User manual

Small Vision System User Manual 58
5.5 Acquisition Classes
svsAcquireImages
Base class for all acquisition
svsVideoImages
Acquire from a video source
svsFileImages
Acquire from a file source
SvsStoredImages
Acquire from a memory sourcde
Acquisition classes are used to get stereo image data from video or file sources, and put it into
svsStereoImage structures for further processing. During acquisition, images can be rectified, that is,
put into a standard form with distortions removed. Rectification takes place automatically if the calibration
parameters have been loaded into the acquisition class.
The two subclasses acquire images from different sources.
svsVideoImages uses the capture
functions in the loaded
svsgrab DLL to acquire images from a video device such as the MEGA-D stereo
head. svsFileImages acquires images from BMP files stored on disk.
5.5.1 Constructor and Destructor
svsAcquireImages();
virtual ~svsAcquireImages();
These functions are usually not called by themselves, but are implicitly called by the constructors for
the subclasses
svsVideoImages and svsFileImages.
5.5.2 Rectification
bool HaveRect();
bool SetRect(bool on);
bool GetRect();
bool IsRect();
bool ReadParams(char *name);
bool SaveParams(char *name);
These functions control the rectification of acquired images.
HaveRect() is true when rectification
parameters are present; the normal way to input them is to read them from a file, with ReadParams().
The argument is a file name, usually with the extension
.ini. If the acquisition object has rectification
parameters, they can be saved to a file using
SaveParams().
Rectification of acquired images is performed automatically if
HaveRect() is true, and rectification
processing has been turned on with SetRect(). Calling ReadParams() will also turn on
SetRect()
. The state of rectification processing can be queried with GetRect().
If the current image held by the acquisition object is rectified, the IsRect() function will return
true.
5.5.3 Controlling the Image Stream
bool CheckParams()
bool Start()
bool Stop()
svsStereoImage *GetImage(int ms)