AUTOMATIC LUMINANCE ADJUSTMENT FOR HDR VIDEO CODING

Organization Name

Inventor(s)

AUTOMATIC LUMINANCE ADJUSTMENT FOR HDR VIDEO CODING

This abstract first appeared for US patent application 18833413 titled 'AUTOMATIC LUMINANCE ADJUSTMENT FOR HDR VIDEO CODING

Original Abstract Submitted

To obtain a practical yet versatile and accurate apparatus for luminance re-grading () of an input high dynamic range image (IM_HDR) of first luminance dynamic range into a second image (IM_DR) of second luminance dynamic range, the inventors propose the apparatus for luminance re-grading () of an input high dynamic range image (IM_HDR) of first luminance dynamic range into a second image (IM_DR) of second luminance dynamic range, wherein a maximum luminance of the second image may be higher or lower than a maximum luminance of the input high dynamic range image, the apparatus comprising:—a first neural network processing circuit (), having as input a set of pixel luminances of the input high dynamic range image (IM_HDR), wherein the first neural network processing circuit has at least two sets of outputs (S S), wherein the sets of outputs have output nodes for supplying parameter values of a parametric re-grading equation, wherein the parametric re-grading equation is composed of at least two partial functions an amount of which in the re-grading equation being controlled by at least two corresponding output parameter values (P P); wherein a first output set (S) comprises at least two parameter values (P P) which determine a first shape of the re-grading function, and a second output set (S) comprises at least two corresponding parameter values (P P) which determine an alternative second shape of the re-grading function, which being determined by the same parametric definition but using different values for its parameters gets a different shape;—a second neural network processing circuit (), which has as input at least one measurement value (La) from at least one sensor (), and as output nodes supplying a set of weights corresponding in amount to at least the number of sets of outputs of the first neural network processing circuit;—a combiner (), arranged to add a first parameter value (P) of the first output set of the first neural network processing circuit multiplied by a corresponding first weight (w) from the second neural network processing circuit, to a corresponding parameter value (P) for the same re-grading function defining parameter of the second output set of the first neural network processing circuit multiplied by a corresponding second weight (w) from the second neural network processing circuit, yielding a final parameter value (P_f); and—a luma mapping circuit () arranged to map input lumas of the input high dynamic range image (IM_HDR) with a luma mapping function (F_L) which is defined by at least two parameters comprising the final parameter value (P_f) to obtain output lumas of the second image (IM_DR).