JP2011169842A - Flicker measuring method and device thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flicker measuring method capable of easily measuring flicker superposed on an image, with a simple configuration. <P>SOLUTION: The flicker measuring method for measuring flicker of an image displayed on a display device 10 includes the image pickup control step which causes an imaging part 100 to pick up an image with a time interval longer than the cycle of flicker to be measured by the amount of predetermined additional time (exposure time), for obtaining imaging signals, and the flicker waveform calculation step for calculating the waveform of flicker with the light intensity in the acquired imaging signal as data of each additional time (exposure time). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flicker measurement method and apparatus for measuring flicker of an image displayed on an image display surface.

2. Description of the Related Art Conventionally, various methods for measuring flicker at multiple points in a display area where an image is displayed in a display device such as a projector or a liquid crystal display device are known (for example, see Patent Document 1).
In the method for measuring flicker described in Patent Document 1, projection light from a projector projected on a screen is received by an optical sensor attached to the screen. The optical signal output from the optical sensor is filtered by a band pass filter. Further, the period waveform of the flicker caused by the AC voltage that drives the liquid crystal panel of the projector is analyzed to detect two different imaging times, and the screen display area is imaged by the video camera. A configuration is adopted in which images taken at different imaging times are subjected to differential processing, and the flicker of the liquid crystal panel is calculated at all points in the display area on the screen.

JP 2006-91149 A

The conventional method described in Patent Document 1 requires an optical sensor that receives projection light. For this reason, for example, when an optical sensor such as a liquid crystal display device cannot be installed, flicker cannot be measured, and there is a disadvantage that the range of use is limited. Furthermore, a band-pass filter that filters the optical signal from the optical sensor, a circuit that analyzes the flicker periodic waveform caused by the AC voltage from the filtered optical signal, and detects two imaging times are required. For this reason, the apparatus configuration is complicated, and it is difficult to reduce the apparatus cost.
SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a flicker measurement method and apparatus capable of measuring flicker easily superimposed on an image with a simple configuration.

  The flicker measurement method of the present invention is a flicker measurement method for measuring the flicker of an image displayed on a display device, wherein the image is captured by the imaging device at a time interval longer by a predetermined additional time than the cycle of the flicker to be measured. An image capturing control process for acquiring an imaging signal generated by sequentially capturing images, and a flicker for calculating the flicker waveform using the light intensity in the imaging signal acquired in the image capturing control process as data for each additional time And a waveform calculation step.

In the present invention, an image is picked up by an image pickup device at a time interval that is longer by a predetermined additional time than the flicker cycle assumed to be superimposed on the image as a measurement object. The flicker waveform is obtained by using the light intensity in the imaging signal obtained by imaging as data of the additional time. For example, assuming a graph in which time is set on the horizontal axis and light intensity is set on the vertical axis, the light intensity is sequentially plotted at intervals of the additional time, and the plotted points are connected to form a flicker waveform. Can be sought.
As a result, when there is flicker with a period set as a measurement target, the intensity of light of an image captured at a time interval different from the flicker period becomes a different time intensity within one period of the flicker. By plotting the light intensity for each additional time, the flicker waveform is reproduced.
Therefore, in the present invention, the flicker waveform can be reproduced if the image is captured at the timing when the image is set using the imaging device (the set flicker cycle + the additional time interval). Therefore, the flicker waveform can be recognized at any point in the image display area based on the imaging signal at the corresponding point in the captured display area. Therefore, it is not necessary to separately provide an optical sensor or the like for analyzing the flicker cycle, and the configuration can be simplified. Further, since no optical sensor is required, there are few restrictions on the measurement environment and the device under measurement, the versatility of measurement can be improved, and flicker superimposed on the image can be easily measured.
The intensity of light in the present invention is not limited to lightness and luminance, but can be an intensity representing light characteristics such as saturation. In addition to images displayed by self-emission such as liquid crystal panels, organic EL (Electro Luminescence) panels, and PDPs (Plasma Display Panels), images projected from the projector onto the screen are also displayed on the display device. Can be targeted.

In the flicker measurement method of the present invention, the image capturing control step calculates the exposure time of each image capturing unit by dividing the flicker cycle set as the measurement target by the set sampling number as the additional time. It is preferable that an exposure time is set as the additional time, and the images are sequentially captured by the imaging device.
In the present invention, an exposure time obtained by dividing a set flicker cycle by a set sampling number is set as an additional time, and images are taken at time intervals longer than the flicker cycle by the exposure time. As a result, the intensity of light of the captured image is used as data for each exposure time, the flicker waveform can be reproduced with high accuracy, and the expected flicker can be measured well.

In the flicker measurement method of the present invention, it is preferable that the flicker waveform calculating step calculates a flicker waveform for each divided region obtained by dividing the image in the imaging signal into a plurality of regions.
In the present invention, the flicker waveform is calculated for each divided region obtained by dividing the image in the imaging signal into a plurality of regions. Thus, even when flickers that are partially different in the image display area are superimposed on the image, the flicker waveform can be recognized for each divided area. For this reason, a better image display state can be provided by adjusting the display state of the display device for each divided region.

In the flicker measuring method of the present invention, it is preferable that the flicker waveform calculating step calculates a waveform amplitude with respect to a waveform average of light intensity in the calculated flicker waveform as a flicker value.
In the present invention, the waveform amplitude of the flicker waveform is calculated to obtain the flicker value with respect to the waveform average which is the average value of the light intensity in the calculated flicker waveform. In this way, by calculating the flicker value, the size of the flicker superimposed on the image can be evaluated. For example, by setting a threshold value corresponding to the size of the flicker to be visually recognized, the display state of the display device Can be evaluated appropriately.

  The flicker measuring apparatus of the present invention is a flicker measuring apparatus that measures flicker of an image displayed on a display device, and is a predetermined addition based on an imaging device that captures the image and a flicker cycle assumed for the purpose of measurement. Image capturing control means for acquiring an imaging signal generated by sequentially capturing the images with the imaging device at a time interval long by time, and the intensity of light in the imaging signal acquired by the image capturing control means, And flicker waveform calculating means for sequentially plotting each additional time and calculating the flicker waveform.

This invention uses the flicker measurement method described in the present invention as an apparatus configuration, and has the same effects as the optical flicker measurement method of the present invention.
That is, the image capturing control unit uses the image capturing control unit to set the exposure time set based on the flicker cycle assumed to be superimposed on the image for the purpose of measurement and a predetermined additional time longer than the assumed flicker cycle. Take an image. The intensity of the light of the imaging signal obtained by imaging is sequentially plotted for every additional time in the time interval by the flicker waveform calculating means, and the assumed flicker waveform is calculated.
Thus, an image may be picked up using an image pickup apparatus, and the flicker waveform can be recognized at any point in the image display area based on the image pickup signal at the corresponding point in the picked-up display area. For this reason, it is not necessary to separately provide an optical sensor or the like for measuring an image at an arbitrary point, and the configuration can be simplified. Furthermore, there is no conventional measurement restriction limited to a measurement environment in which an optical sensor can be used, and measurement versatility can be easily improved, and flicker superimposed on an image can be easily measured.

In the flicker measuring apparatus according to the present invention, the image capturing control means calculates a shutter timing calculating means for calculating an exposure time and the time interval to be imaged by the imaging apparatus based on a flicker period set and inputted, and the exposure A high-precision timer trigger unit that outputs to the imaging device a trigger signal that causes the imaging device to capture the image at the time and the time interval, and the imaging device is output from the high-precision timer trigger unit It is preferable that the image is captured at the exposure time and the time interval by a trigger signal.
In the present invention, the exposure time to be imaged by the imaging apparatus and the time interval are calculated by the shutter timing calculation means based on the flicker cycle set and inputted. A trigger signal that causes the imaging device to capture an image at the calculated exposure time and time interval is output to the imaging device by the high-precision timer trigger unit. Then, an image is picked up by the image pickup device with this trigger signal. For this reason, an image can be taken with the exposure time and time interval timed with high accuracy. Therefore, the flicker waveform can be reproduced with high accuracy by plotting the light intensity of the imaging signal obtained by this high-accuracy imaging.

The block diagram which shows schematic structure of the flicker measuring apparatus of this invention. The graph which shows the relationship between the measured value which measured the display area of the image of the display apparatus with the said flicker measuring apparatus, and flicker. The conceptual diagram which shows the image in the said measured value. The graph which shows the concept which calculates the waveform of the said flicker. The flowchart which shows the operation | movement of the measurement process for measuring the flicker superimposed on the said image. The conceptual diagram which shows the division area which divided | segmented the image in the said measured value into plurality. The conceptual diagram which calculates the waveform of the flicker which is a modification of this invention on other conditions.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
In the present embodiment, a configuration in which a predetermined color pattern is displayed as an image of the display device is illustrated, but the present invention is not limited to this. For example, the content of an image to be measured, such as a simple monochrome display or a white image with a predetermined brightness, is set as appropriate.

[Configuration of Flicker Measuring Device]
As shown in FIG. 1, the flicker measuring apparatus 1 is an apparatus that takes an image projected on a screen 12 from a display device 10, for example, a projector 11 that is a display device, and measures a flicker component that is noise included in the image. is there.
The flicker measuring apparatus 1 includes an imaging unit 100 as an imaging device that captures an image, and an image processing unit 200.

The imaging unit 100 includes a CCD (Charge Coupled Device) 110, an automatic gain controller (AGC) 120, an A / D converter (Analog to Digital Converter) 130, and the like.
The CCD 110 forms an image through an iris that adjusts the amount of incident light, for example, and performs photoelectric conversion to generate an imaging signal.
The AGC 120 gives a gain to the imaging signal generated by the CCD 110.
The A / D converter 130 converts the imaging signal from the AGC 120 into a digital signal and outputs it as a measurement value.

The image processing unit 200 uses, for example, a personal computer, and calculates a flicker component to be superimposed on the image of the display device 10 based on the measurement value generated by the imaging unit 100.
As the image processing unit 200, for example, a personal computer or the like is used. An input operation unit 201, a storage unit 202, and a high-precision timer trigger unit 203 are connected to the image processing unit 200.

The input operation unit 201 is configured so that an operator can perform an input operation using, for example, a mouse, a keyboard, a touch panel provided on the monitor of the flicker measuring apparatus 1, voice input, or the like.
The input operation unit 201 is connected to the image processing unit 200 and causes the image processing unit 200 to set and input various signals according to the input operation by the worker.

As the storage unit 202, for example, a memory or a drive using various recording media is used. The storage unit 202 is connected to the image processing unit 200 so that the image processing unit 200 can read and record various information and measurement values.
The storage unit 202 also stores various programs developed on an OS (Operating System) that controls the entire flicker measuring apparatus 1, for example.

The high-precision timer trigger unit 203 includes a crystal resonator, for example, and is configured to measure a very short time interval such as 1/1000 second or 1/2000 second with high accuracy.
The high-precision timer trigger unit 203 is connected to the image processing unit 200 and the imaging unit 100 so as to be able to transmit and receive various types of information. As will be described in detail later, the high-precision timer trigger unit 203 counts the trigger signal with high accuracy based on information on the imaging conditions from the image processing unit 200 and outputs the trigger signal to the imaging unit 100 for imaging.

The image processing unit 200 includes, for example, a CPU, and various programs that are developed on an OS that controls the entire flicker measuring apparatus 1 are configured.
That is, the image processing unit 200 includes, as various programs, a shutter timing calculation unit 210, a trigger unit control unit 220 as an image capturing control unit, a flicker waveform calculation unit 230, and the like.

The shutter timing calculation unit 210 sets an imaging condition that causes the imaging unit 100 to capture an image and generate a measurement value based on a flicker period that is assumed to be superimposed on the image as a measurement target.
The shutter timing calculation unit 210 includes a sampling number setting unit 211, a flicker synchronization setting unit 212, an exposure time setting unit 213, and an imaging timing setting unit 214.

The sampling number setting unit 211 sets a sampling number that is the number of times the imaging unit 100 captures an image in response to an input operation of the input operation unit 201 by the operator. The imaging number setting signal regarding the set sampling number is appropriately stored in the storage unit 202.
As the number of samplings, for example, it is preferable to measure 6 times or more. That is, when the number of samplings is smaller than six, the number of flickers assumed is smaller than six cycles, and the number of plots when reproducing the flicker waveform, which will be described later, is reduced. As a result, the accuracy of the flicker waveform to be reproduced is disadvantageously lowered. Therefore, in order to calculate the flicker waveform with a certain degree of accuracy, it is preferable to set the flicker waveform to 6 times or more.

The flicker synchronization setting unit 212 is configured such that the operator performs an input operation of an assumed flicker cycle to be measured by the input operation unit 201, so that the flicker cycle corresponding to the input operation is set.
Here, for example, when it is assumed that the flicker shown in the waveform diagram of the two-dot chain line in FIG. 2 is superimposed on the image, the assumed flicker period T2 [msec] is the time corresponding to one flicker period. Is long.
Then, the cycle setting signal related to the set cycle T2 is appropriately stored in the storage unit 202.

The exposure time setting means 213 sets the exposure time T1 [msec] shown in the pulse form of FIG. 2 based on the assumed flicker period T2. In other words, the exposure time setting means 213 sets based on the sampling number set by the sampling number setting means 211 and the flicker synchronization setting means 212 and the flicker cycle T2. Specifically, the exposure time T1 is represented by an assumed flicker period T2 with respect to the sampling number N, for example, as shown in the following equation (1), where N is the sampling number.
[Formula 1]
T1 = T2 / N (1)
An exposure time setting signal related to the set exposure time T 1 is stored in the storage unit 202 as appropriate.

The imaging timing setting means 214 sets the time interval T3 of the exposure time T1, which is the imaging interval shown in FIG. 2, longer than the cycle T2 by a predetermined additional time based on the assumed flicker cycle T2. Specifically, as shown in the following formula (2), the imaging timing setting unit 214 sets the exposure time T1 longer than the cycle T2 by a predetermined additional time.
[Formula 2]
T3 = T1 + T2 (2)
A time interval setting signal related to the set time interval T3 is stored in the storage unit 202 as appropriate.

The trigger unit control unit 220 transmits various signals related to the imaging condition set by the shutter timing calculation unit 210 to the high-precision timer trigger unit 203 and controls the imaging unit 100 to capture an image.
Specifically, the high-precision timer trigger unit 203 that has received various signals of the imaging conditions from the trigger unit control unit 220 controls the imaging unit 100 according to the imaging conditions to capture an image, and generates a measurement value that is an imaging signal. Let
Here, when capturing an image, for example, as shown in FIG. 3, at least the entire area of the image 13 of the display device 10 is included. Thus, the flicker component superimposed on the image 13 can be measured over the entire area of the image 13.
The measurement values generated by the imaging unit 100 are appropriately acquired by the image processing unit 200 and sequentially stored in the storage unit 202.

The flicker waveform calculation means 230 uses the flicker intensity of the measurement value acquired by capturing the image 13 (the magnitude of the measurement value) as data for each exposure time T1, which is a predetermined additional time in the time interval T3. Calculate the waveform.
Specifically, the flicker waveform calculation means 230 extracts the light intensity of the image 13 portion in the measurement value by, for example, binarization processing. The light intensity is sequentially plotted for each exposure time T1, as shown in FIG. That is, plotting is performed with the exposure time T1 having a time length shifted from the flicker cycle T2 in the time interval T3 shown in FIG. 2, and as shown in FIG. 4, the measurement is performed at the exposure time T1 intervals packed by the flicker cycle T2. Plot the values. By connecting the plotted points, the flicker waveform diagram indicated by a two-dot chain line in FIGS. 2 and 4 is reproduced. Then, the flicker waveform calculation means 230 calculates the flicker waveform formula from the reproduced waveform diagram.
Further, the flicker waveform calculating means 230 calculates the DC component and the AC component shown in FIG. 4 based on the waveform formula that is the calculated flicker waveform. That is, the flicker waveform calculation means 230 calculates a waveform average (DC component) and a waveform amplitude (AC component) that are average values of light intensity in the flicker waveform. Then, the flicker waveform calculation means 230 calculates a flicker value f that is the degree of flicker represented by the AC component with respect to the DC component, as shown by the following equation (3).
[Formula 3]
f = AC component / DC component

[Flicker measurement method using flicker measurement device]
Next, a method for measuring the flicker superimposed on the image 13 using the flicker measuring apparatus 1 will be described with reference to the drawings.
FIG. 5 is a flowchart showing an operation of measurement processing for measuring flicker superimposed on an image. FIG. 6 is a conceptual diagram showing a concept of dividing an image of measurement values into a plurality of divided regions.

First, in the measurement process, as shown in FIG. 5, a measurement screen display process is performed (step S1).
That is, in the measurement image display process of step S1, as shown in FIG. 1, the display device 10 and the flicker measurement device 1 are set at predetermined positions. In setting, for example, the display device (projector) 11 of the display device 10 for measuring using a transport device or the like is automatically installed at a predetermined position shown in FIG. 1 or manually set by an operator. May be.
When the image processing unit 200 of the flicker measuring apparatus 1 recognizes the signal indicating that it has been set, the image processing unit 200 receives the display signal indicating that the predetermined image 13 for measurement is being displayed from the display device 10, thereby The display screen imaging process, which is the process of (2), is performed.
In addition, the display signal may be received by, for example, a setting input by an operator in addition to a configuration in which the display signal is directly received from the display device 10.

In the display screen imaging process in step S2, the exposure time T1 and the time interval T3 are calculated by the shutter timing calculation unit 210 based on the sampling number N set and input in advance by the operator and the assumed flicker period T2. . Then, the trigger unit control means 220 transmits the calculated exposure time T1 and time interval T3 to the high-precision timer trigger unit 203 as an imaging condition. The high-precision timer trigger unit 203 generates a trigger signal timed with high accuracy corresponding to the transmitted exposure time T1 and time interval T3, and outputs this trigger signal to the imaging unit 100. Based on the output trigger signal, the imaging unit 100 causes the image 13 to be captured at a highly accurate exposure time T1 and time interval T3. The measurement values generated by this imaging are sequentially acquired by the image processing unit 200 and stored in the storage unit 202.
When the image processing unit 200 recognizes that the measurement value has been acquired with the set sampling number N, the image processing unit 200 ends the display screen imaging process in step S2.

After the display screen imaging process in step S2, a display area extraction process is performed (step S3).
The display area extraction process in step S3 is performed by, for example, binarization processing by the flicker waveform calculation means 230, as shown in FIG. 3, to display the display area of the captured image 13 at the measured values t0, t1,. Extract.
The extracted signal values of the image 13 are sequentially stored in the storage means 202 in association with the measured values t0, t1,.

The signal value of the image 13 extracted in the display area extraction process in step S3 is processed in the area averaging process which is the next process (step S4).
In the area averaging process in step S4, the image 13 extracted in step S3 by the flicker waveform calculation means 230 is divided into a plurality of divided areas a0 and a1 in a predetermined number and area as shown in FIG. 6, for example. ,..., An are divided. These divided areas a0, a1,..., An are stored in the storage means 202 in a data structure linked to the measured values t0, t1,.
Note that the process of dividing the divided areas a0, a1,..., An is not limited to the configuration performed after the process of extracting the images 13 for all the measured values t0, t1,. For example, the process of sequentially dividing the extracted image 13 may be performed in parallel.
Then, the flicker waveform calculating means 230 extracts each pixel value in each divided area a0, a1,..., An and calculates an average value of the extracted pixel values. These average values are stored in the storage means 202 in a data structure linked to each of the divided areas a0, a1,..., An of the measured values t0, t1,..., TN, and the intra-area averaging process in step S4 is completed. To do.

After the intra-region averaging process in step S4 is completed, a flicker periodic waveform reproduction process is performed (step S5).
In the flicker periodic waveform reproduction process in step S5, the flicker waveform calculation means 230 calculates the flicker waveform for each of the divided areas a0, a1,..., An in step S4. That is, the flicker waveform calculating means 230 sequentially plots the light intensity, which is the signal value for each of the divided areas a0, a1,..., An in step S4, for each exposure time T1, as shown in FIG. The flicker waveform shown by the two-dot chain line in FIGS. 2 and 4 is reproduced. The flicker waveform formula is calculated from the reproduced waveform.
Thereafter, the flicker waveform calculation means 230 calculates the DC component and the AC component shown in FIG. 4 based on the calculated flicker waveform. That is, the flicker waveform calculation means 230 calculates a waveform average (DC component) and a waveform amplitude (AC component) that are average values of light intensity in the flicker waveform. Then, the flicker waveform calculation means 230 calculates the flicker value f shown by the above-described equation (3), and ends the flicker period waveform reproduction process in step S5.
Note that after the flicker value f is calculated, for example, it may be output and notified to the worker, or the display state of the display device 10 may be controlled, and then step S5 may be terminated.
When the image processing unit 200 recognizes that the flicker period waveform reproduction process of step S5 has been completed, if there is a process of reproducing the flicker waveform or calculating the flicker value f in the next different period T2, the above processing is performed. Repeat the process. On the other hand, if there is no next process, the measurement process is terminated.

[Effects of Embodiment]
According to 1st embodiment mentioned above, there exist the following effects.
(1) The image 13 is imaged using the imaging unit 100 at a time interval T3 that is longer than the flicker period T2 that is assumed to be superimposed on the image 13 for measurement purposes by an exposure time T1 that is a predetermined additional time. The light intensity, which is the signal value of the measurement value obtained by this imaging, is plotted sequentially for each exposure time T1, which is an additional time.
Accordingly, when flicker having a period set as a measurement target exists, the light intensity of the image 13 captured at a time interval T3 different from the flicker period T2 is different from the intensity of different time within one flicker period. Become. On the other hand, when there is no flicker in the period set as the measurement target, the light intensity of the image 13 is constant, and there is no difference in the light intensity even at different shooting timings. Therefore, by plotting the light intensity for each exposure time T1, which is an additional time that deviates from the flicker period T2 in the imaging time interval T3, if flicker is present, a predetermined waveform diagram is reproduced, and the flicker is reproduced. If it does not exist, a linear waveform diagram having a constant value is reproduced.
Therefore, in the present embodiment, if the image capturing unit 100 is used to capture an image 13 at the set timing (set flicker period T2 + exposure time T1 that is an additional time), the flicker waveform can be reproduced. Therefore, the flicker waveform can be recognized at any point in the display area of the image 13 based on the imaging signal that is the pixel value of the image 13 at the corresponding point in the captured display area. Therefore, it is not necessary to separately provide an optical sensor or the like for analyzing the flicker period T2, and the configuration can be simplified. Further, since no optical sensor is required, there are few restrictions on the measurement environment and the device under measurement, the versatility of measurement can be improved, and flicker superimposed on the image 13 can be easily measured.

(2) In the present embodiment, one cycle of flicker set as a measurement target is divided by the set sampling number N to set the exposure time T1 to be imaged by the imaging unit 100, and the flicker cycle T2 to be set The image 13 is captured at a time interval T3 that is longer by the exposure time T1.
For this reason, the light intensity of the image 13 taken at each exposure time T1 is plotted, the flicker waveform diagram can be reproduced with high accuracy, and the measurement target flicker can be measured well.

(3) In this embodiment, the flicker waveform is reproduced by plotting the light intensity of the measured value for each exposure time T1.
For this reason, it is possible to easily measure whether or not the flicker of the set cycle T2 is superimposed on the image 13 by appropriately changing the expected flicker cycle T2.

(4) In the present embodiment, the flicker waveform is calculated for each of the divided areas a0, a1,.
As a result, even when flicker partially different in the display area of the image 13 is superimposed on the image 13, the flicker waveform diagram can be reproduced and recognized for each of the divided areas a0, a1,. Therefore, by adjusting the display state of the display device 10 for each of the divided areas a0, a1,..., An, a good display state of the image 13 without flicker can be provided.

(5) Further, a flicker waveform diagram is reproduced for each of the divided areas a0, a1,..., An using the average value of the pixel values in each divided area a0, a1,.
Therefore, there is no influence of errors such as erroneous display of pixels in the divided areas a0, a1,..., An, and a favorable flicker waveform diagram can be reproduced for each of the divided areas a0, a1,.

(6) In this embodiment, the waveform amplitude (AC component) of the flicker waveform formula is calculated with respect to the waveform average (DC component) which is the average value of the light intensity in the flicker waveform formula of the reproduced waveform diagram. Thus, the flicker value f which is the degree of flicker is calculated.
Thus, by calculating the flicker value f, the size of the flicker superimposed on the image 13 can be evaluated. Therefore, for example, the display state of the display device 10 can be appropriately evaluated by setting a threshold corresponding to the size of the flicker to be visually recognized.

(7) Using the high-accuracy timer trigger unit 203, the image capturing unit 100 captures the image 13 at the exposure time T1 and the time interval T3 measured with high accuracy.
Therefore, the flicker waveform can be reproduced with high accuracy by the process of plotting the measurement values obtained by imaging. Therefore, the flicker superimposed on the image 13 can be measured with high accuracy.

[Modification of Embodiment]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the flicker measuring device 1 is provided with a configuration that adjusts the drive circuit of the display device 10 based on the flicker calculated by the flicker waveform calculating means 230 so that a good image 13 from which the flicker is removed can be displayed. It is good. The flicker calculation result may be output by a monitor, a printing device, or the like provided in the flicker measuring apparatus 1, and the display device 10 may be adjusted by an operator.

Alternatively, the assumed flicker period T2 may be sequentially measured at different periods T2. For example, an operator sets and inputs a cycle range and a cycle interval as a measurement range, and sets a flicker cycle T2 to be measured for each cycle interval within the set and input cycle range. Then, the exposure times T1 and T3 may be appropriately set and measured, and the flicker waveform may be calculated at each cycle T2 to determine the presence or absence of flicker.
With this configuration, it is possible to easily measure whether or not an unknown flicker is superimposed on the image 13.

The time interval T3 set by the imaging timing setting unit 214 is exemplified as a time length longer by the exposure time T1 than the assumed flicker cycle T2, but is not limited thereto. For example, the predetermined additional time may be twice as long as the exposure time T1. In this case, for example, as shown in FIG. 7, the plot is in a state where the interval of the exposure time T1 is vacated by the light intensity indicated by the bar graph.
In this way, a value that can calculate the flicker waveform when plotted is sufficient. That is, any number other than a multiple of the flicker period T2 may be used. Note that if the additional time for shifting from the flicker period T2 becomes longer as the time interval T3, the measurement time becomes longer. Therefore, the additional time should be shorter.

  Although the high-precision timer trigger unit 203 has been described, for example, the imaging unit 100 may be omitted as long as the imaging unit 100 can capture images with a high-precision exposure time T1 and time interval T3. In this case, for example, control of the imaging unit 100 by the trigger unit control unit 220 can be exemplified.

Although the display area of the image 13 is divided and the flicker waveform is reproduced for each of the divided areas a0, a1,..., An, the flicker waveform may be reproduced for the entire display area of the image 13.
Specifically, for example, the average value of all the pixel values in the display area of the image 13 or the average value of a plurality of arbitrary pixel values is calculated as the light intensity, and sequentially plotted with a predetermined additional time length to flicker. It is sufficient to reproduce the waveform.

  DESCRIPTION OF SYMBOLS 1 ... Flicker measuring apparatus, 10 ... Display apparatus, 13 ... Image, 100 ... Imaging part as imaging apparatus, 200 ... Image processing part which can function as flicker measuring apparatus, 220 ... Trigger part control means as image imaging control means, 230 flicker waveform calculation means, a0, a1,..., An ... divided areas, f ... flicker values, t0, t1, ..., tN ... measured values as imaging signals, T1 ... exposure time as additional time, T2 ... flicker Period, T3 ... time interval

Claims (6)

A flicker measurement method for measuring flicker of an image displayed on a display device,
An image capturing control step of acquiring an imaging signal generated by sequentially capturing the images with an imaging device at a time interval longer than a period of the flicker to be measured by a predetermined additional time;
And a flicker waveform calculating step of calculating the flicker waveform using the intensity of light in the image pickup signal acquired in the image pickup control step as data for each additional time. The flicker measurement method according to claim 1,
In the image capturing control step, as the additional time, the period of flicker set as a measurement target is divided by the set sampling number to obtain the exposure time of each imaging own, and this exposure time is set as the additional time Then, the image is sequentially picked up by the image pickup device. In the flicker measurement method according to claim 1 or 2,
In the flicker waveform calculating step, a flicker waveform is calculated for each divided region obtained by dividing the image in the imaging signal into a plurality of regions. In the flicker measurement method according to any one of claims 1 to 3,
In the flicker waveform calculating step, a flicker value is calculated as a flicker value with respect to a waveform average of light intensity in the calculated flicker waveform. A flicker measuring device for measuring flicker of an image displayed on a display device,
An imaging device for capturing the image;
Image capturing control means for acquiring an imaging signal generated by sequentially capturing the images with the imaging device at a time interval longer than a period of the flicker to be measured by a predetermined additional time;
Flicker waveform calculation means for calculating the flicker waveform as the data of the additional time, the intensity of light in the image pickup signal acquired by the image pickup control means;
A flicker measuring apparatus comprising: In the flicker measuring device according to claim 5,
The image capturing control means includes
Shutter timing calculation means for calculating the exposure time and the time interval to be imaged by the imaging device based on the flicker period set and input;
A high-precision timer trigger unit that outputs a trigger signal for capturing the image by the imaging device to the imaging device at the exposure time and the time interval;
The flicker measurement apparatus, wherein the image device captures the image at the exposure time and the time interval by the trigger signal output from the high-precision timer trigger unit.

Images