请帮个忙，看看哪里出错了
procedure TForm1.btn1Click(Sender: TObject);
var
pts: array of TPoint;
i,j,k: integer;
begin
k := Random(10)+1;
SetLength(pts,k);
for j:=1 to 10 do
begin
for i:=1 to k do
begin
pts[i].X := Form1.Left + Image.Left + Random(Image.Width);
pts[i].Y := Form1.Top + Image.Top + Random(Image.Height);
end;
Image.Canvas.Polygon(pts);
end;
end;

结果提示什么内存错误

[解决办法]
for i:=0 to k-1 do
或
for i:=low(pts) to high(pts) do