Method and device for processing lightfield data
Method and device adapted for the processing of lightfield data representative of a scene, said lightfield data comprising a plurality of elements, 4-dimensional coordinates being associated with each element. Following operations are performed: associating a ray with each element, the ray being obtained from the 4-dimensional coordinates associated with each element; determining a depth information for each element; determining an origin of each ray in the scene according to the depth information; grouping rays having a same origin in the scene to form a plurality of groups; processing the lightfield data according to the plurality of groups.
1. A method of processing lightfield data representative of a scene, said lightfield data comprising a plurality of elements, 4-dimensional coordinates being associated with each element of said plurality of elements, the method comprising:
associating a ray with each element, said ray being obtained from the 4-dimensional coordinates associated with each said element;
determining a depth information for each said element;
determining an origin of each said ray in the scene according to said depth information;
grouping rays with a same origin in the scene to form a plurality of groups;
for at least one pair of groups of said plurality of groups, establishing a relationship between a first group of rays and a second group of rays forming said at least one pair, a weight being associated with said relationship and determined by:
for each ray of at least a part of the rays of said first group, calculating a difference between a ray of said second group and said ray of said first group, when said ray of said second group is comprised in a neighborhood of said ray of said first group;
determining said weight by summing said differences;
processing said lightfield data according to said plurality of groups and said relationship.
2. The method according to claim 1 , wherein a first ray referenced ‘i’ and represented with 4-dimensional coordinates (s i , t i , x i , y i ) and a second ray referenced ‘i’ and represented with 4-dimensional coordinates (s j , t j , x j , y j ) are grouped in a same group of said plurality of groups when:
x i +( s i −s j )× D ( s i ,t i ,x i ,y i )− x j <E 1, and
y i +( t i −t j )× D ( s i ,t i ,x i ,y i )− y j <E 2
wherein D(s i , t i , x i , y i ) corresponds to the depth information associated with said first ray, E1 corresponds to a first determined value and E2 corresponds to a second determined value.
3. The method according to claim 2 , wherein said first ray and said second ray are grouped in said same group when following conditions are further met:
x j +( s j −s i )× D ( s j ,t j ,x j ,y j )− x i <E 1, and
y j +( t j −t i )× D ( s j ,t j ,x j ,y j )− y i <E 2
wherein D(s j , t j , x j , y j ) corresponds to the depth information associated with said second ray.
4. The method according to claim 1 , wherein at least one ray is not assigned to a group of said plurality of groups.
5. The method according to claim 1 , wherein the processing comprising segmenting said lightfield data according to said relationship.
6. A non-transitory processor readable medium having stored therein instructions for causing a processor to perform the operations of the method according to claim 1 .
7. A device adapted to process lightfield data representative of a scene, said lightfield data comprising a plurality of elements, 4-dimensional coordinates being associated with each element of said plurality of elements, wherein the device comprises at least one processor configured to:
associate a ray with each element, said ray being obtained from the 4-dimensional coordinates associated with said each element;
determine a depth information for said each element;
determine an origin of each said ray in the scene according to said depth information;
group rays with a same origin in the scene so as to form a plurality of groups;
for at least one pair of groups of said plurality of groups, establish a relationship between a first group of rays and a second group of rays forming said at least one pair, a weight being associated with said relationship and determined by:
for each ray of at least a part of the rays of said first group, calculating a difference between a ray of said second group and said ray of said first group, when said ray of said second group is comprised in a neighborhood of said ray of said first group;
determining said weight by summing said differences;
process said lightfield data according to said plurality of groups and said relationship.
8. The device according to claim 7 , wherein said at least one processor is configured to group a first ray referenced ‘i’ and represented with 4-dimensional coordinates (s i , t i , x i , y i ) and a second ray referenced ‘j’ and represented with 4-dimensional coordinates (s j , t j , x j , y j ) in a same group of said plurality of groups when:
x i +( s i −s j )× D ( s i ,t i ,x i ,y i )− x j <E 1, and
y i +( t i −t j )× D ( s i ,t i ,x i ,y i )− y j <E 2
wherein D(s i , t i , x i , y i ) corresponds to the depth information associated with said first ray, E1 corresponds to a first determined value and E2 corresponds to a second determined value.
9. The device according to claim 8 , wherein said at least one processor is configured to group said first ray and said second ray in said same group when following conditions are further met:
x j +( s j −s i )× D ( s j ,t j ,x j ,y j )− x i <E 1, and
y j +( t j −t i )× D ( s j ,t j ,x j ,y j )− y i <E 1
wherein D(s j , t j , x j , y j ) corresponds to the depth information associated with said second ray.
10. The device according to claim 7 , wherein at least one ray is not assigned to a group of said plurality of groups.
11. The device according to claim 7 , wherein the at least one processor is further configured to segment said lightfield data according to said relationship.
12. A multimedia terminal comprising a lightfield acquisition device and the device according to claim 7 .