Hi,
I'm trying to use HDF5DotNet to write some grayscale pictures provided by
special camera and saved in TIFF format. Each color component is 16 bits (
2Bytes for R, 2Bytes for G, 2Bytes for B).
I have no problem to store some INDEXED or TRUECOLOR pictures but I
have not managed
to write properly these pictures.
I created a dataset that contain the picture matrix with values between 0
and 65535. (so datatype is H5T.H5Type.NATIVE_USHORT).
i wrote attributes like:
1. CLASS = IMAGE
2. IMAGE_SUBCLASS = IMAGE_GRAYSCALE
3. IMAGE_VERSION = 1.2
I need to keep the precision of the 16-bit encoding for further work but
how to view these images in HDFView with a default palette with min and max
set to [0,255].
- A value of 0 for black color.
- A value of 65535 for white color.
If I set all pixel values to 30 000 the picture becomes black.
If I set all pixel values to 0 the picture becomes black.
So, how can I process to make link between the 16-bit coded value and the
256-color palette ?
Here a piece of code for generating a test picture:
ushort[,] dset_data48bit = new ushort[500, 500];
for (int i = 0; i < 500; i++)
{
for (int j = 0; j < 500; j++)
{
dset_data48bit[i, j] = 0;
}
}
The "dset_data48bit" array is passed as an argument of the method make_image
//Creation of the picture
public int make_image(H5FileOrGroupId a_oFileId, string a_strImageName, int
a_width, int a_height, ushort[,] a_valeurImage)
{
H5DataSetId oDataSetId = null;
int resRetour = -1;
long[] dims = new long[IMAGE8_RANK];
/* On initialise les dimensions de l'image */
dims[0] = a_height;
dims[1] = a_width;
try
{
/* Make the dataset */
oDataSetId = make_dataset_image(a_oFileId, a_strImageName,
IMAGE8_RANK, dims, H5T.H5Type.NATIVE_USHORT, a_valeurImage);
/* Attach the CLASS attribute */
WriteAttribute_String(oDataSetId, "CLASS", "IMAGE");
/* Attach the VERSION attribute */
WriteAttribute_String(oDataSetId, "IMAGE_VERSION", "1.2");
/* Attach the IMAGE_SUBCLASS attribute */
WriteAttribute_String(oDataSetId, "IMAGE_SUBCLASS",
"IMAGE_GRAYSCALE");
H5DataSpaceId oDataSpaceId = null;
H5AttributeId oAttributeId = null;
H5DataTypeId oDataTypeId = null;
ushort[] tBuffer = {0,65535}; // ushort limit
long[] dimension = { 2 };
oDataSpaceId = H5S.create_simple(1, dimension);
oDataTypeId = H5T.copy(H5T.H5Type.NATIVE_USHORT);
oAttributeId = H5A.create(oDataSetId, "IMAGE_MINMAXRANGE",
oDataTypeId, oDataSpaceId);
H5A.write(oAttributeId, oDataTypeId, new
H5Array<ushort>(tBuffer));
if (oDataSpaceId != null) H5S.close(oDataSpaceId);
if (oAttributeId != null) H5A.close(oAttributeId);
}
catch { }
finally
{
if (oDataSetId != null) H5D.close(oDataSetId);
}
return resRetour;
}
//Creation of the DataSet for the picture
public H5DataSetId make_dataset_image(
H5FileOrGroupId a_oLocId, string a_strDataSetName, int rank, long[] dims,
H5T.H5Type a_H5Type, ushort[,] data)
{
H5DataSpaceId oDataSpaceId = null;
H5DataSetId oDataSetId = null;
H5DataTypeId oDataTypeId = null;
try
{
//// Open an HDF5 file.
//oFileId = H5F.open(strHdf5FilePath,
H5F.OpenMode.ACC_RDWR);
// Create dataspace. Setting maximum size to NULL sets the
maximum
// size to be the current size.
oDataSpaceId = H5S.create_simple(rank, dims);
if (oDataSpaceId != null)
oDataSetId = H5D.create(a_oLocId, a_strDataSetName,
a_H5Type, oDataSpaceId);
oDataTypeId = H5T.copy(a_H5Type);
// Write the data to the dataset.
if (oDataSetId != null)
H5D.write(oDataSetId, oDataTypeId, new
H5Array<ushort>(data));
}
catch
{
}
finally
{
if (oDataSpaceId != null) H5S.close(oDataSpaceId);
if (oDataTypeId != null) H5T.close(oDataTypeId);
}
return oDataSetId;
}
Thank you and don't hesitate to ask for additionnal informations (I'm not
fluent in english) !
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