JP3545484B2 - Density adjustment method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a density adjustment method, and more particularly, to a density adjustment method when an image is obtained by surface exposure.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a television monitor or the like to which a liquid crystal display device is applied. The liquid crystal display device is assembled with a liquid crystal panel as a main component. This liquid crystal panel is applied to a printer that displays a digital image and projects the transmitted image on a photosensitive material to print it.
[0003]
As such a printer, an index print in which frames are reduced and arranged in a matrix so as to be easily searched for what kind of photograph is taken on one developed film is known (for example, an index print is known). JP-A-61-122639).
[0004]
In addition, the present applicant continuously processes the printing exposure of the index print as described above and the printing exposure of each image frame, thereby making it possible to create the index print without deteriorating the high-speed processing performance of the photographic print. (For example, JP-A-6-190586).
[0005]
The photographic printer includes, for example, a photosensitive material transporting section for providing an index print area between print images of one film, and an index print section for printing and exposing an index print image (index image) in the index print area. And a liquid crystal panel is used as a burn-in display means in the index print section.
[0006]
In these apparatuses including the above-described printer, when the liquid crystal panel is subjected to surface irradiation and exposure, unevenness in density, particularly light source unevenness due to light from a light source, may occur. FIG. 2A is a view showing this, in which the left side shows an ideal print when no density unevenness occurs, and the right side shows an actually obtained print. In these devices, an optical device such as a diffusion plate is incorporated to prevent optical source unevenness.
[0007]
[Problems to be solved by the invention]
However, when an optical device is incorporated, the number of components increases, and the device itself becomes larger. Further, after the optical device is incorporated in the manufacturing process or when the optical system device is replaced, an optical adjustment operation such as a focal length is required.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described circumstances, and has as its object to provide a density adjustment method capable of easily and automatically adjusting density unevenness occurring in an image printing process.
[0009]
[Means for Solving the Problems]
The density adjusting method according to claim 1, further comprising a liquid crystal panel in which a plurality of pixels are arranged vertically and horizontally and each pixel can be controlled to a predetermined gradation, and wherein each pixel of the liquid crystal panel is disposed in a predetermined position on a printing optical path. On the other hand, when displaying an image in accordance with the gradation set on the basis of the total transmission or total non-transmission state, a uniform gradation image is displayed on the liquid crystal panel, and a print image of the image is displayed. obtained, it was selected pixels corresponding to the minimum or maximum concentration by measuring the concentration of the resulting printed image, for each pixel, by calculating the density difference between the screened pixel, each based on the concentration difference Adjust the gradation so that the pixels have a uniform density, and while maintaining the relative difference of the adjusted gradation, shift any one of the pixels until the pixel is first in a fully transmitting or totally non-transmitting state. Registering the gradation of the position as the reference of each pixel, It is a symptom.
[0010]
[Action]
According to the density adjusting method of the present invention, for example, on the basis of the total opacity, each pixel of the liquid crystal panel is set to a uniform gradation to obtain a print image. The density of the printed image is measured, the pixel corresponding to the maximum density is selected, the density difference between the selected pixel and each pixel is calculated, and based on this, each pixel has a uniform density. Adjust the gradation. Next, the shift is performed in the totally opaque direction while maintaining the relative difference of the adjusted gradation, and the shift is stopped when any of the pixels (the selected pixels) becomes completely opaque. . The gradation at this shift position is registered as a reference for each pixel. As a result, unevenness of light source and unevenness of density due to deterioration of the liquid crystal panel during manufacture or over time can be eliminated, and a density according to the set gradation can be obtained. Can be produced.
[0011]
Further, it is possible to omit the incorporation of the optical system device for correcting the density unevenness and the adjustment work of the optical system device resulting from the incorporation. Further, the density can be adjusted by an easy and simple process, so that the density adjusting operation can be automated.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows laboratory equipment used in the concentration adjusting method of the present invention. These laboratory devices are composed of a printer 12 for printing and exposing a predetermined image on photographic paper 38, and a developing device 14 for developing the photographic paper 38 printed and exposed by the printer 12 to visualize it. .
[0013]
The printer 12 is provided with a light source 18 for printing exposure using a halogen lamp and a reflector. Instead of the halogen lamp, a compact LED may be used. A color separation filter 20 for each of R (red), G (green), and B (blue) is disposed on the printing optical axis L of the light source emitted from the light source 18. Each of these color separation filters 20 is configured to protrude and retract on the printing optical axis L according to a signal from the driver 22.
[0014]
A liquid crystal panel 24 is provided on the printing optical axis L below the color separation filter 20. A liquid crystal panel driver 26 for driving the liquid crystal panel 24 is connected to the liquid crystal panel 24, and the liquid crystal panel driver 22 is further connected to a controller 28 for controlling the driving of the liquid crystal panel driver 26.
[0015]
A negative image storage unit 30 is connected to the controller 28. The controller 28 controls the driving of the pixels constituting the liquid crystal panel 24 based on the negative image data input from the negative image storage unit 30.
[0016]
A black shutter 34 is arranged on the printing optical axis L below the liquid crystal panel 24 in FIG. 1 with the printing lens 32 interposed therebetween. The black shutter 34 opens and closes in response to a drive signal from a driver 36, and passes or blocks light on the printing optical axis L. In addition, the lens 32 is movable along the printing optical axis L, so that the magnification can be changed.
[0017]
Below the black shutter 34 in FIG. 1, photographic paper 38 is wound in a layer around a rotating shaft (not shown) on the left side of FIG. 1, and is pulled out from the top of the layer. The drawn-out photographic paper 38 is sandwiched between photographic paper transport rollers 40, transported along the arrow W by driving the photographic paper transport rollers 40, and positioned at a predetermined position by stopping the transport.
[0018]
The developing device 14 is provided for developing the printing paper 38 that has been printed and exposed by the printer 12. The developing device 14 is provided with a color developing tank 42, a bleach-fix tank 44, a rinsing tank 46, and a drying unit 48 from the left side in FIG.
[0019]
The printing paper 38 on which the image has been printed is conveyed to the color developing tank 42. The color developing tank 42 performs a developing process by immersing the printing paper 38 in a developing solution.
[0020]
The developed photographic paper 38 is conveyed to a bleach-fixing tank 44 adjacent to the color developing tank 42. The bleach-fixing tank 44 performs a fixing process by immersing the printing paper 38 in a fixing solution.
[0021]
The photographic paper 38 on which the fixing process has been performed is conveyed to a plurality of rinsing tanks in which the photographic paper 38 is immersed in washing water and subjected to a washing process.
[0022]
The photographic paper 38 that has been subjected to the water-washing process is conveyed to a drying unit 48 adjacent to the rinsing tank 46. The drying unit 48 performs a drying process by blowing hot air on the printing paper 38.
[0023]
Here, when displaying an image on the liquid crystal panel 24, light may leak even if each pixel is fully closed. This can occur due to mechanical degradation over time or over time. It may also occur due to a difference in the intensity of light from the light source 18. Therefore, in this embodiment, the density measuring device 16 is provided as one of the means (test mode) for adjusting the density unevenness on the liquid crystal panel 24.
[0024]
The density measuring device 16 is provided for measuring the density on the photographic paper 38 that has been subjected to the development processing. The concentration measurement functions when the test mode is set by the controller 28.
[0025]
The density measuring device 16 includes a support table 50 for supporting the photographic paper 38 which has been subjected to the development processing, and a CCD sensor 52. The photographic paper 38 conveyed to the density measuring device 16 is arranged on a support table 50, and the density of the print is measured by the CCD sensor 52.
[0026]
The CCD sensor 52 is connected to the controller 28, and transmits the measured print density to the controller 28.
[0027]
A mode setting unit 54 is connected to the controller 28. The mode setting unit 54 can be switched between a test mode and a normal mode for displaying a normal image and performing printing exposure, so that either one can be selected. The test mode uses a gray image composed of uniform halftones.
[0028]
With the above configuration, when the test mode is selected by the mode setting unit 54, an image with a uniform gradation is displayed on the liquid crystal panel 24 via the liquid crystal panel driver 26. The image of the uniform gradation displayed on the liquid crystal panel 24 is printed and exposed, subjected to development processing, measured for density, and the data is sent to the controller 28.
[0029]
The density adjustment processing will be described below with reference to FIG. 2 (B) to 2 (C), the left column shows a print which is expected to be obtained by printing an image displayed on the liquid crystal panel 24 when no density difference occurs. The right column shows the actual prints obtained. For convenience, a print in the left column is called an expected print, and an image in the right column is called an actual print.
[0030]
When the gray image in the test mode is displayed on the liquid crystal panel 24, if the unevenness due to the light source and the unevenness in the density due to other factors do not occur, the difference in the density is expected as shown in the expected print shown in FIG. (Ideal print) does not occur, but a density difference (light source unevenness) occurs due to irradiation of the light source 18 and the like as in the actual print shown on the right side of FIG.
[0031]
Since the image applied to the test mode is a uniform image (gray image) having a halftone, the pixel floor on the liquid crystal panel 24 corresponding to the portion where the light source unevenness has occurred and the portion where the light source unevenness has not occurred. The keys are equal. Here, the pixels corresponding to the printing of the image having the uniform gradation are specified, and the pixels corresponding to the portions having the maximum density are selected. The density difference between a selected pixel and a non-selected pixel is calculated for all pixels. The gradation is adjusted for each pixel according to the obtained density difference. The adjustment is performed by changing the voltage for each pixel.
[0032]
As a result, a relative difference occurs in the adjusted gradation. While maintaining this relative difference, the shift is performed until the selected pixel is completely opaque. The gradation at this shift position is registered as a reference for each pixel.
[0033]
The left part of FIG. 2C shows an expected print of an image having a uniform intermediate gradation formed as a result of adjusting the gradation. In the actual print in this case, there is no density difference as shown on the right side of FIG.
[0034]
The pixel can be easily specified by matching the resolution of the CCD sensor 52 with the resolution of the liquid crystal panel 24, but may be specified by another method.
[0035]
FIG. 3A is an actual print of an image of uniform gradation shown on the right of FIG. 3B shows the density between IIIB and IIIB in FIG. 3A, and the right side of FIG. 3B shows the gradation of the liquid crystal panel 24 at this time. The gradation 1.0 indicates the density when the light from the light source 18 is completely transmitted, and the gradation 0 indicates the density when the light from the light source 18 is not transmitted at all. A portion having a low density is a density at an intermediate gradation of an image in the test mode, and a portion having a high density is a portion having uneven density. In the print of FIG. 3A, it is assumed that the densities of the portions where the density unevenness occurs are all equal.
[0036]
Pixels having a high density are selected and gradation adjustment is performed. FIG. 3C shows a print in which the gradation has been adjusted. In this case, the density of the pixel (between IIIB and IIIB) is shown on the left side of FIG. 3D, and the gradation on the liquid crystal panel 24 is shown on the right side of FIG.
[0037]
When the shift is performed as described above while maintaining the relative difference of the adjusted gradation as shown in FIG. 3D, a reference value as shown in FIG. 3E can be obtained.
[0038]
Next, the operation of the present embodiment will be described with reference to FIG.
The mode setting unit 54 is switched to select the test mode, and the density adjustment processing described below is performed.
[0039]
In step 100, the flag F is reset (0), and in step 102, a display image is selected. Since the display image is in the test mode, an image of a uniform gray level of gray is selected.
[0040]
When the selection of the display image is completed, the selected image is displayed on the liquid crystal panel 24 in step 104. At this time, the gradation of each pixel constituting the liquid crystal panel 24 is the same gradation.
[0041]
When the image is displayed, the image is printed on the photographic paper 38 by the light source 18 in step 106 and developed by the developing device 14 in step 108. If density unevenness occurs here, a density difference occurs on the developed print.
[0042]
When the development process is completed, it is determined in step 110 whether the flag F is set (1). Since the flag F is set when the automatic adjustment is completed once, it is naturally reset at the first stage. Accordingly, an affirmative determination is made in step 110, and the process proceeds to step 112, where the density is measured by the CCD sensor 52 in the density measuring device 16.
[0043]
When the density is measured, in step 114, the density measured by the CCD sensor 52 is compared between the pixels, the pixel corresponding to the maximum density in the print is selected, and the maximum density value is determined for all the pixels. Is calculated, and the gradation is adjusted.
[0044]
When the calculation is completed and the gradation is adjusted for each pixel, in step 116, a reference gradation for each pixel is set (shift adjustment).
[0045]
When the setting of the gradation is completed, it is determined in step 118 whether or not a print is produced and the result of the density adjustment is confirmed (print confirmation). If the print is not confirmed, the determination is negative, the processing in the test mode is terminated, and the mode setting unit 54 is switched to select print production of a normal image, and the image stored in the negative image storage unit 30 is selected. To obtain a print of an image whose density has been adjusted.
[0046]
On the other hand, when confirming the print, in step 120, the flag F is set, and the process returns to step 104, where a gray image is displayed on the liquid crystal panel 24 with the gradation corrected.
[0047]
When the image is displayed, in steps 106 and 108, printing exposure and development processing are performed. In step 110, this determination is denied (passing step 120), and the routine proceeds to step 122.
[0048]
After the development is completed, the operator visually checks the image and determines whether or not adjustment is necessary again. As a result of the determination, if retry is necessary, retry is instructed by a predetermined key operation. In step 122, when there is this instruction, the process proceeds to step 124.
[0049]
At step 124, it is determined whether to retry the test mode. That is, as a result of confirming the print after the density adjustment in step 122, if there is a key operation that does not require the density adjustment in the test mode again, the determination is negative and the density adjustment processing ends. If there is another key operation for which density adjustment is desired, the determination is affirmative, the process returns to step 100, and the test mode is retried.
[0050]
By a series of these processes, an image is displayed on the liquid crystal panel 24 composed of the adjusted gradation pixels, and the image is printed, exposed and developed to obtain a print without density unevenness. In addition, these processes are simple and can be automated.
[0051]
FIG. 5 shows a case where a negative image stored in the negative image storage unit 30 is printed and exposed after a series of density adjustment processing in the test mode is completed.
[0052]
In FIG. 5, the upper left part shows an expected print obtained as a result of adjusting the gradation of the pixel, setting the gradation from the registered density value, and completing all processes, and the lower part shows the print. And the expected print of the negative image stored in the negative image storage unit 30. The expected print obtained by superimposing these two images is shown in the center of FIG. On the right in FIG. 5, actual prints obtained from these images are shown. As described above, this print is subjected to a series of processes to remove density unevenness.
[0053]
In this embodiment, the test mode is a gray uniform image. However, the image is not particularly limited as long as the image sets a uniform gradation on the liquid crystal panel 24.
[0054]
Further, in the present embodiment, the pixel is adjusted based on the location of the maximum density for the location where the density unevenness has occurred, but the density of the reference location and the tone adjustment of the pixel corresponding thereto are adjusted in this embodiment. If applied based on the example, it is also possible to adjust the gradation based on the minimum density part instead of the maximum density part. This can be appropriately selected depending on the range in which the density unevenness has occurred, the gradation of the image having the uniform gradation in the test mode to be used, and other conveniences.
[0055]
In the present embodiment, the processing for removing the density unevenness based on the light source unevenness by the light source 18 has been described. However, the processing is not limited to the light source unevenness. It can also be applied to removal.
[0056]
For example, a case where dirt adheres to one of the color separation filters 20 and density unevenness caused by the dirt is included. In this case, the density unevenness is measured at the time of printing exposure using a filter to which dirt has adhered, the density is adjusted according to the method described above, and a negative image is displayed on the liquid crystal panel 24. Can be removed. If it is desired that the gradation for each color component is the same, even if the density unevenness is caused by one filter, the gradation after the density adjustment during printing exposure using each filter. May be applied.
[0057]
In this embodiment, the CCD sensor 38 is used as the transmission density measuring means. However, the present invention is not limited to this as long as the density on the photographic paper 38 obtained by printing and exposing the test mode image can be measured.
[0058]
Further, the present invention can be applied to an index printer capable of printing both a normal size image and an index image. In this case, when quick processing is often desired, the adjustment time can be shortened by automating the adjustment work. Further, since the number of components is not increased, the size of the device structure is not increased. In the index print, since each image is reduced, the influence of density unevenness is large. However, such an effect can be reduced by applying the present invention.
[0059]
【The invention's effect】
As described above, according to the present invention, it is possible to easily and automatically adjust density unevenness occurring in an image printing process.
[Brief description of the drawings]
FIG. 1 is a schematic view of a laboratory apparatus according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram illustrating a density adjustment method according to an embodiment of the present invention.
FIG. 3 is a conceptual diagram illustrating a density adjustment method according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating a density adjustment method according to an embodiment of the present invention.
FIG. 5 is a conceptual diagram illustrating a density adjustment method according to an embodiment of the present invention.
[Explanation of symbols]
12 Printer 14 Developing device 16 Density measuring device 18 Light source 20 Color separation filter 24 Liquid crystal panel 28 Controller 38 Printing paper 52 CCD sensor 54 Mode setting section

Claims (1)

A plurality of pixels are arranged vertically and horizontally and each pixel is provided with a liquid crystal panel that can be controlled to a predetermined gradation. When displaying an image according to the gradation set based on the transmission state,
Displaying an image of uniform gradation on the liquid crystal panel,
Obtain a print image of the image,
Measure the density of the obtained print image and select the pixel corresponding to the minimum or maximum density,
For each pixel, calculate the density difference from the selected pixel, and adjust the gradation so that each pixel has a uniform density based on the density difference,
While maintaining the relative difference of the gradation after adjustment, that one of the pixels is shifted until the full transmission or total opaque state to the earliest, and registers the tone of the shift position as the reference for each pixel ,
A density adjustment method characterized by the following.

Images