JPS6243972A - Binarization circuit for picture signal in facsimile equipment - Google Patents

Abstract

PURPOSE:To obtain a sharp binarization signal by providing an original reading circuit, a line memory circuit, an average density calculating circuit, the first delay circuit, an emphasis circuit, the second delay circuit and a threshold circuit. CONSTITUTION:An original reading circuit 1 optically scans an original surface and photoelectrically converts a reflected light, converts the photoelectrically converted analog picture signal into a digital signal to output a digital picture signal 11. A line memory circuit 2 outputs an one line delay picture signal 12 and a two line delay picture signal 13. An average density (calculating) circuit 3 inputs the picture signal 11 and the delay signals 12, 13, outputs an average density signal 14 of three lines. A delay circuit 4 inputs a delay signal 12 and outputs a delay picture signal 17 delayed by several bits so as to make the signal 12 a center of an average density area. A delay circuit 5 corrects the average density signal by the delay part of an operation by an emphasis circuit 6 and an average density signal 15 and an emphasis circuit output 20 are inputted to a threshold circuit 7 and a binarization signal 16 is outputted. Thereby, a deterioration of the picture signal due to an ability or the like of a reading element can be corrected and a sharp binarization signal output can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a one-car open code binarization circuit, and in particular, to a one-car open code binary conversion circuit.
The present invention relates to binarization processing of a document reading image signal of a device.

Conventional technology Conventional facsimile machines can read 1M documents.
) Nine analog picture signals are converted into digital picture signals, and the thread VW level for a pixel to be binarized is determined based on the relationship with the average density around the pixel, and binarization is performed.

The problem that the invention aims to solve However, the conventional binarization circuit described above.

To compare the digital pixel signal itself read by the reading 9 circuit and the average density of the surrounding area.

The resolution of the reading element affects the binarization.

Those with poor resolution had defects such as poor peeling and inability to obtain sharp images.

The present invention has been made in order to eliminate the above-mentioned drawbacks inherent in the conventional technology, and therefore, an object of the present invention is to correct the deterioration of the image signal due to the ability of the reading element, etc., thereby achieving a sharp binary aperture. An object of the present invention is to provide a novel image signal binarization circuit that makes it possible to obtain a signal output.

Means for Solving the Problems In order to achieve the above objects, the image signal binarization circuit of the facsimile machine according to the present invention converts an analog image signal obtained by reading a document into an N-bit digital pixel signal. A document reading circuit, a line memory circuit that can store several lines of digital pixels from the document reading circuit, an average density calculation circuit that outputs the average density of an arbitrary area for the digital pixels, and h2 value conversion [ , a first delay circuit that delays a digital pixel so that the pixel to be measured is in the center of the averaged area, and N=A+k (A-B) for the delayed digital pixel. N: Emphasis circuit output A: Attention - yg (digital image 1g) B: To average density: The output from the emphasis circuit that calculates the emphasis coefficient and the average density calculation circuit are delayed by a second delay circuit, and the output from the emphasis circuit is compared [ 7 and a threshold circuit that performs binarization.

Practical Example Next, a preferred example of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the present invention.

In the figure, a document reading circuit 111. Il [K area is optically scanned and the reflected light is photoelectrically converted] 7, converts the photoelectrically converted analog image signal into digital and outputs digital image signal 11 (for example, 4-bit image signal), line memory circuit 2 is capable of storing two lines one by one, and outputs an 1-line delayed image signal 12 and a 2-line delayed image signal 13, respectively. The average density (calculation) circuit 3 has one line delay signal 11. and the 2-line delayed signal 13 are input, and the 3-line average density signal @1 is input.
Outputs 4.

In addition, the delay circuit 4 inputs the 1-line delayed signal 12 and produces a delayed image signal which is delayed by several bits so as to be in the center of the average density range (the range of the image signal averaged inside the average density circuit 3). Outputs 17.

Enhancement circuit 6 calculates N=A+k(A-B) N: Enhancement output 20 White MAX≦N≦Black MAXA: Delayed image signal 17 B: Average density circuit 14 To: Enhancement coefficient (arbitrary value, variable) It is a circuit. The kO value is arbitrary.

Since it is variable, while looking at the 1 image quality and the binarization code 16,
The optimal value can be determined.

The emphasis circuit 6 includes a delayed image signal 17 and an average density signal 14.
is input, and the subtraction circuit 8 calculates (A-B) in the above-mentioned equation. The subtraction output 18 of the subtraction circuit 8 is input to the multiplication circuit 9, where the calculation of .multidot.(A-B) is performed. Multiplier circuit 90 multiplier output 19 and delay image signal 17 of delay circuit 4
are respectively input to the adder circuit 10.

The calculation A-1-k (A-B) is performed. The delay circuit 5 has a function of correcting the delay in calculation by the emphasizing circuit 6 for the average density signal, and outputs the delayed average density signal 15.
20 emphasis circuit outputs are input to a threshold circuit 7, where a threshold level is determined, and a binarized signal 16 is outputted by a threshold circuit 7 which binarizes the digital pixel.

As described in detail, according to the present invention, when an analog signal obtained by reading a document is to be binarized, one image information signal itself is not compared with the average density of the surrounding area, but an emphasis circuit is used. By comparing the emphasized pixel signal and the average density to determine the threshold, it is possible to correct the deterioration of the image signal due to the equal pressure of the reading element, and a sharp binary decoding output can be obtained. This effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one example of the present invention. 1... Original reading circuit, 2... Line memory circuit. 3... Average density circuit, 4... Delay circuit, 5... Delay circuit.

Claims (1)

[Claims] In a facsimile scanning device that reads document information by optically scanning the document surface, condensing transmitted or reflected light from the document surface, and photoelectrically converting it, the photoelectrically converted analog image signal is converted into a bit-parallel digital signal. An original reading circuit that outputs an original, a line memory circuit that can store several lines of digital pixels output from the original reading circuit, and an average density calculation circuit that outputs an average density of a predetermined area for the digital pixels. , a first delay circuit that delays a digital pixel so that the pixel to be binarized comes to the center of the averaged area, and a digital pixel delayed by the first delay circuit and a signal from the average density calculation circuit. an emphasis circuit that inputs the average density output, performs emphasis calculation, and outputs an emphasized digital signal, and a second delay circuit that delays the output from the average density calculation circuit by an amount delayed by the emphasis calculation circuit; An image signal binarization circuit for a facsimile machine, comprising a threshold circuit that binarizes a digital pixel using the output of the second delay circuit and the output from the emphasis circuit.