Base64 Process

This module uses pybase64 internally and provides both bytes and str interfaces (e.g. img_to_b64 vs img_to_b64str).

• Common issue: string vs bytes?

  In Python, str is a sequence of Unicode characters, while bytes is a sequence of raw bytes. Base64 operates on bytes, so encoding/decoding typically happens on bytes. String variants are provided for convenience.

img_to_b64

img_to_b64(img: np.ndarray, imgtyp: str | int | IMGTYP = IMGTYP.JPEG, **kwargs: object) -> bytes | None

• Description: Encodes a numpy image into Base64 bytes.

• Parameters

  • img (np.ndarray): Image array.
  • imgtyp (str | int | IMGTYP): Image type. Supports IMGTYP.JPEG / IMGTYP.PNG. Default is IMGTYP.JPEG.

• Returns

  • bytes | None: Base64 bytes; returns None when encoding fails.

• Notes

  • For backward compatibility, IMGTYP=... is also accepted (providing both imgtyp and IMGTYP raises TypeError).

• Example

  from capybara.vision.improc import IMGTYP, img_to_b64, imread
  
  img = imread('lena.png')
  b64 = img_to_b64(img, imgtyp=IMGTYP.PNG)

npy_to_b64

npy_to_b64(x: np.ndarray, dtype='float32') -> bytes

• Description: Encodes a numpy array into Base64 bytes.

• Parameters

  • x (np.ndarray): Numpy array.
  • dtype (str): Cast dtype before encoding. Default is 'float32'.

• Returns

  • bytes: Base64 bytes.

• Example

  import numpy as np
  from capybara.vision.improc import npy_to_b64
  
  x = np.random.rand(100, 100, 3)
  b64 = npy_to_b64(x)

npy_to_b64str

npy_to_b64str(x: np.ndarray, dtype='float32', string_encode: str = 'utf-8') -> str

• Description: Encodes a numpy array into a Base64 string.

• Parameters

  • x (np.ndarray): Numpy array.
  • dtype (str): Cast dtype before encoding. Default is 'float32'.
  • string_encode (str): String encoding. Default is 'utf-8'.

• Returns

  • str: Base64 string.

• Example

  import numpy as np
  from capybara.vision.improc import npy_to_b64str
  
  x = np.random.rand(100, 100, 3)
  b64str = npy_to_b64str(x)

img_to_b64str

img_to_b64str(img: np.ndarray, imgtyp: str | int | IMGTYP = IMGTYP.JPEG, string_encode: str = 'utf-8', **kwargs: object) -> str | None

• Description: Encodes a numpy image into a Base64 string.

• Parameters

  • img (np.ndarray): Image array.
  • imgtyp (str | int | IMGTYP): Image type. Supports IMGTYP.JPEG / IMGTYP.PNG. Default is IMGTYP.JPEG.
  • string_encode (str): String encoding. Default is 'utf-8'.

• Returns

  • str | None: Base64 string; returns None when encoding fails.

• Notes

  • For backward compatibility, IMGTYP=... is also accepted (providing both imgtyp and IMGTYP raises TypeError).

• Example

  import capybara as cb
  
  img = cb.imread('lena.png')
  b64str = cb.img_to_b64str(img, imgtyp=cb.IMGTYP.PNG)

b64_to_img

b64_to_img(b64: bytes) -> np.ndarray | None

• Description: Decodes Base64 bytes into a numpy image.

• Parameters

  • b64 (bytes): Base64 bytes.

• Returns

  • np.ndarray | None: Decoded image; returns None on failure.

• Example

  from capybara.vision.improc import b64_to_img, img_to_b64, imread
  
  b64 = img_to_b64(imread('lena.png'))
  img = b64_to_img(b64)

b64str_to_img

b64str_to_img(b64str: str | None, string_encode: str = 'utf-8') -> np.ndarray | None

• Description: Decodes a Base64 string into a numpy image.

• Parameters

  • b64str (str | None): Base64 string.
  • string_encode (str): String encoding. Default is 'utf-8'.

• Returns

  • np.ndarray | None: Decoded image; returns None on failure.

• Example

  from capybara.vision.improc import b64str_to_img, img_to_b64, imread
  
  b64 = img_to_b64(imread('lena.png'))
  b64str = b64.decode('utf-8')
  img = b64str_to_img(b64str)

b64_to_npy

b64_to_npy(x: bytes, dtype='float32') -> np.ndarray

• Description: Decodes Base64 bytes into a numpy array.

• Parameters

  • x (bytes): Base64 bytes.
  • dtype (str): Output dtype. Default is 'float32'.

• Returns

  • np.ndarray: Decoded numpy array.

• Example

  import numpy as np
  from capybara.vision.improc import b64_to_npy, npy_to_b64
  
  b64 = npy_to_b64(np.random.rand(100, 100, 3))
  x = b64_to_npy(b64)

b64str_to_npy

b64str_to_npy(x: str, dtype='float32', string_encode: str = 'utf-8') -> np.ndarray

• Description: Decodes a Base64 string into a numpy array.

• Parameters

  • x (str): Base64 string.
  • dtype (str): Output dtype. Default is 'float32'.
  • string_encode (str): String encoding. Default is 'utf-8'.

• Returns

  • np.ndarray: Decoded numpy array.

• Example

  import numpy as np
  from capybara.vision.improc import b64str_to_npy, npy_to_b64
  
  b64 = npy_to_b64(np.random.rand(100, 100, 3))
  x = b64str_to_npy(b64.decode('utf-8'))