Light field imaging device
A light-field capture device including a photo-sensor, a main lens configured to refract light from a scene towards an image focal field, a micro-lens array positioned in the image focal field between the main lens and the photo-sensor, each micro-lens being configured to project a micro-lens image onto a respective dedicated area of the photo-sensor. The light-field capture device is provided with at least one compressive sensing calculation unit connected to at least one of the dedicated areas and configured to calculate data such as for example standard deviation data representative of the homogeneity of input pixels of said dedicated area, and to provide output data representative of the input pixels of said dedicated area; the output data comprising either a number of output pixels corresponding to the number of input pixels, or a single output pixel, depending on the relative value of the homoegeneity compared with a threshold.
1. A light-field capture device comprising:
a photo-sensor,
a main lens configured to refract light from a scene towards an image focal field,
a micro-lens array positioned in the image focal field between the main lens and the photo-sensor, each micro-lens being configured to project a micro-lens image onto a respective area of the photo-sensor; wherein the light-field capture device comprises at least one calculation unit connected to at least one of the respective areas and configured to obtain homogeneity data representative of the homogeneity of input pixels of said respective area, and to provide, based on the homogeneity data, output data representative of the input pixels of said respective area; the output data comprising either a number of output pixels corresponding to the number of input pixels, or a single output pixel, depending on a comparison of the homogeneity data with a homogeneity threshold,
a field lens positioned between the main lens and the micro-lens array, said field lens being configured to set the angle of refraction of the light refracted by the field lens, said field lens comprising a varifocal lens that is configured to adapt its object focal length to match a distance between the main lens and the varifocal lens; and
wherein light rays that pass through a center of an aperture of the varifocal lens are parallel to an optical axis behind the varifocal lens, wherein the light rays refracted by the micro-lens are parallel to the optical axis and perpendicular to the photo-sensor.
2. The light field capture device according to claim 1 , wherein the homogeneity data corresponds to the standard deviation of the input pixels.
3. The light field capture device according to claim 1 , wherein the at least one compressive sensing calculation unit is further configured to correct the vignetting effects of the light-field capture device.
4. The light field capture device according to claim 1 , wherein the photo-sensor is positioned at one image focal length (f μ ) from the micro-lens array.
5. The light-field capture device according to claim 1 , comprising a plurality of compressive sensing calculation units, wherein each compressive sensing calculation unit is connected to a single dedicated area.
6. The light field capture device according to claim 1 , wherein at least one compressive sensing calculation unit is individually connected to a plurality of dedicated areas of the photo-sensor.
7. A method for acquiring output data from a number of input pixels of a photo-sensor of a light-field capture device, said light-field capture device comprising a main lens configured to refract light from a scene towards an image focal field, a microlens array positioned in the image focal field between the main lens and the photo-sensor, a field lens positioned between the main lens and the microlens array, said field lens being configured to set the angle of refraction of the light refracted by the field lens, said field lens comprising a varifocal lens that is configured to adapt its object focal length to match a distance between the main lens and the varifocal lens,
the method comprising:
obtaining homogeneity data representative of the homogeneity of the input pixels to provide output data representative of the input pixels, wherein
in the case where the homogeneity data is equal to or greater than a threshold, the output data comprising a number of output pixels corresponding to the number of input pixels when the homogeneity data is equal to or greater than a threshold, otherwise, in the case where the homogeneity data is less than the threshold, the output data comprising a single output pixel representative of the input pixels when the homogeneity data is less than the threshold;
wherein light rays that pass through a center of an aperture of the varifocal lens are parallel to an optical axis behind the varifocal lens, wherein the light rays refracted by the microlens are parallel to the optical axis and perpendicular to the photo-sensor.
8. The method according to claim 7 wherein obtaining the homogeneity data comprises calculating the standard deviation of the input pixels.
9. The method according to claim 7 , wherein the value of the single output pixel is representative of the average value of the input pixels.
10. The method according to claim 7 , further comprising, before obtaining the homogeneity data, correcting the input pixels based on pre-set corrective weights.
11. The method according to claim 7 , wherein the output data comprise:
a header indicating the number of output pixels,
a body indicating the value of each output pixel.
12. A non-transitory computer-readable medium comprising a computer program product recorded thereon and capable of being run by a processor, including program code instructions for implementing a method for acquiring output data from a number of input pixels of a photo-sensor of a light-field capture device, said light-field capture device comprising a main lens configured to refract light from a scene towards an image focal field, a microlens array positioned in the image focal field between the main lens and the photo-sensor, a field lens positioned between the main lens and the microlens array, said field lens being configured to set the angle of refraction of the light refracted by the field lens, said field lens comprising a varifocal lens that is configured to adapt its object focal length to match a distance between the main lens and the varifocal lens,
the method comprising:
obtaining homogeneity data representative of the homogeneity of the input pixels to provide output data representative of the input pixels, wherein
in the case where the homogeneity data is equal to or greater than a threshold, the output data comprising a number of output pixels corresponding to the number of input pixels when the homogeneity data is equal to or greater than a threshold, otherwise, in the case where the homogeneity data is less than the threshold, the output data comprising a single output pixel representative of the input pixels when the homogeneity data is less than the threshold;
wherein light rays that pass through a center of an aperture of the varifocal lens are parallel to an optical axis behind the varifocal lens, wherein the light rays refracted by the microlens are parallel to the optical axis and perpendicular to the photo-sensor.