Systems and methods for processing pre-multiplied alpha content
This disclosure is directed toward systems and methods of pre-multiplied alpha handling during image processing operations. The image processing circuitry may include hardware that enables removal and insertion of pre-multiplied alpha content into red, green, blue (RGB) pixel values during gamma and scaling operations. The division by alpha and multiplication by alpha hardware may enable removal of pre-multiplied alpha content to RGB pixel values prior to gamma operations and insertion of pre-multiplied alpha content into RGB pixel values prior to scaling operations.
1. An electronic device comprising:
an electronic display configured to display an image based at least in part on processed image data; and
image processing circuitry configured to:
receive a plurality of sub-pixel values comprising red, green, blue (RGB) pixel values that are pre-multiplied by an alpha pixel value;
divide each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply a fixed de-gamma function to each of the RGB pixel values with the pre-multiplied alpha pixel value removed.
2. The electronic device of claim 1 , wherein the image processing circuitry is configured to:
multiply each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value; and
perform scaling operations on each of the RGB pixel values that are pre-multiplied by the alpha pixel value.
3. The electronic device of claim 2 , wherein an output of the multiplication of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value is quantized to a precision of the RGB pixel values.
4. The electronic device of claim 2 , wherein the image processing circuitry is configured to:
divide each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply a fixed re-gamma function to each of the RGB pixel values with the pre-multiplied alpha pixel value removed.
5. The electronic device of claim 1 , wherein dividing each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value comprises using a look-up-table (LUT) to multiply the RGB pixel values by a reciprocal alpha value.
6. The electronic device of claim 5 , wherein the LUT comprises equally-spaced entries corresponding to an alpha bit value of the alpha pixel value.
7. An electronic device comprising:
an electronic display configured to display an image based at least in part on processed image data; and
image processing circuitry configured to:
receive a plurality of sub-pixel values comprising pixel values that include are pre-multiplied by an alpha pixel value;
divide each of the pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply one or more image processing operations to each of the pixel values of the plurality of sub-pixel values with the pre-multiplied alpha pixel value removed.
8. The electronic device of claim 7 , wherein dividing each pixel value of the plurality of sub-pixel values comprises performing a bit shifting operation on each pixel value of the plurality of sub-pixel values that include the pre-multiplied alpha value.
9. The electronic device of claim 7 , wherein the one or more image processing operations comprise fixed de-gamma operations.
10. The electronic device of claim 7 , wherein dividing each pixel value of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value comprises using a look-up-table (LUT) to multiply each pixel value of the plurality of sub-pixel values by a reciprocal alpha value.
11. The electronic device of claim 7 , wherein an output of the multiplication of each pixel value of the plurality of sub-pixel values by the alpha pixel value is quantized to a precision of the plurality of sub-pixel values.
12. The electronic device of claim 11 , wherein the image processing circuitry is configured to:
divide each of the pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply a fixed re-gamma function to each of the pixel values of the plurality of sub-pixel values with the pre-multiplied alpha pixel value removed.
13. The electronic device of claim 7 , wherein the plurality of sub-pixel values comprise RGB pixel values, YCC pixel values, CMY pixel values, or any combination thereof.
14. An electronic device comprising:
an electronic display configured to display an image based at least in part on processed image data; and
memory-to-memory scaler and rotator (MSR) circuitry configured to:
receive a plurality of sub-pixel values comprising red, green, blue (RGB) pixel values that include a pre-multiplied alpha pixel value;
divide each of the RGB pixel values of the plurality of sub-pixel values by an alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply a fixed de-gamma function to each of the RGB pixel values with the pre-multiplied alpha pixel value removed.
15. The electronic device of claim 14 , wherein the MSR circuitry is configured to:
multiply each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value; and
perform scaling operations on each of the RGB pixel values that include the pre-multiplied alpha pixel value.
16. The electronic device of claim 15 , wherein an output of the multiplication of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value is quantized to a precision of the RGB pixel values.
17. The electronic device of claim 14 , wherein dividing each of the pixel values
comprises performing a bit shifting operation on the plurality of sub-pixel values that include the pre-multiplied alpha pixel value.
18. The electronic device of claim 14 , wherein dividing each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value comprises using a look-up-table (LUT) to multiply the pixel values by a reciprocal alpha value.
19. The electronic device of claim 18 , wherein the LUT comprises equally-spaced entries corresponding to the alpha pixel value.
20. The electronic device of claim 14 , wherein the MSR circuitry is configured to:
divide each of the RGB pixel values of the plurality of sub-pixel values by the alpha pixel value to remove the pre-multiplied alpha pixel value; and
apply a fixed re-gamma function to each of the RGB pixel values with the pre-multiplied alpha pixel value removed.