1. A computer program product, tangibly stored on a computer-readable medium, for compositing digital graphics objects, comprising instructions operable to cause a programmable processor to perform operations including:
compositing a transparency group of digital graphics objects on a non-transparent group backdrop to generate an accumulated result, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group, wherein removal of a color contribution of the group backdrop effects a reversal of compositing the group backdrop with a normal blend mode.
2. The computer program product of claim 1, where the accumulated result includes an accumulated color Cn and removing the contribution from the group backdrop effecting a reversal of compositing the group backdrop with the normal blend mode includes removing a backdrop color Co of the group backdrop from the accumulated color based on the expression Cn \u2212(bf)(Co), where bf is a backdrop fraction characterizing a relative contribution of the backdrop color to the accumulated color.
3. The computer program product of claim 1, where compositing the transparency group of digital graphics objects includes instructions operable to cause the programmable processor to perform operations including compositing a sequence of digital graphics objects in the transparency group, the sequence including a last object in the sequence, to generate the accumulated result for each object in the sequence; and
removing the contribution of the group backdrop from the accumulated result includes instructions operable to remove the color contribution from the accumulated result after compositing the last digital graphics object in the sequence.
4. The computer program product of claim 1, the instructions further operable to cause a programmable processor to perform operations including:
compositing the compositing result for the transparency group on the group backdrop using the normal blend mode to generated an overall composited object; and
rendering the overall composited object.
5. A system for compositing digital graphics objects comprising:
one or more computers configured to perform operations including:
compositing a transparency group of digital graphics objects on a non-transparent group backdrop to generate an accumulated result, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group, wherein removal of a color contribution of the group backdrop effects a reversal of compositing the group backdrop with a normal blend mode.
6. The system of claim 5, where the accumulated result includes an accumulated color Cn and removing the contribution from the group backdrop effecting a reversal of compositing the group backdrop with the normal blend mode includes removing a backdrop color Co of the group backdrop from the accumulated color based on the expression Cn \u2212(bf)(Co), where bf is a backdrop fraction characterizing a relative contribution of the backdrop color to the accumulated color.
7. The system of claim 5, where compositing the transparency group of digital graphics objects includes compositing a sequence of digital graphics objects in the transparency group, the sequence including a last object in the sequence, to generate the accumulated result for each object in the sequence; and
removing the contribution of the group backdrop from the accumulated result includes instructions operable to remove the color contribution from the accumulated result after compositing the last digital graphics object in the sequence.
8. The system of claim 5, the one or more computers further configured to perform operations including:
compositing the compositing result for the transparency group on the group backdrop using the normal blend mode to generated an overall composited object; and
rendering the overall composited object.
9. A method for compositing digital graphics objects comprising:
compositing, using one or more computing devices, a transparency group of digital graphics objects on a non-transparent group backdrop to generate an accumulated result, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group, wherein removal of a color contribution of the group backdrop effects a reversal of compositing the group backdrop with a normal blend mode.
10. The method of claim 9, where the accumulated result includes an accumulated color Cn and removing the contribution from the group backdrop effecting a reversal of compositing the group backdrop with the normal blend mode includes removing a backdrop color Co of the group backdrop from the accumulated color based on the expression Cn \u2212(bf)(Co), where bf is a backdrop fraction characterizing a relative contribution of the backdrop color to the accumulated color.
11. The method of claim 9, where compositing the transparency group of digital graphics objects includes compositing a sequence of digital graphics objects in the transparency group, the sequence including a last object in the sequence, to generate the accumulated result for each object in the sequence; and
removing the contribution of the group backdrop from the accumulated result includes instructions operable to remove the color contribution from the accumulated result after compositing the last digital graphics object in the sequence.
12. The method of claim 9, further comprising:
compositing the compositing result for the transparency group on the group backdrop using the normal blend mode to generated an overall composited object; and
rendering the overall composited object.
13. A computer program product, tangibly stored on a computer-readable medium, for compositing digital graphics objects, comprising instructions operable to cause a programmable processor to perform operations including:
receiving a stack of digital image layers for a digital image, the stack including a transparency group and a non-transparent group backdrop for the transparency group, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group;
compositing the transparency group of digital graphics objects on the group backdrop to generate an accumulated result, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group; and
compositing the digital image, wherein the instructions to composite the digital image include instructions to composite the compositing result for transparency group with the group backdrop, wherein the contribution of the group backdrop is included only once in the composited digital image.
14. A system for compositing digital graphics objects comprising:
one or more computers configured to perform operations including:
receiving a stack of digital image layers for a digital image, the stack including a transparency group and a non-transparent group backdrop for the transparency group, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group;
compositing the transparency group of digital graphics objects on the group backdrop to generate an accumulated result, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group; and
compositing the digital image, wherein the instructions to composite the digital image include instructions to composite the compositing result for transparency group with the group backdrop, wherein the contribution of the group backdrop is included only once in the composited digital image.
15. A method for compositing digital graphics objects comprising:
receiving a stack of digital image layers for a digital image, the stack including a transparency group and a non-transparent group backdrop for the transparency group, the transparency group including two or more contiguous digital graphics objects in a stack of digital graphics objects, the group backdrop being a result of compositing elements in the stack up to but not including the first element of the transparency group;
compositing, using one or more computing devices, the transparency group of digital graphics objects on the group backdrop to generate an accumulated result, the compositing of the transparency group including combining colors specified by the group backdrop and one or more digital graphics objects in the transparency group such that the accumulated result includes a contribution of the group backdrop;
removing the contribution of the group backdrop from the accumulated result to generate a compositing result for the transparency group; and
compositing the digital image, wherein the instructions to composite the digital image include instructions to composite the compositing result for transparency group with the group backdrop, wherein the contribution of the group backdrop is included only once in the composited digital image.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
I claim:
1. A band pass filter for a base station in a wireless communication system, comprising:
at least first and second band pass filters;
a selector receiving at least one signal and supplying the signal to one of the first and second band pass filters; and
a controller controlling the selector based on a frequency of the signal.
2. The band pass filter of claim 1, wherein the controller controls the selector to select the one of the first and second band pass filters having a pass band with a center frequency closest to a center frequency of the signal.
3. The band pass filter of claim 2, wherein the first and second band pass filters have a 70 MHz pass band, and the at least one signal has a frequency spectrum of no more than 15 MHz.
4. The band pass filter of claim 1, wherein
the controller includes a look up table that maps frequencies to one of the first and second band pass filters; and
the controller receives a frequency of the signal, obtains the one of the first and second band pass filters from the look up table using the received frequency, and controls the selector to supply the signal to the obtained band pass filter.
5. The band pass filter of claim 1, further comprising:
a third band pass filter; and wherein
the selector supplies the signal to one of the first, second and third band pass filters.
6. The band pass filter of claim 1, further comprising:
a summer summing output of the first and second band pass filters.
7. The band pass filter of claim 1, wherein
the selector receives three RF signals; and
the controller controls the selector based on frequencies of the three RF signals.
8. A band pass filter for a base station in a wireless communication system, comprising:
first, second and third band pass filters;
a selector receiving at least one signal and supplying the signal to one of the first, second and third band pass filters; and
a controller controlling the selector to select the one of the first, second and third band pass filters having a pass band with a center frequency closest to a center frequency of the signal.
9. The band pass filter of claim 8, wherein the controller includes a look up table that maps frequencies to one of the first, second and third band pass filters, the controller receives a frequency of the signal, obtains the one of the first, second and third band pass filters from the look up table using the received frequency, and controls the selector to supply the signal to the obtained band pass filter.
10. A method of filtering signals for transmission by a base station in a wireless communication system, comprising:
receiving at least one signal for transmission;
selecting a filter pass band based on a frequency of the received signal; and
filtering the signal using a band pass filter with the selected pass band.
11. The method of claim 10, wherein the selecting step selects a filter pass band, from a group of at least two filter pass bands, having a center frequency closest to a center frequency of the signal.
12. The method of claim 11, wherein the selectable filter pass bands have a pass band of 70 MHz, and the signal has a frequency spectrum of no more than 15 MHz.
13. The method of claim 10, wherein the selecting step comprises:
obtaining a filter pass band from a look up table using a received frequency of the signal.
14. The method of claim 1, wherein
the receiving step receives three RF signals; and
the selecting step selects the filter pass band based on frequencies of the three RF signals.