Locating images

nXDS adopts two ways for specifying snapshot images for processing.

1. Image directory and list of file names

2. Generic file name template and image numbers

This way of specifying snapshot images by a template is also adopted for reading images by an external library routine whose full path name is provided by the input parameter LIB=. Use of such a dynamically linked library routine is indicated by the optional keyword GENERIC following the name template. In case of EIGER detector images the Neggia library from DECTRIS would be used which can retrieve images stored in a container structure.
If no external image reading routine is provided by the LIB= input parameter, nXDS relies on its internal routines denoted by the format keywords below.

Initially, on the first call of nXDS, a file named SHOTNUMBERS may not be available. In this case it will be generated from user input parameters like, for example,
DATA_RANGE=1 100000
EXCLUDE_DATA_RANGE= 6490 6556
In the example here, each line of the file SHOTNUMBERS has one number from the allowed ranges 1...6489, 6557...100000. An arbitrary number of EXCLUDE_DATA_RANGE parameters can be specified. If a file named SHOTNUMBERS is already available it will be used and any DATA_RANGE and EXCLUDE_DATA_RANGE parameters are ignored.

Image formats

For many of the detectors presently used the image format is recognized automatically by nXDS. A format keyword, like MAR or GENERIC is not needed. However, if the format is explicitly named, nXDS will attempt to read the snapshot images in the specified way. The format KEYWORD can be:

GENERIC

The actual reading of the image data is done by the external, dynamically linked library specified by the parameter LIB=name_of_external_library. This special software must be provided by the detector manufacturer and is independent from nXDS. The software is only supposed to somehow retrieve requested image data using the information from the given name template and the image number. The great flexibility of this method uncouples nXDS from new detector developments and image data representation.

CBF

Byte offset variant of the Crystallographic Binary Files format ( CBFlib );
PILATUS pixel detector format

MAR345

MAR555 and MAR345 image format

RAXIS

R-AXISII, R-AXISIV, or R-AXISV detector

CCP4

Compressed images by Jan Pieter Abrahams algorithm with number representation used at MRC

TIFF

TIFF-format used by CCDCHESS and MARCCD detectors

SMV

ADSC CCD-detector image data format;
R-AXIS4 and SATURN92 CCD-detector format;
NOIR-1 detector format;
CCD-detector (1024 X 1024) at Brandeis & Brookhaven;

MAR

old marresearch detector; BRANDEIS_B4 CCD detector

STOE

IPDS image data format (Stoe & Cie GmbH, D-Darmstadt)

BRUKER

Bruker AXS image data format for the SMART6000 CCD detector

HARVARD

SIEMENS multiwire detector