A 2MP or 4K label does not show plate detail on its own; field of view, capture distance and software requirements determine the camera choice.
A 2MP camera may suit a lane, but the megapixel label cannot settle the question. The useful measure is how many pixels represent the smallest relevant plate at the widest and furthest intended capture positions.
That detail must meet the recognition software's documented requirements. A clear sample from the centre of an empty lane does not establish coverage of the whole capture area.
Manufacturer discussion of plate pixel density
Digital plate capture turned optical detail into pixels that recognition software could analyse. Higher-resolution network cameras made wider views possible, but the available pixels still had to be distributed across that road space.
Increasing scene width with the same horizontal resolution reduces the detail assigned to each plate. This physical relationship remains relevant whether the camera is described as 2 MP or 4K.
Higher resolution is useful when the geometry and software requirements justify it. Multiple narrower views may be an alternative to one wide camera, especially where several lanes need separate assessment.
The recogniser must support the selected image size as well. Buying a 4K camera leaves that compatibility question open and does not remove the need to assess placement, distance and lighting.
Take an illustrative 0.52 m plate square to the view. In a 1,920-pixel-wide image covering 4 m at the plate plane, it spans about 250 pixels. If the same image covers 8 m, the plate spans about 125 pixels. These are image-scale examples, not acceptance limits.
Angled plates, smaller formats and greater distances change the result. Measure the smallest expected plate throughout the intended area and test each lane independently. Record any excluded positions or vehicle groups rather than allowing a central sample to stand for every passage.
RackLink ties supported streams to placement, resolution, frame rate and lighting. Compatibility therefore needs to be assessed with the actual camera view and operating conditions.
A megapixel label alone cannot describe those factors. The deployment assessment connects the supplied stream to the plate detail needed in that particular lane.
Aero Ranger: supported local stream processing with RackLink
Sources were reviewed on the publication date. Check the linked material for current details.
