Pulsed Lamp Bit-Depth Extension via Light Modulation
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Solution Overview
Problem
The bit-depth of spatial light modulator-based video display systems is limited by the mechanical limitations of the modulator's elements, leading to restricted color and brightness resolution, and existing techniques like dithering introduce noticeable temporal artifacts.
Innovation Solution
A system and method that reduces the light output from a pulsed lamp and applies lower significance bits during reduced light periods, synchronizing with a lower master clock speed to increase bit-depth without introducing unwanted artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dithering techniques are used to increase effective bit-depth, then the number of perceivable colors increases, but temporal dither noise becomes noticeable in the images
Solution Approach 1:
The patent applies periodic pulse width modulation to the light source, creating regular intervals of reduced light output. During these periodic low-light intervals, least significant bits are displayed without introducing temporal dither noise, as the periodic nature allows the human visual system to adapt and not perceive the artifacts
Solution Approach 2:
The patent changes the light output parameter of the illumination source, reducing it to a low-light level during specific time intervals. This parameter change enables the display of additional bit information during periods when the human eye is less sensitive to brightness changes, thereby increasing effective bit-depth without noticeable artifacts
2Measurement precision
If the bit-depth is increased beyond the minimum LSB transition time limitation, then greater color detail is achieved, but the mechanical limitations of the modulator elements prevent further increase
Solution Approach 1:
The patent introduces the light source as an intermediary element between the data signal and the spatial light modulator. By controlling the light output of this intermediary, the system can extend the effective bit-depth beyond what the mechanical elements alone could achieve, as the light intensity modulation adds an additional degree of freedom for encoding bit information
Solution Approach 2:
The patent adds a temporal dimension to the bit display process by utilizing time-varying light intensity. Instead of relying solely on the spatial modulation capabilities of the modulator elements, the system incorporates temporal modulation of light output, effectively adding another dimension for encoding additional bit information
Data Source
AI summary
In accordance with the teachings of the present invention, a system and method for increasing the bit-depth of a video display system using a pulse lamp are provided. In one embodiment, the method includes illuminating a digital micro-mirror device with a light source having a variable power supply, receiving a signal indicating the light output provided to the digital micro-mirror device by the light source should be reduced to a target level during a predetermined time period, reducing a power supplied to the light source by the variable power supply in response to the signal such that the light output of the light source is reduced to about a target level during the predetermined time period, displaying a least significant bit on the digital micro-mirror device during the predetermined time period, and decreasing a speed of a master clock controlling the digital micro-mirror device in response to the light output of the light source deviating below the target level during the predetermined time period.