step -- Divide image data between different groups.
step inimage outimage stepvar mix
This task copies an image, and reformats the copy so that the number of groups is multiplied by n (the stepping factor) and the size of each group is divided by n. The manner in which the groups are combined depends upon the value of mix, as described below.
- inimage [file name]
- A name of a 1-dimensional image in which the data from several groups has been combined into one large group.
- outimage [file name]
- A name of the output image whose data is "stepped" so that data elements appear in different groups.
- stepvar [string]
- The name or value of the stepping factor, i.e., the number of groups among which the pixels will be divided. If stepvar is a number, it is interpreted as the value of the stepping factor, otherwise it will be interpreted as the name of a variable in the image header whose value is the stepping factor.
- mix [boolean]
- Write the first pixel to the first group, second pixel to the second group, etc.? This determines how groups are combined. If mix=yes, the first pixel in the first group of the input is written to the first ouput group, the second pixel is written to the second output group, and so on, until the stepping factor is reached, after which the next pixel is again written to the first output group. If mix=no, the input groups are divided into consecutive regions which are written to the output groups. Thus if stepvar equals 2, the first half of the first group in the input image is written to the first output group and the second half of the first group in the input image is written to the second group.
1. Step the data in ydl0020 and put it in ydm0020. The stepping factor is contained in the header variable YSTEPS. The output image will contain all the groups from the input image divided into consecutive regions:
to> step ydl0020.hhh ydm0020.hhh ysteps no