Imaging Apparatus Sensor Tilt for Diagonal Surveillance Focus
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Solution Overview
Problem
Surveillance cameras with diagonally oriented optical axes face challenges in maintaining focus across a range of depths, especially under low illuminance, due to shallow depth of field, making it difficult to adjust focus manually and maintain focus on subjects like human faces.
Innovation Solution
An imaging apparatus with a focus controller, relative tilt angle controller, and acquisition unit that calculates and adjusts the relative tilt angle based on the installation angle and distance to a standard surface, allowing for automatic focus adjustment at desired heights, even when the subject is not directly in the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the diaphragm is fully opened for imaging under low illuminance, then the brightness of the captured image is improved, but the depth of field becomes shallow and focus is lost
Solution Approach 1:
The patent applies dynamics by making the image sensor tilt angle adjustable rather than fixed. The tilt angle is dynamically changed based on the desired focus distance, allowing the system to adapt between different depth of field requirements while maintaining the fully opened diaphragm state for optimal brightness.
Solution Approach 2:
The patent changes the geometric parameter of the image sensor tilt angle to control the focus plane orientation. By adjusting this angle parameter, the system achieves different focus distances and depth of field ranges without changing the diaphragm aperture, thus maintaining image brightness while achieving proper focus.
2Manufacturing precision
If manual adjustment of relative tilt angle and focus position is performed, then focus can be achieved at specific heights, but the adjustment process is complex and time-consuming
Solution Approach 1:
The patent implements self-service by enabling the system to automatically calculate and adjust the image sensor tilt angle based on user-input parameters such as subject height and distance. The control unit performs the computation and adjustment without requiring manual intervention, making the system adjust itself according to the imaging requirements.
Solution Approach 2:
The patent applies preliminary action by pre-calculating the optimal tilt angle using the Scheimpflug principle before actual imaging begins. The system computes the required angle based on known parameters (subject height, distance, optical characteristics) and positions the sensor accordingly, eliminating the need for trial-and-error manual adjustment during installation.
3Area of stationary object
If the optical axis is oriented diagonally downward for surveillance, then the coverage area is improved, but the focus surface does not match the subject surface
Solution Approach 1:
The patent applies asymmetry by intentionally tilting the image sensor at an asymmetric angle relative to the optical axis. This asymmetric configuration allows the focus plane to be aligned with the ground or subject surface while the optical axis maintains its downward diagonal orientation for wide surveillance coverage.
Solution Approach 2:
The patent introduces an additional degree of freedom by tilting the image sensor in the vertical dimension. This dimensional change allows the focus plane to be independently oriented to match the subject surface (e.g., ground level) while the optical axis remains positioned for optimal surveillance coverage area.
Data Source
AI summary
An imaging apparatus includes: a focus controller configured to adjust focus by driving a lens; a relative tilt angle controller configured to incline a focus surface by controlling a relative tilt angle of the lens to an image sensor; and an acquisition unit configured to acquire an installation angle of the imaging apparatus based on a relative tilt angle and a distance from a standard surface on the focus surface inclined in accordance with the standard surface. The acquisition unit acquires a relative tilt angle when the focus surface is inclined in accordance with a height of a subject based on the installation angle and a distance between the standard surface and height information of the subject, and outputs the relative ti It angle to the relative tilt angle controller.