Converting a 16bpp bitmap image to c data array (RGB565 format)...

Hi,

    I'm having an 16bpp & 320x340 bitmap image. And i need to get an c 1-D data array.

I used the following command,

A = imread('MyImage.bmp');
RGB = im2uint8(A);

Now i got three matrix, each for R, B & G. And each matrix's element size is 8-bit. It means, i think ,i got RGB888 format.

But i want RGB565 format for the input image.

Kindly help me to get single 1D array of each pixel in the image.

Have a nice day.

- Lenin

Answer 1

[Anaghaa]

Hi Lenin!

To convert the 16bpp 320x340 bitmap image to a single 1D array in RGB565 format, follow the steps:

• Extract the R, G and B components from the image.

    R = A(:,:,1);
    G = A(:,:,2);
    B = A(:,:,3);

• Convert to RGB565 format to reduce the bit depth of each color component.

    R5 = bitshift(uint16(R), -3); % converts the 8-bit red values to 5 bits.
    G6 = bitshift(uint16(G), -2); % converts the 8-bit green values to 6 bits.
    B5 = bitshift(uint16(B), -3); % converts the 8-bit blue values to 5 bits.

• Combine into a Single 16-bit Value.

    RGB565 = bitshift(R5, 11) + bitshift(G6, 5) + B5; 
    % combines the R5, G6, and B5 components into a single 16-bit integer for each pixel.

• Convert to a 1D Array.

    RGB565_1D = reshape(RGB565, 1, []); % Reshapes the 2D matrix of 16-bit values into a 1D array, which is suitable for use in C
    disp(RGB565_1D(1:10)); % Displays the first ten values of the 1D array for verification purposes.

Here is a link to know more about “bitshift” function:

https://www.mathworks.com/help/matlab/ref/bitshift.html

Hope this helps!