DETECTING DEVICE FOR ROAD MONITORING

A detecting device for road monitoring which detects traveling states of vehicles on a road (traffic stagnation, stopping of vehicles, etc.) or fallen objects on a road is provided. Luminance change detecting unit prepares background image data by taking a time average of luminance for each picture element, and detects image portions where inputted image data is different in luminance from the prepared background image data. Hue change detecting unit prepares background image data by taking a time average of hue for each picture element, and detects image portions where inputted image data is different in hue from the prepared background image data. Overlapping portion extracting and judging unit extracts overlapping portions between image portions detected by the luminance change detecting unit when it is in the daytime and illuminance is larger than a predetermined value and image portions detected by the hue change detecting unit at the same point of time, and judges the extracted overlapping portions to represent objects to be detected. Comprehensive portion extracting and judging unit extracts comprehensive portions covering image portions detected by the luminance change detecting unit when it is in the daytime and illuminance is smaller than a predetermined value and image portions detected by the hue change detecting unit at the same point of time, and judges the extracted comprehensive portions to represent objects to be detected.