Abstract: A medical X-ray image processing apparatus, comprising an X-ray sensor which converts an image of X-rays penetrated an object into an electric signal using a solid-state image sensor and a data processor which processes the electric signal to generate an electric image signal corresponding to the X-ray image, compares the data of each picture element derived from the above-mentioned solid-state image sensor with the data of picture elements being adjacent to the picture element and present within a certain region, and corrects the data of the picture element referring to the data of the above-mentioned adjacent picture elements only when the data of the picture element is exceptionally different from the data of the adjacent picture elements by a predetermined reference value or more.

Abstract: A dental handpiece having therein a non-contact rotating speed detection device which includes an electromagnetic induction pulse generator including a permanent magnet provided close to the rotor in the head of a dental handpiece and a coil wound around the permanent magnet, and a rotor made of a magnetic material provided with recesses and/or projections around its circumference. The handpiece according to the invention facilitates to accurately detect rotor speed by detecting a pulse voltage proportionate to the rotation speed and therefore is useful for dental treatment and experiments.

Abstract: The disclosure relates to improvements in a hydraulically-actuated control device used in an operation unit of treatment chair and the like in an interlocking relation with reciprocating movement of a hydraulic piston. The device is of the construction in which two control valves slow in closing and opening operation are disposed in the oil supply and discharge passages leading to a hydraulic cylinder having a hydraulic piston therein so as to prevent shock in starting and stopping of the operation unit by controlling opening and closing of the two control valves and operation of the hydraulic pump disposed in the oil supply passage.

Abstract: This disclosure relates to a control device of transmitting an ultrasonic pulse from an ultrasonic transmitter to an ultrasonic receiver by disposing the transmitter and the receiver between two movable members which are placed in a variable relation in linear distance with each other, converting aerial propagation time of the pulse from the transmitter to the receiver into an electrical means, memorizing and holding a distance between the two members by the electrical means, and reading the memorized distance at any desired time and reproducing the distance. The disclosure also relates to a control device using the system.

Abstract: The disclosure relates to a system of automatically controlling the distance between two members placed in a relatively variable relation with each other with respect to distance on a straight line. One of the two members is provided with a transmitter capable of generating an ultrasonic pulse excellent both in directivity and in damping characteristics, and the other is provided with a receiver with the same in characteristics as the transmitter and which is disposed in an opposed relation with respect to the transmitter. The distance between the two members is automatically controlled by causing an ultrasonic pulse to be transmitted and received respectively by the transmitter and the receiver.