[media] doc-rst: add sh_mobile_ceu_camera crop documentation

Convert it to ReST and add it to media/v4l-drivers book.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2016-07-17 19:43:22 -03:00
parent ae9d2873a8
commit 9cbfcd7cf2
2 changed files with 30 additions and 28 deletions

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@ -34,4 +34,5 @@ License".
pxa_camera
radiotrack
saa7134
sh_mobile_ceu_camera
zr364xx

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@ -1,5 +1,7 @@
Cropping and Scaling algorithm, used in the sh_mobile_ceu_camera driver
=======================================================================
Cropping and Scaling algorithm, used in the sh_mobile_ceu_camera driver
=======================================================================
Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Terminology
-----------
@ -12,29 +14,31 @@ combined scales: sensor_scale * host_scale
Generic scaling / cropping scheme
---------------------------------
-1--
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-2-- -\
| --\
| --\
+-5-- . -- -3-- -\
| `... -\
| `... -4-- . - -7..
| `.
| `. .6--
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| . .6'-
| .´
| ... -4'- .´
| ...´ - -7'.
+-5'- .´ -/
| -- -3'- -/
| --/
| --/
-2'- -/
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-1'-
.. code-block:: none
-1--
|
-2-- -\
| --\
| --\
+-5-- . -- -3-- -\
| `... -\
| `... -4-- . - -7..
| `.
| `. .6--
|
| . .6'-
| .´
| ... -4'- .´
| ...´ - -7'.
+-5'- .´ -/
| -- -3'- -/
| --/
| --/
-2'- -/
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-1'-
In the above chart minuses and slashes represent "real" data amounts, points and
accents represent "useful" data, basically, CEU scaled and cropped output,
@ -134,6 +138,3 @@ Cropping is performed in the following 6 steps:
5. Calculate and apply host scale = (6' - 6) / (4' - 4)
6. Calculate and apply host crop: 6 - 7 = (5 - 2) * (6' - 6) / (5' - 5)
--
Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>