Light measurement device, light measurement method, data processing device, and program

Abstract

Provided are an optical measurement device, an optical measurement method, a data processing device, and a program, capable of generating data that is a stimulus value that takes into account the time response of an eye and suppresses waveform distortion, capable of performing good flicker measurement, and also capable of coping with a measurement target object having a non-periodic light emission waveform. A stimulus value acquisition unit (20) receives light from a measurement target object to continuously acquire intensities corresponding to stimulus values at constant time intervals; a response characteristic acquisition unit (32) acquires a pulse response characteristic from a storage unit (31) that stores a pulse response characteristic corresponding to a visual stimulus response; and a digital filter processing unit (32) performs digital filter processing on continuous data of the acquired stimulus value intensities using the acquired pulse response characteristic to generate data on which a visual stimulus response is superimposed.

Description

Technical Field

[0001] The present invention relates to an optical measurement apparatus, an optical measurement method, a data processing apparatus, and a program suitable for measuring the flicker of objects such as displays. Background Technology

[0002] As the functionality and performance of displays improve, the emission waveforms become more complex. For example, in the case of OLED (Organic Light-Emitting Diode) displays, in order to achieve faithful color reproduction, emission control is employed that combines amplitude modulation and pulse width modulation for grayscale control, resulting in a generalized emission waveform with high amplitude and complex shape.

[0003] In addition, in recent years, displays with VRR (Variable Refresh Rate) functionality have been developed. In these displays, the refresh rate switches dynamically and non-periodically, and transient responses are observed in the emission waveform starting from the switching point, making the emission waveform increasingly complex.

[0004] As the emission waveform becomes more complex, flicker (visible flicker) becomes more noticeable. This becomes a quality issue for displays.

[0005] As a light measurement device for measuring the basic properties of objects such as displays, there are known display color analyzers (for example, the CA-410 manufactured by Konica Minolta Corporation). Such display color analyzers have an internal light sensor that can measure not only color and brightness, but also light waveform and flicker.

[0006] There are generally two methods for acquiring the amount of light from the object being measured: successive acquisition of instantaneous values ​​and integral acquisition of integral values ​​over a predetermined time. They share the following characteristics: successive acquisition excels in high-speed performance, while integral acquisition excels in low-brightness measurement performance.

[0007] The JEITA method is generally used to measure flicker in displays and other electronic devices. However, while this method can effectively measure simple light-emitting waveforms such as those of liquid crystals (LCDs), it is unsuitable for complex waveforms because the measured values ​​do not match visual observations.

[0008] Therefore, as a method for measuring the complexed emission waveform, there is the method specified in IEC standard "62341-6-3" in non-patent document 1.

[0009] For this standard, by convolving the acquired continuous stimulus values ​​with the TCSF (temporal contrast sensitivity function), which represents the eye's sensitivity to the emission frequency, a stimulus value that takes into account the eye's time response is derived, and a flicker index is derived based on this stimulus value.

[0010] The specific processing steps are as follows: (1) Continuously acquire the stimulus values ​​of the luminous display. (2) Perform Discrete Fourier Transform (DFT) processing on the acquired data to transform it into a spectrum. (3) Convolve the obtained spectrum with TCSF to superimpose the characteristics of the eye. (4) Perform Inverse Fourier Transform (iDFT) processing to generate the stimulus values ​​after TCSF superposition. (5) Calculate the (maximum value (Max) - minimum value (Min) / average value (Ave)) of the stimulus value data superimposed with TCSF to index the flicker intensity.

[0011] Non-patent document 1: IEC standard "62341-6-3"

[0012] However, the Digital Fourier Transform (DFT, iDFT) is an operation that assumes the input waveform is periodic and synchronized. Using this digital Fourier transform in scintillation measurement methods presents the following problems.

[0013] That is, for example, if the measurement time does not match (is not an integer multiple) the period of the emission waveform (e.g., during Vsync), the light intensity values ​​at the beginning and end of the obtained waveform will be inconsistent.

[0014] Such a waveform generates a large number of pseudo-frequency components that do not exist in the original waveform (=1 / measurement time×n, that is, the frequency and its harmonics with the measurement time as one period).

[0015] The superimposed waveform of this spectrum suffers from significant distortion at both the beginning and end, resulting in large errors in the flicker value and making it a measurement lacking reproducibility.

[0016] As a countermeasure, a method was proposed to remove the front-end and back-end of data acquisition to ensure synchronization. However, this method is not only cumbersome, but also may fail to acquire data of the desired measurement duration due to data deletion, resulting in poor convenience for flicker measurement. Furthermore, it cannot handle non-periodic emission waveforms, such as those of displays with the aforementioned VRR function.

[0017] Furthermore, as a countermeasure different from synchronization, a method using a window function to transform the data ends into the same value has been disclosed. In this method, the acquired waveform is first multiplied by the window function, the waveform is then superimposed with TCSF in the same way, and finally divided by the window function to produce the desired waveform. However, this method also has the problem that the error in waveform acquisition is amplified when dividing by the window function, resulting in a large error in the flicker value due to significant waveform distortion. Summary of the Invention

[0018] The present invention was made in view of the following technical background, and aims to provide an optical measurement device, optical measurement method, data processing device and program that can generate data as stimulus values ​​that take into account the time response of the eye and suppress waveform distortion, thereby enabling good flicker measurement and being able to handle measurement objects with non-periodic emission waveforms.

[0019] The above objectives are achieved through the following means.

[0020] (1) An optical measurement device, comprising:

[0021] The stimulus value acquisition unit receives light from the object being measured and continuously acquires the intensity equivalent to the stimulus value at constant time intervals.

[0022] The response characteristic acquisition unit acquires the aforementioned impulse response characteristics from a storage unit that stores impulse response characteristics equivalent to visual stimulus responses;

[0023] The digital filtering processing unit uses the impulse response characteristics obtained by the response characteristic acquisition unit to perform digital filtering processing on the continuous data of stimulus intensity obtained by the stimulus value acquisition unit, thereby generating data superimposed with the visual stimulus response.

[0024] (2) An optical measurement device, comprising:

[0025] The stimulus value acquisition unit receives light from the object being measured and continuously acquires the intensity equivalent to the stimulus value at constant time intervals.

[0026] The transformation unit converts the frequency characteristics of the eye stored in the storage unit into impulse response characteristics equivalent to the visual stimulus response; and

[0027] The digital filtering processing unit uses the impulse response characteristics transformed by the transformation unit to perform digital filtering processing on the continuous data of stimulus intensity obtained by the stimulus value acquisition unit, thereby generating data superimposed with the visual stimulus response.

[0028] (3) The optical measurement device according to item 2 above, wherein the frequency characteristics include phase characteristics.

[0029] (4) The optical measuring device according to any one of the preceding items 1 to 3, wherein the pulse response in the above-mentioned pulse response characteristics is 0.5 seconds or less.

[0030] (5) The optical measurement apparatus according to any one of the preceding items 1 to 3, wherein it comprises an export unit that exports a flicker index for a shorter time than the measurement time at multiple moments of the data generated by the digital filtering processing unit.

[0031] (6) The light measuring device according to any one of the preceding items 1 to 5, wherein the constant time interval when the stimulus value acquisition unit acquires the intensity corresponding to the stimulus value is a time interval of 6 kHz or less.

[0032] (7) The light measuring device according to any one of the preceding items 1 to 6, wherein the stimulus value acquisition unit acquires the intensity equivalent to the stimulus value by integration.

[0033] (8) The optical measurement device according to any one of the preceding items 1 to 6, wherein the above-mentioned impulse response characteristics exist in multiple ways.

[0034] (9) The optical measurement apparatus according to any one of the preceding items 1 to 8, wherein it is equipped with at least a Fourier transform unit and is also capable of performing scintillation measurement using the Fourier transform unit.

[0035] (10) A light measurement method, comprising:

[0036] The process involves receiving light from the object being measured and continuously acquiring stimulus values ​​at constant time intervals, with the intensity corresponding to the stimulus value.

[0037] The response characteristic acquisition step involves retrieving the impulse response characteristics from a storage unit that stores impulse response characteristics equivalent to visual stimulus responses; and

[0038] The continuous data of stimulus intensity obtained through the stimulus value acquisition step above are digitally filtered using the impulse response characteristics obtained through the response characteristic acquisition step above, thereby generating data superimposed with the visual stimulus response above.

[0039] (11) A light measurement method, comprising:

[0040] The process involves receiving light from the object being measured and continuously acquiring stimulus values ​​at constant time intervals, with the intensity corresponding to the stimulus value.

[0041] The transformation steps that convert the frequency characteristics of the eye stored in the storage unit into the impulse response characteristics equivalent to the visual stimulus response; and

[0042] The continuous data of stimulus intensity obtained through the stimulus value acquisition step are digitally filtered using the impulse response characteristics transformed by the above transformation steps to generate data superimposed with the above visual stimulus response.

[0043] (12) The optical measurement method according to item 10 or 11 above, wherein the pulse response in the above pulse response characteristics is less than 0.5 seconds.

[0044] (13) The optical measurement method according to any one of the preceding items 10 to 12, wherein it further includes a step of deriving a flicker index at multiple moments of the data generated by the above-described digital filtering process, in a time shorter than the measurement time.

[0045] (14) A data processing apparatus, comprising:

[0046] The receiving unit receives continuous data of stimulus intensity, which is obtained by receiving light from the object being measured and continuously acquiring intensity equivalent to the stimulus value at constant time intervals.

[0047] The response characteristic acquisition unit acquires the aforementioned impulse response characteristics from a storage unit that stores impulse response characteristics equivalent to visual stimulus responses; and

[0048] The digital filtering processing unit uses the impulse response characteristics obtained by the response characteristic acquisition unit to perform digital filtering processing on the continuous data of stimulus intensity received by the receiving unit, thereby generating data superimposed with the visual stimulus response.

[0049] (15) A data processing apparatus, comprising:

[0050] The receiving unit receives continuous data of stimulus intensity, which is obtained by receiving light from the object being measured and continuously acquiring intensity equivalent to the stimulus value at constant time intervals.

[0051] The transformation unit converts the frequency characteristics of the eye stored in the storage unit into impulse response characteristics equivalent to the visual stimulus response; and

[0052] The digital filtering processing unit performs digital filtering processing on the continuous data of stimulus intensity received by the receiving unit using the impulse response characteristics transformed by the above-mentioned transformation unit, and generates data superimposed with the above-mentioned visual stimulus response.

[0053] (16) The data processing apparatus according to item 14 or 15 above, wherein the pulse response in the above-mentioned pulse response characteristics is less than 0.5 seconds.

[0054] (17) The data processing apparatus according to items 14 to 16 above, wherein it includes an export unit that exports a flicker index for a shorter time than the measurement time at multiple moments of the data generated by the digital filtering processing unit.

[0055] (18) A program, wherein a computer is configured to perform the following steps:

[0056] The receiving step involves receiving continuous data of the intensity of a stimulus value obtained by receiving light from a measurement object and continuously acquiring the intensity equivalent to the stimulus value at constant time intervals.

[0057] The transformation receiving step converts the frequency characteristics of the eye stored in the storage unit into the impulse response characteristics equivalent to the visual stimulus response; and

[0058] The continuous data of stimulus intensity received in the above receiving step are digitally filtered using the impulse response characteristics transformed through the above transformation steps to generate data superimposed with the above visual stimulus response.

[0059] (19) A program, wherein a computer is configured to perform the following steps:

[0060] The receiving step involves receiving continuous data of the intensity of a stimulus value obtained by receiving light from a measurement object and continuously acquiring the intensity equivalent to the stimulus value at constant time intervals.

[0061] The transformation receiving step converts the frequency characteristics of the eye stored in the storage unit into the impulse response characteristics equivalent to the visual stimulus response; and

[0062] The continuous data of stimulus intensity received in the above receiving step are digitally filtered using the impulse response characteristics transformed through the above transformation steps to generate data superimposed with the above visual stimulus response.

[0063] (20) The procedure according to item 18 or 19 above, wherein the impulse response in the above impulse response characteristics is less than 0.5 seconds.

[0064] (21) The procedure according to any one of paragraphs 18 to 20 above, wherein the computer is further instructed to perform a step of deriving a flicker index at multiple moments of the data generated by the above digital filtering process, in a time period shorter than the measurement time length.

[0065] According to the invention described in items (1), (10), and (14) above, light from the object being measured is received, and the intensity corresponding to the stimulus value is continuously acquired at constant time intervals. The continuous data of the acquired stimulus value intensity is digitally filtered using the impulse response characteristics acquired from the storage unit to generate data superimposed with the visual stimulus response. Therefore, the generated data is stimulus value data that takes into account the eye's time response, and since no digital Fourier transform is performed, no waveform distortion is produced, thus enabling good flicker measurement based on this data. Furthermore, since it is not necessary to delete a portion of the waveform to remove distortion, it can also handle objects with non-periodic emission waveforms.

[0066] According to the invention described in items (2), (11), and (15) above, light from a measurement object is received, and the intensity corresponding to the stimulus value is continuously acquired at constant time intervals. The continuous data of the acquired stimulus value intensity is digitally filtered using the impulse response characteristics corresponding to the visual stimulus response, which are transformed from the frequency characteristics of the eye stored in the storage unit, to generate data superimposed with the visual stimulus response. Therefore, the generated data is stimulus value data that takes into account the time response of the eye, and since no digital Fourier transform is performed, no waveform distortion is generated, thus enabling good flicker measurement based on this data. Furthermore, since it is not necessary to delete a portion of the waveform to remove distortion, it is also possible to handle measurement objects with non-periodic emission waveforms.

[0067] According to the invention described in the preceding paragraph (3), since the frequency characteristics include phase characteristics, it is possible to reduce the error of the impulse response.

[0068] According to the invention described in the preceding items (4), (12) and (16), since the impulse response in the impulse response characteristic is less than 0.5 seconds, the invalid period of data during digital filtering processing can be reduced, and the measurement time can be shortened.

[0069] According to the invention described in the preceding items (5), (13) and (17), since a flicker index is derived at multiple moments of the data generated by digital filtering, in a time shorter than the measurement time, it is possible to measure the temporal variation of flicker intensity.

[0070] According to the invention described in the preceding paragraph (6), since the constant time interval for obtaining the intensity equivalent to the stimulus value is less than 6 kHz, high-precision measurement without waveform distortion can be performed by low-speed control.

[0071] According to the invention described in the preceding paragraph (7), since the intensity equivalent to the stimulus value is obtained by integration and the acquisition process is not performed at a high speed, the S / N ratio can be improved and high-precision measurement can be performed.

[0072] According to the invention described in the preceding paragraph (8), since there are multiple impulse response characteristics, it is possible to acquire data that matches the sensory characteristics.

[0073] According to the invention described in the preceding paragraph (9), conventional scintillation measurements using Fourier transform units can also be performed.

[0074] According to the invention described in the preceding item (18), a computer can perform the following processing: receiving continuous data of stimulus intensity obtained by receiving light from a measurement object and continuously acquiring intensity equivalent to the stimulus value at constant time intervals; acquiring impulse response characteristics from a storage unit storing impulse response characteristics equivalent to visual stimulus response; performing digital filtering processing on the received continuous data of stimulus intensity using the acquired impulse response characteristics; and generating data superimposed with visual stimulus response.

[0075] According to the invention described in the preceding item (19), a computer can perform the following processing: receiving continuous data of stimulus intensity obtained by receiving light from a measurement object and continuously acquiring intensity equivalent to the stimulus value at constant time intervals; transforming the frequency characteristics of the eye stored in the storage unit into impulse response characteristics equivalent to the visual stimulus response; and using the transformed impulse response characteristics to perform digital filtering processing on the received continuous data of stimulus intensity to generate data superimposed with the visual stimulus response.

[0076] According to the invention described in the preceding paragraph (20), a computer can perform the following processing: digital filtering processing is performed using the impulse response characteristics of less than 0.5 seconds.

[0077] According to the invention described in the preceding paragraph (21), a computer can be made to perform the following processing: at multiple moments of the data generated by the digital filtering process, a flicker index is derived for a time shorter than the measurement time. Attached Figure Description

[0078] Figure 1 This is a block diagram illustrating the functional structure of an optical measurement device according to one embodiment of the present invention.

[0079] Figure 2 This is a waveform diagram illustrating an example of the impulse response characteristics corresponding to a visual stimulus response.

[0080] Figure 3Figures (A) to (D) are used to illustrate the measurement results of the emission waveform after modeling the VRR display as the object of measurement.

[0081] Figure 4 (A) is a waveform diagram showing the data superimposed with stimulus values ​​obtained through digital filtering, and (B) is a graph showing the variation in flicker intensity.

[0082] Figure 5 This is a block diagram illustrating the functional structure of an optical measurement device according to other embodiments of the present invention.

[0083] Figure 6 (A) is a graph showing the sensitivity characteristics in the frequency characteristics of the eye, and (B) is a graph showing an example of the frequency characteristics of the eye including phase characteristics.

[0084] Explanation of reference numerals in the attached figures

[0085] 1...Optical measurement device; 2...Measuring head; 3...Data processing device; 20...Stimulus value acquisition unit; 21...Optical sensor; 22...Output unit; 31...Response storage unit; 32...Digital filtering processing unit; 33...Scintillation index derivation unit; 34...Frequency characteristic storage unit; 35...Transformation unit; 100...Measurement object Detailed Implementation

[0086] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0087] [First Implementation Method]

[0088] <Structure of the Optical Measurement Device>

[0089] Figure 1 This is a block diagram illustrating the functional structure of an optical measurement device 1 according to one embodiment of the present invention. Figure 1 As shown, the optical measurement device 1 includes a measurement head 2 and a data processing device 3. The measurement head 2 includes an optical sensor 21 and an output unit 22 for forming a stimulus value acquisition unit 20. The data processing device 3 is composed of a personal computer (PC) and includes a response storage unit 31, a digital filtering processing unit 32, and a flicker index output unit 33. Furthermore, Figure 1 Reference numeral 41 indicates the operation unit that operates the data processing device 3, and reference numeral 42 indicates the display unit that displays the digital filtering processing result of the digital filtering processing unit 32, the flicker index exported by the flicker index export unit 33, etc.

[0090] The light sensor 21 is a light-receiving sensor that receives light emitted from the object being measured, such as a display, 100. The stimulus value acquisition unit 20 has the following function: it continuously acquires the output of the light sensor 21 at constant time intervals through the output unit 22 and converts the output into continuous data of the stimulus value intensity.

[0091] The optical sensor 21 can be either a tristimulus value direct-reading type or a spectrophotometric type. The transformed stimulus values ​​may include, for example, tristimulus values ​​expressed as luminance, chromaticity (xy), and XYZ. In the continuous data transformation of stimulus values, filtering may be performed to remove noise. For example, a moving average processing using previous and subsequent data may be applied.

[0092] In this embodiment, the output unit 22 acquires data from the optical sensor 21 via integration. Integration improves measurement accuracy due to its superior signal-to-noise ratio (S / N). On the other hand, integration has the disadvantage of not being able to increase data acquisition speed as quickly as successive acquisition, but this is not a problem in this embodiment for the following reasons. Therefore, overall, integration is preferred over successive acquisition.

[0093] Furthermore, in this embodiment, the optical measurement device 1 is shown as consisting of a measurement head 2 and a data processing device 3, but it can also be an optical measurement device 1 with an independent structure that includes both the measurement head 2 and the data processing device 3 within the same machine.

[0094] <Is high-speed sampling required?>

[0095] The eye's frequency response (TCSF) has almost no sensitivity in the high-frequency region. Therefore, even if the emission waveform of the object 100 is measured to be high-speed and high-frequency, it is not necessary to obtain a high speed of the emission waveform (shape) faithfully in scintillation measurement.

[0096] Considering the workload in the computational processes described later, it is preferable to have fewer data points, and the data acquisition speed does not need to be faster than required. Furthermore, unnecessarily high speeds can lead to a decrease in incident light and an increase in circuit noise, thus degrading the signal-to-noise ratio (S / N) and impairing measurement accuracy.

[0097] The following illustrates an example of data acquisition speed. In recent years, high-speed control displays such as Vsync240Hz have been released. When driven by PWM, high-speed data acquisition of at least 24kHz (100 data points per cycle) is required to acquire the waveform (shape). Furthermore, for the older Vsync60Hz displays, high-speed data acquisition of at least 6kHz is required. However, from the above perspective, even below 6kHz is perfectly adequate and suitable for flicker measurement.

[0098] In this embodiment, data is acquired at 1.5 kHz based on the above. Furthermore, the data acquisition speed can be varied depending on the object being measured 100, the driving conditions, etc. For example, it becomes low speed when the driving condition is amplitude modulation drive, and high speed when the driving condition is PWM modulation drive.

[0099] In successive data acquisition methods, when data is acquired at a high speed of over 6kHz, it can be directly processed, or it can be extracted or averaged to reduce the amount of data to be processed.

[0100] <Response storage unit regarding the characteristics of stored impulses>

[0101] The data processing device 3 includes a response storage unit 31, which stores impulse response characteristics equivalent to visual stimulus response.

[0102] Figure 2 This illustrates an example of the impulse response characteristics corresponding to a visual stimulus response. The stored response period only needs to allow enough time for the eye's response (reaction) to converge. The eye's response typically converges after about 0.5 seconds.

[0103] The visual stimulus response, as a sensory characteristic, depends considerably on the individual, the environment, and the object being measured 100. Therefore, multiple impulse response characteristics can be stored in the response storage unit 31, allowing for flexible use of these characteristics depending on the conditions. Alternatively, the system can be configured such that the user can store (register) impulse response characteristics in the response storage unit 31.

[0104] Examples of parameters upon which the visual stimulus response depends include the measurement area, brightness, color, gender, age, ambient brightness, and individual characteristics of the stimulus value acquisition unit 20. The selection of impulse response characteristics can be done manually by the user or automatically by the light measurement device 1. For example, when color is used flexibly as a parameter, automatic selection can be achieved using the stimulus value acquired for flicker measurement. As another example, a sensor can be installed in the light measurement device 1 to automatically switch between these parameters.

[0105] Furthermore, the response storage unit 31 may not be built into the data processing device 3, or it may exist externally. In this case, the pulse response data can be obtained from the external response storage unit 31 and processed.

[0106] <About Digital Filtering>

[0107] The digital filtering process of the digital filtering processing unit 32 is executed by the processor, such as the CPU, which is provided in the data processing device 3, according to the operation program stored in ROM or the like and loaded into RAM.

[0108] The digital filtering processing unit 32 receives continuous data of stimulus intensity acquired by the stimulus value acquisition unit 20, and acquires impulse response characteristics from the response characteristic storage unit 31. It uses the acquired impulse response characteristics to perform digital filtering processing on the received continuous data of stimulus intensity to generate data superimposed with visual stimulus response (hereinafter also referred to as superimposed stimulus value data).

[0109] To perform digital filtering, at least the amount of stimulus value data corresponding to the impulse response period is required. Furthermore, the leading edge of the generated superimposed stimulus value data is the period preceding the response period, which is invalid due to missing data. To reduce this missing data period, in this embodiment, the impulse response period is set to less than 0.5 seconds of eye response convergence. Digital filtering is performed using this less than 0.5-second response amount.

[0110] The timing of digital filtering is not limited. It can be done after acquiring continuous stimulus values, or even if all data has not been acquired, the acquired stimulus values ​​can be processed sequentially.

[0111] <Generation of Overlay Stimulus Value Data and Export of Scintillation Indicators>

[0112] As described above, the digital filtering processing unit 32 generates and outputs data superimposed with the visual stimulus response. The flicker index derivation unit 33 uses this superimposed stimulus value data to derive a flicker index. The flicker index derivation processing of the flicker index derivation unit 33 is also executed by the processor of the data processing device 3 according to the action program.

[0113] The following example illustrates the export of the blinking indicator.

[0114] When the emission waveform is a periodic waveform and the flicker intensity is static, it is preferable to derive (maximum value (Max) - minimum value (Min) / average value (Ave)) for the entire time range of the superimposed stimulus value data and set it as the index value. More preferably, if the time range of the derived index value can be set to the condition for obtaining synchronization, i.e., an integer multiple of the emission period, the measurement error will be reduced. In addition, as a method for obtaining synchronization, there are methods such as using an external synchronization signal and using a user-input synchronization frequency, but it is not limited to these methods.

[0115] On the other hand, Vsync frequencies in VRR displays sometimes switch randomly. For example, in mobile devices, there are devices that use a low-speed drive for still image displays to save power, but drive at 60Hz for dynamic image displays and touch screens. Therefore, when flicker intensity varies, it is preferable to generate a time-varying variation in flicker intensity.

[0116] Specifically, for the superimposed stimulus value data, (Max-Min) / Ave is derived with a constant time width at each time step to generate the temporal variation of the index value. Using this time variation data, it is easy to observe the extent to which the flicker intensity varies under what conditions. Furthermore, the time width is preferably an integer multiple of the Vynsc period.

[0117] exist Figure 3 The figure shows the measurement results of the emission waveform after modeling the VRR display as the measurement object 100. Figure 3 (A) represents continuous data on stimulus intensity acquired by the display. The display's drive frequency varies from 60Hz to 24Hz to 60Hz. There is no grayscale change. The frequency of the continuous stimulus intensity data varies according to the drive frequency.

[0118] Figure 3 (B) is a magnified view of the timing around the time when the drive frequency changes from 60Hz to 24Hz. Figure 3 (C) is a magnified diagram showing the timing around the time when the drive frequency changes from 24Hz to 60Hz.

[0119] Figure 3 (D) is a waveform of the impulse response used for digital filtering. The impulse response period is less than 0.5 seconds.

[0120] Figure 4 (A) is the superimposed stimulus value data obtained through digital filtering. Obviously, no waveform distortion was produced.

[0121] Figure 4 (B) is a graph showing the variation in flicker intensity. The flicker index values ​​were derived at a time set to 12 Hz.

[0122] Furthermore, the method for deriving flicker indicators is not limited to the above methods; other methods can also be used, such as methods derived by area ratio (e.g., the Flicker Index based on the IES method).

[0123] Thus, in this embodiment, the intensity corresponding to the stimulus value is continuously acquired at constant time intervals. The continuous data of the acquired stimulus value intensity is digitally filtered using the impulse response characteristics acquired from the response storage unit 31 to generate data superimposed with the visual stimulus response. Therefore, the generated superimposed stimulus value data takes into account the stimulus value of the eye's time response, and since no digital Fourier transform is performed, no waveform distortion occurs. Therefore, good flicker measurement can be performed based on this superimposed stimulus value data. Furthermore, since it is not necessary to delete a portion of the waveform to remove distortion, it is also possible to handle the measurement object 100 with a non-periodic emission waveform.

[0124] [Second Implementation]

[0125] In this embodiment, the impulse response is determined using the TCSF method.

[0126] <Structure of the Optical Measurement Device>

[0127] Figure 5 This is a block diagram illustrating the functional structure of the optical measurement device 1 according to the second embodiment of the present invention. Figure 5 As shown, the light measurement device 1 includes a stimulus value acquisition unit 20, a frequency characteristic storage unit 34, a transformation unit 35, a digital filtering processing unit 32, and a flicker index derivation unit 33.

[0128] The stimulus value acquisition unit 20 has the same structure as the stimulus value acquisition unit 20 in the first embodiment, and has the following function: continuously acquires the output of the light sensor 21 at constant time intervals through the output unit 22, and converts the output into continuous data of stimulus value intensity.

[0129] The characteristics of the eye have been extensively studied, and numerous TCSF reports have been published regarding its time response. For example, the differences for each brightness level are described in the literature "De Lange, H. Journal of the Optical Society of America, 1958 48, 777-785".

[0130] In order to utilize these research findings, in this embodiment, the frequency characteristics of the eye, such as TCSF, are stored in the frequency characteristic storage unit 34. The transformation unit 35 transforms the frequency characteristics into impulse response characteristics equivalent to visual stimulus response by performing an inverse Fourier transform on the frequency characteristics.

[0131] The TCSF used in IEC standards and other technologies described in previous works only represents the frequency characteristics of the eye. Figure 6 Sensitivity data as shown in (A). However, in order to ensure the correct conversion to impulse response characteristics, it is preferable to include phase data in the frequency characteristics. Therefore, in this embodiment, the frequency characteristics including phase characteristics are stored in the frequency characteristic storage unit 34.

[0132] exist Figure 6 Example (B) shows an example of the frequency characteristics of an eye that includes phase characteristics. Similar to the first embodiment, multiple frequency characteristics of the eyes can be stored in the frequency characteristic storage unit 34, allowing for flexible use of the frequency characteristics depending on the conditions. Alternatively, the configuration can be such that the user can store (register) the frequency characteristics of the eyes in the frequency characteristic storage unit 34, or automatically select any frequency characteristic.

[0133] The digital filtering processing unit 32 performs digital filtering processing on the continuous data of stimulus intensity acquired by the stimulus value acquisition unit 20 using the impulse response characteristics transformed from the frequency characteristics of the eye by the transformation unit 35, and generates superimposed stimulus value data. Except that the impulse response characteristics are generated by the transformation unit 35, it operates in the same way as the digital filtering processing unit 33 in the first embodiment.

[0134] Furthermore, the time data of the impulse response characteristics generated by the transformation unit 35 is often sufficiently long compared to the eye's response period (around 0.5 seconds). For example, when the frequency characteristics are stored at 0.1 Hz intervals, the impulse response characteristics data generated by the inverse Fourier transform is 10 seconds.

[0135] In digital filtering, as described in the first embodiment, the impulse response period is directly linked to the length of the invalid period of the superimposed stimulus value data. Therefore, in this embodiment, it is preferable to suppress the invalid period and use only the first 0.5 seconds or less of the transformed impulse response characteristic for digital filtering.

[0136] The flicker index derivation unit 33, like in the first embodiment, derives flicker index values ​​based on superimposed stimulus value data.

[0137] Figure 5 The light measurement device 1 shown receives measurement commands from a personal computer (PC) 5 and sends the measurement results to the PC. The measurement results are superimposed stimulus value data and flicker index values.

[0138] Alternatively, it can also be structured as follows, i.e. Figure 5 The frequency characteristic storage unit 34, the transformation unit 35, the digital filtering processing unit 32, and the flicker index exporting unit 33 in the optical measurement device 1 of the second embodiment shown are provided in the PC5, which is a data processing device, in the same way as in the first embodiment. The processor in the PC5 performs operations according to the operation program to perform the transformation processing of the eye's frequency characteristics to impulse response, the generation of superimposed stimulus value data based on digital filtering processing, and the exporting of flicker index values.

[0139] Or, you can Figure 5 The optical measurement device 1 shown retains its original structure and includes a frequency characteristic storage unit 34, a conversion unit 35, a digital filtering processing unit 32, and a flicker index derivation unit 33 within the PC5.

[0140] Alternatively, the frequency characteristic storage unit 34 may not be built into the optical measurement device 1, or it may exist externally. In this case, the frequency characteristics can be obtained from the external frequency characteristic storage unit 34 and processed.

[0141] [Third Implementation Method]

[0142] It can also be in Figure 1 The optical measurement device 1 involved in the first embodiment shown, Figure 5 The optical measurement apparatus 1 according to the second embodiment shown is equipped with the function of performing TCSF convolution based on the conventional method specified in IEC standard "62341-6-3". In the case of this conventional measurement method, in order to perform TCSF convolution operation in frequency space, discrete Fourier transform (DFT) processing and inverse Fourier transform (iDFT) processing are required. Therefore, in order to also have the functions of the conventional method, the optical measurement apparatus 1 of the first embodiment requires a discrete Fourier transform (DFT) unit and an inverse Fourier transform (iDFT) unit. In the case of the second embodiment, since the inverse Fourier transform (iDFT) can be performed by the transform unit 35, a discrete Fourier transform (DFT) unit is required.

[0143] Furthermore, conventional measurement methods do not require switching from the measurement method of this embodiment, and simultaneous measurement can be achieved by sharing the data acquired by the stimulus value acquisition unit 20.

[0144] However, since conventional measurement methods have the advantage of not generating invalid periods, they can shorten the measurement time while ensuring measurement accuracy when simultaneously measuring periodic emission waveforms, which is beneficial. On the other hand, the measurement method of this embodiment, as described above, can achieve flicker measurement with a high degree of freedom in terms of measurement conditions and emission waveform. By incorporating both measurement methods, it can be used flexibly according to the purpose, increasing convenience.

Claims

1. An optical measurement device, wherein, have: The stimulus value acquisition unit receives light from the object being measured and continuously acquires the intensity equivalent to the stimulus value at constant time intervals. The response characteristic acquisition unit acquires the aforementioned impulse response characteristics from a storage unit that stores impulse response characteristics equivalent to visual stimulus responses; as well as The digital filtering processing unit uses the impulse response characteristics obtained by the response characteristic acquisition unit to perform digital filtering processing on the continuous data of stimulus intensity obtained by the stimulus value acquisition unit, thereby generating data superimposed with the visual stimulus response.

2. An optical measurement device, wherein, have: The stimulus value acquisition unit receives light from the object being measured and continuously acquires the intensity equivalent to the stimulus value at constant time intervals. The transformation unit converts the frequency characteristics of the eye stored in the storage unit into impulse response characteristics equivalent to visual stimulus response; as well as The digital filtering processing unit uses the impulse response characteristics transformed by the transformation unit to perform digital filtering processing on the continuous data of stimulus intensity obtained by the stimulus value acquisition unit, thereby generating data superimposed with the visual stimulus response.

3. The optical measurement device according to claim 2, wherein, The frequency characteristics described above include phase characteristics.

4. The optical measurement apparatus according to any one of claims 1 to 3, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

5. The optical measurement apparatus according to any one of claims 1 to 3, wherein, have: The export unit generates the time variation of the flicker index value based on the data generated by the aforementioned digital filtering processing unit.

6. The optical measurement apparatus according to any one of claims 1 to 3, wherein, The constant time interval for the stimulus value acquisition unit to acquire the intensity equivalent to the stimulus value is a time interval of less than 6 kHz.

7. The optical measurement apparatus according to any one of claims 1 to 3, wherein, The aforementioned stimulus value acquisition unit obtains the intensity equivalent to the stimulus value through integration.

8. The optical measurement apparatus according to any one of claims 1 to 3, wherein, There are multiple impulse response characteristics mentioned above.

9. The optical measurement device according to claim 6, wherein, There are multiple impulse response characteristics mentioned above.

10. The optical measurement device according to claim 7, wherein, There are multiple impulse response characteristics mentioned above.

11. A method for measuring light, wherein, Include: The process involves receiving light from the object being measured and continuously acquiring stimulus values ​​at constant time intervals, with the intensity corresponding to the stimulus value. The response characteristic acquisition step is to obtain the above-mentioned impulse response characteristics from the storage unit that stores the impulse response characteristics equivalent to the visual stimulus response; as well as The continuous data of stimulus intensity obtained through the stimulus value acquisition step above are digitally filtered using the impulse response characteristics obtained through the response characteristic acquisition step above, thereby generating data superimposed with the visual stimulus response above.

12. A method for measuring light, wherein, Include: The process involves receiving light from the object being measured and continuously acquiring stimulus values ​​at constant time intervals, with the intensity corresponding to the stimulus value. The transformation step that converts the frequency characteristics of the eye stored in the storage unit into the impulse response characteristics equivalent to the visual stimulus response; as well as The continuous data of stimulus intensity obtained through the stimulus value acquisition step are digitally filtered using the impulse response characteristics transformed by the above transformation steps to generate data superimposed with the above visual stimulus response.

13. The optical measurement method according to claim 11, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

14. The optical measurement method according to claim 12, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

15. The light measurement method according to any one of claims 11 to 14, wherein, Also includes: Based on the data generated through the above digital filtering process, a step is taken to derive the time variation of the flicker index value.

16. A data processing apparatus, wherein, have: The receiving unit receives continuous data of stimulus intensity, which is obtained by receiving light from the object being measured and continuously acquiring intensity equivalent to the stimulus value at constant time intervals. The response characteristic acquisition unit acquires the aforementioned impulse response characteristics from a storage unit that stores impulse response characteristics equivalent to visual stimulus responses; as well as The digital filtering processing unit uses the impulse response characteristics obtained by the response characteristic acquisition unit to perform digital filtering processing on the continuous data of stimulus intensity received by the receiving unit, thereby generating data superimposed with the visual stimulus response.

17. A data processing apparatus, wherein, have: The receiving unit receives continuous data of stimulus intensity, which is obtained by receiving light from the object being measured and continuously acquiring intensity equivalent to the stimulus value at constant time intervals. The transformation unit converts the frequency characteristics of the eye stored in the storage unit into impulse response characteristics equivalent to visual stimulus response; as well as The digital filtering processing unit performs digital filtering processing on the continuous data of stimulus intensity received by the receiving unit using the impulse response characteristics transformed by the above-mentioned transformation unit, and generates data superimposed with the above-mentioned visual stimulus response.

18. The data processing apparatus according to claim 16, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

19. The data processing apparatus according to claim 17, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

20. The data processing apparatus according to claims 16-19, wherein, have: The export unit generates the time variation of the flicker index value based on the data generated by the aforementioned digital filtering processing unit.

21. A computer-readable recording medium, wherein, It stores programs for causing the computer to perform the following steps: The receiving step involves receiving continuous data of the intensity of a stimulus value obtained by receiving light from a measurement object and continuously acquiring the intensity equivalent to the stimulus value at constant time intervals. The response characteristic acquisition step is to obtain the above-mentioned impulse response characteristics from the storage unit that stores the impulse response characteristics equivalent to the visual stimulus response; as well as The continuous data of stimulus intensity received in the above receiving step are digitally filtered using the impulse response characteristics obtained through the above response characteristic acquisition step, thereby generating data superimposed with the above visual stimulus response.

22. A computer-readable recording medium, wherein, It stores programs for causing the computer to perform the following steps: The receiving step involves receiving continuous data of the intensity of a stimulus value obtained by receiving light from a measurement object and continuously acquiring the intensity equivalent to the stimulus value at constant time intervals. The transformation receiving step converts the frequency characteristics of the eye stored in the storage unit into the impulse response characteristics equivalent to the visual stimulus response; as well as The continuous data of stimulus intensity received in the above receiving step are digitally filtered using the impulse response characteristics transformed through the above transformation steps to generate data superimposed with the above visual stimulus response.

23. The computer-readable recording medium according to claim 21, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

24. The computer-readable recording medium according to claim 22, wherein, The impulse response in the above impulse response characteristics is less than 0.5 seconds.

25. The computer-readable recording medium according to any one of claims 21 to 24, wherein, The above procedure also causes the above computer to perform: Based on the data generated through the above digital filtering process, a step is taken to derive the time variation of the flicker index value.

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