The routine first finds the brightest and darkest pixel values required by the particular scaling method in use. It then uses these to determine suitable scaling factors and converts the image into an 8-bit representation which is then output to a simple greyscale TIFF-6.0 file.
If the ‘high’ scaling value is less than the ‘low’ value, the output image will be a negative. Bad values are set to 0 for positives and 255 for negatives.
|ndf2tiff in out [scale]|
"Scale". All larger array values are set to 255 when HIGH is greater than LOW, otherwise all array values less than HIGH are set to 255. The dynamic default is the maximum data value. There is an efficiency gain when both LOW and HIGH are given on the command line, because the extreme values need not be computed. The highest data value is suggested in prompts.
.sdfextension). The suggested default is the current NDF if one exists, otherwise it is the current value.
"Scale". All smaller array values are also set to 0 when LOW is less than HIGH, otherwise all array values greater than LOW are set to 0. The dynamic default is the minimum data value. There is an efficiency gain when both LOW and HIGH are given on the command line, because the extreme values need not be computed. The lowest data value is suggested in prompts.
VERBOSE. If set to verbose, the scaling limits used will be displayed.
.tifname extension is added to any output filename that does not contain it. Any existing file with the same name will be overwritten.
[25,75]would scale between the quartile values. It is only required if SCALE is
SCALE = LITERAL (Read)
"Range"— The image is scaled between the minimum and maximum data values. (This is the default.)
"Faint"— The image is scaled from the mean minus one standard deviation to the mean plus seven standard deviations.
"Percentiles"— The image is scaled between the values corresponding to two percentiles.
"Scale"— You define the upper and lower limits between which the image is to be scaled. The application suggests the maximum and the minimum values minimum values when prompting.
"Sigmas"— The image is scaled between two standard-deviation limits.
"Sigmas". The standard-deviation bounds that define the scaling limits. To obtain values either side of the mean both a negative and a positive value are required. Thus
[-2,3]would scale between the mean minus two and the mean plus three standard deviations.
[3,-2]would give the negative of that.
old.sdf) to the TIFF file called
horse.sdf) into a TIFF file
horse.tifusing percentile scaling. The user will be prompted for the percentiles to use.
No compression is applied.