小编nao*_*ity的帖子

当我训练 UNET 时，dice coef 和 iou 有时会变得大于 1 和iou > dice，然后经过几个批次后它们又会恢复正常。如图所示。

我将它们定义如下：

def dice_coef(y_true, y_pred, smooth=1):
    y_true_f = K.flatten(y_true)
    y_pred_f = K.flatten(y_pred)
    intersection = K.sum(y_true_f * y_pred_f)
    return (2. * intersection + smooth) / (K.sum(y_true_f) + K.sum(y_pred_f) + smooth)

def iou(y_true, y_pred, smooth=1):
    y_true_f = K.flatten(y_true)
    y_pred_f = K.flatten(y_pred)
    intersection = K.sum(y_true_f * y_pred_f)
    union = K.sum(y_true_f) + K.sum(y_pred_f) - intersection
    return (intersection + smooth) / (union + smooth)

def dice_loss(y_true, y_pred):
    return 1. - dice_coef(y_true, …