iflRaw(3)

NAME

iflRaw - raw image file format

DESCRIPTION

This image file format is used to access raw image data stored in a file. The data must be organized in raster fashion; if the data is in pages then the pages must all be fixed size (with partial pages at the image edge padded to fill out the fixed size) and the pages must be ordered in raster fashion themselves.

The raw format supports the full flexibility of the IFL model: all data types, color models, orders, orientations and page sizes are supported. Like all file formats supported by IFL you access raw images via the generic object class (or the ilFileImg object for IL users).

The default extension for image files in the raw format is '.raw'. When you create a file with that extension IFL will assume you want the raw format, unless you override it with the iflFormat parameter or format suffix, '#<format-name>'.

SPECIFYING DATA FORMATTING

To read a file in raw format you must use the format override suffix, '#raw', and the format specific argument suffic, '%<format-specific- args>' to tell IFL what the data format is since it can't determine it from a file header. The data format is specified using a set of parameter name/value pairs separated by spaces or '%' as the format specific arguments. The paramter names and values may be abbreviated for convenience. For example, to open a luminance, unsigned char, 512 by 512 image in a file named 'image.raw' you would use the file specification:

image.raw#raw%size=512,512%colormodel=luminance

or (assuming the name is used on a command line in csh):

image.raw#raw%'s=512,512 c=lum'

The full set of parameters and their possible values are enumerated in the folowing sections.

size=<width>,<height>[,<depth>[,<components>]]
The size parameter specifies the image size. The depth (size of the Z dimension) defaults to 1 if omitted. If omitted, the number of components per pixel (size of the C dimension) defaults to the appropriate value for the color model specified.

pagesize=<width>,<height>[,<depth>[,<components>]]
The pagesize parameter specifies the page size. If omitted the values default to the same as the image size.

type=<data-type>
The type parameter specifies the data type of the pixel components. Possible values are:

     bit      data is single bit per component
     char     data is signed char (8-bit per component)
     uchar    data is unsigned char (8-bit); this is the default
     short    data is signed short (16-bit)
     ushort   data is unsigned short (16-bit)
     int      data is signed integer (32-bit)
     uint     data is unsigned integer (32-bit)
     float    data is float (32-bit floating point)
     double   data is float (64-bit floating point)
order=<dimension-order>
The order parameter specifies the ordering of the image dimensions, from most rapidly varying, to least rapidly varying. Possible values are:

interleaved
component dimension varies fastest, then x, then y, z last; thus all the components of each pixel are grouped together; this is the default

separate
x dimension varies fastest, then y, then components, z last; the data is stored with each component isolated in a separate plane.

sequential
x dimension varies fastest, then components, then y, z last; all the components of a single row are grouped together (seldom used)

orientation=<location-of-origin>
The orientation parameter defines the spatial interpretation of the images x and y dimensions. It is defined in terms of the location of the origin of the image (one of the four corners) and the direction of the x and y dimension (whether x runs horizontally or vertically). The combination of these two factors yields the eight orientations supported by this format:

tl
origin in top-left corner, x dimension is horizontal (y is vertical); this is the default value

     tr  origin in top-right corner, x dimension is horizontal
     bl  origin in bottom-left corner, x dimension is horizontal
     br  origin in bottom-right corner, x dimension is horizontal
     lt  origin in top-left corner, x dimension is vertical (y is horizontal)
     rt  origin in top-right corner, x dimension is vertical
     rb  origin in bottom-right corner, x dimension is vertical
     lb  origin in bottom-left corner, x dimension is vertical
colormodel=<interpretation-of-pixel-components>
The colormodel parameter defines the interpretation of the components of the image's pixels. The possible values are:

     luminance     single component greyscale
negative
single component inverted greyscale (minimum is white, maximum is black)

     la            two component luminance plus alpha
palette
single component color palette (indicies mapped through a color map)

     rgb           red, green, blue triplets; this is the default
rgba
RGB plus alpha (four components)

     hsv           hue, saturation, value (three components)
     cmy           cyan, magenta, yellow (three components)
     cmyk          cyan, magenta, yellow, black (four components)
ycc
intensity, red-chrominace, green-chrominance (three components)

mulitspectral arbitrary number of components, no interpretation (c size
must be given with size parameter)

offset=<offset-to-start-of-data>
The offset parameter gives the offset in bytes to the start of the image data. The default value is zero.

minimum=<min-value-for-display-scaling>
The minimum parameter specifies the minimum value in the data for display scaling purposes. The default is the minimum value for the component data type or zero for floating point data.

maximum=<max-value-for-display-scaling>
The maximum parameter specifies the maximum value in the data for display scaling purposes. The default is the maximum value for the component data type or one for floating point data.

SEE ALSO

iflFile, ilFileImg