問題描述

speech recognize是kaggle上1，2年前的一個賽題，主要描述的是如果在各種環境中識別出簡單的英文單詞發音，比如bed，cat，right之類的語音。提供的訓練集是.wav格式的語音，解壓后數據集大小在2G左右。

訓練集分析

語音識別相對圖片識別來說，是一個區別較大的領域。所以首先要了解訓練集的基本特征，理清不同語音之間的共性。

振幅和頻率

def log_specgram(audio, sample_rate, window_size=20,

step_size=10, eps=1e-10):

nperseg = int(round(window_size * sample_rate / 1e3))

noverlap = int(round(step_size * sample_rate / 1e3))

freqs, times, spec = signal.spectrogram(audio,

fs=sample_rate,

window='hann',

nperseg=nperseg,

noverlap=noverlap,

detrend=False)

return freqs, times, np.log(spec.T.astype(np.float32) + eps)

def plt_specgram(freqs, times, spectrogram):

fig = plt.figure(figsize=(14, 8))

ax1 = fig.add_subplot(211)

ax1.set_title('Raw wave of ' + filename)

ax1.set_ylabel('Amplitude')

ax1.plot(np.linspace(0, sample_rate / len(samples), sample_rate), samples)

ax2 = fig.add_subplot(212)

ax2.imshow(spectrogram.T, aspect='auto', origin='lower',

extent=[times.min(), times.max(), freqs.min(), freqs.max()])

ax2.set_yticks(freqs[::16])

ax2.set_xticks(times[::16])

ax2.set_title('Spectrogram of ' + filename)

ax2.set_ylabel('Freqs in Hz')

ax2.set_xlabel('Seconds')

plt.savefig('./output/yes_0a7c2a8d_nohash_0.png')

plt.show()

train_audio_path = './input/train/audio/'

filename = '/yes/0a7c2a8d_nohash_0.wav'

sample_rate, samples = wavfile.read(str(train_audio_path) + filename)

# print(sample_rate, samples)

# 頻譜圖

freqs, times, spectrogram = log_specgram(samples, sample_rate)

plt_specgram(freqs, times, spectrogram)

聲音強度

def plt_spectrogram():

plt.figure(figsize=(12, 4))

librosa.display.specshow(log_S, sr=sample_rate, x_axis='time', y_axis='mel')

plt.title('Mel power spectrogram ')

plt.colorbar(format='%+02.0f dB')

plt.tight_layout()

plt.savefig('./output/spectrogram.png')

plt.show()

# 光譜圖

sig = samples

sig = sig / max(abs(sig))

S = librosa.feature.melspectrogram(y=sig, sr=sample_rate, n_mels=128)

log_S = librosa.power_to_db(S, ref=np.max)

plt_spectrogram()

三維圖像

def spectrogram_3d():

data = [go.Surface(z=spectrogram.T)]

layout = go.Layout(

title='Specgtrogram of "yes" in 3d',

scene=dict(

yaxis=dict(title='Frequencies'),

xaxis=dict(title='Time'),

zaxis=dict(title='Log amplitude'),

),

)

fig = go.Figure(data=data, layout=layout)

py.plot(fig)

spectrogram_3d()

不同音頻的總數統計

def count_summary():

dirs.sort()

print('Number of labels: ' + str(len(dirs)))

number_of_recordings = []

for direct in dirs:

waves = [f for f in os.listdir(join(train_audio_path, direct)) if f.endswith('.wav')]

number_of_recordings.append(len(waves))

speech_count = dict(map(lambda x, y: [x, y], dirs, number_of_recordings))

print(speech_count)

count_summary()

"""輸出

{'_background_noise_': 6, 'bed': 1713, 'bird': 1731, 'cat': 1733, 'dog': 1746, 'down': 2359, 'eight': 2352, 'five': 2357, 'four': 2372, 'go': 2372, 'happy': 1742, 'house': 1750, 'left': 2353, 'marvin': 1746, 'nine': 2364, 'no': 2375, 'off': 2357, 'on': 2367, 'one': 2370, 'right': 2367, 'seven': 2377, 'sheila': 1734, 'six': 2369, 'stop': 2380, 'three': 2356, 'tree': 1733, 'two': 2373, 'up': 2375, 'wow': 1745, 'yes': 2377, 'zero': 2376}

"""

每個英文發音的特征識別

def mean_fft():

to_keep = 'yes no up down left right on off stop go'.split()

dir = [d for d in dirs if d in to_keep]

print(dir)

for direct in dir:

vals_all = []

spec_all = []

waves = [f for f in os.listdir(join(train_audio_path, direct)) if f.endswith('.wav')]

for wav in waves:

sample_rate, samples = wavfile.read(train_audio_path + direct + '/' + wav)

if samples.shape[0] != 16000:

continue

xf, vals = custom_fft(samples, 16000)

vals_all.append(vals)

freqs, times, spec = log_specgram(samples, 16000)

spec_all.append(spec)

plt.figure(figsize=(14, 4))

plt.subplot(121)

plt.title('Mean fft of ' + direct)

plt.plot(np.mean(np.array(vals_all), axis=0))

plt.grid()

plt.subplot(122)

plt.title('Mean specgram of ' + direct)

plt.imshow(np.mean(np.array(spec_all), axis=0).T, aspect='auto', origin='lower',

extent=[times.min(), times.max(), freqs.min(), freqs.max()])

plt.yticks(freqs[::16])

plt.xticks(times[::16])

plt.savefig('./output/mean_fft_' + direct + '.png')

plt.show()

mean_fft()

代碼是把所有英文單詞的特征圖都輸出，這里只展示down和yes，2個特征圖

原始數據處理

for label, fname in zip(labels, fnames):

sample_rate, samples = wavfile.read(os.path.join(train_data_path, label, fname))

samples = pad_audio(samples)

if len(samples) > 16000:

n_samples = chop_audio(samples)

else:

n_samples = [samples]

for samples in n_samples:

resampled = signal.resample(samples, int(new_sample_rate / sample_rate * samples.shape[0]))

_, _, specgram = log_specgram(resampled, sample_rate=new_sample_rate)

y_train.append(label)

x_train.append(specgram)

x_train = np.array(x_train)

x_train = x_train.reshape(tuple(list(x_train.shape) + [1]))

y_train = label_transform(y_train)

label_index = y_train.columns.values

y_train = y_train.values

y_train = np.array(y_train)

del labels, fnames

gc.collect()

cnn建模

def model_cnn(x_train, y_train):

input_shape = (99, 81, 1)

nclass = 12

inp = Input(shape=input_shape)

norm_inp = BatchNormalization()(inp)

img_1 = Convolution2D(8, kernel_size=2, activation=activations.relu)(norm_inp)

img_1 = Convolution2D(8, kernel_size=2, activation=activations.relu)(img_1)

img_1 = MaxPooling2D(pool_size=(2, 2))(img_1)

img_1 = Dropout(rate=0.2)(img_1)

img_1 = Convolution2D(16, kernel_size=3, activation=activations.relu)(img_1)

img_1 = Convolution2D(16, kernel_size=3, activation=activations.relu)(img_1)

img_1 = MaxPooling2D(pool_size=(2, 2))(img_1)

img_1 = Dropout(rate=0.2)(img_1)

img_1 = Convolution2D(32, kernel_size=3, activation=activations.relu)(img_1)

img_1 = MaxPooling2D(pool_size=(2, 2))(img_1)

img_1 = Dropout(rate=0.2)(img_1)

img_1 = Flatten()(img_1)

dense_1 = BatchNormalization()(Dense(128, activation=activations.relu)(img_1))

dense_1 = BatchNormalization()(Dense(128, activation=activations.relu)(dense_1))

dense_1 = Dense(nclass, activation=activations.softmax)(dense_1)

model = models.Model(inputs=inp, outputs=dense_1)

opt = optimizers.Adam()

model.compile(optimizer=opt, loss=losses.binary_crossentropy)

model.summary()

x_train, x_valid, y_train, y_valid = train_test_split(x_train, y_train, test_size=0.1, random_state=2017)

model.fit(x_train, y_train, batch_size=16, validation_data=(x_valid, y_valid), epochs=3, shuffle=True, verbose=2)

model.save(os.path.join(model_path, 'cnn.model'))

return model

model = model_cnn(x_train, y_train)

"""輸出

Using TensorFlow backend.

2019-06-15 20:59:45.453845 task begin

./input/train/audio

2019-06-15 20:59:46.634215 xy begin

/Users/user/Library/Python/3.6/lib/python/site-packages/scipy/io/wavfile.py:273: WavFileWarning: Chunk (non-data) not understood, skipping it.

WavFileWarning)

2019-06-15 21:02:35.116550 reshape begin

2019-06-15 21:02:46.166546 model begin

WARNING:tensorflow:From /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py:263: colocate_with (from tensorflow.python.framework.ops) is deprecated and will be removed in a future version.

Instructions for updating:

Colocations handled automatically by placer.

2019-06-15 21:02:46.278603: I tensorflow/core/platform/cpu_feature_guard.cc:141] Your CPU supports instructions that this TensorFlow binary was not compiled to use: AVX2 FMA

_________________________________________________________________

Layer (type) Output Shape Param #

=================================================================

input_1 (InputLayer) (None, 99, 81, 1) 0

_________________________________________________________________

batch_normalization_1 (Batch (None, 99, 81, 1) 4

_________________________________________________________________

conv2d_1 (Conv2D) (None, 98, 80, 8) 40

_________________________________________________________________

conv2d_2 (Conv2D) (None, 97, 79, 8) 264

_________________________________________________________________

max_pooling2d_1 (MaxPooling2 (None, 48, 39, 8) 0

_________________________________________________________________

dropout_1 (Dropout) (None, 48, 39, 8) 0

_________________________________________________________________

conv2d_3 (Conv2D) (None, 46, 37, 16) 1168

_________________________________________________________________

conv2d_4 (Conv2D) (None, 44, 35, 16) 2320

_________________________________________________________________

max_pooling2d_2 (MaxPooling2 (None, 22, 17, 16) 0

_________________________________________________________________

dropout_2 (Dropout) (None, 22, 17, 16) 0

_________________________________________________________________

conv2d_5 (Conv2D) (None, 20, 15, 32) 4640

_________________________________________________________________

max_pooling2d_3 (MaxPooling2 (None, 10, 7, 32) 0

_________________________________________________________________

dropout_3 (Dropout) (None, 10, 7, 32) 0

_________________________________________________________________

flatten_1 (Flatten) (None, 2240) 0

_________________________________________________________________

dense_1 (Dense) (None, 128) 286848

_________________________________________________________________

batch_normalization_2 (Batch (None, 128) 512

_________________________________________________________________

dense_2 (Dense) (None, 128) 16512

_________________________________________________________________

batch_normalization_3 (Batch (None, 128) 512

_________________________________________________________________

dense_3 (Dense) (None, 12) 1548

=================================================================

Total params: 314,368

Trainable params: 313,854

Non-trainable params: 514

_________________________________________________________________

Instructions for updating:

Use tf.cast instead.

Train on 58356 samples, validate on 6485 samples

Epoch 1/3

- 737s - loss: 0.1415 - val_loss: 0.0874

Epoch 2/3

- 608s - loss: 0.0807 - val_loss: 0.0577

Epoch 3/3

- 518s - loss: 0.0636 - val_loss: 0.0499

2019-06-15 21:33:58.518621 predict begin

"""

預測

del x_train, y_train

gc.collect()

index = []

results = []

for fnames, imgs in test_data_generator(batch=32):

predicts = model.predict(imgs)

predicts = np.argmax(predicts, axis=1)

predicts = [label_index[p] for p in predicts]

index.extend(fnames)

results.extend(predicts)

df = pd.DataFrame(columns=['fname', 'label'])

df['fname'] = index

df['label'] = results

df.to_csv(os.path.join(out_path, 'sub.csv'), index=False)

關于預測的數據集，kaggle提供的壓縮包有2，3G，解壓后有將近10w條音頻，個人筆記本吃不消。于是只選取其中的100條來測試，根據預測出的結果，和自己聽取wav音頻的結果對比，是正確的。但是并沒有在大規模的數據集上預測，所以準確率不可知。后續在GPU上訓練時，再考慮預測所有的數據。

完整代碼下載

總結

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