public void TestNormalizePixelData16Signed()
{
const int bitsAllocated = 16;
var bitsStored = 16;
var highBit = 15;
var pixelData = ShortToBytes(0, 32767, -32768);
var expected = (byte[])pixelData.Clone();
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "16-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 15;
highBit = 14;
pixelData = ShortToBytes(0, BinaryToShort("0100000000000000"), BinaryToShort("0011111111111111"));
expected = ShortToBytes(0, BinaryToShort("1100000000000000"), BinaryToShort("0011111111111111"));
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "16-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 15;
highBit = 15;
pixelData = ShortToBytes(0, BinaryToShort("1111111111111110"), BinaryToShort("0111111111111110"));
expected = ShortToBytes(0, BinaryToShort("1111111111111111"), BinaryToShort("0011111111111111"));
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "16-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 12;
highBit = 14;
pixelData = ShortToBytes(0, BinaryToShort("1111111111111111"), BinaryToShort("0111111111111110"));
expected = ShortToBytes(0, BinaryToShort("1111111111111111"), BinaryToShort("1111111111111111"));
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "16-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
}
/// <summary>
/// Normalizes grayscale pixel data by masking out non-data bits and shifting the data bits to start at the lowest bit position.
/// </summary>
/// <remarks>
/// <para>
/// The pixel data is normalized such that the effective high bit is precisely 1 less than bits stored.
/// Filling of the high-order non-data bits is performed according to the sign of the pixel value when
/// the pixel representation is signed, and always with 0 when the pixel reresentation is unsigned.
/// </para>
/// <para>
/// The provided <paramref name="dicomAttributeProvider"/> is <b>not</b> updated with the effective high bit,
/// nor is the <see cref="DicomTags.PixelData"/> attribute updated in any way. The only change is to the given
/// pixel data buffer such that pixels can be read, 8 or 16 bits at a time, and interpreted immediately as
/// <see cref="byte"/> or <see cref="ushort"/> (or their signed equivalents <see cref="sbyte"/> and <see cref="short"/>).
/// </para>
/// </remarks>
/// <param name="dicomAttributeProvider">A dataset containing information about the representation of pixels in the <paramref name="pixelData"/>.</param>
/// <param name="pixelData">The pixel data buffer to normalize (for 16-bit samples, the data should be in machine order).</param>
protected internal static void NormalizeGrayscalePixels(IDicomAttributeProvider dicomAttributeProvider, byte[] pixelData)
{
//TODO (CR Orion): these are retrieved again with default values directly below.
if (dicomAttributeProvider[DicomTags.BitsAllocated].IsEmpty)
{
const string msg = "BitsAllocated must not be empty.";
throw new ArgumentNullException("dicomAttributeProvider", msg);
}
if (dicomAttributeProvider[DicomTags.BitsStored].IsEmpty)
{
const string msg = "BitsStored must not be empty.";
throw new ArgumentNullException("dicomAttributeProvider", msg);
}
int bitsAllocated = dicomAttributeProvider[DicomTags.BitsAllocated].GetInt32(0, -1);
int bitsStored = dicomAttributeProvider[DicomTags.BitsStored].GetInt32(0, -1);
int highBit = dicomAttributeProvider[DicomTags.HighBit].GetInt32(0, bitsStored - 1);
bool isSigned = dicomAttributeProvider[DicomTags.PixelRepresentation].GetInt32(0, 0) > 0;
if (bitsAllocated != 8 && bitsAllocated != 16)
{
const string msg = "BitsAllocated must be either 8 or 16.";
throw new ArgumentException(msg, "dicomAttributeProvider");
}
if (bitsAllocated == 16 && pixelData.Length % 2 != 0)
{
const string msg = "Pixel data length must be even.";
throw new ArgumentException(msg, "pixelData");
}
if (highBit + 1 < bitsStored || highBit >= bitsAllocated)
{
highBit = bitsStored - 1; // #10029 - if high bit is out of range for some reason, just assume bits stored - 1 (which is probably the case for 99% of all DICOM images)
}
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, isSigned);
}
public void TestNormalizePixelData8Signed()
{
const int bitsAllocated = 8;
var bitsStored = 8;
var highBit = 7;
var pixelData = SByteToBytes(BinaryToSByte("10000000"), 0, BinaryToSByte("01111111"));
var expected = (byte[])pixelData.Clone();
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "8-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 7;
highBit = 6;
pixelData = new byte[] { 0, BinaryToByte("01000000"), BinaryToByte("00111111") };
expected = new byte[] { 0, BinaryToByte("11000000"), BinaryToByte("00111111") };
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "8-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 7;
highBit = 7;
pixelData = new byte[] { 0, BinaryToByte("11111110"), BinaryToByte("01111110") };
expected = new byte[] { 0, BinaryToByte("11111111"), BinaryToByte("00111111") };
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "8-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
bitsStored = 5;
highBit = 6;
pixelData = new byte[] { 0, BinaryToByte("11111111"), BinaryToByte("01111110") };
expected = new byte[] { 0, BinaryToByte("11111111"), BinaryToByte("11111111") };
DicomUncompressedPixelData.NormalizePixelData(pixelData, bitsAllocated, bitsStored, highBit, true);
AssertBytesEqual(expected, pixelData, "8-bit Signed (BitsStored={0} HighBit={1})", bitsStored, highBit);
}