SU1635285A1 - Device for line image correction - Google Patents

Description

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(21) 4680398/09 (22) 04/18/89 (46) 03/15/91. Bul Number 10

(71) Minsk Special Design Bureau of Automatic Lines

(72) V.I.Gulyov and S.M. Sheraisin (53) 621.397.2 (088.8)

(56) A de M. Fremont A.Fully Digital Teleclne System-BKSTSI, 1983, v. 65, Nh 5, p. 210-214. (54) DEVICE OF CORRECTION OF BAR IMAGES

(57) The invention relates to a technique for processing graphic and alphanumeric (bar) information in information retrieval systems and communication systems. The purpose of the invention is to improve the accuracy of correction of line images by improving noise immunity. The device contains delay elements 1 and 2, adder 3, inverter 4, threshold blocks 5, 6 and 7, elements HE 8, 9 and 10, elements 11 and 12 and element OR 13. The elements 1 and 2 of the delay and the adder 3 form the driver correction signal definition. The threshold unit 5 generates a two-level signal at the actuation level equal to half of the maximum signal span. The threshold blocks 6 and 7 form a two-level correction signal at the actuation level of + 3 -3 cty, respectively, where a is the rms interference level in the output signal of the adder 3. Elements NOT, AND OR 8-13 form a combinational digital circuit that completes the formation of a two-level corrected line image signal. 2 Il.

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The invention relates to a technique for processing graphic and alphanumeric (stroke) information in information retrieval systems, communication systems, etc.

The aim of the invention is to improve the noise immunity of the correction of line images.

Fig. 1 shows a structural electrical circuit of the device for correction of line images; Fig. 2 shows timing diagrams of signals explaining the operation of the device.

The device for correction of line images contains the first 1 and second 2 delay elements, the adder 3, the inverter 4, the first, second and third threshold blocks 5-7, the elements NOT 8-10, the first and second elements And 11 and 12 and the element OR 13.

The correction device line images works as follows.

The first 1 and second 2 delay elements and the adder 3 form a shaper correction signal (differential correction). The impulse characteristic of such a corrector is chosen symmetrical (the phase characteristic is linear), in particular, it has the following readings: -0.25; 0.5; -0.25; and the amplitude response is described by the expression sin W T / 2 (T is the delay time in one delay element).

The first threshold unit 5 generates a two-level signal at a trigger level equal to half the maximum signal sweep. The second and third threshold blocks 6 and 7 form a two-level correction signal at a response level of + 3 o and -3 o y, respectively (a is the rms interference level in the output signal of adder 3).

Elements 8-13 form a combinational digital circuit that completes the formation of a two-level corrected line image signal.

The image input signal Ui (Fig. 2a) is fed to delay element 1 and adder 3. From the output of delay element 1, signal 1) 2 (Fig. 2b) is fed to delay element 2, adder 3 and threshold unit 4. Output signal of adder 1) C (figv), representing a signal of differential correction, is supplied to the second threshold unit 6 and through the inverter 4 to the third threshold unit 7. Threshold blocks 6 and 7 form two level correction signals

respectively, for dark details on a light background Us (fig.2d) and light details on a dark field Ue (fig.2e). As a result, signals are formed: at the output of the threshold

block 5 is a two-level signal uncorrected 1) 4 (FIG. 2d), at the outputs of threshold blocks 6 and 7 there are two-level correction correction signals Us and Ue (figures 2d, e). These signals arrive at the combinational

a digital circuit that generates the resulting corrected signal and (FIG. 2g). Below is the truth table (state) of this scheme.

Then the analytical form of the logical

functions (in perfect disjunctive normal form) has the form (minimal form)

Uv-UoUsUevU-lUsUe.

To implement it, output signals

threshold blocks 5, 6, and 7 are fed to three elements, HE 8-10, first and second elements AND 11 and 12, and element OR 13, at the output of which a corrected two-level line image signal is generated.

Claims (1)

The invention of the device correction of line images, containing the first delay element, the output of which is connected to the input The first threshold unit and with the input of the second delay element, and the inputs of the first and second delay elements and the output of the second delay element are connected to the corresponding inputs of the adder, so that, in order to improve the accuracy of correction of line images by improving noise immunity, the inverter, the second and third threshold blocks, the elements NOT, AND and OR, the output of the adder is connected to the input of the second threshold unit and through an inverter with the input of the third threshold unit, the output of which is connected to one of the inputs of the first element AND, to the other two inputs of which the outputs of the first threshold unit are connected via the corresponding element NOT and the output of the second threshold unit through the corresponding element NOT, the output of which is connected to 0 to the corresponding input of the second element AND, to the other two inputs of which the output of the first threshold unit is connected directly and the output of the third threshold unit through the corresponding element NOT, and the outputs of the first and second elements AND are connected to the inputs of the OR element.