Image Sensor Signal Delay Compensation for 3D Depth Accuracy
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Solution Overview
Problem
Image sensors used in 3D capturing devices experience depth errors due to signal delays caused by the structural limitations of the driver placement, leading to inaccuracies in depth information acquisition.
Innovation Solution
An image sensor and image processing device that includes a pixel array, a reference clock circuit, and a time-to-analog convert circuit to measure and correct signal delays, generating compensation data to accurately calculate Time of Flight (TOF) and correct depth values in depth images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the driver is disposed on one side or both sides of the pixel array within the image sensor, then the device complexity is reduced, but signal delay occurs causing depth error
Solution Approach 1:
The patent applies preliminary action by measuring the signal delay in advance through pixel clock signals generated at different pixels, then using this pre-measured delay information to correct depth values before final depth image generation. This resolves the contradiction by maintaining the simple driver placement while compensating for its harmful delay effect through preliminary measurement and correction.
2Area of stationary object
If the driving signal travels far from the driver, then the coverage area of the driver is improved, but delay occurs causing change in charge ratio
Solution Approach 1:
The patent implements feedback by using pixel clock signals generated at each pixel to provide delay information back to the processing system. This feedback mechanism allows the system to recognize and correct the delay effects that occur when driving signals travel long distances, thereby maintaining charge ratio accuracy while preserving wide driver coverage.
3Productivity
If delay of driving signal is not corrected, then the processing speed is maintained, but depth error occurs in depth image
Solution Approach 1:
The patent replaces complex mechanical or hardware-based delay compensation methods with a signal processing approach. By substituting the need for complex physical delay correction mechanisms with digital processing of pixel clock signals and depth value correction, the system achieves accurate depth measurement without sacrificing processing speed.
Data Source
AI summary
An image sensor includes a pixel array configured to receive a driving signal, sense a light signal reflected from an object in response to the driving signal, and generate pixel clock signals indicating delay of the driving signal; a reference clock circuit configured to generate a reference clock signal; and a time-to-analog convert circuit configured to convert delay times between the pixel clock signals and the reference clock signal into analog values.