您好,登錄后才能下訂單哦!
如何用Python代碼做一個(gè)換臉程序,相信很多沒有經(jīng)驗(yàn)的人對(duì)此束手無策,為此本文總結(jié)了問題出現(xiàn)的原因和解決方法,通過這篇文章希望你能解決這個(gè)問題。
在這篇文章中我將介紹如何寫一個(gè)簡(jiǎn)短(200行)的 Python 腳本,來自動(dòng)地將一幅圖片的臉替換為另一幅圖片的臉。
這個(gè)過程分四步:
檢測(cè)臉部標(biāo)記。
旋轉(zhuǎn)、縮放、平移和第二張圖片,以配合***步。
調(diào)整第二張圖片的色彩平衡,以適配***張圖片。
把第二張圖像的特性混合在***張圖像中。
該腳本使用 dlib 的 Python 綁定來提取面部標(biāo)記:
Dlib 實(shí)現(xiàn)了 Vahid Kazemi 和 Josephine Sullivan 的《使用回歸樹一毫秒臉部對(duì)準(zhǔn)》論文中的算法。算法本身非常復(fù)雜,但dlib接口使用起來非常簡(jiǎn)單:
PREDICTOR_PATH = "/home/matt/dlib-18.16/shape_predictor_68_face_landmarks.dat" detector = dlib.get_frontal_face_detector() predictor = dlib.shape_predictor(PREDICTOR_PATH) def get_landmarks(im): rects = detector(im, 1) if len(rects) > 1: raise TooManyFaces if len(rects) == 0: raise NoFaces return numpy.matrix([[p.x, p.y] for p in predictor(im, rects[0]).parts()])
get_landmarks()函數(shù)將一個(gè)圖像轉(zhuǎn)化成numpy數(shù)組,并返回一個(gè)68×2元素矩陣,輸入圖像的每個(gè)特征點(diǎn)對(duì)應(yīng)每行的一個(gè)x,y坐標(biāo)。
特征提取器(predictor)需要一個(gè)粗糙的邊界框作為算法輸入,由一個(gè)傳統(tǒng)的能返回一個(gè)矩形列表的人臉檢測(cè)器(detector)提供,其每個(gè)矩形列表在圖像中對(duì)應(yīng)一個(gè)臉。
現(xiàn)在我們已經(jīng)有了兩個(gè)標(biāo)記矩陣,每行有一組坐標(biāo)對(duì)應(yīng)一個(gè)特定的面部特征(如第30行的坐標(biāo)對(duì)應(yīng)于鼻頭)。我們現(xiàn)在要解決如何旋轉(zhuǎn)、翻譯和縮放***個(gè)向量,使它們盡可能適配第二個(gè)向量的點(diǎn)。一個(gè)想法是可以用相同的變換在***個(gè)圖像上覆蓋第二個(gè)圖像。
將這個(gè)問題數(shù)學(xué)化,尋找T,s 和 R,使得下面這個(gè)表達(dá)式:
結(jié)果最小,其中R是個(gè)2×2正交矩陣,s是標(biāo)量,T是二維向量,pi和qi是上面標(biāo)記矩陣的行。
事實(shí)證明,這類問題可以用“常規(guī) Procrustes 分析法”解決:
def transformation_from_points(points1, points2): points1 = points1.astype(numpy.float64) points2 = points2.astype(numpy.float64) c1 = numpy.mean(points1, axis=0) c2 = numpy.mean(points2, axis=0) points1 -= c1 points2 -= c2 s1 = numpy.std(points1) s2 = numpy.std(points2) points1 /= s1 points2 /= s2 U, S, Vt = numpy.linalg.svd(points1.T * points2) R = (U * Vt).T return numpy.vstack([numpy.hstack(((s2 / s1) * R, c2.T - (s2 / s1) * R * c1.T)), numpy.matrix([0., 0., 1.])])
代碼實(shí)現(xiàn)了這幾步:
1.將輸入矩陣轉(zhuǎn)換為浮點(diǎn)數(shù)。這是后續(xù)操作的基礎(chǔ)。
2.每一個(gè)點(diǎn)集減去它的矩心。一旦為點(diǎn)集找到了一個(gè)***的縮放和旋轉(zhuǎn)方法,這兩個(gè)矩心 c1 和 c2 就可以用來找到完整的解決方案。
3.同樣,每一個(gè)點(diǎn)集除以它的標(biāo)準(zhǔn)偏差。這會(huì)消除組件縮放偏差的問題。
4.使用奇異值分解計(jì)算旋轉(zhuǎn)部分??梢栽诰S基百科上看到關(guān)于解決正交 Procrustes 問題的細(xì)節(jié)。
5.利用仿射變換矩陣返回完整的轉(zhuǎn)化。
其結(jié)果可以插入 OpenCV 的 cv2.warpAffine 函數(shù),將圖像二映射到圖像一:
def warp_im(im, M, dshape): output_im = numpy.zeros(dshape, dtype=im.dtype) cv2.warpAffine(im, M[:2], (dshape[1], dshape[0]), dst=output_im, borderMode=cv2.BORDER_TRANSPARENT, flags=cv2.WARP_INVERSE_MAP) return output_im
對(duì)齊結(jié)果如下:
如果我們?cè)噲D直接覆蓋面部特征,很快會(huì)看到這個(gè)問題:
這個(gè)問題是兩幅圖像之間不同的膚色和光線造成了覆蓋區(qū)域的邊緣不連續(xù)。我們?cè)囍拚?/p>
COLOUR_CORRECT_BLUR_FRAC = 0.6 LEFT_EYE_POINTS = list(range(42, 48)) RIGHT_EYE_POINTS = list(range(36, 42)) def correct_colours(im1, im2, landmarks1): blur_amount = COLOUR_CORRECT_BLUR_FRAC * numpy.linalg.norm( numpy.mean(landmarks1[LEFT_EYE_POINTS], axis=0) - numpy.mean(landmarks1[RIGHT_EYE_POINTS], axis=0)) blur_amount = int(blur_amount) if blur_amount % 2 == 0: blur_amount += 1 im1_blur = cv2.GaussianBlur(im1, (blur_amount, blur_amount), 0) im2_blur = cv2.GaussianBlur(im2, (blur_amount, blur_amount), 0) # Avoid divide-by-zero errors. im2_blur += 128 * (im2_blur <= 1.0) return (im2.astype(numpy.float64) * im1_blur.astype(numpy.float64) / im2_blur.astype(numpy.float64))
結(jié)果如下:
此函數(shù)試圖改變 im2 的顏色來適配 im1。它通過用 im2 除以 im2 的高斯模糊值,然后乘以im1的高斯模糊值。這里的想法是用RGB縮放校色,但并不是用所有圖像的整體常數(shù)比例因子,每個(gè)像素都有自己的局部比例因子。
用這種方法兩圖像之間光線的差異只能在某種程度上被修正。例如,如果圖像1是從一側(cè)照亮,但圖像2是被均勻照亮的,色彩校正后圖像2也會(huì)出現(xiàn)未照亮一側(cè)暗一些的問題。
也就是說,這是一個(gè)相當(dāng)簡(jiǎn)陋的辦法,而且解決問題的關(guān)鍵是一個(gè)適當(dāng)?shù)母咚购撕瘮?shù)大小。如果太小,***個(gè)圖像的面部特征將顯示在第二個(gè)圖像中。過大,內(nèi)核之外區(qū)域像素被覆蓋,并發(fā)生變色。這里的內(nèi)核用了一個(gè)0.6 *的瞳孔距離。
用一個(gè)遮罩來選擇圖像2和圖像1的哪些部分應(yīng)該是最終顯示的圖像:
值為1(顯示為白色)的地方為圖像2應(yīng)該顯示出的區(qū)域,值為0(顯示為黑色)的地方為圖像1應(yīng)該顯示出的區(qū)域。值在0和1之間為圖像1和圖像2的混合區(qū)域。
這是生成上圖的代碼:
LEFT_EYE_POINTS = list(range(42, 48)) RIGHT_EYE_POINTS = list(range(36, 42)) LEFT_BROW_POINTS = list(range(22, 27)) RIGHT_BROW_POINTS = list(range(17, 22)) NOSE_POINTS = list(range(27, 35)) MOUTH_POINTS = list(range(48, 61)) OVERLAY_POINTS = [ LEFT_EYE_POINTS + RIGHT_EYE_POINTS + LEFT_BROW_POINTS + RIGHT_BROW_POINTS, NOSE_POINTS + MOUTH_POINTS, ] FEATHER_AMOUNT = 11 def draw_convex_hull(im, points, color): points = cv2.convexHull(points) cv2.fillConvexPoly(im, points, color=color) def get_face_mask(im, landmarks): im = numpy.zeros(im.shape[:2], dtype=numpy.float64) for group in OVERLAY_POINTS: draw_convex_hull(im, landmarks[group], color=1) im = numpy.array([im, im, im]).transpose((1, 2, 0)) im = (cv2.GaussianBlur(im, (FEATHER_AMOUNT, FEATHER_AMOUNT), 0) > 0) * 1.0 im = cv2.GaussianBlur(im, (FEATHER_AMOUNT, FEATHER_AMOUNT), 0) return im mask = get_face_mask(im2, landmarks2) warped_mask = warp_im(mask, M, im1.shape) combined_mask = numpy.max([get_face_mask(im1, landmarks1), warped_mask], axis=0)
我們把上述過程分解:
get_face_mask()的定義是為一張圖像和一個(gè)標(biāo)記矩陣生成一個(gè)遮罩,它畫出了兩個(gè)白色的凸多邊形:一個(gè)是眼睛周圍的區(qū)域,一個(gè)是鼻子和嘴部周圍的區(qū)域。之后它由11個(gè)像素向遮罩的邊緣外部羽化擴(kuò)展,可以幫助隱藏任何不連續(xù)的區(qū)域。
這樣一個(gè)遮罩同時(shí)為這兩個(gè)圖像生成,使用與步驟2中相同的轉(zhuǎn)換,可以使圖像2的遮罩轉(zhuǎn)化為圖像1的坐標(biāo)空間。
之后,通過一個(gè)element-wise***值,這兩個(gè)遮罩結(jié)合成一個(gè)。結(jié)合這兩個(gè)遮罩是為了確保圖像1被掩蓋,而顯現(xiàn)出圖像2的特性。
***,使用遮罩得到最終的圖像:
output_im = im1 * (1.0 - combined_mask) + warped_corrected_im2 * combined_mask
import cv2 import dlib import numpy import sys PREDICTOR_PATH = "/home/matt/dlib-18.16/shape_predictor_68_face_landmarks.dat" SCALE_FACTOR = 1 FEATHER_AMOUNT = 11 FACE_POINTS = list(range(17, 68)) MOUTH_POINTS = list(range(48, 61)) RIGHT_BROW_POINTS = list(range(17, 22)) LEFT_BROW_POINTS = list(range(22, 27)) RIGHT_EYE_POINTS = list(range(36, 42)) LEFT_EYE_POINTS = list(range(42, 48)) NOSE_POINTS = list(range(27, 35)) JAW_POINTS = list(range(0, 17)) # Points used to line up the images. ALIGN_POINTS = (LEFT_BROW_POINTS + RIGHT_EYE_POINTS + LEFT_EYE_POINTS + RIGHT_BROW_POINTS + NOSE_POINTS + MOUTH_POINTS) # Points from the second image to overlay on the first. The convex hull of each # element will be overlaid. OVERLAY_POINTS = [ LEFT_EYE_POINTS + RIGHT_EYE_POINTS + LEFT_BROW_POINTS + RIGHT_BROW_POINTS, NOSE_POINTS + MOUTH_POINTS, ] # Amount of blur to use during colour correction, as a fraction of the # pupillary distance. COLOUR_CORRECT_BLUR_FRAC = 0.6 detector = dlib.get_frontal_face_detector() predictor = dlib.shape_predictor(PREDICTOR_PATH) class TooManyFaces(Exception): pass class NoFaces(Exception): pass def get_landmarks(im): rects = detector(im, 1) if len(rects) > 1: raise TooManyFaces if len(rects) == 0: raise NoFaces return numpy.matrix([[p.x, p.y] for p in predictor(im, rects[0]).parts()]) def annotate_landmarks(im, landmarks): im = im.copy() for idx, point in enumerate(landmarks): pos = (point[0, 0], point[0, 1]) cv2.putText(im, str(idx), pos, fontFace=cv2.FONT_HERSHEY_SCRIPT_SIMPLEX, fontScale=0.4, color=(0, 0, 255)) cv2.circle(im, pos, 3, color=(0, 255, 255)) return im def draw_convex_hull(im, points, color): points = cv2.convexHull(points) cv2.fillConvexPoly(im, points, color=color) def get_face_mask(im, landmarks): im = numpy.zeros(im.shape[:2], dtype=numpy.float64) for group in OVERLAY_POINTS: draw_convex_hull(im, landmarks[group], color=1) im = numpy.array([im, im, im]).transpose((1, 2, 0)) im = (cv2.GaussianBlur(im, (FEATHER_AMOUNT, FEATHER_AMOUNT), 0) > 0) * 1.0 im = cv2.GaussianBlur(im, (FEATHER_AMOUNT, FEATHER_AMOUNT), 0) return im def transformation_from_points(points1, points2): """ Return an affine transformation [s * R | T] such that: sum ||s*R*p1,i + T - p2,i||^2 is minimized. """ # Solve the procrustes problem by subtracting centroids, scaling by the # standard deviation, and then using the SVD to calculate the rotation. See # the following for more details: # https://en.wikipedia.org/wiki/Orthogonal_Procrustes_problem points1 = points1.astype(numpy.float64) points2 = points2.astype(numpy.float64) c1 = numpy.mean(points1, axis=0) c2 = numpy.mean(points2, axis=0) points1 -= c1 points2 -= c2 s1 = numpy.std(points1) s2 = numpy.std(points2) points1 /= s1 points2 /= s2 U, S, Vt = numpy.linalg.svd(points1.T * points2) # The R we seek is in fact the transpose of the one given by U * Vt. This # is because the above formulation assumes the matrix goes on the right # (with row vectors) where as our solution requires the matrix to be on the # left (with column vectors). R = (U * Vt).T return numpy.vstack([numpy.hstack(((s2 / s1) * R, c2.T - (s2 / s1) * R * c1.T)), numpy.matrix([0., 0., 1.])]) def read_im_and_landmarks(fname): im = cv2.imread(fname, cv2.IMREAD_COLOR) im = cv2.resize(im, (im.shape[1] * SCALE_FACTOR, im.shape[0] * SCALE_FACTOR)) s = get_landmarks(im) return im, s def warp_im(im, M, dshape): output_im = numpy.zeros(dshape, dtype=im.dtype) cv2.warpAffine(im, M[:2], (dshape[1], dshape[0]), dst=output_im, borderMode=cv2.BORDER_TRANSPARENT, flags=cv2.WARP_INVERSE_MAP) return output_im def correct_colours(im1, im2, landmarks1): blur_amount = COLOUR_CORRECT_BLUR_FRAC * numpy.linalg.norm( numpy.mean(landmarks1[LEFT_EYE_POINTS], axis=0) - numpy.mean(landmarks1[RIGHT_EYE_POINTS], axis=0)) blur_amount = int(blur_amount) if blur_amount % 2 == 0: blur_amount += 1 im1_blur = cv2.GaussianBlur(im1, (blur_amount, blur_amount), 0) im2_blur = cv2.GaussianBlur(im2, (blur_amount, blur_amount), 0) # Avoid divide-by-zero errors. im2_blur += 128 * (im2_blur <= 1.0) return (im2.astype(numpy.float64) * im1_blur.astype(numpy.float64) / im2_blur.astype(numpy.float64)) im1, landmarks1 = read_im_and_landmarks(sys.argv[1]) im2, landmarks2 = read_im_and_landmarks(sys.argv[2]) M = transformation_from_points(landmarks1[ALIGN_POINTS], landmarks2[ALIGN_POINTS]) mask = get_face_mask(im2, landmarks2) warped_mask = warp_im(mask, M, im1.shape) combined_mask = numpy.max([get_face_mask(im1, landmarks1), warped_mask], axis=0) warped_im2 = warp_im(im2, M, im1.shape) warped_corrected_im2 = correct_colours(im1, warped_im2, landmarks1) output_im = im1 * (1.0 - combined_mask) + warped_corrected_im2 * combined_mask cv2.imwrite('output.jpg', output_im)
看完上述內(nèi)容,你們掌握如何用Python代碼做一個(gè)換臉程序的方法了嗎?如果還想學(xué)到更多技能或想了解更多相關(guān)內(nèi)容,歡迎關(guān)注億速云行業(yè)資訊頻道,感謝各位的閱讀!
免責(zé)聲明:本站發(fā)布的內(nèi)容(圖片、視頻和文字)以原創(chuàng)、轉(zhuǎn)載和分享為主,文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng),如果涉及侵權(quán)請(qǐng)聯(lián)系站長郵箱:is@yisu.com進(jìn)行舉報(bào),并提供相關(guān)證據(jù),一經(jīng)查實(shí),將立刻刪除涉嫌侵權(quán)內(nèi)容。