i am new to Matlab. I wanna write a code to calculate total emissivity foa given surface temperature T

I want to write a code to calculate total emissivity of a surface for a given surface temperature T.

Answer 1

[Image Analyst]

I don't believe this can be calculated from the image. Or if it could be it would require a ton of information about the image, like focal length, working distance, exposure time, etc. The emissivity of a material is an intrinsic property of the material, just like mass density, color, hardness, etc. As you know, when you use your thermal camera, the emissivity is something you have to plug into the camera settings in order to get the accurate temperatures. If you don't plug in the right value for emissivity you get just arbitrary values for temperature, not the true temperatures.

Perhaps you have some different, non-standard definition of emissivity. You should look up optical SI units in Wikipedia. The real world units of a gray level image are proportional energy - like ergs or joules. Ask if you can't figure out why. Maybe you just want to sum up all the pixel values or something.

Answer 2

[prima parvin]

Hi. I need help about that image. How I can generate the code in MATLAB?

[Image Analyst]

See this link

Answer 3

[addisu amare]

Lx = 0.1; % m, maximum length in x-direction

Ly = 0.1; % m, maximum length in y-direction

Hmax = Lx/10; % m, maximum mesh spacing

kt = 16; % W/m-K, thermal conductivity

epsilon = 0.9; % emissivity

T_inf = 10; % K, temperature of surroundings

T_b = 100; % K, temperture of base

% Create PDE thermal model container

thermalmodel = createpde('thermal','steadystate');

% Create 2D geometry and append geometry to model

R1 = [3;4;0;Lx;Lx;0;0;0;Ly;Ly];

gd = R1; % geometry description matrix

sf = 'R1'; % set formula

ns = char('R1')'; % name space matrix

dl = decsg(gd,sf,ns); % decomposed geometry matrix

pg = geometryFromEdges(thermalmodel,dl);

% Set boundary conditions and thermal properties

BC1 = thermalBC(thermalmodel,'Edge',1,'Temperature',T_b);

BC2 = thermalBC(thermalmodel,'Edge',2:4,'Emissivity',epsilon,…

'AmbientTemperature',T_inf);

thermalmodel.StefanBoltzmannConstant = 5.670373E-8; % W/m^2-K^4

mtl = thermalProperties(thermalmodel,'ThermalConductivity', kt);

% Generate mesh, solve problem, and plot results

msh = generateMesh(thermalmodel,'Hmax',Hmax);

thermalmodel.SolverOptions.ResidualTolerance = 1.0e-05;

results = solve(thermalmodel);

pdeplot(thermalmodel,'XYData',results.Temperature,'ColorMap','jet');