Computer Science - 9210 OxfordAQA

Representing Images

Akopọ

Hold a phone screen close enough and the photograph on it stops being a photograph. What you see instead is a grid of tiny coloured squares, laid out in rows and columns, each one a flat single colour. Step back and your eye blends them into a face or a landscape. That grid is the entire secret of how a machine that stores nothing but numbers manages to store a picture: the picture is chopped into squares and each square is written down as a number.

This lesson teaches you the two measurements that describe such an image, its size in pixels and its colour depth, and shows you how those two numbers alone determine the file size. You will calculate file sizes in bits and in bytes, turn a pattern of binary digits into a picture and a picture back into binary digits, and be able to say precisely what a photographer is trading away when they choose a smaller file.

Awọn Afojusun

  1. Understand what a pixel is and be able to describe how pixels relate to an image and the way images are displayed.
  2. Describe the following for bitmaps:
  3. size in pixels
  4. colour depth.
  5. Describe how a bitmap represents an image using pixels and colour depth. Describe using examples how the number of pixels and colour depth can affect the file size of a bitmap image.
  6. Calculate bitmap image file sizes based on the number of pixels and colour depth.
  7. Convert binary data into an image.
  8. Convert an image into binary data.

Àwòrán ọpọlọ

A ti ṣe àwòrán kókó yìí kí o lè rí bí àwọn èrò ṣe so pọ̀.

Ṣí àwòrán ọpọlọ nínú áàpù

Akọ̀wé Ẹ̀kọ́

A screen cannot draw a smooth curve. What it can do is switch several million tiny lights on and off independently, and if the lights are small enough and close enough together, a staircase of squares reads to the eye as a curve. Each of those tiny elements is a pixel, a word squeezed out of picture element. A pixel is a single point in a graphical image, and it holds exactly one colour.

Àkọsílẹ̀ Ẹ̀kọ́ Pípé wà lórí Ohun Èlò Green Bridge

Gba ohun èlò Green Bridge CBT sórí fóònù tàbí kọ̀mpútà rẹ fún gbogbo ilé ìkàwé IGCSE: ìwé ìdánwò àtijọ́, ìlànà ìdíwọ̀n, àwòrán èrò, káàdì ìkẹ́kọ̀ọ́ àti ẹ̀kọ́ ohùn.

Awọn akọsilẹ ẹkọ ni kikun pẹlu awọn aworan apejuwe
Oluranlọwọ ẹkọ ti AI ṣe agbara rẹ
Ìdánwò àdáṣe onítọ̀kọ̀ tí a ń ṣàyẹ̀wò lẹ́sẹ̀kẹsẹ̀ tí o bá parí
O wa lori Android, Windows, macOS, ati Linux Áàpù iOS ń bọ̀ láìpẹ́

Ìdánwò Ẹ̀kọ́

Oriire fun ipari ẹkọ lori Representing Images. Ni bayi ti o ti ṣawari naa awọn imọran bọtini ati awọn imọran, o to akoko lati fi imọ rẹ si idanwo. Ẹka yii nfunni ni ọpọlọpọ awọn adaṣe awọn ibeere ti a ṣe lati fun oye rẹ lokun ati ṣe iranlọwọ fun ọ lati ṣe iwọn oye ohun elo naa.

Iwọ yoo pade adalu awọn iru ibeere, pẹlu awọn ibeere olumulo pupọ, awọn ibeere idahun kukuru, ati awọn ibeere iwe kikọ. Gbogbo ibeere kọọkan ni a ṣe pẹlu iṣaro lati ṣe ayẹwo awọn ẹya oriṣiriṣi ti imọ rẹ ati awọn ogbon ironu pataki.

Lo ise abala yii gege bi anfaani lati mu oye re lori koko-ọrọ naa lagbara ati lati ṣe idanimọ eyikeyi agbegbe ti o le nilo afikun ikẹkọ. Maṣe jẹ ki awọn italaya eyikeyi ti o ba pade da ọ lójú; dipo, wo wọn gẹgẹ bi awọn anfaani fun idagbasoke ati ilọsiwaju.

  1. What does the term pixel stand for? A. Picture element B. Pixel encoding layer C. Point in colour D. Primary index Answer: A
  2. An image has a colour depth of 4 bits. How many different colours can each pixel be? A. 4 B. 8 C. 16 D. 32 Answer: C
  3. A bitmap is 10 pixels by 10 pixels with a colour depth of 8 bits. What is its file size in bytes? A. 80 B. 100 C. 800 D. 8,000 Answer: B
  4. An image is stored at 200 x 100 pixels. It is resaved at 400 x 200 pixels with the same colour depth. How does the file size change? A. It stays the same B. It doubles C. It quadruples D. It halves Answer: C
  5. An image uses exactly 5 different colours. What is the minimum colour depth needed? A. 2 bits B. 3 bits C. 5 bits D. 8 bits Answer: B

Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà

Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà

Ṣe Adaṣe Awọn Ibeere Idanwo Adaṣe

Ṣe o fẹ ṣe adaṣe awọn ibeere idanwo adaṣe nipa Representing Images? Ṣe igbasilẹ ohun elo Green Bridge CBT lati wọle si awọn ibeere idanwo adaṣe ati awọn ayẹwo adaṣe kikun fun koko-ọrọ yii.

Ṣe igbasilẹ ohun elo naa lori Google Playstore

Gbogbo ohun ti o nilo lati ṣe dara julọ ninu JAMB, WAEC ati NECO.

Green Bridge CBT Mobile App
Asiko ẹkọ AI ti ara ẹni Chat Assistant
Ìbéèrè ìdánwò IGCSE, JAMB, WAEC ati NECO tó ju 200,000 lọ
Fiwọn 1200 Awọn akọsilẹ Ẹkọ ju.
Atilẹyin Aisinipo - Kọ ẹkọ Nigbakugba, Nibi gbogbo
Tẹ̀dí Green Bridge
Àkójọpọ̀ Ìtàn Lítíréṣọ̀ & Ìbéèrè Tó Lè Dáyéé ṣẹ́lẹ̀
Tẹle iṣẹ ṣiṣe rẹ ati ilọsiwaju rẹ.
Àlàyé tí ó jinlẹ̀ fún ìmòye tó jinlẹ̀.