1. A method for automatic Computed Radiography (CR) image composition by white band detection and consistency rechecking, comprising the steps of: receiving an original CR image pair for composition; for each image in the original CR image pair, generating a horizontal gradient image and a vertical gradient image; projecting the vertical gradient image onto a y-axis of the each image to obtain a y-axis projection; identifying candidate edge positions from among at least two white band edge positions according to a relative value of each of the at least two white band edge positions with respect to a percentage value of an absolute maximum value of the y-axis projection; determining an intensity change constancy of the candidate edge positions to identify the candidate edge positions having orientation angles less than a pre-defined threshold angle with respect to a horizontal, the orientation angles being orthogonal with respect to angles of maximum intensity change for pixels on the candidate edge positions; determining an intensity change value to verify intensity value differences on two sides of the candidate edge positions with respect to predefined criteria; defining an error function to respectively obtain an error value for each of the candidate edge positions with respect to the intensity change constancy and the intensity change value; selecting the candidate edge positions having the error value below a pre-specified threshold; computing a cross-correlation score for the selected candidate edge positions, by comparing a consistency of the selected candidate edge positions against image data corresponding to the original image pair; and identifying a final overlap for the original image pair, based upon the cross-correlation score.