# inverse discrete cosine transform (IDCT)

The DCT transformation (Discrete Cosine Transform) is used in image compression when pixel graphics are converted to JPEG

. When converting JPEG to pixel graphics, on the other hand, the IDCT transformation (Inverse Discrete Cosine Transform) is used. It takes over the inverse part of the DCT transformation and, after de-quantizing the quantized coefficient matrix, converts its values into the brightness and color signals using DCT basis functions, from which the RGB signals of the pixel graphics are then obtained.