JPS5936479A - Picture processor - Google Patents

Abstract

PURPOSE:To obtain a picture signal in a state of the detailed information of an original picture is held as it is, and noise signal component having a narrow area is suppressed, by processing arithmetically an electric signal of light passing through a slit having a through-hole of a suitable size. CONSTITUTION:A slit 15 having a through-hole having a size resoluting normally a picture on an original 11, a slit 16 having a through-hole having a larger through-hole than that of the slit 15, and a slit 17 having a through-hole the same size as that of the slit 16 and formed with a light shield section having an outer diameter the same size as that of the slit 15, are provided on the original 11 so that each through-hole has the same center. The light passing through the through-hole of the slits 15-17 is converted into an electric signal at photoelectric converters 18-20. Outputs of the photoelectric converters 18- 20 are processed at operational amplifiers 24, 25 via amplifiers 21-23 and a picture signal suppressing the noise signal component from the operational amplifier 25 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image processing device used in an image scanning and recording device that scans an input original to obtain an image signal and uses the image signal to reproduce a recorded image. It is something.

Conventional configuration and problems The image data obtained by scanning an original image like a facsimile contains various noise components. For example, there are one-dimensional noise generated in a photoelectric conversion system, and two-dimensional noise contained in the document itself.

The latter noise is information other than the information that the observer needs from the original image, and may include dust or scratches on the original, stains or faded parts of old photographs, or roughness due to the paper quality of the original. Among these types of noise, -dimensional low frequency component noise and noise having a two-dimensional wide area cannot be removed without performing complex processing such as pattern identification.

Noise removal, which has been commonly performed in the past, targets noise with high frequency components other than those mentioned above and noise with a narrow area, and performs operations to reduce these.At the same time, the details of the original image are This results in the loss of even the most detailed information about the original image. For example, suppose that there is an image on a document in which small noise stands out in the background of a figure wearing a woolen sweater. If conventional noise removal is performed on the original image data to remove this background noise, the fine fiber image information of the yarn will not be lost at the same time, and the warm feel of the yarn in the original image will change to a cold one.

FIG. 1 is a block diagram of a conventional image processing device.
The figure is a waveform diagram for explaining the operation.

In FIG. 1, an image of a document 1 is formed on the surface of a slit 3 through a lens 2. The light passing through the slit 3 is converted into an electrical signal by a photoelectric converter 4. This electrical signal is passed through a low-pass filter 5 to produce a signal in which high-frequency component noise mainly generated by the photoelectric converter 4 is reduced.

Now, 81-82 of manuscript 1 (hatched area is black) shown in Figure 2.
When scanning between n1. Assume that there is n2 noise. When the through hole of the slit 3 is large enough to resolve the image of the original 1 into regular resolution, the scanned signal waveform becomes as shown in A, and there is noise n1. It appears as a signal with an amplitude larger than n2 by δ, and noise becomes noticeable. In order to reduce this noise signal, the through hole of slit 3 is made larger and the image of document 1 is resolved at scanning points larger than the noise points nl and n2, but the waveform at this time becomes mouth-like. , noise point n1. The amplitude of the signal component for r12 becomes smaller, but at the same time, the rise and fall of the image signal become gentler, and the details of the image are lost.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems.
It is an object of the present invention to provide an image processing device capable of reducing isolated noise components in a narrow area of a document and preserving the details of image information required by the document as is.

Structure of the Invention The present invention provides a first . Second. and a third slit, a photoelectric conversion means for converting the light passing through each through hole into an electrical signal, and a photoelectric conversion means for converting the light that has passed through the through hole of the first slit into an electric signal that has passed through the through hole of the second slit. The first step is to subtract the electrical signal of light.
and a second subtraction means for obtaining an image signal by subtracting the electrical signal obtained by the first subtraction means from the electrical signal of the light passing through the through hole of the third slit, The through hole of the slit is made large enough to properly decompose the image on the document, the through hole of the first slit is made larger than the through hole of the third slit, and a light shielding part is provided inside the through hole of the second slit. By adopting a configuration in which the first subtraction means detects a noise point having a narrow area on the document, the second subtraction means reduces the amplitude of the sting signal and extracts details of necessary image information. is obtained at the same level as the regular image resolution.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of the image processing apparatus of the present invention, and FIG. 4 is a waveform diagram for explaining its operation. In FIG. 3, the image on the document t is captured by the lens 12.
3 surin through half mirror 13, 14) 15,
The image is formed on the plane of 16.17. Surin) 15, 16
．． The optical images at the centers of the through holes 17 are made to perfectly match each other on the image of the original 11. The size of the through hole of the slit 15 is the size that allows the image of the original 11 to be resolved into a regular resolution, and the size of the through hole of the slit 16 is the size of the slit 1.
It is larger than the through hole of No.5. A light shielding part is provided in the center of the through hole of the slit 17 to prevent light from passing through.
For example, the outer diameter of the light passing portion is the same as the hole in the slit 16, and the inner diameter of the light passing portion is the same as the hole in the slit 16.
Make it bigger than that. The light passing through the slits 15, 16, and 17 is transmitted to photoelectric converters 18, 19, and 20, respectively.
After being converted into an electrical signal at
Reduces high frequency noise such as that generated by At the same time, here, the output signal amplitudes of the all-white and all-black portions of the document 11 are normalized to be at the same level. 24 is an operational amplifier, and a low pass filter 2
The signal passed through the low-pass filter 23 is subtracted from the signal passed through the low-pass filter 23. 25 is also an operational amplifier, which subtracts the signal obtained by the operational amplifier 24 from the signal that has passed through the low-pass filter 21, and outputs an image signal for obtaining a reproduced image.

Next, the operation of this embodiment will be explained using the waveform diagram of FIG. 4. Now, 83- of the original image a (hatched area is black) shown in FIG.
When scanning between n3. Assume that there is n4 noise. Low pass filter 21 at that time
The output signal waveform of the low-pass filter 22 is as shown in b, and the output signal waveform of the low-pass filter 22 is as shown in the solid line C. In short, the output signal waveform of the low-pass filter 23 is of the waveform C,
Noise n3. The part n4 looks like a dotted line. This is because the part inside the through hole of the slit 17 that does not allow light to pass through is the noise point n3. This is the part that overlaps with n4. Here, from the output signal of the low-pass filter 22, the low-pass filter 23
When the output signal of is subtracted by the operational amplifier 24, the noise point n3
．． n4 signal can be detected. As shown in waveform d, after adjusting the output amplitude of the noise signal with the operational amplifier 24, this noise signal is subtracted from the output signal waveform of the low-pass filter 21 with the operational amplifier 25. As shown in the waveform e, the noise signal is An image signal waveform with a reduced signal amplitude is obtained. The details of this image signal are obtained to the same degree as the normal image resolution of the waveform.

As described above, according to this embodiment, the slit 16 has a through hole large enough to properly decompose the image on the original 11, the slit 16 has a through hole larger than the through hole of the slit 16, and the slit 15 has a through hole that is larger than the through hole of the slit 15. A light-shielding portion having the same outer diameter as the hole is formed inside, and a slit 17 having a through-hole of the same size as the through-hole of the slit 16 is formed so that each through-hole is connected to the document 1.
The electric signal of the light passing through the through hole of the slit 19 is located on the slit 1 so as to have the same center on the slit 2.
The electrical signal of the light passing through the slit 21 is subtracted by the operational amplifier 24, and the output signal of the operational amplifier 24C is subtracted by the operational amplifier 25 from the electrical signal of the light passing through the slit 21.
The operational amplifier 25 obtains an image signal with suppressed noise signal components having a narrow area while preserving detailed information of the original image as is.

In this embodiment, the outer diameter of the through hole of the slit 17 was made the same as the outer diameter of the through hole of the slit 16, and the outer diameter of the light shielding part was made the same as the outside diameter of the through hole of the slit 15. is not limited to this, and the through hole of the slit 16 is the slit 1.
It is good if a light shielding portion is provided inside the through hole of slit 1 which is larger than the through hole of slit 5. Moreover, the effect of the present invention can be obtained even if the shape of each through hole is not limited to a circle but other shapes such as a rectangle.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the first... Second. a third slit, and a first slit that subtracts the electrical signal of the light that has passed through the through hole of the second slit from the electrical signal of the light that has passed through the through hole of the first slit.
and a second subtraction means for subtracting the output signal of the first subtraction means from the electrical signal of the light that has passed through the through hole of the third slit. The first slit has a size that allows normal decomposition, the first slit's through hole is larger than the third slit's through hole, and a light shielding part is formed inside the second slit. A noise point having a narrow area on the document is detected, and the noise signal component is suppressed as much as possible by the second subtraction means, and an image signal can be obtained in which the details of the image information are on the same level as the normal resolution, Therefore, without losing the details of the image on the original,
It is possible to re-record an image that is faithful to the original image by reducing isolated noise.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional image processing device, FIG. 2 is a waveform diagram of essential parts of the same device, FIG. 3 is a block diagram showing an embodiment of the image processing device of the present invention, and FIG. 4 is a block diagram showing an embodiment of the image processing device of the present invention. FIG. 6 is an example main part waveform diagram. 11... Manuscript, 12... Lens, 13
．． 14...Half mirror-115, 16, 17.
...Slit, 18,19.20...Photoelectric converter, 21,22゜23...Low pass filter, 24.25 Mountain...Operation amplifier. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 432 - Figure 2

Claims (1)

[Claims] An image is formed at an arbitrary position on the document, and each of the first . Second. and a third slit, a photoelectric conversion means for converting the light that has passed through each of the through holes into an electrical signal, and converting the electrical signal of the light that has passed through the through hole of the first slit into an electrical signal that is transmitted through the second slit. a first subtraction means for subtracting the electrical signal of the light that has passed through the hole; and subtracting the electrical signal obtained by the first subtraction means from the electrical signal of the light that has passed through the through-hole of the third slit. a second subtraction means for obtaining an image signal; Second. and each through hole of the third slit has the same center on the original document, the through hole of the third slit has a size that normally separates the image on the original document, and the through hole of the third slit has a size that normally separates the image on the original document, The through hole is larger than the through hole of the third slit, and the through hole of the second slit has a light shielding part inside.