Pipette Tip Detection Using Grid-Based Image Analysis
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Solution Overview
Problem
Current laboratory workstations face difficulties in reliably determining the presence or absence of disposable pipette tips in pipette tip holders due to optical distortion and interference from neighboring tips, especially with black tips in dark holders, making it challenging to assess occupied versus empty holes using digital cameras.
Innovation Solution
The method involves using an evaluation unit to record digital images of pipette tip holders, defining a perspectively adapted orthogonal grid, dividing grid elements into quadrants, and determining pixel brightness within these areas to determine the presence of disposable pipette tips based on predetermined threshold values, using reference and transit images to accurately identify occupied holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a digital camera is used to record pipette tip holders, then the automation and efficiency of the laboratory workstation is improved, but the measurement precision of determining occupied versus empty holes deteriorates due to optical distortion and interference
Solution Approach 1:
A reference image is introduced as an intermediary to establish a distortion-free coordinate system. This reference image serves as a mediator between the distorted real-time images and the actual physical positions of receiving holes, enabling accurate hole occupancy determination despite optical distortion
Solution Approach 2:
The system transforms the image data by applying coordinate transformations based on the reference image. This parameter change converts distorted image coordinates into accurate physical coordinates, allowing precise determination of hole occupancy status
2Ease of manufacture
If black disposable pipette tips are used in dark pipette tip holders, then the cost and standardization is improved, but the difficulty of detecting and measuring hole occupancy increases due to low contrast
Solution Approach 1:
The system utilizes color or brightness differences between the pipette tip and the holder as the detection basis. By analyzing the contrast in the captured images and comparing with reference data, the system can identify occupied holes even when the color contrast is subtle
Solution Approach 2:
The patent replaces manual visual inspection with an automated image processing system. The evaluation unit automatically analyzes the captured images, eliminating the need for human operators to manually detect the subtle contrast differences between black tips and dark holders
3Area of stationary object
If neighboring disposable pipette tips are present in the field of view, then the complete imaging of the work area is improved, but the measurement precision deteriorates due to interference and shadow effects
Solution Approach 1:
The image processing system divides the overall image into individual regions corresponding to each receiving hole. By segmenting the analysis into discrete hole-level evaluations, the system can accurately determine occupancy status of each hole without interference from neighboring tips
Solution Approach 2:
The evaluation is performed locally for each receiving hole based on its specific image characteristics. The system analyzes the local region around each hole independently, considering only the relevant visual information for that specific hole, thereby eliminating interference from other areas
Data Source
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Figure 3A~5
Figure 6~7
AI summary
The invention relates to a method for determining the presence or absence of disposable pipette tips (1) in pipette tip carriers (2) on the work area (3) of a laboratory workstation (4). Each of the pipette tip carriers (2) has a support panel (5) with receiving holes (6) into each of which a disposable pipette tip (1) can be inserted. The laboratory workstation (4) for carrying out the method comprises a robot arm (7) with at least one pipette (8) which is designed to receive and dispose of disposable pipette tips (1). The laboratory workstation (4) comprises a digital camera (9) which is arranged on a support device (10) and is operatively connected to an analyzing unit (11). The work area (3) of the laboratory workstation (4) can be completely imaged in at least one first direction using the digital camera (9). The method has the steps of selecting pipette tip carriers (2) arranged on the work area (3) of the laboratory workstation (4); capturing at least one digital image (12) of each pipette tip carrier (2); defining an initially orthogonal grid (14), which is adapted to the perspective of the digital image (12) and which comprises quadratic grid elements (13), on each of the pipette tip carriers (2); determining pixel areas (15) in a digital image (12), said pixel areas be assignable to individual grid elements (13), wherein each grid element (13) of the defined grid (14) is divided into four quadrants (18); ascertaining the number of pixels with a specified brightness in the specified pixel area (15); and determining whether a disposable pipette tip (1) is present or not in a specific receiving hole (6) of a pipette tip carrier (2).