INFORMATION DISPLAY SYSTEM

B. N. EPIFANTSEV, Yu. P. ZABASHTA, B. Ya. MASLOV

(Presented by the scientific seminar of the automation sector of the Scientific Research Institute of Electronic Introscopy)

In information-display technology, the most complete information on the state of monitored objects or media can be obtained by using television principles of scanning and image reproduction. This explains the widespread penetration of television into industry, transport, space technology, etc.

In those cases where the scanning field exceeds the dimensions of the observed object in both measurements \(X, Y\), and the speed of motion of the object is significantly less than the frame-sweep frequency, and, finally, when the resolving power of the scanning system \(\Delta X \cdot \Delta y\) satisfies the relation \(\Delta X \ll X^{m}\) obj., \(\Delta y \ll y^{m}\) obj., where \(X^{m}\) obj., \(y^{m}\) obj. are the minimum linear dimensions of the observed image, the use of the principles and apparatus of television systems raises no doubts. However, in various fields of technology—defectoscopy, radiolocation, production control—a number of problems have been posed concerning the display of information which, because of their specificity, cannot be solved with the aid of ordinary television systems.

One of these problems is the display on the screen of a cathode-ray tube of moving objects or media, direct observation of which is not possible because of a limited field of view (or for some other reasons, for example, the high cost of point sensors), not exceeding the dimensions of a single line. If, for generality, one also introduces the condition that the line-sweep frequency be commensurate with the speed of motion of the object, the problem becomes an independent one with numerous practical applications in various fields of science and technology.

To solve this problem, an electron-vacuum system has been developed in the USA [1], allowing television, radar, and infrared signals to be observed on a continuously moving tape placed inside a transparent tube. Its principle of operation is simple. An electron beam, brightness-modulated and synchronized with the sweep in a single-line scanning system, strikes the moving tape, causing luminescence of its coating (Fig. 1). The motion of the tape is synchronized with the speed of the observed object by means of electromagnetic couplings. The recorded information is erased by a source of infrared rays located beyond the viewing field. That is, the tube implements a method of recording data used in a linear scanning system onto photographic film moving at a speed

of the object perpendicular to the scanning line and characterized by “instantaneous manifestation.”

The main features of this method—the presence of short-term memory and rigid synchronization of the tape motion with the speed of the observed object—can be reproduced on an electronic model, eliminating any use of the expensive precision mechanical devices inherent in the electron-vacuum system considered.

Labels in the figure: focusing and deflecting system; observation field; source of infrared radiation; electron recording beam; electromagnetic clutches.

Fig. 1. Electron-vacuum display system.

mechanical devices inherent in the electron-vacuum system considered. Such a model was developed by the authors of this paper. Its brief description is given below (Fig. 2).

The initial information enters the device from a line-scanning system in analog form. The choice of the type and kind of sensor in the system is determined by the conditions of the particular problem.

By means of an analog-to-code converter, the input information is represented in discrete form, enters the digital register of the read-write unit, and is then written into the ferrite memory cube. The write address is determined by the position of the scanning system in the survey space; therefore there is a one-to-one correspondence between the scanning field and the matrix of the storage device.

To obtain on the screen of a cathode-ray tube a complete image of the information recorded and stored in the memory cube, its contents are read out continuously and, through a code-to-analog converter, fed to the input of the CRT.

The start of the line scan of the CRT is synchronized with the beginning of the reading of a line of the storage-device matrix; and, in order to obtain on the screen an image moving synchronously with the motion of the object, the frame scan of the CRT is started when the addresses of the readout line and the last recorded line coincide.

Let us explain this in more detail.

Recording of information about the object in the memory cube occurs synchronously with the motion of the scanning system and with the motion of the object itself, so that when the object stops, recording of information into the next line ceases. Switching of the write-address register is performed only when there is a signal from the motion sensor.

Thus, the last write line in the storage device proves to be synchronized with the motion of the object, and starting the frame scan of the cathode-ray tube from it makes it possible to obtain synchronous motion of the image with the object itself.

The frequency of reading information from the storage device is chosen from the condition of obtaining an image of acceptable quality and, in order to avoid flicker on the CRT screen, is taken to be on the order of 40–50 frames per second.

Fig. 2. Display schematic

Text appearing in the schematic:

• Light
• Motion sensor
• Coordinate system
• Motion sensor
• CRT
• Ramp generator \(X\)
• Ramp generator \(Y\)
• Data converter
• \(CShU\)
• Recorder / digit-code register
• \(CShU\)
• Forward code-to-dotted-code converter
• Inverting code-to-dotted-code converter
• \(CShU\)
• Dotted-code register \(Y\)
• Dotted-code register \(X\)
• Matching circuit
• Address register \(X_c\)
• Address register \(Y_c\)
• Address decoder \(X_c\)
• Address decoder \(Y_c\)
• Register for reading address \(Y_c\)
• Register for writing address \(Y_c\)
• Recording circuits
• Increase by one
• Shaping cube
• Character-recording block
• Data conversion
• Selection of information
• Analyzer circuit
• \(CShU\)

Coordination of the operation of all units of the device in time is carried out by the control unit.

In conclusion, we give the parameters of the manufactured version of the display system in Fig. 2. The rate of incoming input information is 18,000 bit/s; the capacity of the ferrite cube is 2048 6-digit binary numbers; the power consumption is 90 W; the dimensions are 50 × 40 × 30 cm.

REFERENCES

1. G. P. Katys. Automatic Scanning and Search in the Optical Range. Nauka Publishing House, Moscow, 1966.