Prática de Shadowing: C4W1L01 Computer Vision - Aprenda a falar inglês com vídeo

Escolha um modo de prática

Cada modo abre uma sala de prática em tela cheia.

62 frases
Se as frases estiverem muito curtas ou longas, clique em Edit para ajustá-las.
1
Welcome to this course on convolutional networks.
2
Computer vision is one of the areas that's been advancing rapidly thanks to deep learning.
3
Deep learning computer vision is now helping self-driving cars figure out where are the other cars
4
and the pedestrians around it so it's avoid them.
5
It's making face recognition work much better than ever before so
6
that perhaps some of you will soon or perhaps already be able to unlock a phone, unlock even a door using just your face.
7
And if you look on your cell phone, I bet you have many apps that show you pictures of food
8
or pictures of a hotel or just fun pictures of scenery.
9
And some of the companies that build those apps are using deep learning to help show you the most attractive, the most beautiful, or the most relevant pictures.
10
And I think deep learning is even enabling new types of art to be created.
11
So I think the two reasons I'm excited about deep learning for computer vision and why I think you might be too.
12
First, rapid advances in computer vision are enabling brand new applications to be built that just weren't possible a few years ago.
13
And by learning these tools, perhaps you will be able to invent some of these new products and applications.
14
Second, even if you don't end up building computer vision systems per se, I found that because the computer vision research community has been
15
so creative and so inventive and coming up with new neural network architectures and algorithms, algorithms is actually inspired a lot of cross fertilization into other areas as well.
16
For example, when I was working on speech recognition, I sometimes actually took inspiration from ideas from computer vision and borrowed them into the speech literature.
17
So even if you don't end up working on computer vision, I hope
18
that you find some of the ideas you learned about in this course helpful for some of your algorithms and your architectures.
19
So with that, let's get started.
20
Here are some examples of computer vision problems we'll study in this course.
21
You've already seen image classification, sometimes also called image recognition, where you might take as input,
22
say a 64 by 64 image and try to figure out is that a cat.
23
Another example of a computer vision problem is object detection.
24
So if you're building a self-driving car, maybe you don't just need to figure out if there are other cars in this image,
25
but instead you need to figure out the position of the other cars in this picture
26
so that your car can avoid them.
27
So in object detection, usually we have to not just figure out that these other objects, say cause in the picture, but also draw boxes around them.
28
We'll have some other way of recognizing where in the picture are these objects.
29
And notice also in this example that there can be multiple calls in the same picture, or at least every one of them within a certain distance of your call.
30
Here's another example, maybe a more fun one is neural style transfer.
31
Let's say you have a picture and you want this picture repainted in a different style.
32
So, neural style transfer, you have a content image and you have a style image.
33
The image on the right is actually a Picasso.
34
And you can have a neural network, put them together to repaint the content image that is the image on the left, but in the style of the image on the right,
35
and you end up with the image at the bottom.
36
So albums like this are enabling new types of artwork to be created.
37
And in this course, you learn how to do this yourself as well.
38
One of the challenges of computer vision problems is that the inputs can get really big.
39
For example, in previous courses, you've worked with 64 by 64 images.
40
And so that's 64 by 64 by 3 because there's three color channels.
41
And if you multiply that out, that's 12288.
42
So X, the input features has dimension 12288.
43
And that's not too bad.
44
But 64 by 64 is actually a very small image.
45
If you work with larger images, maybe this is a thousand pixel by thousand pixel image, and that's actually just one megapixel,
46
but the dimension of the input features will be thousand by thousand by three because you have three RGB channels,
47
and that's three million.
48
And if you're viewing this on a smaller screen, this might not be apparent, but this is actually a low-res 64 by 64 image, and this is a higher-res thousand by thousand image.
49
But if you have 3 million input features, then this means that x here will be 3 million dimensional.
50
And so if in the first hidden layer, maybe you have just a thousand hidden units,
51
then the total number of weights that is the matrix W1,
52
if you use a standard fully connected network like we have in causes one or two,
53
this matrix will be a 1000 by 3 million dimensional matrix.
54
Because X is now R by 3 million, 3M, I'm using it to denote 3 million.
55
And this means that this matrix here will have 3 billion parameters, which is just very, very large.
56
And with that many parameters, it's difficult to get enough data to prevent the neural network from overfitting,
57
and also the computational requirements and memory requirements to train a neural network with three billion parameters is just a bit infeasible.
58
But for computer vision applications, you don't want to be stuck using only tiny little images.
59
You want to use large images.
60
To do that, you need to implement the convolution operation, which is one of the fundamental building blocks of convolutional neural networks.
61
Let's see what this means and how you can implement this in the next video.
62
I will illustrate convolutions using the example of edge detection.

Baixar aplicativo

Tudo o que você precisa para falar fluentemente

Pronúncia com IANota em cada frase
Prática de IPADomine cada som
VocabulárioMonte seu banco de palavras
Jogo de vocabulárioAprenda brincando

Mesmo canal

FOR YOU

Vídeo recomendado

Vocabulário e dicas de fala para esta lição

Este vídeo tem 62 frases e 981 palavras para praticar shadowing. A fala dura 5:44. O falante fala em ritmo natural, cerca de 171 palavras por minuto, próximo de uma conversa do dia a dia. 86% das palavras estão entre as 3.000 mais comuns do inglês; vale a pena estudar o restante antes de começar.

Vocabulário principal deste vídeo

15 palavras do vídeo que vale a pena aprender, com pronúncia e significado:

PalavraPronúnciaSignificado
neural adjetivo/ˈnʊɹəl/neural
recognition substantivo/ˌɹɛkəɡˈnɪʃ(ə)n/reconhecimento
enable verbo/ɪˈneɪ.bəl/habilitar, possibilitar
detection substantivo/dɪˈtɛk.ʃən/detecção, deteção
algorithm substantivo/ˈælɡəɹɪðm̩/algoritmo
parameter substantivo/pəˈɹæm.ə.tɚ/parâmetro
architecture substantivo/ˈɑː.kɪˌtɛk.t͡ʃə/arquitetura
requirement substantivo/ɹɪˈkwaɪɹmənt/exigência, requisito
implement verbo/ˈɪmpləmənt/implementar
dimensional adjetivo/daɪˈmɛn.ʃə.nəl/dimensional
dimension substantivo/daɪˈmɛn.ʃən/dimensão
unlock verbo/ʌnˈlɑk/destrancar
pixel substantivo/ˈpɪk.səl/pixel, píxel
helpful adjetivo/ˈhɛlp.fl̩/prestável, útil
inspiration substantivo/ˌɪn.spɪˈɹeɪ.ʃən/inspiração

Phrasal verbs que você vai ouvir

PalavraSignificado
figure out verbodescobrir, deduzir
end up verboterminar, acabar
come up with verbopensar (em), alcançar

Gramática neste vídeo

As estruturas que o falante mais usa, com as palavras exatas do vídeo:

EstruturaNo vídeo
Voz passiva be + particípio passado — o foco está no que acontece, não em quem fazbe created · be built · is actually inspired
Present perfect have/has + particípio passado — uma ação passada que ainda importa agorahas been · You've already seen · you've worked
Orações relativas who / which + oração — informação extra sobre uma pessoa ou coisaparameters, which is · operation, which is

Pronúncia para ficar de olho

O falante usa 13 contrações e formas reduzidas, como don't, I'm, we'll. Diga-as na forma curta, do jeito que você ouve.

  • Os sons de “sh” e “zh”: recognition /ˌɹɛkəɡˈnɪʃ(ə)n/, detection /dɪˈtɛk.ʃən/, dimensional /daɪˈmɛn.ʃə.nəl/, dimension /daɪˈmɛn.ʃən/, inspiration /ˌɪn.spɪˈɹeɪ.ʃən/
  • Palavras longas — acerte a sílaba tônica: recognition /ˌɹɛkəɡˈnɪʃ(ə)n/, parameter /pəˈɹæm.ə.tɚ/, architecture /ˈɑː.kɪˌtɛk.t͡ʃə/, dimensional /daɪˈmɛn.ʃə.nəl/, inspiration /ˌɪn.spɪˈɹeɪ.ʃən/

Como praticar com este vídeo

  1. Ouça o vídeo inteiro uma vez sem falar e anote as palavras que você não conhece.
  2. Comece na velocidade 0,75×, faça shadowing frase por frase e volte à velocidade normal quando ficar fácil.
  3. Grave a sua voz e compare com o original, prestando atenção a palavras como neural, recognition, enable.

O que é a Técnica de Shadowing?

Shadowing é uma técnica de aprendizado de idiomas com base científica, originalmente desenvolvida para o treinamento de intérpretes profissionais. O método é simples, mas poderoso: você ouve áudio em inglês nativo e repete imediatamente em voz alta — como uma sombra seguindo o falante com 1-2 segundos de atraso. Pesquisas mostram melhora significativa na precisão da pronúncia, entonação, ritmo, sons conectados, compreensão auditiva e fluência na fala.

Técnica de shadowing: leia o guia completo passo a passo →