Histogram Interpolation for ToF Distance Measurement Accuracy
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Solution Overview
Problem
In distance measurement using the time of flight (ToF) method with pulse light, reliability is low when measuring a single pulse, and accurate distance information is difficult to obtain in scenarios with overlapping objects, such as those behind a wire mesh, due to the limitations of averaging multiple measurements.
Innovation Solution
The signal processing apparatus generates a distance histogram for each pixel by interpolating based on nearby pixel distances, using weight information determined by correlation direction, distance, and luminance differences, and performs upsampling to improve accuracy and reduce data transmission requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple distance measurements are averaged to improve reliability, then measurement reliability improves, but accuracy deteriorates in cases with overlapping objects
Solution Approach 1:
The patent segments the distance measurement results by creating a distance histogram that separates measurements into discrete bins. Instead of averaging all measurements together, the histogram segments them by distance value, allowing overlapping objects at different distances to be distinguished. This resolves the contradiction by maintaining reliability through multiple measurements while preserving accuracy through segmentation of the results.
Solution Approach 2:
The patent transforms the one-dimensional averaging approach into a two-dimensional histogram representation, where the x-axis represents distance and the y-axis represents frequency. This dimensional transformation allows the system to maintain multiple measurement data points (improving reliability) while visually and computationally separating overlapping objects at different distances (preserving accuracy).
2Measurement precision
If distance histogram is generated for each pixel to improve accuracy, then measurement accuracy improves, but data transmission bandwidth increases
Solution Approach 1:
The patent extracts only the essential information from the full distance histogram by identifying and transmitting only the peak distance values and their frequencies. Instead of transmitting the complete histogram data for each pixel, it extracts the key distance information needed for accurate measurement, significantly reducing transmission bandwidth while maintaining measurement accuracy.
Solution Approach 2:
The patent applies local quality optimization by processing and transmitting distance information selectively. Rather than uniformly transmitting all histogram data across the entire image, it focuses transmission on pixels containing actual objects (identified through peak detection), reducing overall data transmission while maintaining accuracy for relevant regions.
3Measurement precision
If pixel interpolation is performed on histogram image to improve accuracy, then measurement accuracy improves, but processing complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing the distance histogram for each pixel before interpolation is needed. This allows the interpolation process to simply reference pre-computed histogram data from neighboring pixels, significantly reducing processing complexity compared to calculating histograms during the interpolation step itself.
Solution Approach 2:
The patent uses copying by replicating the histogram data structure from neighboring pixels during interpolation. Instead of performing complex calculations, it copies and combines histogram data from adjacent pixels according to interpolation weights, simplifying the processing while maintaining 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 enhances the accuracy of distance measurement by effectively handling overlapping objects and reduces data transmission bandwidth through improved interpolation and upsampling techniques.
Implementation Method 1
a light reception unit 22 that receives the light 2 reflected by the target object and generates a reception signal
Data Source
AI summary
A pixel is appropriately interpolated regarding a histogram image in which a distance histogram is allocated to each pixel position. A signal processing apparatus according to the present technology includes a histogram generation unit that inputs a histogram image in which a distance histogram indicating results of a plurality of times of distance measurement as frequency information for each distance is allocated to each pixel position and generates a distance histogram of an interpolation target position in the histogram image on the basis of distance histograms of a plurality of pixel positions near the interpolation target position.