Projection Lens Rotation Correction for OSD and External Images
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Solution Overview
Problem
Existing projection apparatuses do not adequately address rotation correction for images when the projection lens is rotated by angles other than 180°, particularly for images rotated by 90° or 270°, and do not provide rotation correction for On-Screen Display (OSD) images.
Innovation Solution
A projection apparatus with a rotatable projection lens, a detection unit to monitor the lens's rotation state, and a control unit that performs rotation correction on images based on the detected rotation, distinguishing between images from external devices and OSD images to ensure appropriate correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rotation correction is applied to all images when the projection lens rotates, then OSD images maintain correct orientation, but external device images may become incorrectly rotated
Solution Approach 1:
The patent segments the image processing into two distinct paths: one for OSD images that applies rotation correction, and another for external device images that does not apply rotation correction. This segmentation allows the system to handle different image types with appropriate processing, resolving the contradiction between maintaining OSD orientation accuracy and preserving external device image compatibility.
Solution Approach 2:
The patent applies rotation correction selectively based on image type rather than uniformly to all images. By identifying OSD images through specific processing paths and applying correction only to those images, the system achieves local quality optimization where correction is needed (OSD) while avoiding unnecessary correction that would harm other image types (external devices).
2Adaptability or versatility
If rotation correction is not applied to external device images, then image compatibility is maintained, but OSD images will appear rotated on the projection surface
Solution Approach 1:
The patent implements separate processing paths that segment OSD image handling from external device image handling. The OSD processing path includes rotation correction while the external device path maintains original orientation, allowing each type to be optimized independently for its specific requirements.
Solution Approach 2:
The patent introduces an intermediary mechanism (the control unit with image type identification capability) that determines whether rotation correction should be applied. This intermediary selectively routes images through appropriate processing paths based on their type, enabling compatibility for external devices while ensuring correct orientation for OSD images.
Data Source
AI summary
A projection apparatus capable of, when an image input from an external device and an OSD image are rotated by rotation of a projection lens, performing rotation correction suitable for the respective images is provided. A projection apparatus (1) includes a housing; a projection lens (3) that has a holder and that is rotatably attached to the housing; a first rotation position detection unit (70A) and a second rotation position detection unit (70B) that detect rotation states of the holder; a DMD (22B) that outputs, to the projection lens (3), a composite image of a projection image output from an external device and an OSD image including a character output from an internal memory; and a control unit that performs rotation correction on the OSD image and that does not perform rotation correction on the projection image based on detection results of the first rotation position detection unit (70A) and the second rotation position detection unit (70B) when the holder of the projection lens (3) rotates.