Playing with ImageMagick

For some Slow Scan TV (SSTV) experiments I want to be able to overlay text on images from the command line or within a script. The Swiss-army-knife of image manipulation is ImageMagick, so I’m using that.

Starting with a a photograph I took a few years ago, I resized it to 320×256 pixels – that’s the Martin-1 SSTV mode frame size.

An SSTV sized image I want to overlay text on

I can then use the following ImageMagick command to add some text in a shaded box.

convert  -fill white -background '#00000080' -gravity North -size 320x40 caption:'G7UVW SSTV' small-electronics.png +swap -gravity north -composite small-electronics-captioned.png

For now it just adds simple static text, but in production it’ll add dynamic data as well as static text, for example, computer load, camera pointing and RF subsystem data.

Captioned SSTV Frame


Oak leaf wine. Part one.

I’m not quite sure where I can upon the idea of Oak Leaf wine, but after the success last year with Dandelion wine, it seemed a fun idea to brew with oak leaves.  There are a few recipes  floating around the ‘net and published in wine making books, I decided to use this “young oak leaf” recipe.

A Saturday morning stroll around the local park provided a plastic carrier-bag full of tasty oak leaves. A carrier bag-full being my guesstimate of how many I’d need – it’s very scientific this wine making lark.

Back at the shed the leaves were washed with cold water and picked over to remove any bugs, twigs and detritus. They were transfered to a large pan and had around five pints of boiling water poured over them; they were then covered and left to steep for around thirty six hours.

After steeping, the leaves looked like this. Mmmmm, yum.

The recipe calls for three pounds of sugar; and the juice and grated zest of two oranges and a lemon. The leaves are moved from the liquid – the must, the sugar, zest and juice are added and the whole lot brought to the boil.

The zest of one orange and one lemon

The smell at this point is essentially that of oranges with a faint cabbage water undertone. I wasn’t brave enough to sample the must.

Boiling the oak leaf wine must
Filtering the solids from the cooling must

After a good vigorous boil, the must was left to cool to about room temperature before filtering though a coarse gauze mesh, removing any large solids – bits of leave, the zest, etc.

Oak leaf must, with an added campden tablet

At this point the recipe suggest adding the yeast and nutrient. I decided against this and added a campden tablet instead to make sure the must was thoroughly sterile. I’ll add the yeast and start the fermentation going in a day or so, once the tablet has had time to work and neutralise.