[BV] Finished assignment 8

Signed-off-by: Jim Martens <github@2martens.de>
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Jim Martens 2016-12-10 18:08:23 +01:00
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1.
------
| 1 |
-------------- ------
| 1 | -2 | 1 | + | -2 |
-------------- ------
| 1 |
------
The image has to be padded by 2 rows of zeros. The result of the correlation
follows:
---------------
| 1 | -2 | 1 |
---------------
|-2 | 4 | -2 |
---------------
| 1 | -2 | 1 |
---------------
The resulting filter is the result of the outer product of both used filters
which makes it a separable filter.
2.
The Prewitt edge detector for vertical edges follows:
-------------
|-1 | 0 | 1 |
-------------
|-1 | 0 | 1 |
-------------
|-1 | 0 | 1 |
-------------
The image of the exercise follows with 1 specifying white and 0 black.
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
| 0 | 0 | 0 | 1 | 1 | 1 |
-------------------------
The image has to be padded with 1 row and column of zeros to have a same size
result image. After that the convolution is applied. The padded image follows:
---------------------------------
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
---------------------------------
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
---------------------------------
The result of the convolution follows (without scalar product):
---------------------------
| 0 | 0 | -2 | -2 | 0 | 2 |
---------------------------
| 0 | 0 | -3 | -3 | 0 | 3 |
---------------------------
| 0 | 0 | -3 | -3 | 0 | 3 |
---------------------------
| 0 | 0 | -3 | -3 | 0 | 3 |
---------------------------
| 0 | 0 | -3 | -3 | 0 | 3 |
---------------------------
| 0 | 0 | -2 | -2 | 0 | 2 |
---------------------------
When the non zero values are replaced by ones, this is the result:
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
| 0 | 0 | 1 | 1 | 0 | 1 |
-------------------------
3.
-----
| 1 |
----- --------------
| 2 | * | -1 | 0 | 1 |
----- --------------
| 1 |
-----
To accurately process this convolution the image has to be padded by 2 columns
of zeros.
The result of the convolution follows:
--------------
| -1 | 0 | 1 |
--------------
| -2 | 0 | 2 |
--------------
| -1 | 0 | 1 |
--------------
This resulting filter is called Sobel edge detector for horizontal edges.