Apparatus and a method for generating data representing a pixel beam
There are several types of plenoptic devices and camera arrays available on the market, and all these light field acquisition devices have their proprietary file format. However, there is no standard supporting the acquisition and transmission of multi-dimensional information. It is interesting to obtain information related to a correspondence between pixels of a sensor of said optical acquisition system and an object space of said optical acquisition system. Indeed, knowing which portion of the object space of an optical acquisition system a pixel belonging to the sensor of said optical acquisition system is sensing enables the improvement of signal processing operations. The notion of pixel beam, which represents a volume occupied by a set of rays of light in an object space of an optical system of a camera is thus introduce.
1. A computer implemented method comprising:
generating data representative of a volume, in an object space of an optical acquisition system, occupied by a set of rays of light passing through a pupil of said optical acquisition system and a conjugate of at least one pixel of a sensor of said optical acquisition system said volume occupied by said set of rays of light being called a pixel beam, and
generating a digital file comprising the data representative of said pixel beam, said data comprising:
parameters defining said pupil of the optical acquisition device,
parameters defining the smallest section of said pixel beam, called the waist, which corresponds to the conjugate, in the object space, of at least said pixel of the sensor, wherein said parameters defining the waist of said pixel beam are computed based on parameters defining said at least one pixel, and the parameters representing the waist of the pixel beam comprise a distance between the waist of the pixel beam and the center of the pupil, and an orientation of the waist of the pixel beam in a coordinate system associated to the optical acquisition system.
2. The method according to claim 1 wherein parameters representing an intensity of the light captured by said pixel obtained from light field data captured by the optical acquisition system, are associated to the parameters representative of the pixel beam in said digital file.
3. The method according to claim 2 wherein the parameters defining the pupil comprise a radius of the pupil, coordinates of the pupil center in the coordinate system associated to the optical acquisition system, and angles defining an orientation of the pupil in said coordinate system.
4. An apparatus comprising:
at least one processor configured to:
generate data representative of a volume, in an object space of an optical acquisition system, occupied by a set of rays of light passing through a pupil of said optical acquisition system and a conjugate of at least one pixel of a sensor of said optical acquisition system said volume occupied by said set of rays of light being called a pixel beam, and
generate a digital file comprising the data representative of said pixel beam, said data comprising:
parameters defining said pupil of the optical acquisition device,
parameters defining the smallest section of said pixel beam, called the waist, which corresponds to the conjugate, in the object space, of at least said pixel of the sensor, wherein said parameters defining the waist of said pixel beam are computed based on parameters defining said at least one pixel, and the parameters representing the waist of the pixel beam comprise a distance between the waist of the pixel beam and the center of the pupil, and an orientation of the waist of the pixel beam in a coordinate system associated to the optical acquisition system.
5. The apparatus according to claim 4 wherein parameters representing an intensity of the light captured by said pixel obtained from light field data captured by the optical acquisition device, are associated to the parameters representative of the pixel beam in the digital file.
6. The apparatus according to claim 5 wherein the parameters defining the pupil comprise a radius of the pupil, coordinates of the pupil center in the coordinate system associated to the optical acquisition device, and angles defining an orientation of the pupil in said coordinate system.
7. A light field imaging device comprising:
an array of micro lenses arranged in a regular lattice structure;
a photosensor configured to capture light projected on the photosensor from the array of micro lenses, the photosensor comprising sets of pixels, each set of pixels being optically associated with a respective micro lens of the array of micro lenses; and
at least one processor configured to provide a digital file comprising data representative of a volume, in an object space of an optical acquisition system, occupied by a set of rays of light passing through a pupil of said optical acquisition system and a conjugate of at least one pixel of a sensor of said optical acquisition system, said volume occupied by said set of rays of light being called a pixel beam, wherein the data representative of the pixel beam comprises:
parameters defining said pupil of the optical acquisition device,
parameters defining the smallest section of said pixel beam, called the waist, which corresponds to the conjugate, in the object space, of at least said pixel of the sensor,
wherein said parameters defining the waist of said pixel beam are computed based on parameters defining said at least one pixel, and the parameters representing the waist of the pixel beam comprise a distance between the waist of the pixel beam and the center of the pupil, and an orientation of the waist of the pixel beam in a coordinate system associated to the optical acquisition system.
8. The light field imaging device of claim 7 , wherein the data representative of the pixel beam further comprises parameters representing an intensity of the light captured by said pixel.
9. The light field imaging device of claim 8 , wherein the parameters defining the pupil comprise a radius of the pupil, coordinates of the pupil center in a coordinate system associated to the optical acquisition device, and angles defining an orientation of the pupil in said coordinate system.
10. A device for rendering an image from light field data comprising:
at least one processor configured to
obtain a digital file comprising data representative of a volume, in an object space of an optical acquisition system, occupied by a set of rays of light passing through a pupil of said optical acquisition system and a conjugate of at least one pixel of a sensor of said optical acquisition system said volume occupied by said set of rays of light being called a pixel beam, and
process the light field data based on the data in the digital file to render the image, wherein the data representative of the pixel beam comprises
parameters defining said pupil of the optical acquisition device,
parameters defining the smallest section of said pixel beam, called the waist, which corresponds to the conjugate, in the object space, of at least said pixel of the sensor,
wherein said parameters defining the waist of said pixel beam are computed based on parameters defining said at least one pixel, and the parameters representing the waist of the pixel beam comprise a distance between the waist of the pixel beam and the center of the pupil, and an orientation of the waist of the pixel beam in a coordinate system associated to the optical acquisition system.
11. The device of claim 10 , wherein the data representative of the pixel beam further comprises parameters representing an intensity of the light captured by said pixel.
12. The device of claim 11 , wherein the parameters defining the pupil comprise a radius of the pupil, coordinates of the pupil center in a coordinate system associated to the optical acquisition device, and angles defining an orientation of the pupil in said coordinate system.
13. A non-transitory computer readable medium storing program instructions that, when executed by a processor, generate a digital file comprising data representative of a volume, in an object space of an optical acquisition system, occupied by a set of rays of light passing through a pupil of said optical acquisition system and a conjugate of at least one pixel of a sensor of said optical acquisition system said volume occupied by said set of rays of light being called a pixel beam, said data comprising:
parameters defining said pupil of the optical acquisition device,
parameters defining the smallest section of said pixel beam, called the waist, which corresponds to the conjugate, in the object space, of at least said pixel of the sensor, wherein said parameters defining the waist of said pixel beam are computed based on parameters defining said at least one pixel, wherein the parameters representing the waist of the pixel beam comprise a distance between the waist of the pixel beam and the center of the pupil, and an orientation of the waist of the pixel beam in a coordinate system associated to the optical acquisition system, and
an intensity of the light captured by said pixel obtained from light field data captured by the optical acquisition system.