巨蟒分贝计-准确吗？

Question

import os, errno
import pyaudio
from scipy.signal import lfilter
import numpy
from tkinter import *
from tkinter.ttk import *
from tk_tools import *
from tkinter import messagebox
root=Tk()
root.title('Decibel Meter')
root.grid()
gaugedb = RotaryScale(root, max_value=120.0, unit=' dBA')
gaugedb.grid(column=1, row=1)
led = Led(root, size=50)
led.grid(column=3, row=1)
led.to_red(on=False)
Label(root, text='Too Loud').grid(column=3, row=0)
Label(root, text='Max').grid(column=2, row=0)
Label(root, text='Calibration (dB)').grid(column=4, row=0)
maxdb_display=SevenSegmentDigits(root, digits=3, digit_color='#00ff00', background='black')
maxdb_display.grid(column=2, row=1)
CHUNKS = [4096, 9600]
CHUNK = CHUNKS[1]
FORMAT = pyaudio.paInt16
CHANNEL = 1 
RATES = [44300, 48000]
RATE = RATES[1]
offset=StringVar()
offset.set('0')
spinbox=Spinbox(root, from_=-20, to=20, textvariable=offset, state='readonly')
spinbox.grid(column=4, row=1)
appclosed=False
from scipy.signal import bilinear
def close():
 global appclosed
 root.destroy()
 appclosed=True
 stream.stop_stream()
 stream.close()
 pa.terminate()
def A_weighting(fs):
 f1 = 20.598997
 f2 = 107.65265
 f3 = 737.86223
 f4 = 12194.217
 A1000 = 1.9997

 NUMs = [(2*numpy.pi * f4)**2 * (10**(A1000/20)), 0, 0, 0, 0]
 DENs = numpy.polymul([1, 4*numpy.pi * f4, (2*numpy.pi * f4)**2],
                [1, 4*numpy.pi * f1, (2*numpy.pi * f1)**2])
 DENs = numpy.polymul(numpy.polymul(DENs, [1, 2*numpy.pi * f3]),
                              [1, 2*numpy.pi * f2])
 return bilinear(NUMs, DENs, fs)
NUMERATOR, DENOMINATOR = A_weighting(RATE)
def rms_flat(a):
 return numpy.sqrt(numpy.mean(numpy.absolute(a)**2))
pa = pyaudio.PyAudio()
stream = pa.open(format = FORMAT,
             channels = CHANNEL,
             rate = RATE,
             input = True,
             frames_per_buffer = CHUNK)
def update_max_if_new_is_larger_than_max(new, max):
 if new > max:
     return new
 else:
     return max
def listen(old=0, error_count=0, min_decibel=100, max_decibel=0):
 global appclosed
 while True:
     try:
         try:
             block = stream.read(CHUNK)
         except IOError as e:
             if not appclosed:
                 error_count += 1
                 messagebox.showerror("Error, ", " (%d) Error recording: %s" % (error_count, e))
         else:
             decoded_block = numpy.fromstring(block, numpy.int16)
             y = lfilter(NUMERATOR, DENOMINATOR, decoded_block)
             new_decibel = 20*numpy.log10(rms_flat(y))+int(offset.get())
             old = new_decibel
             gaugedb.set_value(float('{:.2f}'.format(new_decibel)))
             max_decibel = update_max_if_new_is_larger_than_max(new_decibel, max_decibel)
             maxdb_display.set_value(str(int(float(str(max_decibel)))))
             if new_decibel>85:
                 led.to_red(on=True)
             else:
                 led.to_red(on=False)
         root.update()
     except TclError:
         break
root.protocol('WM_DELETE_WINDOW', close)
listen()

这是一个精确的dBA表吗？我的代码工作正常，但我想检查它是否真的从麦克风反射周围的声音水平。

Answer 1

将您的代码缩进符合PEP8 8的IDE或linter；它现在是一个完美的混乱。

将全局代码移动到函数或类中。这里有两个很好的类用例-一个用于GUI，一个用于音频处理器。

offset不能是StringVar，而必须是IntVar --除其他原因外，这将消除int(offset.get())中的演员角色。不要让它没有名字，也不要让它成为孤儿；它的父对象需要成为根对象。

将bilinear导入向上移动以加入其他导入。

您的导入应该避免import *；这会使全局名称空间变得巨大，而它不需要是那样的。传统上，numpy被别名为np。

考虑编写上下文管理器以关闭音频流。

numpy.absolute(a)**2只是a**2，对吧？

删除update_max_if_new_is_larger_than_max。这只是对内置max()的一个调用。

而不是

         if new_decibel>85:
             led.to_red(on=True)
         else:
             led.to_red(on=False)

只需将布尔表达式移动到单个调用的参数并删除if。

添加PEP484类型提示。

将A_weighting中的列表转换为不可变的元组。

听一听告诉您的警告:您对np.fromstring的使用需要替换为np.frombuffer。

str(int(float(str(max_decibel))))只是..。雄伟的。使用格式字符串代替。

正如@Seb评论，44300几乎可以肯定是44100。

polymul是已弃用。使用Polynomial代替。

与rms_flat相当的是更集成的，而且可能更快

np.linalg.norm(a) / np.sqrt(len(a))

它基于这个linalg来源，进一步简化为一个自点积：

np.sqrt(a.dot(a) / len(a))

建议

import tkinter as tk
import numpy as np
import pyaudio
import tk_tools
from numpy.polynomial import Polynomial
from scipy.signal import bilinear, lfilter

CHUNKS = [4096, 9600]
CHUNK = CHUNKS[1]
FORMAT = pyaudio.paInt16
CHANNEL = 1
RATES = [44100, 48000]
RATE = RATES[1]


def A_weighting(fs: float) -> tuple[np.ndarray, np.ndarray]:
    f1 = 20.598997
    f2 = 107.65265
    f3 = 737.86223
    f4 = 12194.217
    a1000 = 1.9997

    nums = Polynomial(((2*np.pi * f4)**2 * 10**(a1000 / 20), 0,0,0,0))
    dens = (
        Polynomial((1, 4*np.pi * f4, (2*np.pi * f4)**2)) *
        Polynomial((1, 4*np.pi * f1, (2*np.pi * f1)**2)) *
        Polynomial((1, 2*np.pi * f3)) *
        Polynomial((1, 2*np.pi * f2))
    )
    return bilinear(nums.coef, dens.coef, fs)


def rms_flat(a: np.ndarray) -> float:
    return np.sqrt(a.dot(a) / len(a))


class Meter:
    def __init__(self) -> None:
        self.pa = pyaudio.PyAudio()
        self.stream = self.pa.open(
            format=FORMAT,
            channels=CHANNEL,
            rate=RATE,
            input=True,
            frames_per_buffer=CHUNK,
        )
        self.numerator, self.denominator = A_weighting(RATE)
        self.max_decibel = 0

    def __enter__(self) -> 'Meter':
        return self

    def __exit__(self, exc_type, exc_val, exc_tb) -> None:
        self.stream.stop_stream()
        self.stream.close()
        self.pa.terminate()

    def listen(self, offset: int) -> float:
        block = self.stream.read(CHUNK)
        decoded_block = np.frombuffer(block, dtype=np.int16)
        y = lfilter(self.numerator, self.denominator, decoded_block)
        new_decibel = 20*np.log10(rms_flat(y)) + offset
        self.max_decibel = max(self.max_decibel, new_decibel)
        return new_decibel


class GUI:
    def __init__(self, meter: Meter) -> None:
        self.meter = meter

        self.root = root = tk.Tk()
        root.title('Decibel Meter')
        root.grid()
        root.protocol('WM_DELETE_WINDOW', self.close)
        self.app_closed = False

        self.gaugedb = tk_tools.RotaryScale(root, max_value=120, unit=' dBA')
        self.gaugedb.grid(column=1, row=1)

        self.led = tk_tools.Led(root, size=50)
        self.led.grid(column=3, row=1)
        self.led.to_red(on=False)

        tk.Label(root, text='Too Loud').grid(column=3, row=0)
        tk.Label(root, text='Max').grid(column=2, row=0)
        tk.Label(root, text='Calibration (dB)').grid(column=4, row=0)

        self.maxdb_display = tk_tools.SevenSegmentDigits(root, digits=3, digit_color='#00ff00', background='black')
        self.maxdb_display.grid(column=2, row=1)

        self.offset = tk.IntVar(root, value=0, name='offset')
        spinbox = tk.Spinbox(root, from_=-20, to=20, textvariable=self.offset, state='readonly')
        spinbox.grid(column=4, row=1)

    def close(self) -> None:
        self.app_closed = True

    def run(self) -> None:
        while not self.app_closed:
            new_decibel = self.meter.listen(self.offset.get())
            self.update(new_decibel, self.meter.max_decibel)
            self.root.update()

    def update(self, new_decibel: float, max_decibel: float) -> None:
        self.gaugedb.set_value(np.around(new_decibel, 1))
        self.maxdb_display.set_value(f'{max_decibel:.1f}')
        self.led.to_red(on=new_decibel > 85)


def main() -> None:
    with Meter() as meter:
        gui = GUI(meter)
        gui.run()


if __name__ == '__main__':
    main()

输出

布局

你的布局需要一点爱。既然量规文本在底部，为什么不把所有标签放在底部呢？增加一些填充，以便于阅读，并增加一些调整大小的理智。不幸的是，除了缺少变量支持之外，tk_tools小部件似乎有错误的布局行为，因为它们忽略了sticky调整大小的请求；但是哦，好吧：

import tkinter as tk
import numpy as np
import pyaudio
import tk_tools
from numpy.polynomial import Polynomial
from scipy.signal import bilinear, lfilter

CHUNKS = [4096, 9600]
CHUNK = CHUNKS[1]
FORMAT = pyaudio.paInt16
CHANNEL = 1
RATES = [44100, 48000]
RATE = RATES[1]


def A_weighting(fs: float) -> tuple[np.ndarray, np.ndarray]:
    f1 = 20.598997
    f2 = 107.65265
    f3 = 737.86223
    f4 = 12194.217
    a1000 = 1.9997

    nums = Polynomial(((2*np.pi * f4)**2 * 10**(a1000 / 20), 0,0,0,0))
    dens = (
        Polynomial((1, 4*np.pi * f4, (2*np.pi * f4)**2)) *
        Polynomial((1, 4*np.pi * f1, (2*np.pi * f1)**2)) *
        Polynomial((1, 2*np.pi * f3)) *
        Polynomial((1, 2*np.pi * f2))
    )
    return bilinear(nums.coef, dens.coef, fs)


def rms_flat(a: np.ndarray) -> float:
    return np.sqrt(a.dot(a) / len(a))


class Meter:
    def __init__(self) -> None:
        self.pa = pyaudio.PyAudio()
        self.stream = self.pa.open(
            format=FORMAT,
            channels=CHANNEL,
            rate=RATE,
            input=True,
            frames_per_buffer=CHUNK,
        )
        self.numerator, self.denominator = A_weighting(RATE)
        self.max_decibel = 0

    def __enter__(self) -> 'Meter':
        return self

    def __exit__(self, exc_type, exc_val, exc_tb) -> None:
        self.stream.stop_stream()
        self.stream.close()
        self.pa.terminate()

    def listen(self, offset: int) -> float:
        block = self.stream.read(CHUNK)
        decoded_block = np.frombuffer(block, dtype=np.int16)
        y = lfilter(self.numerator, self.denominator, decoded_block)
        new_decibel = 20*np.log10(rms_flat(y)) + offset
        self.max_decibel = max(self.max_decibel, new_decibel)
        return new_decibel


class GUI:
    def __init__(self, meter: Meter) -> None:
        self.meter = meter

        self.root = root = tk.Tk()
        root.title('Decibel Meter')
        root.grid()
        root.grid_rowconfigure(index=0, weight=1)
        root.grid_rowconfigure(index=1, weight=1)
        root.grid_columnconfigure(index=0, weight=1)
        root.grid_columnconfigure(index=3, weight=1)
        root.protocol('WM_DELETE_WINDOW', self.close)
        self.app_closed = False

        self.gaugedb = tk_tools.RotaryScale(root, max_value=120, unit=' dBA')
        # This control does not respect resizing via tk.NSEW.
        self.gaugedb.grid(row=0, column=0, rowspan=2, sticky=tk.E)

        self.maxdb_display = tk_tools.SevenSegmentDigits(root, digits=3, digit_color='#00ff00', background='black')
        self.maxdb_display.grid(row=0, column=1, sticky=tk.S, padx=5)
        tk.Label(root, text='Max').grid(row=1, column=1, sticky=tk.N, padx=5)

        self.led = tk_tools.Led(root, size=50)
        self.led.to_red(on=False)
        self.led.grid(row=0, column=2, sticky=tk.S, padx=5)
        tk.Label(root, text='Too Loud').grid(row=1, column=2, sticky=tk.N, padx=5)

        self.offset = tk.IntVar(root, value=0, name='offset')
        spinbox = tk.Spinbox(root, from_=-20, to=20, textvariable=self.offset, state='readonly', width=12)
        spinbox.grid(row=0, column=3, sticky=tk.SW, padx=5)
        tk.Label(root, text='Calibration (dB)').grid(row=1, column=3, sticky=tk.NW, padx=5)

    def close(self) -> None:
        self.app_closed = True

    def run(self) -> None:
        while not self.app_closed:
            new_decibel = self.meter.listen(self.offset.get())
            self.update(new_decibel, self.meter.max_decibel)
            self.root.update()

    def update(self, new_decibel: float, max_decibel: float) -> None:
        self.gaugedb.set_value(np.around(new_decibel, 1))
        self.maxdb_display.set_value(f'{max_decibel:.1f}')
        self.led.to_red(on=new_decibel > 85)


def main() -> None:
    with Meter() as meter:
        gui = GUI(meter)
        gui.run()


if __name__ == '__main__':
    main()