Pre-Allocate Space for a Cell Array

I'm working with confocal microscopy images. Specifically Z-stacks. I want to manipulate the images. However, I'm having a problem preallocating the space in memory.

%Open Image
bfopen()

%Extract Image Data
image_data=ans{1,1};

%Create an Array focused on the pixel_data
pixel_data=image_data(:,1);

%Ask User How Many Laser Channels were used to Acquire the Image
total_laser_channels=input('How many laser channels were used to acquire this image?\n');

%Determine the number of image slices in each channel
images_per_channel=length(pixel_data)/total_laser_channels;

*

%Preallocate space and variables for each channel
  if total_laser_channels==1
      channel1{images_per_channel,:}=[];
  elseif total_laser_channels==2
      channel1{images_per_channel,:}=[];
      channel2{images_per_channel,:}=[];
  elseif total_laser_channels==3
      channel1{images_per_channel,:}=[];
      channel2{images_per_channel,:}=[];
      channel3{images_per_channel,:}=[];
  elseif total_laser_channels==4
      channel1{images_per_channel,:}=[];
      channel2{images_per_channel,:}=[];
      channel3{images_per_channel,:}=[];
      channel4{images_per_channel,:}=[];
  elseif total_laser_channels==5
      channel1{images_per_channel,:}=[];
      channel2{images_per_channel,:}=[];
      channel3{images_per_channel,:}=[];
      channel4{images_per_channel,:}=[];
      channel5{images_per_channel,:}=[];
  else
      break
  end*

%Loop: Each laser channel has corresponding images
i=1;
while i<length(pixel_data)+1
    if total_laser_channels==1
        channel1=[channel1;pixel_data(i,1)];
        i=i+1;
    elseif total_laser_channels==2
        channel1=[channel1;pixel_data(i,1)];
        channel2=[channel2;pixel_data(i+1,1)];
        i=i+2;
    elseif total_laser_channels==3
        channel1=[channel1;pixel_data(i,1)];
        channel2=[channel2;pixel_data(i+1,1)];
        channel3=[channel3;pixel_data(i+2,1)];
        i=i+3;
    elseif total_laser_channels==4
        channel1=[channel1;pixel_data(i,1)];
        channel2=[channel2;pixel_data(i+1,1)];
        channel3=[channel3;pixel_data(i+2,1)];
        channel4=[channel4;pixel_data(i+3,1)];
        i=i+4;
    elseif total_laser_channels==5
        channel1=[channel1;pixel_data(i,1)];
        channel2=[channel2;pixel_data(i+1,1)];
        channel3=[channel3;pixel_data(i+2,1)];
        channel4=[channel4;pixel_data(i+3,1)];
        channel5=[channel5;pixel_data(i+4,1)];
        i=i+5;
    else
        display('Too many or wrong number of laser channels.')
        break
    end
end

For the images i'm looking at now the total_laser_channels is 3. images_per_channel is 45. However for channel1, channel2, channel3 after i run the code i get a 46x1 array instead of the 45x1 array that i want.

[]

2048x2048 uint16

2048x2048 uint16

2048x2048 uint16

2048x2048 uint16

2048x2048 uint16

2048x2048 uint16

2048x2048 uint16....

The first position of the cell array has []

Any help would be greatly appreciated.

[Ben11]

Maybe you could use a switch/case and a for loop? On a side note if you want to remove the empty array from your cell array you can use ths:

channel1 = channel1(~cellfun('isempty', channel1));