使用Matplolib在python中使用多处理功能保存多个图像(〜50k)

时间:2019-06-13 14:45:20

标签: python image matplotlib audio google-colaboratory

我已经在Code review StackExchange中将问题发布到了这里(仅用于代码审查),但是无法获得答案,所以我在这里对我的问题非常具体。 下面的代码遍历音频文件的目录(约50k),并将它们转换为声谱图图像,并将它们保存在同一顶级目录中。

def plot_and_save(denoised_data, f_name):
    fig, ax = plt.subplots()

    i = 0
    # Add this line to show plots else ignore warnings
    # plt.ion()

    ax.imshow(denoised_data)

    ax.get_xaxis().set_visible(False)
    ax.get_yaxis().set_visible(False)
    fig.set_size_inches(10, 10)
    fig.savefig(
        f"{f_name}" + "_{:04d}.png".format(i),
        dpi=80,
        bbox_inches="tight",
        quality=95,
        pad_inches=0.0)

    ax.draw_artist(ax.xaxis)
    ax.draw_artist(ax.yaxis)

    i += 1


def standardize_and_plot(sampling_rate, file_path_image):
    logger.info(f"All files will be resampled to {sampling_rate}Hz")

    output_image_folder = "PreProcessed_image/"

    for dirs, subdirs, files in os.walk(file_path_image):
        for i, file in enumerate(files):
            if file.endswith(('.wav', '.WAV')):
                logger.info(f"Pre-Processing file: {file}")
                data, sr = librosa.core.load(
                    os.path.join(dirs, file), sr=sampling_rate, res_type='kaiser_fast')
                target_path = os.path.join(output_image_folder, dirs)

                pcen_S = apply_per_channel_energy_norm(data, sr)

                denoised_data = wavelet_denoising(pcen_S)

                work_dir = os.getcwd()

                if not os.path.exists(target_path):
                    os.makedirs(target_path)

                os.chdir(target_path)

                f_name, _ = os.path.splitext(os.path.basename(file))

                plot_and_save(denoised_data, f_name)

                os.chdir(work_dir)

if __name__ == '__main__':
    chunkSize = 3
    sampling_rate = 44100
    file_path_audio = 'Recordings'
    file_path_audio = "data/"
    output_audio_folder = "PreProcessed_audio/"

    file_path_image = os.path.join(output_audio_folder, file_path_audio)

    standardize_and_plot(sampling_rate, file_path_image)

如何通过使用多重处理来优化plot_and_save()方法?将那么多图像保存在磁盘上需要花费大量时间。我正在为此目的使用Google Colab。

1 个答案:

答案 0 :(得分:2)

您尝试这样的事情:

from joblib import Parallel, delayed

chunkSize = 3
sampling_rate = 44100
file_path_audio = 'Recordings'
file_path_audio = "data/"
output_audio_folder = "PreProcessed_audio/"



def process_and_save(filename):
    data, sr = librosa.core.load(filename, sr=sampling_rate, res_type='kaiser_fast')
    target_path = os.path.join(output_image_folder, dirs)

    pcen_S = apply_per_channel_energy_norm(data, sr)

    denoised_data = wavelet_denoising(pcen_S)

    work_dir = os.getcwd()

    if not os.path.exists(target_path):
        os.makedirs(target_path)

    os.chdir(target_path)

    f_name, _ = os.path.splitext(os.path.basename(file))

    fig, ax = plt.subplots()

    i = 0
    # Add this line to show plots else ignore warnings
    # plt.ion()

    ax.imshow(denoised_data)

    ax.get_xaxis().set_visible(False)
    ax.get_yaxis().set_visible(False)
    fig.set_size_inches(10, 10)
    fig.savefig(
        f"{f_name}" + "_{:04d}.png".format(i),
        dpi=80,
        bbox_inches="tight",
        quality=95,
        pad_inches=0.0)
    ax.draw_artist(ax.xaxis)
    ax.draw_artist(ax.yaxis)
    i += 1


wav_files = []
for dirs, subdirs, files in os.walk(file_path_image):
    for i, file in enumerate(files):
        if file.endswith(('.wav', '.WAV')):
            wav_files.append(os.path.join(dirs, file))

Parallel(n_jobs=4, backend='multiprocessing')(delayed(process_and_save)(w) for w in wav_files)

未经测试。您可能需要修复一些问题才能使其正常工作。