KR20060010219A - Method for determining existence of image on document in image scanning device - Google Patents

Abstract

The present invention can improve the usability of the image scanning apparatus by determining the existence of images on both sides of the original (the original surface and / or the original surface) by using weighted shading data when shading correction implemented in the image scanning apparatus. A method for determining whether images exist on both sides of an original in an image scanning device.

To this end, the present invention provides a method for determining whether an image exists on both sides of an original using shading correction in an image scanning device, the method comprising: (a) applying a weight to shading correction data for shading correction to apply an image of an original; Shading correcting and storing the data; (b) gamma correcting and storing the shading corrected image data; (c) determining whether the gamma corrected image data is a white image, and if the gamma corrected image data is a white image, determining that there is no image on a corresponding document surface; (d) removing the gamma-corrected image data from the shading-corrected image data, and determining whether the image data from which the gamma-corrected image data has been removed is a white image. Determining that there is no image; characterized in that it comprises a.

Description

Method for determining existence of image on document in image scanning device}

1 is a block diagram of a general image scanning apparatus.

2 is a flowchart of a shading correction method according to the prior art.

3 is a flowchart of a method for determining whether images exist on both sides of an original in the image scanning apparatus according to the present invention.

<Description of the symbols for the main parts of the drawings>

1 ... scan control 2 ... ROM

3 ... RAM 110 ... Shading Memory

120 ... Shading Correction Control 130 ... Shading Correction Control

The present invention relates to a method for determining whether an image exists on both sides of an original in an image scanning apparatus. More particularly, the present invention relates to an original duplex (original surface) using shading data to which weights are applied during shading correction implemented in the image scanning apparatus. And / or the back side of the document), the present invention relates to a method for determining the presence or absence of images on both sides of an original in the image scanning apparatus, which can improve the usability of the image scanning apparatus.

As is well known to those skilled in the art, an image scanning device such as a scanner is the most common means for scanning color, black and white prints, photographs, or memos in the form of human hands. It is an essential component of a translator, facsimile, character recognizer and digital copier.

In recent years, as the demand for office automation equipment such as digital copiers, printers, scanners, and facsimile has increased so as to ride on the evolving office automation, each office automation equipment has a high performance to expand its own functions. In addition, each of the office automation equipment that was used independently is developed in one piece to reduce the economic burden and installation space for the user and at the same time produce and provide a product that performs a complex document output function. Such a device is called 'Multi-Function Peripheral' (MFP), and today, a multifunction device is a typical example of a device employing an image scanning device such as a scanner.

In other words, the multifunction device not only functions as a printer for printing data input from a host computer, but also as a scanner for reading image originals, a copy function for printing and copying scanned and scanned image originals, and an image original through a communication line. It is a device having a compound document output function that performs a function as a facsimile to be transmitted to a remote site. That is, it is a multi-function terminal made by weaving existing terminal devices such as facsimile machines, scanners, printers, and copiers into a single unit, and generally includes a host computer-interface function that is interoperable with a host computer.

As an example through the all-in-one, a number of products have been released that expand the function through the combination and interworking with the related office automation devices with the scanner as a basic component, the "image" referred to herein Scanning device "will be assumed to be a generic term for such image scanning device based devices, which is generally acceptable to one of ordinary skill in the art, due to the nature of the application of the present invention. would.

The present invention is directly related to a technique for performing shading correction in such an image scanning apparatus, and the shading correction of the image scanning apparatus will be described with reference to the accompanying drawings for the understanding of the present invention. .

In normal image processing, the shading phenomenon is a phenomenon occurring in an image pickup tube such as a videoconductor or a CRT, and refers to a phenomenon in which the brightness varies depending on the screen portion of a television. This is caused by non-uniformity of the target or secondary redistribution from the target to the target, which improves the distorted image quality by providing the adjusting electron lens. On the other hand, recently, the concept limited to the display device has been applied to an image input device such as an image scanning device as an extended concept having the same meaning. Shading correction is performed for image processing that removes such a shading phenomenon and improves distorted picture quality. This is called shading correction processing.                         

In other words, shading correction corrects that the left and right edges of the screen are darkened or deformed due to the characteristics of the optical system when digitizing general documents, aerial photographs, etc., to generate digital image data for computers. There is a method of correcting the density so that the entire screen has the same brightness by determining the conversion function of the concentration for each divided area, and shading correction is obtained by obtaining the shading data during the dummy scan. And how to do it.

1 is a block diagram illustrating an embodiment of a shading correction apparatus of a general image scanning apparatus.

Referring to FIG. 1, the image sensor unit 20 configured as image sensors for each of the three primary colors firstly reflects the reflected light input through the optical module unit 10 in proportion to the amount of light of each color component of B, G, and R. An analog image signal is obtained by forming an image on an image sensor of an image, and is driven at a predetermined timing according to a sensor driving clock provided from the scanning controller 1, and outputs a fixed number of pixels according to the resolution of each image sensor. Occurs. The scanning control unit 1 collects and radiates the light emitted from the lamp 12 controlled by the lamp driver 13 to the original and passes through a constant path in the amount of light reflected in proportion to the original density of the image sensor unit ( 20) to control the input. Accordingly, the input reflected light is converted into a voltage signal proportional to the intensity of the light and output according to the characteristics of the color image sensor which is a semiconductor device.

Thereafter, the analog / digital converter 100 converts the analog image signal of each color component output from the image sensor unit 20 into digital image data of each color component of a predetermined number of bits (m).

The shading memory 110 stores shading data obtained by analog-to-digital conversion of analog image signals of each color component obtained by scanning a shading reference pattern when performing pseudo scanning, at the address of each color component and each pixel position. The shading factor matrix stored in the shading correction controller 120 corresponds to each color component and each pixel position.

The shading memory 110 receives an output (i.e., shading data) from an image sensor of each color component formed by photoelectric conversion of the output of the spectrometer filter for each color component during pseudo scanning, and receives an address corresponding to each color component and each pixel position. Will be saved.

The shading correction control unit 120 reads each shading data stored in the shading memory 110 for each address during the pseudo scan, and calculates a predetermined maximum brightness value M in units of pixels, thereby calculating each color component and each pixel position. The shading factor matrix corresponding to the calculated shading factor matrix is calculated and provided to the shading memory 110, and the shading factor matrix stored in the shading memory 110 is stored when the real scanning is performed. Corresponding to the digital image data output from the analog / digital converter 100 for each color component and each pixel position, the output is performed.

Finally, the shading correction unit 130 may determine the digital image data of each color component output from the analog / digital conversion unit 100 and the shading factor matrix output under the control of the shading correction control unit 120 during the actual scan. The digital image data shading-corrected by multiplying each color component and each pixel position is output, thereby making it possible to obtain digital image data in which the output deviation between the color components is corrected.

In general, the image scanning apparatus may have a large deviation from system to system due to optical response characteristic differences and optical system assembly tolerances. It is desirable to be able to adjust these deviations mechanically in the assembled state, but in many cases it is technically difficult or impossible to solve this by image processing technique, which is the shading correction process as described above.

Here, the shading factor matrix is the most important factor for determining the characteristics of shading correction, and the white plate and white paper or white roller in which the image sensor unit 20 is installed on its opposite surface. Acquisition is through dummy scanning, which scans a shading correction pattern such as). It is apparent that the shading reference pattern used should have the same optical density as the white portion of the original.

The process of obtaining an original image through shading correction in the image scanning apparatus shown in FIG. 1 is briefly and clearly shown in FIG. 2.

Referring to FIG. 2, the method for acquiring an original image according to the related art includes: obtaining an original image in an image scanning apparatus, including reading and storing white data as a shading data storage step (S10); An original image storing step (S20) of reading and storing the original image; A shading correction step (S30) of correcting a pixel of the original image based on the pixel value of the stored shading data; A gamma correction step (S40) of correcting each pixel value based on a look up table; And storing the corrected image (S50).

That is, the conventional method for acquiring an original image uses a process of the above steps to read an original image and use it as a scanning image, and uses shading data correction and gamma correction to obtain a clearer scanning image.

However, according to the conventional image acquisition method according to the prior art, not only does not determine whether an image exists on the back side of the original, but also does not determine whether an image exists on the original side, and therefore, when scanning the original side or the back side of the original, If the image does not exist, there is a problem in that resources (eg, power, time, etc.) may be wasted.

Therefore, the technical problem to be achieved by the present invention is the ease of use of the image scanning apparatus by determining the existence of the image on both sides of the document (the original surface and the back surface) by using the shading data to which the weight is applied during shading correction implemented in the image scanning apparatus. The present invention provides a method for determining whether images exist on both sides of an original in an image scanning apparatus to improve the quality of the image.

The present invention provides a method for determining whether an image exists on both sides of an original using shading correction in an image scanning apparatus, in order to achieve the above technical problem, (a) weighting the shading correction data for shading correction; Shading-correcting and storing the image data of the original by applying; (b) gamma correcting and storing the shading corrected image data; (c) determining whether the gamma corrected image data is a white image, and if the gamma corrected image data is a white image, determining that there is no image on a corresponding document surface; (d) removing the gamma-corrected image data from the shading-corrected image data, and determining whether the image data from which the gamma-corrected image data has been removed is a white image. And determining that there is no image in the image providing apparatus.

In a preferred embodiment of the present invention, the weighted shading correction data is set within 10-30% of the saturation value, the saturation value being

It is obtained by "saturation value = weight value * (ADC data-black shading data) / (white shading data-black shading data)-weight value" ".

In a preferred embodiment of the present invention, in step (d), the removal of the gamma corrected image data retains pixels only when the gamma corrected image data is a white pixel, and all remaining pixels are white pixels. It can be changed and removed.

In a preferred embodiment of the present invention, a single thresholding image segmentation is used to remove background pixels due to weight shading when the threshold value is smaller than the threshold value, and the object behind the original larger than the threshold value. Dividing the pixels to obtain a threshold image,

When the total number of pixels of the threshold image is less than the reference value, it is determined as a white image.

Best Mode for Carrying Out the Invention Preferred embodiments of a method for determining whether images exist on both sides of an original in the image scanning apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that detailed descriptions of related well-known technologies or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

In the following description, when the member according to the prior art and the member according to the present invention are the same, the same reference numerals used in the prior art are used as they are, and detailed description thereof will be omitted.

3 is a flowchart of a method for determining whether images exist on both sides of an original in the image scanning apparatus according to the present invention.

It will be apparent to those skilled in the art that the flowchart algorithm of the present invention shown in FIG. 3 will be programmed and stored in the controller 1, 120, ROM 2, RAM 3 and the like shown in FIG. That is, the method of the present invention is preferably implemented by the hardware of the image scanning apparatus as shown in FIG.

Referring to FIG. 3, first, as in the prior art, white shading data is generated and read in order to know whether an image exists on each of both sides of an original, and the respective pixel values are stored in the memory 2 or 110 (FIG. 1). Store in (S110). Then, the controller 1 stores the image data in the memory while scanning the original (S120).

After scanning the original surface in step S120 and storing the image data in the memory, the control unit (1) 120 and the correction unit 130 apply the weight to the shading data stored in step S110 to scan the image data in step S120. Shading correction (S130).

In step S130, when the weighted shading correction, the weighted shading correction data is set within 10-30% of the saturation value, the saturation value is preferably the following formula, i.e.

According to "saturation value = weight value * (ADC data-black shading data) / (white shading data-black shading data)-weight value" ".

Shading-corrected image data by applying the weight in step S130 is stored in the memory of the image scanning apparatus under the control of the controller (1) 120 (S140), on the other hand is gamma-corrected and is also stored in the memory ( S150) (S160). The gamma correction is to correct each pixel based on the lookup table as in the prior art.

Image data that has been gamma corrected and stored in steps S150 and S160 is determined by the control of the controller 1 or 120 to determine whether the image data is a white image. That is, if the gamma corrected image data is a white image, the controller (1) 120 determines that there is no image on the original surface (S190).

Meanwhile, the controller (1) 120 removes and stores the gamma corrected image data from the shading correction image data stored in the memory through step S140 (S170) (S180). The image data stored in step S180 becomes image data on the back of the document. It is determined whether the image data on the back of the document stored in step S180 is a white image under the control of the controller (1) (120). That is, if the image data on the back of the document is a white image, the controller (1) 120 determines that there is no image on the back of the document (S190).

In step S170, the control unit 1, 120, and the correction unit 130 select a background pixel according to weight shading in the case where the weight is smaller than the threshold value by using a single thresholding image segmentation. The threshold image is obtained by removing the object pixels on the back of the original larger than the threshold value, and when the total number of pixels of the threshold image is less than the reference value, the image is determined as a white image.

Thus, the present invention determines whether an image exists on the original side or the back side of the original while maintaining the conventional scanning scheme, thereby transmitting the scanned image to a computer (PC), outputting to a printer, or transmitting via fax. In doing so, it is possible to improve the transmission speed of the image data and improve the use efficiency of the device.

As described above, in the image scanning apparatus according to the present invention, an image presence determination method of both sides of an original includes two sides of the original (the original surface and the back surface of the original) using shading data to which weights are applied during shading correction implemented in the image scanning apparatus. By determining the presence or absence of the image to provide an advantage to improve the ease of use of the image scanning device.

Although a preferred embodiment of the present invention has been described in detail above, those skilled in the art to which the present invention pertains may make various changes without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications or variations may be made. Therefore, changes in the future embodiments of the present invention will not be able to escape the technology of the present invention.

Claims (5)

A method for determining whether an image exists on both sides of an original by using shading correction in an image scanning device, shading-correcting and storing image data of an original by applying weights to shading correction data for shading correction; (b) gamma correcting and storing the shading corrected image data; (c) determining whether the gamma corrected image data is a white image, and if the gamma corrected image data is a white image, determining that there is no image on a corresponding document surface; (d) removing the gamma-corrected image data from the shading-corrected image data, and determining whether the image data from which the gamma-corrected image data has been removed is a white image. And determining that there is no image in the image scanning method. The method of claim 1, The weighted shading correction data is set within 10-30% of the saturation value, and the saturation value is Saturation Value = Weight Value * (ADC Data-Black Shading Data) / (White Shading Data-Black Shading Data)-Weight Value A method for judging whether an image exists on both sides of an original in an image scanning device, which is obtained by The method of claim 1, In the step (d), the gamma corrected image data may be removed by maintaining the pixel only when the gamma corrected image data is a white pixel, and changing the remaining pixels to white pixels. A method for determining whether images exist on both sides of an original in an image scanning device. The method of claim 1, Remove the background pixels due to the weighted shading when the threshold value is smaller than the threshold using a single thresholding image segmentation, and separate the object pixels behind the original larger than the threshold to obtain a threshold image. A method for determining whether an image exists on both sides of an original in an image scanning device, comprising: The method according to claim 1 or 4, And determining whether the image exists on both sides of the document in the image scanning apparatus, when the total number of pixels of the threshold image is less than a reference value.

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