Region-of-Interest Filter for Dual-Sensor Observation
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Solution Overview
Problem
Existing imaging systems struggle to clearly display both the details of a scene and a light spot formed by a laser beam across a wide range of illumination conditions, often requiring impractical dual display setups or amplification devices that introduce artifacts or damage sensors.
Innovation Solution
An observation device with overlapping fields from a first and second image sensor, connected to an electronic image processing circuit and a laser transmitter, uses a region-of-interest filter to block or attenuate luminous flux, allowing for the superimposition of images to visualize both the light spot and scene details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image sensor is used to capture the entire scene, then the device complexity is reduced, but the ability to visualize both the bright laser spot and scene details simultaneously deteriorates
Solution Approach 1:
The field of view of the second image sensor is divided into three distinct regions by the region-of-interest filter: a first region with near-total light blocking, a second region with spectral filtering, and a third region with maximum light transmission. This segmentation allows each region to capture different information (laser spot, reduced background, and scene details) that can be combined to solve the visualization problem.
Solution Approach 2:
Different regions of the filter apply different optical properties to different parts of the image sensor's field of view. The first region provides near-total blocking for laser spot detection, the second region provides spectral filtering for reduced background, and the third region provides maximum transmission for scene details. This local differentiation of optical properties enables simultaneous capture of both bright spot and scene details.
2Illumination intensity
If photodiode amplification devices are used to enhance the laser spot visibility, then the spot becomes more distinguishable, but harmful effects such as blooming artifacts and sensor damage increase
Solution Approach 1:
The filter segments the light paths by creating three distinct regions: the first region with near-total blocking isolates the laser spot detection from overwhelming background light, eliminating the need for photodiode amplification and its associated harmful effects while still enabling spot visualization.
Solution Approach 2:
The patent converts the harmful effect of bright background light into a benefit by using the first region's near-total blocking to eliminate background interference, allowing the laser spot to be detected without requiring amplification that would cause blooming or sensor damage.
3Illumination intensity
If the integration time is increased to capture scene details in dim lighting, then the scene details become more visible, but the laser spot becomes overexposed and loses detail
Solution Approach 1:
The filter segments the light paths so that the first region captures primarily the laser spot with minimal background, the second region provides spectral filtering, and the third region captures scene details. This allows the second image sensor to use a longer integration time for scene details while the first region's near-total blocking prevents the laser spot from becoming overexposed.
Solution Approach 2:
Different regions of the filter apply different optical properties: the first region's near-total blocking protects the laser spot measurement from overexposure during long integration times, while the third region's maximum transmission ensures scene details are captured with sufficient light during the same integration period.
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
Enables clear visualization of both the light spot and scene details across varying illumination conditions without artifacts, ensuring precise spatial calibration and effective image merging.
Implementation Method 1
The filter is configured to ensure, in the second region, a near-total blocking of light from the scene, in the first region, an attenuation of light outside the predetermined wavelength range
Implementation Method 2
The optronic sensor, most often of the CMOS or CCD type, has light-sensitive elements arranged contiguously to form an array. These elements are designed to collect the light reflected or emitted by a portion of the scene
Implementation Method 3
a laser emitter to emit in a predetermined area of the field of the second sensor a laser beam in a predetermined range of wavelengths
Data Source
Figure 1~2
AI summary
Device for observation and designation, comprising a first image sensor and a second image sensor which are connected to an electronic image-processing circuit connected to a display, the first image sensor and the second image sensor being designed to have superimposing fields which respectively output at least a first image and a second image of a same scene, and the device comprising a laser emitter for emitting, in a predetermined area of the field of the second sensor, a laser beam in a predetermined range of wavelengths; a filter with regions of interest extending in front of the second sensor in order to provide an attenuation of the light flux outside the predetermined range of wavelengths in a first region, a substantially total blocking of the light flux coming from the scene in a second region and a maximum transmission of the light flux in a third region; the electronic processing circuit being designed to superimpose the two images by using the area of the second image corresponding to the third region of the filter to spatially calibrate the second image with respect to the first image. Method for observation and designation using such filtering.