Projection Focusing Motor Positioning via Ranging and Traversal
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Solution Overview
Problem
Existing projection focusing methods, such as camera-based and ranging-based solutions, suffer from high time consumption, low speed, instability, and lack of accuracy in achieving focus.
Innovation Solution
A projection focusing method that determines the focusing direction based on the comparison of two projection distance values and converts the target motor position into a target motor position range with a preset motor position error, allowing the motor to move within a defined range to achieve optimal focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based projection contrast focusing technology is used, then focusing can be achieved by utilizing pixel difference values, but time consumption is high and focusing speed is low
Solution Approach 1:
The patent applies preliminary action by using the ranging component to obtain the projection distance before the focusing process. This preliminary distance information is used to calculate a target motor position, which serves as a starting point or reference for the subsequent focusing traversal. By performing this preliminary measurement and calculation, the system avoids starting the focusing process from an arbitrary position, thereby reducing the number of steps required to reach the optimal focus point and significantly decreasing focusing time while maintaining precision.
2Speed
If ranging-based focusing solution is used, then focusing speed may be improved, but stability and accuracy are insufficient
Solution Approach 1:
The patent merges two different focusing approaches: the ranging-based method (which provides speed) and the camera-based contrast method (which provides stability and precision). The system uses the ranging component to quickly obtain distance information and calculate a target position, then uses the camera to traverse a limited range around this target position to find the optimal focus point by evaluating pixel difference values. This combination allows the system to benefit from both the speed of ranging and the precision of image analysis, achieving both high focusing speed and high reliability.
3Measurement precision
If sequential traversal of multiple positions is performed from initial position, then focusing can be achieved, but time consumption is high
Solution Approach 1:
The patent performs preliminary action by calculating a target motor position based on the projection distance obtained from the ranging component before the actual focusing traversal begins. This target position serves as a smart starting point that is already close to the optimal focus position, rather than starting from an arbitrary initial position. The system then only needs to traverse a limited range around this pre-calculated target position, significantly reducing the number of steps required compared to sequential traversal from any random starting point, thereby improving focusing efficiency while maintaining accuracy.
4Measurement precision
If motor position error range is considered, then focusing precision can be maintained, but search range increases
Solution Approach 1:
The patent applies local quality by concentrating the focusing search effort in a specific local range around the pre-calculated target motor position, rather than searching the entire possible motor position range. The system determines a focused motor position range centered on the target position (with boundaries at target position plus/minus motor position error). This localized search approach ensures that the motor only moves through the necessary small range to account for positioning errors, maintaining focusing precision while minimizing the actual movement distance and time required.
Data Source
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AI summary
The disclosure relates to the technical field of projection auto-focusing, and embodiments particularly disclose a projection focusing method, a projection focusing apparatus, a projector, and a readable storage medium. According to the projection focusing method provided by this application, an initial position of a focused motor is roughly determined based on a current projection distance, a focusing direction is determined according to the current projection distance and a projection distance corresponding to the current motor position, a position of a clearest projection picture can be found by traversing a few motor positions, and the speed and precision of projection focusing are greatly increased.