Shadow Detection of Color Aerial Images

1. SHADOW DETECTION OF
COLOR AERIAL IMAGES
Student:
1. Iva Nurwauziyah
2. Muhammad Irsyadi Firdaus
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2. SHADOW?
A shadow is a dark area where light from a light source is
blocked by an object.
Buildings,
Bridges,
Tower,
etc.
In the urban aerial image, shadow are usually caused by
elevated object when they are illuminated by the Sun.
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3. THE DISADVANTAGES
Shadow may cause loss of:
Feature information
False color
Failure of combine image
matching
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Shadow Detection

4. Input Aerial Image
Color Transformation
Ratio Map
Otsu Method of
Thresholding
Ratio Map > Thresholding
Non Shadow
Pixels
Shadow
Pixels
Shadow Map
YesNo
Morphological
Methodology

5. COLOR
TRANSFORMATIO
N
The input RGB
image into an
invariant color
model, i.e., HSI,
HSV, HCV, YIQ, or
Y CbCr color
models.

6. RATIO MAP
In the image segmentation process we calculated the ratio
between hue and intensity values of the pixels to obtain
shadows.

7. OTSU METHOD OF THRESHOLDING
Otsu’s Method (Otsu, 1979) is an automatic threshold
determination method, applied to the histogram of an image,
which separates the image into two classes (Shadow and
Non-shadow).
Such is an optimum threshold that maximizes the between-
class variance of the two histogram classes.

8. MORPHOLOGICAL
Images segmented by
thresholding often end up
leaving some noise in the
form of loose pixels.
We perform morphological
Closing to the shadow in
order to remove noise in the
final shadow.
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9. RESULTS
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Input color aerial image ratio map of (a)
Shadow detection result of (b)

10. Input Aerial Image
Color Transformation
Ratio Map
Otsu Method of
Thresholding
Ratio Map > Thresholding
Non Shadow
Pixels
Shadow
Pixels
Shadow Map
YesNo
Morphological Morphological operations
were used to reduce
shadow noise.
Appendix

11. REFERENCE
Kuo-Liang Chung, 2009, Efficient Shadow Detection of Color Aerial
Images Based on Successive Thresholding Scheme, IEEE Transactions
On Geoscience And Remote Sensing, Vol. 47, No. 2.
Guilherme F. Silva, 2017, Near real-time shadow detection and
removal in aerial motion imagery application, ISPRS Journal of
Photogrammetry and Remote Sensing.
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12. THANK YOU FOR YOUR ATTENTION
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