Performance Analysis of Three Likelihood Measures for Color Image Processing Arash AbadpourDr. Shohreh Kasaei Mathematics Science DepartmentComputer Engineering Department Sharif University of Technology, Tehran, Iran
Outline Introduction Image Segmentation, Color Image Segmentation, Fuzzy Membership, What we have done. Method Likelihood Measure, Homogeneity Criteria, Fuzzy Membership, PCA Everywhere, Different Color spaces. Experimental Results Fuzzyfication, Noise Robustness, Parameter Sensitivity, Homogeneity Criteria. Conclusions.
Image Segmentation A Low Level Operation, before Recognition, Compression, Tracking,… Splitting to Homogenous Regions. An Spatial-Spectral Process: Satisfying (sometimes) Contradictory Concerns. Based on A Likelihood Measure or A Homogeneity Criteria.
Color Image Segmentation The Easy Way: A Color image is a Combination of Grayscale Images. Using a Min/Max method. The Better way: Euclidean: Only depends on the central point. Generally used in the literature. Known as an applicable measure. Mahalonobis: Depending on the central point and the distribution margins. Called Weighted Euclidean, when used in color domain. Computationally expensive.
Fuzzy Membership Likelihood Measure: Rank Better Members with Smaller Numbers. Mapping is needed: Gaussian is used Generally.
What have we done? Comparing the Euclidean, Mahalonobis and Reconstruction Error, in terms of: Image Fuzzyfication (Likelihood Measures). Homogeneity Decision.
Likelihood Measures Distances Euclidean. Mahalonobis. Reconstruction Error. Normalization.
Homogeneity Criteria
Fuzzy Membership Mapping, Flat Ceil. Manipulated Butterworth.
PCA Everywhere Although not mentioned, Euclidean and Mahalanobis are PCA-Based. Euclidean: Mahalonibus:clear. Reconstruction Error (RE):
Color Spaces Although RGB Used, the Same hold for Linear Reversible color spaces: CMYK, YCbCr, YIQ, YUV, I1I2I3 Not for: Nonlinear: HIS, HSV, CIE-XYZ, CIELab, CIE-Luv, CIE-LHC, HMMD. Irreversible.
Experimental Results Matlab 6.5, Image Processing Toolbox. 42 Samples Images: RGB. Low-compressed, JPEG.
Fuzzy Membership.
Computational Complexity & Memory Computational Complexity: Data Extraction: Euclidean: Mean. Mahalonobis: Mean and Complete Al PCs. RE: Mean and one PC. Measurement: Euclidean: 7 flops. Mahalonobis 111 flops. RE: 22 flops. Memory: Euclidean: 3. Mahalonobis: 12. RE: 6.
Fuzzyfication
Noise Robustness
Parameter Sensitivity Different values of p.
Homogeneity Criteria
Conclusions Analyzing the performance of: Euclidean, Mahalanobis, and Reconstruction Error. As likelihood measures and homogeneity criteria. Euclidean distance: Used commonly, is the fastest and needs least memory. Neither gives applicable fuzzyfication results, nor gives proper homogeneity criteria. Comparing Reconstruction error and Mahalonobis: RE is more robust against noise, leads to promising homogeneity criteria, is fastest and needs less memory.
Any Questions?