Showing papers on "Standard test image published in 1970"

Focus and magnification adjustment of a high-performance camera

Abstract: A method and apparatus are disclosed for adjusting the location of the image and object planes of a camera to minimize focus and magnification errors. A special test reticle is used comprised of at least one, and preferably nine, test patterns on one side of the reticle. Over each pattern a first prism is mounted to tilt the apparent plane of the test pattern as seen in the prism and a second prism is ordinarily mounted to the other side of the reticle to compensate for the refraction due to the first prism. In use, the test reticle is placed in the object plane of the camera and a test image plate is exposed and developed. The sharpest points in the image of each of the tilted test patterns as well as the spacing between certain fiducial marks are then measured. From this data are derived the corrections that should be made in the positions of the object and image planes. With six to eight iterations of this procedure, good adjustment of the camera is achieved.