Patent Document ID: 9635271
Application ID: 13298615
Patent Status: 1

Claim One:
1. A method of distinguishing between daytime lighting conditions and nighttime lighting conditions based on a captured image by a vision-based imaging device along a path of travel, the method comprising: capturing an image by a vision-based imaging device; selecting a region of interest in the captured image; determining a light intensity value for each pixel within the region of interest; generating a cumulative histogram based on light intensity values within the region of interest, the cumulative histogram including a plurality of category bins representing the light intensity values, each category bin identifying an aggregate value of light intensity values assigned to each respective category bin; comparing an aggregate value within a predetermined category bin of the plurality of category bins to a first predetermined threshold; and determining whether the image is captured during the daytime lighting conditions as a function of the aggregate value within the predetermined category bin, wherein determining whether the image is captured during the daytime lighting conditions is based on the aggregate value being less than a first predetermined threshold, and wherein determining whether the captured image is obtained during the daytime lighting conditions includes determining whether the captured image includes a daylight blocking structure over the path of travel.