  The nearby spiral galaxy NGC 6946 was observed with ISO-CAM in the
mid-infrared, achieving 7 arcsec resolution and sub-MJy/steradian sensitivity.
Images taken with CAM filters LW2 (7 microns) and LW3 (15 microns) are analysed
to determine the morphology of this galaxy and understand better the emission
mechanisms. The mid-infrared emission follows an exponential disk with a scale
length 75 arcsec. This is 60% of the scale length in the optical R-band and
radio continuum. The nuclear starburst region is too bright for reliable
measurement in these images. Its surface brightness exceeds the inner disk by
at least a factor of 12. The arms and interarm regions are clearly detected,
with each of these components contributing about equally to the disk emission.
The arm-interarm contrast is 2-4 in the mid-IR, close to that measured in the
visible R band light and lower than the contrast in $H\alpha$, suggesting that
non-ionizing radiation contributes significantly to dust heating.
