CMOS Image Sensor Lens Control via ISP Signal Synthesis
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Solution Overview
Problem
CMOS image sensors output digital signals without a separate video signal or on-screen display (OSD) information, making it difficult to control video lenses directly, as existing technologies rely on these signals for lens control.
Innovation Solution
An image capture device is designed with a receiver to process digital signals from a CMOS image sensor, generating sync signals, converting luminance signals into direct current (DC) level mode, and synthesizing these signals to create a lens control signal, allowing for iris control of the video lens without a separate terminal for video signals or OSD information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a CMOS image sensor is used, then the device can output digital signals, but the video lens cannot be controlled directly because there is no separate video signal terminal without gain and OSD information
Solution Approach 1:
The patent introduces an intermediary signal processing path within the ISP that extracts luminance information from the digital signal and converts it into a format suitable for lens control. This intermediary conversion process enables lens control without requiring a separate video signal terminal, resolving the contradiction by adding functional capability through internal signal transformation rather than external hardware additions.
Solution Approach 2:
The patent changes the parameter representation of the luminance signal from its original digital format to a DC level mode signal that can directly control the lens. By transforming the signal parameters (converting PWM mode to DC level mode with variable amplitude), the system enables direct lens control while maintaining the digital signal output capability of the CMOS sensor.
2Ease of operation
If a separate terminal for video signal without gain and OSD information is provided, then the video lens can be controlled, but the device structure becomes more complex
Solution Approach 1:
The patent makes the existing digital signal output serve multiple functions: it continues to provide image data while simultaneously enabling lens control through the extracted luminance information. By making the digital signal terminal multi-functional, the system eliminates the need for a separate control terminal while maintaining ease of operation, thus resolving the contradiction between operational simplicity and structural complexity.
3Manufacturing precision
If the luminance signal is converted from PWM mode to DC level mode, then the lens control precision is improved, but the signal processing time increases
Solution Approach 1:
The patent performs the luminance signal extraction and DC level conversion in advance during the normal image signal processing pipeline, rather than as a separate post-processing step. By incorporating this conversion into the existing processing flow and preparing the control signal in advance, the system minimizes additional processing time while maintaining high lens control precision.
Data Source
AI summary
Provided is a method for controlling a video lens in an image capture device which uses a complementary metal oxide semiconductor (CMOS) image sensor. A vertical sync (Vsync) signal and a horizontal sync (Hsync) signal are separately generated and then synthesized. Thereafter, the resulting signal is synthesized with a DC level mode luminance signal to generate a lens control signal for controlling the video lens.