add

Question_21_30/answers/answer_21.py

@@ -9,13 +9,14 @@
 # Trans [0, 255]
 a, b = 0., 255.
 
-vmin = img.min()
-vmax = img.max()
+c = img.min()
+d = img.max()
 
 out = img.copy()
-out[out<a] = a
-out[out>b] = b
-out = (b-a) / (vmax - vmin) * (out - vmin) + a
+
+out = (b-a) / (d - c) * (out - c) + a
+out[out < a] = a
+out[out > b] = b
 out = out.astype(np.uint8)
 
 # Display histogram

Question_21_30/answers_cpp/answer_25.cpp

@@ -0,0 +1,41 @@
+#include <opencv2/core.hpp>
+#include <opencv2/highgui.hpp>
+#include <iostream>
+#include <math.h>
+
+int main(int argc, const char* argv[]){
+  cv::Mat img = cv::imread("imori.jpg", cv::IMREAD_COLOR);
+
+  int width = img.rows;
+  int height = img.cols;
+
+  double rx = 1.5, ry = 1.5;
+
+  int resized_width = (int)(width * rx);
+  int resized_height = (int)(height * ry);
+  int x_before, y_before;
+
+  cv::Mat out = cv::Mat::zeros(resized_height, resized_width, CV_8UC3);
+
+  // nearest neighbor interpolation
+  for (int y = 0; y < resized_height; y++){
+    y_before = (int)round(y / ry);
+    y_before = fmin(y_before, height - 1);
+
+    for (int x = 0; x < resized_width; x++){
+      x_before = (int)round(x / rx);
+      x_before = fmin(x_before, width - 1);
+
+      for (int k = 0; k < 3; k++){
+	out.at<cv::Vec3b>(y, x)[k] = img.at<cv::Vec3b>(y_before, x_before)[k];
+      }
+    }
+  }
+
+  //cv::imwrite("out.jpg", out);
+  cv::imshow("answer", out);
+  cv::waitKey(0);
+  cv::destroyAllWindows();
+
+  return 0;
+}

Question_21_30/answers_cpp/answer_26.cpp

@@ -0,0 +1,49 @@
+#include <opencv2/core.hpp>
+#include <opencv2/highgui.hpp>
+#include <iostream>
+#include <math.h>
+
+int main(int argc, const char* argv[]){
+  cv::Mat img = cv::imread("imori.jpg", cv::IMREAD_COLOR);
+
+  int width = img.rows;
+  int height = img.cols;
+
+  double rx = 1.5, ry = 1.5;
+
+  int resized_width = (int)(width * rx);
+  int resized_height = (int)(height * ry);
+  int x_before, y_before;
+  double dx, dy;
+  double val;
+
+  cv::Mat out = cv::Mat::zeros(resized_height, resized_width, CV_8UC3);
+
+  // bi-linear interpolation
+  for (int y = 0; y < resized_height; y++){
+    y_before = (int)floor(y / ry);
+    y_before = fmin(y_before, height - 1);
+    dy = y / ry - y_before;
+
+    for (int x = 0; x < resized_width; x++){
+      x_before = (int)floor(x / rx);
+      x_before = fmin(x_before, width - 1);
+      dx = x / rx - x_before;
+
+      for (int k = 0; k < 3; k++){
+	val = (1. - dx) * (1. - dy) * img.at<cv::Vec3b>(y_before, x_before)[k] +
+	  dx * (1. - dy) * img.at<cv::Vec3b>(y_before, x_before + 1)[k] +
+	  (1. - dx) * dy * img.at<cv::Vec3b>(y_before + 1, x_before)[k] +
+	  dx * dy * img.at<cv::Vec3b>(y_before + 1, x_before)[k];
+	out.at<cv::Vec3b>(y, x)[k] = (uchar)val;
+      }
+    }
+  }
+
+  //cv::imwrite("out.jpg", out);
+  cv::imshow("answer", out);
+  cv::waitKey(0);
+  cv::destroyAllWindows();
+
+  return 0;
+}

Question_21_30/answers_cpp/answer_27.cpp

@@ -0,0 +1,79 @@
+#include <opencv2/core.hpp>
+#include <opencv2/highgui.hpp>
+#include <iostream>
+#include <math.h>
+
+double h(double t){
+  double a = -1;
+  if (fabs(t) <= 1){
+    return (a + 2) * pow(fabs(t), 3) - (a + 3) * pow(fabs(t), 2) + 1;
+  } else if(fabs(t) <= 2){
+    return a * pow(fabs(t), 3) - 5 * a * pow(fabs(t), 2) + 8 * a * fabs(t) - 4 * a;
+  } 
+  return 0;
+}
+
+int val_clip(int x, int min, int max){
+  return fmin(fmax(x, min), max);
+}
+
+
+int main(int argc, const char* argv[]){
+  cv::Mat img = cv::imread("imori.jpg", cv::IMREAD_COLOR);
+
+  int width = img.rows;
+  int height = img.cols;
+
+  double rx = 1.5, ry = 1.5;
+
+  int resized_width = (int)(width * rx);
+  int resized_height = (int)(height * ry);
+  int x_before, y_before;
+  double dx, dy, wx, wy, w_sum;
+  double val;
+  int _x, _y;
+
+  cv::Mat out = cv::Mat::zeros(resized_height, resized_width, CV_8UC3);
+
+  // bi-cubic interpolation
+  for (int y = 0; y < resized_height; y++){
+    dy = y / ry;
+    y_before = (int)floor(dy);
+
+    for (int x = 0; x < resized_width; x++){
+      dx = x / rx;
+      x_before = (int)floor(dx);
+
+
+      for (int k = 0; k < 3; k++){
+	w_sum = 0;
+	val = 0;
+
+	for (int j = -1; j < 3; j++){
+	  _y = val_clip(y_before + j, 0, height - 1);
+	  wy = h(fabs(dy - _y));
+
+	  for (int i = -1; i < 3; i++){
+	    _x = val_clip(x_before + i, 0, width - 1);
+	    wx = h(fabs(dx - _x));
+	    w_sum += wy * wx;
+	    val += (double)img.at<cv::Vec3b>(_y, _x)[k] * wx * wy;
+	  }
+	}
+
+	val /= w_sum;
+
+	val = val_clip(val, 0, 255);
+	out.at<cv::Vec3b>(y, x)[k] = (uchar)val;
+      }
+    }
+  }
+
+  //cv::imwrite("out.jpg", out);
+  cv::imshow("answer", out);
+  cv::waitKey(0);
+  cv::destroyAllWindows();
+
+  return 0;
+}
+

Tutorial/sample_ex.html

@@ -0,0 +1,63 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="utf-8"/>
+        <title>Image Processing</title>
+
+    </head>
+
+    <body>
+        <h1>Image Processing!</h1>
+
+        <canvas id="canvas" style="border: solid thin black;"></canvas>
+        <canvas id="canvas_result"  style="border: solid thin black;"></canvas>
+
+        <br>
+        <button onclick="process();" style="margin-left: 90px; font-size: 20px;">process!</button>
+
+    <script type="text/javascript">
+        let image = new Image();
+        var src = "imori.jpg";
+        image.src = src;
+        const canvas = document.getElementById("canvas");
+        const ctx = canvas.getContext("2d");
+        const canvas_result = document.getElementById("canvas_result");
+        const ctx_result = canvas_result.getContext("2d");
+        image.onload = () => {
+            canvas.width = image.width;
+            canvas.height = image.height;
+
+            ctx.drawImage(image, 0, 0, canvas.width, canvas.height);
+
+            canvas_result.width = image.width;
+            canvas_result.height = image.height;
+        }
+
+        function process(){
+
+            let src = ctx.getImageData(0, 0, image.width, image.height);
+            let dst = ctx_result.createImageData(image.width, image.height);
+
+            //for ( var i = 0; i < 128; i++){ src.data[i * 4] = 255;}
+
+            /*
+            src.data[29 * 4 + 19 * 128 * 4] = 255;
+            src.data[29 * 4 + 19 * 128 * 4 + 1] = 0;
+            src.data[29 * 4 + 19 * 128 * 4 + 2] = 0;
+            //src.data[29 * 4 + 19 * 128 + 3] = 0;
+            */
+
+            for (let i = 0; i < src.data.length; i+= 4){
+                dst.data[i] = src.data[i];
+                dst.data[i+1] = src.data[i+1];
+                dst.data[i+2] = src.data[i+2];
+                dst.data[i+3] = src.data[i+3];
+            }
+
+            ctx_result.putImageData(dst, 0, 0);
+        }
+
+    </script>
+
+    </body>
+</html>