densenet.py 文件源码

def __transition_up_block(ip, nb_filters, type='deconv', weight_decay=1E-4):
    ''' SubpixelConvolutional Upscaling (factor = 2)
    Args:
        ip: keras tensor
        nb_filters: number of layers
        type: can be 'upsampling', 'subpixel', 'deconv'. Determines type of upsampling performed
        weight_decay: weight decay factor
    Returns: keras tensor, after applying upsampling operation.
    '''

    if type == 'upsampling':
        x = UpSampling2D()(ip)
    elif type == 'subpixel':
        x = Conv2D(nb_filters, (3, 3), activation='relu', padding='same', kernel_regularizer=l2(weight_decay),
                   use_bias=False, kernel_initializer='he_normal')(ip)
        x = SubPixelUpscaling(scale_factor=2)(x)
        x = Conv2D(nb_filters, (3, 3), activation='relu', padding='same', kernel_regularizer=l2(weight_decay),
                   use_bias=False, kernel_initializer='he_normal')(x)
    else:
        x = Conv2DTranspose(nb_filters, (3, 3), activation='relu', padding='same', strides=(2, 2),
                            kernel_initializer='he_normal', kernel_regularizer=l2(weight_decay))(ip)

    return x