Photodetector In-Plane Delay Skew Correction
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Solution Overview
Problem
Existing light receiving apparatuses face challenges in accurately correcting in-plane delay skew, which leads to processing delays and affects applications requiring immediate responses, especially in distance measurement systems like automatic driving operations.
Innovation Solution
The implementation of a correction processing system that calculates and applies correction values based on the distance from each pixel to the time measuring section, using histogram correction and linear interpolation to shift histograms in the time axis direction, thereby reducing processing delays and improving response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If buffers for delay adjustment are added to wiring in paths from light receiving elements to the time-to-digital converter, then in-plane delay skew is eliminated, but variation in characteristics among the added buffers deteriorates the in-plane delay skew correction
Solution Approach 1:
The patent replaces the physical buffer circuit approach with a software-based correction method implemented in the application processor. Instead of adding hardware buffers to adjust delay physically, the system acquires depth map data and performs digital correction of in-plane delay skew through signal processing algorithms, eliminating the reliability issues associated with buffer characteristic variations.
Solution Approach 2:
The patent introduces the application processor as an intermediary component that mediates between the light receiving apparatus and the final depth map output. The application processor receives depth map data, performs in-plane delay skew correction through software processing, and generates corrected depth map data, thereby separating the correction function from the hardware wiring path.
2Measurement precision
If the application processor is used to correct the in-plane delay skew, then correction processing can be performed, but processing delay occurs in units of frames which adversely affects applications requiring immediate responses
Solution Approach 1:
The patent implements in-plane delay skew correction as part of the depth map acquisition process itself, rather than as a subsequent frame-based processing step. The correction is performed on individual pixel data as it is being acquired and processed, allowing real-time correction without waiting for complete frame accumulation. This preliminary action approach enables immediate response applications while maintaining correction accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high-speed correction of in-plane delay skew, reducing processing delays significantly and allowing for accurate distance measurements in real-time applications such as automatic driving and distance measurement for moving subjects.
Implementation Method 1
elements generating signals in response to reception of photons
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A light receiving apparatus of the present disclosure includes a light receiving section with a plurality of pixels arranged in a two-dimensional shape, a signal line connected to each of the pixels, a time measuring section connected to the signal line and measuring a time from a light emission instruction timing to a light reception timing, a histogram creating section creating a histogram of a measured value measured by the time measuring section, a storage section storing correction values corresponding to positions of the pixels in the light receiving section, a correction processing section executing correction processing on the histogram created by the histogram creating section, on the basis of the correction values stored in the storage section, and an output section outputting a signal subjected to the correction processing by the correction processing section. A distance measuring apparatus of the present disclosure uses the light receiving apparatus configured as described above.