Integer type numbers

In the Huygens Software, integer type is one of the number representations used by the Huygens Compute Engine to describe VoXels intensities in an image. It is a signed 16 bit type. The valid range is therefore integers from -32768 to 32767.

Notice the difference between Huygens 16 bit mode, and TIFF file format 16 bit. Huygens' is signed (allowing positive and negative values), and Tiff's is unsigned (only positive values allowed). This implies a rescaling when exporting to TIFF: negative values, if existing, are lost, and the positive values are upscaled (multiplied by a factor larger than one) to make use of the available extra bit (see Tiff Scaling).

When reading 16 bit TIFF, which allow positive integers from 0 to 65535, a decision has to be taken: either the data is divided by two to make it fit the signed range while keeping it in integer format, or it is converted to 32 bit Float Type, which can store values higher than 32767.

In the most recent versions of Huygens Essential the 16 bit TIFF files are scanned while being read, allowing to rescale them only if really necessary and keeping the opened image in 16 bit Integer Type. This will be OK for most of the data that despite of being saved in 16 bit format actually come out from the microscope in 12 bit. If a rescaling is necessary, you will get a message like follows:

 The image intensity was divided by 2 to adapt the
data to the current image type.

In older versions, the default when in silent mode is to convert to Float Type, what uses more memory. In interactive mode a dialog may pop up, asking what to do, like follows

 Input file is in 16 bit TIFF format: select target data type:

  To float        To 16 bit signed        To 8 bit unsigned
(This is the Open Query Dialog)

If your microscope data was originally 8 or 12 bit saved in a 16 bit file this can be safely read as integer type, with values larger than 32767 clipped. This is the recommended option in order to save memory.

In Huygens Core you can control the conversion when opening an image with the img open by using the command options -foreignTo byte|int|float and -cmode clip|scale. See the Huygens Core Programmer Guide.

See Huygens Data Types.