NewGamePhysics.Mathematics.EdgeDetector Class Reference

Represents an edge detector. More...

List of all members.

Public Member Functions

 EdgeDetector (EdgeDetectionType detectionType, double threshold)
 Create a new instance of an edge detector.
double[] Calculate (double[] samples)
 Analyzes samples and returns new array with samples set to 1.0 where edges were detected. The absolute value of the input is normalized and binarized at the threshold.

Detailed Description

Represents an edge detector.

Definition at line 34 of file EdgeDetector.cs.

Constructor & Destructor Documentation

NewGamePhysics.Mathematics.EdgeDetector.EdgeDetector ( EdgeDetectionType  detectionType,
double  threshold 
)

Create a new instance of an edge detector.

Parameters:
detectionType The detection type (edge(s) to detect).
threshold The binarization threshold in the range 0.0 to 1.0 (against normalized input)

Definition at line 61 of file EdgeDetector.cs.

00062         {
00063             this.detectionType = detectionType;
00064             this.threshold = threshold;
00065         }

Member Function Documentation

double [] NewGamePhysics.Mathematics.EdgeDetector.Calculate ( double[]  samples  ) 

Analyzes samples and returns new array with samples set to 1.0 where edges were detected. The absolute value of the input is normalized and binarized at the threshold.

Parameters:
samples The samples to analyze.
Returns:
The detection result containing 0.0 (no edge) and 1.0 (edge) values.

Definition at line 77 of file EdgeDetector.cs.

00078         {
00079             int nMax = samples.Length;
00080             double[] result = new double[nMax];
00081 
00082             // Make absolute and determine maximum
00083             double maximum = Math.Abs(samples[0]);
00084             for (int i = 0; i < nMax; i++)
00085             {
00086                 double value = Math.Abs(samples[i]);
00087                 result[i] = value;
00088                 if (value > maximum)
00089                 {
00090                     maximum = value;
00091                 }
00092             }
00093 
00094             // Binarize
00095             double margin = maximum * this.threshold;
00096             for (int i = 0; i < nMax; i++)
00097             {
00098                 result[i] = (result[i] > margin) ? 1.0 : 0.0;
00099             }
00100 
00101             // Edge detect
00102             double lastValue = 0.0;
00103             for (int i = 0; i < nMax; i++)
00104             {
00105                 bool risingEdge = ((lastValue == 0.0) && (result[i] == 1.0));
00106                 bool fallingEdge = ((lastValue == 1.0) && (result[i] == 0.0));
00107                 lastValue = result[i];
00108                 switch (this.detectionType)
00109                 {
00110                     case EdgeDetectionType.Falling:
00111                         result[i] = (fallingEdge) ? 1.0 : 0.0;
00112                         break;
00113                     case EdgeDetectionType.Rising:
00114                         result[i] = (risingEdge) ? 1.0 : 0.0;
00115                         break;
00116                     case EdgeDetectionType.Both:
00117                         result[i] = (risingEdge || fallingEdge) ? 1.0 : 0.0;
00118                         break;
00119                 }
00120             }
00121 
00122             return result;
00123         }

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