3
這是Keras初始版v3的預處理功能。它與其他模型預處理完全不同。Keras初始版v3的預處理功能
def preprocess_input(x):
x /= 255.
x -= 0.5
x *= 2.
return x
1.爲什麼沒有均值減法?
2.爲什麼沒有RGB到BGR?
3.此模型[-1,1]之間的映射是否正常?
,這是預處理VGG和RESNET的功能Keras:
def preprocess_input(x, data_format=None):
if data_format is None:
data_format = K.image_data_format()
assert data_format in {'channels_last', 'channels_first'}
if data_format == 'channels_first':
# 'RGB'->'BGR'
x = x[:, ::-1, :, :]
# Zero-center by mean pixel
x[:, 0, :, :] -= 103.939
x[:, 1, :, :] -= 116.779
x[:, 2, :, :] -= 123.68
else:
# 'RGB'->'BGR'
x = x[:, :, :, ::-1]
# Zero-center by mean pixel
x[:, :, :, 0] -= 103.939
x[:, :, :, 1] -= 116.779
x[:, :, :, 2] -= 123.68
return x
而且來自Caffe車型使用平均減法和RGB到BGR。