Decoding 0s and 1s into an image

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. You are decoding a black-and-white image. What do you do for a 1 in the code?

A Leave that square white

B Colour that square in

2. You are decoding a black-and-white image. What do you do for a 0 in the code?

A Leave that square white

B Colour that square in

3. Which way do you fill in the grid when you decode a code?

A Row by row, starting at the top left

B Any square you like, in any order

4. A grid is 4 squares wide. The code is 1001 0110 0110 1001. How many squares are in the first row?

A 4 squares: 1001

B 8 squares: 10010110

5. You have decoded a grid and the picture looks like a messy jumble. What should you do?

A Decide the picture is finished and stop

B Check the code and the grid size, then try again

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
101110		AA row where all 5 squares are coloured in
211111		BA row of 5 squares: leave the first white, colour the next three, leave the last white
3Decode a grid by reading the code one row at a time, from the top row down		C1 = colour, 0 = white
4A 0 means leave the square white and a 1 means colour it		DThe row has 5 digits but the grid is only 4 squares wide, so the code and the grid do not match. Check the picture makes sense before sharing it.
5Code 0110: colour squares 1 and 4, leave 2 and 3 white		EThe colours are swapped. The 1s are in squares 2 and 3, so those get coloured, and the 0s in squares 1 and 4 stay white.
6Row 1 of a 4-square grid: 10101 so colour 5 squares		FRow 1: 10001 Row 2: 01010

Definitions

decode

Fill in the Blanks

Complete each line of code by filling in the missing parts.

IF bit = _ THEN colour the square

ELSE leave the square _____

FOR each ___ in the grid read the bits from left to right colour a square for each 1

row1 ← "0110" square 1 is 0, so leave it white square 2 is _, so colour it

1. Decode the code into a grid 2. _____ the picture makes sense

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A read the code row by row

B if digit is 1, colour it in

C if digit is 0, colour it in

Question 2

A grid = 4 columns by 4 rows

B start at the top left square

C read the first row of digits

D move down after each digit

Question 3

A Code: 0110 1001 1001

B Row 1 is 0110, so: X _ _ X

C Row 2 is 1001, so: X _ _ X

Question 4

A Grid is 3 columns wide

B Each row needs 4 digits

C Row code 101 fits the row

Question 5

A A colours a 3x3 grid

B A writes 1 for coloured cells

C A writes 2 for white cells

D A gives the code to B

Answer Key

Decoding 0s and 1s into an image

Section A: Quick Questions

B — Colour that square in

A — Leave that square white

A — Row by row, starting at the top left

A — 4 squares: 1001

B — Check the code and the grid size, then try again

Section B: Match the Pairs

01110 → A row of 5 squares: leave the first white, colour the next three, leave the last white

11111 → A row where all 5 squares are coloured in

Decode a grid by reading the code one row at a time, from the top row down → Row 1: 10001 Row 2: 01010

A 0 means leave the square white and a 1 means colour it → 1 = colour, 0 = white

Code 0110: colour squares 1 and 4, leave 2 and 3 white → The colours are swapped. The 1s are in squares 2 and 3, so those get coloured, and the 0s in squares 1 and 4 stay white.

Row 1 of a 4-square grid: 10101 so colour 5 squares → The row has 5 digits but the grid is only 4 squares wide, so the code and the grid do not match. Check the picture makes sense before sharing it.

Section C: Definitions

decode — To turn a code back into a picture: fill the grid row by row, colouring a square for each 1 and leaving it white for each 0. Then check the picture makes sense.

Section D: Fill in the Blanks

IF bit = 1 THEN colour the square

ELSE leave the square white

FOR each row in the grid
  read the bits from left to right
  colour a square for each 1

row1 ← "0110"
square 1 is 0, so leave it white
square 2 is 1, so colour it

1. Decode the code into a grid
2. Check the picture makes sense

Section E: Spot the Error

C — A 0 means the square stays white. Only a 1 is coloured in, so the line should be: if digit is 0, leave it white.

D — Each row is read from left to right, so after each digit you move right along the row. You only move down when the row is finished.

B — 0110 means white, coloured, coloured, white. The broken line colours the wrong squares. It should be: _ X X _.

B — The grid is 3 columns wide, so each row of the code needs exactly 3 digits. It should say 3 digits, not 4.

C — Binary code only uses 0 and 1. White cells are written as 0, so the line should be: A writes 0 for white cells.