Gated Camera Noise Reduction via Line Segmentation
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Solution Overview
Problem
The existing gated camera systems face issues such as noise in horizontal stripes affecting image quality, long generation times for slice images, and extended sensing times due to sequential light emission and exposure for multiple ranges.
Innovation Solution
The proposed gated camera system divides the depth direction into multiple ranges, using an illumination device, image sensor, controller, and image processing device to generate slice images. This involves radiating probe light, controlling light emission and exposure timings, and processing sensor images to reduce noise and optimize image generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If noise reduction processing is performed on sensor images, then image quality is improved, but processing time increases
Solution Approach 1:
The image processing device segments the sensor image into multiple lines and processes each line independently by selecting M pixel values in ascending order, calculating their average, and subtracting it from each pixel value in that line. This segmented line-by-line processing reduces the overall computational burden compared to processing the entire image at once, thereby improving image quality while controlling processing time.
Solution Approach 2:
The patent applies partial action by selectively processing only the necessary pixel values (M smallest values per line) rather than all pixel values. This partial processing approach is sufficient to remove horizontal stripe noise while avoiding the excessive computation that would result from processing every pixel, thus balancing image quality improvement with acceptable processing time.
2Loss of time
If resolution of sensor image is reduced for closer ranges, then transmission time is shortened, but image quality for close objects deteriorates
Solution Approach 1:
The patent applies local quality by transmitting full-resolution sensor images only for farther ranges where objects appear smaller and lower resolution is acceptable, while transmitting reduced-resolution images for closer ranges. This localized adaptation of image quality to range-specific requirements optimizes transmission time without unnecessarily compromising image quality where high resolution is not critical.
Solution Approach 2:
The system dynamically changes the resolution parameter of transmitted sensor images based on the range distance. For closer ranges, the resolution parameter is reduced to shorten transmission time, while for farther ranges, full resolution is maintained. This parameter adaptation allows the system to balance transmission efficiency with acceptable image quality for each specific range.
3Loss of time
If multiple pixel groups are exposed at different timings for one light emission, then sensing time is shortened, but system complexity increases
Solution Approach 1:
The image sensor is segmented into multiple pixel groups, each capable of independent exposure timing control. During one light emission, different pixel groups are exposed at different timings to capture images of objects at different ranges simultaneously. This segmentation allows parallel imaging of multiple ranges, significantly shortening sensing time while adding manageable complexity through structured pixel group organization.
Solution Approach 2:
The patent introduces a temporal dimension to pixel group operation by exposing different pixel groups at different timings within the same light emission cycle. This time-based differentiation allows the system to capture multiple depth ranges in parallel during a single light emission, transforming a sequential process into a parallel one and thereby reducing sensing time despite increased control complexity.
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
The solution improves image quality by reducing noise, shortens the generation time of slice images, and reduces the overall sensing time, enabling more efficient operation of the gated camera system.
Implementation Method 1
The time of flight (TOF) camera projects infrared light by a light emitting device, measures a flight time until reflected light returns to an image sensor
Implementation Method 2
measures a flight time until reflected light returns to an image sensor
Data Source
AI summary
A gated camera divides a depth direction into a plurality of ranges and generates a plurality of slice images corresponding to the plurality of ranges. An illumination device radiates probe light. A controller controls a light emission timing of the illumination device and an exposure timing of an image sensor. An image processing device generates a slice image based on a sensor image transmitted from the image sensor. The image processing device selects M (M≥2) pixel values in ascending order of pixel values for each line of the sensor image, calculates an average value of the M pixel values, and subtracts the average value from each pixel value of the corresponding line.