compare with one point measure.ppt

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Measurement of Mandibular Cortical Width on Dental Panoramic Radiograph

Objective

To develop a computer aided system for measuring mandibular cortical width between the margins of cortical bone continuously on dental panoramic radiograph ,and clarify the diagnostic efficacy of the system

Femoral neck

Lumbar spine

Normal

Porous

Schematic Diagram of measuring cortical width

I.Region of Interest determination

a.Contrast Stretchingb.Determining mental foramenc. cropping area around mental foramen

II. Image Enhancement

a. Thresholding Algorithmb. High pass filtering

III. Cortical margin Identificationa. Distance Functionb.Thresholdingc.Closing and Openingd.Distance Functione. Inverting imagef. Dynamic Programmingg. Maskingh. Inserting DiscI. Finding upper and lower boundary

IV.Distance Measurement

a.Smoothingb. Polynomial Function

RightLeft

Contrasting ImageOriginal Image

Right

Distance functionHigh pass Filter

Closing &opening

Thresholding

Thresholding Filtering

Distance Function Inverting Image Dynamic Programming

Smooth & Tangentline Disc Fitting Masking

Distance functionHigh pass Filter

Filtering

ThresholdingThresholding

Closing &opening Thresholding

Left

Distance Function Masking

Disc FittingSmooth&Tangent

No. Image Right Left

1 1.tif 53.16 49.78

2 2.tif 37.28 26.12

3 3.tif 72.59 83.57

4 4.tif 39.87 38.56

5 5.tif 48.13 49.37

6 6.tif 57.49 56.28

7 7.tif 43.73 41.37

8 8.tif 30.01 30.61

9 9.tif 35.85 38.97

10 10.tif 39.70 39.27

11 11.tif 39.58 33.61

12 12.tif 32.09 40.97

13 14.tif 48.48 42.03

14 15.tif 47.34 39.92

No. Image Right Left

15 16.tif 35.59 36.22

16 17.tif 42.25 55.90

17 18.tif 28.12 30.18

18 19.tif 26.79 26.48

19 20.tif 49.20 51.54

20 21.tif 19.22 27.31

21 22.tif 27.93 34.43

22 35.tif 54.70 45.35

23 61.tif 22.05 25.31

24 62.tif 25.78 25.61

25 84.tif 27.23 30.13

Results- cortical width by pixels

Image Cortical Erosion

Cortical Width

1.tif 1 4.26

2.tif 3 2.22

3.tif 1 4.27

4.tif 1 6.04

5.tif 2 3.84

6.tif 1 4.66

7.tif 1 4.12

8.tif 2 3.42

9.tif 1 3.88

10.tif 2 4.63

11.tif 1 3.95

12.tif 2 3.07

14.tif 2 3.47

15.tif 1 6.48

16.tif 1 4.33

17.tif 1 4.9

18.tif 2 2.81

Image Cortical Erosion

Cortical Width

19.tif 1 2.57

20.tif 1 3.14

21.tif 3 2.39

22.tif 2 4.25

35.tif 2 3.94

61.tif 2 3.05

62.tif 1 4.33

84.tif 2 4.29

Previous Results

Computer-aided system

Right cortical width

Left cortical width

Threshold (pixels)

Sensitivity %

Specificity %

Threshold (pixels)

Sensitivity %

Specificity %

Lumbar spine 40 90 60 40 90 60

Femoral 37.5 80 73.3 41 90 53.3

Correlation of Computer-aided system with lumbar spine and femoral bone

Right cortical Left

Lumbar spine 0.47 0.65

Femoral 0.4 0.55

Right cortical Left

Lumbar spine 0.41 0.67

Femoral 0.44 0.58

Correlation of Manual measurement with lumbar spine and femoral bone

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