Patent ID: 8164750

Claim:
An apparatus for detecting colored foreign particles in quartz powder material comprising: a material supplying means for continuously supplying white quartz powder material having polygonal external surfaces at a given rate; a belt conveying means for conveying the quartz powder material continuously supplied from the material supplying means; a first light emitting means located above the belt conveying means and emitting light with a given wavelength; a light diffusing means located below the first light emitting means and above the belt conveying means and converting the light emitted from the first light emitting means into scattering light to irradiate the quartz powder material conveyed on the belt conveying means; and a color imaging means located above the belt conveying means and continuously shooting color images of the quartz powder material, wherein the quartz powder material is irradiated with the scattering light from the light diffusing means to clarify shading of color images shot by the color imaging means to thereby detect colored foreign particles contained in the quartz powder material, and the apparatus further comprising a means for improving a detection precision of colored foreign particles that a monochrome image of the quartz powder material conveyed on the belt conveying means is shot with a differential interference microscope and a spatial filter is applied to the shot monochrome image to emphasize a section of changing luminance and the emphasized section is binarized to detect colored foreign particles contained in the quartz powder material.