Flicker Threshold Measurement Using Fixed Refresh Rate Displays
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Solution Overview
Problem
The flicker value examination method for measuring mental fatigue is hindered by the large size and complexity of its measurement devices, and the limited refresh rates of general display devices, such as computers and mobile phones, restrict the ability to control light-blinking cycles, making it difficult to perform flicker value examinations effectively.
Innovation Solution
A measurement device and method that utilize a display with a specific refresh rate, where the arithmetic processing unit changes the timing, number of OFF periods, size, contrast, or color of the image to determine the flicker threshold by detecting when a test subject starts or stops perceiving flicker, allowing for the evaluation of mental fatigue using widely available devices like computers and mobile phones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flicker value examination devices are used, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent applies universality by enabling general-purpose display devices (computers, mobile phones) to perform flicker threshold measurements that were previously exclusive to specialized medical equipment. The system uses existing display refresh mechanisms and built-in cameras to achieve professional-grade measurements without requiring dedicated hardware, thus reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent uses copying by capturing display output through the device's own camera or another camera to create an optical copy of the flickering stimulus. This copied visual signal is then analyzed to determine flicker threshold, eliminating the need for complex specialized display hardware while preserving measurement accuracy.
2Device complexity
If general display devices with limited refresh rates are used, then device complexity is reduced, but the ability to control light-blinking cycles is restricted
Solution Approach 1:
The patent applies dynamics by adapting the measurement methodology to work with the fixed refresh rates of general display devices. Instead of requiring variable frequency control, the system dynamically adjusts measurement parameters and uses multiple refresh rate measurements to calculate flicker threshold, thereby maintaining versatility despite hardware limitations.
Solution Approach 2:
The patent uses parameter changes by measuring flicker perception at multiple display refresh rates (e.g., 60Hz, 120Hz, 240Hz) and using these varying parameters to calculate the flicker threshold. This approach transforms the limitation of fixed refresh rates into a measurement advantage, allowing the system to determine threshold through comparative analysis across different refresh parameters.
3Measurement precision
If specialized LED apparatuses are used for flicker examination, then measurement precision is improved, but ease of operation and accessibility worsen
Solution Approach 1:
The patent applies self-service by enabling devices to perform their own flicker threshold measurements using their inherent display and sensing capabilities. A smartphone can display the stimulus and capture the response through its own camera, eliminating the need for separate specialized equipment and complex setup procedures, thus greatly improving ease of operation while maintaining precision.
Data Source
AI summary
This invention relates to a flicker threshold measurement device including: an arithmetic processing unit 1; a display unit 8 with a fixed refresh rate; and an operation unit 9, wherein: the arithmetic processing unit 1 displays an image on the display unit 8 in an ON/OFF manner; the arithmetic processing unit 1 changes the display timing by monotonously increasing or decreasing the number of OFF periods per second; the arithmetic processing unit 1 monotonously increases or decreases at least one of: the number of OFF pixels in the image, the size of the image, and the contrast of the OFF pixels, during a period in which the display timing is not changed; each of the OFF periods is a reciprocal of the refresh rate; and the arithmetic processing unit 1 determines the number of OFF periods when a test subject 10 operates the operation unit 9 as he/she starts or stops perceiving flicker, as information corresponding to a flicker threshold. The present measurement device is capable of measuring a flicker threshold in a wide range of conditions, using a display apparatus with a fixed refresh rate (vertical synchronization frequency). Thereby, the present measurement device is useful for evaluating fatigue.