Solid state imagers typically consist of an array of pixel cells containing photosensors. Each pixel cell produces a signal corresponding to the intensity of light impinging on its photosensor when an image of a scene is focused on the array by one or more lenses. These signals may be stored in a memory and displayed on a monitor, manipulated by software, printed, or otherwise used to provide information about the scene.
Several kinds of imagers are generally known. Complementary metal-oxide-semiconductor (“CMOS”) imagers and charge coupled device (“CCD”) imagers are among the most common. CMOS imagers are discussed, for example, in U.S. Pat. No. 6,140,630, U.S. Pat. No. 6,376,868, U.S. Pat. No. 6,310,366, U.S. Pat. No. 6,326,652, U.S. Pat. No. 6,204,524, and U.S. Pat. No. 6,333,205, which are all assigned to Micron Technology, Inc.
To image a large scene (e.g., a panorama scene), a plurality of smaller images can be captured and later stitched together using software. FIG. 1 depicts an arrangement of three smaller images 101, 102, 103 which can be combined to form a larger composite image. The overlap areas 104, 105 of the smaller images are shaded with diagonal lines. Overlap area 104 corresponds to an area of the scene included in both image 101 and image 102. Similarly, overlap area 105 corresponds to an area of the scene included in both image 102 and image 103.
Smaller images must be carefully aligned to yield a satisfactory composite image. For example and again with reference to FIG. 1, if image 101 were not aligned with image 102, then an abrupt transition would be evident within overlap area 104 and image compositing software would have a difficult time properly stitching the images together. Conventionally, images are aligned to form a larger composite image after all of the smaller images have been captured, typically by software on a computer separate from the imager used to capture the smaller images. If adjacent smaller images cannot be sufficiently aligned (e.g., because the as-captured smaller images were vastly askew or do not share a sufficient overlap area), the resulting composite image may be unsatisfactory. Therefore, a method and system enabling a user to better align small images used to form a composite image is desirable.