1. A traffic sign detection system for a vehicle, comprising: at least one processing device programmed to: receive at least one image of an environment including a traffic sign ahead of the vehicle; sample the at least one image to generate a plurality of images having different sizes; convolve the plurality of images with a template image to generate a plurality of convolved images; compare one or more pixel values of the convolved images to a predetermined threshold; and select pixel values within local regions of the convolved images as attention candidates based on the comparison to the predetermined threshold.