Evaluation Measure for Images

A method for determining an evaluation measure for an image, the method comprising:

• performing, for each tone mapper setting value among a set of multiple tone mapper setting values, each tone mapper setting value representing a respective shutter speed, the steps of:
• creating a tone mapped version of said image;
• creating a tone mapped version of a version of said image obtained following compression of said image;
• and
• calculating an error over a non-excluded subset of pixels in said tone mapped version of said image and in said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculating a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said multiple tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculating said evaluation measure based on said mean squared error.

An image encoding method comprising:

• compressing at least a portion of an image according to multiple compression modes to obtain multiple compressed versions of said at least a portion of said image;
• determining, for each compression mode of said multiple compression modes, a respective evaluation measure for said image;
• and
• selecting a compressed version of said at least a portion of said image as an encoded representation of said at least a portion of said image based on said multiple evaluation measures;
• wherein said determining of the respective evaluation for said image comprises:
• performing, for each tone mapper setting value among a set of multiple tone mapper setting values, each tone mapper setting value representing a respective shutter speed, the steps of:
• creating a tone mapped version of said image;
• creating a tone mapped version of a version of said image obtained following compression of said image;
• and
• calculating an error over a non-excluded subset of pixels in said tone mapped version of said image and in said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculating a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said multiple tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculating said evaluation measure based on said mean squared error.

An encoder for determining an evaluation measure for an image, said encoder comprising processing circuitry configured to:

• create, for each tone mapper setting value among a set of multiple tone mapper setting values, each tone mapper setting value represents a respective shutter speed, a tone mapped version of said image;
• create, for each tone mapper setting value among said set of multiple tone mapper setting values, a tone mapped version of a version of said image obtained following compression of said image;
• calculate, for each tone mapper setting value among said set of multiple tone mapper setting values, an error over a non-excluded subset of pixels in said tone mapped version of said image and said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculate a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said multiple tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculate said evaluation measure based on said mean squared error.

An encoder for determining an evaluation measure for an image, the encoder comprising processing circuitry configured to:

• create, for each tone mapper setting value among a set of multiple tone mapper setting values, each tone mapper setting value represents a respective shutter speed, a tone mapped version of said image and a tone mapped version of a version of said image obtained following compression of said image;
• calculating, for each tone mapper setting value among said set of multiple tone mapper setting values, an error over a non-excluded subset of pixels in said tone mapped version of said image and said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculate a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculate said evaluation measure based on said mean squared error.

An image encoding device comprising processing circuitry configured to:

• compress at least a portion of an image according to multiple compression modes to obtain multiple compressed versions of said at least a portion of said image;
• determine, for each compression mode of said multiple compression modes, a respective evaluation measure for said image;
• and
• select a compressed version of said at least a portion of said image as an encoded representation of said at least a portion of said image based on said multiple evaluation measures;
• wherein the processing circuitry is configured determine the respective evaluation for said image, for each compression mode of said multiple compression modes, by:
• performing, for each tone mapper setting value among a set of multiple tone mapper setting values, each tone mapper setting value representing a respective shutter speed, the steps of:
• creating a tone mapped version of said image;
• creating a tone mapped version of a version of said image obtained following compression of said image;
• and
• calculating an error over a non-excluded subset of pixels in said tone mapped version of said image and in said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculating a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said multiple tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculating said evaluation measure based on said mean squared error.

A non-transitory computer-readable medium comprising computer program instructions stored thereon, which computer program instructions are configured so that, when executed by a processor, the computer program instructions cause said processor to:

• create, for each tone mapper setting value representing among a set of multiple tone mapper setting values, each tone mapper setting value represents a respective shutter speed, a tone mapped version of said image and a tone mapped version of a version of said image obtained following compression of said image;
• calculate, for each tone mapper setting value among said set of multiple tone mapper setting values, an error over a non-excluded subset of pixels in said tone mapped version of said image and said tone mapped version of said version of said image obtained following compression of said image, said non-excluded subset of pixels does not meet at least one exclusion criterion;
• calculate a mean squared error as an average error for said respective non-excluded subset of pixels in said multiple tone mapped versions of said image and said multiple tone mapped versions of said version of said image obtained following compression of said image;
• and
• calculate said evaluation measure based on said mean squared error.