Automotive Lighting Image Compression for CAN Bandwidth Limits
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Solution Overview
Problem
Current automotive lighting systems face challenges in managing large amounts of data from multiple light sources, particularly when dealing with moving images, due to bandwidth limitations in the CAN protocol, and struggle with compressing non-linear light functionalities like welcome and goodbye lights.
Innovation Solution
A method for managing image data in automotive lighting devices involves compressing data by selecting relevant portions of pixel values, approximating non-zero values, and transforming matrices into unidimensional arrays, reducing data size while maintaining the base structure of the light pattern, and decompressing this data within the light module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the CAN protocol bandwidth is limited to reduce data transmission load, then energy consumption and network load are reduced, but data transmission speed and image projection speed deteriorate
Solution Approach 1:
The image data is segmented into multiple packets for transmission over the CAN bus. Each packet contains a portion of the image data along with control information, allowing the large data volume to be transmitted in manageable chunks that fit within the limited bandwidth while maintaining acceptable transmission speed
Solution Approach 2:
The patent transforms the two-dimensional image data matrix into a one-dimensional data stream for transmission. This dimensional transformation allows the data to be packaged and transmitted efficiently over the serial CAN bus protocol, converting spatial data structure into a temporal transmission sequence that optimizes bandwidth utilization
2Adaptability or versatility
If the number of light sources is increased to provide adaptive lighting functionalities, then lighting performance and functionality are improved, but data management complexity and bandwidth requirements worsen
Solution Approach 1:
The patent combines control information for multiple light sources into a single integrated image data structure. Instead of managing each light source separately, all pixel data for the entire light module is packaged together in one transmission frame, reducing the number of individual data management operations and simplifying the control architecture
Solution Approach 2:
The image data structure is designed to be universal and adaptable, capable of representing various lighting patterns and functionalities through the same data format. This allows the system to handle different lighting scenarios (ambient lighting, welcome lights, warning lights) using a single unified data management approach, reducing complexity
3Quantity of substance
If image data is compressed to reduce data size, then bandwidth requirements and transmission time are reduced, but image quality and precision deteriorate
Solution Approach 1:
The patent applies partial compression by only reducing the precision of pixel intensity values when necessary. Instead of fully compressing all data, the system maintains full precision for critical image regions while applying compression only where visual quality is less sensitive, achieving a balance between data size reduction and image quality preservation
Solution Approach 2:
The patent changes the precision parameter of pixel intensity values from high precision (e.g., 8-bit or 16-bit) to lower precision (e.g., 4-bit or 6-bit) representation. This parameter change reduces the data size significantly while the human visual system's limited sensitivity to subtle intensity differences means the perceived image quality remains acceptable for automotive lighting applications
4Productivity
If data transmission bandwidth is increased to improve image projection speed, then image projection speed is improved, but energy consumption and network load worsen
Solution Approach 1:
The patent performs preliminary data preparation and packaging at the source (control unit) before transmission. Image data is pre-processed, segmented, and formatted into optimized transmission packets that maximize bandwidth efficiency. This preliminary action reduces the total transmission time and allows the use of lower bandwidth CAN bus configurations, thereby reducing energy consumption while maintaining acceptable projection speeds
Data Source
AI summary
A method for managing an image in an automotive lighting device. The method includes providing a first image pattern including a plurality of pixels, selecting a relevant portion of the value of each pixel and preparing compressed data related to the relevant values, together with data related to the position of the pixel with a value equal to zero.