What is correspondence between DMC size and reader distance?
In this post I will present how is reading distance correlated with DMC module size. For test object I used industrial reader from company IFM efector. Logical is that there is a direct link existing between DMC size and reading distance -> with increasing distance we need bigger codes.
As already described in other posts there are more readability factors as illumination, angle, contrast, quality of DMC code. In following test we focused on perpendicular reading of code with changing the read distance as show on picture below.
As shown in graph below there is almost an linear correspondence between DMC size and reading distance. To read DMC with module size down to 0,15 we must place DMC scanner very close. To read DMC from 400 mm we must already use codes with module size over 1,2 mm.
There is quite some variation in performance of industrial DMC scanners so it makes sense to read the technical specification before purchase. Readers differ in focal length, view angle… The reader with specifications as described in graph above comes in range 400$-600$.
In next post I will perform a test with iphone 4S and iphone 6 and present results about correlation between DMC size and reader distance.