Ultra Short Throw Projector Brightness Correction via Reflector Sensors
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Solution Overview
Problem
Projection image quality is deteriorated due to nonuniform brightness caused by limitations in the craftsmanship and assembly tolerances of optical lenses in ultra short throw projection systems, leading to unwanted contrasts between image regions on the screen.
Innovation Solution
A projection apparatus with a reflector partitioned into sub-regions, each equipped with brightness sensors, acquires real-time brightness values of sub-images and adjusts them using a brightness adjusting value to ensure uniform brightness across the image, overcoming innate defects in the projection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical lenses with limited craftsmanship and assembly tolerances are used in ultra short throw projection systems, then the device complexity is reduced and ease of manufacture is improved, but brightness uniformity deteriorates leading to unwanted contrasts between image regions
Solution Approach 1:
The projection system divides the image into multiple sub-images corresponding to different regions (e.g., center and edge regions). Brightness sensors are separately arranged for each sub-image region to independently detect brightness values. This segmentation allows targeted brightness correction for each region without requiring perfect optical uniformity, resolving the contradiction between ease of manufacture and brightness uniformity.
Solution Approach 2:
The system adjusts the brightness parameter of individual sub-images based on detected values. By changing brightness parameters through digital processing after detection, the system compensates for optical imperfections without requiring precise manufacturing, thus maintaining ease of manufacture while achieving brightness uniformity.
2Measurement precision
If multiple brightness sensors are arranged on the reflector to detect sub-image brightness values, then measurement precision of brightness distribution is improved, but device complexity increases
Solution Approach 1:
The reflector serves multiple functions: it reflects light to form the image and simultaneously acts as a mounting platform for brightness sensors. This multi-functionality allows the sensors to be integrated into the existing optical structure without adding separate complex support systems, achieving precise brightness measurement while minimizing device complexity.
Solution Approach 2:
The projection system uses its own reflected light path to provide illumination for the brightness sensors. The sensors detect brightness by receiving the same light that forms the image, eliminating the need for separate test light sources or additional illumination systems. This self-service approach enables precise measurement without increasing device complexity.
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 achieves uniform and even brightness among sub-images, significantly improving the projection image quality by compensating for brightness distortions caused by hardware defects in the projection system.
Implementation Method 1
the reflector is configured to reflect the light beam transmitted from the optic set onto the screen
Implementation Method 2
each of the brightness sensors are configured to acquire a respective brightness value of a respective sub-image
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present disclosure provides a projection image correcting method and a projection apparatus. The method includes: receiving real-time brightness values of M sub-images in a current to-be-displayed image, the real-time brightness values being acquired by a plurality of sensors arranged on a reflector which is located opposite to a projection lens, and obtaining a brightness adjusting value of a j-th sub-image in the current to-be-displayed image according to the real-time brightness values of the M sub-images. Adjustment is made, in combination with brightness adjusting values obtained from the current image to be displayed, to brightness values of each sub-image in an image to be displayed after the current to-be-displayed image, thereby making brightness of displayed images uniform, and improving the projection image quality.