File reading is runing ultra fast now. We're getting that SD card speed
the STM32 promised now. The file buffer commands have been updated to
alloc as much available memory to read as much of a file in as possible
now to speed up things. This works really great.
Note however, while the file buffer is active you have to use the file
buffer versions of tell and size. Spent a few hours on tracking down an
error related to not using the buffered versions.
All file write functions now use fb_alloc to go much faster. Writes are
re-directed to the extra frame buffer RAM and are grouped until they can
be written in a massive multi-block write to the SD card. We get the
best SD card write speed by doing things this way.
Ideally we'd want to buffer the whole file... but, this is about as good
as we're going to get for now.
Going to fix reading functions to use the same buffer next.
The built-in mjpeg module allows you to record videos seamlessly. It
will automatically compress the frame buffer using the extra space in the
main ram. So... you don't have to pass it jpeg images. Gets 7 FPS at
320x240 while connected to the computer too (it has to compress the
frame twice in this situation).
Anyway, the module work like Gif.
Now you can just grab all the free ram in the frame buffer in one go.
This fixes problems figuring out how many lines to alloc. Will update line
op code with this new info later.
Color gifs look very good for how bad you'd expect them to be with just
7 bits of color (rgb232) - quite amazing. Also, I hardened the gif
module to make it "user ready".
You can now get the color stats for an area in the image. The stats
function returns the mean, median, mode, min, max, st_dev,
lower_quartile, and upper_quartile.
This function allows you to automate binary and threshold functions
based on what's in the iamge.
The morph function lets you convolve the image with a kernel. It's
decently fast right now. But, in the future we'll have to optimize it by
a lot (unrolling loops, using SIMD instructions, etc.).
Anyway, along with morph I added an edge detection test script showing
how you can use a high pass filter on an image to get all the edges in
it. This is not as good as canny edge dection... but, it's about the
same and fast enough.
We'll need a Hough Transform system in the future to make edge dection
useful. Not sure how that will be implemented... so, that's going to be
far away for now.