Dynamic chain-based thresholding using global characteristics
View Patent ↗One embodiment relates to an apparatus for image processing. The apparatus includes a candidate edge chain identifier for identifying candidate edge chains in an image being processed, means for calculating a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed, and a threshold applicator for applying the dynamic chain-based threshold function to the candidate edge chains. The characteristic of the image being processed may be global in that it is determined from the overall image being processed. A system may include an encoder or a decoder, both of which include the above apparatus. Another embodiment relates to a method for image processing. The method determines a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed and applies the dynamic threshold to a candidate edge chain.
1. A method for image processing, the method comprising:
applying a point-based threshold function to identify candidate edge chains in an image being processed;
determining a dynamic chain-based threshold function that is dependent on a global characteristic of the image being processed;
applying the dynamic chain-based threshold function to selectively filter the candidate edge chains; and
removing from a set of edge chains those candidate edge chains that fail to pass the dynamic chain-based threshold function,
wherein the global characteristic comprises a global measure of color variation that is calculated over an image.
2. The method of claim 1 , wherein the global measure comprises a mean measure of the color variation.
3. The method of 1 , wherein the global measure comprises a median measure of the color variation.
4. The method of claim 1 , wherein the global measure is calculated over the candidate edge chains within the image.
5. The method of claim 1 , wherein the dynamic chain-based threshold function comprises a linear function of the global characteristic.
6. An apparatus for image processing, the apparatus comprising:
a candidate edge chain identifier for identifying candidate edge chains in an image being processed;
means for determining a dynamic chain-based threshold function that is dependent on a global characteristic of the image being processed; and
a threshold applicator for applying the dynamic chain-based threshold function to selectively filter the candidate edge chains,
wherein the global characteristic comprises a global measure of color variation that is calculated over an image.
7. The apparatus of 6 , wherein the global measure comprises a mean measure of the color variation.
8. The apparatus of 6 , wherein the global measure comprises a median measure of the color variation.
9. The apparatus of 6 , wherein the global measure is calculated over the candidate edge chains within the image.
10. The apparatus of 6 , wherein the dynamic chain-based threshold function comprises a linear function of the global characteristic.
11. The apparatus of claim 6 , wherein the apparatus comprises a video encoder.
12. The apparatus of claim 11 , wherein the video encoder is configured to operate cooperatively with a video decoder, and wherein the video decoder also comprises the edge identifier, the means for determining, and the thresholder.
13. The apparatus of claim 6 , wherein the apparatus comprises a video decoder.
14. A method for processing an image, the method comprises:
determining a dynamic chain-based threshold function that is dependent on a global measure of color variation of the image being processed; and
applying the dynamic chain-based threshold function to a candidate edge chain.
15. A system for image processing, the system comprising:
an encoder that includes a candidate edge chain identifier for identifying candidate edge chains in an image being processed, means for calculating a dynamic chain-based threshold function that is dependent on global measure of color variation of the image being processed, and a threshold applicator for applying the dynamic chain-based threshold function to the candidate edge chains; and
a decoder configured to operate in cooperation with the encoder, wherein the decoder also includes the candidate edge chain identifier, the means for calculating, and the threshold applicator.