Camera Shutter Lag Measurement via Display Pattern Switching

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Solution Overview

Problem

Existing methods for measuring shutter time lag and display delay in cameras face challenges in achieving high accuracy due to limitations in LED turn-on time and identifying display elements in captured images, especially when the turn-on time is short, leading to difficulties in specifying display patterns and deducing shutter time lag.

Innovation Solution

A method involving a display pattern with multiple display elements that switch between two states, where the pattern continuation time is adjusted to ensure the display elements are easily identifiable in the captured image, allowing for precise measurement of shutter time lag by synchronizing the camera's shutter operation with the display pattern switching operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the LED turn-on time is reduced to increase measurement resolution, then the measurement precision of shutter time lag is improved, but the display elements become difficult to identify in captured images

Engineering Contradiction:
Improveshutter time lag measurement precisionVSAvoiddifficulty of identifying display elements
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies parameter changes by adjusting the pattern continuation time parameter to an optimal value that balances measurement resolution with detectability. Specifically, the pattern continuation time is set to be sufficiently long to ensure display elements are clearly identifiable in captured images, while still allowing for high-resolution shutter time lag measurement through the sequential switching of multiple display elements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the measurement process into multiple discrete display patterns, where each pattern continues for a sufficient duration to be clearly captured. By dividing the measurement into sequential patterns with adequate continuation time, the system achieves high measurement resolution without sacrificing the identifiability of individual display elements in each captured image.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the pattern continuation time is shortened to increase measurement resolution, then the measurement precision is improved, but the display elements may not be clearly identifiable in the captured image

Engineering Contradiction:
Improveshutter time lag measurement precisionVSAvoidreliability of display element identification
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent optimizes the pattern continuation time parameter to a specific value range that ensures reliable display element identification. By carefully selecting this parameter, the system maintains high measurement precision while guaranteeing that display elements remain clearly identifiable and reliably detectable in captured images.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent dynamically adjusts the pattern continuation time based on the specific measurement requirements and camera characteristics. This dynamic optimization ensures that each display pattern continues long enough to be reliably captured and identified, while still enabling high-resolution shutter time lag measurement through the overall sequential switching process.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple display elements switch sequentially at short time intervals, then the measurement resolution is increased, but the contrast between display states becomes insufficient for reliable identification

Engineering Contradiction:
Improvemeasurement resolutionVSAvoidcontrast between display states
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent optimizes the pattern continuation time parameter to ensure sufficient contrast between display states. By setting this parameter appropriately, each display element maintains its state long enough to achieve adequate brightness contrast in captured images, enabling reliable identification while still allowing for high-resolution measurement through sequential switching of multiple elements.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the accuracy of shutter time lag measurement by ensuring display elements are clearly identifiable, even at shorter pattern continuation times, facilitating precise determination of shutter time lag and display delay.

Implementation Method 1

a first display state in which the display element emits light and a second display state in which the display element does not emit light

Methodology Applied
Scientific EffectLight emitting diode: Light Emitting Diode

Data Source

PatentEP2908173B1Method for measuring shutter time LAG and method for manufacturing a camera
Publication Date: 2020.04.15 SEIKO EPSON CORP
  • EP2908173B1 patent drawingFigure 1~1B
  • EP2908173B1 patent drawingFigure 2~2B
  • EP2908173B1 patent drawingFigure 3~3B

AI summary

A shutter time lag of a camera is easily measured. j display elements are brought into a first display state, and the remaining display elements are brought into a second display state observed as being darker than the first display state, and thereby an m-th display pattern is formed by display elements of a display unit. After a predetermined time has elapsed, k display elements are brought into the second display state among j display elements in the first display state, and k display elements are brought into the first display state among the remaining display elements in the second display state, and thereby switching the display elements of the display unit in an (m + 1)-th display pattern is executed. A camera captures an image of the display unit executing the switching operation, in response to a shutter operation of the camera performed in synchronization with the switching operation. The shutter time lag is deduced from the image captured by the camera.