#!/usr/bin/env python'''This module contais some common routines used by other samples.'''import numpy as npimport cv2import osfrom contextlib import contextmanagerimport itertools as itimage_extensions = ['.bmp', '.jpg', '.jpeg', '.png', '.tif', '.tiff', '.pbm', '.pgm', '.ppm']class Bunch(object): def __init__(self, **kw): self.__dict__.update(kw) def __str__(self): return str(self.__dict__)def splitfn(fn): path, fn = os.path.split(fn) name, ext = os.path.splitext(fn) return path, name, extdef anorm2(a): return (a*a).sum(-1)def anorm(a): return np.sqrt( anorm2(a) )def homotrans(H, x, y): xs = H[0, 0]*x + H[0, 1]*y + H[0, 2] ys = H[1, 0]*x + H[1, 1]*y + H[1, 2] s = H[2, 0]*x + H[2, 1]*y + H[2, 2] return xs/s, ys/sdef to_rect(a): a = np.ravel(a) if len(a) == 2: a = (0, 0, a[0], a[1]) return np.array(a, np.float64).reshape(2, 2)def rect2rect_mtx(src, dst): src, dst = to_rect(src), to_rect(dst) cx, cy = (dst[1] - dst[0]) / (src[1] - src[0]) tx, ty = dst[0] - src[0] * (cx, cy) M = np.float64([[ cx, 0, tx], [ 0, cy, ty], [ 0, 0, 1]]) return Mdef lookat(eye, target, up = (0, 0, 1)): fwd = np.asarray(target, np.float64) - eye fwd /= anorm(fwd) right = np.cross(fwd, up) right /= anorm(right) down = np.cross(fwd, right) R = np.float64([right, down, fwd]) tvec = -np.dot(R, eye) return R, tvecdef mtx2rvec(R): w, u, vt = cv2.SVDecomp(R - np.eye(3)) p = vt[0] + u[:,0]*w[0] # same as np.dot(R, vt[0]) c = np.dot(vt[0], p) s = np.dot(vt[1], p) axis = np.cross(vt[0], vt[1]) return axis * np.arctan2(s, c)def draw_str(dst, (x, y), s): cv2.putText(dst, s, (x+1, y+1), cv2.FONT_HERSHEY_PLAIN, 1.0, (0, 0, 0), thickness = 2, lineType=cv2.CV_AA) cv2.putText(dst, s, (x, y), cv2.FONT_HERSHEY_PLAIN, 1.0, (255, 255, 255), lineType=cv2.CV_AA)class Sketcher: def __init__(self, windowname, dests, colors_func): self.prev_pt = None self.windowname = windowname self.dests = dests self.colors_func = colors_func self.dirty = False self.show() cv2.setMouseCallback(self.windowname, self.on_mouse) def show(self): cv2.imshow(self.windowname, self.dests[0]) def on_mouse(self, event, x, y, flags, param): pt = (x, y) if event == cv2.EVENT_LBUTTONDOWN: self.prev_pt = pt if self.prev_pt and flags & cv2.EVENT_FLAG_LBUTTON: for dst, color in zip(self.dests, self.colors_func()): cv2.line(dst, self.prev_pt, pt, color, 5) self.dirty = True self.prev_pt = pt self.show() else: self.prev_pt = None# palette data from matplotlib/_cm.py_jet_data = { 'red': ((0., 0, 0), (0.35, 0, 0), (0.66, 1, 1), (0.89,1, 1), (1, 0.5, 0.5)), 'green': ((0., 0, 0), (0.125,0, 0), (0.375,1, 1), (0.64,1, 1), (0.91,0,0), (1, 0, 0)), 'blue': ((0., 0.5, 0.5), (0.11, 1, 1), (0.34, 1, 1), (0.65,0, 0), (1, 0, 0))}cmap_data = { 'jet' : _jet_data }def make_cmap(name, n=256): data = cmap_data[name] xs = np.linspace(0.0, 1.0, n) channels = [] eps = 1e-6 for ch_name in ['blue', 'green', 'red']: ch_data = data[ch_name] xp, yp = [], [] for x, y1, y2 in ch_data: xp += [x, x+eps] yp += [y1, y2] ch = np.interp(xs, xp, yp) channels.append(ch) return np.uint8(np.array(channels).T*255)def nothing(*arg, **kw): passdef clock(): return cv2.getTickCount() / cv2.getTickFrequency()@contextmanagerdef Timer(msg): print msg, '...', start = clock() try: yield finally: print "%.2f ms" % ((clock()-start)*1000)class StatValue: def __init__(self, smooth_coef = 0.5): self.value = None self.smooth_coef = smooth_coef def update(self, v): if self.value is None: self.value = v else: c = self.smooth_coef self.value = c * self.value + (1.0-c) * vclass RectSelector: def __init__(self, win, callback): self.win = win self.callback = callback cv2.setMouseCallback(win, self.onmouse) self.drag_start = None self.drag_rect = None def onmouse(self, event, x, y, flags, param): x, y = np.int16([x, y]) # BUG if event == cv2.EVENT_LBUTTONDOWN: self.drag_start = (x, y) if self.drag_start: if flags & cv2.EVENT_FLAG_LBUTTON: xo, yo = self.drag_start x0, y0 = np.minimum([xo, yo], [x, y]) x1, y1 = np.maximum([xo, yo], [x, y]) self.drag_rect = None if x1-x0 > 0 and y1-y0 > 0: self.drag_rect = (x0, y0, x1, y1) else: rect = self.drag_rect self.drag_start = None self.drag_rect = None if rect: self.callback(rect) def draw(self, vis): if not self.drag_rect: return False x0, y0, x1, y1 = self.drag_rect cv2.rectangle(vis, (x0, y0), (x1, y1), (0, 255, 0), 2) return True @property def dragging(self): return self.drag_rect is not Nonedef grouper(n, iterable, fillvalue=None): '''grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx''' args = [iter(iterable)] * n return it.izip_longest(fillvalue=fillvalue, *args)def mosaic(w, imgs): '''Make a grid from images. w -- number of grid columns imgs -- images (must have same size and format) ''' imgs = iter(imgs) img0 = imgs.next() pad = np.zeros_like(img0) imgs = it.chain([img0], imgs) rows = grouper(w, imgs, pad) return np.vstack(map(np.hstack, rows))def getsize(img): h, w = img.shape[:2] return w, hdef mdot(*args): return reduce(np.dot, args)def draw_keypoints(vis, keypoints, color = (0, 255, 255)): for kp in keypoints: x, y = kp.pt cv2.circle(vis, (int(x), int(y)), 2, color) 第15行： Bunch函数是将传入 的参数作为一个字典便于查询使用。使用例程如下
>>> jack = Bunch(a=4,b=5,c=6)>>> print(jack){ 'c': 6, 'a': 4, 'b': 5} bokeyuan={ "b":1, "o":2, "k":3, "e":4, "y":5, "u":6, "a":7, "n":8, }
该对象是用于将一个字典转化成对象的代码例如 现在想转化一个对象，我们通常会这样写
class Dict2Obj: def __init__(self,bokeyuan): self.b = bokeyuan['b'] self.o = bokeyuan['o'] self.k = bokeyuan['k'] self.e = bokeyuan['e'] self.y = bokeyuan['y'] self.u = bokeyuan['u'] self.a = bokeyuan['a'] self.n = bokeyuan['n']
但是在了解这个方法时候我们会这样写，
1 class Dict2Obj:2 def __init__(self,bokeyuan):3 self.__dict__.update(bokeyuan)
然后这样调用
jack = Dict2Obj（bokeyuan）
总结：__dict__用于显示该对象的所有字典元素。__dict__.update()用于更新或者添加元素。
第21行：该函数的作用是传入路径，os.path.split分割 路径名和文件名 os.path.splitext传入文件名.后缀 用于分割文件名和后缀
>>> os.path.split('jack/2/3/asd.jpg')('jack/2/3', 'asd.jpg')>>> os.path.splitext('asd.jpg')('asd', '.jpg')
第26行： 矩阵相乘，然后每一行进行求和返回新的矩阵
第28行： 将第26行的结果开方
第31行： 3*3的矩阵 将第一行的元素乘以x第二行乘以x第三行乘以x 然后将第一行和第二行的结果除以第三行。
第37行： np.ravel将矩阵多维矩阵a （其中只有四个元素或两个元素）转化为一维矩阵，如果其中只有两个元素的话，进行如下操作
a = (0, 0, a[0], a[1])
然后将其转化为float类型的2*2的矩阵。
第43行： rect2rect_mtx(src, dst): 首先将传入的两个图像进行to_rect(a) 操作，然后（dst的第2行-第一行）/（src的第二行-第一行），