extracting avocado fruits from an image (band780).

I need to extract avocado fruits from an image (band780). besides avocado there are trees and leaves.

In the code now looks like this but the main problem is that i cannot mask out the background as it is not clear what exactly is a background here

%original image

x = imread('REF_024_11072018_084046937_780.TIF');

imshow(x)

title('Raw Image')

%color map

% figure

% imshow(x)

% colormap jet

% title('Jet color map')

%histogram stretch

h=histeq(x);

figure

imshow(h)

title('histogram')

%Negative Histogram

ng = max(h) - h;

figure

imshow(ng)

colormap jet

title ('Negative Histogram')

%invert

n = ng - x;

figure

imshow(n)

title Invert

%background estimation (non uniform illumination)

% bg = imopen(x,strel('disk',10));

% figure

% imshow(bg)

% colormap jet

% title Background

% %Negative Background

% ng = max(bg) - bg;

% figure

% imshow(ng)

% colormap jet

% title ('Negative Background')

%background removal (flatten background level)

% y = imsubtract(x,bg);

% figure

% imshow(y)

% title Flattened

%segment grains from background

bw = im2bw(n,graythresh(n));

figure

imshow(bw)

title GrayThreshed

%edge detection

%sobel

edgeS = edge(bw,'sobel');

% BW2 = edge(bw,'canny');

figure

imshow(edgeS)

title Edge

%label connected regions