通过OpenCV在C ++中通过非常小的步骤翻译图像 [英] Translate image by very small step by OpenCV in C++

问题描述

我正在通过非常小的步长进行图像翻译（比如在1/1024栏中翻译）

I'm doing image translation by very small step sizes (like translate in column by 1/1024)

考虑我有以下图像（我创建图像在opencv中使用Mat并使用类型CV_64F）：

Consider I have the following image (I create the image with "Mat" in opencv and with the type CV_64F):

255  0
 0   0

现在通过（1/1024）列进行翻译我希望如下：

Now by doing translation in column by (1/1024) I would expect the following:

254.7509765625 0.2490234375
     0               0

但我得到的是相同的源图像！：

But what I get is the same source image!:

255  0
 0   0 

如何获得预期结果？

这是我正在翻译的代码：

Here is the code I'm doing the translation:

Mat sourceImg = (Mat_<double>(2, 2) << 255.0, 0, 0, 0);
double translateColumn, translateRow;
translateColumn = 1.0/1024.0;
translateRow = 0.0;   

Mat translationMatrix = (Mat_<double>(2, 3) << 1, 0, translateColumn, 0, 1, translateRow);

Mat translatedImage;
warpAffine(sourceImage, translatedImage, translationMatrix , sourceImage.size());

任何想法都将不胜感激。

Any idea would be appreciated.

推荐答案

找到文件中不精确的原因

Found the reason of imprecision in file

imgproc.hpp

imgproc.hpp

插值使用预先计算的查找表，使用的位数定义了这些表的大小，以及近似。

Interpolation uses precomputed lookup tables and number of used bits defines the size of these tables, and accuracy of approximation.

似乎在片段中定义：

enum InterpolationMasks {
       INTER_BITS      = 5,
       INTER_BITS2     = INTER_BITS * 2,
       INTER_TAB_SIZE  = 1 << INTER_BITS,
       INTER_TAB_SIZE2 = INTER_TAB_SIZE * INTER_TAB_SIZE
     };

或者你可以使用这种方法（在网上找到）：

Alternatively you can use this method (found in web):

/* 
 *  Software License Agreement (BSD License)
 *
 *  Copyright (c) 2012, Willow Garage, Inc.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   * Neither the name of Willow Garage, Inc. nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 *  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *
 *  File:    shift.hpp
 *  Author:  Hilton Bristow
 *  Created: Aug 23, 2012
 */

#ifndef SHIFT_HPP_
#define SHIFT_HPP_

#include <limits>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>

/*! @brief shift the values in a matrix by an (x,y) offset
 *
 * Given a matrix and an integer (x,y) offset, the matrix will be shifted
 * such that:
 *
 *  src(a,b) ---> dst(a+y,b+x)
 *
 * In the case of a non-integer offset, (e.g. cv::Point2f(-2.1, 3.7)),
 * the shift will be calculated with subpixel precision using bilinear
 * interpolation.
 *
 * All valid OpenCV datatypes are supported. If the source datatype is
 * fixed-point, and a non-integer offset is supplied, the output will
 * be a floating point matrix to preserve subpixel accuracy.
 *
 * All border types are supported. If no border type is supplied, the
 * function defaults to BORDER_CONSTANT with 0-padding.
 *
 * The function supports in-place operation.
 *
 * Some common examples are provided following:
 * \code
 *  // read an image from file
 *  Mat mat = imread(filename);
 *  Mat dst;
 *
 *  // Perform Matlab-esque 'circshift' in-place
 *  shift(mat, mat, Point(5, 5), BORDER_WRAP);
 *
 *  // Perform shift with subpixel accuracy, padding the missing pixels with 1s
 *  // NOTE: if mat is of type CV_8U, then it will be converted to type CV_32F
 *  shift(mat, mat, Point2f(-13.7, 3.28), BORDER_CONSTANT, 1);
 *
 *  // Perform subpixel shift, preserving the boundary values
 *  shift(mat, dst, Point2f(0.093, 0.125), BORDER_REPLICATE);
 *
 *  // Perform a vanilla shift, integer offset, very fast
 *  shift(mat, dst, Point(2, 2));
 * \endcode
 *
 * @param src the source matrix
 * @param dst the destination matrix, can be the same as source
 * @param delta the amount to shift the matrix in (x,y) coordinates. Can be
 * integer of floating point precision
 * @param fill the method used to fill the null entries, defaults to BORDER_CONSTANT
 * @param value the value of the null entries if the fill type is BORDER_CONSTANT
 */
void shift(const cv::Mat& src, cv::Mat& dst, cv::Point2f delta, int fill=cv::BORDER_CONSTANT, cv::Scalar value=cv::Scalar(0,0,0,0)) {

    // error checking
    assert(fabs(delta.x) < src.cols && fabs(delta.y) < src.rows);

    // split the shift into integer and subpixel components
    cv::Point2i deltai(ceil(delta.x), ceil(delta.y));
    cv::Point2f deltasub(fabs(delta.x - deltai.x), fabs(delta.y - deltai.y));

    // INTEGER SHIFT
    // first create a border around the parts of the Mat that will be exposed
    int t = 0, b = 0, l = 0, r = 0;
    if (deltai.x > 0) l =  deltai.x;
    if (deltai.x < 0) r = -deltai.x;
    if (deltai.y > 0) t =  deltai.y;
    if (deltai.y < 0) b = -deltai.y;
    cv::Mat padded;
    cv::copyMakeBorder(src, padded, t, b, l, r, fill, value);

    // SUBPIXEL SHIFT
    float eps = std::numeric_limits<float>::epsilon();
    if (deltasub.x > eps || deltasub.y > eps) {
        switch (src.depth()) {
            case CV_32F:
            {
                cv::Matx<float, 1, 2> dx(1-deltasub.x, deltasub.x);
                cv::Matx<float, 2, 1> dy(1-deltasub.y, deltasub.y);
                sepFilter2D(padded, padded, -1, dx, dy, cv::Point(0,0), 0, cv::BORDER_CONSTANT);
                break;
            }
            case CV_64F:
            {
                cv::Matx<double, 1, 2> dx(1-deltasub.x, deltasub.x);
                cv::Matx<double, 2, 1> dy(1-deltasub.y, deltasub.y);
                sepFilter2D(padded, padded, -1, dx, dy, cv::Point(0,0), 0, cv::BORDER_CONSTANT);
                break;
            }
            default:
            {
                cv::Matx<float, 1, 2> dx(1-deltasub.x, deltasub.x);
                cv::Matx<float, 2, 1> dy(1-deltasub.y, deltasub.y);
                padded.convertTo(padded, CV_32F);
                sepFilter2D(padded, padded, CV_32F, dx, dy, cv::Point(0,0), 0, cv::BORDER_CONSTANT);
                break;
            }
        }
    }

    // construct the region of interest around the new matrix
    cv::Rect roi = cv::Rect(std::max(-deltai.x,0),std::max(-deltai.y,0),0,0) + src.size();
    dst = padded(roi);
}


#endif /* SHIFT_HPP_ */

似乎工作正常。

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