C*CTFFIND.FOR************************************************************
C                                                                       *
C       This program will attempt to determine the defocus (not yet     *
C       astigmatism) of any general image whether or not it contains    *
C       crystalline areas.  The program will also apply a CTF           *
C       correction either by multiplication or division (accompanied    *
C       by a Wiener filter).  Both amplitude and phase contrast with    *
C       astigmatism can be applied.                                     *
C                                                                       *
C         The input and output are Fourier transforms                   *
C                                                                       *
C       Card input - four cards only                                    *
C                                                                       *
C       1. IFIND,IAPPLY,IMULT,CTFMINMOD,WAMP - function control         *
C                                               (e.g.  F T T 0.2 0.07)  *
C       2. DFMID1 DFMID2 ANGAST - defocus estimate                      *
C       3. DSTEP XMAG CS KV     - image parameters                      *
C       4. RESMIN RESMAX        - resolution limits to explore          *
C                                                                       *
C       Logical I/O assignments are:                                    *
C                                                                       *
C       IN                      input image transform                   *
C       OUT                     output of ctf-corrected                 *
C                                                                       *
C       Version   1.00  9.7.94          RH      original program        *
C       Version   1.01  5.3.95          RH      debug O/P title         *
C       Version   1.02 12.7.96          RH      use RESMIN              *
C       Version   2.00 28.5.99          RH      add IMULT,CTFMINMOD,WAMP*
C                      08.6.04          JMS     increased ARRMXSIZ      *
C                                                                       *
C-----------------------------------------------------------------------*
C                                                                       *
C IFIND     - CARRY OUT CTF DETERMINATION AND REFINEMENT, USING         *
C              STARTING VALUES IF GIVEN - tries from half to double the *
C              given defocus using the given astigmatism as a guide to  *
C              the possible range and therefore rapidity of angular     *
C              variation                                                *
C IAPPLY    - APPLY CTF, USING INPUT OR REFINED PARAMETERS              *
C IMULT     - IF 'T' multiply by CTF, if 'F' divide by CTF              *
C CTFMINMOD - Minimum modulus of CTF to be used in denominator if       *
C              IMULT='F'.  This is similar to the normal Wiener filter  *
C WAMP      - Amplitude Contrast: e.g. 0.07(120kV), 0.04(200kV), etc    *
C ISIZE     - SIZE OF DENSITOMETERED ARRAY (E.G. 2000, 6000)            *
C DFMID1    - DEFOCUS LEVEL (UNDERFOCUS +VE). IF DFMID2=DFMID1, IMAGE   *
C DFMID2    -  IS NON-ASTIGMATIC. OTHERWISE AMOUNT OF DEFOCUS IN TWO    *
C              ORTHOGONAL DIRECTIONS, DFMID1 BEING DEFOCUS IN DIRECTION *
C              ANGAST (DEG) RELATIVE TO X AND Y OF THE FOURIER TRANSFORM*
C DSTEP     - DENSITOMETER STEPSIZE IN MICRONS                          *
C XMAG      - PRECISE MAGNIFICATION                                     *
C CS        - SPHERICAL ABERRATION IN MM                                *
C KV        - E.M. ACCELERATING VOLTAGE                                 *
C RESMIN    - RESOLUTION LIMITS TO BE USED IN ANGSTROMS                 *
C RESMAX    -    "  "                                                   *
C                                                                       *
C************************************************************************