Dual Light Modulation for Luminance Correction
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Solution Overview
Problem
Existing image projection technologies face challenges in maintaining tone property and contrast due to uneven brightness on three-dimensional objects caused by reflectance differences, and conventional edge blending methods compromise contrast and tone quality when correcting luminance.
Innovation Solution
An image projection apparatus utilizing two light modulation elements, where one element forms a luminance correcting image based on luminance correction data irrelevant to the input image signal, and the other forms the main image, allowing for superimposition to correct luminance and maintain tone and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If electric luminance correction is applied to lower luminance in high-reflectance areas, then uneven brightness is corrected, but the number of tones is reduced and tone property deteriorates
Solution Approach 1:
The projection system is divided into multiple projectors, each projecting a portion of the overall image. By segmenting the projection task, each projector can apply luminance correction only to its own image data without affecting the global tone distribution, thereby maintaining tone property while correcting local brightness unevenness
Solution Approach 2:
Luminance correction is applied locally to each projector's image data based on the specific reflectance characteristics of the projection surface areas it covers. This allows targeted correction of brightness unevenness in high-reflectance areas without globally reducing the number of tones, thus preserving overall tone property
2Illumination intensity
If electric luminance correction is applied to peripheral parts for edge blending, then connected parts become inconspicuous, but the contrast of the projection image lowers
Solution Approach 1:
The image is divided into multiple projection areas covered by different projectors. Edge blending is performed by segmenting the correction application to only affect peripheral regions where projectors overlap, while preserving the contrast of central image areas through selective correction based on spatial position
Solution Approach 2:
Luminance correction for edge blending is applied locally to peripheral parts of each projector's image data, with the correction strength varying by position. This localized approach makes connected parts inconspicuous while maintaining the contrast of the overall projection image by avoiding global luminance reduction
3Illumination intensity
If a light shield or filter is used to correct uneven brightness, then luminance correction is achieved, but positioning accuracy must be high and versatility is reduced
Solution Approach 1:
The mechanical light shield or filter system is replaced with an electronic image processing approach. By substituting physical correction elements with digital luminance correction applied to image data, the system eliminates the need for high positioning accuracy and gains versatility to adapt to different projection surfaces and content types
Solution Approach 2:
Instead of physically changing the light shield shape or filter transmittance, the system changes luminance parameters through electronic correction of image data. This allows flexible adaptation to different reflectance characteristics of projection surfaces without requiring physical reconfiguration, thereby improving versatility
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 configuration ensures the original tone property and contrast are preserved while providing versatile luminance correction, reducing the conspicuousness of luminance lifts in edge blending and correcting uneven brightness caused by reflectance differences on three-dimensional objects.
Implementation Method 1
a first light modulation element (7) configured to modulate light from a light source (1)
Implementation Method 2
a second light modulation element (10) configured to modulate light from the first light modulation element (7)
Implementation Method 3
an optical system (8, 9) configured to guide a projection image in which an image formed by the light modulated by the first light modulation element (7) and an image formed by the light modulated by the second light modulation element (10) are superimposed on each other
Data Source
AI summary
An image projection apparatus includes an image signal inputter configured to input an image signal, a first light modulation element configured to modulate light from a light source, a second light modulation element configured to modulate light from the first light modulation element, an optical system configured to guide a projection image in which an image formed by the light modulated by the first light modulation element and an image formed by the light modulated by the second light modulation element are superimposed on each other to a projection optical system, a first driver configured to drive one of the first and second light modulation elements based on the image signal, and a second driver configured to drive the other of the first and second light modulation elements based on a luminance correction data irrelevant to the image signal.