Calculating time to go and size of an object based on scale correlation between images from an electro optical sensor

A method for calculating a Time To Go, TTG, value between a vehicle and an intruding object, said method comprising:

• retrieving a first image of said intruding object at a first point of time, T0, and a second image of said intruding object at a second point of time, T1;
• selecting a scaling factor Si and scaling said second image with said scale factor, Si;
• resampling said scaled image to a set position XFRAC, YFRAC resulting in a resampled scaled image, RSiI;
• calculating correlation values, CXpIX, YPIX, i, between said first image and said resampled scaled image, RSiI, for different horizontal displacements XPIX and/or different vertical displacements YPIX for said resampled scaled image RSiI;
• finding a maximum correlation value Ci based on said correlation values, CXPIX, YPIX i;
• repeating the selecting the scaling factor, wherein i=i+1, the resampling, calculating the correlation values, and finding the maximum correlation values a second predetermined number of times;
• finding a largest maximum correlation value, CMAX, among said maximum correlation values, Ci, and the scale factor Si, MAX associated with the largest maximum correlation value CMAX;
• and
• calculating the Time To Go, TTG, based on said scale factor Si, MAX associated with the largest maximum correlation value CMAX.

A computer program product for use in a vehicle for calculating a Time To Go, TTG, between said vehicle and an intruding object, the computer program product comprising:

• a non-transitory computer readable medium;
• and
• computer readable code recorded on the non-transitory computer readable medium, which, when run in a processor of the vehicle causes the processor to perform a method comprising
• retrieving a first image of said intruding object at a first point of time, T0, and a second image of said intruding object at a second point of time, T1,
• selecting a scaling factor Si and scaling said second image with said scale factor, Si,
• resampling said scaled image to a set position XFRAC, YFRAC resulting in a resampled scaled image, RSiI;
• calculating correlation values, CXPIX, YPIX, i, between said first image and said resampled scaled image, RSiI, for different horizontal displacements XPIX and/or different vertical displacements YPIX for said resampled scaled image RSiI,
• finding a maximum correlation value Ci based on said correlation values, CXPIX, YPIX i,
• repeating selecting the scaling factor, wherein i=i+1, the resampling, calculating the correlation values, and finding the maximum correlation a second predetermined number of times,
• finding a largest maximum correlation value, CMAX, among said maximum correlation values, Ci,and the scale factor Si, MAX associated with the largest maximum correlation value CMAX, and
• calculating the Time To Go, TTG, based on said scale factor Si, MAX associated with the largest maximum correlation value CMAX.

A system for calculating a Time To Go, TTG, value between a vehicle and an intruding object, said system comprising:

• a memory module comprising a computer program product comprising
• computer readable code recorded on the memory module, which, when run in a processor of the vehicle causes the processor to perform a method comprising
• retrieving a first image of said intruding object at a first point of time, T0, and a second image of said intruding object at a second point of time, T1,
• selecting a scaling factor Si and scaling said second image with said scale factor, Si,
• resampling said scaled image to a set position XFRAC, YFRAC resulting in a resampled scaled image, RSiI;
• calculating correlation values, CXPIX, YPIX, i, between said first image and said resampled scaled image, RSiI, for different horizontal displacements XPIX and/or different vertical displacements YPIX for said resampled scaled image RSiI,
• finding a maximum correlation value Ci based on said correlation values, CXPIX, YPIX i,
• repeating selecting the scaling factor, wherein i=i+1, the resampling, calculating the correlation values, and finding the maximum correlation a second predetermined number of times,
• finding a largest maximum correlation value, CMAX, among said maximum correlation values, Ci, and the scale factor Si, MAX associated with the largest maximum correlation value CMAX, and
• calculating the Time To Go, TTG, based on said scale factor Si, MAX associated with the largest maximum correlation value CMAX;
• and
• a processor configured to run said computer program product.