MV Polar DirectShow Filter
The MontiVision Polar DirectShow Filter is used to
transform polar 360° images or video frames into rectangles or
vice versa. This can for example be used to unwarp images from
panoramic surveillance cameras (see example below).
| File: |
Polar.ax |
| CLSID: |
CLSID_MVPolar |
Supported Interfaces
IMVPolar
IMVHistogram
IMVHistogram2
IMVHistogram3
IMVFilterData
IMVAbout
IMVFilterInfo
IBaseFilter
ISpecifyPropertyPages
IConnectionPointContainer
IPersistStream
Supported COM Events
The filter supports following events through the IMVFilterEvents interface.
Look at the filter events
page for more information.
| Event
|
Value
|
Description
|
| MV_ALGORITHM_START_EVENT |
0
|
A filter starts processing a video frame or sample. |
| MV_ALGORITHM_END_EVENT |
1
|
A filter finishes processing a video frame or sample. |
MV Polar Property Page
Uses the IMVPolar interface to setup the
filter.
| Initialization |
Sets the default parameters for the transformation
algorithm |
| Transformation |
Either "Rectangualt to Polar" or "Polar to Rectangular"
transform. This option can only be changed while the filters output
pin is unconnected. |
| Polar Image Origin |
Center location of the polar image
circle. |
| Polar Image Radius |
Inner and outer radius os the polar image. |
| Output Image Size |
Actual dimension fo the filters output video. |
| Flip Image |
Flips the output image vertically. |
| Reverse Image |
Flips the output image horizontically. |
| Start and End Angle |
Start and end angle of the polar image. This can be
used to crop a part of the polar image. By default both are zero,
which means that the whole circle is unwarped. |
| Interpolation |
Interpolation used by the transformation algorithm. |
Example: 360° Video Surveillance
Polar Video captured from a panorama surveillance camera:
Unwarped rectangualr video:
|