An apparatus for determining a position of an object within a representation of an image to be represented, comprising: an input for the image to be represented; a modulation image generator for generating at least one modulation image, the at least one modulation image being subdivided into a plurality of fields and a modulation image value of a certain field representing location information of the field within the modulation image; an image modulator for modulating the image to be represented with the modulation image, a difference between the image to be represented and the image modulated with the at least one modulation image being below a threshold of perception of humans; wherein modulating the image to be represented with the modulation image is configured such that, due to a low modulation depth, the modulation remains below the threshold of perception of humans; an output for the image modulated with the at least one modulation image for being displayed on a display apparatus; an optical sensor for sensing an optical sensor emitted from an image section of the image modulated with the modulation image, and for generating a corresponding sense signal; and an evaluation unit for determining image section location information using the optical signal emitted by the image section, by the evaluation unit being configured to extract a piece of location information of at least one field located at least partly within the image section, from the optical signal emitted by the image section; wherein the location information is Gray-coded in a generalized manner relative to mutually adjacent fields. wherein the evaluation unit is configured to evaluate extracted location information which cannot be associated unambiguously to a field, by evaluating relatively unambiguous bit values of bits of the location information for limiting a spatial region within which the image section is located, and by relatively indifferent bit values of bits of the location information indicating that the image section overlaps at least two fields of the modulation image. wherein the evaluation unit is configured to obtain a weighted sum of bit values of bits of the location information to obtain bit values or bit intermediate values; wherein a respective weight of bit values of bits of the location information in the weighted sum corresponds at the image section to an area portion of a field associated with respective location information; wherein the evaluation unit is configured to perform the evaluation by means of a first and second threshold, so that a bit intermediate value below the first or above the second threshold is evaluated to be a relatively unambiguous bit value; and so that a bit intermediate value between the first and second thresholds is evaluated to be a relatively indifferent bit value. an input for the image to be represented; a modulation image generator for generating at least one modulation image, the at least one modulation image being subdivided into a plurality of fields and a modulation image value of a certain field representing location information of the field within the modulation image; an image modulator for modulating the image to be represented with the modulation image, a difference between the image to be represented and the image modulated with the at least one modulation image being below a threshold of perception of humans; wherein modulating the image to be represented with the modulation image is configured such that, due to a low modulation depth, the modulation remains below the threshold of perception of humans; an output for the image modulated with the at least one modulation image for being displayed on a display apparatus; an optical sensor for sensing an optical sensor emitted from an image section of the image modulated with the modulation image, and for generating a corresponding sense signal; and an evaluation unit for determining image section location information using the optical signal emitted by the image section, by the evaluation unit being configured to extract a piece of location information of at least one field located at least partly within the image section, from the optical signal emitted by the image section; wherein the location information is Gray-coded in a generalized manner relative to mutually adjacent fields. wherein the evaluation unit is configured to evaluate extracted location information which cannot be associated unambiguously to a field, by evaluating relatively unambiguous bit values of bits of the location information for limiting a spatial region within which the image section is located, and by relatively indifferent bit values of bits of the location information indicating that the image section overlaps at least two fields of the modulation image. wherein the evaluation unit is configured to obtain a weighted sum of bit values of bits of the location information to obtain bit values or bit intermediate values; wherein a respective weight of bit values of bits of the location information in the weighted sum corresponds at the image section to an area portion of a field associated with respective location information; wherein the evaluation unit is configured to perform the evaluation by means of a first and second threshold, so that a bit intermediate value below the first or above the second threshold is evaluated to be a relatively unambiguous bit value; and so that a bit intermediate value between the first and second thresholds is evaluated to be a relatively indifferent bit value.