我需要一段完整的基于lzw编码实现图像压缩设计与实现的代码

以下是一个基于LZW编码实现图像压缩的Python代码示例：

import numpy as np
from PIL import Image

def compress(image_path, output_path):
    # Load image as numpy array
    image = np.array(Image.open(image_path))

    # Flatten image into a 1D array
    pixels = image.flatten()

    # Create dictionary with all possible pixel values
    dictionary = {i: chr(i) for i in range(256)}

    # Initialize variables
    string = ""
    compressed = []

    # LZW compression algorithm
    for pixel in pixels:
        string_plus_pixel = string + chr(pixel)
        if string_plus_pixel in dictionary:
            string = string_plus_pixel
        else:
            compressed.append(dictionary[string])
            dictionary[string_plus_pixel] = len(dictionary)
            string = chr(pixel)

    # Add last string to compressed output
    if string in dictionary:
        compressed.append(dictionary[string])

    # Save compressed output to file
    with open(output_path, "wb") as f:
        for code in compressed:
            f.write(bytes([code]))

def decompress(input_path, output_path):
    # Load compressed file as bytes
    with open(input_path, "rb") as f:
        compressed = f.read()

    # Create dictionary with all possible pixel values
    dictionary = {i: chr(i) for i in range(256)}

    # Initialize variables
    string = ""
    decompressed = []

    # LZW decompression algorithm
    for code in compressed:
        code = int(code)
        if code in dictionary:
            entry = dictionary[code]
        elif code == len(dictionary):
            entry = string + string[0]
        else:
            raise ValueError("Bad compressed code: %d" % code)

        decompressed.append(ord(entry[0]))

        if string:
            dictionary[len(dictionary)] = string + entry[0]

        string = entry

    # Convert 1D array back into image
    width, height = np.array(Image.open(input_path)).size
    pixels = np.array(decompressed).reshape(height, width).astype(np.uint8)
    Image.fromarray(pixels).save(output_path)

# Example usage
compress("input.png", "compressed.lzw")
decompress("compressed.lzw", "output.png")

这段代码将输入的图像文件进行LZW压缩，并将压缩后的结果保存到文件中。然后可以使用相同的代码对压缩文件进行解压缩，得到原始图像文件。请注意，这个实现并不是最优化的，可能会存在一些性能问题。