Abstract: Apparatus for measuring the Young's modulus or the internal damping coefficient of skin, for example human skin, in vivo, comprises a rectangular frame of non-metallic material to be adhered by means of double-sided adhesive tape to the surface of skin to be tested, and a movable assembly also adherable to the skin surface by means of tape.The frame carries a vibration exciter in the form of a coil co-operating with a magnetic bead on the movable means, and also an opto-electronic movement sensor comprising an optical transmitter and receiver mounted next to one another on the frame and an optical reflector on the movable means for reflecting back to the light receiver the beam emitted by the light transmitter.

Abstract: A coaxial optical fiber bundle assembly (Reference No. 6 in the following Specification and Drawing), carrying emitted light from a light source and received light which has been returned by an object illuminated from said light source, is moved towards the object (Reference No.: 7) to cause the intensity of the received light, as detected by a photo transistor in light emitter-receiver unit (Reference No.: 1), to attain a maximum value which is amplified and held as a display on digital voltmeter (Reference No.: 11). Comparison of the held value with the corresponding held maximum value resulting from a similar determination made of either a different object of the same object after a color change therein or thereof can thus be made on a numerical basis.

Abstract: The elastic properties of skin are measured by applying a torque to a disc placed in contact with a portion of the skin while holding a guard ring against skin around the region to define an annular skin sample to be stressed. Rotation of the disc is measured, and then the rotation is partially reversed and the torque-applying connection to the disc removed. The recovery rotation of the skin in the substantial absence of any applied torque is then measured.

Abstract: Measurements of the greasiness of skin are made by applying a plate against a region of skin to be studied and then inserting the plate in a recess of the casing, in register with a photodiode and a phototransistor. A series of n (in this case 5) indicator lamps is connected to a set of n-1 (in this case 4) comparators each comparing a respective voltage threshold level with the voltage delivered by the photoresistor, so that the voltage of the transistor, and hence the greasiness of the deposit on the plate through which luminous flux from the photodiode to the phototransistor passes by reflection from the upper side of the plate, can be determined by observing which lamps are illuminated.

Abstract: Apparatus for measuring the firmness of tissue, for example of skin in vivo, comprises a compartment open at one end and having a deformable bulb at the other end to allow the compartment near the open end to be subject to internal suction deforming a portion of skin against which the apparatus is applied to dome upwardly into the compartment. A plunger pressed upwardly by the doming skin actuates a pivotable pointer visible from outside the apparatus.