Abstract: A photo installation having an acquisition element intended to receive the optical image of a subject desired to be photographed. The acquisition element is connected to a central processing unit for storing the optical information thus received. The installation is provided with a screen connected to the acquisition element that allows simultaneous viewing by the subject of the image received by the acquisition element. A printing device is provided to take a photograph or a sequence of photographs upon command of the subject. A half-silvered mirror is mounted on the optical axis of the acquisition element and directed along the bisector of the angle defined by the respective optical axes of the acquisition element and the screen so as to generate a virtual image of the screen on the optical path of the acquisition element.

Abstract: An automatic installation for the composition and continuous printing of small texts, including a console having a screen and a control keyboard, and a microcomputer for processing instructions transmitted by the keyboard and for transmitting them partly to the screen and partly to a printer for printing the text composed onto a medium. The microcomputer additionally manages the whole of the installation and the interaction between the latter and the user. The printer is a printer of the graphics type. The composition proper of the text to be printed is managed by a program adapted to this end and loaded into the memory of the microcomputer. The whole of the text to be printed is previously composed by the user with the aid of a program stored in the microcomputer before being printed.

Abstract: Acoustic well-logging methods and apparatus are provided for investigating earth formations traversed by a borehole. Acoustic waves are transmitted from different points in the borehole and received at other points in the borehole, and a reception signal is generated representative of the received acoustic waves. The time interval between the instant the measurement waves are transmitted and the instant the instantaneous amplitude of the reception signal exceeds a given detection threshold for the first time is measured as a function of depth and the value of the detection threshold is adjusted during each measurement sequence in accordance with the amplitude of the noise received during the next preceding listening interval.