An apparatus for processing an image property map, the apparatus comprising: a receiver for receiving a light intensity image, a confidence map, and an image property map, the light intensity image comprising light intensity values for pixels of the light intensity image, the image property map comprising image property values for the pixels of the light intensity image and the confidence map comprising confidence values for the image property values; a filter unit arranged to filter the image property map in response to the light intensity image and the confidence map, to generate a filtered image property map, the filter unit being arranged to, for a first position in the filtered image property map: determine a combined neighborhood image property value in response to a weighted combination of neighborhood image property values being image property values in a neighborhood around the first position, a weight for a first neighborhood image property value at a second position being dependent on a confidence value for the first neighborhood image property value and a difference between a light intensity value for the first position and a light intensity value for the second position; and determine the first filtered image property value for the first position as a combination of a first image property value at the first position in the image property map and the combined neighbor image property value; wherein the filter unit is arranged to determine the weight for the first neighborhood image property value in response to a difference measure for the confidence value for the first neighborhood image property value and a confidence value for the first image property value, the determination of the weight being asymmetric with respect to the confidence value for the first neighborhood image property value and the confidence value for the first image property value with the weight depending on the sign of the difference measure. a receiver for receiving a light intensity image, a confidence map, and an image property map, the light intensity image comprising light intensity values for pixels of the light intensity image, the image property map comprising image property values for the pixels of the light intensity image and the confidence map comprising confidence values for the image property values; a filter unit arranged to filter the image property map in response to the light intensity image and the confidence map, to generate a filtered image property map, the filter unit being arranged to, for a first position in the filtered image property map: determine a combined neighborhood image property value in response to a weighted combination of neighborhood image property values being image property values in a neighborhood around the first position, a weight for a first neighborhood image property value at a second position being dependent on a confidence value for the first neighborhood image property value and a difference between a light intensity value for the first position and a light intensity value for the second position; and determine the first filtered image property value for the first position as a combination of a first image property value at the first position in the image property map and the combined neighbor image property value;