US 11,057,593 B2
Method for reconstructing a colour image acquired by a sensor covered with a mosaic of colour filters
David Alleysson, Moirans (FR); and Prakhar Amba, Grenoble (FR)
Assigned to CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR)
Appl. No. 16/977,915
Filed by CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR)
PCT Filed Feb. 20, 2019, PCT No. PCT/EP2019/054222
§ 371(c)(1), (2) Date Sep. 3, 2020,
PCT Pub. No. WO2019/170420, PCT Pub. Date Sep. 12, 2019.
Claims priority of application No. 1851978 (FR), filed on Mar. 7, 2018.
Prior Publication US 2020/0413012 A1, Dec. 31, 2020
Int. Cl. H04N 9/04 (2006.01); G06T 3/40 (2006.01)
CPC H04N 9/04515 (2018.08) [H04N 9/0455 (2018.08); H04N 2209/046 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for reconstructing a colour image acquired by a photosensitive sensor of size H×W, covered with a mosaic, of size H×W, of P filters of different colours making up a base pattern of size h×w such that h<H and w<W, said base pattern of the mosaic of filters being repeated so as to cover the mosaic of filters without overlap between the base patterns, said method being carried out by computer and comprising at least the following steps:
a first preliminary step of constructing a demosaicing matrix D starting from a simulation using a first database of N images Ii, i∈[1, . . . , N], with P colour components, called reference images, for producing a second database of N images Ji, i∈[1, . . . , N] simulating images produced originating from the sensor, after acquisition by said sensor of the images of the first database, said reference images Ii and images produced Ji being represented respectively in the form of matrices of HW/(hw) vectors y1, x1 such that:
the components of y1 are the P components of a reduced neighbourhood of size nh×nw of one of the HW/(hw) base patterns applied to the reference image Ii,
the components of x1 are the components of a reduced neighbourhood of size nh×nw of one of the HW/(hw) base patterns applied to the image produced Ji,
with nh>h and nw>w; and
a second step of reconstructing a colour image producing the product of the demosaicing matrix D with a matrix representation of a mosaic image originating from the sensor after acquisition of the colour image by said sensor, said product of the demosaicing matrix D with the matrix representation of the mosaic image using an interpolation of the colour of each pixel of the mosaic image as a function of a neighbourhood, of size nh×nw pixels, of a base pattern (43) of size h×w, corresponding to the base pattern of the mosaic of filters.