Abstract: An apparatus for detection of flaws in currency having multiple misregistered images. Optical means scan a test note to provide a plurality of outputs each representative of a particular patch value of a particular scan line of the test note. Generating means provide a plurality of outputs each representative of a particular patch value of a particular scan line of a reference note which is generated in real time as the test note is scanned. The generating means includes means to insure that each generated reference patch value is provided for comparison with the corresponding patch value of the test note. Each reference patch value is generated for any value of misregistration between the multiple images within a predetermined tolerance.

Abstract: A registration system for use with a document inspection system wherein a test document is compared with a master document stored in a computer memory in which the registration system has means for aligning each point on the test document with its corresponding point of the stored master document. The document inspection system optically scans each point on the test document and provides real time input to a flaw detector. The registration system optically scans the leading corners of the test document and generates addresses to read out from memory each point on the master document in precise registration with its corresponding point on the test document corrected for misalignment of the test document relative to the stored master document.

Abstract: An optical system for detecting printing flaws on a printed sheet includes a plurality of detector arrays each with a plurality of detector elements positioned to scan a reference sheet and the test sheet. Each detector element in each array "sees" a small area of a test or a reference sheet as the sheets are scanned and the output of the detector elements are synchronized with each other and compared. When the output from the test array detector does not equal the output of the corresponding reference array detector and the system is synchronized, the system coupled thereto indicates that the two areas "seen" are unequal. A sufficient and pre-set number of unequal indications are required to decide whether the test sheet is sufficiently different from the reference sheet that it should be destroyed.

Abstract: A low reflectance reticle immersed in optical cement between transparent strates. A copper reticle is vacuum deposited upon one transparent substrate and chemically treated to produce anti-reflectance properties. The reticle and substrate to which it is attached are then cemented with optical cement to a second transparent substrate to immerse the anti-reflectance reticle between tranparent substrates in optical cement. The immersed reticle thus formed has superior anti-reflection properties and is protected from mechanical damage by its immersed location. Immersed reticles may be installed between elements of a compound lens if desired.