RaySuhyunLee

import random
import time

temp = 50

x = 30
pe = 2
re = 2
k = 0

RaySuhyunLee

Overview

0. (if wifi with password) use wpa_passphrase to set proper password
1. use wpa_supplicant to associate
2. use dhclient to obtain an ip address
3. use ifconfig to check ip address

iwconfig wlan0 # check wifi card status
iw wlan0 scan | less # check available access points

RaySuhyunLee

how and and & work in python

You may consider that python's and is equivalent to c's &&. But and in python works quite differently.

>>> True and True
True
>>> False and True
False

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Those are list of problems you may encounter while using opencv.

[nx video] failed to subdev set_fmt() ...

These kind of error may occur when you try to stream from webcam, in linux. Internally, opencv depends on v4l(video4linux) to access webcam data. This error means that the camera doesn't support your requested format, eg.frame size, frame rate, color(rgb, yuv, ...). Check spec of your webcam again and provide correct options when you open it.

RaySuhyunLee

FROM       ubuntu:16.04
MAINTAINER raysuhyunlee@gmail.com

RUN apt-get -y update
RUN apt-get upgrade
RUN apt-get install -y build-essential cmake pkg-config \
  libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev \
  libavcodec-dev libavformat-dev libswscale-dev \
  libxvidcore-dev libx264-dev libxine2-dev \
  libv4l-dev v4l-utils \

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grep

search string in files

$ grep "string"

$ grep -r "string" # find recursively
$ grep -r -i "string" # dont' care upper/lower case

RaySuhyunLee

OpenCV arm용으로 포팅하기

arm은 크게 armel과 armhf 아키텍쳐로 나뉜다. 어떤 아키텍쳐를 쓰느냐에 따라 사용하는 컴파일러/툴체인이 달라진다. https://stackoverflow.com/questions/26692065/difference-between-arm-eabi-arm-gnueabi-and-gnueabi-hf-compilers

다음과 같은 커맨드로 확인할 수 있다. 자세한 것은 아래 링크 참조

$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args

https://blogs.oracle.com/jtc/is-it-armhf-or-armel  

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http://www.pfeiferindustries.com/timing-belt-pulley-pitch-diameter-outside-diameter-charts-i-12-l-en.html

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#!/bin/bash

echo "install rpm package manager"
sudo apt-get install rpm2cpio

echo "install tizen sdk"
wget http://download.tizen.org/sdk/Installer/tizen-sdk-2.4-rev4/tizen-web-cli_TizenSDK_2.4.0_Rev4_ubuntu-64.bin
sudo chmod +x tizen-web-cli_TizenSDK_2.4.0_Rev4_ubuntu-64.bin
./tizen-web-cli_TizenSDK_2.4.0_Rev4_ubuntu-64.bin
rm tizen-web-cli_TizenSDK_2.4.0_Rev4_ubuntu-64.bin

RaySuhyunLee

좋은 링크: http://www.heystephenwood.com/2012/08/ssh-tunneling-on-mac-in-5-minutes.html

Mac

ssh -D [port] root@test.com

sss -D 8888 blabla@raysuhyunlee.net