- Form: BIN source [BIN=b] [BINR=br] [BINC=bc]
-
- $$
- [SR=sr] [SC=sc] [NORM]
- source
- is the image being compressed
- BIN=b
- compress rows and columns by integer factor 'b'
- BINR=br
- specify row compression
- BINC=bc
- specify column compression
- SR=sr
- give starting row of 'source' to locate region
being compressed
- SC=sc
- give starting column in 'source'
- NORM
- output is average of pixel values instead of sum.
BIN compresses images by integer factors. Adjacent pixels are added
together.
Use BIN= to specify a single compression factor for both rows and columns,
or use BINR and BINC to specify the compression for rows and columns
individually. For spectra, just use BIN. Note that
- BINR
- gives the amount by which rows or compressed. This
shortens each row, thus producing an image with
fewer columns in it.
- BINC
- gives the amount by which columns are compressed.
This shortens each column, thus producing an image
with fewer rows in it.
NORM makes the program AVERAGE adjacent pixels when compressing the image,
instead of the default summing of pixel intensities.
BSR and BSC specify the starting row and column, respectively, of the
region being saved. These are pixel locations in the original image. They
are used to compress and save only part of an image.
The output image ALWAYS has starting row 0 and starting column 0. It does
not make sense to use BIN on a wavelength-calibrated spectrum.
Examples:
- BIN 4 BIN=2
- compresses image 4 by a factor of 2
in rows and columns. Adjacent pixels
are added. The mean of the image will
be about 4 times the mean before
compression.
- BIN 3 BINR=6
- shortens each row in image 3 by a
factor of 6.
- BIN 4 BIN=5 SR=200 SC=400
-
takes the part of the image running
from row 200 to the end and from
column 400 to the end, and compresses
it by a factor of 2. The pixels
before row 200 and column 400 are
dropped from the image.