Add data type conversions for analog input

Author: glopesdev

OpenEphys.Onix/OpenEphys.Onix/AnalogInput.cs

@@ -16,9 +16,15 @@ public class AnalogInput : Source<AnalogInputDataFrame>
 
         public int BufferSize { get; set; } = 100;
 
+        public AnalogIODataType DataType { get; set; } = AnalogIODataType.S16;
+
         public unsafe override IObservable<AnalogInputDataFrame> Generate()
         {
             var bufferSize = BufferSize;
+            var dataType = DataType;
+            var depth = dataType == AnalogIODataType.Volts ? Depth.F32 : Depth.S16;
+            var scale = dataType == AnalogIODataType.Volts ? AnalogIO.VoltsPerDivision : 1;
+            var shift = 0.0;
             return Observable.Using(
                 () => DeviceManager.ReserveDevice(DeviceName),
                 disposable => disposable.Subject.SelectMany(deviceInfo =>
@@ -39,7 +45,13 @@ public unsafe override IObservable<AnalogInputDataFrame> Generate()
                                 clockBuffer[sampleIndex] = frame.Clock;
                                 if (++sampleIndex >= bufferSize)
                                 {
-                                    var analogData = BufferHelper.CopyBuffer(analogDataBuffer, bufferSize, AnalogIO.ChannelCount, Depth.S16);
+                                    var analogData = BufferHelper.CopyConvertBuffer(
+                                        analogDataBuffer,
+                                        bufferSize,
+                                        AnalogIO.ChannelCount,
+                                        depth,
+                                        scale,
+                                        shift);
                                     observer.OnNext(new AnalogInputDataFrame(clockBuffer, hubSyncCounterBuffer, analogData));
                                     hubSyncCounterBuffer = new ulong[bufferSize];
                                     clockBuffer = new ulong[bufferSize];

OpenEphys.Onix/OpenEphys.Onix/BufferHelper.cs

@@ -21,5 +21,25 @@ public static Mat CopyBuffer<TBuffer>(
             CV.Transpose(bufferHeader, amplifierData);
             return amplifierData;
         }
+
+        public static Mat CopyConvertBuffer<TBuffer>(
+            TBuffer[] buffer,
+            int sampleCount,
+            int channelCount,
+            Depth depth,
+            double scale = 1,
+            double shift = 0)
+            where TBuffer : unmanaged
+        {
+            using var bufferHeader = Mat.CreateMatHeader(
+                buffer,
+                channelCount,
+                sampleCount,
+                depth,
+                channels: 1);
+            var data = new Mat(bufferHeader.Rows, bufferHeader.Cols, bufferHeader.Depth, 1);
+            CV.ConvertScale(bufferHeader, data, scale, shift);
+            return data;
+        }
     }
 }

OpenEphys.Onix/OpenEphys.Onix/ConfigureAnalogIO.cs

@@ -162,6 +162,7 @@ static class AnalogIO
 
         // constants
         public const int ChannelCount = 12;
+        public const double VoltsPerDivision = 0.00030517578125;
 
         // managed registers
         public const uint ENABLE = 0;
@@ -203,4 +204,10 @@ public enum AnalogIODirection
         Input = 0,
         Output = 1
     }
+
+    public enum AnalogIODataType
+    {
+        S16,
+        Volts
+    }
 }