Not really about Paramecium

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

Moderators: MacroMike, nzmacro, Ken Ramos, twebster, S. Alden

Locked
User avatar
gpmatthews
Posts: 539
Joined: Tue Apr 27, 2004 11:54 am
Location: Horsham, UK
Contact:

Not really about Paramecium

Post by gpmatthews »

Image

I haven't posted a lot in the last week - I just wanted to prove I haven't been idle or even sidetracked by such mundanities as work -

Well, yes, I wanted to start off with this image of paramecium, but thought it was a good jumping off point for some more wide ranging comments. The image is from a sample from Warnham Millpond kept about a week and taken using my Zeiss GFL with a 19th century Ross 1/4" (x30) objective and Watson x8 compensating eyepiece. Camera is a Canon Powershot S50. The area shown is most of the original image, with some cropping to remove redundant space.

A common problem with observing freshwater life is that of heat from the lamp killing the specimen. I decided to try replacing the lamp with a white LED (see http://www.microscopy-uk.net/mag/artmay04/iwled.html for general details). I fabricated a mount for a 8000 mcd LED such that it was positioned where the filament for the lamp in the Zeiss GFL normally sits. I found that it worked well without a diffuser. It gives cold light both in terms of lack of heating and also in terms of the "feel" of the colour - white with a tendency towards blue. Despite comments in the above Micscape article, the intensity is a little low for darkgound, but the lighting quality is otherwise excellent. To get back to the Paramecium - this was taken using LED illumination and I'm fairly pleased with the result. I replaced the 68 ohm resistor shown in the circuit diagram with a series "idiot" diode to protect against accidental polarity reversal and a 22 ohm resistor.


The image has been further processed digitally, which brings me to my next comments. Although I possess Photoshop 6.0, I generally use Paint Shop Pro 9 for image processing. I find it very flexible and I'm more familiar with it than Photoshop. It also accepts Photoshop plug-ins. The above image has been adjusted for contrast and colour balance to remove some of the LED blueness and sharpened on resizing. I looked at noise reduction, but it tended to remove the cilia. I wondered whether the presence of a little noise also enhances the perception of some features (similar to stochastic noise enhancement sometimes used to enhance perception of audio signals in radio reception). Other features that are new in PSP that may appeal to microscopists are a chromatic aberration filter, and flash fill and backlighting filters. These latter allow adjustment of foreground vs background brightness and contrast. I used chromatic aberration filtering to remove some very slight blue fringeing.

The scale bar was added from a library of scale bars which are kept as separate layers in images of a stage micrometer for each microscope/objective/eyepiece combination (camera always at full, non-digital, zoom). The layer is just copied and pasted into the image - image pixel resoution has to match, of course.

I hope there are some useful thoughts here.
Graham

Charles Krebs
Posts: 1200
Joined: Tue Jul 13, 2004 10:50 am
Location: Issaquah, WA USA

Post by Charles Krebs »

Graham... something I've found helpful when I've got a "noisey" image but using noise reduction kills the fine detail. Often I mainly want to get rid of the noise in the detail-less background where it is really noticeable. I create a duplicate layer, and do a "global" noise reduction on the top layer. Then "erase" through the top layer to reveal only the subject from the bottom layer. (I agree that sometimes a bit of noise... within reason... in a detailed subject is not always objectionable, and may even seem to enhance sharpness.) It's much faster than messing around with masks, and can work well for microscope images where you often have a subject sitting in a blank background. I've also found that a program called Neat Image is better than most routines at getting rid of "noise" in a large number of pictures without messing up the fine detail much at all.

User avatar
gpmatthews
Posts: 539
Joined: Tue Apr 27, 2004 11:54 am
Location: Horsham, UK
Contact:

Post by gpmatthews »

I used to use Neat Image, but decided that PSP 9 offered a better and more convenient method. Also seems faster.

I'll have to play around with some of the noise reduction tricks you describe, Charlie.

Cheers
Graham

Locked