Method and device for processing and for searching for an object by signals corresponding to images

1. A method of representing an object appearing in an image or a sequence of images, using at least one processor to process signals corresponding to a two-dimensional outline of the object, the method comprising:

deriving, using said at least one processor, a plurality of numerical values representing features appearing on the outline of the object based on the signals; and

applying a transformation to the derived values to generate a representation of the outline,

wherein the transformation is in the form of y′=a pow(y,b)+c, and

further wherein a, b and c are constants, y is a value being transformed, y′ is a result of the transformation, and pow(y,b) denotes y to the power b, and

further wherein b is greater than zero and less than 1.

2. A method as claimed in claim 1 wherein b is between 0.25 and 0.75, inclusive.

3. A method as claimed in claim 2 wherein b=0.5.

4. A method of searching for an object in an image or sequence of images using at least one processor to process signals corresponding to images, the method comprising inputting a query in the form of a two-dimensional outline, deriving a descriptor of said outline using a processor to perform method as claimed in claim 1 , obtaining a descriptor of objects in stored images derived using a method as claimed in claim 1 and comparing said query descriptor with each descriptor for stored object, and selecting and displaying at least one result corresponding to an image containing an object for which the comparison indicates a degree of similarity between the query and said object.

5. The method of claim 4 , further comprising providing as output the degree of similarity associated with a reference object.

6. The method of claim 4 , wherein the reference representation is stored in a reference database.

7. The method of claim 1 , wherein the derived values comprise numbers representing at least one peak of a characteristic curve representing an outline of an object in CSS image space.

8. The method of claim 7 , wherein y represents the peak height value of a peak of a characteristic curve.

9. The method of claim 1 , wherein the representation of the outline generated by the transformation is invariant under changes of imaging conditions comprising changes in scale, rotations, deformations of the outline, and projective transformation.

10. The method of claim 1 , wherein the representation of the outline generated by the transformation is insensitive to shape variability within a broader shape class.

11. A computer-readable medium having embodied thereon a program which, when executed, causes a computing device to perform a method of representing an object appearing in an image or a sequence of images by processing signals corresponding to a two-dimensional outline of the object, the method comprising:

deriving a plurality of numerical values representing features appearing on the outline of the object based on the signals; and

applying a transformation to the derived values to generate a representation of the outline,

wherein the transformation is in the form of y′=a pow(y,b)+c, and

further wherein a, b and c are constants, y is a value being transformed, y′ is a result of the transformation, and pow(y,b) denotes y to the power b, and

further wherein b is greater than zero and less than 1.

12. A computer-readable medium having embodied thereon a program which, when executed, causes a computing device to perform a method of searching for an object in an image or sequence of images by processing signals corresponding to images, the method comprising inputting a query in the form of a two-dimensional outline, deriving a descriptor of said outline using a method as claimed in claim 1 , obtaining a descriptor of objects in stored images derived using a method as claimed in claim 1 and comparing said query descriptor with each descriptor for stored object, and selecting and displaying at least one result corresponding to an image containing an object for which the comparison indicates a degree of similarity between the query and said object.

13. An image transformation device that generates a representation of an object in an image or a sequence of images by processing an input signal corresponding to a two-dimensional outline of the object, the device comprising:

a numerical derivation unit that derives a plurality of numerical values representing features on the outline of the object; and

a feature transformer that generates a representation of the outline by transforming the derived values, wherein the transformation is in the form of y′=a pow(y,b)+c, and

further wherein a, b and c are constants, y is a value being transformed, y′ is a result of the transformation, and pow(y,b) denotes y to the power b, and

further wherein b is greater than zero and less than 1.

14. An image comparison device, the device comprising:

a query descriptor generator that generates a query descriptor by providing an image signal corresponding to a two-dimensional outline of a query object as the input signal to the device of claim 13 ;

a reference descriptor retrieval unit that obtains reference descriptors of objects in stored images, where said reference descriptors were previously derived by providing two-dimensional outlines of said objects as input signals to the device of claim 13 ; and

a comparison and output unit that compares said query descriptor with each reference descriptor, and selects and displays at least one result corresponding to an image containing a reference object, from among said objects stored in images, for which the comparison indicates a degree of similarity between the query object and said reference object.

15. An image descriptor database system comprising:

a data intake portion that accepts image data as input;

an outline generator that generates an image signal representing a two-dimensional outline of an object in the image data;

a numerical derivation unit that derives a plurality of numerical values representing features appearing on the outline of the query object from the signal;

a control unit that generates a representation of the outline by transforming the derived values using a transformation in the form of y′=a pow(y,b)+c, wherein a, b and c are constants, y is a value being transformed, y′ is a result of the transformation, pow(y,b) denotes y to the power b, and b is greater than zero and less than 1;

an association engine that associates the representation with the input image data;

a descriptor database that stores the generated representation and its associated image.

16. The descriptor database system of claim 15 , further comprising:

a query handler that:

coordinates the data intake portion, outline generator, numerical derivation unit, and control unit to generate a query representation of two-dimensional outline of a query object stored in a query image;

compares the query representation with at least one stored generated representation stored in the descriptor database;

determines a degree of similarity between the at least one stored generated representation and the query object; and

selects and displays the stored associated image of said at least one stored generated representation based on the degree of similarity.