error "The expression to the left of the equals sign is not a valid target for an assignment."

I run a test program shown below:

clear all;
clc;
image_a = imread('doll_full_color','png');

histo = histogram(image_a);

error comes:

??? Error: File: histogram.m Line: 12 Column: 30
The expression to the left of the equals sign is not a valid target for an assignment.

Error in ==> test_his at 5
histo = histogram(image_a);

For your information, histogram is a function I defined to calcuate the histogram of an image,shown below:

function [ histo ] = histogram( image )
%UNTITLED3 Summary of this function goes here
%   Detailed explanation goes here
clc;
[row, column] = size(image,3);
histo = zeros(256,3);
histo_sum = zeros(256,3);
for m=1:1:3
for i=0:1:255
    for j=1:1:row
        for k=1:1:column
            if( image(j,k,m) = i)
                histo_sum(i,m) = histo_sum(i,m) +1;
            end
        end
    end
end
end

histo = histo_sum/(row*column);

end

Anyone can help solve the problem? Thank you!

Answer 1

[Walter Roberson]

The comparison operator is ==

if( image(j,k,m) == i)

[Jiayuan]

thank you, ya, I found this one, you are right.

Answer 2

[supriya]

I m not sure but try this...

image_a = imread('doll_full_color.png'); histo = histogram(image_a);

[Jiayuan]

thanks, problem is solved, referring to Walter Roberson's answer.

Answer 3

[zhang]

but how to solve the problem blew:

 clear all
t0=0;
dt=0.05;
t1=1;
tf=5;
t=[t0:dt:tf];
st=length(t);

n1=floor((t1-t0)/dt) x1=zeros(1,st); x(n1)=1/dt; subplot(2,2,1),stairs(t,x1),grid on

x2=[zeros(1,n1-1),ones(1,st-n1+1); subplot(2,2,3); stairs(t,x2); grid on w=10;; u=-0.5; x3=exp((u+j*w)*t); subplot(2,2,2),plot(t,real(x3)),grid on; subplot(2,2,4),plot(t,imag(x3)),grid on;

hope some can solve my problem!

[Walter Roberson]

Missing ] after x2=[

Answer 4

[dorai raj]

The expression to the left of the equals sign is not a valid target for an assignment

Answer 5

[dorai raj]

i want h=1.3,where h=c/d:c=(n/m),m=(a/b)

n=1;
m=(1:10);
a=5;
b=(0.3:6);
while h>(c./d);
    c=(n./m);d=(a./b);
    h=1.3; 

[Walter Roberson]

Your code is missing an end statement.

Please post your actual code.

[dorai raj]

where h=c/d,

c=(n/m),m=(a/b)

n=2

m=0.1 to 8

a=1

b=0.4 to 9

how to get h=1.3?

[Walter Roberson]

c = n/m, m = a/b implies that c = n/(a/b) --> c = n*b/a

n and a are known values 2 and 1, so c = 2*b/1 --> c = 2*b

m is a/b where a = 1, so m = 1/b and m is restricted to 0.1 to 8 so that implies that b is restricted to the range 1/8 to 10 . But b = 0.4 to 9 which is a tighter restriction on both sides. The actual range of m is therefore 1/9 to 5/2

c = n/m and n = 2 and m is 1/9 to 5/2 so c = 2/(1/9 to 5/2) so c is in the range 2/9 to 5

h = c/d so h = (2/9 to 5) / d = 1.3 . So d = (2/9 to 5)/(13/10) which is 20/(9*13) to 50/3 which is about 0.171 to 16 2/3 .

There is not unique solution.