Vehicle Camera Color Mask Red Transparent Pixels

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Solution Overview

Problem

Existing automatic switching systems for vehicle headlights face challenges in distinguishing between low and high beams due to the size of light sources being mapped to one sensor pixel, leading to reduced spatial resolution and difficulty in differentiating red and white light sources, especially under movement.

Innovation Solution

A color mask with only two types of filter pixels, red and transparent, offset in rows and columns, allowing for high spatial resolution detection of low and high beams without the need for interpolation, reducing resolution loss to approximately 1.5 times that of a monochrome sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a standard Bayer pattern mask with multiple color filters is used, then complete color differentiation is achieved, but spatial resolution is reduced by a factor of 2

Engineering Contradiction:
Improvecolor differentiation precisionVSAvoidspatial resolution
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent extracts only the essential color information needed for headlight detection (red vs. non-red) by using just two filter types instead of the full RGB Bayer pattern. This extraction approach removes unnecessary color channels while preserving the critical differentiation capability between red tail lights and white headlights.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different filter properties to different spatial locations in a structured pattern. By arranging red and transparent filters in alternating rows and offset columns, each region of the sensor receives appropriately filtered light for its specific detection task, optimizing both color differentiation and spatial resolution locally.

Inventive Principle:
Principle #3Local quality

2Device complexity

If light sources are mapped to single sensor pixels, then the detection process is simplified, but differentiation between red and white light sources becomes difficult

Engineering Contradiction:
Improvedetection process complexityVSAvoidlight source color differentiation
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the sensor array into regions with different filter characteristics (red-filtered rows and transparent-filtered rows). This segmentation allows simultaneous capture of color-specific and intensity-specific information from the same light source, enabling differentiation even when the light source maps to a single pixel or small region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a spectral dimension to the detection by incorporating red-sensitive filters alongside transparent filters. This creates an additional measurement dimension (red vs. non-red) that works alongside the spatial and intensity dimensions, enabling color differentiation without requiring multiple pixels per light source.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If vehicle movement is present, then dynamic scene capture is enabled, but reliable color differentiation becomes more difficult

Engineering Contradiction:
Improvedynamic scene capture capabilityVSAvoidcolor differentiation reliability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent prepares for motion-induced variations by pre-arranging offset patterns of red and transparent filters that remain effective regardless of the direction or amount of motion. The offset column arrangement ensures that even with pitching or yawing movements, sufficient filtered and unfiltered pixel data is captured for reliable color differentiation.

Inventive Principle:
Principle #10Preliminary action

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 solution enables reliable detection of pitching and yaw movements, improving the differentiation of red light sources from white reflections, enhancing safety by maintaining high spatial resolution and reducing the complexity of the detection process.

Implementation Method 1

a color mask with only two different filter pixels, red and transparent, offset in relation to one another in the rows and/or columns of the matrix arrangement

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

the first filter pixels have a red transmission behavior and the second filter pixels have a broader transmission behavior that includes the red spectral range and other spectral ranges

Methodology Applied
Scientific EffectSelective light absorption: Absorption (EM radiation)

Implementation Method 3

A filter pixel or filter segment is referred to as a transparent filter pixel, which allows light to pass over a larger wavelength range and thus appears essentially transparent or white in the optical range; it thus permits a luminescence signal in which the overall brightness is measured

Methodology Applied
Scientific EffectBroadband light transmission:

Data Source

PatentEP2191654B1Color mask for an image sensor of a vehicle camera
Publication Date: 2014.12.03 ROBERT BOSCH GMBH
  • EP2191654B1 patent drawingFigure 1~2
  • EP2191654B1 patent drawingFigure 3~4

AI summary

The invention relates to a color mask for an image sensor (7) of a vehicle camera (2), comprising a matrix arrangement (mij) of first filter pixels (R) and second filter pixels (C). In each horizontal line (I1) and/or each vertical column (kj), first filter pixels (R) and second filter pixels (C) are arranged, wherein the first filter pixels (R) and second filter pixels (C) exhibit different transmission behaviors for optical light. Advantageously, the second filter pixels (C) exhibit more extensive transmission behavior, wherein they may be transparent particularly for optical light. The first filter pixels (R) are preferably red. Reliable detection of a light source is achieved with only low resolution reduction compared to an image sensor without color mask; when used in a vehicle, particularly reliable detection can be achieved during pitching or yawing movements of the vehicle. Furthermore, the invention relates to a camera for a vehicle comprising said color mask and to a vehicle having said camera.