The application relates to the technical field of precision measurement, and discloses a high-precision
image measurement method and
system based on dynamic bottom
light control, which comprises the following steps: acquiring the rough position of the edge of a measured workpiece in a
camera image, combining the physical coordinates read by a
grating ruler, and calculating the actual position of the edge in a measurement coordinate
system; mapping the actual position to a pixel coordinate
system of an LCD bottom light to generate a dynamic illumination area covering the neighborhood of the edge, and setting the remaining area as an extinguished state; sending the parameters of the dynamic illumination area to a
light source control board, generating corresponding
HDMI video timing signals by the
light source control board to drive the LCD bottom light to display a specific pattern, and synchronously outputting a camera trigger
signal; the LCD bottom light only emits light in the dynamic illumination area, the emitted diffuse light passes through a loading platform to irradiate the real geometric edge of the measured workpiece, a camera receives the
transmitted light and collects a contour image; performing sub-pixel
edge extraction on the contour image, calculating the size of the workpiece, and realizing high-precision
image measurement at a sub-micron level.