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Common/DTS.Common.Calculations/.svn/pristine/5f/5fbc097c29dec180bcab323bcb1ea389da1654ff.svn-base

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+using System;
+
+namespace DTS.Common.Calculations
+{
+    public class HeadInjuryCriterion
+    {
+        /// <summary>
+        /// Calculates the head injury criterion given a resultant channel, and a desired clip length
+        /// </summary>
+        /// <param name="resultant">Acceleration vector (x,y,z resultant)</param>
+        /// <param name="SPS">Actual sample rate</param>
+        /// <param name="clipLengthMS">Length in ms </param>
+        /// <returns>MAX Head Injury Criterion over the data input for the clip requested</returns>
+        public static HICResult GetHeadInjuryCriterion(ChannelData resultant, double SPS, int clipLengthMS)
+        {
+            System.Diagnostics.Trace.Assert(SPS > 0, "Actual sample rate must be positive");
+            System.Diagnostics.Trace.Assert(clipLengthMS > 0, "Clip length must be positive");
+
+            int maxHICPoint = int.MinValue;
+            double maxHIC = int.MinValue;
+            int maxHICEndPoint = int.MinValue;
+
+            int maxclip = Convert.ToInt32(Math.Ceiling(clipLengthMS * SPS / 1000D));
+
+            for (int clip = 1; clip <= maxclip; clip++)
+            {
+                System.Diagnostics.Trace.Assert(clip < resultant.FilteredEU.Length, string.Format("data must be atleast {0} ms", clipLengthMS));
+                double clipInSeconds = clip / SPS;
+                for (int i = 0; i < resultant.FilteredEU.Length - clip; i++)
+                {
+                    //note we are exhaustively recalculating sums, we can do this much better without a doubt, but lets get the
+                    //first method done (brute force)
+                    //also note, definite integral doesn't include last point, so we have to add one point back in
+                    double integral = Integral.DefiniteIntegral(resultant.FilteredEU, i, i + clip, SPS);
+                    double hic = clipInSeconds * Math.Pow(integral / clipInSeconds, 2.5D);
+                    if (hic > maxHIC) { maxHIC = hic; maxHICPoint = i; maxHICEndPoint = i + clip; }
+                }
+            }
+            return new HICResult(maxHIC, clipLengthMS, maxHICPoint, maxHICEndPoint);
+        }
+
+
+
+        /// <summary>
+        /// helper class for storing/handling hic results
+        /// </summary>
+        public class HICResult
+        {
+            public int StartSample { get; }
+            public int EndSample { get; }
+            public int HicLengthMS { get; }
+            public double HIC { get; }
+            /// <summary>
+            /// constructs a new HIC result
+            /// </summary>
+            /// <param name="hic">HIC value</param>
+            /// <param name="hicLength">length of HIC in ms</param>
+            /// <param name="endSample">start sample of HIC</param>
+            /// <param name="startSample">end sample of HIC</param>
+            public HICResult(double hic, int hicLength, int startSample, int endSample)
+            {
+                StartSample = startSample;
+                EndSample = endSample;
+                HicLengthMS = hicLength;
+                HIC = hic;
+            }
+        }
+    }
+}