unstep -- Consolidate an image that has data divided among different groups.
unstep inimage outimage stepvar mix
This task copies an image and reformats the copy so that the number of groups is divided by n (the stepping factor) and each group is n times longer. The manner in which groups are combined depends upon the value of mix, as described below. The number of groups copied from the input image must be a multiple of the stepping factor.
- inimage [file name]
- A name of a one dimensional image whose data is "stepped" so that data elements appear in different groups.
- outimage [file name]
- A name for the output image in which the data from several groups has been combined into one large group.
- stepvar [string]
- The number of groups among which the pixels are divided. This can be either a number representing the actual stepping factor, or the name of a variable in the image header from which the stepping factor will be retrieved.
- mix [boolean]
- Read the first pixel from the first group, second pixel from the second
group, etc.? This determines how groups are combined. If mix=yes,
the first pixel in the first input group is written to the first pixel
in the first output group, the first pixel in the second input group is
written to the second pixel in the first output group, and so on, until
the stepping factor is reached, afterwhich, the second pixel in the
first input group is written to the next pixel in the first output
group. If mix=no, the first stepvar groups are concatenated. For
example, if stepvar is set to 2, the first group in the input image is
written to the first half of the first group in the output image and the
second group in the input image is written to the second half of the
first group in the output image.
1. Unstep the data in ydl0020 and put it in ydm0020. The stepping factor is contained in the header variable YSTEPS. The default extensions for image files, .hhh and .hhd, will be used. The output image will contain all the groups from the input image concatenated one behind another:
to> unstep ydl0020 ydm0020 ysteps no