An example of a Classification Process

We have defined a set of rules for classifying SUSI exposures according to the exposure type (BIAS, FF, SCI) and a set of rules for classifying them according to the optical path. (In this case, this consists simply in classifying the frames according to the filter number that was used.)
The MIDAS session shown in Table 15.5 creates these rules and applies them to our set of SUSI exposures (Table 15.3). The result of the classification process is illustrated in Table 15.6.
For convenience, one may also store all the classification parameters in a table (Table 15.7) and apply a set of classification rules in one step.
Note that instead of the interactive command CREATE/CRULE the equivalent command WRITE/DESCR may be used. The table must contain the following columns:

• :DESCR - character column
  Contains the names of the classification rules descriptors
• :OUTCOL - character column
  Contains the label of the output column of the OST in which the string flagging the exposures satisfying the corresponding rule should be stored.
• :OUTCHAR - character column
  Contains the character string for flagging the rows satisfying the corresponding rule.
  

In the session mentioned above, one can replace the four calls to the command
CLASSIFY/IMAGE by:

CLASSIFY/IMAGE susi_ost susi_rule.tbl

  

Table: Observation Summary Table with file classifications appended in column :EXPTYPE and :OPATH as defined and applied in Table 15.5

  

Table 15.7: Classification Table for SUSI exposures (susi_rule.tbl)