SU377828A1 - DEVICE FOR TRANSFORMING THE IMAGE INTO ELECTRIC SIGNAL - Google Patents

Description

The invention relates to devices for automatically reading graphic information from paper media.

Devices are known for converting an image into an electrical signal with a matrix photoelectric image converter.

In these devices, serial, parallel, and parallel-parallel polling of matrix elements is possible. In a sequential polling, the signals of all the elements of the matrix are amplified by one amplifier. In parallel polling, the signals of each element of the matrix are amplified by individual amplifiers. In a serial-parallel survey, the signals of the elements of the matrix are amplified by several amplifiers, the number of which is less than the total number of elements in the matrix. With a large number of matrix elements, sequential polling devices have the most application.

The interrogation of elements of the known devices is carried out by connecting the rows of the matrix to the battery and the columns of the matrix to the load resistor, with one row and one column being connected at a time. The polling sequence of the elements is provided by row and column switches.

However, in known devices all elements of the matrix and switches must have

the same parameters. If the elements of the matrix and the switches have a variation of parameters, then with the same luminous flux, the output signals of the elements are different, so that with a certain combination of the variation of the parameters of the elements it is impossible to distinguish the image signal from the background signal. This disadvantage can be eliminated by the implementation of matrix elements and switches using the methods of integrated or film technology, but it is impossible to achieve satisfactory reproducibility.

In addition, the variation in parameters affects the operation of a matrix assembled on several substrates.

In order to improve the accuracy of the conversion, a matrix of supporting elements is introduced into the proposed device, similar to the matrix of photovoltaic cells, with the outputs of the matrix of supporting elements connected to the row switch and column switch, the output of which is connected to a load resistor and another amplifier input with adjustable gain.

In the drawing given the proposed device.

The proposed device contains a matrix / photovoltaic cells, an amplifier 2 with adjustable gain and a matrix of 3 reference elements (variable resistors), similar to the matrix /. The output of matrix 3 is connected

with the input of the gain control circuit of the amplifier 2 photonic array matrix signals. The number of elements in both matrices is the same, and they are synchronously polled by switches 4-7. The drawing shows the individual switches and batteries 8 and I, but they can be combined.

When interrogating matrix elements / photovoltaic cells simultaneously with connecting the photoresistor to the circuit (battery 8 - 4 rows switch - 5 columns switch - load resistor RH) in the matrix of 3 supporting elements, variable resistor Rij is connected to the circuit: battery 9 - 6 rows switch - 7 columns switch - load resistor,. The signal from the matrix of photovoltaic cells is removed from the RH and is fed to the input of amplifier 2, the signal from the matrix of supporting elements is removed from the RH., And is fed to the input of the gain control circuit of amplifier 2. The magnitude of the adjusting element (resistor) is selected at a setting such that RH sets the gain of amplifier 2 to the condition

K5. KstrokK columns - const,

where K is the gain of the amplifier;

S is the sensitivity of the photoelectric converter; Line - the transfer coefficient of the switch rows of the matrix of photovoltaic cells;

Columns - the transfer coefficient of the switch columns of the matrix of photovoltaic cells.

When this condition is fulfilled, the signal at the amplifier output has the same amplitude regardless of the scatter of the parameters of the photovoltage transducers and switches.

Each element of the matrix of the reference elements is adjusted similarly, depending on the sensitivity of the corresponding element of the matrix of photovoltaic cells.

Thus, in a sequential polling matrix photoconverter, more common and dummy discrete elements are used, and the integral or thin film transducers are assembled on several substrates.

The proposed device can be used in all information conversion devices when the sensor array has a variation of parameters, and after the amplifier it is necessary to have a signal that does not depend on this variation.

Subject invention

A device for converting an image into an electrical signal containing a matrix of photoconverters, the outputs of which are connected to a row switch and a column switch, to the output of which a load resistor is connected and one of the amplifier inputs with adjustable gain, characterized in that, in order to increase the conversion accuracy, the matrix of supporting elements, similar to the matrix of photovoltaic cells, with the outputs of the matrix of supporting elements connected to the row switch and column switch, the output cat This is connected to a pull-up resistor and another amplifier input with an adjustable gain.

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