Image resolution adjustment method
There is disclosed an image resolution adjustment method comprising the steps of: performing a predetermined selection rule to select one of scaling modes based on a source resolution Vi and a display resolution Vo to generate a scaling value set for outputting a scaled image; and determining whether a smoothing process to determine whether or not the scaled image is smoothed based on application requirements, wherein the scaling modes comprises a first scaling mode, a second scaling mode and a third scaling mode to generate each of the corresponding scaling value set, respectively. The scaling value set is provided to generate replicated pixels or lines for each pixel or line of the source image during a horizontal or vertical scaling period, and the replicated pixels or lines are arranged in horizontal or vertical symmetry in relation to its central region of the source image.
1. An image resolution adjustment method, for receiving a source resolution Vi from a source image and a display resolution Vo, comprising the steps of:
performing a predetermined selection rule in a scaling phase to generate a scaling value set based on said source resolution Vi and said display resolution Vo for outputting a scaled image; and
determining whether or not said scaled image is smoothed based on a variety of application requirements of display in a smoothing phase;
wherein said predetermined selection rule comprises:
a first decision to determine whether or not a first scaling mode is selected based on said source resolution Vi and said display resolution Vo;
a second decision to determine whether or not a second scaling mode is selected based on said source resolution Vi and said display resolution Vo; and
a third decision to determine whether or not a third scaling mode is selected based on said source resolution Vi and said display resolution Vo;
wherein said first decision is set to TRUE if both conditions below are satisfied
( Vo−Vi )<=(2* Vi ),
and
( Vo/Vi )= n , where n is not an integer;
wherein said second decision is set to TRUE if three conditions below are satisfied
( Vo−Vi )>(2* Vi ),
( Vo/Vi )= n , where n is not an integer, and
(7* Vi )>(2* Vo );
and wherein said third decision is set to TRUE if three conditions below are satisfied
( Vo−Vi )>(2* Vi ),
( Vo/Vi )= n , where n is not an integer, and
(7* Vi )<=(2* Vo ).
2. An image resolution adjustment method according to claim 1 , wherein said scaling value set includes a center resolution Vc, a sided resolution Vs and scaling factors corresponding to said center resolution Vc and said sided resolution Vs determined by the equations below in said scaling phase when said first decision is TRUE:
Vc =( Vo−Vi )/2,
and
Vs =(3* Vi−Vo )/4,
where Vc and Vs are integers, respectively, and
said scaling factors are equal to 1 and 3.
3. An image resolution adjustment method according to claim 2 , wherein said sided resolution value Vs is selected from an upper sided resolution value Vs-up or a lower sided resolution value Vs-dn when Vs is not an integer, and wherein
Vs-up is determined by the equation in said the smoothing phase:
Vs - up =(3* Vi−Vo )/4−0.5, and
Vs-dn is determined by the equation:
Vs - dn =(3* Vi−Vo )/4+0.5.
4. An image resolution adjustment method according to claim 1 , wherein said scaling value set includes a center resolution Vc, a sided resolution Vs and scaling factors corresponding to said center resolution Vc and said sided resolution Vs determined by the equations below when said second decision is TRUE:
Vs =( Vo− 3 *Vi )/2,
Vc=Vi− 2* Vs=x+y ,
and
2 *x+z*y=Vo− 2* Vs,
where x, y>0 and z=3, 4, 5, . . . , respectively, and
said scaling factors are equal to 1, 2, 3 or an integer greater than 3.
5. An image resolution adjustment method according to claim 1 , wherein said scaling value set includes a center resolution Vc, a sided resolution Vs and scaling factors corresponding to said center resolution Vc and said sided resolution Vs determined by the equations below when said third decision is TRUE:
Vs=Vi/ 4,
where Vs is an integer multiple, and
said center resolution Vc is determined by the two equations:
Vc=Vi− 2* Vs=x+y ,
and
2 *x+z*y=Vo−Vi
where x, y>0 and z=3, 4, 5, . . . , respectively, and
said scaling factors are equal to 2, 3 or an integer greater than 3.
6. An image resolution adjustment method according to claim 5 , wherein said sided resolution Vs is selected from an upper sided resolution Vs-up or a lower sided resolution value Vs-dn when Vs is not an integer, wherein
Vs-up is determined by the equation:
Vs - up=Vi/ 4−0.5 and
Vs —DN is determined by the equation:
Vs - dn=Vi/ 4+0.5.
7. An image resolution adjustment method according to claim 1 , wherein said predetermined selection rule further comprises a fourth decision to determine whether or not a fourth scaling mode is selected based on said source resolution Vi and said display resolution Vo.
8. An image resolution adjustment method according to claim 7 , wherein said fourth scaling mode is set to TRUE if a condition below is satisfied
( Vo/Vi )= n , when n is an integer multiple, and
said scaling value set including a scaling factor equal to n.
9. An image resolution adjustment method according to claim 1 , wherein said scaling value set is provided to generate replicated pixels for each pixel of said source image during a horizontal scaling period, and said replicated pixels are arranged in an axial symmetry in relation to its central region of said source image.
10. An image resolution adjustment method according to claim 1 , wherein said scaling value set is provided to generate replicated lines for each line of said source image during a vertical scaling period, and said replicated lines are arranged in an axial symmetry in relation to its central region of said source image.