    #rec = [i.numpy() for i in rec if i is not None]
    return prec, rec