Method and apparatus for synchronizing an analog video signal to an LCD monitor

1. A method of determining a synchronizing horizontal resolution (Htotal) comprising:

determining a transition zone for each of a plurality of features for each value of a range of Htotal;

determining a narrowest transition zone, and

associating a particular one of the range of Htotal corresponding to the narrowest transition zone to the synchronizing horizontal resolution.

2. A method as recited in claim 1 , further comprising:

determining a synchronizing phase based upon the synchronizing horizontal resolution for an estimated phase,

determining a flat region of a video signal corresponding to a selected found feature; and

selecting the synchronizing phase based upon the flat region.

3. A method as recited in claim 2 , further comprising:

finding the plurality of features for a selected one value of the range of Htotal.

4. A method as recited in claim 3 , wherein the finding the plurality of features comprises:

initializing a step value, a region value, and a previous pixel value to a corresponding initial value;

grabbing a pixel value at a location corresponding to the step value plus the region value;

setting a current pixel value as the grabbed pixel value; and

subtracting the current pixel value from the previous pixel value to form a pixel value difference.

5. A method as recited in claim 4 , wherein the finding the plurality of features further comprises:

determining if the pixel value difference indicates a found feature;

storing a set of pixel coordinates as a feature based upon the location;

marking the region as a used region;

incrementing a feature count; and

determining if the feature count is greater than or equal to a pre-selected feature count.

6. A method as recited in claim 5 , wherein the determining the transition zone comprises:

initializing a phase, a feature value, and a feature change value to a corresponding initial value;

selecting one of the plurality of found features;

grabbing a pixel from the selected feature;

determining if the selected feature moved;

if the selected feature moved, then incrementing the feature change value; and

if the feature change value is equal to 1, then storing the phase as a transition start value.

7. A method as recited in claim 6 , wherein the measuring the transition zone further comprises:

if the feature change in not equal to 1 , then determining if the feature change value is equal to the feature value;

if the feature change value is equal to the feature value, then storing the phase as a transition end value; and

subtracting the transition start value from the transition end value.

8. A computer readable medium having an encoded computer program for determining a synchronizing horizontal resolution (Htotal) comprising:

computer code for measuring a transition zone for each of a plurality of features for each value of a range of Htotal;

computer code for determining a narrowest transition zone,

computer code for associating a particular one of the range of Htotal; and corresponding to the narrowest transition zone to the synchronizing horizontal resolution.

9. The computer readable medium encoded with a computer program as recited in claim 8 , further comprising:

computer code for determining a synchronizing phase based upon the synchronizing horizontal resolution;

computer code for estimating a phase;

computer code for determining a flat region of a video signal corresponding to a selected found feature; and

computer code for selecting the synchronizing phase based upon the flat region.

10. The computer readable medium encoded with a computer program as recited in claim 9 , further comprising:

computer code for finding the plurality of features for a selected one value of the range of Htotal.

11. The computer readable medium encoded with a computer program as recited in claim 10 , wherein the finding the plurality of features comprises:

computer code for initializing a step value, a region value, and a previous pixel value to a corresponding initial value;

computer code for grabbing a pixel value at a location corresponding to the step value plus the region value;

computer code for setting a current pixel value as the grabbed pixel value; and

computer code for subtracting the current pixel value from the previous pixel value to form a pixel value difference.

12. The computer readable medium encoded with a computer program as recited in claim 11 , wherein the finding the plurality of features further comprises:

computer code for determining if the pixel value difference indicates a found feature;

computer code for storing a set of pixel coordinates as a feature based upon the location;

computer code for marking the region as a used region;

computer code for incrementing a feature count; and

computer code for determining if the feature count is greater than or equal to a pre-selected feature count.

13. The computer readable medium encoded with a computer program as recited in claim 12 , wherein the measuring a transition zone comprises:

computer code for initializing a phase, a feature value, and a feature change value to a corresponding initial value;

computer code for selecting one of the plurality of found features;

computer code for grabbing a pixel from the selected feature;

computer code for determining if the selected feature moved;

if the selected feature moved, then incrementing the feature change value; and

computer code for storing the phase as a transition start value if the feature change value is equal to 1.

14. The computer readable medium encoded with a computer program as recited in claim 13 , wherein the measuring the transition zone further comprises:

computer code for determining if the feature change value is equal to the feature value if the feature change in not equal to 1;

computer code for storing the phase as a transition end value if the feature change value is equal to the feature value; and

computer code for subtracting the transition start value from the transition end value.