JP2004333194A - Method for measuring intensity in display monitor, and display qc method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow even a user who is not equipped with a telescopic luminance meter to obtain nearly the same precision as that obtained when using the telescopic luminance meter, and to check variations in the display performance of a display. <P>SOLUTION: A method for measuring intensity in displays obtains the corresponding relationship between intensity measured by the telescopic luminance meter and illuminance measured by an illuminometer on the surface of the displays, and converts illuminance measured by the illuminometer to intensity measured by the telescopic luminance meter in an actual measurement. A display QC method and its program use the intensity measurement method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display monitor luminance measurement method and a display QC method using the same, and more specifically, without using an expensive telephotometer at the display monitor usage site. The present invention relates to an improved method for checking fluctuations in display performance and the like, and a display QC method using the same.
[0002]
[Prior art]
Diagnostic images taken with medical diagnostic / measurement devices such as X-ray diagnostic devices, MRI (magnetic resonance imaging) diagnostic devices, and various CT (computer tomography) devices are usually X-ray films and other film photosensitive materials. Are recorded on a light transmissive image recording film and reproduced as a light transmissive image. Conventionally, the diagnosis is performed by setting the film on which the diagnostic image is reproduced in an observation apparatus called a schacus ten and observing the film while irradiating light from the back.
[0003]
On the other hand, in recent years, diagnostic images taken by the above-described medical diagnosis / measurement apparatus can be displayed on various displays and monitors (hereinafter also simply referred to as “displays”) for observation / diagnosis (electronic Schaukasten). It is getting done. The problem with this electronic Schaukasten is that the display performance fluctuates mainly over time (usually deterioration).
[0004]
For this problem, for example, JISZ4752-2-5 (Evaluation of quality maintenance and daily test method in medical image department, part 2-5: Invariance test-medical image display device) has been established. This is a standard for the constancy test after the display is installed, and is intended to allow a user to perform a routine test. In this rule, test methods for various test items are defined by various methods such as visual inspection, luminance measurement, and dimension measurement.
[0005]
By the way, in this rule, in the test section for checking the invariance of the luminance of the display, the surface reflection luminance (herein referred to as Lamb) by the ambient light on the display surface is measured. It is described that this measurement is performed using a teleluminometer.
[0006]
However, the teleluminance meter required here is an expensive measuring instrument because of its extremely precise structure, and it is difficult to require all users who use the display to provide it. There is a problem that there is.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the circumstances as described above, and the purpose of the present invention is to use a teleluminance meter even for a user who does not have an expensive measuring instrument such as a telephotometer. It is an object of the present invention to provide a display QC method that enables measurement of luminance with an accuracy comparable to that obtained, and that can use this information to check variations in display performance of the display. .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the display luminance measurement method according to the present invention obtains the correspondence between the luminance measured by the telephotometer and the illuminance measured by the illuminometer on the surface of the display. The illuminance measured by the illuminometer is converted to the luminance measured by the telephotometer based on the correspondence.
[0009]
Here, in the display luminance measurement method according to the present invention, the correspondence between the luminance measured by the telephotometer and the illuminance measured by the illuminometer is the presence of ambient light measured with the display turned off. Based on brightness and illuminance in the presence of ambient light and illuminance in the absence of ambient light for multiple brightness level displays measured with the display powered on It is preferable that it is obtained.
[0010]
In the display luminance measurement method according to the present invention, it is preferable that the correspondence relationship between the luminance measured by the telephotometer and the illuminance measured by the illuminometer is stored in a table.
[0011]
The display QC method according to the present invention is a display QC method using the display luminance measurement method described above, and is converted from the measurement result of illuminance measured by the display luminance measurement method at a predetermined time. When the brightness of the display is not within a predetermined range, the brightness of the display is adjusted.
[0012]
Here, the display luminance measuring method described above or the display QC method using the same can be executed by computer program control, and the scope of rights of the present invention extends to such a program. Needless to say.
[0013]
In the display luminance measuring method and the display QC method using the same according to the present invention, it is important to use a relatively inexpensive illuminometer instead of an expensive telephotometer. This illuminometer is often provided for management of the work environment (room brightness, etc.) at each office, etc., and by using this, even without an expensive telephotometer, The objective can be achieved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a case where an LCD (liquid crystal display) is a measurement target will be described as an example.
[0015]
First, how to obtain the correspondence between the luminance measured with the telephotometer and the illuminance measured with the illuminometer on the surface of the display will be described with reference to the operation flow chart shown in FIG.
[0016]
First, zero calibration is performed on the telephotometer and the illuminometer to adjust the base point (step 20).
[0017]
Next, in a state where the power of the display to be measured is turned off, the luminance is measured in the presence of ambient light by the telephotometer and the illuminance is measured by the illuminometer (step 22).
[0018]
2A to 2D specifically show details of the measurement operation in step 22 described above. FIG. 2A is a diagram showing a state of measurement of luminance in the presence of ambient light by the telephotometer 10, and the telephotometer is in a state where the display 14 is turned off in the presence of ambient light. 10 is arranged in a direction substantially perpendicular to the surface of the display 14 and fixed with a tripod or the like, and the luminance of the surface 14 of the display 14 in the presence of ambient light (Lamb mentioned above) is shown. Yes.
[0019]
FIG. 2 (b) shows how the illuminance meter 12 is used to measure the illuminance at the center of the display 14 (hereinafter referred to as “Emb”) under the same environment as above. . Details of the structure of the illuminance meter 12 will be described later.
[0020]
2 (c) and 2 (d) show the measurement situation shown in FIGS. 2 (a) and 2 (b) as a side sectional view. The brightness of the telephotometer 10 (FIG. 2 (c)) and the illuminometer 12 (FIG. 2 (d)) when measuring the luminance (Lamb) in the presence and measuring the illuminance (Embb) by the illuminometer 12 This shows the arrangement status with respect to the surface of the display 14.
[0021]
As shown in FIG. 2D, in the measurement here, the illuminometer 12 is substantially used as it is. Note that this is a point that is greatly different from the method of arranging the illuminance meter 12a when measuring the luminance of the surface of the display 14, which will be described later.
[0022]
In step 24, from the luminance (Lamb) and illuminance (Eamb) obtained in step 22, the ratio ρ = Lamb / Eamba
Is stored in the storage unit.
[0023]
Next, with the power of the display 14 to be measured turned on, an achromatic color pattern (gray scale test pattern) having different predetermined brightness levels is displayed in order for each brightness level, and the telephoto brightness The luminance is measured by the meter 10 and the special luminance (actually illuminance) is measured by using the illuminometer 12a (step 26). Here, the number of brightness levels to be changed is preferably about 3 to 9, for example, but is not limited thereto.
[0024]
The illuminance meter 12a used here is elastic, such as rubber, around the illuminance meter 12 shown above to measure the illuminance in the absence of ambient light, as shown in FIG. In addition, a cylindrical light shielding member 16 formed of a material having appropriate hardness and light shielding properties is set. In other words, the integrated value of the luminance of the inner portion of the light shielding member 16 on the surface 14a of the display 14 is set. Is configured to be measurable. With this light shielding member 16, it is possible to measure the special luminance (in practice, illuminance) of the display with less error without being affected by ambient light.
[0025]
Further, as is clear from FIG. 4, the above-described light shielding member 16 can always set a certain height (that is, a distance from the surface 14 a of the display 14) with high reproducibility with respect to the surface 14 a of the display 14. In addition, since the angle of the display 14 with respect to the surface 14a can be set to be constant, it has an effect of enabling stable measurement.
[0026]
3A to 3D specifically show details of the measurement operation in step 26 described above. FIG. 3A shows a state in which a gray scale test pattern of a certain luminance level is displayed, the telephoto luminance meter 10 is arranged in a direction substantially perpendicular to the surface of the display 14, and is fixed with a tripod or the like. The state of measuring the luminance (L) of the surface of the spray 14 in this state is shown.
[0027]
FIG. 3B shows an illuminance at the center of the display 14 using the illuminance meter 12a provided with the light shielding member 16 as described above (E: as described later, this is a simulation). It shows how to measure the brightness.
[0028]
3 (c) and 3 (d) show the measurement states shown in FIGS. 3 (a) and 3 (b) as side sectional views, and the luminance (L ) And measurement of the illuminance (E) by the illuminance meter 12a, the disposition state of the telephoto luminance meter 10 (FIG. 3 (c)) and the illuminance meter 12a (FIG. 3 (d)) with respect to the surface of the display 14 Is shown.
[0029]
Next, in step 28, the luminance (L (x)) is obtained by associating the luminance (L) and the illuminance (E) measured in step 26 with each stage of the gray scale test pattern (the number of this stage is x). )) And illuminance (E (x)), the relationship between (L (x)) and (E (x)) is obtained, and a conversion table between them is created and stored in the storage unit.
[0030]
FIG. 5 shows an example of the relationship between the above-described luminance (L (x)) and illuminance (E (x)). The meaning of this graph is that the relationship between the luminance (L (x)) and the illuminance (E (x)) is not expressed by a simple expression. The correspondence between them should be finely tabulated by performing appropriate interpolation.
[0031]
In the graph of FIG. 5, L (x) does not become 0 because it is measured with a telephotometer and includes L (ie, Lamb) in the presence of ambient light. In addition, since the illuminometer measures the integrated value of the luminance from all directions, the LCD is affected by light leakage due to the viewing angle. For this reason, the conversion table needs to be created by measurement for each display having different viewing angle characteristics.
[0032]
The above is the description of how to obtain the correspondence between the luminance measured with the telephotometer and the illuminance measured with the illuminometer. According to such a method, from the illuminance value measured with the illuminometer, the measurement data with the telephotometer can be reproduced in a pseudo manner. There is an effect that it is possible to obtain luminance data that substantially matches the data measured by the telephotometer.
[0033]
In the following, an example of actual application to quality control of a display image on a display, so-called display QC, using the correspondence relationship between luminance (L (x)) and illuminance (E (x)) thus obtained. explain.
[0034]
FIG. 6 is an operation flow diagram of the display QC that uses the above-described luminance (pseudo luminance obtained by conversion from the illuminance measured using the illuminometer). Note that a table (specifically, a personal computer) that controls the operation of the display QC according to the present embodiment is created or calculated in advance, such as the table indicating the correspondence relationship and ρ (= Lamb / Eamb value). (So-called personal computer), which is hereinafter referred to as a display QC control device).
[0035]
When a predetermined period of time elapses (that is, when the time point at which the constancy test should be performed has arrived) (step 30), the display QC control device gives the display operator or the like the illuminance (Emb and E (x )) Measurement is instructed. An operator or the like who has confirmed the instruction executes measurement of illuminance (where illuminance E (x) is preferably 3 to 9 as described above) (step 32), and the data is displayed on the display QC. Input to the control unit.
[0036]
The display QC control device converts the data into luminance values (Lamb and L (x)) with reference to the value of ρ and the conversion table (step 34). Further, the display QC control device determines whether or not the luminance values (Lamb and L (x)) obtained by the conversion in step 34 are within the range of luminance values to be maintained by the display (step 36). .
[0037]
That is, first, the measured value of Emb at the time of the current measurement is converted into a value of Lamb using the value of ρ described above, and the converted value of Lamb is an initial value (hereinafter referred to as Lamb _0). Compare with For example, when α is a constant,
Lamb ₀ −α ≦ Lamb ≦ Lamb ₀ + α (1)
If is established, it is determined that Lamb has not substantially changed, and the process proceeds to the next determination.
[0038]
In the determination of the second stage, it is determined whether or not each value of L (x) obtained by conversion from E (x) is within the range of luminance values to be maintained by the display. This determination also compares the value of L (x) with the initial value (hereinafter referred to as L ₀ (x)), similarly to the determination of Lamb described above. For example, when β is a constant,
L ₀ (x) −β ≦ L (x) ≦ L ₀ (x) + β (2)
If is established, it is determined that L (x) has not substantially changed, and the test is terminated without taking any particular action.
[0039]
On the other hand, when the above formula (1) is not satisfied (N in step 36), the ambient light level, for example, the room illumination is adjusted (step 38), and the surface reflection luminance is returned to a predetermined range. After the adjustment, the above-described measurement of Eamb and E (x) is executed again. Further, even if the expression (1) is satisfied, if the following expression (2) is not satisfied, the brightness of the display is adjusted at this time (step 38), and E (x) → L The conversion to (x) and subsequent steps will be executed again.
[0040]
In each of the above determinations, if the value of Lamb or L (x) is within a predetermined range, the test result is recorded and the process returns to the standby state without any particular action (step 36, Y → step 30).
[0041]
If the luminance value obtained in step 34 is out of the range of the luminance value to be maintained by the display (N in step 36), the luminance of the display is adjusted so as to return to the predetermined range ( In step 38), adjustment may be performed by a method such as using a brightness adjustment table prepared in advance. In checking the adjustment result at this time, the result of the illuminance measurement by the illuminometer may be referred to.
[0042]
In the present embodiment, the illuminance measured by the illuminometer 12a within the practically necessary range using the previously obtained ρ (= Lamb / Eamba value) and the conversion table from the illuminance E to the luminance L. An example is shown in which the value of E is converted into the luminance L measured by the telephotometer 10 and the luminance variation of the display is checked based on this. Can also be implemented.
[0043]
7, information corresponding to a plurality of displays 44a, 44b,... In the memories 42a, 42b,. (rho or luminance / illuminance conversion table, etc.) are individually stored and managed, the display QC is displayed for a plurality of displays 44a, 44b,... It becomes possible to execute.
[0044]
In this case, the plurality of displays 44a, 44b,... Are different in display color (monochrome and color, for example), different in display principle (CRT and LCD, etc.), and different in surface treatment (anti-glare treatment). The display may be of various types such as those having different viewing angles or the like, or having different viewing angles, and can be handled by information corresponding to them.
[0045]
In FIG. 7, reference numeral 46 indicates an illuminance meter used online or offline, and reference numeral 48 indicates a telephoto luminance meter specially connected when calibration is performed.
[0046]
Each of the above-described embodiments shows an example of the present invention, and the present invention should not be limited to this, and appropriate modifications or improvements may be made without departing from the scope of the present invention. Needless to say, it is good.
[0047]
For example, in the description of the method of implementing the display QC using the correspondence between the luminance measured by the telephotometer and the illuminance measured by the illuminometer shown in the above embodiment, in order to reduce the burden of the operator's operation as much as possible, Although an example in which the method of the invention is executed by computer program control has been shown, these may be replaced by operator operations.
[0048]
Needless to say, the scope of rights of the present invention extends to a program for executing the method of the present invention by a computer as described above.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, even a user who does not have an expensive measuring instrument such as a teleluminance meter can obtain the accuracy obtained when using the teleluminance meter by using the illuminance meter. The luminance can be measured with the same accuracy as the above, and it is possible to check the change in display performance of the display using this information.
[Brief description of the drawings]
FIG. 1 is an operational flowchart showing how to obtain a correspondence relationship between luminance measured by a telephotometer and illuminance measured by an illuminometer according to an embodiment of the present invention.
2A to 2D are explanatory views showing details of a measurement operation in step 22 in FIG.
FIGS. 3A to 3D are explanatory diagrams showing details of a measurement operation in step 26 in FIG. 1;
FIG. 4 is a cross-sectional view showing the structure of an illuminometer.
FIG. 5 is a graph showing an example of the relationship between luminance (L (x)) and illuminance (E (x)).
FIG. 6 is an operation flowchart of the display QC according to an embodiment of the present invention.
FIG. 7 is a block diagram showing a schematic configuration of a display QC system according to an embodiment of the present invention.
[Explanation of symbols]
10, 48 Telephotometer 12, 12a, 46 Illuminance meter 14, 44a, 44b, ... Display 14a Display surface 16 Shading member 20-28, 30-38 Processing step 40 Display QC controller 42a, 42b, ... Memory

Claims (6)

On the surface of the display monitor, find the correspondence between the luminance measured with the telephotometer and the illuminance measured with the illuminometer,
In actual measurement, the luminance measurement method for a display monitor is characterized in that the illuminance measured by the illuminance meter is converted into the luminance measured by a teleluminance meter based on the correspondence relationship. The correspondence between the luminance measured by the telephotometer and the illuminance measured by the illuminometer is
Brightness and illuminance in the presence of ambient light, measured with the display monitor power off,
Obtained based on the luminance in the presence of ambient light and the illuminance in the absence of ambient light for multiple brightness level displays measured with the display monitor power on. The luminance measurement method for a display monitor according to claim 1. 3. The display monitor luminance measurement method according to claim 1, wherein a correspondence relationship between the luminance measured by the telephotometer and the illuminance measured by the illuminometer is stored in a table. The program for performing the brightness | luminance measuring method of the display monitor of any one of Claims 1-3 by computer control. A display QC method using the display monitor luminance measurement method according to claim 1,
If the brightness of the display monitor converted from the illuminance measurement result measured by the display monitor brightness measurement method at a predetermined time is not within a predetermined range, the display monitor A display QC method characterized by adjusting brightness. The program for performing the display QC method of Claim 5 by computer control.

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