Method and apparatus for relating and combining multiple images of the same scene or object(s)

A method of aligning a plurality of images having common subject matter, each image being encoded as an ordered set of pixels each having at least one associated pixel parameter, the method comprising:

• a. analyzing first and second images to identify pixels corresponding to common subject matter therebetween and spatially related by a first projective coordinate transformation;
• b. approximating the first projective coordinate transformation;
• c. projectively transforming the first image using the approximate projective coordinate transformation to produce an intermediate image;
• d. analyzing the intermediate and second images to identify pixels corresponding to common subject matter therebetween and spatially related by a second projective coordinate transformation;
• e. approximating the second projective coordinate transformation;
• f. accumulating the approximate projective coordinate transformations into a composite transformation relating the first image to the second image;
• g. applying the composite transformation to the first image to thereby transform it into a processed image, the common subject matter encoded by pixels in the processed image being substantially spatially consistent with the common subject matter encoded by pixels in the second image;
• and
• h. aligning the images by combining the pixels corresponding to the common subject matter.

Apparatus for aligning first and second images having common subject matter comprising:

• a. first and second computer memories for storing each image as an ordered set of pixels each having at least one associated pixel parameter;
• b. analysis means for featurelessly approximating parameters of a projective coordinate transformation that spatially relates pixels corresponding to common subject matter of the first and second images;
• and
• c. image-processing means for (i) applying the parameters to the contents of the first computer memory to thereby transform them into a processed image, the common subject matter encoded by pixels in the processed image being substantially spatially consistent with the common subject matter encoded by pixels in the second computer memory, and (ii) aligning the images by combining the pixels corresponding to the common subject matter.

A visual thesaurus comprising:

• a. a database of images each stored as an ordered set of pixels, each pixel having at least one associated pixel parameter;
• b. first and second computer memories for storing a reference image and a database image;
• c. analysis means for sequentially retrieving images from the database and storing each retrieved image in the second computer memory, the analysis means operating, for each retrieved image, on the first and second computer memories to detect the existence of common subject matter between the reference image and the database image by featurelessly determining whether pixels from the first computer memory can be related to pixels of the second computer memory according to a projective coordinate transformation, and if not, rejecting the database image as unrelated to the reference image;
• and
• d. an interface for displaying database images related to the reference image.