pnminterp

Interpolate image (scale up)

$ pnminterp [factor] [input.pnm] > [output.pnm]

$ pnminterp 2 [input.pnm] > [output.pnm]

$ pnminterp 3 [input.pnm] > [output.pnm]

pnminterp n [file]

pnminterp enlarges PNM images by an integer factor using bilinear interpolation. Unlike simple pixel replication (as done by pnmenlarge), interpolation produces smoother results by computing weighted averages of neighboring pixels.
The scaling factor must be a positive integer, producing an output image that is N times larger in each dimension. This tool is a simplified interface to pamscale's interpolation mode. Part of the Netpbm toolkit; superseded by pamscale.

N

Scaling factor (integer multiplier).

Input PNM file.

Only integer scale factors. Part of Netpbm suite.

pnminterp was created as part of Netpbm for image interpolation.

pamscale(1), pnmscale(1), pamenlarge(1)