Method for determination of a region of interest in an image comprising the following steps: - a plurality of lines L i i=1,.., n formed by pixels is defined in the image; - in each line L i a plurality of segments S j j=1,.., m constituted by pixels (312, 313, 314) is defined; - a level of luminance NVG(S j) of each segment S j is calculated from the luminance of the pixels which constitute this segment S j: - according to this level of luminance NVG(S j) the segment S j is selected, or this segment S j is excluded from the region of interest (315, 316, 317); - the region of interest is obtained by merging all of the segments selected for each of the lines, characterised in that the method is implemented in a road vehicle, and in that: - there is isolation in the image of a search window inside which the plurality of lines L i (600, 650) is defined; - the search window is cut vertically into a plurality of zones, and each zone is allocated specific rules concerning the definition of the segments S j and/or of the lines L i: - the search window comprises at least a first zone (41a, 41b) and a second zone (42a, 42b) which are positioned respectively horizontally around a first and a second point of interest of the image; - there is determination of at least one out of the two points of interest as being an escape point on the basis of an escape point detection system based on an angle at the steering wheel of the vehicle and/or on the basis of information obtained from a navigation system and/or on the basis of a system for detection of road marking lines; - the search window comprising a third zone (43a, 43b) defined such as to ensure continuity between the first (41a, 41b) and second (42a, 42b) zones. - a plurality of lines L i i=1,.., n formed by pixels is defined in the image; - in each line L i a plurality of segments S j j=1,.., m constituted by pixels (312, 313, 314) is defined; - a level of luminance NVG(S j) of each segment S j is calculated from the luminance of the pixels which constitute this segment S j: - according to this level of luminance NVG(S j) the segment S j is selected, or this segment S j is excluded from the region of interest (315, 316, 317); - the region of interest is obtained by merging all of the segments selected for each of the lines, - there is isolation in the image of a search window inside which the plurality of lines L i (600, 650) is defined; - the search window is cut vertically into a plurality of zones, and each zone is allocated specific rules concerning the definition of the segments S j and/or of the lines L i: - the search window comprises at least a first zone (41a, 41b) and a second zone (42a, 42b) which are positioned respectively horizontally around a first and a second point of interest of the image; - there is determination of at least one out of the two points of interest as being an escape point on the basis of an escape point detection system based on an angle at the steering wheel of the vehicle and/or on the basis of information obtained from a navigation system and/or on the basis of a system for detection of road marking lines; - the search window comprising a third zone (43a, 43b) defined such as to ensure continuity between the first (41a, 41b) and second (42a, 42b) zones.