JP3112988B2 - Digital image processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading process, and more particularly to a digital image processing apparatus for performing image processing on image data read by a scanner.

[0002]

2. Description of the Related Art When a document having a relatively high light transmittance is read by a scanner, an image on the back side may be read. For example, when copying a document having images on both sides with a copying machine, a so-called show-through phenomenon may occur in which if the document is thin, the contents on the back side of the surface to be copied are lightly reflected.

In order to prevent this, it is known that a gamma curve is adjusted so that a low density portion is not output.

[0004]

However, according to the method of adjusting the gamma curve, in addition to the prevention of show-through phenomena, there is a problem that a low-density portion is not output even in an image of a surface to be originally copied.

SUMMARY OF THE INVENTION It is an object of the present invention to extract an image of a surface to be originally read as it is and to prevent show-through.

[0006]

According to the present invention, there is provided a storage means (2) for storing image data of a read original surface.
7); means (21, 283, 285) for horizontally inverting the read image data on the back side of the original; and multiplying the image data, which has been inverted left and right, by a weighting factor (k) and reading it out from the storage means (27). Image processing means (21, 28, 284) for subtracting from the image data of the original surface. Symbols in parentheses indicate corresponding elements or items in the embodiment shown in the drawings and described later.

In a preferred embodiment, input data display means (61, 62) for displaying read image data;
And output data display means (61, 62) for displaying the image data processed by the image processing means (21, 28, 284).

[0008]

According to this, the image processing means (21, 28, 2)
84) reads out the read image data of the front side of the document from the storage means (27), and subtracts the image data obtained by inverting the read side image data of the back side of the document from this image data and multiplying by the weighting factor (k). Unnecessary backside images are canceled, and the image of the side that the operator originally wants to read (the front side of the document) is extracted without any show-through.

According to a preferred embodiment [0009] Also, the input data display means for displaying the image data read (61,6
2) and output data display means (61, 62) for displaying the image data processed by the image processing means (21, 28, 284), so that the operator can check the overall image while maintaining a good balance. The weight coefficient can be easily set. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0010]

Embodiment (First Embodiment) FIG. 1 shows an embodiment of the present invention. This embodiment shows an electric system of a digital copying machine.

[0011] The image input unit 1, Ri Oh a scanner, the image output unit 3 is Ru Oh laser printer. In the scanner, the image of the document by the irradiation of the fluorescent lamp is irradiated on the CCD of the image reading plate through a mirror and a lens, where it is scanned and converted into an electric signal. The electric signal obtained by the CCD is an analog value, but is converted into a digital value by an AD converter.

[0012] The converted image data is input to the image processing unit 2. The image processing unit 2 performs various image processing, for example, image editing. The image data subjected to the predetermined processing is sent to the printer.

The image processing unit 2 controls and processes the system, and plays a central role in a CPU 21, a system bus 22 for connecting the CPU 21, a ROM 23, a RAM 24, interfaces (I / F) 25, 26, 28 and a page memory 27.
And so on. The ROM 23 stores programs and data required by the CPU 21. RAM 24
Is a working memory temporarily used by the CPU 21. A page memory 27 for storing image data is connected to the system bus 22 via the interface 26 of the image input unit 1 and the interface 28 of the image output unit 3 via the interface 28, respectively. In addition, a display input unit 4 for displaying or inputting various information is connected to the system bus 22 via an interface 25. The interface 26 and the interface 28 are connected to the page memory 27 without passing through the system bus 22, and are configured to input and output image data at high speed.

[0014] FIG. 2 shows a schematic configuration of Intafe over scan 28. Intafe over scan 28 line buffer 281, a line buffer 282, a built-in address counter 283 or the like, after the left and right inversion (mirror) processing image data inverting circuit (arithmetic circuit) 285, a concentration in the multiplication circuit (arithmetic circuit) 284 A process of multiplying by the corresponding weight coefficient (k) and subtracting from the image data before the left / right inversion (mirror) process is performed at the time of printer output.

In the printer, a semiconductor laser (laser diode : LD) is modulated based on the transmitted data, and the modulated laser light is irradiated onto a photosensitive drum via a polygon motor rotating at a constant speed. This forms an electrostatic latent image on the drum. The electrostatic latent image on the drum is developed by a developing unit, and the visualized image is transferred to a transfer drum. Then, after being transferred onto the sheet from the transfer drum, the sheet is fixed and discharged.

FIG. 3 shows a part of the appearance of the display input unit 4 provided in the digital copying machine. Each key and display will be described. Sign-41 print start key for entering the copy start instruction, sign-42 mode clear key for clearing the respective modes, reference numeral 43 is a clear / stop key for inputting an instruction such as a clear and copy interrupt copy set number <br Reference numeral 44 denotes a numeric keypad for inputting the number of copies and the like, reference numeral 45 denotes a seven-segment display of the number of originals set, and reference numeral 46 denotes a seven-segment display of the number of copies processed. Reference numeral 47 denotes a show-through prevention mode key for designating show-through prevention processing according to the present invention. The number of weighting factors (corresponding to the density) to process (cancel) the image on the back side is specified by the numeric keypad 44. Note that a new setting key may be provided. Various other keys and indicators such as a density adjustment key , a scaling key , and a double-sided copy key are provided on the operation display unit 4, but illustration and description thereof are omitted here.

Hereinafter, the show-through prevention mode of this embodiment will be described. FIG. 4 shows a flowchart of the show-through prevention processing executed by the CPU 21. In this mode, after the operator presses the show-through prevention mode key 47 on the display input unit 4 and inputs the weight coefficient k with the ten keys 44, the start key 4
Pressing 1 executes it. Note that the operator sets the side of the original having images on both sides that is to be copied ( expressed as the front side) at a position where the scanner reads the original.
In this process, first, the input weight coefficient k is read ,
Set to register k (Step 1: In the following parentheses, the word “step” is omitted and only the step number is written.
Enter ).

Then, the front side of the document is scanned by a scanner (2), and the read image signal of the front side is stored in a page memory 27.
(3). Next, the operator sets the back surface of the document at the reading position with the scanner, and scans the back surface of the document with the scanner (4). The read back image signal is subjected to left / right inversion (mirror) processing by an arithmetic circuit of an address counter 283, an inversion circuit 285, and a multiplication circuit 284 shown in FIG. 2 (5), and the left / right inverted signal is multiplied by a weight coefficient k. (6). Next, the image signal of the front surface is read out from the page memory 27 (7), and the weight coefficient k is obtained from this signal.
The left and right inverted signals after the multiplication are combined so as to be subtracted (8). Then, printing is started with the combined signal (9).

By this processing, the image on the back side is canceled and the show-through is eliminated.

[0020] Example of the Second Embodiment This was a display input unit 4 of the first embodiment flat large LCD display 62 as shown in FIG. 5 and (may be CRT) and a keyboard 61, a display Figure 2 shows a system with The outline of the configuration of the electric system is the same as that of the first embodiment. While checking the image after the show-through prevention processing on this display 62, the weight coefficient of the processing is changed to determine the optimum coefficient.

FIG. 6 shows a third embodiment which is different from the first embodiment shown in FIG.
4 shows a flowchart of show-through prevention processing according to the embodiment. Note that the same processes as those in the first embodiment are denoted by the same step numbers, and description thereof is omitted.

In this processing, when an operator wants to display an image for confirmation or the like after reading the surface to be copied (the front side of the original) with a scanner and after performing show-through prevention processing, the image can be displayed on the display 62. , And then the weighting factor can be reset (2a to 2a).
b and 8a-8c).

As a result, even if a problem occurs when processing is performed with uniform coefficients, a well-balanced weight coefficient can be easily set while viewing the entire image. In addition, in the system, if the page memory has two screens, the work can be efficiently performed, but if the work is performed while replacing the original, the work can be performed without the two screens.

[0024]

As described above, according to the invention of the present application, an unnecessary backside image is canceled out, and an image of the side (the front side of the original) that the operator originally wants to read is extracted without any show-through.

[0025] According to a preferred embodiment, operator can easily set a good weighting factor balanced while checking the entire image.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an interface 28 shown in FIG.

FIG. 3 is a plan view schematically showing a part of a display input unit 4 shown in FIG.

FIG. 4 is a flowchart showing a control operation of show-through prevention processing of the first embodiment by the CPU 21 shown in FIG. 1;

FIG. 5 is an external perspective view showing a display input unit 4 shown in a second embodiment.

FIG. 6 is a flowchart showing a control operation of show-through prevention processing of the second embodiment by the CPU 21 shown in FIG. 1;

[Explanation of symbols]

1: image input unit 2: the image processing unit 3: image output unit 4: the display input section 21: CPU (means for horizontally inverted, the image processing hand stage) 22: System bus 23: ROM 24: RAM 25: interface 26: Interface 27: page memory (storage means) 28: interface (image processing means) 47: show-through prevention mode key 61: keyboard (input data display means, output data display means) 62: liquid crystal display (input data display means, output data display) Means) 281: Line buffer 282: Line buffer 283: Address counter (means for inverting left and right) 284: Multiplying circuit (image processing means) 285: Inverting circuit (means for inverting left and right)

Claims (2)

(57) [Claims] A storage means for storing the read image data of the front side of the document; a means for horizontally inverting the read image data of the back side of the document; Image processing means for subtracting from the image data of the document surface read from the means. 2. The digital device according to claim 1, further comprising: input data display means for displaying the read image data; and output data display means for displaying the image data processed by the image processing means. Image processing device.