1. A. Vadivel, M. Mohan, Shamik Sural and A. K. Majumdar
SEGMENTATION USING SATURATION THRESHOLDING AND ITS APPLICATION IN CONTENT-BASED RETRIEVAL OF IMAGES
A. Vadivel, M. Mohan, Shamik Sural and
A. K. Majumdar
INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR, INDIA.

2. ANALYSIS OF THE HSV COLOR SPACE
Three dimensional representation of the HSV color space
Central vertical axis represents intensity, I
Hue, H, is an angle in the range [0,2p] relative to the red axis.
Saturation, S, is the depth or purity of color
11/11/2018
Indian Institute of Technology, Kharagpur

3. VISUAL PERCEPTION IN THE HSV COLOR SPACE
(b)
Variation of color perception with (a) saturation (Decreasing from 1 to 0 right to left) for a fixed value of intensity and (b) intensity (Decreasing from 255 to 0 right to left) for a fixed value of saturation.
11/11/2018
Indian Institute of Technology, Kharagpur

4. SATURATION THRESHOLDING
Use Saturation of a Pixel to Determine
Hue or Intensity is more pertinent to Human Visual Perception
Ignore Actual Value Saturation
Image pixels from a distribution of “colors”
“gray color” and
“true color”
Threshold to determine a “true color” and a “gray color” pixel:
thsat(V) = 1.0 – (0.8V/255)
11/11/2018
Indian Institute of Technology, Kharagpur

5. Indian Institute of Technology, Kharagpur
IMAGE REPRESENTATION
Each image is represented as a collection of pixel features I{(pos, [t|g], val)}
val [0,2p] if [t|g] takes a value of t and
val [0,255] if [t|g] takes a value of g.
Approximation occurs as shown below
(a) (b) (c) (d)
(a) Original Image (b) HSV Approximation (c) RGB approximation with all low order bits set to 0 and (d) RGB approximation with all low order bits set to 1.
11/11/2018
Indian Institute of Technology, Kharagpur

6. Indian Institute of Technology, Kharagpur
IMAGE SEGMENTATION
Pixel Grouping by K-means Clustering Algorithm
I {O1|O2|O3|….|On}
Oi([t|g], val, {pos})
Each partition represents either a “true color” value or a “gray color” value
Consists of the positions of all the image pixels that have colors close to val.
Post Processing
Connected Component Analysis
Filtering
Merging
11/11/2018
Indian Institute of Technology, Kharagpur

7. Indian Institute of Technology, Kharagpur
DIFFERENT STAGES OF IMAGE SEGMENTATION
(a) (b) (c) (d)
(a) Original image (b) Image after clustering (c) Image after connected component analysis and (d) Final segmented Image
11/11/2018
Indian Institute of Technology, Kharagpur

8. Indian Institute of Technology, Kharagpur
IMAGE SEGMENTATION RESULTS
Natural Scene Images
11/11/2018
Indian Institute of Technology, Kharagpur

9. Indian Institute of Technology, Kharagpur
IMAGE SEGMENTATION RESULTS – CONTD.
Miscellaneous Images
11/11/2018
Indian Institute of Technology, Kharagpur

10. Indian Institute of Technology, Kharagpur
WEB BASED IMAGE RETRIEVAL APPLICATION
Query Specification
By Example Image
Display of Result Set
Nearest Neighbor Retrieval
External Image Upload
Utility to Upload External Image Files
11/11/2018
Indian Institute of Technology, Kharagpur

11. Relevant Set is not known for Large Uncontrolled Data Sets
PERFORMANCE MEASURE
Recall =
Precision =
Relevant Set is not known for Large Uncontrolled Data Sets
Perceived
Precision =
11/11/2018
Indian Institute of Technology, Kharagpur

12. Indian Institute of Technology, Kharagpur
RESULTS
Precision vs. recall on a controlled database of 2,015 images
Perceived precision variation on a large un-controlled
database of 28,168 images
11/11/2018
Indian Institute of Technology, Kharagpur

13. Indian Institute of Technology, Kharagpur
CONCLUSIONS AND FUTURE WORK
Effective way to capture Pixel Color Information using the HSV Color Space
Relative importance of Hue and Intensity determined based on Saturation
Pixel represented as True Color or Gray Color
Clustering of Image Pixels for Segmentation
Post-processing
Web-based Image Retrieval System
Perceived Precision for Testing on Large Data Sets
More Experiments and Comparative Studies being Carried out
New Distance Metrics
11/11/2018
Indian Institute of Technology, Kharagpur

14. Indian Institute of Technology, Kharagpur
Thank You
11/11/2018
Indian Institute of Technology, Kharagpur