问题描述
这里 tf.browser.fromPixels 返回一个只有零的张量.image.data 包含预期的值(不仅仅是零).tfjs 是使用脚本标签加载的.tfjs 1.0.0 但更改版本无济于事.
Here tf.browser.fromPixels returns a tensor with only zeros. image.data contains values as expected (not only zeros). tfjs is loaded using a script tag. tfjs 1.0.0 but changing release does not help.
有什么问题?大概是什么蠢事.我是 Tensorflow.js 的新手...
What can be wrong? Probably something stupid. I am new to Tensorflow.js...
<canvas id="canvas" width="100" height="100" style="border:1px solid #FF0000;"></canvas>
....
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var image = ctx.getImageData(0, 0, canvas.height, canvas.width);
var x = tf.browser.fromPixels(image);
推荐答案
创建后，画布的所有像素值都设置为 0.
When created, the canvas has all its pixel values set to 0.
var canvas = document.getElementById('canvas');
canvas 是一个只有 0 个值的 imageData.创建的张量的值为 0 并不奇怪，因为用于创建它的画布除了 0 值之外没有任何图像数据.
canvas is an imageData with only 0 values. It is no surprise that the tensor created has its values to 0 since the canvas used to created it does not have any image data except 0 values.
CSS 样式不会改变 canvas 的底层值.结果，即使有设置为红色的border-color，也不会反映在imageData上.
The CSS style does not change the underlying value of canvas. As a result, even if there is a border-color that is set to red, it is not reflected on the imageData.
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var image = ctx.getImageData(0, 0, canvas.height, canvas.width);
var x = tf.browser.fromPixels(image);
console.log(x.shape) // height, width, 3<html>
<head>
<!-- Load TensorFlow.js -->
<script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs@1.0.0"> </script>
</head>
<body>
<canvas id="canvas" width="100" height="100" style="border:1px solid #FF0000;"></canvas>
</body>
</html>这篇关于tf.browser.fromPixels 只返回零的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！