Sorting and searching problem related to a group of people standing in a rectangle
Split it up!  The current method does more than one thing, I'd create at least three helper methods:

int[][] parseInput(String[] input);
int getMaxOfMinHeightInColumns(int[][] peoples);
int getMinOfMaxHeightInRows(int[][] peoples);


It would be easier to follow and understand.
I looks like a bug that the following testcase fails:

@Test
public void test() {
    String[] input = {"9 2 3",
     "4 8 7"};
    int[] result = getPeople(input);
    assertArrayEquals(new int[] {4, 7}, result);
}

Reusing the count variable is a bad sing:


count=0;



Try to use two different variables for different purposes and more descriptive names. What does it count? Put that into the name of the variable.
A few explanatory variable would be more readable here and remove some duplication:


String[][]findMaxOfMin = new String[people.length][people[0].split(" ").length];
int[][] findMinOfMax = new int[people[0].split(" ").length][people.length];



Consider creating one for people.length and another for people[0].split(" ").length (columnNumber, rowNumber, for example).
(String[]) casting seems unnecessary here:


temp[j] = Integer.valueOf( ((String[])people[j].split(" "))[i]);