Depth Camera Volume Measurement With Countertop Height Correction

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Solution Overview

Problem

Existing volume measurement methods using depth cameras suffer from inaccuracies due to installation issues and non-uniform height measurements, especially when objects extend beyond the measurement platform, leading to incorrect volume calculations.

Innovation Solution

A method utilizing countertop empirical equations to simulate depth images, selecting a target image with the highest correlation to the actual countertop shape, and calculating object height based on this to improve measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the depth camera is used to measure object volume directly, then the measurement process is simple, but the measurement precision deteriorates due to installation inaccuracies and non-uniform countertop height

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoidobject height measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent performs preliminary scanning of the reference countertop to generate a depth image before measuring the object. This preliminary action captures the actual height variations of the countertop surface, which are then used to correct subsequent object measurements, thereby improving measurement precision without complicating the overall process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a depth image copy of the reference countertop surface and uses this copied data to establish a height correction model. This copying approach allows the system to reference the actual countertop geometry without requiring physical contact or complex calibration procedures during object measurement

Inventive Principle:
Principle #26Copying

2Device complexity

If the centre point height of the measurement platform is used as reference, then the calculation is simple, but the measurement precision deteriorates when objects extend beyond the platform boundaries

Engineering Contradiction:
Improvecalculation complexityVSAvoidobject height measurement accuracy for extended objects
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from using a single centre point reference to a local quality approach where each pixel in the depth image has its own height correction value based on its position. The height correction model provides location-specific adjustments, ensuring accurate measurements for objects extending beyond the platform while maintaining computational efficiency through pixel-level parallel processing

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple depth measurements are taken to improve accuracy, then the measurement precision improves, but the measurement time increases

Engineering Contradiction:
Improveobject height measurement accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs the time-consuming depth scanning and height variation analysis as a preliminary action before object measurement. This single preliminary scan creates a reusable height correction model that can be applied to multiple object measurements without requiring repeated scanning, thereby improving precision while minimizing additional measurement time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the reference countertop itself to generate the correction data needed for accurate measurements. By scanning the countertop once and using its own depth variations to correct subsequent measurements, the system achieves high precision without requiring multiple external calibration objects or repeated measurement cycles

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4330622B1Volume measurement method and an apparatus based on a depth camera, and a computer-readable medium
Publication Date: 2026.01.21 METTLER TOLEDO (CHANGZHOU) MEASUREMENTTECHNOLOGY LTD
  • EP4330622B1 patent drawingFigure 1A~1B
  • EP4330622B1 patent drawingFigure 2
  • EP4330622B1 patent drawingFigure 3

AI summary

The present invention relates to a volume measurement method and apparatus based on a depth camera, and a computer-readable medium. The method includes: acquiring a first depth image of a reference countertop, where the first depth image includes coordinate data and depth data of a plurality of pixels, and the reference countertop is adapted to the placement of a measured object; substituting the coordinate data and the depth data into at least two countertop empirical equations, to obtain at least two simulated images, wherein each of the countertop empirical equations is used to represent a height variation pattern of the reference countertop; calculating a correlation between each of the simulated images and the first depth image; using a simulated image with the highest correlation as a target image of the reference countertop; and obtaining a countertop height of the reference countertop based on the target image, wherein the countertop height is used to calculate a height of the measured object, and the height is used to calculate a volume of the measured object. The present invention improves the accuracy of object volume measurement.