CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2020-0091173, filed on Jul. 22, 2020, in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments of the disclosure relate to a device and method for detecting fog on the road.

DESCRIPTION OF RELATED ART

In Korea, large-scale traffic accidents are repeatedly occurring due to bad weather such as fog, snow, rain, and wind, and socio-economic damage due to loss of life is increasing. In particular, fog interferes with the driver's vision and causes it difficult for the driver to secure a safe distance, resulting in a higher chance of serious traffic accidents.

When the traffic capability and stability of the road decrease due to bad weather such as fog, snow, rain, wind, etc., the meteorological agency detects fog using a visibility system, but visibility systems are installed in limited sites due to high costs.

Accordingly, a number of methods for fog detection using images are currently being conducted, which include a method of detecting fog by extracting several fog features from an input image and measuring the similarity with the learning data or a method for detecting fog by calculating the visual range (or visibility) using the vehicle highlights.

Korean Patent Nos. 10-1880850, issued on Jul. 20, 2018, 10-1364727, issued on Feb. 20, 2014, and 10-1949968, issued on Feb. 21, 2019 disclose a configuration for detecting fog using temporal filtering and a correlation between saturation and brightness in a road driving image by setting a region within a predetermined distance or more from a vanishing point, as a region of interest, and calculating a ratio of saturation channel to brightness channel for the region of interest to thereby obtain the feature of detecting fog and applying temporal filtering using information about the saturation channel-brightness channel ratio of adjacent frames, a configuration including detecting a valid region needed to be analyzed to detect fog in an image, performing fog detection analysis on each of daytime fog detection and nighttime fog detection using a reference depth map and an image correction matrix, calculating a visual range according to the result, and determining the foggy condition, and a configuration in which the amount of transmission is corrected using a dark channel algorithm and a guided filter and a fog contour line is determined.

However, fog forecasting is useless if real-time detection of a situation where it is foggy or clear is impossible. The above-described configurations use a large amount of network and computing resources to detect fog from an image and thus suffer from slow processing and even inaccuracy, resultantly failing to meet immediacy and presentness.

Further, it is expensive to establish an infrastructure for such configurations because the configurations need to use depth cameras, not common CCTV-based surveillance cameras.

Therefore, a need exists for a device and method for quickly and accurately detecting fog to prevent social and economic damage caused by fog generated on the road.

SUMMARY

According to various embodiments, there may be provided a road fog detection device and method that may quickly and precisely detect fog to prevent social, economical damage due to fog on the road, provide substantially the same effects as a depth camera does, using a common CCTV camera, by converting fixed objects into coordinates, per visual range, identify the region pattern of the fog in an image, and quickly and accurately output the visual range.

However, the objects of the embodiments are not limited thereto, and other objects may also be present.

According to an embodiment, a device for detecting fog on a road comprises an imaging device installed to capture a two-way road and capturing a fog on the two-way road, a network configuring device provided under the imaging device and transmitting an image captured by the imaging device, a fog monitoring device receiving the image from the network configuring device, analyzing the image to thereby detect the fog, and outputting an alert per predetermined crisis level, and a display device displaying the alert output from the fog monitoring device and transmitting the alert via a wired or wireless network.

The imaging device may include a camera capturing the two-way road, a bracket provided under the camera and adjusting a direction thereof using a bolt and a nut, a median strip guardrail fixing base formed in a double-winged structure to be mounted on a median strip guardrail without damaging the median strip guardrail and fixed to, or removed from, the median strip guardrail using a bolt and a nut, and a supporting pole connecting the bracket with the median strip guardrail fixing base and adjusting a height thereof using at least one bolt.

The fog monitoring device may include an image receiver installed within a predetermined distance from a site where the imaging device is installed and storing the image from the camera of the imaging device and outputting the image, an image analyzer equipped with a fog detection program configured to detect the fog using the image output from the image receiver, receiving image settings for the site where the imaging device is installed, a fog detection condition, and an crisis level determination condition, and outputting a detection result corresponding to the received image settings, the fog detection condition, and the crisis level determination condition, and a result display displaying information resultant from detecting and analyzing the fog by the image analyzer and transmitting the displayed information via the wired or wireless network.

The image settings may be intended to set at least one element value for distance calculation according to an installation environment of the camera of the imaging device. The fog detection condition and the crisis level determination condition may correspond to system settings.

According to an embodiment, a fog alerting method performed by a fog alerting device comprises receiving an image transmitted from an imaging device capturing a two-way road and calculating a distance to a site where a fog occurs, determining a contour of the fog from the image and then recognizing the fog by determining a region of the fog from the determined contour, and calculating a distance between a position of the imaging device and a visible point recognized in the image and, when the distance between the position of the imaging device and the visible point corresponds to a distance per predetermined level, outputting an alert corresponding to the distance per predetermined level.

Receiving the image transmitted from the imaging device capturing the two-way road and calculating the distance to the site where the fog occurs may include converting a road image in the image into a two-dimension (2D) plane with coordinates, establishing image settings for setting at least one element value for distance calculation to calculate the distance to the site where the fog occurs, from the image, calculating the distance to the site where the fog occurs, using the at least one element value for distance calculation and an equation represented as:

R=n⁢{Dmax⁡(Ymax-Y)e+Dmax⁢Ymax}-f-n+s×H×LsetLstd×ev

Here, R denotes the distance to the site where the fog occurs, n denotes a correction constant for near distance, Dmax denotes a maximum distance, Ymax denotes maximum coordinates, Y denotes fog recognition coordinates, e denotes a correction constant for effective distance, f denotes a correction constant for far distance, s denotes a correction constant for shortest distance, H denotes a height or altitude, Lset denotes a lens setting focal length, Lstd denotes a lens standard focal length, and v denotes a correction constant for vertical angle.

Determining the contour of the fog from the image and then recognizing the fog by determining the region of the fog from the determined contour may include setting a strength of extraction of the contour of the fog and selecting a lower end of a vertical contour by selecting and separating a horizontal contour among a plurality of contours, when an original color of the selected lower end of the vertical contour is a chromatic color, excluding the vertical contour, and determining that a contour in a predetermined analysis target space is the contour of the fog. The contour of the fog may be determined using a Sobel edge detector.

Determining the contour of the fog from the image and then recognizing the fog by determining the region of the fog from the determined contour may include when the region of the fog is determined, extracting a contour of a predetermined analysis target space from the contour of the fog, determining a red-green-blue (RGB) value of a color coordinate system from the contour of the predetermined analysis target space, determining a fog feature value based on the RGB value, when an RGB value of a coordinate neighboring any one coordinate in the contour of the predetermined analysis target space is smaller than the fog feature value, selecting the any one coordinate, and recognizing the fog by displaying the selected any one coordinate on a space. Recognition analysis of the fog may be performed by pattern recognition analysis including a flood fill scheme.

Calculating the distance between the position of the imaging device and the visible point recognized in the image and, when the distance between the position of the imaging device and the visible point corresponds to the distance per predetermined level, outputting the alert corresponding to the distance per predetermined level may include, when the distance to the visible point is less than 1 km, estimating the occurrence of the fog and outputting an alert corresponding to a distance for each of low, moderate, high, and extreme levels as the distance to the visible point reduces.

The alert corresponding to the distance for each level may indicate a normal level when the distance to the visible point is 1 km or more, the low level when the distance to the visible point is less than 1 km, the moderate level when the distance to the visible point is less than 250 m, the high level when the distance to the visible point is less than 100 m, and the extreme level when the distance to the visible point is less than 50 m.

According to various embodiments of the disclosure, the road fog detection device and method may quickly and precisely detect fog to prevent social, economical damage due to fog on the road, provide substantially the same effects as a depth camera does, using a common CCTV camera, by converting fixed objects into coordinates, per visual range, identify the region pattern of the fog in an image, and quickly and accurately output the visual range.

