Calculate Spray cone angle

I have an image of result of multi hole injector

and I want to get the cone angle of one hole.

Therefore, this is my code, but the code give me wrong angle and I want to get the result that the background of clipped image is gone but the background still remains white. How can I fix it ??

clear all

close all

clc

casenumber = 1;

for casenumber=1:1

load_path = strcat('D:\JY\HHM\Spray_diesel\tecplot_image\clipped'); %경로지정

subt_path = strcat(load_path,'\subt');

save_path = strcat(load_path, 'D:\JY\HHM\Spray_diesel\tecplot_image\clipped'); %저장 경로

disp(save_path)

cd(load_path)

k=0;

yt=1168/2; yb=1168; xl=1; xr=1168; %% 사진 크기 기준

center=(xr-xl)/2;

Ratio=100/(xr-xl);

length=yb-yt+1;

%% Mie scattering

i=10;

for j=1:50

k=k+1;

cd(load_path)

filename=strcat('0.00', int2str(i), '.png');

filenamebw=strcat('0.00',int2str(i),'_bw','.png');

if i<=1000

filename=strcat('0.000', int2str(i), '.png');

filenamebw=strcat('0.000',int2str(i),'_bw','.png');

end

if i<=100

filename=strcat('0.0000', int2str(i), '.png');

filenamebw=strcat('0.0000',int2str(i),'_bw','.png');

end

i=i+100 ;

I_m=imread(filename); %% 사진 읽기

%I_m=I_m(yt:yb,xl:xr,:); %% 사진 자르기 [yt:yb,xl:xr]

%triangle_x=[center-200 center center+200];

%triangle_y=[yb yt yb];

%I_masked=roipoly(I_m,triangle_x,triangle_y);

Isize=size(I_m);

mask = poly2mask([center-200 center center center+200],[yb yt yt yb], Isize(1,1), Isize(1,2));

I_masked = bsxfun(@times,I_m,cast(mask,class(I_m)));

I_masked =I_masked(yt:yb,xl:xr);

mask =mask(yt:yb,xl:xr);

%I_masked = bsxfun(@times,I_m,cast(mask,class(I_m)));

%I_masked=image(I_masked,'alphadata',1-double(all(mask,3)));

%I_masked=bsxfun(@eq,I_masked,mask);

%I_masked=eq(I_masked,mask);

%mask=bsxfun(@eq,I_masked,reshape([0 0 0],1,1,3));

%I_masked=image(I_masked,'alphadata',1-double(all(mask,3)));

%I_masked=imread(I_masked);

%% Mie image processing

I_masked_modified=I_masked;

%I_masked_modified=immultiply(I_masked,3.5); %% 이미지 밝기 보정

imwrite(uint8(255 - I_masked_modified),filenamebw); %% 이미지 흑백 반전

I_masked_modified_inversed = imread(filenamebw);

threshhold_m=245/256;

threshhold=100/256;

BinaryI_m = im2bw(I_masked_modified_inversed,threshhold_m); %% 2진 사진으로 변경

I_masked = im2bw(I_masked_modified_inversed,threshhold);

seD1 = strel('disk',1); %% 원형 모양 벡터 생성 1포인트

BinaryI_m = imdilate(BinaryI_m, seD1); %% 원형 모양 벡터로 이미지 부풀리기

BinaryI_m = imdilate(BinaryI_m, seD1);

BinaryI_m = imdilate(BinaryI_m, seD1);

BinaryI_m = imdilate(BinaryI_m, seD1);

BinaryI_m = imdilate(BinaryI_m, seD1);

BinaryI_m = imfill(BinaryI_m, 'holes'); %% 구멍난 부분 메우기

BinaryI_m = imerode(BinaryI_m, seD1); %%다시 깎기

BinaryI_m = imerode(BinaryI_m, seD1);

BinaryI_m = imerode(BinaryI_m, seD1);

BinaryI_m = imerode(BinaryI_m, seD1);

BinaryI_m = imerode(BinaryI_m, seD1);

Area_m=bwarea(BinaryI_m); %%bwarea=이진영상의 객체 면적

%

if Area_m>0

%% %%%%%%%%%%%%%% penetration length %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% 인젝션 팁 시작지점은 사진에서 직접 좌표를 찾아서 [x,y]좌표를 넣어줘야한다.

L_m=logical(BinaryI_m);

stats_m = regionprops(L_m, 'Area', 'Centroid','BoundingBox'); %%regionprops=이진영상의속성측정

areas_m = [stats_m.Area];

BoundingBox_value = [stats_m.BoundingBox];

[m,n] = size(BoundingBox_value) ;

xbottom_length=0;

for l=8:4:n

bottom_length = ((BoundingBox_value(l)+BoundingBox_value(l-2)-0.5)*50/length) ;

if xbottom_length<bottom_length

xbottom_length = bottom_length ;

end

end

pene(k,1)= (i)*0.0001

pene(k,2) = xbottom_length

%Table = table(pene,xbottom_length)

end

BWboundary=bwboundaries(BinaryI_m);

[x,y]=size(BWboundary);

%% cone angle

I_2=BinaryI_m+mask;

[rows,columns]=size(BinaryI_m);

leftedge = zeros(1,rows);

rightedge = zeros(1,rows);

rows=rows/50;

for row=1:rows

%thisrow=BinaryI_m(row,:);

leftindex = find(I_2==2, 1, 'first');

if ~isempty(leftindex)

leftedge(row)=leftindex;

rightedge(row)=find(I_2==2, 1, 'last');

X=1:585;

Y = leftedge(X);

leftCoefficients = polyfit(X, Y, 1);

leftAngle = atand(leftCoefficients(1));

Y = rightedge(X);

rightCoefficients = polyfit(X, Y, 1);

rightAngle = atand(rightCoefficients(1));

coneAngle = abs(leftAngle) + abs(rightAngle);

%coneAngle = coneAngle*cosd(15) ;

end

end

result = table((i)*0.0001,xbottom_length,leftAngle,rightAngle,coneAngle)

%% 이미지 출력

figure(1)

imshow(I_masked);

hold on

for j=1:x

C_m=cell2mat(BWboundary(j,1));

plot(C_m(:,2),C_m(:,1), 'y','LineWidth',2)

%yy=zeros(20,1);

%yy(j,1)=max(C_m(:,1));

hold on

end

hold off

% BWoutline = bwperim(BW_final1_m);

% Segout = I_obj_m;

% Segout(BWoutline) = 255;

% figure (2); imshow(Segout);

% yyy=max(yy);

%

% P_distance_m=(yyy-offset)*Ratio;

%

% LiquidArea_m(i, casenumber)=Area_m;

% LiquidPL_m(i, casenumber)=P_distance_m;

% save_path=save_path;

%if exist(save_path,'dir')==0

% mkdir save_path

% end

% imwrite(I_mm, savename);

%cd save_path

%print('-djpeg', savename)

end

end