JP2001223894A - Picture processor, picture processing method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture processor which prevents a defective pixel due to dirts and scratchs from being viewed and can improve the quality of a picture. SOLUTION: When a defective pixel area is substituted by a normal pixel pattern, it is discriminated whether the pixel is normal or not (S1001). When the pixel is normal, it is discriminated whether the pixel has a color close to the pixels at both ends of the defective pixel area or not (S1002). When the color is close, it is discriminated whether the pixel is in the end of the picture or not (S1003). When it is not in the end of the picture, the pixel is detected as the normal pixel pattern (S1004). Then, it is discriminated whether the defective pixel area is larger than the detected normal pixel pattern or not (S1005). When it is larger, the next pixel is set to be the pixel (S1007) and a similar processing is repeated until the normal pixel pattern becomes larger than the defective pixel area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads a developed film photographed by, for example, a silver halide camera,
The present invention relates to an image processing apparatus, a method, and a storage medium for correcting (correcting) pixel data of a digital image obtained by a film scanner that performs appropriate gradation conversion and outputs the result.

[0002]

2. Description of the Related Art Conventionally, image information recorded on a film is read by a line sensor, and RGB output voltages of the line sensor are amplified by an analog amplifier.
2. Description of the Related Art A film scanner that converts a digital signal into a digital signal using a / D converter, performs various types of digital image processing, and outputs the digital signal is known.

In such a film scanner, as the resolution of the film scanner itself increases, more detailed information on the film can be obtained. Has become a problem.

As a method for solving this problem, Japanese Patent Publication No.
In -78991, visible information and infrared information on a film are separately obtained by switching a filter,
There has been proposed a method of detecting the position of dust or a scratch using the obtained infrared information, and interpolating a defective pixel due to the dust or the scratch with reference to pixel information around the detected position of the dust or the scratch.

[0005]

However, in the above-mentioned conventional method, for example, even if the image has a relatively uniform level in appearance such as the sky, the signal level fluctuates due to the influence of noise or the like in pixel units. If this is simply interpolated by surrounding pixels, an unnatural difference occurs in the signal level between the pixel affected by dirt and scratches and the surrounding pixels, which often gives an unnatural impression to the corrected image. Was given.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus, method, and storage medium that can increase the quality of an image by making defective pixels invisible due to dust or scratches invisible.

[0007]

To achieve the above object, an image processing apparatus according to a first aspect of the present invention comprises a defective pixel detecting means for scanning an image to detect a defective pixel which needs to be corrected. A defective pixel area detecting means for detecting a defective pixel area in which the detected defective pixels are continuous; a normal pixel detecting means for detecting a normal pixel which does not need correction from around the detected defective pixel area; Normal pixel area detecting means for detecting a normal pixel area in which the detected normal pixels continue, and replacing means for replacing the defective pixel area with the detected normal pixel area.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the defective pixel area detecting means detects the defective pixel area in which the detected defective pixels are continuous in the horizontal direction. It is characterized by doing.

According to a third aspect of the present invention, in the image processing apparatus according to the first aspect, the defective pixel area detecting means detects the defective pixel area in which the detected defective pixels are vertically continuous. It is characterized by doing.

In the image processing apparatus according to a fourth aspect, in the image processing apparatus according to the first aspect, the defective pixel area detecting means includes the defective pixel in which the detected defective pixel is continuous in a horizontal direction and a vertical direction. Detect each area,
The defective pixel area to be replaced by the replacement means is determined according to the number of pixels of the detected defective pixel area.

In the image processing apparatus according to a fifth aspect, in the image processing apparatus according to the first aspect, the defective pixel area detecting means includes the defective pixel in which the detected defective pixel is continuous in a horizontal direction and a vertical direction. Detect each area,
A defective pixel area to be replaced by the replacement means is determined according to a color component of a normal pixel located around the detected defective pixel area.

According to a sixth aspect of the present invention, in the image processing apparatus according to the first aspect, the defective pixel area detecting means includes a normal pixel located on both sides of the detected defective pixel area in the sub-scanning direction. Is treated as a predetermined number of defective pixels, thereby expanding the defective pixel area.

In the image processing apparatus according to a seventh aspect, in the image processing apparatus according to the first aspect, the replacement unit includes a predetermined number of pixels constituting a defective pixel area detected by the defective pixel area detection unit. In the following case, the defective pixel area is replaced with the normal pixel area.

According to an eighth aspect of the present invention, in the image processing apparatus according to the first aspect, the replacement means includes a normal pixel around a defective pixel area detected by the defective pixel area detection means. In this case, the defective pixel area is replaced with the normal pixel area.

According to a ninth aspect of the present invention, in the image processing apparatus according to the first aspect, the replacement means includes a color component of a defective pixel area detected by the defective pixel area detection means, and a color component of the defective pixel area. When the difference from the color component of a normal pixel located around the area is equal to or smaller than a predetermined value, the defective pixel area is replaced with the normal pixel area.

According to a tenth aspect of the present invention, in the image processing apparatus according to the first aspect, the normal pixel area detecting means sequentially focuses attention from an end of the defective pixel area detected by the defective pixel area detecting means. A pixel is scanned, a color component of the target pixel is compared with a color component of the defective pixel region, and it is determined whether or not the target pixel is adopted as a normal pixel in the normal pixel region.

In the image processing apparatus according to the eleventh aspect, in the image processing apparatus according to the first aspect, the normal pixel area detecting means focuses on the defective pixel area detected by the defective pixel area detecting means in order from an end of the defective pixel area. A pixel is scanned, and if the target pixel has not reached the end of the image, the target pixel is adopted as a normal pixel in the normal pixel region.

In the image processing apparatus according to a twelfth aspect, in the image processing apparatus according to the first aspect, the normal pixel area detecting means sequentially focuses attention from an end of the defective pixel area detected by the defective pixel area detecting means. A pixel is scanned, and if the target pixel is not a defective pixel, the target pixel is adopted as a normal pixel in the normal pixel region.

According to a thirteenth aspect of the present invention, in the image processing apparatus according to the first aspect, the replacement means includes:
The number of pixels of the plurality of normal pixel regions located around the defective pixel region is compared, and a normal pixel region used for the replacement is determined based on the comparison result.

According to a fourteenth aspect of the present invention, in the image processing apparatus according to the first aspect, the replacing means comprises:
The method is characterized in that a difference between the color components of the plurality of normal pixel regions located around the defective pixel region is compared, and a normal pixel region used for the replacement is determined based on the comparison result.

In the image processing method according to the present invention, the step of scanning an image to detect a defective pixel that needs to be corrected, the step of detecting a defective pixel area in which the detected defective pixel is continuous, Detecting a normal pixel that does not require correction from around the detected defective pixel area; detecting a normal pixel area where the detected normal pixel is continuous; and detecting the defective pixel in the detected normal pixel area. Replacing the region.

A storage medium according to claim 16, wherein the storage medium is executed by a computer in an image processing apparatus and stores a program for correcting an image, wherein the program scans the image to detect defective pixels that need to be corrected. Detecting, detecting a defective pixel region in which the detected defective pixel is continuous, detecting normal pixels that do not need correction from around the detected defective pixel region, and detecting the detected defective pixel. The method includes a step of detecting a normal pixel area in which normal pixels continue, and a step of replacing the defective pixel area with the detected normal pixel area.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the image processing apparatus, method and storage medium of the present invention will be described. The image processing apparatus according to the present embodiment is applied to a film scanner using a negative film as a document.

[First Embodiment] FIG. 1 is a diagram showing a configuration of a film scanner. In the figure, reference numeral 101 denotes a lamp for illuminating a film, which is driven by a lamp driving circuit 113 controlled by a CPU 119.

Reference numeral 102 denotes a film folder for holding a film, which is movable in the direction of arrow A in FIG. The sub-scanning motor 108 has a CPU 119
Driven by a motor drive circuit 112 controlled by The position of the film folder 102 is detected by the sub-scanning position detection sensor 107, and the initial position of the film folder 102 is obtained.

Reference numeral 103 denotes a filter switching device for switching between an infrared light cut filter a and a visible light cut filter b, which is movable in the direction of arrow B in the figure by a filter switching motor 109. The filter switching motor 109 has a C
Filter switching drive circuit 1 controlled by PU 119
11 driven. The filter switching state is determined by the filter switching detection sensor 104 in the CPU 119.
Conveyed to.

In the present embodiment, a stepping motor is used as the sub-scanning motor 108 and the filter switching motor 109, and a photo-interrupter is used as the sub-scanning position detecting sensor 107 and the filter switching detecting sensor 104.

Reference numeral 105 denotes an imaging lens which forms an image of light radiated from the lamp 101 and transmitted through the film on a CCD line sensor (hereinafter simply referred to as a CCD) 106. CCD 106 is controlled by CPU 119
It is driven by the CD drive circuit 110 and has an electronic shutter function that can control the timing of outputting the charge stored in the CCD. The CCD 106 is the film folder 102
Is mounted in a direction perpendicular to the movement direction A (vertical direction in the drawing), and due to this positional relationship, C
The main scanning direction, which is the longitudinal direction (vertical direction in the drawing) of the CD 106, and the sub-scanning direction, which is the moving direction of the film folder 102, have an orthogonal relationship.

Reference numeral 114 denotes an analog processing circuit which performs gain setting and clamp processing of an analog image signal output from the CCD 106, and is capable of independently amplifying RGB signals by an analog amplifier. An A / D converter 115 converts an analog signal output from the analog processing circuit 114 into a digital signal.

Reference numeral 116 denotes a digital image processing unit for processing an image signal digitized by the A / D converter 115. The digital image processing unit 116 performs a negative / positive conversion and white balance adjustment of an input signal by performing a negative / positive conversion of an input signal. It has a gradation conversion curve creation unit that creates a gradation conversion curve for adjusting to a fine gradation. The image processing unit 116 may be constituted by a gate array, or a DSP having a CPU and a ROM.
And the like. In the present embodiment, the case where the image processing unit 16 is configured by a microcomputer unit such as a DSP and a CPU (not shown) executes a control program stored in a ROM will be described.

Reference numeral 117 denotes a line buffer for temporarily storing image data. Reference numeral 118 denotes an interface unit for connecting to an external device such as a personal computer (personal computer). Reference numeral 119 denotes a ROM for storing a program (software) for controlling the operation of the entire film scanner, and a system controller (hereinafter simply referred to as CPU) having a built-in CPU for performing various operations in accordance with instructions from external devices based on the program. ).

Image data is obtained by communication processing using software in the system controller 119 (hereinafter referred to as firmware software) and software (hereinafter referred to as driver software) for operating a film scanner from an external device such as a personal computer. Output to external device.

FIG. 2 is a diagram showing a method for detecting dust and scratches on a film by infrared light. FIG. 4A shows an output signal for one line output from the CCD 106 when the negative film is irradiated with visible light. FIG. 3B shows an output signal for one line output from the CCD 106 when the negative film is irradiated with infrared light.

When an infrared cut filter a is arranged on the optical path by the filter switching device 103, as shown in FIG. 4A, visible light is irradiated on the film, and the change of the output signal of the CCD 106 due to dust and scratches. And CCD1 with image
It is difficult to discriminate the change of the output signal from the output signal No. 06.

On the other hand, when the visible light cut filter b is arranged on the optical path by the filter switching device 103, infrared light is irradiated onto the film as shown in FIG.
Since there is almost no change in the output signal of the CCD 106 due to an image, a change in the output signal of the CCD 106 due to dust or scratch mainly appears, and it is possible to detect the position of dust or scratch on the film by setting a threshold value. .

This detection method utilizes the characteristics of the transmittance with respect to the wavelength of the film. Irradiating the film with infrared light causes signal changes due to dust or scratches on the film, regardless of the image information recorded on the film, because ordinary films have high transmittance to infrared light. Information can be obtained.

In FIG. 4B, two thresholds, threshold 1 and threshold 2, are set in order to select an optimal correction process according to the amount of infrared light attenuation due to dust or scratches on the film. I have. As a method of calculating the threshold value, for example, a method of calculating the maximum value of the infrared signal level, setting a threshold value 1 at a position of a predetermined ratio from the calculated value, and setting a threshold value 2 at a position of a smaller ratio than that is used. be able to. Although the threshold value was calculated using the maximum value of the infrared signal level as the reference value, an average value or a median value may be used as the reference value instead of the maximum value, and the calculation method is not particularly limited.

Next, a description will be given of a process of correcting a defective pixel area due to dust or scratches. FIG. 3 is a flowchart showing a procedure of correcting a defective pixel area due to dust or scratches performed in the image processing unit 116. This processing program is stored in the ROM in the image processing unit 116, and is also executed by the CPU in the image processing unit 116.

The infrared light cut filter a and the visible light cut filter b are alternately arranged on the optical axis by the filter switching device 103, and the light transmitted through the negative film is read by the CCD 106 by scanning the negative film. The visible image and the infrared image output as digital signals by the A / D converter 115 are processed by the image processing unit 1.
16 (steps S301, S302).

A threshold for detecting a defective pixel due to dust or a scratch from the infrared image is calculated (step S303). Subsequently, a process of correcting a shift between the visible image and the infrared image is performed (step S304). As described above, the infrared image and the visible image are transferred from the film folder 102 to the sub-scanning motor 1.
08 to move in the direction of arrow A in the figure.
Although read by D106, in this embodiment, 1
Since the visible image and the infrared image are separately acquired by one reciprocation, an error due to the feeding accuracy is expected to occur. Since the correction of defective pixels due to dust or scratches is performed on a pixel-by-pixel basis, it is necessary to correct as much as possible the deviation of several pixels between the visible image and the infrared image due to this error.

FIG. 4 is a diagram showing a shift correction process. First, a predetermined number of defective pixel areas are detected in the sub-scanning direction using an infrared image (see FIG. 3A). Since this is a correction process for detecting a shift between the visible image and the infrared image due to the feeding accuracy, it is based on the premise that the shift direction is only the sub-scanning direction.

The coordinates of the detected defective pixel area in the infrared image are obtained (see FIG. 3B). Then, the visible image and the infrared image are shifted by a predetermined number of pixels in the sub-scanning direction (the direction of arrow a in the figure) by a predetermined number of pixels (see (C) in the figure), and the visible image and the infrared image corresponding to the coordinates of the defective pixel area are obtained. Is calculated. When the sum of the calculated signal values is the minimum, it is considered that the defective pixel areas of the visible image and the infrared image match, and the number of shifted pixels is stored as the number of shifted pixels. This is based on the idea that the missing pixel region of the visible image will have a lower signal value than the surrounding pixels. Note that the predetermined number when detecting the defective pixel area and the predetermined number of pixels when shifting the visible image and the infrared image are determined to appropriate values depending on whether correction accuracy or required time is prioritized.

After the shift in the sub-scanning direction between the visible image and the infrared image has been corrected by performing the shift correction processing in step S304, the first correction processing as correction processing is performed (step S304). S305). The correction process 1 is to calculate a signal value of a defective pixel region of a visible image from an attenuation amount of the defective pixel region in the infrared image. This is because the amount of attenuation of the infrared image in the defective pixel area is relatively small,
This is an effective correction process when the visible signal value of the defective pixel region remains in the visible image, and is used for a defective pixel region in which the signal level of the infrared image falls between the threshold 1 and the threshold 2 in FIG. Done.

As described above, after the defective pixel area having a relatively small amount of attenuation is corrected by the correction processing 1 of step S305, the loss of the infrared signal level attenuated to the threshold 2 or less that could not be completely corrected by the correction processing 1. A correction process 2 for correcting the pixel area is performed (step S306). In the present embodiment, since the defective pixel area is replaced using a normal pixel area (normal pixel pattern) located around the defective pixel area, the correction processing 2 is referred to as pattern replacement.

FIG. 5 is a flowchart showing the pattern replacement processing procedure in step S306. First, scanning is started in units of pixels in the horizontal direction starting from the upper left pixel of the infrared image (step S501). Then, the defective pixel area and the normal pixel pattern are detected and replaced (step S502).

Scanning is again performed in the vertical direction on a pixel-by-pixel basis starting from the upper left pixel of the image (step S503). Similarly, replacement is performed by detecting a defective pixel area and a normal pixel pattern (step S504). Thereafter, the process ends.

FIG. 6 shows steps S502 and S
504 is a flowchart illustrating a procedure for detecting and replacing a defective pixel area in 504. FIG. 7 is a diagram illustrating detection of a defective pixel area. First, a defective pixel (defective pixel 1 in FIG. 7) is detected (step S601). A continuous defective pixel is detected from the detected defective pixel 1 (the defective pixels 2 to 5 in FIG. 7), and these are defined as a defective pixel area.

At this time, it is assumed that the shift between the infrared image and the visible image has been corrected by the above-described shift correction. Even if the shift is not corrected, as shown in FIG. Depending on the accuracy, by expanding the defective pixel area by n pixels on both sides in the sub-scanning direction from the actually detected pixel area, the non-detection of the defective pixel area due to the displacement can be prevented. FIG. 8 is a diagram showing an enlarged defective pixel area.

If a defective pixel area is detected in step S601, it is checked whether or not the defective pixel area is an area where pattern replacement is possible (step S60).
2). That is, if even one of the following check items is not satisfied, it is determined that pattern replacement is impossible. The defective pixel area is equal to or less than a predetermined number of pixels. Normal pixels exist at both ends of the defective pixel area. The normal pixels existing at both ends of the defective pixel area are near colors.

The check item is provided to increase the processing time when the defective pixel area is too large. The predetermined number of pixels is determined in consideration of the processing time. In the check item, since the pattern replacement according to the present embodiment is a process of performing replacement using the normal pixel patterns at both ends of the defective pixel area, normal pixels must be present at both ends of the defective pixel area. The check item is such that when the normal pixels located at both ends of the defective pixel are not close to each other, the corrected pixel gives a distinctly different impression from the surrounding pixels when performing pattern replacement so that the replacement result does not have an undesirable result. It was provided.

FIG. 9 is a flowchart showing the pattern check processing procedure in step S602. First,
It is determined whether the number of defective pixels is equal to or less than a predetermined number of pixels (step S901). If the number of pixels is equal to or smaller than the predetermined number, it is determined whether or not normal pixels exist at both ends of the defective pixel area (step S902). If a normal pixel exists, it is determined whether or not the normal pixels existing at both ends of the defective pixel area have near colors (step S903). If the color is close, it is determined that pattern replacement is possible (step S90).
4), end the process. On the other hand, if the number of pixels is not equal to or less than the predetermined number of pixels in step S901, if there is no normal pixel in step S902, or if the normal pixels are not close colors in step S903, it is determined that pattern replacement is impossible (step S904), and the process is performed. finish.

In this way, it is checked whether or not the defective pixel area can be replaced with a pattern. If it is determined that the defective pixel area can be replaced, a normal pixel pattern is formed from both ends of the defective pixel area into the maximum defective pixel area. The number of detected pixels is detected (step S603). When the scanned pixel (target pixel) satisfies all of the following check items (1) to (4), it is detected as a normal pixel pattern. It is a normal pixel. The color is close to the pixels at both ends of the defective pixel area. Not at the edge of the image.

Under the conditions, since a normal pixel pattern is detected, naturally, when a defect is detected during scanning, the detection of the normal pixel pattern is stopped. Under the conditions, if the detected normal pixel pattern is not close to the pixels forming the defective pixel area, the corrected pixel gives a distinctly different impression from the surrounding pixels when performing pattern replacement, which is not preferable as replacement. is there. Under the condition, if the end of the image is reached, it is impossible to detect any more normal pixels, so that the detection is stopped.

FIG. 10 is a flowchart showing the procedure for detecting a normal pixel pattern in step S603. First, it is determined whether or not the pixel of interest is a normal pixel (step S1001). If the pixel of interest is a normal pixel, it is determined whether or not the pixel at both ends of the defective pixel area is close in color (step S1002). If the target pixel is close to the pixels at both ends of the defective pixel area, it is determined whether the target pixel is not at the end of the image (step S1003). If not, the target pixel is detected as a normal pixel pattern (step S1004). Further, it is determined whether or not the defective pixel area is larger than the detected normal pixel pattern (step S1005). If the defective pixel area is larger, the next pixel is set as a target pixel (step S1007), and step S10 is performed.
It returns to the process of 01.

On the other hand, if the target pixel is not a normal pixel in step S1001, and if the target pixel is not close to the pixels at both ends of the defective pixel area in step S1002,
If the target pixel is located at the end of the image in step 1003, or if the size of the normal pixel pattern is larger than the defective pixel area in step S1005, the detection is stopped (step S1005).
1006), the process ends.

After the normal pixel patterns are detected at both ends of the defective pixel area in this way, the defective pixel area is replaced using these normal pixel patterns (step S60).
4), end the process. At this time, when a normal pixel pattern is detected in only one of both ends of the defective pixel area, replacement is performed using the normal pixel pattern. Also,
When normal pixel patterns are detected at both ends of the defective pixel area, replacement is performed with a normal pixel pattern having a large number of pixels. FIG.
FIG. 1 is a diagram showing an example in which replacement is performed with a normal pixel pattern having a large number of pixels. Further, when normal pixel patterns are detected at both ends of the defective pixel area and the number of pixels of both pixel patterns is the same, replacement is performed with normal pixel patterns having a small maximum level difference between the pixels constituting the normal pixel pattern.
FIG. 12 is a diagram illustrating an example in which replacement is performed with a normal pixel pattern having a small maximum level difference. Thus, the normal pixel pattern is determined, and the defective pixel area is filled.

As described above, after performing the correction process twice on the defective pixel area, the averaging process is performed on the corrected pixels (step S307), and an image is output without discomfort with the peripheral pixels. (Step S308). Thereafter, the correction processing ends.

The film scanner of this embodiment acquires a visible image and an infrared image of a negative film, detects a defective pixel area due to dirt or a scratch present on the negative film, and performs a correction process when performing a correction process. By detecting a normal pixel pattern in which normal pixels continue, and replacing the defective pixel area with the detected normal pixel pattern, it is possible to perform optimal image correction in which dust and scratches are completely invisible.

In this embodiment, as a method of detecting a defective pixel area, a method of performing scanning in the horizontal direction (sub-scanning direction) and then performing scanning in the vertical direction (main scanning direction) has been described. After scanning in the vertical direction, scanning in the horizontal direction may be performed. Further, a detection method by scanning only in the horizontal direction or scanning only in the vertical direction is possible depending on the balance between the accuracy of correction and the required calculation time.

[Second Embodiment] The configuration of a film scanner according to a second embodiment is the same as that of the first embodiment, so that the description thereof is omitted, and here, the second embodiment is different from the first embodiment. Only the pattern replacement processing will be described.

FIG. 13 is a flowchart showing a pattern replacement processing procedure in the second embodiment. First, scanning is started in units of pixels in the horizontal direction starting from the upper left pixel of the infrared image (step S1301). The defective pixel area and the normal pixel pattern are detected and replaced (step S1302), and the process ends. Here, step S1
The process of detecting a defective pixel area and replacing a normal pixel pattern at 302 will be described with reference to FIG.

That is, the defective pixel area is detected (step S601), and the infrared image is scanned pixel by pixel to detect a defective pixel whose infrared signal is lower than the threshold value 2 in FIG. 2 (defective pixel in FIG. 14). 1). FIG. 14 is a diagram illustrating detection of a defective pixel area. Defective pixels continuous in both the horizontal and vertical directions are detected from the detected defective pixel 1 (defective pixels 2 to 5, II to VI in FIG. 14), and these continuous defective pixel areas are respectively referred to as a defective pixel area A and a defective pixel area. The pixel area is assumed to be B.

The numbers of pixels constituting the defective pixel area A and the defective pixel area B are compared, and a defective pixel area having a small number of pixels is adopted as a replacement defective pixel area. At this time, it is assumed that the shift between the infrared image and the visible image has been corrected by the shift correction described in the first embodiment. However, depending on the accuracy of the shift correction, the defective pixel area is actually detected. By making n pixels larger on both sides in the sub-scanning direction or the main scanning direction than the shifted pixel region, that is, by enlarging the pixel region, it is possible to prevent a missing pixel region from being undetected due to a shift.

When a defective pixel area is detected, the processing after step S602 for checking whether or not the defective pixel area can be replaced with a pattern is the same as that in the first embodiment.

As described above, in the second embodiment, as a method of detecting a defective pixel area, the defective pixel is detected by scanning in the horizontal direction, and the detected defective pixel is used as a starting point in the horizontal and vertical directions. Although a defective pixel is detected, a vertical pixel may be scanned instead of the horizontal direction to detect a defective pixel serving as a starting point.

Further, the following may be performed when determining the defective pixel area for replacement. FIG. 15 is a diagram showing normal pixels located at both ends of the defective pixel area A and the defective pixel area B. When the normal pixels A, B, C, and D are all close colors, the number of pixels constituting each of the defective pixel area A and the defective pixel area B is compared, and the defective pixel area having a small number of pixels is determined as the replacement defective pixel area. adopt. On the other hand, if all of the normal pixels A, A, C, and D are not close colors, it may be determined at this point that the target defective pixel area cannot be replaced with a pattern, and detection of the next defective pixel may be started.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the embodiments, and the functions described in the claims or the configurations of the embodiments are not limited to the embodiments. Any configuration can be applied as long as it has the function that it has. For example, the present invention is not limited to a film scanner and can be applied to a copying machine, a facsimile machine, a digital camera, and the like.

Further, the software configuration and the hardware configuration of the above embodiment can be replaced as appropriate. Further, the present invention may be applied to a case where the claims or the whole or a part of the configuration of the embodiment forms one device or is combined with another device, It may be an element constituting the device.

The present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading out a storage medium storing a program represented by software for achieving the present invention into a system or an apparatus, the system or the apparatus can enjoy the effects of the present invention.

FIG. 16 shows an image processing unit 11 as a storage medium.
6 is a diagram showing a memory map of a ROM in 6. FIG. The ROM stores a correction processing program module shown in the flowchart of FIG. 3, a pattern replacement processing program module shown in the flowchart of FIG. 5, a defective pixel area detection and replacement processing program module shown in the flowchart of FIG. 6, and a flowchart shown in FIG. A pattern check processing program module, a normal pixel pattern detection processing program module shown in the flowchart of FIG. 10, a pattern replacement processing program module shown in the flowchart of FIG. 13, and the like are stored.

The storage medium for supplying the program module is not limited to ROM, but may be, for example, a floppy disk, hard disk, optical disk, magneto-optical disk,
A D-ROM, a CD-R, a DVD, a magnetic tape, a nonvolatile memory card, or the like can be used.

[0072]

According to the present invention, when a defective pixel area due to dust or scratches is detected and correction processing is performed, a normal pixel area in which surrounding normal pixels are continuous is detected, and the detected normal pixel area is detected. By replacing the defective pixel area, it is possible to perform an optimal image correction in which dust and scratches are completely invisible. In this way, the quality of an image can be enhanced by making defective pixels invisible due to dust or scratches invisible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a film scanner.

FIG. 2 is a diagram illustrating a method for detecting dust and scratches on a film by infrared light.

FIG. 3 is a flowchart showing a procedure of correcting a defective pixel area due to dust or scratches performed by an image processing unit;

FIG. 4 is a diagram illustrating a shift correction process.

FIG. 5 is a flowchart illustrating a pattern replacement processing procedure in step S306.

FIG. 6 is a flowchart illustrating a procedure of detecting and replacing a defective pixel area in steps S502 and S504.

FIG. 7 is a diagram showing detection of a defective pixel area.

FIG. 8 is a diagram illustrating an enlarged defective pixel area.

FIG. 9 is a flowchart illustrating a pattern check processing procedure in step S602.

FIG. 10 is a flowchart illustrating a normal pixel pattern detection processing procedure in step S603.

FIG. 11 is a diagram illustrating an example of performing replacement with a normal pixel pattern having a large number of pixels.

FIG. 12 is a diagram illustrating an example in which replacement is performed with a normal pixel pattern having a small maximum level difference.

FIG. 13 is a flowchart illustrating a pattern replacement processing procedure according to the second embodiment.

FIG. 14 is a diagram illustrating detection of a defective pixel area.

FIG. 15 is a diagram showing normal pixels located at both ends of a defective pixel area A and a defective pixel area B;

FIG. 16 shows an RO in an image processing unit as a storage medium.
FIG. 6 is a diagram showing a memory map of M.

[Explanation of symbols]

 102 Film folder 103 Filter switching device 106 CCD 111 Filter switching drive circuit 116 Image processing unit 119 System controller

Continued on front page F-term (reference) PP23 PP32 PP43 PQ08 PQ12 PQ20 PQ24 SS01 TT09

Claims (16)

[Claims] 1. A defective pixel detecting means for detecting a defective pixel which needs to be corrected by scanning an image; a defective pixel area detecting means for detecting a defective pixel area where the detected defective pixels are continuous; Normal pixel detection means for detecting a normal pixel that does not need correction from around the defective pixel area, normal pixel area detection means for detecting a normal pixel area in which the detected normal pixels are continuous, and the detected normal pixel A replacement unit that replaces the defective pixel area with an area. 2. The image processing apparatus according to claim 1, wherein the defective pixel area detecting means detects the defective pixel area in which the detected defective pixels are continuous in a horizontal direction. 3. The image processing apparatus according to claim 1, wherein the defective pixel area detecting means detects the defective pixel area in which the detected defective pixels are continuous in a vertical direction. 4. The defective pixel area detecting means detects the defective pixel area in which the detected defective pixel is continuous in a horizontal direction and a vertical direction, and according to the number of pixels of the detected defective pixel area. 2. The image processing apparatus according to claim 1, wherein a defective pixel area to be replaced by the replacement unit is determined. 5. The defective pixel area detecting means detects the defective pixel area in which the detected defective pixel is continuous in a horizontal direction and a vertical direction, respectively, and detects a normal pixel located around the detected defective pixel area. 2. The image processing apparatus according to claim 1, wherein a defective pixel area to be replaced by the replacement unit is determined according to a color component of the pixel. 6. The defective pixel area detecting means expands the defective pixel area by treating normal pixels located on both sides of the detected defective pixel area in the sub-scanning direction as a predetermined number of defective pixels. The image processing apparatus according to claim 1, wherein: 7. When the number of pixels constituting a defective pixel area detected by the defective pixel area detecting means is equal to or less than a predetermined number, the replacing means replaces the defective pixel area with the normal pixel area. The image processing apparatus according to claim 1, wherein: 8. When there is a normal pixel around the defective pixel area detected by the defective pixel area detection means, the replacement means replaces the defective pixel area with the normal pixel area. The image processing device according to claim 1. 9. The replacement unit, wherein a difference between a color component of the defective pixel region detected by the defective pixel region detection unit and a color component of a normal pixel located around the defective pixel region is equal to or less than a predetermined value. 2. The image processing apparatus according to claim 1, wherein the defective pixel area is replaced with the normal pixel area in some cases. 10. The normal pixel area detecting means scans a target pixel sequentially from an end of the defective pixel area detected by the defective pixel area detecting means, and detects a color component of the target pixel and a color component of the defective pixel area. 2. The image processing apparatus according to claim 1, wherein a determination is made as to whether or not the target pixel is adopted as a normal pixel in the normal pixel area. 11. The normal pixel area detecting means scans a target pixel sequentially from an end of a defective pixel area detected by the defective pixel area detecting means, and when the target pixel does not reach an end of the image, 2. The image processing apparatus according to claim 1, wherein the pixel of interest is adopted as a normal pixel in the normal pixel area. 12. The normal pixel area detecting means scans the target pixel sequentially from an end of the defective pixel area detected by the defective pixel area detecting means. If the target pixel is not a defective pixel, the normal pixel area detecting means 2. The image processing apparatus according to claim 1, wherein the image processing apparatus is employed as a normal pixel in a normal pixel area. 13. The replacement unit compares the number of pixels of a plurality of normal pixel regions located around the defective pixel region, and determines a normal pixel region used for the replacement based on the comparison result. The image processing apparatus according to claim 1, wherein: 14. The replacement unit compares differences between color components of a plurality of normal pixel regions located around the defective pixel region, and determines a normal pixel region used for the replacement based on the comparison result. The image processing apparatus according to claim 1, wherein the determination is made. 15. A step of scanning an image to detect a defective pixel that needs to be corrected, a step of detecting a defective pixel area where the detected defective pixel is continuous, and a step of detecting a defective pixel area around the detected defective pixel area. An image including a step of detecting a normal pixel that does not require correction, a step of detecting a normal pixel area where the detected normal pixels are continuous, and a step of replacing the defective pixel area with the detected normal pixel area Processing method. 16. A storage medium that is executed by a computer in an image processing apparatus and stores a program for correcting an image, the program comprising: a step of scanning an image to detect a defective pixel that needs to be corrected; Detecting a defective pixel area in which the detected defective pixels are continuous; detecting normal pixels that do not need to be corrected from around the detected defective pixel area; and a normal pixel area in which the detected normal pixels are continuous And a step of replacing the defective pixel area with the detected normal pixel area.