matlab图像处理基础知识1（双线性插值matlab实现--等比例调整缩放倍数）

需求说明：FPGA图像处理前期算法验证

当前状态：已通过matlab验证

%当前算法只能等比例放大或者缩小

function scaler_bilinear_matlab()

%-----------------------------0:配置输入输出--------------------------------

I=imread('F:\book\Digital image processing and machine vision\640480\plane.jpg');%读入原图像

[width_sr,height_sr,l]=size(I); %读取图像矩阵大小，方便后面操作

K = str2double(inputdlg('please input scale factor (must between 0.2 - 5.0)', 'INPUT scale factor', 1, {'0.5'}));

width = K * width_sr;

height = K * height_sr;

O = uint8(zeros(width,height,l));

widthScale = width_sr/width; %横向放大系数

heightScale = height_sr/height; %纵向放大系数

%-----------------------------1:开始输出计算--------------------------------

for x = 5:width - 5 % 5是为了防止矩阵超出边界溢出

for y = 5:height - 5

xx = x * widthScale; % xx, yy为原坐标，x,y为新坐标

yy = y * heightScale;

%-----------------------------2:边界处理-----------------------------------

if (xx/double(uint16(xx)) == 1.0) & (yy/double(uint16(yy)) == 1.0)

O(x,y,:) = I(int16(xx),int16(yy),:); % 若xx，yy为整数，直接赋值

else

%-----------------------------3:原坐标四个相邻点----------------------------

a = double(uint16(xx)); % xx, yy为原坐标，x,y为新坐标

b = double(uint16(yy)); % xx, yy为原坐标，x,y为新坐标

x11 = double(I(a, b, :)); % x11 <- I(a,b)

x12 = double(I(a, b+1,:)); % x12 <- I(a,b+1)

x21 = double(I(a+1,b, :)); % x21 <- I(a+1,b)

x22 = double(I(a+1,b+1,:)); % x22 <- I(a+1,b+1)

%-----------------------------4:计算输出图像数值----------------------------

O(x,y,:) = uint8( (b+1-yy) * ( (xx-a)*x21 + (a+1-xx)*x11 ) + (yy-b) * ( (xx-a)*x22 + (a+1-xx) * x12) );% 用双线性插值计算公式计算

end

end

end

%-----------------------------6:输出显示------------------------------------

figure,imshow(I); title('输入图像640*480');

figure,imshow(uint8(O));title('输出图像1920*1080');

设计来自：时间的诗