Abstract: An optical device for measuring and inspecting a physical and optical characteristic of an object. In the preferred embodiment, the optical device comprises a light source emitting a beam of light rays along an optical axis, a light-sensitive electronic device, preferably a charge-coupled device, positioned along the optical axis converting an image formed from the beam of light rays being reflected from the object into an electrical signal. An image rotating device, preferably a Dove prism, is positioned along the optical axis between the object and the light-sensitive electronic device. A rotating device rotates the image rotating device at an angle of rotation. The rotating device, preferably a d-c step motor, converts the angle of rotation of the image rotating device into an electrical signal. The angle of rotation of the image rotating device is based on a step position of the d-c step motor.

Abstract: A diagnostic method and indicator for heme in controlled sensitivity is provided by impregnating a bibulous body, such as a test strip with a solution of a color indicator in leuco form and drying and storing in stable active form, and in use applying to the strip a test sample containing heme. The test color is then developed in the strip by wetting the test sample and strip in contact therewith with a peroxide solution of a solvent for the leuco dye carrying the oxygen released from the peroxide by the heme peroxidase in the test sample, such as blood or body tissue or residues containing occult blood whose presence is to be determined.