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maxritter / diy-thermocam

A do-it-yourself thermal imager, compatible with the FLIR Lepton 2.5, 3.1R and 3.5 sensor with Arduino firmware
http://www.diy-thermocam.net
GNU General Public License v3.0
1.12k stars 174 forks source link

RAM Requirements for ThermoCam #19

Closed xmdfb closed 3 years ago

xmdfb commented 6 years ago

Hi, I know you are using the Teensy 3.6. I was wondering how much RAM memory I would need if I were to choose my own micro controller. How much did you need to process the 160 x 120 thermal images.

maxritter commented 6 years ago

The DIY-Thermocam firmware uses two buffers to store the images:

//320x240 buffer (Teensy 3.6 only) unsigned short bigBuffer; //160x120 buffer unsigned short smallBuffer;

The larger buffer can contain an image with 320x240, so that it can be displayed in the full-screen resolution of the LCD display. This is used to upscale the thermal images with some filtering and therefore provide smoother images. But it is not required for a proper functionality and can be enabled or disabled with the HQ mode setting inside the menu. In addition to that, it is only available on the Thermocam V2 using a Teensy 3.6 MCU with 256K RAM. This array uses 3202402 (16-Bit) = 153.6 kByte

The smaller buffer is required to store a thermal image. It has a memory requirement of 1601202 = 38.4 kByte. The Teensy 3.2 used in V1 of the DIY-Thermocam offers 64kB of RAM. This can be considered as the absolute minimum, if all the other GUI features of the Thermocam (Load / Save / Processing) are used.

So for a short answer, a minimum RAM of 64kB is required, if GUI features are used and HQ mode is disabled. When HQ mode is enabled, 256kB are necessary.

Hope that helps :)

haraldg commented 6 years ago

@xmdfb Out of curiosity: Which microcontroller are you considering? Why?

I note that you seem interessted in smaller microcontrollers while I'd like to see bigger ones (see #5), but I'm still interested what criteria other people have.

Meins321 commented 5 years ago

So the lepton gives 320x240x16=1228800bits 1228800bits/8= 153600 bytes so (kilo=1000) gives 153,6 kilobytes... or 150kb if you devide by 1024 :-)