def eval_map()

in models/vision/detection/awsdet/core/evaluation/mean_ap.py [0:0]


def eval_map(det_results,
             annotations,
             scale_ranges=None,
             iou_thr=0.5,
             dataset=None,
             logger=None,
             nproc=4):
    """Evaluate mAP of a dataset.

    Args:
        det_results (list[list]): [[cls1_det, cls2_det, ...], ...].
            The outer list indicates images, and the inner list indicates
            per-class detected bboxes.
        annotations (list[dict]): Ground truth annotations where each item of
            the list indicates an image. Keys of annotations are:
                - "bboxes": numpy array of shape (n, 4)
                - "labels": numpy array of shape (n, )
                - "bboxes_ignore" (optional): numpy array of shape (k, 4)
                - "labels_ignore" (optional): numpy array of shape (k, )
        scale_ranges (list[tuple] | None): Range of scales to be evaluated,
            in the format [(min1, max1), (min2, max2), ...]. A range of
            (32, 64) means the area range between (32**2, 64**2).
            Default: None.
        iou_thr (float): IoU threshold to be considered as matched.
            Default: 0.5.
        dataset (list[str] | str | None): Dataset name or dataset classes,
            there are minor differences in metrics for different datsets, e.g.
            "voc07", "imagenet_det", etc. Default: None.
        logger (logging.Logger | str | None): The way to print the mAP
            summary. See `awsdet.utils.print_log()` for details. Default: None.
        nproc (int): Processes used for computing TP and FP.
            Default: 4.

    Returns:
        tuple: (mAP, [dict, dict, ...])
    """
    assert len(det_results) == len(annotations)

    num_imgs = len(det_results)
    num_scales = len(scale_ranges) if scale_ranges is not None else 1
    num_classes = len(det_results[0])  # positive class num
    area_ranges = ([(rg[0]**2, rg[1]**2) for rg in scale_ranges]
                   if scale_ranges is not None else None)

    pool = Pool(nproc)
    eval_results = []
    for i in range(num_classes):
        # get gt and det bboxes of this class
        cls_dets, cls_gts, cls_gts_ignore = get_cls_results(
            det_results, annotations, i)
        # choose proper function according to datasets to compute tp and fp
        if dataset in ['det', 'vid']:
            tpfp_func = tpfp_imagenet
        else:
            tpfp_func = tpfp_default
        # compute tp and fp for each image with multiple processes
        tpfp = pool.starmap(
            tpfp_func,
            zip(cls_dets, cls_gts, cls_gts_ignore,
                [iou_thr for _ in range(num_imgs)],
                [area_ranges for _ in range(num_imgs)]))
        tp, fp = tuple(zip(*tpfp))
        # calculate gt number of each scale
        # ignored gts or gts beyond the specific scale are not counted
        num_gts = np.zeros(num_scales, dtype=int)
        for j, bbox in enumerate(cls_gts):
            if area_ranges is None:
                num_gts[0] += bbox.shape[0]
            else:
                gt_areas = (bbox[:, 2] - bbox[:, 0]) * (
                    bbox[:, 3] - bbox[:, 1])
                for k, (min_area, max_area) in enumerate(area_ranges):
                    num_gts[k] += np.sum((gt_areas >= min_area)
                                         & (gt_areas < max_area))
        # sort all det bboxes by score, also sort tp and fp
        cls_dets = np.vstack(cls_dets)
        num_dets = cls_dets.shape[0]
        sort_inds = np.argsort(-cls_dets[:, -1])
        tp = np.hstack(tp)[:, sort_inds]
        fp = np.hstack(fp)[:, sort_inds]
        # calculate recall and precision with tp and fp
        tp = np.cumsum(tp, axis=1)
        fp = np.cumsum(fp, axis=1)
        eps = np.finfo(np.float32).eps
        recalls = tp / np.maximum(num_gts[:, np.newaxis], eps)
        precisions = tp / np.maximum((tp + fp), eps)
        # calculate AP
        if scale_ranges is None:
            recalls = recalls[0, :]
            precisions = precisions[0, :]
            num_gts = num_gts.item()
        mode = 'area' if dataset != 'voc07' else '11points'
        ap = average_precision(recalls, precisions, mode)
        eval_results.append({
            'num_gts': num_gts,
            'num_dets': num_dets,
            'recall': recalls,
            'precision': precisions,
            'ap': ap
        })
    if scale_ranges is not None:
        # shape (num_classes, num_scales)
        all_ap = np.vstack([cls_result['ap'] for cls_result in eval_results])
        all_num_gts = np.vstack(
            [cls_result['num_gts'] for cls_result in eval_results])
        mean_ap = []
        for i in range(num_scales):
            if np.any(all_num_gts[:, i] > 0):
                mean_ap.append(all_ap[all_num_gts[:, i] > 0, i].mean())
            else:
                mean_ap.append(0.0)
    else:
        aps = []
        for cls_result in eval_results:
            if cls_result['num_gts'] > 0:
                aps.append(cls_result['ap'])
        mean_ap = np.array(aps).mean().item() if aps else 0.0

    print_map_summary(
        mean_ap, eval_results, dataset, area_ranges, logger=logger)

    return mean_ap, eval_results