SightLine Applications Command, Control, and Script API  v3.5
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SLARegistrationParameters_t Struct Reference


Parameters used in frame to frame image registration matching.

typedef struct {
u8 cameraIndex;
u16 maxTranslation;
u8 maxRotation;
u8 zoomRange;
u16 left;
u16 right;
u16 top;
u16 bottom;
u8 updateRate;
u8 flags;

Registration matches frame to frame motion in offset, rotation and zoom. It is a critical first step for stabilization, tracking and detection. If poor performance in stabilization, tracking or detection is observed, it is often due to registration failures. The most common reasons for registration failure along with possible solutions are:

Ignore Edge Pixels

Used for overlays or foreground objects that appear near the edge of the image. 0 is default. At least 1/4 of the smaller dimension of the image must be remaining. For NTSC, remaining non - ignored image must be at least 120x120. Use the `ignore edge pixel band' to indicate that the registration algorithm should not include these pixels when determining the registration match. This can be used to compensate for effects of the optics such as vignetting or when there is an obstruction along an edge of the image. See SLASetOverlayMode_t to enable onscreen graphics to better select ignore edge bands.

To get values: SLAGetParameters_t, id=0x9E, payload1=[CameraIndex]. Returns SLARegistrationParameters_t.

Message ID 0x9E

Byte Offset Name Description
4cameraIndexCamera Index
5-6maxTranslationMaximum translation in pixels per frame. Default of 0 is equivalent to 120 for a 480 high image (1/4 of the image height).
NOTE: If you know that the maximum frame to frame translation is small, you can get faster speed with a smaller value here. Be careful not to limit it too much!
7maxRotationMaximum rotation range in degrees per frame: 0..10 (values larger than 10 clipped to 10). 5 is default..
NOTE: 5 is a good value for an airborne camera, it is rare to need more than 5 degrees per frame. 0 executes significantly faster and is a good value for a fixed mount camera that does not experience roll.
8zoomRangeMaximum zoom range in percent zoom per frame: 0..10. 0 is default.
NOTE: This parameter should almost always be 0. Small values may help in limited cases to maintain registration and tracking while a camera is actively zooming. Enabling this parameter when a camera is not zooming will make registration run slower with less accuracy.
9-10leftLeft band of edge pixels to ignore. (0 is default)
11-12rightRight band of edge pixels to ignore. (0 is default)
13-14topTop band of edge pixels to ignore. (0 is default)
15-16bottomBottom band of edge pixels to ignore. (0 is default)
17updateRatePercentage to update the model each frame. 0 to 100%. (10 is default)
100: recommended for moving cameras. (Stationary Camera Low Drift unchecked in Panel Plus)
10: for ground mounted cameras desiring low drift scene lock and Staring detection mode. (Stationary Camera Low Drift checked in Panel Plus)
18flagsRegistration Flags.
0-2Registration mode
0 = Default - software based registration
1 = Reserved
2 = Use passed in registration, software based registration will be skipped. (Only supported with Library. Not supported on 1500, 3000, 4000)
3-7 = Reserved