python - 使用 OpenCV 删除图像的背景

Question

该代码适用于高分辨率图像。但有时当图像的分辨率不够好或背景颜色与图像中的颜色匹配时，它可以完全去除背景。有时，在移除的背景图像中留下白色斑块。以下是示例。在左边的原始图像上，在右边的图像上删除了背景图像。

输入图像

从下面的代码输出图像

期望的输出

右边是输入图像，右边是可以完全去除背景的代码的输出图像。

下面是描述使用 OpenCV 删除图像背景的过程的代码。

def remove_background(img):
    #== Parameters =======================================================================
    BLUR = 5
    CANNY_THRESH_1 = 10
    CANNY_THRESH_2 = 100
    MASK_DILATE_ITER = 20
    MASK_ERODE_ITER = 20
    MASK_COLOR = (0.0,0.0,0.0) # In BGR format
    
    #== Processing =======================================================================
    
    #-- Read image -----------------------------------------------------------------------
    img = cv2.imread(img)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    
    #-- Edge detection -------------------------------------------------------------------
    edges = cv2.Canny(gray, CANNY_THRESH_1, CANNY_THRESH_2)
    edges = cv2.dilate(edges, None)
    edges = cv2.erode(edges, None)
    
    #-- Find contours in edges, sort by area ---------------------------------------------
    contour_info = []
    contours, _ = cv2.findContours(edges, cv2.RETR_LIST, cv2.CHAIN_APPROX_NONE)
    
    for c in contours:
        contour_info.append((
            c,
            cv2.isContourConvex(c),
            cv2.contourArea(c),
        ))
    contour_info = sorted(contour_info, key=lambda c: c[2], reverse=True)
    
    
    #-- Create empty mask, draw filled polygon on it corresponding to largest contour ----
    # Mask is black, polygon is white
    mask = np.zeros(edges.shape)
    for c in contour_info:
        cv2.fillConvexPoly(mask, c[0], (255))
    # cv2.fillConvexPoly(mask, max_contour[0], (255))
    
    #-- Smooth mask, then blur it --------------------------------------------------------
    mask = cv2.dilate(mask, None, iterations=MASK_DILATE_ITER)
    mask = cv2.erode(mask, None, iterations=MASK_ERODE_ITER)
    mask = cv2.GaussianBlur(mask, (BLUR, BLUR), 0)
    mask_stack = np.dstack([mask]*3)    # Create 3-channel alpha mask
    
    #-- Blend masked img into MASK_COLOR background --------------------------------------
    mask_stack  = mask_stack.astype('float32') / 255.0          # Use float matrices, 
    img         = img.astype('float32') / 255.0                 #  for easy blending
    
    masked = (mask_stack * img) + ((1 - mask_stack) * MASK_COLOR) # Blend
    masked = (masked * 255).astype('uint8')                     # Convert back to 8-bit 
    cv2.imwrite('img.png', masked)

标签： pythonopencvmachine-learningimage-processingcomputer-vision