Question

• int loadVerticalSeam(Pixel** image, int start_col,
  int width, int height, int* seam);

  • This function will traverse through an image starting at the first row at the given start_col. See “Loading a vertical seam” below for how the traversal works. See “Seam Representation” below for how seams are represented.

  • The function returns the total energy of the seam

  • The first parameter is a 2d array of Pixels (structs) that hold a color value

  • The second parameter is the column to start the seam.

  • The third parameter is the width of the array (i.e. the number of columns) needed for traversing the array

  • The fourth parameter is the height of the array (i.e. the number of rows) needed for traversing the array.

  • The fifth parameter is an array to be loaded with column values for each row.

  • Pseudocode

    • Set seam for the first row to the starting column

    • Initialize total energy to the energy for pixel (start_col, 0)

    • For each subsequent row

      • Calculate the energy of each possible next column

      • Set the seam for current row to the column with the minimal energy

      • Add the minimal energy to the total energy

    • Return total energy

    • ***Energy function is already written and correctly outputs energy. Parameters for energy is ==> int energy(Pixel** image, int x, int y, int width, int height)***

• Implement after loadVerticalSeam
  int* findMinVerticalSeam(Pixel** image, int width, int height);

  • This function will traverse through each row, loading its seam in order to find the seam with lowest energy. See “Finding a Minimal Vertical Seam” below for how this works.

  • The function returns a pointer to a seam that is the seam with minimal energy.

  • The first parameter is a 2d array of Pixels (structs) that hold a color value

  • The second parameter is the width of the array (i.e. the number of columns) needed for traversing the array

  • The third parameter is the height of the array (i.e. the number of rows) needed for traversing the array.

  • Pseudocode

    • Set minimal energy to the result of loading the seam for the first column

    • Note minimal seam was loaded by function that returned minimal energy

    • For each column

      • Get energy for the column and load candidate seam

      • If the energy is less than minimal energy

        • Set minimal energy to energy

        • Update minimal seam to be the candidate seam

  • Note: you will have to create seams to pass to loadVerticalSeam

    • You cannot have a memory leak.

  • Language: C++

Answer 1

Pseudocode
Set seam for the first row to the starting column ........... 1
Initialize total energy to the energy for pixel (start_col, 0) ........... 2
For each subsequent row ........... 3
Calculate the energy of each possible next column ........... 4
Set the seam for current row to the column with the minimal energy ........... 5
Add the minimal energy to the total energy ........... 6
Return total energy ........... 7
***Energy function is already written and correctly outputs energy. Parameters for energy is ==>
int energy(Pixel** image, int x, int y, int width, int height)***

int loadVerticalSeam(Pixel** image, int start_col,int width, int height, int* seam){
seam[0]==energy(image,start_col,0, width, height); ........... 1
int total_energy=energy(image,start_col,0, width, height); ........... 2
for(int i=1;i<height;i++){ ........... 3
int min_energy=INT_MAX, min_enegy_index=-1; ........... 4
for(int j=0;j<width;j++) ........... 4
{ ........... 4
if(min_energy>energy(image,j,i, width, height)) ........... 4
{ ........... 4
min_energy=energy(image,j,i, width, height); ........... 4
min_energy_index=j; ........... 4
} ........... 4
} ........... 4
seam[i]=min_energy_index; ........... 5
total_energy=min_energy+total_energy; ........... 6
  
}
return total_energy; ........... 7
}

Pseudocode
Set minimal energy to the result of loading the seam for the first column ........... 1
Note minimal seam was loaded by function that returned minimal energy
For each column ........... 2
Get energy for the column and load candidate seam ........... 3
If the energy is less than minimal energy ........... 4
Set minimal energy to energy ........... 5
Update minimal seam to be the candidate seam ........... 6

Language: C++
int* findMinVerticalSeam(Pixel** image, int width, int height){
int seam[height];
loadVerticalSeam(image, 0, width, height, seam); ........... 1
int minimal_energy=INT_MAX;
int minimal_energy_index=-1;
for(int i=0;i<height;i++){ ........... 1
if(minimal_energy>seam[i]) ...........3 and 4
{   
minimal_energy=energy(image,seam[i],i, width, height); ........... 5
minimal_energy_index=i; ........... 6
}
}
return seam+i;
}