Helmet Display Pulse Modulation for False Contouring
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Solution Overview
Problem
Dynamic false contouring occurs in head or helmet-mounted digital display systems due to rapid relative movement of the eye and the image display surface, causing perceived false additions and subtractions of light pulses between adjacent pixels, leading to image artifacts like bright flashes or sparkling effects.
Innovation Solution
A method and system that control the digital display device to generate a predetermined sequence of light pulses with reduced longest pulse duration, using a set of pulse weightings where the greatest weighting is less than half the total duration for maximum brightness, replacing conventional binary-weighted pulses with binary and non-binary weighted pulses of shorter durations to minimize false contouring effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binary-weighted pulse modulation is used to generate pixel brightness levels, then the display can achieve sufficient brightness levels with fewer pulses, but dynamic false contouring artifacts occur due to long pulse durations causing false addition and subtraction of light between adjacent pixels
Solution Approach 1:
The patent changes the pulse duration parameters by using a maximum pulse duration that is less than half of what would be required in a conventional binary-weighted scheme. This parameter change reduces the temporal spread of light pulses, thereby minimizing false addition and subtraction effects that cause dynamic false contouring artifacts while maintaining adequate brightness level representation through a modified pulse weighting system
2Object-generated harmful factors
If the maximum pulse duration is reduced to less than half of the total illumination duration, then dynamic false contouring is reduced, but more pulses are required to achieve the same number of brightness levels
Solution Approach 1:
The patent segments the pulse modulation scheme into multiple shorter pulses with different weightings. Instead of using a few long pulses as in binary-weighted modulation, the system divides the illumination duration into multiple segments (pulses) with weightings that are less than half of the maximum conventional pulse duration. This segmentation allows for adequate brightness representation while reducing the harmful temporal spread that causes dynamic false contouring
Solution Approach 2:
The patent employs a dynamic pulse weighting system where the relative durations of multiple pulses are adjusted to achieve the desired brightness levels. The system dynamically selects and combines pulses with different weightings (where the greatest weighting is less than half of conventional maximum) to represent various brightness levels, providing flexibility in managing pulse complexity while reducing false contouring effects
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
Significantly reduces the effect of dynamic false contouring, improving the perceived image quality by reducing false additions and subtractions of pulses between pixels, thereby enhancing the display's brightness level accuracy and reducing artifacts.
Implementation Method 1
each of the pixels in an image to be viewed is generated using a pulse modulation technique whereby the perceived brightness and colour of a pixel is determined by the total amount of light of a given wavelength that is emitted by the display device in respect of that pixel during an 'image refresh period'
Data Source
AI summary
A method for controlling a digital display device of a head or helmet-mounted display system and a head or helmet-mounted digital display system implementing the method are provided with the aim of controlling the display device in such a way as to reduce the effect of dynamic false contouring on the quality of a displayed image. According to the method, received image data defining brightness levels according to a scheme of light pulse modulation based upon binary-weighted pulse durations are converted into a data defining a sequence of pulses of binary and non-binary weighted duration in which the highest value weighting represents a pulse of a duration less than half the total duration of illumination required during an image refresh period to achieve a pixel at the highest brightness level. In a further embodiment, the weighting of highest value represents a pulse of duration less than one quarter of the duration required for highest pixel brightness.