Bar Code Scan Lenses
Bar code scanning is a very common, but tricky application of both imaging and illumination. Generally, the distance from bar code to camera is highly variable since either the bar code or the camera position is hand-held. This requires a depth of field that impacts both the lens and the illumination, for depth of field is highly dependent on lens F-number as well as aberration content. As codes become lower in contrast, or necessarily become smaller, motion blur becomes a significant challenge. In many cases, some of these challenges can be offset by excellent illumination design that provides oblique, non-specular lighting of high illuminance such that the integration time of the camera can become short enough to limit the motion blur.
SMA has had experience in designing multiple 1D and 2D bar code scanning systems. We have worked with the algorithm developers, providing them simulated images incorporating defocus in order to enable them to improve the robustness of the algorithms in the presence of reduced contrast and sharpness prior to finalization of the lens and illumination design.
This system-oriented approach is characteristic of the manner in which we prefer to work with our clients. Unless the optics, electronics, software, and mechanical elements all function properly in combination by design, the end result will generally require costly iterations during prototyping and early production.