How should the verifier project a beam onto the barcode to meet the ISO 15426-1 specification?
The standards set out a reference optical arrangement, consisting of a source of flood incident light at 45 to the surface and a collector (through an aperture) of the diffusely reflected component of this light, at right angles to the surface. For consistent reliable measurements this distance must be constant. The vertical plane in which the light source is located is parallel with the height of the bars. This set-up is intended to minimise the effect of specular (mirror-like) reflection from glossy surfaces.
