IMAGE PROCESSING APPARATUS AND METHOD
A location predicting unit predicts a composing location based on the composing locations corresponding to partial images of one-frame-before and two-frames-before the current partial image on an assumption that the above partial image moves at a constant speed, and gives the above predicted value to a combining unit as an initial value. The combining unit moves locations of the current partial image and the one-frame-before partial image pixel by pixel in a predetermined direction starting from the initial value and combines the above partial images each other. A picture element comparing unit and a location determining unit calculate the cumulative value of the brightness differentials between picture elements of the current partial image and the one-frame-before partial image in the overlapped part with respect to each of the combining locations. In the above operation, the calculation of the cumulative value corresponding to the currently-calculated combining location is finished when the above currently-calculated cumulative value exceeds the cumulative value corresponding to the already-calculated combining location.
1 . An image processing unit for producing composite images by overlapping partial images captured by relative movement of an image to be read and an image sensor within narrower reading range than that of reading object of the image, the image processing unit comprising:
a cumulative value calculation means for calculating a cumulative value of brightness differences of each pixels belonging to overlapped portion which are obtained by overlapping a current partial image and a one-frame-before partial image pixel-by-pixel;
a composing position determination means for generating a combining location, as a composing location, having a minimum cumulative value among the cumulative value calculated by the cumulative value calculation means; and
an image composition means for composing the current partial image and the one-frame-before partial image based on the composing location, wherein the cumulative value calculation means completes a process for combining location in calculation, when currently cumulated value exceeds the calculated cumulative value during the calculation of the cumulative values for each combining location.
2 . The image processing unit of claim 1 , further including:
a location predicting means for calculating a moving speed of partial images based on composing location of the one-frame-before partial image and the two-frames-before partial image, generating a composing-location initial value by predicting a composing-location of the current partial image based on the moving speed, and giving the initial value to the cumulative value calculation means,
wherein the cumulative value calculation means is configured to control a composing-location order of combining the current partial image and the previous partial image according to the initial value.
3 . The image processing unit of claim 1 , further comprising:
a location predicting means for calculating a moving speed and acceleration speed of partial image based on the one-frame-before partial image composing-location, the two-frames-before partial image composing-location, and the three-frames-before partial image composing-location, generating a initial value of composing-location by predicting a composing-location of the current partial image based on the moving speed and the acceleration speed, and giving the initial value to the cumulative value calculation means,
wherein the cumulative value calculation means controls an order of combining the current partial image and the 25 one-frame-before partial image based on the initial value.
4 . The image processing apparatus of claim 2 , wherein said cumulative value calculation means calculates the cumulative value corresponding to each of the combining locations by moving the combining location in a predetermined direction and recalculates the cumulative value by moving the combining location pixel-by-pixel from an initial combining location, when the combining location reaches the maximum or minimum position.
5 . An image processing method for producing composite images by overlapping partial images captured by relative movement of an image to be read and an image sensor within narrower reading range than that of reading object of the image, the image processing method comprising the steps of:
an initial value generating step for generating an initial combining location value of a current partial image based on combining locations corresponding to each of a plurality of combining location for previous partial images;
a cumulative value calculation step for completing a calculation of cumulative value of a currently-calculated combining location when currently-calculated cumulative value exceeds the cumulative value of an already-calculated combining location and continuing said calculation when the currently-calculated cumulative value does not exceeds the cumulative value of already-calculated combining location, wherein the calculation is done by calculating a cumulative value of brightness difference between picture elements in an overlapped part, the overlapped part is a portion of images that is configured by combining a current partial image and a one-frame-before partial image after moving said current partial image and said one-frame-before partial image from an initial location to a predetermined direction one by one;
a location determining step for generating a combining location with a minimum cumulative value among said calculated cumulative values; and
an image composing step for composing the current partial image and the one-frame-before partial image based on the composing location.
6 . The image processing method of claim 5 , wherein said cumulative value calculating step is configured to calculate the cumulative value corresponding to each of the combining locations by moving the combining location in a predetermined direction starting from the initial location, and subsequently moving the combining location in a reverse direction pixel by pixel when the current combining location reaches a maximum position or a minimum position.
7 . The image processing method of claim 5 , wherein the initial value generating step is configured to calculate a moving speed of partial images based on composing locations of the one-frame-before partial image and the two-time-before partial image, and generate a composing-location initial value by predicting a composing location of the current partial image based on the moving speed.
8 . The image processing method of claim 5 , wherein the initial value generating step is configured to calculate a moving speed and an acceleration speed of partial images based on composing locations of the one-frame-before partial image, the two-frames-before partial image, and the three-frames-before partial image, and generate a composing-location initial value by predicting a composing location of the current partial image based on said moving speed and said acceleration speed.