shift.zip_sift拼接_图像拼接_图像拼接shift_图像拼接算法

% [descriptors, locs] = sift(img) % % This function returns IMAGE's SIFT keypoints. % Input parameters: % img: the image. % % Returned: % descriptors: a K-by-128 matrix, where each row gives an invariant % descriptor for one of the K keypoints. The descriptor is a vector % of 128 values normalized to unit length. % locs: K-by-4 matrix, in which each row has the 4 values for a % keypoint location (row, column, scale, orientation). The % orientation is in the range [-PI, PI] radians. % % Credits: Thanks for initial version of this program to D. Alvaro and % J.J. Guerrero, Universidad de Zaragoza (modified by D. Lowe) function [descriptors, locs] = sift(img) % If you have the Image Processing Toolbox, you can uncomment the following % lines to allow input of color images, which will be converted to grayscale. %img=imread('100-0023_img.jpg'); if isrgb(img) img = rgb2gray(img); end [rows, cols] = size(img); % Convert into PGM imagefile, readable by "keypoints" executable f = fopen('tmp.pgm', 'w'); if f == -1 error('Could not create file tmp.pgm.'); end fprintf(f, 'P5\n%d\n%d\n255\n', cols, rows); fwrite(f, img', 'uint8'); fclose(f); % Call keypoints executable if isunix command = '!./sift '; else command = '!siftWin32 '; end command = [command ' <tmp.pgm >tmp.key']; eval(command); % Open tmp.key and check its header g = fopen('tmp.key', 'r'); if g == -1 error('Could not open file tmp.key.'); end [header, count] = fscanf(g, '%d %d', [1 2]); if count ~= 2 error('Invalid keypoint file beginning.'); end num = header(1); len = header(2); if len ~= 128 error('Keypoint descriptor length invalid (should be 128).'); end % Creates the two output matrices (use known size for efficiency) locs = double(zeros(num, 4)); descriptors = double(zeros(num, 128)); % Parse tmp.key for i = 1:num [vector, count] = fscanf(g, '%f %f %f %f', [1 4]); %row col scale ori if count ~= 4 error('Invalid keypoint file format'); end locs(i, :) = vector(1, :); [descrip, count] = fscanf(g, '%d', [1 len]); if (count ~= 128) error('Invalid keypoint file value.'); end % Normalize each input vector to unit length descrip = descrip / sqrt(sum(descrip.^2)); descriptors(i, :) = descrip(1, :); end fclose(g); delete('tmp.pgm');