Imaging-based non-contact gloss measurement device and method

An imaging-based non-contact gloss measurement device, comprising:

• a housing, a top cover of which is provided with a measurement window, a measurement zone being located above the measurement window;
• an illumination light source which is mounted inside the housing and on one side of the measurement window and is configured to illuminate the measurement zone at an incident angle θ1;
• and
• a grayscale camera which is mounted inside the housing and on another side of the measurement window and is configured to receive light reflected from the measurement zone at a reflection angle θ2 for grayscale imaging, measuring grayscale values, and obtaining gloss values from the grayscale values;
• wherein
• an optical axis of the illumination light source and an optical axis of the grayscale camera intersect at a center of the measurement zone, and the optical axis of the illumination light source and the optical axis of the grayscale camera together form a measurement plane;
• relative to the center of the measurement zone, the illumination light source has an incident divergence angle
• α
• 1
• ′
• in the measurement plane and an incident divergence angle
• β
• 1
• ′
• perpendicular to the measurement plane;
• relative to the center of the measurement zone, the grayscale camera has a reflection divergence angle
• α
• 2
• ′
• in the measurement plane and a reflection divergence angle
• β
• 2
• ′
• perpendicular to the measurement plane, where θ1=θ2,
• α
• 1
• ′
• >
• α
• 2
• ′
• ,
• and
• ⁢
• β
• 1
• ′
• >
• β
• 2
• ′
• .