A machine-vision-based counter includes an image acquisition component (imager), wherein light provides discrimination between a background field and imageable units located away from the imager. The imager outputs data representing the field and units; an image processor receiving imager data finds countable units therein. An operator interface accepts command inputs and presents count output. A controller manages image acquisition, processor, and operator interface functions. A counting method includes configuring an imager to detect light, directing light from a source to units positioned to be detected by the imager, and directing the light to the imager. The method includes discriminating between a background field and imageable units; providing, as an imager output, data representing the field and units; configuring an image-processor to receive imager data; configuring the processor to interpret the data as counted units on a background field; and configuring an operator interface to present a count result.