JP3563975B2 - Image reading apparatus, image reading method, and storage medium - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus for reading a document image such as a developed photographic film, an image reading method, and a storage medium storing the reading method as a program.
[0002]
[Prior art]
In a conventional film image reading device (hereinafter, referred to as a film scanner), an illumination optical system irradiates a transmission original such as a microfilm or a photographic film from behind, and the transmitted light is imaged by a photoelectric conversion element through a projection optical system. The image information of the film original is electrically converted by projecting and forming an image on a surface and performing photoelectric conversion by a photoelectric conversion element.
[0003]
However, in such a conventional apparatus, dust attached to the illumination optical system and the projection optical system, and scratches and dust on the film original appear as black spots on the read image data, resulting in image deterioration. was there.
[0004]
FIG. 14 schematically shows the influence of the above-mentioned dust and scratches on the image data and the output image. FIG. 14 (A) shows the case of a reversal film, and FIG. 14 (B) shows the case of a negative film. is there. As shown in FIG. 14, regardless of whether a reversal film or a negative film is used, when a film original is converted into an image signal by a film scanner and read, the above-described dust and scratches appear as black dots on the image signal.
[0005]
As a result, as shown in FIG. 14A, in the case of a reversal film, the above-described image signal is directly subjected to image processing such as gamma correction and output to an output device such as a printer. The effect appears as a black spot. On the other hand, in the case of a negative film, as shown in FIG. 14B, a negative image is converted to a positive image by subtracting an image signal read by a film scanner from an image signal read at a full level. Therefore, the influence of the above-described dust and scratches appears as a white bright spot on the output image.
[0006]
Focusing on the transmittance characteristics of the film to infrared light, only the dust and scratches that cause the image quality degradation described above are detected by infrared light transmitted through the original, and corrected to original data read based on the detected dust information. Has been proposed. FIG. 10 is a perspective view of a main part of a film scanner having such a correction function, FIG. 11 is a schematic configuration diagram of the film scanner shown in FIG. 10, and FIG. 12 is a block diagram showing a circuit configuration of the film scanner shown in FIG. FIG. 13 and FIG. 13 are flowcharts for controlling the operation of the film scanner shown in FIG.
[0007]
As shown in FIGS. 10 and 11, the present film scanner is a film carriage 1 that is used as a document table and fixes a developed film 2 (film original, transparent original), and emission characteristics from a visible light wavelength region to an infrared wavelength. And a line sensor 6 (reading means) composed of a lamp 3, a mirror 4, a lens 5, a CCD, etc., serving as a light source. Light emitted from the lamp 3 passes through the film 102, is reflected by the mirror 4, and is imaged on the line sensor 6 by the lens 5. The line sensor 6 has three light receiving regions of an R (red) light receiving portion, a G (green) light receiving portion, and a B (blue) light receiving portion, and has sensitivity to red, green, and blue light wavelengths, respectively. Having. At least one of the R (red) light receiving portion, the G (green) light receiving portion, and the B (blue) light receiving portion has sensitivity to infrared light.
[0008]
Further, a motor 7 (scanning means) for moving the film carriage 1 in a scanning direction (the direction of the arrow in FIGS. 10 and 11), a sensor 8 for detecting the position of the film carriage 1, an infrared light A filter 10a for cutting off the light, a filter 10b for cutting off visible light, and a filter motor 11 for moving the filter 10. By driving the filter motor 11, an infrared cut filter 10a is placed on the optical axis 9. And the visible light cut filter 10b can be switched and disposed. Furthermore, a control circuit 12, a lens holder 13 for holding the lens 5, an outer case 14 of a film scanner, an input / output terminal 15 for image information, a density sensor 16 for detecting film density, and a filter for detecting the position of the filter 10. Sensor 17 is provided.
[0009]
The lamp 3, the line sensor 6, the motor 7, the sensor 8, the filter motor 11, and the input / output terminal 15 are electrically connected to the control circuit 12 so as to be controlled. As shown in FIG. 12, the control circuit 12 (control means) includes a sensor control circuit 12a, a density sensor control circuit 12b, a filter sensor control circuit 12c, a motor control circuit 12d, a filter motor control circuit 12e, an image information processing. It comprises a circuit 12f, a lamp control circuit 12g, a line sensor control circuit 12h, a film density detection circuit 12i, a motor drive speed determination circuit 12j, and an image information storage circuit 12k.
[0010]
Next, a method of reading image information of the film 2 will be described with reference to the flowchart of FIG.
[0011]
(Step 101) When a film reading command is input from the outside through the input / output terminal 15, the position of the film carriage 1 is detected by the sensor 8 and the sensor control circuit 12a, and this information is transmitted to the film scanner control circuit 12. Then, the motor 7 is driven by the motor control circuit 12d to cause the film carriage 1 to wait at a predetermined standby position, and the film carriage 1 is moved to the standby position.
[0012]
(Step 102) The position of the filter 10 is detected by the filter sensor 17 and the filter sensor control circuit 12c, and this information is transmitted to the film scanner control circuit 12. Then, in order to dispose the infrared cut filter 10 a on the optical axis 9, the filter motor 11 is driven by the filter motor control circuit 12 e to move the infrared cut filter 10 a onto the optical axis 9.
[0013]
(Step 103) The density of the film 2 is detected by the density sensor 16 and the film density detection circuit 12i.
[0014]
(Step 104) The motor drive speed is determined based on this information.
[0015]
(Step 105) The position of the filter 10 is detected by the filter sensor 17 and the filter sensor control circuit 12c, and this information is transmitted to the film scanner control circuit 12. Then, in order to arrange the visible light cut filter 10b on the optical axis 9, the filter motor control circuit 12e drives the filter motor 11 to move the visible light cut filter 10b onto the optical axis 9.
[0016]
(Step 106) The lamp 3 is turned on by the lamp control circuit 12g.
[0017]
(Step 107) The motor 7 is rotated in a predetermined direction by the motor control circuit 12d at the previously determined driving speed, and a scanning operation for obtaining image information of the film 2 by infrared light is performed. During scanning, image information is transmitted from the line sensor 6 to the image information processing circuit 12f through the line sensor control circuit 12h.
[0018]
(Step 108) Using the obtained image information, an area on the film 2 whose infrared light transmittance is different from the most other area on the film 2 by a predetermined value or more is detected, and the area is detected as dust or dirt. Recognizes the presence of scratches and creates range information.
[0019]
(Step 109) The position of the filter 10 is detected by the filter sensor 17 and the filter sensor control circuit 12c, and the filter motor 11 is driven by the filter motor control circuit 12e to move the infrared cut filter 10a onto the optical axis 9. Move.
[0020]
(Step 110) The motor 7 is rotated in the opposite direction by the motor control circuit 12d at the drive speed determined in Step 4, and a scanning operation for obtaining image information of the film 2 by visible light is performed. During this scan, image information is transmitted from the line sensor 6 to the image information processing circuit 12f through the line sensor control circuit 12h.
[0021]
(Step 111) When the scanning operation is completed, the lamp 3 is turned off by the lamp control circuit 12g, the range information of dust and scratches is transmitted from the image information storage circuit 12k to the image information processing circuit 12f, and the image information of the film 2 by visible light is transmitted. Is output, and the film image reading operation of the film scanner ends.
[0022]
(Step 112) Based on the range information of dust and scratches created in step 8, the image information of the film 2 is corrected by visible light and output from the output terminal 15.
[0023]
In this way, a film scanner that detects and corrects dust and scratches described above is configured, but in order to correct by comparing data of dust and scratches detected by infrared light irradiation with visible light image data of the latter, Each image data must be registered with high precision. However, since scanning by infrared light for reading dust and flaws and scanning for reading visible light image data are performed separately, exact alignment is almost impossible due to backlash of the scanning mechanism. Therefore, in the above-described scanner, the dust and flaw data is appropriately expanded to make it seem larger, and the system is configured to correct the image data based on the expanded data.
[0024]
[Problems to be solved by the invention]
However, in such a film scanner, the data of the detected dust or scratch is extended and used, so that there is a possibility that image information originally having no dust or scratch is erased. Conversely, when the size to be expanded is smaller than the difference between the two pieces of image information to be compared, there is a possibility that dust and scratches cannot be sufficiently eliminated.
[0025]
SUMMARY OF THE INVENTION An object of the present invention is to obtain a well-corrected film image by accurately and easily specifying a dust / scratch region by reducing a shift generated when comparing a dust image information image and a visible light image in a film image. That is.
[0026]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and in the image reading apparatus according to claim 1, the image reading device reads the original from invisible light image data obtained by scanning the original while irradiating invisible light. Abnormality detecting means for detecting an abnormal region, a visible light image corresponding to the abnormal region in visible light image data obtained by scanning the original while irradiating the visible light, and an abnormality in the invisible light image data. A shift detecting unit that detects a shift from the invisible light image corresponding to the region, and a correcting unit that corrects a shift between the visible light image and the invisible light image detected by the shift detecting unit, I do.
[0027]
In the image reading method according to the fifth aspect, an abnormality detection step of detecting an abnormal region on the document from invisible light image data obtained by scanning the document while irradiating the invisible light, and irradiating the visible light with A shift detection step of detecting a shift between a visible light image corresponding to the abnormal region in the visible light image data obtained by scanning the document and the invisible light image corresponding to the abnormal region in the invisible light image data; A correction step of correcting a shift between the visible light image and the invisible light image detected by the shift detection step.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
《First form》
The image reading apparatus used in the present embodiment is assumed to be the film scanner described with reference to FIGS. 10 to 12, and the configuration is the same as that described above, and a description thereof will be omitted. Of course, the above configuration is merely an example, and the present invention is not limited to this configuration.
[0029]
FIG. 1 is a flowchart for explaining the operation of the film scanner according to the present embodiment. FIG. 2 is a diagram showing the difference between the images when the images are captured by the film scanner and the infrared data and the visible light data are compared and synthesized. FIG. 3 is a diagram showing how the dust / scratch area is corrected.
[0030]
In FIG. 2, it is assumed that a line sensor is arranged in the horizontal direction in the figure with respect to the film 2, and the line sensor (reading unit) is scanned (sub-scanned) in the vertical direction to capture an image. When dust and scratches 100 are present on the film 2 as shown in FIG. 2A, only dust and scratches as shown in FIG. 2B can be extracted by using infrared light (invisible light) for the illumination system. it can. Similarly, when an image is captured by illuminating with visible light, an image as shown in FIG. 2C is obtained.
[0031]
When the area of dust and flaws is determined from the image of FIG. 2B and is superimposed on the visible light image, if the scanning mechanism has a backlash as described above, the image is shifted as shown in FIG. 2D. It becomes a picture. That is, the area of the dust / scratch read in the visible light image does not match the area of the dust / scratch detected by the infrared light. FIG. 3 shows this in detail.
[0032]
FIG. 3A is an enlarged view of data between m1 pixel and m2 pixel for one dust in FIG. 2D, and a dotted line indicates a region determined to be dust / scratch by an infrared image, and a solid line. Is a visible light dust / scratch area. Whether the visible light image data is dust or scratch data is determined based on whether the image data is smaller than a certain threshold and whether the change rate of the image data is large at the boundary of the area. At this time, FIG. 9B shows the image data of the l (L) line. When the dotted line is infrared light data and the solid line is visible light data as in FIG. 3A, the image data is also shifted as shown in FIG. 3B due to the shift of the dust / scratch detection area.
[0033]
The purpose of the present embodiment is to correct FIG. 3 (b) as shown in FIG. 3 (c). This is to observe the infrared and visible light image data, and the image data falls to each other. This can be realized by matching a pixel that is present and a pixel that is rising. FIG. 3 is a diagram showing only a method of correcting data of one scan line in the dust / scratch region. By performing the above correction from the 1 (el) 1 line to the 1 (el) 2 line, the infrared image and the visible light are obtained. The displacement of the dust / scratch region due to the displacement of the image can be corrected.
[0034]
Hereinafter, a method of reading image information of the film 2 in the present embodiment will be described with reference to the flowchart of FIG. This image information reading method is stored as a program in a storage area in the film scanner control circuit 12 (detection means, comparison means). This program may be input-controlled from an external device, and may be stored in any form such as a floppy disk, CD-ROM, and MO.
[0035]
Steps 1 to 11 are the same as in the conventional example. Up to this point, image data of infrared light and visible light is accumulated, and the illumination lamp is turned off.
[0036]
(Step 12) Reset the L counter.
[0037]
(Step 13) It is determined whether or not the value of the L counter is ln. If not, the flow branches to step 14; otherwise, the flow branches to step 17.
[0038]
(Step 14) Attaching the line corresponding to the L counter in the sub-scanning direction of the image data, referring to the visible light image data in the vicinity of the dust / scratch area specified in Step 8, and changing the luminance change of the infrared image data A deviation between a large pixel and that of visible light image data is detected. As shown in FIG. 3B, it is determined whether or not the image data is smaller than a certain threshold value, that is, whether or not the image data is sufficiently blackened, and the difference between the falling pixel and the rising pixel is compared. It can be done by doing. In FIG. 3B, the falling pixel of the infrared image data corresponds to m3 and the rising pixel corresponds to m5, and the falling pixel of the visible light image data corresponds to m4 and the rising pixel corresponds to m6. Therefore, in step 14, a deviation between m3 and m4 and a deviation between m5 and m6 are detected. If these deviations exist, the flow branches to step 15;
[0039]
(Step 15) The rising pixel of the infrared image data is matched with that of the visible light image data, and the falling pixel of the infrared image data is matched with that of the visible light image data.
[0040]
(Step 16) The L counter is incremented.
[0041]
By performing the steps 13 to 16 by ln times, that is, the number of steps in the sub-scanning direction, it is possible to verify and correct the deviation of the image data in all the areas.
[0042]
(Step 17) A dust / scratch area is determined based on the image data of the infrared light corrected in step 15.
[0043]
(Step 18) The data of the new dust / scratch area determined in Step 17 is corrected by a known method.
[0044]
(Step 19) Output image data in which dust and scratches have been corrected.
[0045]
With the above configuration and flow, even if there is a shift between the infrared image and the visible light image, it is possible to accurately specify the dust / scratch area and obtain image data in which dust and scratches are satisfactorily corrected.
[0046]
《Second form》
As shown in FIG. 2, when there is a difference between the infrared image data and the visible light image data, the first embodiment corrects the dust / scratch region by matching the infrared image data with the visible light image data. In the present embodiment, an example will be described in which, when an image is misaligned, an area is corrected in a direction in which the dust / scratch area is enlarged.
[0047]
A second embodiment of the present invention will be described with reference to FIGS. Note that the image scanner of the present embodiment also assumes the film scanner described with reference to FIGS. 10 to 12 as described in the first embodiment, and the configuration thereof is as described above. Of course, the above configuration is merely an example, and the present invention is not limited to this configuration.
[0048]
FIG. 4 is a flow chart for explaining the operation of the film scanner for explaining the second embodiment, and FIGS. 5 and 6 are views showing how a dust / scratch area is corrected.
[0049]
FIG. 5 (a) shows the shift between the infrared image and the visible light image as in FIG. 3 (a). In FIG. 3 (a), the shift occurs only in the horizontal direction in the figure. On the other hand, FIG. 5A shows a state in which an image is shifted in the vertical direction.
[0050]
Crescent-shaped dust exists between 14'm3 'and 12'm5' in the visible light image, whereas it exists between 13'm2 'and 11'm4' in the infrared image. ing. That is, this shows a state in which the image shift has occurred by this amount. At this time, FIG. 6A shows the image information of the substantially middle line of the image of FIG. In FIG. 6A, a shift occurs between the infrared image data and the visible light image data as in FIG. 3B (the visible light image data is dust as in the first embodiment). The determination as to whether or not the data is flaw is made based on whether or not the image data is lower than a certain threshold value.)
[0051]
Next, when correcting this shift, in the present embodiment, the dust / scratch data is corrected in the direction in which it expands. FIG. 6B shows this state, and the rising edge of the infrared image data is corrected from m5 to m6. The above correction is performed in the dust / scratch region (from l1 'to l3') of the infrared image.
[0052]
The new dust / scratch area thus obtained is as shown in FIG. However, in the sub-scanning direction; l1 'to l3' in FIG. 5A, the dust / scratch area can be corrected by the above-described correction method so as to include the dust and flaws in the visible light image. At 14 ', dust data of the visible light image remains. Therefore, by slicing the image in the vertical direction and performing the same processing, it is possible to specify a dust / scratch region that completely includes the dust data of the visible light image. FIGS. 6C and 6D show this state. As shown in the figure, the rise of the infrared image data is corrected so as to coincide with the rise of the visible light image data. This correction is performed in the dust / scratch area (m2 'to m4') of the infrared image to correct the dust / scratch area. In this way, a dust / scratch region completely including the dust data of the visible light image could be created (FIG. 5C).
[0053]
Hereinafter, a method of reading image information of the film 2 according to the second embodiment will be described with reference to the flowchart of FIG. This image information reading method is stored as a program in a storage area in the film scanner control circuit 12. This program may be input-controlled from an external device, and may be stored in any form such as a floppy disk, CD-ROM, and MO.
[0054]
Steps 21 to 31 are the same as steps 1 to 11 in the first embodiment. Up to this point, image data of infrared light and visible light is accumulated, and the illumination lamp is turned off.
[0055]
(Step 32) The L counter is reset.
[0056]
(Step 33) It is determined whether or not the value of the L counter is ln. If not, the flow branches to step 34;
[0057]
(Step 34) Refer to the visible light image data in the vicinity of the dust / scratch region specified in step 28 for the line corresponding to the L counter in the sub-scanning direction of the image data, and determine the luminance change of the infrared image data. A deviation between a large pixel and that of visible light image data is detected. As shown in FIG. 6B, it is determined whether or not the image data is smaller than a certain threshold value, that is, whether or not the image data is sufficiently blackened, and the difference between the falling pixel and the rising pixel is compared. It can be done by doing. In FIG. 6B, the falling pixel of the infrared image data corresponds to m3 and the rising pixel corresponds to m5, and the falling pixel of the visible light image data corresponds to m4 and the rising pixel corresponds to m6. Therefore, in step 34, a deviation between m3 and m4 and a deviation between m5 and m6 are detected. If these deviations exist, the flow branches to step 35; otherwise, the flow branches to 36.
[0058]
(Step 35) The rising pixel of the infrared image data is matched with that of the visible light image data.
[0059]
(Step 36) The L counter is incremented.
[0060]
By performing Steps 33 to 36 above by ln times, that is, by the number of steps in the sub-scanning direction, it is possible to verify and correct the deviation of the image data in all the areas.
[0061]
(Step 37) The M counter is reset.
[0062]
(Step 38) It is determined whether or not the value of the M counter is mn. If not, the flow branches to step 39; otherwise, the flow branches to step 42.
[0063]
(Step 39) A line corresponding to the M counter in the main scanning direction of the image data is referred to the visible light image data near the dust / scratch area specified in step 28, and the luminance change of the infrared image data is determined. A deviation between a large pixel and that of visible light image data is detected. As shown in FIG. 6C, it is determined whether or not the image data is smaller than a certain threshold, that is, whether or not the image data is sufficiently blackened, and the difference between the falling line and the rising line is compared. It can be done by doing. In FIG. 6C, the falling lines of the infrared image data and the visible light image data do not match, and the rising lines do not match. In step 39, this deviation is detected. If any of these deviations exist, the process branches to step 40;
[0064]
(Step 40) Match the rising pixels of the infrared image data with those of the visible light image data.
[0065]
(Step 41) The M counter is incremented.
[0066]
By performing the steps 38 to 41 mn times, that is, several times in the main scanning direction, the deviation of the image data in all the areas can be verified and corrected.
[0067]
(Step 42) A dust / scratch area is determined based on the image data of the infrared light corrected in step 40.
[0068]
(Step 43) The data of the new dust / scratch area determined in step 42 is corrected by a known method.
[0069]
(Step 44) Output image data in which dust and scratches have been corrected.
[0070]
With the above configuration and flow, even if there is a shift between the infrared image and the visible light image, it is possible to accurately specify the dust / scratch area and obtain image data in which the dust and the scratch are corrected well.
[0071]
《Third form》
As shown in FIG. 2, when there is a difference between the infrared image data and the visible light image data, the first embodiment corrects the dust / scratch region by matching the infrared image data with the visible light image data. In the second embodiment, an example in which the area is corrected in the direction in which the dust / scratch area expands has been described. However, the area correction will be described below as a third embodiment more easily than in these embodiments. An example is shown in which the calculation time is shortened.
[0072]
A third embodiment of the present invention will be described with reference to FIGS. It should be noted that the image reading apparatus according to the present embodiment also assumes the film scanner shown in FIGS. 10 to 12 as described in the first embodiment, and the configuration is as described above. Of course, the above configuration is merely an example, and the present invention is not limited to this configuration.
[0073]
FIG. 7 is a flowchart for explaining the operation of the film scanner for explaining the third embodiment, and FIGS. 8 and 9 are views showing a state of correcting a dust / scratch area.
[0074]
FIG. 8A shows a shift between the infrared image and the visible light image as in FIG. 5A. The rod-shaped dust or scratches are displaced diagonally to the upper left. As described above, if the shift is caused by the play of the scanning mechanism, the shift should be constant throughout the image. Since it is rare that the shift amount differs for each line, the shift is almost corrected by measuring the shift of one line of the same image and moving the infrared image data by that amount. This embodiment shows an example.
[0075]
FIG. 8A is an enlarged view of one dust in the image, and dust data of the infrared image exists between the sub-scanning directions l1 "and l2". FIG. 9 (a) shows the data on the substantially middle line (l line) between l1 "and l2", and m2 "-m1" or m4 "-m3" in this data is the difference data. Therefore, m = m2 ″ −m1 = m4 ″ −m3 ″ is defined and the infrared image data is shifted by m and corrected (FIG. 9 (b). This is performed for all the image data, and the infrared image data is corrected. (FIG. 8B) A dust / scratch region in which the dust data of the infrared image and the dust data of the visible light image almost coincide was created.
[0076]
Hereinafter, a method of reading image information of the film 2 in the present embodiment will be described with reference to the flowchart of FIG. This image information reading method is stored as a program in a storage area in the film scanner control circuit 12. This program may be input-controlled from an external device, and may be stored in any form such as a floppy disk, CD-ROM, and MO.
[0077]
Steps 51 to 61 are the same as steps 1 to 11 shown in FIG. 1. At this point, image data using infrared light and visible light is accumulated, and the illumination lamp is turned off.
[0078]
(Step 62) The representative data is arbitrarily selected from the dust / scratch area created in step 58, and the shift amount is obtained by the shift measurement method described above.
[0079]
(Step 63) The image data outside the amount of blur determined in step 62 is corrected. Then, a new dust / scratch area is created from the corrected infrared image data.
[0080]
(Step 64) The data of the new dust / scratch area created in step 63 is corrected by a known method.
[0081]
(Step 65) Output image data in which dust and scratches have been corrected.
[0082]
With the above configuration and flow, even if there is a shift between the infrared image and the visible light image, it is possible to accurately specify the dust / scratch area and obtain image data in which dust and scratches have been well corrected by a simple method. became.
[0083]
【The invention's effect】
As described above, according to the present invention, a high-quality read image can be obtained.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an operation of a film scanner according to a first embodiment.
FIG. 2 is a conceptual diagram of image capture by infrared light and visible light.
FIG. 3 is a diagram illustrating a method for correcting image data according to the first embodiment.
FIG. 4 is a flowchart illustrating an operation of the film scanner according to the second embodiment.
FIG. 5 is a diagram illustrating a method for correcting image data according to the second embodiment.
FIG. 6 is a diagram illustrating a method for correcting image data according to the second embodiment.
FIG. 7 is a flowchart illustrating an operation of the film scanner according to the third embodiment.
FIG. 8 is a diagram illustrating a method for correcting image data according to the third embodiment.
FIG. 9 is a diagram illustrating a method for correcting image data according to the third embodiment.
FIG. 10 is a perspective view of a main part of a conventional film scanner.
11 is a schematic configuration diagram of the film scanner shown in FIG.
FIG. 12 is a block diagram showing a circuit configuration of the film scanner shown in FIG.
FIG. 13 is a flowchart for controlling the operation of the film scanner shown in FIG.
FIG. 14 is a schematic diagram showing the influence of dust and scratches.
[Explanation of symbols]
1 Film carriage
2 Film
3 lamps
4 mirror
5 Optical system
6 line sensor
7 Motor
8 sensors
9 Optical axis
10a Infrared cut filter
10b Visible light cut filter
11 Filter motor
12 Control circuit

Claims (9)

Abnormality detecting means for detecting an abnormal region on the document from invisible light image data obtained by scanning the document while irradiating the invisible light,
In the visible light image data obtained by scanning the original while irradiating the visible light, the visible light image corresponding to the abnormal region, and the shift between the invisible light image corresponding to the abnormal region in the invisible light image data. A shift detecting unit for detecting, a correcting unit for correcting a shift between the visible light image and the invisible light image detected by the shift detecting unit,
An image reading apparatus comprising: 2. The image reading apparatus according to claim 1, wherein the correction unit corrects the visible light image and at least a part of the invisible light image so as to substantially coincide with each other in accordance with a detection result by the displacement detection unit. 3. The image reading apparatus according to claim 1, further comprising a scanning unit configured to scan the document. 4. The image reading apparatus according to claim 1, wherein the abnormal region is a region on the document with dust and / or scratches. 5. An abnormality detection step of detecting an abnormal area on the original from invisible light image data obtained by scanning the original while irradiating the invisible light; and a visible light obtained by scanning the original while irradiating the visible light In the visible light image corresponding to the abnormal area in the image data, a shift detection step of detecting a shift between the invisible light image corresponding to the abnormal area in the invisible light image data,
A correction step of correcting a shift between the visible light image and the invisible light image detected by the shift detection step,
An image reading method, comprising: 6. The image reading method according to claim 5, wherein in the correcting step, the visible light image and the invisible light image are corrected so that at least a part thereof substantially coincides with each other in accordance with a detection result of the shift detecting step. 7. The image reading method according to claim 5, further comprising a scanning step of scanning the document by a scanning unit. 8. The image reading method according to claim 5, wherein the abnormal area is an area having dust and / or scratches on the document. 9. A storage medium storing a program for causing an image reading apparatus to execute the image reading method according to claim 5.

Images