KR20060061441A - Multi-function product capable of setting adaptive contrast and method thereof - Google Patents

Abstract

Disclosed are a multifunction apparatus and method for setting an adaptive contrast capable of adaptively setting contrast according to an analysis result by analyzing a histogram of an original. In this copying method using the multifunction apparatus for setting the adaptive contrast, a histogram is generated using scanning data read from a predetermined area of an original to be copied, and a specific brightness value corresponding to the text area of the original is detected from the generated histogram. And comparing the specific brightness value with the preset reference value, setting a contrast to be applied to the original, and copying the original by applying the set contrast. This makes it possible to set a suitable contrast using the histogram of the original to improve the quality of the copy. In particular, in the case of continuous copying of a plurality of originals, even if each of the originals has a difference in density, the same contrast can be applied to prevent deterioration of the copy quality caused by copying the original.

Contrast, Adaptive, Histogram, Multifunction

Description

Multi-function product capable of setting adaptive contrast and its method

1 is a block diagram of a conventional copier,

2 is a flowchart illustrating a copying method using a conventional multifunction printer;

3 is a block diagram of a multifunction apparatus for setting adaptive contrast according to an embodiment of the present invention;

4 is a flowchart illustrating a copying method using a multifunction apparatus for setting an adaptive contrast according to an embodiment of the present invention;

5 is a view showing an area set for analyzing a histogram of an original copied in a multifunction apparatus according to an embodiment of the present invention; and

6A to 6D are diagrams for explaining a process of analyzing a histogram of an original copied in a multifunction apparatus for setting an adaptive contrast according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

210: image sensor 220: correction unit

230: signal processing unit 240: storage unit

241: First storage unit 243: Second storage unit

250: control unit 260: histogram unit

261: generation unit 263: analysis unit

270: printing unit 280: printing memory

290: interface unit

The present invention relates to a multifunction apparatus for setting an adaptive contrast and a method thereof, and more particularly, a multifunction apparatus for setting an adaptive contrast that can be copied by adaptively applying contrast according to an analysis result by analyzing a histogram of an original; It's about how.

1 is a block diagram of a conventional copier.

Referring to FIG. 1, a conventional copier includes an image sensor 110, a correction unit 120, a signal processing unit 130, a control unit 140, a printing unit 150, and a printing memory 160.

First, the image sensor 110 photoelectrically converts light reflected from an original to be copied to generate an image signal. In general, an image sensor 110 uses a contact image sensor (CIS) or a charge coupled device (CCD).

Correction unit 120 is a phenomenon that the distortion of the image signal occurs due to the light source variation or light amount unevenness when the light applied to the original from the light source is reflected from the original photoelectric conversion by the image sensor 110 to generate an image signal Perform shading correction to correct. The correction unit 120 performs gamma correction to correct a brightness level of a relatively dark image signal under bright lighting.

The signal processor 130 converts the analog signal corrected after being output from the image sensor 110 into a digital signal. In addition, the signal processor 130 processes the signal by applying the set contrast.

The print memory 160 stores print data signal processed by the signal processor 130, and the print unit 150 prints the print data stored in the print memory 160.

The controller 140 controls the overall operation of the components of the multifunction device.

2 is a flowchart illustrating a copying method using a conventional copying machine.

Referring to FIG. 2, the documents are loaded into the automatic feeder of the copier so that a plurality of documents can be continuously copied (S51).

Next, the contrast to be applied when copying the originals is selected, and a copy command is input (S53). The contrast to be applied when copying the originals can be selected from the contrast types such as 'Auto', 'Dark', 'Normal' and 'Bright' displayed. After the contrast is selected, an operation panel unit (not shown) is used to instruct copying of the originals loaded in the automatic document feeder.

When the contrast to be applied is set and a copy command is input, the document to be copied is scanned (S55). When a copy command is input, the image sensor 110 photoelectrically converts the light reflected from the document to generate an image signal, and the generated image signal is subjected to shading correction or gamma correction.

The corrected image signal is binarized in accordance with the selected contrast (S57). The selected contrast is applied to the corrected picture signal and converted into binary data that can be printed by the printing unit 150.

The binarized image signal is transmitted to the print memory 160 (S59).

Print data stored in the print memory 160 is printed by the printing unit 150 (S61).

However, the continuous copying method using a copying machine having a conventional automatic paper feeder has a problem in that the originals are copied because the set contrast is equally applied when the density of the originals loaded in the automatic paper feeder is different. . In addition, even when copying the document intermittently rather than continuous copying, it is necessary to improve the copy quality by applying contrast to reflect the density of the original.

Accordingly, an object of the present invention is to provide a multifunction apparatus and method for setting an adaptive contrast that can improve the quality of a copy by analyzing a histogram of an original to be copied and applying a contrast according to the analysis result. .

In order to achieve the above object, a copying method using a complex setting adaptive contrast according to the present invention comprises the steps of (a) generating a histogram using scanning data read from a predetermined area of an original to be copied, (b) Detecting a specific brightness value corresponding to the text area of the original in the histogram, (c) comparing the specific brightness value with a preset reference value, setting a contrast to be applied to the original, and (d) setting the contrast. Copying the original by applying.

Preferably, step (b) comprises averaging the histogram by calculating an average between neighboring brightness values in the histogram to reduce the concentration deviation of the generated histogram, and deriving the derivative value between neighboring brightness values in the averaged histogram. Calculating a maximum derivative value in the text area and detecting a brightness value corresponding to the maximum derivative value.

Preferably, step (c) increases the contrast when the reference value is smaller than the specific brightness value and sets the contrast by decreasing the contrast when the reference value is larger than the specific brightness value.

Meanwhile, the multifunction apparatus for setting the adaptive contrast according to the present invention generates scanning data by photoelectrically converting light reflected from an original to be copied, and an image processing unit which performs signal processing so that the scanning data can be printed, and scanning a predetermined area of the original. A histogram is generated using the data, and a histogram unit for detecting a specific brightness value by analyzing the generated histogram, a setting unit for setting a contrast to be applied to the scanning data by comparing the specific brightness value with a preset reference value, and scanning data And a storage unit for storing a predetermined reference value, and a printing unit for printing signal processing scanning data by applying the set contrast.

Preferably, the histogram unit calculates the derivative value between neighboring brightness values in the averaged histogram and averages the histogram by calculating an average between neighboring brightness values in the histogram in order to reduce the concentration deviation of the generated histogram. The maximum derivative value in the area is detected, and the brightness value corresponding to the maximum derivative value is detected as a specific brightness value.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

In the following description, a case of continuously copying a plurality of originals in a multifunction device will be described.

3 is a block diagram of a multifunction apparatus for setting adaptive contrast according to an embodiment of the present invention.

Referring to FIG. 3, the multifunction apparatus for setting the adaptive contrast according to the present invention includes an image sensor 210, a correction unit 220, a signal processor 230, a storage unit 240, a controller 250, and a histogram unit 260. ), A printing unit 270, a printing memory 280, and an interface unit 290. The storage unit 240 includes a first storage unit 241 and a second storage unit 243, and the histogram unit 260 includes a generation unit 261 and an analysis unit 263.

First, when continuously copying a plurality of documents using an automatic document feeder (ADF), the image sensor 210 photoelectrically converts the light reflected from the documents supplied from the automatic feeder to generate scanning data. .

The correction unit 220 performs shading correction and gamma correction of the scanning data output from the image sensor 210. Here, in the shading correction, when the light applied to the original from the light source is reflected from the original and photoelectrically converted by the image sensor 110 to generate the scanning data, distortion of the scanning data is generated due to the variation of the light source or the uneven amount of light. To correct that. And gamma correction refers to the correction of the brightness level in order to correct the relative darkening in the space under bright lighting.

The signal processor 230 converts the scanning data corrected by the corrector 220 into data that can be printed by the printer 270. That is, the signal processor 230 binarizes the scanning data.

The storage unit 240 includes a first storage unit 241 and a second storage unit 243. The first storage unit 241 stores shading data and gamma data used for shading correction and gamma correction performed by the correction unit 220. In addition, it stores a program for the operation sequence for the image processing process, and stores a reference value that is a reference for determining the contrast to be applied to the original to be copied. The scanning area used for generating the histogram among the areas of the original to be copied is preset and stored. Therefore, a histogram is generated using scanning data of a preset scanning area.

The second storage unit 243 temporarily stores the scanning data generated by the image sensor 210. In particular, the scanning data of the scanning area located before the scanning area used for generating a preset histogram is stored. Since contrast cannot be applied to scanning data before the scanning area used to generate the histogram, the scanning data is stored in the second storage unit 243 until the contrast is determined.

The histogram unit 260 includes a generation unit 261 and an analysis unit 263, and provides data that can set the contrast to be applied to the original by analyzing the histogram of the original to be copied. The generation unit 261 generates a histogram of a predetermined area of the document supplied from the automatic document feeder. The analysis unit 263 analyzes the histogram of the original generated by the generation unit 261 and detects the brightness value of the area constituting the skeleton of the text in the original. The detected brightness value is used to determine the contrast to be applied to the original.

The controller 250 generally controls the components of the multifunction apparatus, and sets the contrast based on the results of the histogram analyzed by the analyzer 263. Specifically, by comparing the brightness value detected by the analysis unit 263 and the reference value stored in the first storage unit 241, the contrast to be applied to the original is determined.

The print memory 280 receives and stores the scanning data to which the contrast is applied from the controller 250.

The printing unit 270 prints the scanning data stored in the print memory 280.

The interface unit 290 provides an interface for transmitting and receiving data with other devices such as a computer and a printer.

4 is a flowchart illustrating a copying method using a multifunction apparatus for setting an adaptive contrast according to an embodiment of the present invention.

Referring to FIG. 4, in order to successively plural documents, the documents to be copied are loaded into the automatic document feeder of the multifunction apparatus (S401).

Subsequently, an automatic contrast setting is input, and a copy command for the loaded original is input (S403). Select the Contrast setting menu among the menus for setting the copy environment, and select auto contrast from the contrast types that can be set. When the user selects to automatically apply the contrast applied to the originals, different contrasts are applied according to the density of each original. However, by selecting a specific contrast from the contrast setting menu, the same specific contrast can be applied to all the documents loaded in the automatic document feeder.

Subsequently, a predetermined region, which is a histogram analysis region, is scanned from the copied document (S405). The region for analyzing the histogram of the predetermined area among the areas of the original is set in advance, and the information on the position of the predetermined predetermined area is stored in the storage unit 240. In this case, it is preferable that the predetermined area is set as the start area of the original so that the histogram analysis of the original can be performed early, and it is desirable to set the area including the central area of the original which is likely to have text characters. This is because determining the contrast based on the density of the area where the text letters exist can improve the quality of the copy.

In addition, it is preferable to maintain the driving speed of the image sensor 210 at a low speed in order to obtain accurate scanning data in the areas determined as predetermined regions and to transmit the acquired scanning data to the second storage unit 243.

Subsequently, the scanning data is stored, and a histogram is generated using scanning data of a predetermined region which is a histogram analysis region (S407). When the predetermined area includes an area after the start area of the original, the scanning data read while the histogram is analyzed using the scanning data read in the predetermined area is stored in the second storage unit 243. The histogram is generated by the generation unit 261 using scanning data of a predetermined region.

Subsequently, contrast is set based on the generated histogram (S409). The contrast is set by comparing the brightness value corresponding to the maximum derivative value of the histogram area corresponding to the text area of the original with the reference value stored in the first storage unit 241 in the histogram generated by using the scanning data read in the predetermined area. .

For example, if the contrast setting menu is 'Dark', 'Normal' or 'Bright', as a result of comparing the brightness value corresponding to the maximum derivative value with the reference value, if the reference value is large, set the contrast to 'Bright' and In this small case, set the contrast to 'dark'.

Subsequently, the scanning data is binarized by applying the contrast set using the histogram (S411). When the contrast is set, the contrast is first applied to the scanning data stored in the second storage unit 243 and converted into data that can be printed by the printing unit 270. After the contrast is set, the contrast is applied to the scanning data read out to convert the data into printable data.

Subsequently, the binarized scanning data is transmitted to the print memory 280 (S413). Data stored in the print memory 280 is printed by the printing unit 270 (S415).

Then, it is determined whether there is another document loaded in the automatic document feeder (S417). As a result of the determination, if another original exists, the process after step S405 is repeated, and if another original does not exist, the procedure ends.

FIG. 5 is a diagram illustrating an area set for analyzing a histogram of an original copied in a multifunction apparatus according to an embodiment of the present invention.

Referring to Fig. 5, a predetermined area of one of the originals copied continuously is set as an area for analyzing the histogram. Information about the position of a predetermined area of the original document is stored in the first storage unit 241.

The criterion for setting the predetermined area is to include the center area of the original in which the text characters are likely to exist among the areas of the original. At this time, when reading the scanning data of the region for analyzing the histogram, the scanning speed is maintained at a low speed so that the scanning data of the predetermined region can be read accurately.

6A to 6D are diagrams for explaining a process of analyzing a histogram of an original copied in a multifunction apparatus for setting an adaptive contrast according to an embodiment of the present invention. FIG. 6A is a diagram showing a histogram generated by using scanning data read from a predetermined area of a document, and FIG. 6B is a view after averaging the generated histogram. 6C is a diagram illustrating the derivative of the averaged histogram. Here, each test①, test②, and test③ are arbitrary manuscripts. FIG. 6D is a diagram illustrating regions in which the letters are divided in the histograms of FIGS. 6A to 6C in a text-written document.

Referring to FIG. 6A, a histogram is generated by using scanning data read in a predetermined area set as an area for histogram analysis. Here, the horizontal axis of the graph is the brightness, and the vertical axis represents the frequency corresponding to each brightness. In addition, the area A is an area forming the text skeleton in the manuscript, and shows an increasing trend starting from the case where the frequency is 50 to 100, and refers to the area up to the first inflection point in FIG. 6B. The area C is mostly white in the background of the manuscript, and shows a steep increase in the histogram and a relatively high frequency. Area B has a similar distribution for each letter due to low resolving power when scanning an area having a medium brightness between area A and area C, and has a relatively uniform distribution concentration.

Referring to FIG. 6B, since the frequency deviation between neighboring brightnesses is large, the generated histogram is averaged. That is, the histogram is averaged by taking the average of frequencies between neighboring brightnesses. In this case, in order to reduce the amount of calculation to be averaged, the histogram having a brightness value between 50 and 200 is averaged.

Referring to Figure 6c, the derivative value is calculated from the averaged histogram. This is because using the averaged histogram, the difference in concentration cannot be accurately distinguished. The contrast is determined by comparing the maximum value in the region A, which forms the skeleton of the letter, in the histogram with the derivative value with a preset reference value. That is, the contrast is determined based on the brightness values (X, Y, Z) corresponding to the maximum differential value among the character areas of the histogram analysis area. Here, the X value is the brightness value corresponding to the maximum derivative value in the text area of the test① manuscript, the Y value is the brightness value corresponding to the maximum derivative value in the text area of the test② document, and the Z value is the maximum derivative value in the text area of the test③ document. Brightness value corresponding to. For example, when determining the contrast of the test document, compare the X value with a preset reference value.

Referring to FIG. 6D, areas A, B, and C of the histogram are displayed on an original with letters.

As described above, according to the present invention, an appropriate contrast can be set using the histogram of the original to improve the quality of the copy. In particular, in the case of continuous copying of a plurality of originals, even if each of the originals has a difference in density, the same contrast can be applied to prevent deterioration of the copy quality caused by copying the original.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (5)

(a) generating a histogram using scanning data read from a predetermined area of an original to be copied; (b) detecting a specific brightness value corresponding to a text area of the original from the generated histogram; (c) comparing the specific brightness value with a preset reference value and setting a contrast to be applied to the original; And (d) copying the document by applying the set contrast; and a copying method using a multifunction apparatus for setting an adaptive contrast. The method of claim 1, In step (b), Averaging the histogram by calculating an average between neighboring brightness values in the histogram to reduce the concentration deviation of the generated histogram; And Calculating a derivative value between neighboring brightness values in the averaged histogram to detect a maximum derivative value in the text area, and detecting a brightness value corresponding to the maximum derivative value; and adaptive contrast. Copy method using multifunction device to set the. The method of claim 1, Step (c) is, When the reference value is smaller than the specific brightness value, the contrast is increased, and when the reference value is larger than the specific brightness value, the contrast is set by setting the contrast. How to copy. An image processor which generates scanning data by photoelectrically converting light reflected from an original to be copied, and processing the signal so that the scanning data can be printed; A histogram unit for generating a histogram using scanning data of a predetermined area of the original, and detecting a specific brightness value by analyzing the generated histogram; A setting unit configured to set a contrast to be applied to the scanning data by comparing the specific brightness value with a preset reference value; A storage unit which stores the scanning data and the preset reference value; And And a printing unit which prints the scanning data signal-processed by applying the set contrast. The method of claim 4, wherein The histogram unit, In order to reduce the concentration deviation of the generated histogram, the average of the histograms is averaged by calculating an average between neighboring brightness values in the histogram, and then a derivative value between neighboring brightness values in the averaged histogram is calculated, and the text area of the original. And detecting the maximum derivative value from and detecting the brightness value corresponding to the maximum derivative value as the specific brightness value.

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