file_pgm - writes intensity distribution into a pgm file.

Calling Sequence

[field_out]=file_pgm(field_in,fnam[,time[,gamma[,imax[,max_val]]]])

Parameters

• field_in :input field. it must be diffractive wavefront.
• fnam : the output filename, it must be a string.
• time : the timestamp of the outfile name. default time = -1. If the value of time is not positive,then the timestamp of the outfile will not be included.
• gamma : the value of contrast correction constant, default gamma=2.0. higher G gives better contrast in low intensities,
• imax : the grid dimension or sampling dimension (must be integer), default imax=128. it equals to grid sampling if you pass the zero to imax
• max_val : the number of gray levels (integer), default max_val=255 .
• field_out : the output field or diffractive wavefront.

Description

write the intensity distributions of a field into a pgm file. Files produced with file_pgm can be imported by a popular X graphical program XV, which saves to many other formats and allows for different conversions. Pgm stays for ''portable graymap'' and can be converted to other formats with netpbm or pbmplus packages. Files produced with file_pgm can also be imported by the Scilab function fil_ter . The gamma parameter for outfiles that are saved for further used has to be set to 1 (as mentioned before, the default is 2).

Examples

	F1=begin(0.01,1e-6);
	F2=gauss(F1,0.004);
	
	file_pgm(F2,"file1");	
	file_pgm(F2,"file2",1);	
	file_pgm(F2,"file3",-1,3);	
	file_pgm(F2,"file4",-1,3,0);	
	file_pgm(F2,"file5",-1,3,64);	
	file_pgm(F2,"file6",-1,3,64,100);	
 

Author

Chen jingyuan, Gan guangyong (IAPCM, Beijing,China.)

See Also

dwf_fits ,   file_ps ,   file_int ,   file_pha ,   cros_out ,