windowing_test.ipynb

windowing_test.ipynb

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      "name": "python"
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  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
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      "source": [
        "<a href=\"https://colab.research.google.com/gist/enakai00/2b42aaef56df1ad66028b156b56f1357/windowing_test.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
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    {
      "cell_type": "code",
      "source": [
        "import numpy as np\n",
        "import matplotlib.pyplot as plt"
      ],
      "metadata": {
        "id": "20OegdHJYXyD"
      },
      "execution_count": 1,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "ImageDepth = 65535    # 画像データの解像度 [0, ImageDepth]\n",
        "DisplayDepth = 4096   # ディスプレイの解像度 [0, DisplayDepth]"
      ],
      "metadata": {
        "id": "zaEe2sICCnWO"
      },
      "execution_count": 2,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "# 補正してから反転\n",
        "def window_invert(image, wc, ww):\n",
        "    iinfo = np.iinfo(image.dtype)\n",
        "    bottom = wc - ww // 2\n",
        "    top = wc + ww // 2\n",
        "    image = np.clip(image, bottom, top) # [bottom, top] の外側を切り詰める\n",
        "    image = np.interp(image, (bottom, top), (0, DisplayDepth)) # [bottom, top] を [0, DisplayDepth] に拡大する（ここで、丸めが生じる）\n",
        "    image = DisplayDepth - image # 全体を反転する\n",
        "    return image.astype(iinfo)"
      ],
      "metadata": {
        "id": "SG8tRHO0ZPBP"
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      "execution_count": 3,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "# 反転してから補正\n",
        "def invert_window(image, wc, ww):\n",
        "    iinfo = np.iinfo(image.dtype)\n",
        "    image = ImageDepth - image # 全体を反転する\n",
        "    wc = ImageDepth - wc # WindowCenter も対応させて反転する\n",
        "    bottom = wc - ww // 2\n",
        "    top = wc + ww // 2\n",
        "    image = np.clip(image, bottom, top) # [bottom, top] の外側を切り詰める\n",
        "    image = np.interp(image, (bottom, top), (0, DisplayDepth)) # [bottom, top] を [0, DisplayDepth] に拡大する（ここで、丸めが生じる）\n",
        "    return image.astype(iinfo)"
      ],
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        "id": "HlmI7n86YfJ_"
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      "execution_count": 4,
      "outputs": []
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    {
      "cell_type": "code",
      "source": [
        "wc = 3308\n",
        "ww = 2048\n",
        "image = np.random.randint(0, ImageDepth, (255, 255)) # 乱数で画像を生成\n",
        "image0 = window_invert(image.copy(), wc, ww) # 補正してから反転\n",
        "image1 = invert_window(image.copy(), wc, ww) # 反転してから補正"
      ],
      "metadata": {
        "id": "RlrUIt-JaM7a"
      },
      "execution_count": 7,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "(image0 == image1).mean() # 2つの結果の一致度を計算 (100% 一致で 1.0)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
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        "id": "DH4k68Ofb5wE",
        "outputId": "465ee4d4-5c3b-4e1a-e215-cef135bdcce7"
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      "execution_count": 8,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "1.0"
            ]
          },
          "metadata": {},
          "execution_count": 8
        }
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}