This is a FORTRAN version of the C code written for the transputer rebinning. Here is the C description: Initialise the BESSEL weighting function for Bessel interpolation. The 1-D function 2.0$\ast$J1(x)/x is initialised in the declaration, and the weighting function lookup table is calculated from this. The tabulation is at intervals of pi/RES for the range 0.0 to RADIUS$\ast$pi, resulting in (RES$\ast$RADIUS)$\ast$$\ast$2 values. The weight function is also multiplied by a cosine over the oute third to reduce edge effects.

The look up table is initialised such that one can access the weight directly given the square of the distance between the input and output pixel. We use a fixed resolution out to 10PI.

CALL SCULIB_BESSEL_WTINIT( WTFN, RADIUES, RES, STATUS)

WTFN ( RADIUS $\ast$ RADIUS $\ast$ RES $\ast$ RES $+$ 1) = REAL (Returned)

RADIUS = INTEGER (Given)

RES = INTEGER (Given)

STATUS = INTEGER (Given & Returned)

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