Slow non max suppression

[Source82]

Hi,

Thanks for the great work.

Unfortunately nonmaxsuppression makes the tensorrt implementation so slow.

Thanks

[Source82]

I will suggest you change the current nms with this

def faster_nms(boxes, scores, nms_thresh):
        x1 = boxes[:, 0]
        y1 = boxes[:, 1]
        x2 = boxes[:, 2]
        y2 = boxes[:, 3]
        areas = (x2 - x1 + 1) * (y2 - y1 + 1)
        order = np.argsort(scores)[::-1]
        num_detections = boxes.shape[0]
        suppressed = np.zeros((num_detections,), dtype=np.bool)

        keep = []
        while order.size > 0:
            i = order[0]
            keep.append(i)
            xx1 = np.maximum(x1[i], x1[order[1:]])
            yy1 = np.maximum(y1[i], y1[order[1:]])
            xx2 = np.minimum(x2[i], x2[order[1:]])
            yy2 = np.minimum(y2[i], y2[order[1:]])

            w = np.maximum(0.0, xx2 - xx1 + 1)
            h = np.maximum(0.0, yy2 - yy1 + 1)
            inter = w * h
            ovr = inter / (areas[i] + areas[order[1:]] - inter)

            inds = np.where(ovr <= nms_thresh)[0]
            order = order[inds + 1]

        return keep