Be more accepting of blobs at larger distances

This fixes some missing blobs at distance in the caffeteria.

Change-Id: I32fad1f0e989a5833cbcb3b24108d8ce12d0a9df
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/y2022/vision/blob_detector.cc b/y2022/vision/blob_detector.cc
index 93c72d7..2f90513 100644
--- a/y2022/vision/blob_detector.cc
+++ b/y2022/vision/blob_detector.cc
@@ -133,7 +133,7 @@
   }
 
   // Threshold for mean distance from a blob centroid to a circle.
-  constexpr double kCircleDistanceThreshold = 1.0;
+  constexpr double kCircleDistanceThreshold = 2.0;
   // We should only expect to see blobs between these angles on a circle.
   constexpr double kDegToRad = M_PI / 180.0;
   constexpr double kMinBlobAngle = 50.0 * kDegToRad;