Automated cropping of electronic images

An electronic image processor method, comprising:

• processing an electronic image to identify compositionally significant features within the image,
• sorting the compositionally significant features according to at least one compositional rule into those features which are to be included within cropped versions of the image and those features which are to be excluded from cropped versions of the image,
• automatically generating a plurality of candidate crops based on the sorted compositionally significant features, wherein each of the candidate crops is not merely the smallest crop that encloses a feature which is to be included,
• generating minimum and maximum crop limits for each of the candidate crops,
• identifying suitable crop candidate boundaries between the minimum and maximum crop limits for each of the candidate crops, by generating a measure of quality in accordance with at least one quality metric, and
• selecting a reduced number of crop candidates as output candidates based on the measure of quality generated in the identifying step.

An electronic image processor, comprising:

• an analyzer unit configured to analyse an image to identify compositionally significant features therein;
• a compositional rule application unit configured to apply at least one composition rule so as to generate a plurality of constraints;
• a candidate crop generation unit configured to apply the constraints to the image to generate a plurality of minimum and maximum candidate crops each one having a measurement associated therewith indicating the extent to which the constraints are violated;
• an identifying unit configured to identify suitable crop candidate boundaries between the minimum and maximum crop limits for each of the candidate crops, by generating a measure of quality in accordance with at least one quality metric;
• and
• a presenting unit configured to present at least one of the candidate crops to a user, in accordance with the generated measure of quality.

A method of using an electronic image processing device for cropping an electronic image, the image processing device comprising an image processing means, the image processing means including at least one of an electronic processor, firmware and software for processing the electronic image, wherein the method comprises the steps of using the image processing means to:

• i) process the electronic image to identify at least one feature relevant to the composition of the electronic image each such feature occupying a sub-region of the electronic image;
• ii) select at least one compositional rule from a set comprising a plurality of predetermined compositional rules, based on the relevance of the compositional rule(s) to at least one of the identified features;
• and
• iii) determine at least one suitable crop boundary for a plurality of crop candidates by applying one or more of the selected compositional rules,
• in which:
• step (i) includes identifying features which constitute non-overlapping segmented regions of interest;
• step (iii) is achieved by first selecting alternative divisions of said identified regions of interest into those which will be included by the crop boundary and those which will be excluded by the crop boundary;
• each such alternative division of regions of interest is used to determine an inner crop boundary limit and an outer crop boundary limit such that the inner crop boundary limit is the smallest boundary which circumscribes the regions of interest to be included and the outer crop boundary limit is the largest boundary which excludes the regions of interest to be excluded;
• and
• said one or more suitable crop boundaries are determined between the limits of the inner and outer crop boundary limits for each of said alternative divisions of regions of interest.

A method of cropping an electronic image, comprising the steps of:

• i) processing the image to identify at least one distinct feature within the image,
• ii) selecting at least two compositional rules relevant to the at least one feature, the compositional rules determining the possible inclusion and placement of the feature within a cropped version of the image;
• iii) determining at least one minimum and at least one maximum crop boundary for a cropped version of the image in accordance with the selected compositional rules;
• and
• iv) determining an appropriate crop boundary between the minimum and maximum crop boundary for the image, based on at least one of:
• a) lowest brightness level as compared to adjacent regions, b) smallest color activity as compared to adjacent regions, and c) lowest saliency as compared to adjacent regions, the appropriate crop boundary corresponding to a particular column of the image, the adjacent regions corresponding to left and right columns of the image abutting the particular column.