JP2010103874A - Image processing apparatus, program and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus, program and storage medium in which, even without causing a user to determine whether to perform dust/flaw correction, if there is dust/flaw, the dust/flaw is corrected and if there is not dust/flaw, a processing time is shortened. <P>SOLUTION: An image processing apparatus for scanning a transmission original placed on an original platen and correcting dust/flaw on the transmission original includes: a dust/flaw detecting means for a visible image for reading a visible image, analyzing the read visible image and detecting dust/flaw; a dust/flaw detecting means for an infrared image for reading an infrared image, analyzing the read infrared image and detecting dust/flaw; a dust/flaw correcting means for correcting the dust/flaw detected by the dust/flaw detecting means for the infrared image; and a determination means for determining whether to output a read visible image or to read an infrared image and output a visible image dust/flaw corrected using the dust/flaw detecting means for the infrared image, in accordance with a result of analyzing the read visible image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that reads a transparent original placed on a platen of an image reading apparatus, processes the read image, and outputs the processed image. In particular, the present invention detects dust and scratches attached to a transparent original. The present invention relates to an image processing apparatus that determines and corrects dust and scratches using an infrared image.

  In recent years, with the development of communication networks, the speeding up of computers, and the increase in capacity of storage media, image information is frequently handled. In particular, there is an increasing demand for more accurate and high-speed reading of image information captured by a scanner or the like.

  Conventionally, there is an image processing method for acquiring an infrared image, detecting dust / scratches based on the infrared image, and correcting a visible image in order to remove dust / scratches attached to a transparent original.

  When detecting dust / scratches, dust / scratches are detected by utilizing the difference between the infrared light transmittance of the pigment of the transparent document and the infrared light transmittance of dust / scratches. In this way, it is possible to read a high-quality image with few detection misjudgments and less noticeable dust and scratches. However, since it is necessary to read an infrared image, there is a problem that the processing time is longer than a reading method in which dust and scratches are not corrected without reading the infrared image.

  Therefore, the user selects whether to correct dust / scratches and take a long time, but to read with high quality, or to read at high speed without dust / scratch correction.

Further, in order to shorten the time required for dust / scratch detection, there is a proposal for acquiring an infrared image with a preview resolution and, if necessary, acquiring an infrared image with a desired resolution (for example, Patent Documents). 1). Also, a proposal for acquiring an infrared image with low resolution and correcting dust / scratches is known (for example, see Patent Document 2).
JP 2001-245118 A JP 2006-157809 A

  With the conventional proposal, the time required for dust / scratch detection can be shortened, but since infrared light is read and judged, it is difficult to make the processing time comparable to the processing time when only a visible image is read. There is a problem. For this reason, there is a problem that a setting item for setting whether or not to correct is necessary.

  On the other hand, there is also a demand to easily read an image without making complicated settings. In response to this request, selecting whether or not dust / scratch correction is performed has a problem that it is contrary to the request to read an image easily without complicated settings.

  Even if the user does not determine whether to correct dust / scratches, the present invention corrects the dust / scratches if there is dust / scratches. If there is no dust / scratches, the image processing apparatus has a short processing time. An object is to provide a program and a storage medium.

  The present invention reads a transparent document placed on a document table, reads a visible image in an image processing apparatus that corrects dust and scratches on the transparent document, analyzes the read visible image, and detects dust and scratches. The visible image dust / scratch detection means, the infrared image dust / scratch detection means for detecting the dust / scratch by reading the infrared image and analyzing the read infrared image, and the infrared image dust Depending on the result of analyzing the dust / scratch correcting means for detecting dust / scratches detected by the scratch detection means and the read visible image, the read visible image is output or the infrared image is read, and the red An image processing apparatus comprising: a determination unit that determines whether to output a visible image corrected for dust / scratches by using the dust / scratch detection unit for external images.

  According to the present invention, even if the user does not determine whether to correct dust / scratches, if there is dust / scratches, the dust / scratch is corrected, and if there is no dust / scratches, the processing time is short. Play.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a cross-sectional view illustrating an image reading apparatus R1 that is Embodiment 1 of the present invention.

  The image reading apparatus R1 includes a scanner 101, a transparent original unit 102, and a read original 103.

  The scanner 101 is connected to a host computer (hereinafter referred to as “host PC”) by an interface cable (not shown). Further, the scanner 101 includes a moving optical unit 104, an original table glass 105, an electric board 106, a pulse motor 107, an endless belt 108, pulleys 109 and 110, a gear train 111, a guide rail 112, and a white color. And a reference plate 113.

  A black mark 136 is provided in the white reference plate 113, and the scanner 101 determines a reading area based on the black mark 136 and reads an image. The movable optical unit 104 and the pulse motor 107 are electrically connected by a cable (not shown). The movable optical unit 104 is placed on the placement unit 114 and can slide along the guide rail 112. The placement unit 114 is fixed to the endless belt 108.

  The moving optical unit 104 includes a reflective document light source 115, a plurality of reflecting mirrors 116, 117, and 118, an imaging lens 119, and a line sensor 120 that is an imaging unit.

  With this configuration, it is possible to read a reflected original image. However, reading the reflected original image is not related to the embodiment, and thus the description thereof is omitted.

  Next, in the first embodiment, a transparent original image reading operation in the scanner 101 will be described.

  The scanner 101 turns off the reflection original light source 115 of the moving optical unit 104, turns on the transmission original light source 135, and moves the movement optical unit 104 to a position for reading the transmission original. The original transmitted light from the transmission original light source 135 is reflected through a plurality of reflecting mirrors 116, 117, and 118, and formed on the line sensor 120 through the imaging lens 119, thereby the main scanning direction 1. Read the line image.

  Further, the pulley 109 is rotated by the power of the pulse motor 107 via the gear train 111 to drive the endless belt 108. Accordingly, the moving optical unit 104 fixed to the endless belt 108 moves on the guide rail in the sub-scanning direction indicated by the arrow X via the placement unit 114.

  The scanner 101 repeats reading the line image in the main scanning direction while moving the moving optical unit 104 in the sub-scanning direction. The scanner 101 moves the moving optical unit 104 from the left end in FIG. 1 to a position indicated by a dotted line while performing a reading operation, and thereby scans the entire surface of the document table glass 105.

  Note that a partial image of a document on the platen glass 105 may be read according to the content of a read command from the host. In this case, with respect to the read image area designated by the host, the pixel area adopted in the sensor output is realized in the main scanning direction, and the movement area of the optical unit is set in the sub scanning direction. This is realized by defining the above control unit. When the optical unit is moved in the sub-scanning direction, the system controller 226 selects a speed and reads an image according to the resolution setting for image reading specified by the host.

  FIG. 2 is a block diagram illustrating a functional configuration of the scanner 101 according to the first embodiment.

  The scanner 101 is an example of an image processing apparatus that reads a transparent document placed on a document table and corrects dust and scratches on the transparent document.

  In addition, the same number is attached | subjected to the same structure as the structure shown in FIG. 1, and the description is abbreviate | omitted.

  The scanner 101 includes a moving optical unit 104, an electric substrate 106, a pulse motor 107, a transmissive original light source 135, and a motor drive circuit 225.

  The moving optical unit 104 includes a light source lighting circuit 224. The light source lighting circuit 224 is a circuit that lights the light source 115 for the reflective original and the light source 135 for the transparent original. Includes a detector to do. When cold cathode fluorescent lamps are used for the reflective original light source 115 and the transparent original light source 135, a so-called inverter circuit is configured.

  The electric board 106 includes a system controller 226, analog gain adjusters 227R, 227G, and 227B, an A / D converter 228, an image processing unit 229, a line buffer 230, and an interface unit 231. The electric board 106 also includes an offset RAM 232, a gamma RAM 233, and a system bus 234.

  The analog gain adjusters 227R, 227G, and 227B variably amplify the analog image signal output from the line sensor 120.

  The A / D converter 228 converts the analog image signal output from the analog gain adjusters 227R, 227G, and 227B into a digital image signal. The image processing unit 229 performs image processing such as offset correction, shading correction, digital gain adjustment, color balance adjustment, masking, resolution conversion in the main and sub scanning directions, and image compression on the digital image signal.

  The line buffer 230 temporarily stores image data and has a general-purpose random access memory. The interface unit 231 communicates with the host PC 221. Here, the USB interface is used, but another interface such as IEEE1394 may be used.

  The offset RAM 232 is a RAM used as a working area when performing image processing, and the RGB line sensors have a predetermined offset with respect to each other and are arranged in parallel to the line sensor 120. Therefore, it is used for correcting the offset between the RGB lines. The offset RAM 232 also temporarily stores various data such as shading correction. Here, it is realized by a general-purpose random access memory. The gamma RAM 233 is a RAM for storing a gamma curve and performing gamma correction.

  The system controller 226 is a system controller that stores a sequence of the entire film scanner, and performs various controls in accordance with instructions from the host PC 221.

  The system bus 234 connects the system controller 226, the image processing unit 229, the line buffer 230, the interface unit 231, the offset RAM 232, and the gamma RAM 233, and includes an address bus and a data bus.

  The motor drive circuit 225 is a motor drive circuit for the pulse motor 107 and outputs an excitation switching signal for the pulse motor 107 in response to a signal from a system controller 226 that is a system control unit of the scanner 101.

  The image processing unit 229 is an example of a visible image dust / scratch detection unit that reads a visible image, analyzes the read visible image, and detects dust / scratches, and reads an infrared image. This is an example of infrared image dust / scratch detection means for analyzing an image and detecting dust / scratches. The image processing unit 229 is an example of a dust / scratch correcting unit that corrects dust / scratches detected by the infrared image dust / scratch detecting unit. Further, the image processing unit 229 determines whether to output the read visible image or the infrared image corrected by the dust / scratch correcting unit according to the analysis result of the read visible image. It is an example of a means.

  In this case, the determination unit is a unit that determines to output the read visible image if the area of dust / scratch detected by analyzing the visible image is less than a threshold value. The determination means is a means for reading an infrared image and outputting a visible image corrected for dust / scratches using infrared image dust / scratch detection means if it is equal to or greater than a threshold value.

  Next, a schematic configuration of a general host PC 221 used for controlling the scanner 101 in the first embodiment will be described.

  FIG. 3 is a diagram illustrating a schematic configuration of a general host PC 221 used for controlling the scanner 101 in the first embodiment.

  The host PC 221 includes a ROM 307, a RAM 308, a central processing unit 309, a disk device 310, a bus 311, an I / F 312, an I / F 313, and an external storage device 314.

  FIG. 4 is a flowchart illustrating an operation of determining a document reading document area of the scanner 101 by the host PC 221 in the first embodiment.

  The ROM 307 holds a program that realizes the operation of the flowchart shown in FIG. The RAM 308 provides a storage area and a work area necessary for the operation of the program. The central processing unit 309 performs processing according to a program held in the ROM 307.

  The bus 311 connects the above-described components, and enables data exchange between the components. The I / F 312 is an I / F that communicates with the scanner 101 and is realized by a USB interface, like the interface unit 231 of the scanner 101. However, another interface such as IEEE1394 may be adopted. Good. The I / F 313 is connected to an input unit 320 such as a mouse or a keyboard.

  The external storage device 314 drives an external storage medium such as a floppy (registered trademark) disk or a CD-ROM. As described above, the external storage device 314 is stored in the external storage medium instead of holding the control program in the ROM 307 in advance. If so, read it and download it. Note that the control program may be downloaded via a network via a network connector (not shown).

  Next, the reading operation of the scanner 101 by the host PC 221 in the first embodiment will be described.

  In step S401, a preview image is read from the scanner. This preview image is not an image to be provided to the user, but is for setting the position and size of the image to be provided, exposure setting at the time of reading, and reading time setting. For this reason, it reads at a resolution lower than the resolution desired by the user.

  In step S402, the position / size of the image provided to the user is determined from the preview image. For example, the edge of the frame shown on the transparent original is extracted, and the position / size of the image that provides the user with a rectangle surrounding the extracted edge is determined.

  In step S403, exposure setting and reading time setting are performed from the preview image. For example, in the case of a negative film, which is a typical transparent original, the density is very high. Therefore, when read with the same setting as that for reading a preview image, noise in a dark part is conspicuous. In order to prevent this, the exposure time and reading time are set so that the reading can be performed at an appropriate density. For example, when the inside of the position / size of the image provided to the user obtained in S402 is read, a sufficiently long exposure time / reading time is set without the image being saturated.

  In S404, the visible image provided to the user is read. This reading range is a range corresponding to the position / size of the frame obtained in S402, and the reading setting is the exposure time / reading time setting obtained in S403.

  FIG. 5 is a diagram illustrating an example of a read visible image.

  FIG. 5 shows a visible image 501 read when there is no dust / scratch and a visible image 502 read when there is dust / scratch.

  In S405, the visible image read in S404 is analyzed. By this analysis, dust and scratches are extracted. For example, if a photographic document includes a dust / scratch area, the photographic document has a different statistical property from that of the photographic document. Therefore, the dispersion of a specific area is obtained, and the dust / scratch area is obtained by threshold processing. Details of this will be described later.

  In addition, since the position where the differential component sharply changes in the image is likely to be the edge of dust / scratches, the dust / scratch region can be obtained.

  FIG. 6 is a diagram illustrating an example of an analyzed image.

  In the analysis result 601 in the case where there is no dust / scratch, the edge of the image is erroneously determined and detected. However, since there is no dust / scratch, the area of the detected dust / scratch region is small. In the analysis result 602 in the case where there is dust / scratch, dust / scratch is detected, so the area of the detected dust / scratch area is large.

  In S406, it is determined whether the area of the dust / scratch extracted in S405 exceeds a threshold value. If large debris is attached to the film, the extracted debris / scratch area is large, so the threshold is exceeded.

  In S407, the range necessary for correcting dust / scratches is read with infrared light.

  In step S408, dust / scratches are detected based on the infrared image, and dust / scratches are removed from the visible image at the detected position.

  When detecting dust / scratches in an infrared image, use the difference between the infrared transmittance of the dust / scratches attached to the film and the infrared transmittance of the film to remove dust attached to the film.・ Detects scratches and objects on film with high accuracy. Thereafter, using the pixels around the detected dust / scratch position, information lost due to the dust / scratch is interpolated to perform dust / scratch correction processing. In S409, the visible image is transferred and provided to the user.

  In other words, if it is determined that the area of dust / scratches as a result of analysis in S406 is equal to or greater than the threshold value, the visible image after the dust / scratch removal processing is transferred in S408, in S409. If it is determined in S406 that the analysis result is less than the threshold value, the visible image read in S404 is transferred in S409.

  Although not shown in the flowchart of FIG. 4, when a plurality of frames are captured on the film, if the position / size of a plurality of dust / scratches is detected in S 402, the process returns to S 403. Subsequent processing may be performed.

  Next, in the visible image analysis (S405), a process for obtaining a standard deviation of a specific area, performing threshold processing, and obtaining a dust / scratch area will be described.

  FIG. 7 is a flowchart illustrating processing for obtaining a dust / scratch region from a visible image in the first embodiment.

  In step S701, the visible image is grayscaled. As a gray scale method, the following formula may be used, or another method may be used.

Y = 0.30 × R-ch + 0.59 × G-ch + 0.11 × B-ch
In step S702, the grayscale image is divided into blocks. Since the detection target pixel size due to dust and scratches changes depending on the resolution, the block size is changed according to the resolution. Moreover, since there is a possibility that image continuity is lost when blocks are divided, continuity is maintained by dividing the blocks so that they overlap.

  In S703, the average value and standard deviation of each block are obtained. The average value is obtained by averaging the gray scale values. When the standard deviation is obtained, the difference between the addition average and the gray scale value is square-averaged. If the standard deviation is small, the image is uniform, and if the standard deviation is large, it is a complicated part. The standard deviation is obtained for all the divided blocks.

  In step S704, a threshold for detecting dust / scratches is set for the calculated standard deviation. When setting the threshold, the multiplication of the standard deviation in the block and the coefficient is set. However, the coefficient is changed according to the standard deviation of each block. For example, if the standard deviation is small, the image is uniform, and it is thought that there are few dusts and scratches. Therefore, the coefficient value is increased so as not to cause erroneous detection. On the contrary, if the standard deviation is large, the image is complicated and there is a possibility that dust and scratches are included. Therefore, the coefficient is made small to facilitate detection.

  For example, if the standard deviation is 2.0 or less, it is considered that there is little dust and scratches, so the coefficient is set to 1.5. If the standard deviation is greater than 2.0 and less than or equal to 4.0, the coefficient is set to 1.0. If the standard deviation is larger than 4.0, the coefficient is set to 2.0.

  In step S705, a dust / scratch area is obtained according to the average value, standard deviation, and coefficient obtained in each block. In the case of a negative film, a pixel having a value larger than (average + standard deviation × coefficient) is defined as a dust / scratch region. In the case of a positive film, a pixel having a value smaller than (average + standard deviation × coefficient) is defined as a dust / scratch region.

  As described above, according to the embodiment described above, a visible image necessary for output is analyzed, infrared light is read, and it is determined whether dust / scratch correction is performed. As a result of this determination, the time required for dust / scratch correction can be eliminated in the case of a transparent original having no dust / scratches attached thereto. On the other hand, in the case of a transparent original with dust and scratches attached, infrared light is read and dust and scratches are corrected, so that a high-quality image can be provided.

  The second embodiment of the present invention is an embodiment applicable to a system constituted by a plurality of devices (for example, a host computer, an interface device, a scanner, a printer, a multifunction device, etc.).

  Further, a storage medium (or recording medium) in which a program code of software that realizes the functions of the above embodiments is recorded is supplied to the system or apparatus. Then, the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

  In other words, the second embodiment has a multi-crop function that reads a plurality of documents at once when a plurality of documents are placed on the document table of the image reading apparatus and scans, and automatically reads the read documents. A program for controlling the image processing apparatus. The second embodiment has a detected crop image number detection procedure for detecting the number of detected crop images, which is the number of sheets detected by cutting out the document placed on the document table. In the second embodiment, a crop image number comparison procedure for comparing the number of desired crop images input by the user with the number of detected crop images, and a comparison result display procedure for displaying a result of comparison in the crop image number comparison procedure. Is a program that causes a computer to execute.

  In this case, the program code itself read from the storage medium realizes the functions of the above embodiments, and the storage medium storing the program code constitutes the present invention. Further, the functions of the above-described embodiments are realized by executing the program code read by the computer. In addition to this, an operating system (OS) or the like running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above embodiments are realized by this processing. This is also included.

  Here, the storage medium for storing the program code is, for example, a flexible disk, hard disk, ROM, RAM, magnetic tape, non-volatile memory card, CD-ROM, CD-R, DVD, optical disk, magneto-optical disk, MO, etc. It is.

  Further, the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, a CPU or the like provided in the function expansion card or function expansion unit executes part or all of the actual processing, and according to this processing, The function is realized.

  In other words, the program code is a program that causes a computer to function as each means constituting the image processing apparatus according to claim 1. The storage medium storing the program code is a computer-readable storage medium storing the program according to claim 3.

  According to the above embodiment, a visible image necessary for output is analyzed, and it is determined whether or not dust / scratch correction is performed by reading infrared light.・ The time required for flaw correction can be eliminated. Further, according to the above-described embodiment, in the case of a transmission original with dust / scratches attached, infrared light is read and dust / scratches are corrected, so that a high-quality image can be provided. Furthermore, according to the above-described embodiment, whether or not to correct dust / scratches is automatically determined based on the read visible image without determining by the user, so that the determination / operation of the user is reduced.

It is sectional drawing which shows image reading apparatus R1 which is Example 1 of this invention. 3 is a block diagram illustrating a functional configuration of a scanner 101 in Embodiment 1. FIG. 2 is a diagram illustrating a schematic configuration of a general host PC 221 used for controlling a scanner 101 in Embodiment 1. FIG. 6 is a flowchart illustrating an operation of determining an original reading original area of the scanner 101 by the host PC 221 in the first embodiment. It is a figure which shows the example of the read visible image. It is a figure which shows the example of the analyzed image. 6 is a flowchart illustrating processing for obtaining a dust / scratch region from a visible image in the first embodiment.

Explanation of symbols

R1... Image reading device,
101 ... Scanner,
106: electric board,
229 ... an image processing unit,
221: Host PC,
309: Central processing unit.

Claims (4)

In an image processing apparatus that reads a transparent document placed on a document table and corrects dust and scratches on the transparent document,
A visible image dust / scratch detection means for reading a visible image, analyzing the read visible image, and detecting dust / scratches;
An infrared image dust / scratch detection means for reading an infrared image and analyzing the read infrared image to detect dust / scratches;
Dust / scratch correcting means for correcting dust / scratches detected by the infrared image dust / scratch detecting means;
Depending on the result of analyzing the read visible image, the read visible image is output or the infrared image is read, and the visible image corrected for dust / scratches using the infrared image dust / scratch detection means is used. Determining means for determining whether to output;
An image processing apparatus comprising: In claim 1,
The determining means analyzes the visible image, determines that the area of dust / scratch detected is less than a threshold value, determines to output the read visible image, and if greater than the threshold value, reads the infrared image, An image processing apparatus, characterized in that it is means for outputting a visible image corrected for dust / scratches using the infrared image dust / scratch detection means.   A program for causing a computer to function as each means constituting the image processing apparatus according to claim 1.   A computer-readable storage medium storing the program according to claim 3.

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