FTOREC

Introduction

FTOREC is designed to take all or part of a diffraction image and transform this portion of the image into reciprocal space, given knowledge of the specimen to film distance, rotation of the image, wavelength and tilt of the specimen. Either polar or cartesian reciprocal space output is available, the cartesian option being used by the program LSQINT for data reduction. Currently, the program will accept data either in standard BSL format or scanned film images renamed to BSL type filenames and given a BSL header. Absorption corrections are available for film data. Any pixels on the input image containing a negative will be rejected from the transformation and any pixels on the output image for which there is no information will be flagged with the number -1.0E+30. This allows for easy masking of unwanted portions of the image using a combination of the .MSK and .ADD options in BSL.

Input file

The path and filename of the input image data file(s) can be entered directly in the text window or selected by using the File Open Dialog Tool, which is opened by clicking the Browse button. If no path is specified, the current directory is searched.

File Selection.

For multi-frame BSL image user is able to select start, last and increment and the binary file type if there are more than one binary file exist.

Xfix Parameters.

These parameters must be input by the user to specify wavelength , sample to detector distance, detector centre, orientation, twist tilt, and sample tilt. The wavelength need specify in angstroms, sample to detector distance and detector centre are in pixels and orientation, twist, tilt, sample tilt in degree.

Output Type.

User can selecttransform image to reciprocal polar coordinates or reciprocal Cartesian coordinates by scrolling text. (Default Cartesian).

The reciprocal space limits

The reciprocal space limits DMIN , DMAX , RMIN, ZMIN for Cartesian coordinates and , DMIN , DMAX ,SIGMIN SIGMAX for polar coordinates can be set.

• DMIN - The minimum d* in the transformed image
• DMAX -The maximum d* in the transformed image
• RMIN - The minimum R in the transformed image
• ZMIN - The minimum Z in the transformed image
• SIGMin - The minimum Sigma in the transformed image.
• SIGMax - The maximum Sigma in the transformed image.
• (Defaults DMIN 0.0 DMAX 0.5 RMIN 0.0 ZMIN 0.0 SIGMIN 0.0 SIGMAX 90).

Maximum pixel value transformed

MAXOpt enables the use to set the maximum pixel value to be transformed.

(Defaults for film data MAXOpts 255.0, for area detector data MAXOpts 1.0E16).

BINS

This enables to set the output image size in pixel. The number of [R,Z] bins or the number of [D,Sigma] bins (Default BINS 256 256).

RATIO

The Y:X ratio of the pixel dimensions.(Default RATIO 1.0)

STEP

The step values for [R,Z] or [D,Sigma] (Default STEP dmax/max(bins(1),bins(2)) dmax/max(bins(2),bins(2)) for [R,Z], STEP dmax/bins(1) 90.0/bins(2) for [D,Sigma])

BACKstop

The maximum R,Z values for a rectangular backstop (Default BACKSTOP 0.0 0.0)

SIGMas

This forces a output of an image corresponding to the standard deviations of the values in the reciprocal space bins. The path and filename of the standard deviations output image can be entered directly in the text window or selected by using the File Save Dialog Tool, which is opened by clicking the "Browse" button. If no path is specified, the current directory is searched. Clicking Write Header button enables to write two lines of the header title for output BSL image file.

Image Potion

By changing pixel start , pixel last ,raster start and raster last part of diffraction image transform into reciprocal space.

FILM

Set input data type to scanned film. Currently this affects the way information from image space is binned into reciprocal space. Selecting Film enables Film Option button. Clicking Film Option button popup Film Option Dialog.

ABSOrption - Absortion coefficients for film data

PAPER - The absortion coefficient for black paper
EMULSION - The absorption coefficient for film emulsion
BASE - The absorption coefficient for the film base
(PAPER 0.0 EMULSION 0.4 BASE 0.2 ! If FILM has been set)

PRECEDING - Numbers for the preceding films and paper

PAPER -The number of papers in front of this film
FILM - The number of films in front of this one .
(Defaults PAPER 0 FILM 0) Text Window

This text area displays output from the process.

Output

The output file will be in standard BSL format except that the second header record will be used for storing information regarding the starting points and increments of the reciprocal space image. Pixels which are outside of the resolution range, off-sphere or saturated will be flagged with the value -1.0E+30.

The path and filename of the output image can be entered directly in the text window or selected by using the File Save Dialog Tool, which is opened by clicking the "Browse" button. If no path is specified, the current directory is searched. Clicking Write Header button enables to write two lines of the header title for output BSL image file.