Tone selective adjustment of images

A system for image processing, the system comprising:

• a local adjustment tool to adjust an image including a plurality of pixels, the local adjustment tool including a shadow tone component and a highlight tone component, wherein:
• each of the shadow and highlight tone components is operable to determine a tone value and a corresponding local weight for adjustment for a location in the image by performing operations comprising:
• determining a neighborhood comprising an area of the image surrounding the location that is based on at least one of one or more neighborhood size parameters;
• determining a neighborhood intensity, the neighborhood intensity being a measure of values of a local attribute specified by pixels within the neighborhood;
• determining a tone value for the location, the tone value representing a characterization of a tone of the neighborhood, where the tone value is based on the neighborhood intensity and a tone function, where the tone function is based on at least one of one or more tone function shape parameters;
• and
• determining a local weight for a tone adjustment based on the tone value and at least one of one or more tone strength adjustment parameters;
• the local adjustment tool is operable to adjust the image at a location using the corresponding local weights determined by each of the shadow and highlight tone components according to the local weight specified by the corresponding tone value.

A computer readable storage device storing a computer program of instructions which, when executed by a computer processing apparatus, cause the apparatus to perform a method for processing an image comprising:

• identifying one or more neighborhood size parameters, one or more tone function shape parameters, and one or more tone adjustment strength parameters;
• and
• for each location of multiple locations within the image, performing tone selective adjustment, where performing tone selective adjustment comprises:
• determining a shadow neighborhood and a highlight neighborhood, each neighborhood comprising an area of the image surrounding the location that is based on at least one of the one or more neighborhood size parameters;
• determining a shadow neighborhood intensity for the shadow neighborhood, the shadow neighborhood intensity being a measure of values of a local attribute specified by pixels within the shadow neighborhood;
• determining a highlight neighborhood intensity for the highlight neighborhood, the highlight neighborhood intensity being a measure of values of a local attribute specified by pixels within the highlight neighborhood;
• determining a shadow tone value representing a characterization of a shadow tone of the neighborhood, where the shadow tone value is based on the shadow neighborhood intensity and a shadow tone function, where the shadow tone function is based on at least one of the one or more tone function shape parameters;
• determining a highlight tone value representing a characterization of a highlight tone of the neighborhood, where the highlight tone value is based on the highlight neighborhood intensity and a highlight tone function, where the highlight tone function is based on at least one of the one or more tone function shape parameters;
• determining a shadow local weight for a shadow tone adjustment based on the shadow tone value and at least one of the one or more tone strength adjustment parameters;
• determining a highlight local weight for a highlight tone adjustment based on the highlight tone value and at least one of the one or more tone strength adjustment parameters;
• adjusting the image at the location using the shadow local weight for shadow tone adjustment and the highlight local weight for highlight tone adjustment.