TW486906B - Focus method of chart for image scanner - Google Patents

Abstract

Provided is a focus method of chart for image scanner. It first prepares a focus chart which includes a white base and several black straight graphics of different width. The direction of each black straight graphic is identical to the moving direction of the optics scanning module. The focus chart attaches to the scanning initial side of the manuscript carrying side of the image scanner. When proceeding focusing, it uses the optics scanning module to proceed focusing for the focus chart to obtain a focal distance value and calculate if the focal distance value is the best. Then it adjusts the focal distance of the optics scanning module according to the best focal distance value. When the optics scanning module proceeds formal scanning for a manuscript to be scanned, it uses the best focal distance value to proceed image scanning for the manuscript to be scanned.

Description

486906 V. Description of the invention (1) I. Field of the invention: The present invention relates to a focusing method of an image scanning device, in particular to a focusing test performed on an in-focus test sheet using an optical scanning module of the image scanning device to obtain A method for optimal focal length. The focus test sheet includes a white substrate and a plurality of black bars having different widths arranged on the white substrate. 2. Description of background: Scanners have been widely used in scanning, capturing and storing graphic images. Due to the advancement of scanning technology and the user's demand for scanning quality, the scanning resolution of the scanner is getting higher and higher, which also makes the focus of the scanning operation an important issue. A typical image scanner is shown in Figure 1. A rectangular window of appropriate size is opened in the central area of the top plate 11 of the scanner body 1, and a manuscript bearing surface 12 made of transparent glass is embedded for placing. Put a manuscript 2 to be scanned. An upper cover 13 is pivotally provided on the top side of the body 1 as a mask plate. When the image scanning device performs a reflective scanning operation, the upper cover 1 3 is a cover for a manuscript carrying a manuscript 2 to be scanned. Face 1 2 on. An optical scanning module 14 and guide rods 15 a and 15 b are set inside the scanning machine. The optical scanning module 14 is driven by a control circuit of the scanner and a conventional driving mechanism (not shown). Below, the displacement can be performed along the guide bars 15 a, 15 b (that is, the direction indicated by arrow I) to scan the manuscript 2 placed on the manuscript bearing surface 12. A light source 16, a plurality of reflective lenses 171, 172, 173, 174, a focusing lens 18, are disposed in the optical scanning module 14 (see FIG. 2).

486906 V. Description of the invention (2) and an image sensing element 19 (such as a charge-coupled element C C D) and other components. Most of the scanner products currently used generally perform the calibration procedure before the official scanning of the manuscript. After a predetermined correction procedure has been performed, the image scanning is performed on the document 2 to be scanned placed on the document bearing surface 12. A typical calibration procedure includes a focusing procedure. In order to perform the focusing procedure, a calibration area is generally set in advance on the scanning start side 10 of the document bearing surface 12 and the bottom surface of the top plate 11 of the scanner housing is adjacent to the scanning start side 10 Attach a focus test piece 3 (FocusCart). Therefore, the scanner can perform the focusing procedure on the focus test piece 3 before the document is scanned formally to ensure that a clear image with correct focus can be obtained when the document is formally scanned. As shown in FIG. 3, the conventional focus test piece 3 is basically composed of a plurality of white areas 31 and black areas 32 of a fixed width. In the focus test, asymptotic focusing is generally used to obtain an optimal focal length value, for example, the technology disclosed in the patent case of the Republic of China Patent Publication No. 3 9 5 1 13. In the future, the demand for scanner resolution is getting higher and higher, which will cause the problem of smaller depth of field. To get better image sharpness, you need to have better focus function. However, in the actual application of the scanner, the scanning resolution may vary depending on the needs of the user. For example, when scanning general images, the user may use a scanning resolution of 3 0 dpi to perform Scanning, and when scanning delicate pictures, users may choose to scan at a resolution of 1 200 dpi. In the case of different resolutions ’if the fixed black and white focus test piece is still aligned

486906 V. Description of the invention (3) In the focus test, the speed and focus accuracy of the focus test cannot be taken into account. Summary of the invention: Therefore, in view of the lack of the focusing method used by the conventional scanner, the main purpose of the present invention is to provide a focusing method of an image scanning device, so that when scanning a manuscript to be scanned formally, a The focus test piece performs the focus test. In addition to focusing, the focus test piece can also be used as the identification of the product serial number.

Another object of the present invention is to provide a focusing method for a test piece of an image scanning device, which provides a focusing test piece, the surface of which includes a white substrate and a plurality of black straight bar patterns of different widths. The direction is the same as the moving direction of the optical scanning module, and the focus test piece is attached to the scanning start side of the manuscript bearing surface of the image scanning device. Another object of the present invention is to provide a focusing method for different resolution test strips of an image scanning device, which provides a focus test strip, the surface of which includes a white substrate and a plurality of black bar patterns of different widths. During the focus test, a black straight bar pattern of a predetermined width can be selected as the pattern of the focus test according to the scanning resolution set by the user. Then, the optical scanning module performs a focus test on the black bar graph pattern of the selected focus test piece according to different resolution requirements.

In order to achieve the above-mentioned object of the present invention, in a preferred embodiment of the present invention, it first prepares a focus test piece. The focus test piece includes a white substrate and a plurality of black bar patterns of different widths. Working on

Page 6 486906 V. Description of the invention (4) During the focus test, the optical test module is used to perform a focus test on the focus test piece to obtain a focal length value, and calculate whether the focal length value is the optimal focal length value, and then based on The optimal focal length value adjusts the focal length of the optical scanning module. When the optical scanning module scans the document to be scanned formally, the document to be scanned is scanned with the optimal focus value. Preferably, the optical scanning module of the scanner can perform a focus test based on a wide black bar pattern or a narrow black bar pattern of the focus test piece according to different resolution requirements. When the resolution set by the user is low, the optical scanning module performs a focus test on a wide black histogram pattern, and when the resolution set by the user is high, the optical scanning module targets a narrow Black bar graph for focus test. The other objects of the present invention and its structural design will be further explained by the following embodiments and attached drawings, among which: (1) Brief description of the drawings. Fig. 1 is a perspective view showing a conventional image scanning device; The second series shows the optical path diagram of the conventional image scanning device in FIG. 1. The third series shows the schematic diagram of the conventional focus test sheet. The fourth series shows the schematic diagram of the focus test sheet used in the present invention. The fifth series shows the optical path diagram of the image scanning device of the present invention; the sixth series shows the control flowchart of the embodiment of the present invention. FIG. 7 shows a control flowchart of the second embodiment of the present invention. (2) Drawing number description: 1 Scanner body

486906 V. Description of the invention (5) 10 11 1 2 13 14 1 5a, 15b 16 171 ^ 172 > 173 > 174 18 19 2 3 31 32 4 41 42 43a 43b 5 6 , Which shows the scanning start side top plate manuscript bearing surface cover optical scanning module guide rod light source reflection lens focusing lens image sensing element to be scanned manuscript focus test piece white area black area focus test piece white base straight bar type Control unit of a bar chart type narrow bar type focus adjustment mechanism showing a focus test piece used in the present invention

Page 8 486906 V. Description of the plan of the invention (6) 4 The focus test piece 4 includes an area with a white substrate 41, and a plurality of vertical black bars are arranged on the white substrate 41 Type 4 2. In a preferred embodiment of the present invention, the black bar pattern 4 2 includes a plurality of wide bar patterns 4 3 a having a wide width, and a plurality of narrow bar patterns 4 3 b having a relatively small width. Figure 4 is a schematic diagram of the optical path and control architecture of the present invention. If there are components in the figure that are the same as those in Figure 2 above, they are marked with the same reference numbers for corresponding purposes. Figure 4 shows a manuscript 2 to be scanned placed on the manuscript bearing surface 1 2 of an image scanning device. Below the manuscript bearing surface 12, that is, the internal space of the scanner, an optical scanning module 14 is arranged. The optical scanning module 14 includes a light source 16 and a plurality of reflective lenses 1 7 1 and 1 7 2 , 1 7 3, 1 7 4, a focusing lens 18, and an image sensing element 19 (such as a charge-coupled element CCD). The focus test piece 4 used in the present invention is attached to the scanning start side 10 of the document bearing surface 12 of the image scanning device, and is located on the bottom surface of the top plate 11 of the image scanning device. The surface faces the optical scanning. Module 1 4. The extending directions of the histogram patterns 4 2 of the focus test piece 4 are the same as the moving direction I of the optical scanning module. The optical scanning module 14 is driven by a control unit 6 and a conventional driving mechanism (not shown), and can be displaced in the first direction I on the bottom surface of the manuscript bearing surface 12 to place the manuscript on the manuscript bearing surface 1. The manuscript 2 on 2 is scanned. The optical scanning module 3 can be driven by a focal length adjustment mechanism 5 to cause the optical scanning module 3 to be displaced in the second direction II (ie, the vertical direction) to adjust the optical scanning module 3 to correspond to Focal distance between focus test piece 4

486906 V. Description of the invention (7) In addition to the above-mentioned driving of the optical scanning module of the scanner by the focus adjustment mechanism 5 to move up and down to adjust the focus of the optical scanning module on the focus test piece, you can also change the focus lens 18 or the position of the image sensing element 19 can achieve the same focus adjustment function.

Fig. 5 is a control flowchart of the first embodiment of the present invention. The focusing method of the present invention uses the optical scanning module of the image scanning device to perform a formal manuscript scan before performing a focus test sheet as shown in Fig. 3. Perform a focus test. The focusing method of the present invention first reads the image data of the focus test piece 4 by using an optical scanning module (step 101), and calculates the focus obtained in the previous step under the calculation of the control unit 6 of the scanner. The image data of the test piece is calculated by a conventional method to calculate a focal length value (step 102). Then the control unit judges whether the focusing is completed by a conventional method (such as an approximate recognition method) (step 103). Focusing is completed, that is, the focal length value is set to the optimal focal length value. If not, under the control of the control unit 6, the focal length adjustment mechanism 5 adjusts the focal length of the optical scanning module 14 relative to the focus test piece (step 104) until the optimal focal length value is obtained. After performing the above-mentioned focus adjustment procedure, the optical scanning module of the scanner can formally scan the document to be scanned, and scan the document to be scanned with the optimal focus value.

FIG. 6 shows a control flowchart of the second embodiment of the present invention. The steps are mainly the same as the first embodiment shown in FIG. 5. The difference is that the user can set the required scanning resolution in step 200. In user settings

Page 10 486906 V. Description of the invention (8) After the required scanning resolution is selected, the control unit 6 will select a black bar pattern of a predetermined width in the focus test piece corresponding to the required scanning resolution to perform Subsequent focus test. In this way, the optical scanning module can choose a general focus test or a more precise focus test according to different resolution requirements set by the user. For example, when the user only needs to scan at a low resolution, the optical scanning module only needs to perform a focus test on a wide black bar pattern. This focus test mode takes less time; on the contrary When the user needs to perform high-resolution scanning, the optical scanning module will select a narrow black bar pattern for the focus test. This focus test mode takes more time. After step 2 0, the optical scanning module reads the image data of the black bar graph with a specific width in the focus test piece 4 (step 2 1), and calculates the result of the calculation by the control unit 6 of the scanner. The image data of the black bar graph with a specific width obtained in one step is calculated by a conventional method to calculate a focal length value (step 202). Then, the control unit judges whether the focusing is completed (step 203) by a conventional method (for example, the approximation recognition method). If it is determined that the focusing is completed, the focal length value is set as the optimal focal length value. If not, under the control of the control unit 6, the focal length adjustment mechanism 5 adjusts the focal length of the optical scanning module 14 with respect to the focus test piece (step 204) until the optimal focal length value is obtained. In summary, the focusing method of the image scanning device provided by the present invention can indeed achieve the expected effect, so the present invention has a high industrial use value. However, the above detailed description is only a description of a preferred embodiment of the present invention.

486906 V. Description of the invention (9) is not intended to limit the inventor. Therefore, all other improvements made by those skilled in the art based on the above description still belong to the spirit of the invention and the scope of patents defined below. .

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Claims (1)

486906 VI. Application Patent Scope 1 · A focusing method for test piece of image scanning device, which uses the optical scanning module of the image scanning device to perform a focus test on a focus test piece before performing manuscript scanning. The focusing method includes the following Steps: a. Preparing a focus test piece, the focus test piece includes a white substrate and a plurality of black bar patterns of different widths arranged on the white substrate; b. Reading the focus test with the optical scanning module Image data of the film; c. Calculating the focal length of the obtained focus test piece; d. Adjusting the focal length of the optical scanning module relative to the focus test piece to obtain an optimal focal length value; e. In the optical scanning mode When the group performs a formal scan, the document to be scanned is scanned with the optimal focus value. 2 · For the method of focusing on the test piece of the image scanning device according to item 1 of the patent application, wherein the directions of the black bar patterns of the focus test piece are the same as the moving direction of the optical scanning module. 3. For example, the method for focusing on a test piece of an image scanning device in the scope of patent application, wherein the focusing test piece is attached to the scanning start side of the document bearing surface of the image scanning device and faces the optical scanning module. . 4. An image scanning device focusing method using an optical scanning module of the image scanning device to perform a focus test on a focusing test piece before performing a document scan. The focusing method includes the following steps: a. Preparing a A focus test strip, the focus test strip includes a white substrate and a plurality of black bar patterns of different widths arranged on the white substrate; 486906 VI. Application for patent scope b. Set the required scanning resolution; c. Select the black bar graph of the focus test piece corresponding to the scanning resolution; d. Use the optical scanning module to read the selected focus The image data of the black bar graph of the test piece; e. Calculate the focal length value of the obtained focus test piece; f. Adjust the focal length of the optical scanning module relative to the focus test piece to obtain an optimal focus value; g. When the optical scanning module performs a formal scan, image scanning is performed on the document to be scanned with the optimal focal length value. 5. For example, the method of focusing on the test piece of the image scanning device in the scope of patent application No. 4, wherein the direction of each black bar graph pattern of the focus test piece is the same as the moving direction of the optical scanning module. 6. For example, the method for focusing on a test piece of an image scanning device according to item 4 of the patent application scope, wherein the focusing test piece is attached to the scanning start side of the document bearing surface of the image scanning device and faces the optical scanning module. . Page 14