TcvPipeline

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TcvPipeline is a chain of Mat → Mat stages. Each stage is a Stages item with StageType and parameters in Operation. Errors are handled by ErrorPolicy (default: passthrough of the original frame).

Infrastructure

Property / API	Description
ProcessEveryN	process every N-th frame
ErrorPolicy	epPassthrough, epSkipStage, epStop
Preset	quick chain load (table below)
SaveToIni / LoadFromIni	stage type + Enabled (operation params — OI/code)
OnBeforeStage / OnAfterStage	Cancel in OnBeforeStage skips the stage
OnStageTiming	stage time in ms

Presets

Preset	Stages
ppEdges	Color → Blur(5) → Canny(80/160)
ppNightVision	CLAHE → BrightnessContrast(1.2, +10)
ppDenoiseSharp	Denoise → Sharpen
ppContours	Color → Contours
ppMotionDetect	BackgroundSubtract
ppLines	HoughLinesP
ppOpticalFlow	OpticalFlow
ppGrabCut	GrabCut

Stages (63 types)

Color, Blur, Threshold, Canny, Morphology, Resize, Custom, AdaptiveThreshold, BilateralFilter, EqualizeHist, Sobel, Invert, Clahe, InRange, MorphologyEx, ColorMap, BrightnessContrast, PyrDown, PyrUp, Laplacian, Scharr, Denoise, DistanceTransform, Crop, Normalize, Sharpen, Bitwise, Rotate, WarpPolar, Filter2D, CornerHarris, TemporalBlend, MatchTemplate, Contours, ChannelExtract, Flip, OrthoRotate, Gamma, AddWeighted, PyrMeanShift, SepFilter2D, SqrBoxFilter, SpatialGradient, CornerMinEigenVal, Integral, AbsDiff, AutoContrast, MergeChannels, Inpaint, Undistort, Remap, CustomLUT, HoughLinesP, HoughCircles, ConnectedComponents, BackgroundSubtract, DebugText, PhaseCorrelate, BlendLinear, ReferenceDiff, OpticalFlow, RunningAvg, GrabCut, Watershed.

Stage enhancements

Color (ColorPreset: Gray/HSV/Lab/RGB) · Canny (L2gradient) · Morphology/MorphologyEx (BorderMode, BorderValue) · InRange (Red/Green/Blue HSV presets) · Resize (ResizeMode=Scale, ScaleX/ScaleY, KeepAspect).

Overlay and analysis events

Stage	Event	Data
MatchTemplate	OnMatchResult	max val, point
Contours	OnContoursResult	contour count
HoughLinesP	OnHoughLinesResult	line segments
HoughCircles	OnHoughCirclesResult	x, y, r
ConnectedComponents	OnConnectedComponentsResult	LabelId, area, rect
BackgroundSubtract	OnForegroundMaskResult	foreground fraction
PhaseCorrelate	OnPhaseCorrelateResult	shift, response
OpticalFlow	OnOpticalFlowResult	mean magnitude

DrawOverlay (default True) draws markup on the frame; events provide metrics without drawing.

ConnectedComponents — ColormapSeed

When DrawOverlay=False, output is a JET colormap of labels.

ColormapSeed	Behavior
0 (default)	normalize by MaxVal; colors may shift when blob count changes
≠ 0	stable index (LabelId * Seed) mod 254 + 1

BackgroundSubtract (MOG2 / KNN)

API	Description
Reset	explicit background model reset
ResetOnAssign	default True: Assign resets the model; False — parameters only
setters Algorithm, History, …	recreate the subtractor

Tier 3 — stateful / second input

Stage	Notes
TemporalBlend	EMA (accumulateWeighted)
AbsDiff	diff with previous frame
AddWeighted, Bitwise, Inpaint, MergeChannels	OperandPath / MaskPath / channel files
BlendLinear	OperandPath + Weight1/Weight2
ReferenceDiff	ReferencePath + absdiff
OpticalFlow	Farneback; Output: HSV / magnitude / overlay
RunningAvg	accumulate, average since session start
GrabCut	ROI rect; mask / foreground / overlay
Watershed	markers: border=BG, rect=FG
DebugText	putText + optional rectangle

Example

Pipeline1.Stages.Add.StageType := stClahe;
Pipeline1.Stages.Add.StageType := stCanny;
Pipeline1.Preset := ppMotionDetect;

with TcvBackgroundSubtractOperation(Pipeline1.Stages[0].Operation) do
begin
  Algorithm := bsMOG2;
  OnForegroundMaskResult := OnFg;
end;

Demo: Test/Utit2. Code examples: Cookbook