TW571575B - Method for selecting a shading correcting line - Google Patents

Abstract

A method for selecting a shading correcting line is provided. Scanning a white reference source to obtain several scan lines. Averaging brightness values of pixels from identical columns in the scan lines to obtain a new scan line composed of pixels having median brightness values. Adding one count in shading counting number when an absolute value of a difference of the median brightness values between each pair of adjacent pixels in the new scan line not less than a specification value of shading definition. Selecting the new scan line as a shading correcting line when total shading counting number less than a specification number of shading counts.

Description

571575 V. Description of the invention (1) 5-1 Field of invention: The present invention is related to a kind of shading correction method, which is used for non-uniformity of captured images in an IV low image reading device. Sex. 5-2 Background of the Invention: An image reading device (R), green (G) ) And blue (B) an inverter, such as a charge-coupled device (CCD), to convert the analog signal of this ^ to an analog digital ^ f color flat converter

The line on the transparent scanning platform composed of the traditional color image reading board is on this original handle 'and receives the image on the original surface. One color light is captured and resolved into three primary colors, that is, red. The three primary colors are guided to an analog signal of a charge-coupled device. The three primary colors are converted into digital signals for output. In the above-mentioned image reading device, due to the actinicity from the light source, the conversion characteristics of the photoelectric conversion device that defines the pixel change with the change in f, and the change in light intensity caused by the light source supply voltage. Factors such as changes in intensity cause color distortion distortion.

571575 5. Description of the invention (2) When images with the same background brightness pass through the image reading device and the image is captured by the photoelectric conversion device, the intensity of the photoelectric conversion signal is not the same. Various methods of correction of color attenuation distortion have been developed. The fluctuation of the electronic signal output by the device can be minimized. Method so that the image reading device can output a signal when capturing an image with the same consistent shade. These color distortion correction methods are called shading correction. The color correction method is to use a photoelectric conversion device to extract correction data from a white calibration plate through a photoelectric conversion device and to block the photoelectric conversion device and Scanning the black attenuation correction data, generalizing the captured original image and θ, placing a white correction plate at a special position, and placing the white correction plate on the optical path of the scanning source. Before the original is scanned, this image is captured and captured by the photoelectric conversion device for prediction. Based on these color decay correction data, the green material can be corrected. ° Because the white calibration plate is not an optical scan, the electrons output by the device so that the photoelectric conversion is performed by these electron correction methods that correct the brightness of the scene are consistent. The reference white decay Reference line color attenuation correction. The optical system color correction plate for a manuscript outside the scanning platform is scanned to obtain color attenuation correction data. The original image data is in the fresh state. 571575 5. Description of the invention (3) That is, the photoelectric conversion device may capture The electronic noise reduces the reliability of the reference white attenuation correction data and the reference black attenuation correction data. Therefore, it is not possible to perform optimized color attenuation correction every time. In this way, proper color attenuation correction cannot be performed on the captured image. Accordingly, there is an urgent need to provide a color decay correction method, which can use a color decay correction curve having a good color decay correction value for color decay correction, thereby improving the credibility of the ancient output image. 5-3 The purpose and summary of the invention: The main object of the present invention is to provide a method for selecting a color decay correction curve. The color decay correction curve selected by the method of the present invention has better color decay. #Shading correction value, A better color attenuation corrected image can be obtained. Another object of the present invention is to provide a method for selecting a color decay correction curve, which can make a read image with high confidence. Another object of the present invention is to provide a method for selecting a color decay correction curve, which can remove the adverse effects caused by impulse noise and dust accumulation on a white color correction plate.

Page 7 571575 V. Description of the invention (4) Another object of the present invention is to provide an image color decay method, which can calculate the true shading counting number of an acquired image, so as to determine whether to adopt This image. According to the number of levels of the curve, the prime brightness value is the same as the brightness method described above. The present invention is directed to the first scan line. From these first average brightness values, it is known that when the drawing line includes each value of these bright pairs of adjacent pixels, the color attenuation number is smaller than the correction curve color attenuation correction attenuation number (shading one color attenuation number specification. By the present invention, In order to obtain a better method, the present invention provides a method including knowing and drawing a reference white, in which the first scanning line is a scanning line, each vertical direction is taken to obtain an absolute value of the pixel luminance difference composed of a horizontal average. When the value is not small, select the second scanning method to correct the image with better color decay. Area to obtain a plurality of scanning lines including pixels in a plurality of image directions. Article. When the second scan is in a color decay specification σ ~. When the total color is used as the one-color decay correction value for the purpose of carrying out the 1st Japanese Maoyue and its many advantages, the following specific implementations will be implemented: Will become clearer. Detailed description of 5 ~ 4 specific embodiments: The figure is used to illustrate one image reading device of the method of the present invention

No. 571575 5. Schematic diagram of the structure of the feeder unit 10 of the invention description (5). The paper feeder unit 10 includes a white reference plate 1 00, a light source 1 01, a light source driver (not shown), a lens group 1 02-04, and a lens 1 05. An optical system, a shading plate 106, a shading plate driver (not shown), a linear light sensing device 107, and a transparent scanning platform (not shown). A scanned original 108 is placed on this transparent scanning platform. White 4 and positive plate 100 are used to obtain reference white attenuation correction data for shading correction. As shown in the first figure, the white calibration plate 100 can be placed on one side of the transparent scanning platform. The light source 101 may be a fluorescent lamp or a toothed lamp, which projects the light onto the white calibration plate 100 and scans the original document i Q 8 i. The light source driver (not shown) is used to drive the light source i〇 丄 to move in the direction of arrow A so that it can project light onto the entire original surface of the scanned original i 08, as shown in the first figure. The optical system including the lens group 102-104 and the lens 105 is to guide the light reflected from the scanned original 108 to the linear light sensor 007 to form a light-receiving plane on the light-receiving plane. image. A shading plate 1 〇 6 is used to block the light receiving plane of the linear light sensor 1 07 to obtain reference black attenuation correction data.

571575 V. Description of the invention (6) The linear light sensor i 0 7 for color attenuation correction can be a linear charge transfer device (CCD Hne SenSor) or-contact image sensor (contact wage sensor) . An analog / digital converter (not shown) is used to convert the analog signal sent by the linear light sensor i 07 into an 8-bit digital signal. These read 8-bit digital signals are subjected to color attenuation correction using a color attenuation correction curve established according to the method of the present invention. f Another method of obtaining reference black attenuation correction data in the invention is to turn off 01 and perform image data light operation by the linear light sensor 107 to capture the reflected light from the white correction plate 100. Since the light of the white '& 0 1 is not projected on the white correction plate 100, there is no reflection light projected from the front plate 1 00. In this way, the linear light α ^ is 10 7 to capture reference black attenuation correction data. The method of selecting the color decay correction curve by the invented invention is described in detail below with specific embodiments and " drawings '. Illustration. ΐ The diagram and the second B diagram are the steps of the specific embodiment of the present invention. + w —The diagram is based on the technical idea of the present invention, and the & First, in step 200, scan a reference white area i ==== white calibration plate to obtain a plurality of horizontal scanning lines, such as scanning lines Li, L2, and L3 shown in one round. Each horizontal scanning line L1,

Page 10 571575 V. Description of the invention (7) L2 and Ls respectively include a plurality of pixel brightness values (p

P Ρΐ, Ρ, ιΡ.

Pi, η ρ 1,35 1 1, 4 ^ 2,4 ', 5 ..., P2, η) and are not limited to only capturing three horizontal sweeps 3: η: and' 本^ The horizontal scan and line of the method. Then, any number can be acquired in the step to obtain a new horizontal scanning line: prime two: the average value of V bright Λ, Lh T ^. G This new horizontal scanning line Lavg includes these Pixels hh- · Pc… ·… * ρ, which are composed of average brightness.丄 # 二 I’avg, K2’avg, as shown in the second figure, the brightness is flat

1, 5 (P 3, 1

P 3, 2 3, 3 (ρ2, ιρ, 3, 4 ρ2, 2, 3, 5 3'avg, i4, avg, _i5, avg,, mean P2, avg is the pixel brightness value Pi 2 ρ 2, 3 The average value of PO. Next, take the new phase m2 〇2 'take this new horizontal scanning line, each-= phase = prime absolute value of the difference, such as 丨 Δρ23 丨, ιδρ " i? 招 t 耆, in step 2 〇3, when the absolute value of each difference is not less than -color =, ..., the color attenuation number (shading c〇unt ing) is added to :, at step 204, determine this new scan line Is the total color f number of Lavg not less than the one-color attenuation number specification value. At step 2 05, when the total color is not within this color number specification value, the new horizontal scan, Lavg, is discarded. At step 2 〇6, when the total color attenuation number is smaller than the color attenuation number specification P, the new horizontal scanning line L avg is used as a color attenuation correction curve, and the color attenuation correction curve has a better color attenuation correction value (shadinge〇Re (Cti〇n value). In addition, after the color attenuation correction curve is established, the shirt image material is manipulated, and the color attenuation correction is performed on the captured image data according to the established color attenuation correction curve.

571575 V. Description of Invention (8) Yu? = $ Ϊ m #The establishment of the line u step A of the second A picture: refer to the black area to obtain a plurality of horizontal directions. The present invention can be borrowed by using a shadlng plate Y pixel to the linear light sensor i 〇7 to provide this reference black area. On the other hand, by turning off the light source 10i and using a linear light sensor 丄 07 to perform image data capture operations, the reference data is obtained. Then, proceed to step 2.丄, 2, 2,;, "Fathers 0 4, 2 0 5 and 2 6 to establish a reference black attenuation correction curve. 2 Cold mouth In another aspect of the present invention, according to the second A and second B examples It can also calculate a captured bright image or dark image / counting number) j Know whether the image can be used, that is, by using the method of the present invention, you can also obtain the f image. The following test For example, in step 2000, a specific area is changed into a bright part image, and the bright part image is scanned to obtain a white horizontal scanning line, such as the scanning lines Li, l2, and [. The f horizontal scanning lines L1, L2, and 1 ^ 3 each contain a plurality of bright ▲ 1-Tang ΓΓ ρ β D ρ η η _, 1 1 豕 '^ 焭 Ρ, 1, 1 3,? 2 , 4, P〗 ′ Ρ3, η). However, the method of the present invention is not limited to capturing only three ^ lines, and can also capture any number of horizontal scanning lines. Then, ^ scanning 2 0 1, From these horizontal scanning lines, take the average value of the brightness of each vertical direction = one of the sudden brightness values to obtain a new horizontal scanning line element 1, 2, 1, 4, 1, 2, ... P2, ) And (P3, l5 Ρ3,2

Pi, (ρ, ρ 3, 3 2, 1: 3, 4, ρ 2, 2

Page 12 571575 V. Description of the invention (9)

Lavg, where the new i, avg, Γ2, and corpse pp are lost as shown in the second picture, aVg, r4, avg ^^ 5, avg, ..., which is not shown in the picture. # 丰-命 杜 乃 p 丨 J 徂 广 2, _ your pixel value is one of the average of 1 to 3,2. Ππ a 卜. 卜 —— pixels consisting of values (P / τ handle line contains these brightness averages n, avg

Hua Zhuo, one of Pl, 2, P2 2 and P3 2 .. ▲ —, n, vu / again m-New level: Scan: Come from U 'At step 2 0 2, take this value, for example, ΛΛ the — When the absolute value of the difference between adjacent pixels is / 1,., And the value is not less than one color attenuation specification value, the color attenuation number a lng counting number) is increased by one. Next, determine whether the new scan line L is in the factory step 2. The bismuth method is not less than one or more than C. Step 2 0 5, when the total color decay number is not Less than this color decay number Γ; Γ “Γί The image of this -bright portion extracted in step 2 0 0. Using Υ · ^ 2 6, * When the red number is less than the color decay number specification value, it is used in step 2 The image of this bright part captured by 0 0. The method of judging the color decay number of Caimu Niu's image is based on the two silly figures in the second A picture. Change the party image to a dark image, scan this- Dark part & image to obtain a number of horizontal scanning lines, each of which includes a plurality of dark part pixel values, and continue to perform step 2: 〇2, 2 0 3, 2 0 4, 2 0 5 and 2 0 6. At = 2 0 5, when the total color number is not less than the color attenuation number specification value, that is, the dark image captured in step 2 00. In step 2 0 6, the color number is less than When the color attenuation number is specified, the dark image obtained in step 2 00 ^^ is used. Juice 571575 5. Description of the invention (ίο) According to the above, the method of the present invention can provide A color decay correction curve with a better color decay correction value to obtain a better color decay corrected image. By using the method of the present invention, the read image can also have high reliability, and at the same time, instantaneous noise can be removed ( impulse noise) and the adverse effects of dust accumulation on the white calibration plate.

The above are only specific embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the following Within the scope of patent application.

571575 on page 14 is a simple illustration. The first diagram is a schematic structural diagram of a paper feeder unit of an image reading device; the second diagram A and the second diagram B are flowcharts of a specific embodiment of the present invention; and the third diagram is The step of selecting a color decay correction curve according to the technical idea of the present invention is an illustrative diagram.

Symbols of the main parts: 10 Feeder unit 10 0 White calibration plate 10 1 Light source 1 0 2-1 0 4 Lens group 10 5 Lens 10 6 Mask 10 7 Linear light sensor

10 8 Scanning Originals

Page 15

Claims (1)

571575 6. The scope of the patent application includes: 1. A method for selecting the color attenuation correction curve of the bright part image, which includes ^ ^ examining the white area to obtain a plurality of horizontal first scanning lines. The first: scanning line system includes a plurality of Pixel brightness values; in the first scan line, the pixel brightness values in each longitudinal direction are taken as an average value of a shell degree to obtain a horizontal second scan line, the second scan line < Contains pixels composed of these average brightness values; when the absolute value of the brightness difference between each pair of adjacent pixels of the second scanning line of Tian 4 is less than one color decay specification value, the color decay number is increased by one; and the margin is used as the wide color / number When it is smaller than the one-color attenuation number specification value, the second scan and the depth are selected as the one-color attenuation correction curve. Method 2, · The white area of the Lingling test that is included in one of the color decay correction curves described in item 1 of Zhongshen / Shandong Loss-of-Specific Loss Guide contains a white calibration plate. Method 3: The multiple first scanning lines described by the device for selecting a color decay correction curve described in the first item of the patent application range are described by a linear charge closing method. This item was taken by a tester that selects the color decay correction curve described in the item. The α plurality of first scanning lines are a method of selecting a color attenuation correction curve of a dark image by a contact image sensing method. Page 16 571575 6. The scope of patent application includes: Scanning a reference black area to obtain a plurality of lines. A scanning line contains a plurality of references: plugging in to the brother, the first = = both: every vertical direction! The second scanning line including the reference black pixel includes the second scanning line. When each of the second scanning line is -2: the element; the absolute value is not less than one color, and the black pixel is considered. When the total color decay number is less than the color / number ζ number plus one; and the number specification value, the 哕 筮 -㈡t line is selected as the one-color decay correction curve. The younger brother knows the description of Fang Sheng 6, 'Pot as described in Λ, the selection of the color decay correction curve described in item 5 of the patent range', and the McCoy black area described above includes a black correction plate. 7. The 'selection of the color attenuation correction curve' as described in item 5 of the scope of the patent application, wherein the first scanning line is obtained by drawing a white calibration plate with a light source turned off. 8.Select the color decay correction curve ^ 所述 as described in item 5 of Shenjing's patent scope, where the first scanning line described above is in the case of using a shield to block a light receiving plane of a light-sensing 'beam 1' state. , Obtained by scanning a white calibration plate. 9. 571575 for selecting a color attenuation correction curve as described in item 8 of the scope of patent application 6. Method of patent scope, wherein the above-mentioned light sensor is a linear charge coupled device. 10. The method for selecting a color attenuation correction curve as described in item 8 of the scope of the patent application, wherein the above-mentioned light sensor is a contact image sensor. 11. An image color decay judgment method, comprising: scanning a specific image to obtain a plurality of horizontal first scanning lines, the first scanning line including a plurality of pixel values; From the first scan lines, one pixel average value of the pixel values in each longitudinal direction is taken to obtain a horizontal scan line. The second scan line includes pixels composed of the average values of the pixels. ; When the absolute value of the pixel difference of each pair of adjacent pixels of the second scanning line is not less than the one-color attenuation specification value, the color attenuation number is increased by one; and when the total color attenuation number is less than the one-color attenuation specification value, it is adopted That particular image. 12. The method for determining the color decay of an image as described in item 11 of the scope of patent application, wherein the specific image mentioned above includes a highlight image. 1 3. The method for determining color decay of an image according to item 11 of the scope of patent application, wherein the specific image mentioned above includes a dark image. 14. The method for judging the color decay of an image as described in item 11 of the scope of the patent application, wherein the plurality of first scanning lines are formed by a linear charge coupled device Page 18 571575 VI. Patent application scope 15 · The method for determining color decay of an image as described in item 11 of the scope of patent application, wherein the plurality of first scanning lines are captured by a contact image sensor. Page 19