1. A New Texture Descriptor: Composite Sub_band Gradient Vector 2006.3.30

2. Texture Analysis by Gradient-Based Feature  Gradient operator (Sobel) reflect the magnitude and direction.  Summing up the magnitude in the same direction.  Every successive k(=10) directions grouped together

3.  Euclidean distance: measure the difference between two gradient vector.

5. Composite Subband Gradient Vector  drawback

6.  LL sub-image: Both horizontal and vertical direction have low- frequencies.  LH sub-image: Horizontal direction has low-frequencies and vertical direction has high-frequencies

7.  HL sub-image: Horizontal direction has high- frequencies and vertical direction has low-frequencies.  HH sub-image: Both horizontal and vertical direction have high- frequencies.

8.  SGV1 be the sub-image LL  SGV2 be the sub-image LH  SGV3 be the sub-image HL  SGV4 be the sub-image HH  CSGV = SGV1|| SGV2|| SGV3|| SGV4(where || is append operator)  CSGV is called Composite Subband Gradient Vector

9. (g)=>( h) (g)=>(i) Dis t. 5.509916.605 7

10. Segmentation using Reduced-Length CSG Vectors  Segmentation process into three stages: (1).split stage. (2).merge stage. (3).boundary stage.  Assume that an image I is of size m*m pixels

11. Split stage.

13. Merge stage.

15. Boundary stage.

17. Result(Split:0.1 Merge:0.7)