JPS63228879A - Image reduction system for electronic blackboard - Google Patents

Abstract

PURPOSE:To obtain a printed image in reduce size or standard size by scanning the board surface with a double density in both scanning directions, taking the OR of read signals in the main scanning direction at every specified piece of dots, and executing a subscanning by switching its density to a specified value. CONSTITUTION:The dot density in the main scanning direction of a line sensor 13 and the rate of clock signals supplied to a driving circuit 14 are made double at fast as a standard case, also, output image signals from a binary conversion circuit 15 are in a density double as much as the standard case in the main scanning direction. A 3/2-dot OR circuit 20 takes the OR of an output signal from the circuit 15 at every three or two dots, and outputs it as a one-dot signal. A control circuit 21 controls a mobile device 22 to change the moving speed of the sensor 13 to be 1.5 times as fast as the standard speed or to the standard speed. In such a case, the one-line-read time of the sensor provided by the driving circuit 14 is the standard. Thereby, the area of an image is made approximately a half of standard size or the standard size.

Description

[Detailed Description of the Invention] [Summary] When printing an image displayed on the board surface of an electronic whiteboard, the board surface is scanned at twice the density in the main scanning direction and in the sub-scanning direction to print the image. The image signals obtained by reading are read in the main scanning direction and printed by performing sub-scanning, thereby obtaining a printed image whose area is reduced to approximately 1/2 or a standard-sized printed image.

[Industrial application field]

The present invention relates to an image reduction method in image reading processing of an electronic blackboard, and particularly to a printing area of a standard size or about 1
This invention relates to an image reduction method for an electronic blackboard that can be reduced to a size of 72.

Some electronic blackboards have a function of reading images of characters, figures, etc. written or pasted on the board surface and printing them on paper. FIG. 4 explains the reading of the board surface of an electronic blackboard, in which the image on the sheet surface 1 forming the blackboard surface is read by the line sensor 2 in a direction perpendicular to the direction of the sheet 1 in the main scanning direction; It is shown that the plate surface is read by scanning in two directions: a sub-scanning direction in which reading is performed as the sheet 1 or line sensor 2 moves in a direction perpendicular to this direction.

When reading and printing such an image, it is generally used to read the pixels (dots) that form the image as they are and print and display them on a predetermined paper surface in a specified size (standard size). However, for purposes such as saving paper space, an @image reduction method is being considered in which the image is printed smaller than the printing area of Tsuho.

FIG. 5 explains the image reduction method, and shows (a)
indicates an image on the board surface, and it is understood that image 3 was displayed on sheet 1. (b) shows a printed image in the case of standard size, and shows a printed image when no reduction processing is performed. (C) shows a printed image when reduced printing is performed, and shows that an image is printed that is smaller than the printed image in the case of standard size.

When performing such reduced printing, the printing area is halved and two screens are printed on one standard sheet of paper, or the printing paper size is halved (for example, A4 size - A5 size). It is desired to be able to reduce the amount of printing paper used.

[Conventional technology]

As a conventional image reduction method for electronic whiteboards, a method is known in which the vertical and horizontal directions of the screen are each reduced to 1/2, and the printing area is therefore reduced to 1/4.

This can be easily realized, for example, by reading pixels every other dot in the horizontal direction and reading every other scanning line in the vertical direction.

FIG. 6 shows a conventional image reduction method, in which the image displayed on the plate surface 11 is formed on the line sensor 13 via the lens 12. The drive circuit 14 drives the line sensor 13 in the main scanning direction according to the clock signal to output an image signal line by line.

A binary conversion circuit 15 converts the output signal of the line sensor 13 into a binary value dot by dot in accordance with a clock signal. The dot thinning circuit 16 generates a signal by thinning out the output signal of the binary conversion circuit 15 every other dot. The output signal of the binary conversion circuit 15 is generated line by line in the main scanning direction according to the sub-scanning, but the line thinning circuit 17 thins out the signal every other line and generates an output signal. The processing circuit 18 processes the output of the line thinning circuit 17 and generates a printing signal, and the printer 19 performs a printing operation based on this signal, thereby reducing the output by 1/2 in each of the main scanning direction and the sub-scanning direction.
The reduced image is printed.

[Problem that the invention seeks to solve]

In the conventional image reduction method described above, the printing area is reduced to 1/4, which causes the printed image to be too small and difficult to see, but no improvement plan has been proposed to date.

(Means for Solving the Problems) The present invention attempts to solve the problems of the prior art, and has the basic configuration shown in FIG. In an electronic whiteboard that reads line by line in the main scanning direction and performs sub-scanning according to the movement of the board surface or line sensor, and binarizes and prints the obtained image, the double-density reading means 101 and 3/ 2 dot OR means 102 and sub-scanning density conversion means 103;
By printing with the output of the /2 dot OR means 102, a printed image whose area is reduced to approximately 1/2 or a standard size printed image is obtained.

The double density reading means 101 scans the board surface in the main scanning direction at double density to read an image.

The 3/2 dot OR means 102 performs an OR operation on the smear removal signal in the main scanning direction every three dots or every two dots and outputs the result.

The sub-scanning density conversion means 103 converts the sub-scanning density to 1/1.
The sub-scanning is performed by switching to 5 or 1.

[For production]

Image reduction in the method of the present invention is performed as follows.

If the image is not reduced, two dots are printed in the main scanning direction when printing from an image obtained by reading the board surface at twice the density in the main scanning direction compared to the standard case. By ORing each time and setting the scanning in the sub-scanning direction to the standard moving speed and reading time, a standard-sized print image is obtained.

When reducing an image, the reading of the board surface in the main scanning direction is similarly done at twice the density, and when printing, OR's every 3 dots in the main scanning direction and scans in the sub scanning direction. When the reading time for one line is set as the standard, the moving speed is set to 1.5 times, and when the moving speed is set as the standard, the reading time for one line is printed at 1.5 times, so the printed image is the standard size. On the other hand, it is 1/1 in both vertical and horizontal directions.
It is reduced to 5.

The present invention realizes such a screen reduction method, and as shown in FIG. 1, the double density reading means 101 scans the board surface at twice the density in the main scanning direction to generate an image. The read signal in the main scanning direction is divided into 3 by the 3/2 dot OR means 102 for the image signal obtained by reading.
In addition to calculating the OR for every dot or two dots and outputting the result, the sub-scanning density converting means 103 changes the sub-scanning density to 1/1.5 or 1, and converts the sub-scanning density to 3/2 dot OR means 1.
By printing using the output signal 02, a printed image whose area is reduced to approximately 1/2 or a standard size printed image can be obtained.

【Example〕

FIG. 2 is a block diagram showing one embodiment of the present invention. In this figure, the same parts as in FIG. 6 are designated by the same numbers, and 20 is a 3/2 dot-OR circuit, 21 is a control circuit, and 22 is a moving device.

However, in this case, the dot density of the line sensor 13 is 2 times that of the standard case in the main scanning direction, and the drive circuit 14
The clock signal speed given to the is also 2 compared to the standard case.
The image signal is read out at twice the standard density in the main scanning direction, and therefore the image signal output from the binary conversion circuit 15 also has twice the standard density in the main scanning direction. ing.

The 3/2 dot OR circuit 20 ORs the double dot density main scanning direction signal output from the binary conversion circuit 15 every 3 dots or every 2 dots and outputs it as a 1 dot signal. , compress by 1/3 or 1/2. Therefore, the number of dots in the signal in the main scanning direction after compression is 2/3=1/1.5 in the case of 1/3, and 2/2,0001 in the case of 1/2.

The control circuit 21 controls the moving device n to switch the moving speed of the sheet 1 or the line sensor 2 to 1.5 times the standard speed or the standard speed. However, in this case, the time required for reading one line of the line sensor by the drive circuit 14 is standard.

The processing circuit 18 processes the output of the 3/2 dot OR circuit 20 to generate a printing signal, and the printer 19 performs a printing operation based on this signal.

In this case, the printed image is 1/3, the number of dots in the main scanning direction is 1/1.5, and the number of lines in the sub-scanning direction is 1/1.5, so the printing area is standard. 1/1.5 of size x 1/1.5 = 1/2.25
= 1/2, and the purpose of reducing the printing area to about 1/2 is achieved. In addition, in the case of 1/2, the printing area is the standard size.

Note that instead of performing control to switch the moving speed of the sheet 1 or the line sensor 2, the moving speed is kept constant and the drive circuit 14 is controlled to change the reading time of the line sensor 13 to 1.5 times the standard or to the standard. Even if the control is performed, the density in the sub-scanning direction can be similarly converted to 1/1.5 or 1, and the same effect can be obtained.

FIG. 3 shows a specific example of the circuit configuration of the 3/2 dot-OR circuit 20 in the embodiment shown in FIG.

In FIG. 3, FFI and FF2 are JK flip-flops, which together with a NAND circuit G1 form a ternary/binary output counter circuit, and a ternary/binary switching signal 1IIZllQ.
”, it operates as a ternary counter or a binary counter.The output of this circuit passes through a NAND circuit G2 and is output as a clock obtained by dividing the double speed clock by 1/3 or 1/2. .

On the other hand, FF3. FF4 is a flip-flop and forms a 3/2 dot OR circuit together with OR circuit G3. When the ternary/binary switching signal is "1", the signal in the main scanning direction with double dot density from the binary conversion circuit 15 and the F
F3. Outputs a signal obtained by ORing with the signal delayed by FF4, and when the ternary/binary switching signal is "0",
A signal obtained by ORing the double dot density main scanning direction signal of the binary conversion circuit 15 and a signal delayed by the FF 3 is output.

When performing image reduction operation, set 11 to the ternary/binary switching signal.
111, the ternary/binary output counter circuit counts the double speed clock signal and produces an output every three clocks. The FF5 reads the output of the 3/2 dot OR circuit using the output of the ternary/binary output counter circuit as a clock and generates an output, but in this case, the 3/2 dot OR circuit is in the state of ORing 3 dots. Therefore, the output of the FF 5 is a signal obtained by ORing every three dots in the main scanning direction, and a signal compressed to 1/1.5 of the standard size is obtained.

When the image reduction operation is not performed, "0" is given to the ternary/binary switching signal, and the ternary/binary output count circuit counts the double speed clock signal and outputs it every two clocks. Occur. In this case, the 3/2 dot OR circuit is in a state of ORing 2 dots, and therefore the output of FF5 is a signal obtained by ORing every 2 dots in the main scanning direction.
Equivalent to the signal for standard size.

Note that when printing two images on one screen whose area has been reduced to about 1/2, the output signal of the circuit shown in Figure 3 should be further converted vertically and horizontally. There is a need to.

〔Effect of the invention〕

As explained above, according to the image reduction method of the present invention, reading is performed in the main scanning direction at twice the standard dot density, and when the image is not reduced, the density in the main scanning direction is reduced to 1/2. In addition, when printing a standard size image by setting the moving speed and reading time in the sub-scanning direction as standard, and reducing the image, the density in the main scanning direction is reduced to 1/3, and Printing is performed with the density in the sub-scanning direction set to 1/1.5, so the density in the vertical and horizontal directions is set to 1/1.5.
1.5, it becomes possible to print after reducing the area to about 1/2.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing a specific circuit configuration example of a 3/2 dot-OR circuit, and FIG. is a diagram explaining how to read the board surface on an electronic blackboard, FIG. 5 is a diagram explaining an image reduction method, and FIG. 6 is a diagram explaining an image reduction method in a conventional electronic blackboard. Control circuit 22-・Movement device

Claims (1)

[Claims] The image displayed on the board surface is read line by line in the main scanning direction by a line sensor, and the image obtained by performing sub-scanning according to the movement of the board surface or line sensor is converted into a binary image. In an electronic blackboard that is printed as a digital whiteboard, a double density reading means (101) reads an image by scanning the board surface at twice the density in the main scanning direction, and a reading signal in the main scanning direction is read in 3 dots or 2 dots. 3/2 dot OR means (102) for calculating an OR value for each time and outputting the result, and sub-scanning speed converting means (103) for performing sub-scanning by switching the sub-scanning density to 1/1.5 or 1, Image reduction in an electronic blackboard, characterized in that a printed image whose area is reduced to about 1/2 or a standard size printed image is obtained by printing with the output of the 3/2 dot OR means (102). method.