Method of presenting wide dynamic range images and a system employing same

A method of converting an input wide dynamic range (WDR) image into an output low dynamic range (LDR) image, the pixels of the input WDR image having a first dynamic range RWDR and the pixels of the output LDR image having a second dynamic range RLDR smaller than the first dynamic range, the method comprising:

• representing each intensity value x within the first range RWDR as x=m×rs with m being an mantissa of x, r being a radix, s being an exponent of x, and × representing multiplication;
• partitioning the first range RWDR into a plurality of input intervals Xi with i being an integer integer and i≥0, based at least on values of the exponents within the first range RWDR, the input intervals Xi being non-overlapped and spanning the first dynamic range RWDR;
• obtaining a transfer function ƒ(x) over the first dynamic range RWDR, the transfer function ƒ(x) comprising a plurality of sub-functions ƒi(x), each sub-function ƒi(x) being determined over one of the input intervals Xi of the first dynamic range RWDR;
• determining the intensity y(p) of each pixel p of the output LDR image by using the transfer function ƒ(x) and at least the intensity value x(p) of the corresponding pixel p of the input WDR image;
• and
• outputting the output LDR image.

A system for converting an input WDR image into an output LDR image, the pixels of the input WDR image having a first dynamic range RWDR and the pixels of the output LDR image having a second dynamic range RLDR smaller than the first dynamic range, the system comprising:

• an input for inputting the input WDR image;
• an output for outputting the output LDR image;
• and
• a processing structure functionally coupled to the input and the output, the processing structure being configured for:
• representing each intensity value x within the first range RWDR as x=m×rs with m being an mantissa of x, r being a radix, s being an exponent of x, and × representing multiplication;
• partitioning the first range RWDR into a plurality of input intervals Xi with i being an integer integer and i≥0, based at least on values of the exponents within the first range RWDR, the input intervals Xi being non-overlapped and spanning the first dynamic range RWDR;
• obtaining a transfer function ƒ(x) over the first dynamic range RWDR, the transfer function ƒ(x) comprising a plurality of sub-functions ƒi(x), each sub-function ƒi(x) being determined over one of the input intervals X1 of the first dynamic range RWDR;
• determining the intensity y(p) of each pixel p of the output LDR image by using the transfer function ƒ(x) and at least the intensity value x(p) of the corresponding pixel p of the input WDR image;
• and
• outputting the output LDR image.

A computer-readable storage device comprising computer-executable instructions for converting an input WDR image to an output LDR image, the pixels of the input WDR image having a first dynamic range RWDR and the pixels of the output LDR image having a second dynamic range RLDR smaller than the first dynamic range, wherein the instructions, when executed, executed, cause a processing structure to act for:

• representing each intensity value x within the first range RWDR as x=m×rs with m being an mantissa of x, r being a radix, s being an exponent of x, and × representing multiplication;
• partitioning the first range RWDR into a plurality of input intervals Xi with i being an integer integer and i≥0, based at least on values of the exponents within the first range RWDR, the input intervals Xi being non-overlapped and spanning the first dynamic range RWDR;
• obtaining a transfer function ƒ(x) over the first dynamic range RWDR, the transfer function ƒ(x) comprising a plurality of sub-functions ƒi(x), each sub-function ƒi(x) being determined over one of the input intervals Xi of the first dynamic range RWDR;
• determining the intensity y(p) of each pixel p of the output LDR image by using the transfer function ƒ(x) and at least the intensity value x(p) of the corresponding pixel p of the input WDR image;
• and
• outputting the output LDR image.