An image sensor, comprising: a matrix of rows and columns of photosensitive pixels (106, 107), wherein the matrix comprises a plurality of stitching blocks that are adjacently arranged in the column direction of the matrix; wherein each stitching block comprises: a plurality of first pixels and a plurality of second pixels; a plurality of dose select lines (114, 115) configured for carrying respective dose select signals; and a pixel select controller configured for: in an image read-out mode of the image sensor, simultaneously selecting first pixels and second pixels, in a given row and given stitching block, one row at a time; in a dose sensing mode of the image sensor, simultaneously selecting second pixels in different rows and different stitching blocks in dependence of the dose select signals; the image sensor further comprising, at each connecting interface between stitching blocks that are adjacently arranged in the column direction, a dose select line connecting unit for connecting each dose select line (114, 115) of a first stitching block among the adjacent stitching blocks to a respective dose select line of a second stitching block among the adjacent stitching blocks to prevent multiple second pixels in the same column of the matrix from being selected. a matrix of rows and columns of photosensitive pixels (106, 107), wherein the matrix comprises a plurality of stitching blocks that are adjacently arranged in the column direction of the matrix; wherein each stitching block comprises: a plurality of first pixels and a plurality of second pixels; a plurality of dose select lines (114, 115) configured for carrying respective dose select signals; and a pixel select controller configured for: in an image read-out mode of the image sensor, simultaneously selecting first pixels and second pixels, in a given row and given stitching block, one row at a time; in a dose sensing mode of the image sensor, simultaneously selecting second pixels in different rows and different stitching blocks in dependence of the dose select signals; a plurality of first pixels and a plurality of second pixels; a plurality of dose select lines (114, 115) configured for carrying respective dose select signals; and a pixel select controller configured for: in an image read-out mode of the image sensor, simultaneously selecting first pixels and second pixels, in a given row and given stitching block, one row at a time; in a dose sensing mode of the image sensor, simultaneously selecting second pixels in different rows and different stitching blocks in dependence of the dose select signals; in an image read-out mode of the image sensor, simultaneously selecting first pixels and second pixels, in a given row and given stitching block, one row at a time; in a dose sensing mode of the image sensor, simultaneously selecting second pixels in different rows and different stitching blocks in dependence of the dose select signals; the image sensor further comprising, at each connecting interface between stitching blocks that are adjacently arranged in the column direction, a dose select line connecting unit for connecting each dose select line (114, 115) of a first stitching block among the adjacent stitching blocks to a respective dose select line of a second stitching block among the adjacent stitching blocks to prevent multiple second pixels in the same column of the matrix from being selected.