Apparatus and method for measuring haze of sheet materials or other materials using off-axis detector

An apparatus comprising:

• at least one memory configured to store an image generated by illuminating a material with first light along an optical path, the image comprising an image of second light transmitted through the material captured by a first detector, a first portion of the second light following the optical path of the first light and a second portion of the second light diverging from the optical path;
• at least one interface configured to receive one or more measurements of third light captured by a second detector that is spaced apart from the first detector, the third light diverging from the optical path by a larger amount than the second portion of the second light;
• and
• at least one processor configured to determine one or more haze values associated with the material based on the image and the one or more measurements.

A system comprising:

• a light source configured to illuminate a material with first light along an optical path;
• a first detector configured to capture an image of second light transmitted through the material, a first portion of the second light following the optical path of the first light and a second portion of the second light diverging from the optical path;
• a second detector spaced apart from the first detector and configured to generate one or more measurements of third light diverging from the optical path by a larger amount than the second portion of the second light;
• and
• an analyzer configured to determine one or more haze values associated with the material based on the image and the one or more measurements.

A non-transitory computer readable medium containing computer readable program code that, when executed by one or more processors, causes the one or more processors to:

• obtain an image generated by illuminating a material with first light along an optical path, the image comprising an image of second light transmitted through the material captured by a first detector, a first portion of the second light following the optical path of the first light and a second portion of the second light diverging from the optical path;
• obtain one or more measurements of third light captured by a second detector that is spaced apart from the first detector, the third light diverging from the optical path by a larger amount than the second portion of the second light;
• and
• determine one or more haze values associated with the material based on the image and the one or more measurements.