JPH11355511A - Picture processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute correction of a peripheral light quantity (increase in the light quantity) by correcting the reduction component of a peripheral picture with respect to all the pixels based on a distance from the center of a photographic lens and setting the intensity degree of correction based on the density balance of the whole picture obtained by weighting peripheral part picture density more than that of a center part so as to reduce influence to the correcting intensity of the subject of the center part of the picture. SOLUTION: When data are stored in a pre-scanning memory 204, a peripheral light quantity correcting part 220 reads this and weights a pixels based on the distance from the center of the picture and lens characteristics to correct the peripheral light quantity. Based on this weighted picture data, histogram is prepared to obtain shadow density. Based on the difference ΔD between this shadow density and based density, corrected intensity is obtained, the corrected intensity and a light reducing quantity are multiplied to each other to obtain a correcting light quantity being a light quantity which should by corrected. This is added to a photographing light quantity to obtain a corrected photographing light quantity. This corrected photographing light quantity is converted to negative density to output as a picture signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for subjecting image data obtained by photoelectrically reading an image recorded on a recording medium to predetermined image processing to obtain image data for output.

[0002]

2. Description of the Related Art In recent years, a frame image recorded on a photographic film is photoelectrically read by a reading sensor such as a CCD, and image processing such as enlargement / reduction and various corrections is performed on digital image data obtained by the reading. In addition, a technique is known in which an image is formed on a recording material using a laser beam modulated based on digital image data that has been subjected to image processing.

As described above, in the technique of digitally reading a frame image using a reading sensor such as a CCD, the frame image is preliminarily read (so-called pre-scan) and the density of the frame image is read in order to realize accurate image reading. Reading conditions (for example, the amount of light applied to a frame image and CC
D, etc.) and the frame image is read again under the determined reading conditions (so-called fine scan).

Here, in an image photographed by LF (film with lens), the amount of peripheral image light is reduced due to lens aberration and distortion. That is, while the light amount at the center of the image where the main subject can be most positioned is normal, the light amount at the periphery of the wall or the like is small.

In order to solve this problem, the amount of light reduction of a peripheral image is calculated from a histogram of a photographed image or the like, and the amount of the light reduction is added to each pixel or to the entire image to correct (peripheral light amount correction). .

[0006] According to this, the peripheral image becomes bright and the difference from the light amount at the position of the main subject can be reduced.

[0007]

However, in the peripheral light amount correction, the shadow density is calculated from the histogram of the photographed image, and the correction intensity is calculated from the difference between the shadow density and the base density. In the case of an image in which the night sky is photographed in the center, the amount of weight reduction is also added to this night sky, and the correction intensity is set to be small because the night sky is hardly subjected to peripheral light amount correction because it is located in the center.

When the correction is made for each pixel, the correction can be made by omitting the night sky and the like near the center as described above. I can do it.

The present invention has been made in view of the above circumstances, and has as its object to provide an image processing apparatus capable of performing peripheral light amount correction (light amount increase) by reducing the influence of the central portion of an image on the correction intensity of a subject. is there.

[0010]

According to a first aspect of the present invention, a predetermined image processing is performed on image data obtained by reading an image taken from a recording medium on which an image taken through a taking lens is recorded. An image processing apparatus for obtaining image data for output, wherein the image processing apparatus corrects a reduction amount of a peripheral image for all pixels based on information of the photographing lens and a distance from a center of the photographing lens in the recorded image. A peripheral light amount correcting unit and a degree of correction by the peripheral light amount correcting unit are set based on a density balance of the entire image in a state where the density of the peripheral image is weighted more than the density of the central image. Correction intensity setting means.

According to the first aspect of the present invention, when the peripheral light amount correction is performed, the correction reduction amount set by the peripheral light amount correction unit is not executed 100% but is performed at the degree set by the correction intensity setting unit. . That is, the correction intensity setting means sets the intensity of correction by the peripheral light amount correction means based on the density balance of the entire image in a state where the density of the peripheral image is weighted more than the density of the image of the central part. Set.

Thus, the peripheral light amount is appropriately corrected,
In the case where there are many black regions in the central portion as a print image, the black in the central portion suppresses a reduction in peripheral light amount correction.

According to a second aspect of the present invention, a predetermined image processing is performed on image data obtained by reading an image photographed through a photographing lens from a recording medium on which the image has been recorded, and an image for output is obtained. An image processing apparatus that obtains data, based on a lens information acquisition unit that acquires information of the photographing lens, lens information acquired by the lens information acquisition unit, and a distance from a center of the photographing lens in the recorded image. Calculating means for calculating a light amount adjustment amount for calculating the amount of reduction of the peripheral image with respect to all pixels, and correcting means for correcting the image with the light amount adjustment amount calculated by the calculating means. The density of each pixel so that the weight of the pixel at the center position of the image is the smallest and the weight of the pixel at the position farthest from the center is the largest. Weighting processing means for performing weighting processing, histogram creation means for creating a histogram corresponding to the density based on the image data after the weighting processing, and integration values in the histogram created by the histogram creation means from the low density side Shadow density detecting means for detecting a shadow density which is a maximum density value of an area having a predetermined occupancy rate; and a strength of correction of an image performed by the correcting means based on the shadow density detected by the shadow density detection. Correction strength determining means.

According to a second aspect of the present invention, there is provided specific means according to the first aspect of the present invention. First, the weighting processing means determines the density of the pixel at the center position of the image. Each pixel is subjected to a density weighting process so that the weight is the smallest and the weight is the largest for the pixel at the position farthest from the center. Next, a histogram of each pixel corresponding to the density is created by the histogram creating means based on the image data after the weighting process.

A shadow density is detected from the histogram (shadow density detecting means), and a correction intensity is determined based on the shadow density (correction intensity determining means). As a result, an appropriate correction intensity value can be obtained.

According to a third aspect of the present invention, in the second aspect of the present invention, the weighting means is either “0” indicating no weighting or “1” indicating performing weighting. It is represented by binarized data, and is characterized in that the weight on the low density side is 0 and the weight on the high density side is 1 at the boundary of the intermediate density.

According to the third aspect of the present invention, in the weighting processing means, for example, a weight “0” is assigned to the image center side and a weight “1” is assigned to the image peripheral side based on an intermediate value from the image center to the periphery. And According to this, the calculation is facilitated and the image processing speed is emphasized.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the weighting processing means is represented by an analog characteristic curve, and the weighting degree gradually increases as the analog characteristic curve moves toward a higher density side. 3. The image processing apparatus according to claim 2, wherein a proportional curve increases.

According to the fourth aspect of the present invention, the weighting process is performed using an analog characteristic curve in which the degree of weighting gradually increases toward the high density side. Thereby, the weighting becomes accurate, and the image quality is prioritized.

According to a fifth aspect of the present invention, in the invention of any one of the second to fourth aspects, the correction intensity determining means determines that the intensity of the correction is a shadow density in the read image data. The correction strength is determined based on the difference from the base density, and the smaller the difference is, the weaker the correction strength is, and the larger the difference is, the stronger the correction strength is.

According to the fifth aspect of the present invention, the correction intensity determining means determines the intensity of the correction based on the difference between the shadow density and the base density in the read image data. Are set to be weaker and the correction difference becomes stronger as the difference becomes larger.

[0022]

1 and 2 show a schematic configuration of a digital lab system 10 according to the present embodiment.

As shown in FIG. 1, the digital lab system 10 includes a line CCD scanner 14, an image processing section 16, a laser printer section 18, and a processor section 20, and includes a line CCD scanner 14 and an image processing section. The processing unit 16 is integrated as the input unit 26 shown in FIG.
Are integrated as an output unit 28 shown in FIG.

The line CCD scanner 14 is for reading a frame image recorded on a photographic film such as a negative film or a reversal film.
5 size photographic film, 110 size photographic film, and photographic film with a transparent magnetic layer (24
0 size photographic film: so-called APS film), 12
Frame images of photographic film of size 0 and size 220 (Brownie size) can be read. The line CCD scanner 14 reads the frame image to be read by the line CCD 30, A / D converts it in the A / D converter 32, and outputs the image data to the image processor 16.

In this embodiment, a digital lab system 10 in which a photographic film (APS film) 68 of 240 size is applied will be described.

The image processing section 16 stores image data (scanned image data) output from the line CCD scanner 14.
Is input, and image data obtained by photographing with the digital camera 34 or the like, a document (for example, a reflection document, etc.)
Data obtained by reading the image data with a scanner 36 (flat bed type), image data generated by another computer and recorded in a floppy disk drive 38, MO drive or CD drive 40, and received via a modem 42 The communication image data and the like (hereinafter, these are collectively referred to as file image data) can be input from the outside.

The image processing section 16 stores the input image data in the image memory 44, and stores a color gradation processing section 46, a hypertone processing section 48, and a hyper sharpness processing section 50.
Image processing such as various corrections and the like, and outputs the image data to the laser printer unit 18 as recording image data. Further, the image processing unit 16 outputs the image data subjected to the image processing to an external device as an image file (for example, outputs the image data to a storage medium such as an FD, an MO, a CD, or to another information processing device via a communication line). Transmission, etc.).

The laser printer section 18 includes R, G, and B laser light sources 52, and controls a laser driver 54 to record image data (temporarily stored in an image memory 56) input from the image processing section 16. Is applied to the photographic printing paper, and scanning exposure (in the present embodiment, mainly the polygon mirror 58 and the fθ lens 60) is performed.
An image is recorded on the photographic paper 62 by an optical system using the same. Further, the processor unit 20 includes a laser printer unit 18.
The photographic paper 62 on which an image has been recorded by scanning exposure is subjected to color development, bleach-fixing, washing, and drying.
Thus, an image is formed on the printing paper.

(Configuration of Line CCD Scanner) Next, the configuration of the line CCD scanner 14 will be described. FIG. 1 shows a schematic configuration of an optical system of the line CCD scanner 14. This optical system includes a light source 66 for irradiating a photographic film 68 with light.
A light diffusing plate 72 for diffusing light irradiated on the photographic film 68 is provided.

The photographic film 68 is formed by a film carrier 74 disposed on the side where the light diffusion plate 72 is disposed.
The frame image is conveyed so that the screen is perpendicular to the optical axis.

On the opposite side of the photographic film 68 from the light source 66, a lens unit 76 for imaging light transmitted through the frame image and the line CCD 30 are arranged in order along the optical axis. Although only a single lens is shown as the lens unit 76, the lens unit 76 is actually a zoom lens including a plurality of lenses. Note that a selfoc lens may be used as the lens unit 76. In this case, it is preferable that both end surfaces of the SELFOC lens be as close to the photographic film 68 and the line CCD 30 as possible.

The line CCDs 30 are arranged in a line along the width direction of the photographic film 68 conveyed by a plurality of CCD cells, and three sensing lines provided with an electronic shutter mechanism are provided in parallel with each other at intervals. Each of the R, G, and B color separation filters is mounted on the light incident side of each sensing unit (a so-called three-line color CCD). The line CCD 30 is arranged so that the light receiving surface of each sensing unit coincides with the imaging point position of the lens unit 76.

Although not shown, the line CCD 3
A shutter is provided between the lens unit 0 and the lens unit 76. (Configuration of Control System of Image Processing Unit 16) FIG. 3 shows the main components of the image processing unit 16 shown in FIG. 1, including an image memory 44, a color gradation process 46, a hypertone process 48, and a hyper sharpness process 50. A detailed control block diagram for performing the processing is shown.

Each of the RGB digital signals output from the line CCD scanner 14 is subjected to predetermined data processing such as darkness correction, defective pixel correction, and shading correction in a data processing unit 200, and then a Log converter 202. Is converted into digital image data (density data), the pre-scan data is stored in the pre-scan memory 204, and the main scan data is stored in the main scan memory 20.
6 is stored.

The pre-scan data stored in the pre-scan memory 204 is sent to a pre-scan processing unit 2 comprising an image data processing unit 208 and an image data conversion unit 210.
12 is sent. On the other hand, the main scan memory 206
Is transmitted to a main scan processing unit 218 including an image data processing unit 214 and an image data conversion unit 216.

The pre-scan processing section 212 and the main scan processing section 218 execute correction based on the lens characteristics when an image is photographed and the strobe light distribution characteristics when photographing using a strobe.

In the image data processing units 208 and 216, color balance adjustment, contrast adjustment (color gradation processing),
Brightness correction, saturation correction (hypertone processing), hypersharpness processing, etc.
X) It is executed by a known method such as an operation.

The image data processing units 208 and 216 are provided with peripheral light amount correction units 220 and 222 for correcting the light amount at the periphery (background) of the image before the above-described adjustment, correction, and the like.

That is, the peripheral light amount correction units 220, 2
At 22, the main subject (person, etc.) is determined based on the lens characteristics.
, The peripheral (background) light amount drop is corrected. The light amount correction in the peripheral light amount correction units 220 and 222 will be described later.

Image data converter 210 on prescan side
In, the image data processed by the image data processing unit 208 is converted into display image data to be displayed on the monitor 16M based on the 3D-LUT. On the other hand, in the image data conversion unit 216 on the main scan side,
The image data processed by the image data processing unit 214 is converted into print image data in the laser printer unit 18 based on the 3D-LUT. Although the display image data and the print image data have different color systems, they are matched by various corrections as described below.

That is, a condition setting unit 224 is connected to the prescan processing unit 212 and the main scan processing unit 218.

The condition setting section 224 includes the setup section 22
6, a key correction unit 228, and a parameter integration unit 230.

The setup unit 226 uses the pre-scan data to set the main scan reading conditions, supplies the main scan reading conditions to the line CCD scanner 14, and sets the image processing conditions of the play scan processing unit 212 and the main scan processing unit 218. The calculated values are supplied to the parameter integration unit 230.

The key correction unit 228 is used to adjust image processing conditions in accordance with keys for adjusting the density, color, contrast, sharpness, saturation, etc., set on the keyboard 16K, and various instructions input with a mouse. Is calculated and supplied to the parameter integration unit 230.

The parameter integration unit 230 sends the image processing conditions received from the setup unit 226 and the key correction unit 228 to the image data processing units 208 and 214 on the prescan side and the main scan side, and corrects or regenerates the image processing conditions. Set.

The condition setting section 224 is connected to a film characteristic storage section 232, which stores various film characteristics.

The characteristics of the film are the gradation characteristics (γ characteristics)
In general, it is represented by a curve whose density changes three-dimensionally according to the exposure amount. Since this point is a well-known technique, detailed description will be omitted.

In the present embodiment, the film type is specified by recording information indicating the film type on the magnetic recording layer of the APS film. It can be read by the head. In the case of a 135-size film, the determination may be made based on its shape (perforations are provided at relatively short pitches at both ends in the width direction) or the like, or an operator may make a key input.

The condition setting section 224 is connected to a lens characteristic data supply section 234. The lens characteristic data supply unit 234 obtains information for identifying the camera that has photographed the film, and obtains the lens characteristic corresponding to the photographing camera corresponding to the obtained identification information by the peripheral light amount correction units 220 and 22.
2.

That is, the lens characteristic data supply unit 234
Has a memory (table). This memory includes lenses (for example, lenses applied to LF, strobes and interchangeable lenses mounted on general cameras) corresponding to various camera types. In this embodiment, the LF lens is mainly used as the correction target.) Is stored.

In the lens characteristic data supply unit 234, the acquired lens characteristic data (for example, LF
This is a lens characteristic. As the distance from the center of the image increases,
gE is increasing (negative trend). ), The light distribution characteristics are read out and supplied to the peripheral light amount correction units 220 and 222. The shooting distance is APS
If it is a film, it may be recorded on the magnetic recording layer.
If the film is a 135 size film or the like, it may be optically recorded or a separate recording medium may be used.

Here, in the peripheral light amount correction, depending on the photographing situation, the peripheral light amount correction may be rather unpleasant and the finished print may feel uncomfortable.

FIGS. 6A and 6B show light distribution characteristics when photographing is performed using the LF 100 in the situation shown in FIG. That is, FIG. 5 shows a state in which two main subjects (persons) 104 stand with the center of the image therebetween (the center of the image is the background), and the background at the center of the image is visible from the window. In the case of the night sky, in such a situation, even if the peripheral light amount correction is performed, the degree of the peripheral light amount correction is small or not performed at all even though the background at the center of the image remains black and there is almost no adverse effect. (See FIG. 6A). Further, as an extreme example, if the peripheral light amount correction is performed ignoring the image in the central portion, as shown in FIG. 6B, an excessive intensity correction may be performed such that the central portion of the image becomes thin. .

For this reason, in the present embodiment, an optimum print is obtained by setting the intensity of the peripheral light amount correction and changing the intensity of the peripheral light amount correction as necessary (according to the state of the image). I have to. The intensity of the peripheral light amount correction can take a level from 0 to 1, with level 0 indicating no correction and level 1 indicating maximum correction (see FIG. 10).

The intensity of the peripheral light quantity correction is set based on the shadow density value of the read image. Actually, as shown in FIG. 10, the difference is set based on a correction intensity characteristic curve having the difference between the shadow density and the base density (shadow density-base density) on the horizontal axis.

Although the shadow density is obtained from the histogram of the read image, if the histogram of the actual image is used as it is, the shadow density is low, so that an appropriate intensity cannot be obtained. That is, the shadow density is reduced by the background of the night sky at the center of the image, and as a result, the difference between the shadow density and the base density is reduced, and the correction strength is reduced.

Therefore, a histogram is formed from the image data after the predetermined weighting according to the distance from the center of the image. As shown by the solid line in FIG. 8, the weight is not weighted on the center side (0) at the middle point (for example, 10 mm in FIG. 8) located farthest from the center of the image, and weighted on the peripheral side (1). ) (Binarization characteristic). As a result, the histogram shifts to the right (high density side) as shown in FIG. 9, and the shadow density can be increased. Note that the weighting may be a tendency to increase the weighting from the center of the image to the periphery. For example, the weighting may be an analog characteristic curve as shown by a chain line in FIG.

The operation of the present embodiment will be described below.

The operator inserts the photographic film 68 into the film carrier 74 and operates the keyboard 1 of the image processing section 16.
When a frame image reading start is instructed by 6K, the photographic film 22 is started to be conveyed in the film carrier 74. By this transport, a pre-scan is performed. That is,
While transporting the photographic film 68 at a relatively high speed, the line CCD scanner 14 reads not only image frames but also various data outside the image recording area of the photographic film 68. The read image is displayed on the monitor 16M.

At this time, the size of the frame image is recognized, and, for example, in the case of a panoramic size frame image, the plain portions unique to the panoramic size image (both ends in the width direction of the photographic film) are shielded.

Next, the reading conditions at the time of fine scan are set for each frame image based on the prescan result of each frame image, and the reading conditions at the time of fine scan are set based on the prescan result. It is set every time.

When the setting of the reading conditions at the time of the fine scan for all the frame images is completed, the photographic film 68 is set.
Is conveyed in the direction opposite to the prescan, and a fine scan of each frame image is executed.

At this time, since the photographic film 68 is being conveyed in the direction opposite to that in the pre-scan, the fine scan is sequentially performed from the last frame to the first frame.
In the fine scan, the transport speed is set slower than in the pre-scan, and the reading resolution is accordingly increased. In addition, at the time of pre-scanning, the image state (for example, captured image aspect ratio, under, normal, over,
Since the shooting state such as super-over and the presence / absence of flash shooting are recognized, it is possible to read under appropriate reading conditions.

In the above, the pre-scan memory 204
When the pre-scan data is stored in the pre-scan data processing unit 212, the peripheral light amount correction unit 220 of the pre-scan data processing unit 212 reads out the pre-scan data and performs peripheral light amount correction. Hereinafter, the peripheral light amount correction procedure will be described with reference to the flowchart of FIG.

In step 150, the peripheral light amount correction unit 22
At 0, the pre-scan data is read from the pre-scan memory 204, and then the density D1 is calculated (step 152) with reference to Table 1 for each of RGB (step 151).

Next, in step 154, the photographing light quantity logE1 is calculated using the film characteristics read from the film characteristic storage unit 232 with reference to Table 2 (step 155).

In the next step 156, the lens characteristics obtained from the lens characteristic data supply unit 234 (for example, FIG.
Ref.) Is calculated, and the process proceeds to step 157. In step 157, the pixels are weighted based on the distance from the center of the image and the lens characteristics. As shown by the solid line in FIG. 8, the intermediate value of the distance (10 mm) is determined, and pixels having a distance shorter than the intermediate value are not weighted (weight 0). A weight is assigned to the pixel (weight 1).

The weighting may be determined according to the distance from the center of the image based on a characteristic curve that changes in an analog manner, as shown by the chain line in FIG.

In the next step 158, a histogram (see FIG. 9) is created based on the weighted image data. As shown in FIG. 9, the weighted image data can be shifted as a whole to a higher density side than the unweighted image data.

In step 159, the shadow density is obtained from the histogram. This shadow density is a density value indicating about 3% of the entire area of the histogram, and is shown in FIG.
As shown in (1), by performing weighting, the difference between the shadow density and the base density can be increased.

In the next step 160, step 159
(Correction intensity) is obtained based on the shadow density obtained in (1) (actually, based on the difference ΔD between the shadow density and the base density). The correction intensity is increased as the difference ΔD increases (saturation (correction intensity level 1) occurs at a predetermined density difference ΔD). In step 162, the correction intensity is multiplied by the reduced light amount ΔlogE to calculate a corrected light amount ΔV which is a light amount to be corrected. Then, Step 1
At 64, this is added to the photographing light quantity logE1 to obtain a corrected photographing light quantity logE2.

Next, in step 166, the corrected light amount
The logE2 is again converted into the negative density D2, and step 168 is performed.
Output as an image signal.

The density correction procedure according to the lens characteristics in the peripheral light quantity correction unit 220 has been described above.
In the setup unit 226 of the peripheral light amount correction unit 2
Receiving the corrected data from 20, it creates a density histogram, calculates image features such as highlights and shadows, sets the main scan reading conditions, and supplies it to the line CCD scanner 14.

The image subjected to the peripheral light amount correction is thereafter processed by the LUT and MTX, and then subjected to necessary image processing such as sharpness processing and dodging processing, and converted by the image data conversion unit 210. Are displayed on the monitor 16M.

The setup section 226 sets various image processing conditions such as gradation adjustment and gray balance adjustment, and supplies the same to the parameter integration section 230.

The parameter integration unit 230 that has received the image processing conditions supplies them to the pre-scan processing unit 212 and the main scan processing unit 218.

The main scan is performed in substantially the same manner as the pre-scan, and the output signal from the line CCD 30 is A /
The digital signal is converted into a digital signal by the D converter 32, processed by the data processing unit 200 of the image processing unit 16, converted into main scan data by the Log converter 202,
Sent to 6.

When the main scan data is sent to the main scan memory 206, it is read out by the main scan processing unit 218, and the main scan processing unit 218 performs the same image processing as the processing in the pre-scan processing unit 212. The image data is converted into image data of a color system suitable for the laser printer unit 18 by the image data conversion unit 216 and output.

As described above, in the related art, in particular, the coefficient for performing the peripheral light amount correction according to the lens characteristics is uniformly calculated from the entire screen. , A scene with a white wall around it "
The correction coefficient was getting smaller. That is, though the peripheral dimming hardly occurs at the center of the image, the correction coefficient is small because the subject at the center is close to the base density.

Therefore, when the histogram of the entire image is created, the weighting is increased (ie, the intensity is biased toward the periphery) as the distance from the center of the image is increased, and the correction intensity is calculated.
The image quality is improved, and an appropriate photographic image can be obtained even with an inexpensive and simple camera such as LF.

The present invention is not limited to the LF100 but can be applied to all camera lenses. However, a remarkable effect can be obtained in a camera equipped with an inexpensive lens such as the LF100.

The present invention can be applied not only to a camera using a photographic film but also to an image taken by a camera that records an image on another recording medium such as a digital camera.

[0083]

As described above, the image processing apparatus according to the present invention has an excellent effect that the density of the black portion as a print image can be reduced as much as possible and the peripheral light amount can be corrected (increased light amount). Have.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a digital laboratory system according to an embodiment of the present invention.

FIG. 2 is an external view of a digital laboratory system.

FIG. 3 is a control block diagram of an image processing unit.

FIG. 4 is a flowchart showing a peripheral light amount correction procedure based on strobe light distribution characteristics.

FIG. 5 is a perspective view showing a situation in which shooting is performed using a strobe with an LF.

FIG. 6 is a print pattern diagram when the image is captured in FIG. 6;

FIG. 7 is a lens characteristic diagram of LF (film with lens).

FIG. 8 is a weighting characteristic diagram for weighting each pixel before creating a histogram of a captured image.

FIG. 9 is a histogram of a captured image.

FIG. 10 is a characteristic diagram for determining a correction strength.

[Explanation of symbols]

 Reference Signs List 10 digital laboratory system 14 line CCD scanner 16 image processing unit 66 light source unit 68 photographic film 200 data processing unit 202 log converter 204 prescan memory 206 main scan memory 208 image data processing unit 212 prescan processing unit 214 image data processing unit 218 Main scan processing unit 220, 222 Peripheral light amount correction unit 224 Condition setting unit 234 Lens characteristic data supply unit

Claims (5)

[Claims] An image processing apparatus for performing predetermined image processing on image data obtained by reading an image taken from a recording medium on which the image has been taken through a taking lens and obtaining image data for output. A peripheral light amount correction unit configured to correct a reduction amount of a peripheral image for all pixels based on information of the photographing lens and a distance from a center of the photographing lens in the recorded image; An image processing apparatus comprising: a correction intensity setting unit configured to set a degree of correction by the peripheral light amount correction unit based on a density balance of the entire image in a state in which the density of the image at the center is weighted more than the density of the image. 2. An image processing apparatus that obtains output image data by performing predetermined image processing on image data obtained by reading an image taken from a recording medium on which an image taken through a photographing lens is recorded. A lens information acquiring unit for acquiring information on the photographing lens; a lens information acquired by the lens information acquiring unit; and a periphery of all pixels based on a distance from a center of the photographing lens in the recorded image. Calculating means for calculating a light amount adjustment amount for calculating the amount of reduction of the image, and adjusting the light amount; correcting means for correcting the image based on the light amount adjustment amount calculated by the calculating means; The minimum weight for the pixel density,
And weighting processing means for performing a density weighting process on each pixel so that the weight of the pixel at a position farthest from the center becomes the maximum, based on the image data after the weighting process, Histogram creating means for creating a corresponding histogram, and shadow density detecting means for detecting a shadow density which is a maximum density value of a region where an integrated value in the histogram created by the histogram creating means has a predetermined occupancy from a low density side. An image processing apparatus comprising: a correction intensity determining unit that determines an intensity of image correction performed by the correction unit based on the shadow density detected by the shadow density detection. 3. The weighting processing means outputs “0” indicating no weighting and “1” indicating performing weighting.
3. The image processing apparatus according to claim 2, wherein the weighting on the low density side is 0 and the weighting on the high density side is 1 at the boundary of the intermediate density. 4. The method according to claim 2, wherein the weighting processing means is represented by an analog characteristic curve, and the analog characteristic curve is a proportional curve in which the degree of weighting gradually increases toward the high density side. The image processing apparatus according to any one of the preceding claims. 5. The correction strength determining means determines the strength of the correction based on a difference between a shadow density and a base density in the read image data, wherein the smaller the difference is, the weaker the correction strength is; The image processing apparatus according to claim 2, wherein the correction intensity is high.