| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 103 === In recent years, with the smart phone popularizing, the resolution of its built-in camera
is up to 500 million~1300 million pixels, it has gradually replaced the digital camera
and become the most popular portable device which was used to take pictures or video.
However, when using a smart phone to take pictures or videos, unlike a previously used
digital camera, sometimes skew distortion occurs in the screen. The key reason is the builtin
sensors of digital camera are mostly charge-coupled device(CCD), which take global
shutter mode to capture images, so that there will be no skew/wobble/partial exposure
effect. Handset developers choose complementary metal-oxide-semiconductor(CMOS)
sensor which used rolling shutter due to cost, and it will result in the above problems. The
paper analyzed skew distortion and come up with the improvement proposal.
Solutions proposed previously based on using skew parameter and global motion
vector(GMV) to automatically recover the skew screen, the disadvantages of which are
the selected GMV is easily misjudged in some cases.
In this thesis, the accelerometer data measured by g-sensor is converted into displacement,
it is equal to camera displacement,replacing the displacement GMV represents.
Skew parameter and camera displacement was used to fix skew distortion result from
rolling shutter CMOS sensor video in a quickly-moving camera directly, and rebuild the
missing pixels. Simulation results show that the proposed method effectively reduces the
skew distortion caused by rolling shutter.
Because camera offset could be easily converted through the acceleration into the
displacement, compared to the complex process to get GMV, it can not only effectively
reduce the complexity of the algorithm but also rule out the false positives probably caused
by the selection of GMV in a particular screen.
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