Question

我试图在WebGL 2中显示16位DICOM图像（扩展名为.dcm）。

我可以用下面的代码查看8位的Di-3d.png。但是我无法使用相同的代码加载16位图像。为此，我需要将16位图像转换为8位。

我如何进行转换？

 <script>
    (function () {
        'use strict';

        var canvas = document.createElement('canvas');
        canvas.width = Math.min(window.innerWidth, window.innerHeight);
        canvas.height = canvas.width;
        document.body.appendChild(canvas);

        var gl = canvas.getContext( 'webgl2', { antialias: false } );
        var isWebGL2 = !!gl;
        if(!isWebGL2) {
            document.getElementById('info').innerHTML = 'WebGL 2 is not available.  See <a href="https://www.khronos.org/webgl/wiki/Getting_a_WebGL_Implementation">How to get a WebGL 2 implementation</a>';
            return;
        }

        // -- Init program
        var program = createProgram(gl, getShaderSource('vs'), getShaderSource('fs'));
        var mvpLocation = gl.getUniformLocation(program, 'MVP');
        var diffuseLocation = gl.getUniformLocation(program, 'diffuse');

        // -- Init buffers: vec2 Position, vec2 Texcoord
        var positions = new Float32Array([
            -1.0, -1.0,
             1.0, -1.0,
             1.0,  1.0,
             1.0,  1.0,
            -1.0,  1.0,
            -1.0, -1.0
        ]);
        var vertexPosBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, positions, gl.STATIC_DRAW);
        gl.bindBuffer(gl.ARRAY_BUFFER, null);

        var texCoords = new Float32Array([
            0.0, 1.0,
            1.0, 1.0,
            1.0, 0.0,
            1.0, 0.0,
            0.0, 0.0,
            0.0, 1.0
        ]);
        var vertexTexBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, vertexTexBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, texCoords, gl.STATIC_DRAW);
        gl.bindBuffer(gl.ARRAY_BUFFER, null);

        // -- Init VertexArray
        var vertexArray = gl.createVertexArray();
        gl.bindVertexArray(vertexArray);

        var vertexPosLocation = 0; // set with GLSL layout qualifier
        gl.enableVertexAttribArray(vertexPosLocation);
        gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
        gl.vertexAttribPointer(vertexPosLocation, 2, gl.FLOAT, false, 0, 0);
        gl.bindBuffer(gl.ARRAY_BUFFER, null);

        var vertexTexLocation = 4; // set with GLSL layout qualifier
        gl.enableVertexAttribArray(vertexTexLocation);
        gl.bindBuffer(gl.ARRAY_BUFFER, vertexTexBuffer);
        gl.vertexAttribPointer(vertexTexLocation, 2, gl.FLOAT, false, 0, 0);
        gl.bindBuffer(gl.ARRAY_BUFFER, null);

        gl.bindVertexArray(null);

        loadImage('Di-3d.png', function(image) {
        //loadImage('Anonymized20190509.dcm', function(image) {
            // -- Init Texture
            var texture = gl.createTexture();
            gl.activeTexture(gl.TEXTURE0);
            gl.bindTexture(gl.TEXTURE_2D, texture);
            gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false);
            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

            // -- Render
            gl.clearColor(0.0, 0.0, 0.0, 1.0);
            gl.clear(gl.COLOR_BUFFER_BIT);

            var matrix = new Float32Array([
                0.5, 0.0, 0.0, 0.0,
                0.0, 0.5, 0.0, 0.0,
                0.0, 0.0, 0.5, 0.0,
                0.0, 0.0, 0.0, 1.0
            ]);

            gl.useProgram(program);
            gl.uniformMatrix4fv(mvpLocation, false, matrix);
            gl.uniform1i(diffuseLocation, 0);

            gl.bindVertexArray(vertexArray);

            gl.drawArrays(gl.TRIANGLES, 0, 6);

            // Delete WebGL resources
            gl.deleteBuffer(vertexPosBuffer);
            gl.deleteBuffer(vertexTexBuffer);
            gl.deleteTexture(texture);
            gl.deleteProgram(program);
            gl.deleteVertexArray(vertexArray);
        });
    })();
</script>

Answer 1

您正在尝试显示DICOM图像，而不是PNG图像。

很有可能，即使嵌入的图像每像素8位，loadImage函数也无法理解DICOM。

如何在WebGL 2中显示带有sample.dcm扩展名的16位图像？

1 个答案: