Method and apparatus for scaling image block

An image scaling device for calculating a pixel value of a target pixel within a scaled image block scaled from an image block, the image scaling device comprising:

• a selecting device for selecting a plurality of reference pixels from the image block, wherein each reference pixel has a pixel value and corresponds to a transparency parameter, and the reference pixel with a transparency parameter less than or equal to a predetermined value is defined as a background pixel and the reference pixel with a transparency parameter greater than the predetermined value is defined as a foreground pixel;
• a weight value setting unit coupled to the selecting device for respectively setting a corresponding weight value for each reference pixel and for adjusting the weight values of the reference pixels according to a combination of the transparency parameters of the reference pixels which is recorded in a look-up table, wherein the look-up table stores all combinations of the transparency parameters of the reference pixels and stores the adjusted weight values of the reference pixels corresponding to each combination of the transparency parameters;
• a storage unit coupled to the weight value setting unit for storing the look-up table;
• and
• a computing device coupled to the selecting device and the weight value setting unit for generating the pixel values of the reference pixels to generate the pixel value of the target pixel according to the adjusted weight values of the reference pixels.

An image scaling method for calculating a pixel value of a target pixel within a scaled image block scaled from an image block, the method comprising:

• selecting a plurality of reference pixels from the image block, wherein each reference pixel has a pixel value and corresponds to a transparency parameter;
• respectively setting a corresponding weight value for each reference pixel according to the transparency parameter of the reference pixel and a look-up table, wherein the look-up table stores an adjusted weight value corresponding to each transparency parameter, and the step of setting the weight values comprises:
• respectively setting a non-adjusted weight value for each reference pixel;
• and
• adjusting the non-adjusted weight values to produce adjusted weight values according to the look-up table and then utilizing the adjusted weight values as the weight values of the reference pixels;
• and
• generating the pixel values of the reference pixels to generate the pixel value of the target pixel according to the weight values of the reference pixels;
• wherein the reference pixel with a transparency parameter less than or equal to a predetermined value is defined as a background pixel and the reference pixel with a transparency parameter greater than the predetermined value is defined as a foreground pixel.

An image scaling device for calculating a pixel value of a target pixel within a scaled image block, scaled from and image block the image scaling device comprising:

• a selecting device for selecting a plurality of reference pixels from the image block, wherein each reference pixel has a pixel value and corresponds to a transparency parameter;
• a weight value setting unit coupled to the selecting device for respectively setting a corresponding weight value for each reference pixel according to the transparency parameter of the reference pixel and a look-up table, wherein the look-up table stores an adjusted weight value corresponding to each transparency parameter, the weight value setting unit respectively sets a non-adjusted weight value for each reference pixel and then adjusts the non-adjusted weight values to produce adjusted weight values according to the transparency parameters of the reference pixels according to the look-up table, and the adjusted weight values are employed to be the weight values of the reference pixels;
• a storage unit coupled to the weight value setting unit for storing the look-up table;
• and
• a computing device coupled to the weight value setting unit for generating the pixel values of the reference pixels to generate the pixel value of the target pixel according to the weight values of the reference pixels;
• wherein the reference pixel with a transparency parameter less than or equal to a predetermined value is defined as a background pixel and a reference pixel with a transparency parameter greater than the predetermined value is defined as a foreground pixel.