# Image Analysis
Digital cameras are technological marvels. They packs itself in an accessible package (possibly inside your smart phone?), and can capture high resolutions images and videos conveniently.
This picture-taking process can often with tremendous control over time and scale. Consumer-grade highspeed camera let you capture rapid changes at 1000 frames-per-second (fps), at the same time, time-lapse photography can record changes occurring over hours or days. With dedicated accessories, the shooting can be triggered by sound or light to monitor relatively rare events; strapping on a macro lens (or a microscope lens) could expand the magnification up to 160x, allowing the recording of sub-millimeter objects. What you can record is limited by your imagination.
"Image analysis" describes the process of quantitatively analysing a picture, a method to extract numbers from what you can see. By mastering image analysis you turn qualitative observations into quantitative data.
Possible IA topics
Remember the $\ce{CuSO4.5H2O}$ dehydration lab? You would have noted the "clumpiness" of the solid. Clumpiness is a clumsy term meaning different things to different people; the salt's grain size have little of this ambiguity. By mastering image analysis, you could investigate how fast the salt clumps, by measuring the grain size growth over time --- perhaps with humidity as the independent variable.
Is the rate of sugar crystals grow (from a saturated solution) constant? What about the growth of, say, an calcium alginate shell (like what the chefs use in molecular gastronomy)? These were difficult to investigate, but now made possible by simply taking a picture and analysing the length.
You may want to evaluate the effectiveness of bleach at different dilution. Is 1% bleach a quarter the effectveness as 4% bleach? You could stain cloth, treat them with bleach solutions, and quantify the darkness of the remaining stain. (This turned out so convenient that some students examined about 200 (!) conditions during their Group 4 project.)
Image analysis is a versatile tool and opens up doors where there were walls. The state-of-the-art software, ImageJ, is free, open source, and runs on Windows, OSX, and Linux. If you want to explore, download, install the program, and follow along. We will begin with simple length measurements, and move onto intensity, automated particle counting, and finally, how to enhance your images if they were blurry or not properly light to start with.
# Assessories available
You can borrow the following photography accessories (if you promise to take veeery good care):
- lights equipped with softboxes (250W x 2, 800W x 1),
- tripod,
- microscope lens for smartphone
- up to 320x when optimally stacked; useful for ~0.1---1 mm objects
- self-illuminating (UV/vis)
- dark-field / bright-field microscopy
- macro lens equipped camera (useful for ~1---20 mm objects)
- highspeed camera (up to 1000 fps)
# ImageJ tutorial
# Digital images
# Interface
# Measuring length
uncertainties
# Measuring intensity
uncertainties