the size of the keyboard approximately 7mmx3mm the field of view is set at 7mmx3mm
assumed working distance wd = 75mm, the lens focal length f = 51mm, 50mm lens optional, if you want to adjust the working distance, you can choose other focal length of the lens
page detection tasks require selection sick ivc-2dm industrial smart camera, the physical resolution of 640x480, system resolution 7mm / 640pix = 0.01 mm / pix, the applications use high-brightness backlight source, sub-pixel algorithms can be stabilized at 0.1 -0.05 pixels, calculated at 0.1, the system resolution the 7mm / 640pix * 0.1 = 0.001 mm / pix, the camera repeat accuracy of about 0.002-0.003mm
according to the above configuration, the 100 static test found the system static repeatability 0.001 mm, is stable at 0.05 pixel sub-pixel algorithms.
the experiment did not do an accurate calibration, so the diameter of the experimental results do not necessarily reflect the true value, but it reflects the true repeat accuracy of the system.
the measured actual number of holes 319, each time the results can not all display a page randomly selected three holes to do the show.
although the experimental use only 30-megapixel camera, but the image effect is very good, visible anomalies in the holes
due to the the camera integrated structure product dimensions are slightly larger, but all the data are in a shielded housing good performance, image information is directly into the processor, greatly improved the stability of the image data, good way to ensure a repeat accuracy of the system, and can be seen by the experimental results.
the camera overall protection class of ip65 (dust and splashing water), is a real industrial camera.