Quantum　image　processing　is　the　intersection　of　quantum　computation　and　image　processing.　Due　to　it　is　a　newly　emerging　thing,　researchers　are　facing　not　only　great　opportunities　but　also　many　challenges　to　develop　more　efficient　and　practicable　services.　We　provide　a　comprehensive　survey　on　quantum　image　processing　to　gather　the　current　mainstream　and　discuss　the　advances　made　in　the　area,　including　quantum　image　representations,　processing　algorithms,　and　image　measurement.　Moreover,　some　open　challenges　and　future　directions　are　pointed　out　to　attract　continued　research　efforts.