Projection Device Ghost Compensation via Phase Modulation
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Solution Overview
Problem
Existing projection devices using phase-modulating spatial light modulation elements suffer from ghost images that are difficult to remove, especially when projecting images at a distance, and require mechanical mechanisms for ghost removal, which add complexity.
Innovation Solution
A projection device and method that incorporates a light source, spatial light modulation element, and control means to display a phase distribution including a ghost compensation image, where the ghost image portion is made dark and the desired image portion is bright, making the ghost image difficult to visually recognize.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a phase-modulating spatial light modulation element is used for projection, then image projection capability is improved, but ghost images appear that reduce image quality
Solution Approach 1:
The invention applies preliminary anti-action by displaying a ghost compensation image that has already been processed to counteract the ghost effect. The compensation image is generated in advance with inverted phase information that will cancel out the ghost when combined with the original image during projection, preventing the ghost from being visually recognized without requiring mechanical adjustments during projection.
Solution Approach 2:
The invention changes the brightness parameter of the ghost image portion in the compensation image to a low level, making the ghost difficult to visually recognize. By adjusting the brightness parameter of specific regions in the compensation image (making ghost portions dark and desired image portions bright), the system reduces ghost visibility while maintaining projection capability.
2Object-affected harmful factors
If mechanical mechanisms are added to remove ghosts, then ghost image visibility is reduced, but device complexity increases
Solution Approach 1:
The invention replaces mechanical ghost removal mechanisms with an optical compensation approach. Instead of using mechanical devices to physically remove or block ghosts, the system uses image processing to generate a compensation image that optically counteracts the ghost effect through phase modulation, thereby eliminating the need for complex mechanical mechanisms.
Solution Approach 2:
The invention creates a compensation image that is a processed copy of the original image, with specific modifications (inverted phase, adjusted brightness) that will cancel out the ghost when combined during projection. This copying approach allows ghost removal through image data manipulation rather than mechanical intervention.
3Object-affected harmful factors
If ghost compensation image with high brightness is displayed totally, then ghost visibility is reduced, but desired image brightness is compromised
Solution Approach 1:
The invention applies local quality by setting different brightness levels for different portions of the compensation image. Specifically, the ghost image portion is set to low brightness (dark) while the desired image portion is set to high brightness (bright). This localized brightness adjustment allows the system to reduce ghost visibility in specific regions without compromising the overall brightness and quality of the desired projected image.
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
The solution effectively reduces the visibility of ghost images in projection devices, eliminating the need for mechanical ghost removal mechanisms and improving image quality by setting the ghost image portion to a low brightness level.
Implementation Method 1
a phase distribution of an image to be projected onto a projection surface to be displayed on the display part
Implementation Method 2
light from the light source to be reflected by the display part
Data Source
AI summary
In order to make a ghost image appearing when projection light is projected using a phase-modulating spatial light modulation element difficult to visually recognize, a projection device includes a light source, a light-source driving means, a spatial light modulation element, a modulation element control means, a projection control means, and a projection optical system, wherein the projection control means controls the light-source driving means and the modulation element control means in such a way as to cause a phase distribution of an image including a ghost compensation image and a desired image to be displayed on a display part, the ghost compensation image being an image for which high brightness is set totally and in which a display information portion to be displayed on a projection surface is bright while a ghost image portion that appears in association with the display information is dark.