NOAA Scallop Measurement System
In 2009, we were selected to design and install an automated measurement system to measure the “height” of scallops. The manual method used by NOAA personnel is shown below. The goal of the system was to evaluate the use of cameras to automate and improve the measurement process.
The Albatross is used by NOAA to collect data on scallop population health, among other things.
Scallop diameters are measured by hand.
A board is used to determine the height.
Our system consisted of a transparent belt with a backlight to produce a binary image of the scallop in silhouette. The ISG 1394 LightWise camera ran continuously to provide images which were processed using functions from the LabVIEW Vision Library to extract the area and effective diameter of each scallop. Final results showed excellent consistency with the actual shell height. [Click images to enlarge]
Measurement system in test lab in Woods Hole, Mass.
Scallops loaded onto conveyor
The basic algorithm runs at 30 frames per second. A ‘soft trigger” determines if a new scallop has entered the camera field of view (moving right to left). It then saves and crops the image for analysis. Small particles are filtered and scallops are identified. The leftmost scallop is isolated for measurement. [+ Click any image to enlarge]
Detect scallop using “soft trigger” region
Crop test region
Filter small particles
Isolate scallop and measure area
Acceptance criteria were demonstrated by comparing the actual measurement (using calipers by hand) with the MVS measurement calculated by the vision system. The test was performed on a sample set designed to verify operation over the full range of expected scallop sizes (1 to 10-inch height).
The attached Article was published in Vision System Design magazine in 2009.
