Otolith image analysis systems
Learn about image analysis systems, applications and our system setup.
On this page
About image analysis systems
We take advantage of computer-assisted microscopic imaging techniques, or image analysis, for almost all otolith examinations we carry out in our laboratory.
With image analysis, we can achieve accuracy and speed that can’t be matched with the eyes or a microscope alone. These systems allow for image:
- storage
- manipulation
- quantification
- enhancement
In its simplest form, an image analysis system can:
- store an image from a:
- scanner
- camera
- computer
- microscope
- allow us to recall and display the image
- reproduce the original image, unaltered
In practice however, images entered into a system are generally enhanced and/or measured before re-display. This is their advantage over visual examination.
System applications
Image analysis systems are now routine in many scientific disciplines, and their applications to otolith examinations are numerous. Some of the most frequent applications to our work include:
- image enhancement of contrast and detail in the image, including that which is invisible to the eye, through:
- histogram expansion
- filters (convolutions)
- edge detection algorithms
- image quantification, including:
- semi-automated and automated counts
- measurements of structures visible in the image, such as calibrated measurements of growth increments and otolith size, our most common form of measurement
- shape analysis, a procedure that is almost fully automated and includes:
- measurements of otolith length and area
- conversion of the outline to Fourier components
- image storage of:
- existing reference collections
- subsamples of routinely imaged and enhanced otolith cross sections
- images of enhanced intact otoliths before submission for publication in the photographic atlas
Our system setup
Our image analysis system.
Our image analysis system includes:
- photo editing software
- image analysis software
- a computer with 1 TB disc storage
- 27" LCD monitor working at 1920 x 1080 resolution
- colour printer, scanner and copier that prints at 9600 x 2400 dpi
- dissecting microscope and compound microscope on which the video camera can be mounted
- high-resolution (4140 x 3096 pixels) colour charge-coupled device (CCD) digital video camera
Routine image analysis procedures don’t require this high-resolution system. For example, the ageing unit at the Bedford Institute of Oceanography uses image analysis systems supporting only 800 by 600 resolution for annual age determinations in support of stock assessments.
Related links
- Date modified: