diff --git a/image_analysis/spot_finding/StrongPixelSet.cpp b/image_analysis/spot_finding/StrongPixelSet.cpp
index 84160aff..c12e12fc 100644
--- a/image_analysis/spot_finding/StrongPixelSet.cpp
+++ b/image_analysis/spot_finding/StrongPixelSet.cpp
@@ -10,7 +10,7 @@
 #include "StrongPixelSet.h"
 
 StrongPixelSet::StrongPixelSet() : strong_pixel_count(0) {
-    pixels.reserve(max_strong_pixel_per_module);
+    pixels.reserve(UINT16_MAX);
 }
 
 void StrongPixelSet::AddStrongPixel(uint16_t col, uint16_t line, int32_t photons) {
@@ -18,16 +18,18 @@ void StrongPixelSet::AddStrongPixel(uint16_t col, uint16_t line, int32_t photons
 }
 
 bool is_far_enough(strong_pixel pixel0, strong_pixel pixel1) {
-    return (pixel1.line - pixel0.line) > 1;
+    auto line_diff = pixel0.line - pixel1.line;
+    return line_diff > 1 || line_diff < -1;
 }
 
 bool is_adjacent(strong_pixel pixel0, strong_pixel pixel1) {
-    return (fabs(pixel0.line - pixel1.line) <= 1) and
-           (fabs(pixel0.col - pixel1.col) <= 1);
+    auto line_diff = pixel0.line - pixel1.line;
+    auto col_diff = pixel0.col - pixel1.col;
+    return line_diff <= 1 && line_diff >= -1 && col_diff <= 1 && col_diff >= -1;
 }
 
-uint16_t StrongPixelSet::find_root(uint16_t e) {
-    uint16_t r = e;
+uint32_t StrongPixelSet::find_root(uint32_t e) {
+    uint32_t r = e;
     //assert(r < L.size());
     while (L[r] != r) {
         r = L[r];
@@ -36,8 +38,8 @@ uint16_t StrongPixelSet::find_root(uint16_t e) {
     return r;
 }
 
-uint16_t StrongPixelSet::make_union(uint16_t e1, uint16_t e2) {
-    uint16_t e;
+uint32_t StrongPixelSet::make_union(uint32_t e1, uint32_t e2) {
+    uint32_t e;
     if (e1 < e2) {
         e = e1;
         //assert(e2 < L.size());
@@ -56,11 +58,11 @@ std::vector<DiffractionSpot> StrongPixelSet::sparseccl() {
     unsigned int labels = 0;
 
     // first scan: pixel association
-    uint16_t start_j = 0;
-    for (uint16_t i = 0; i < pixels.size(); ++i) {
+    uint32_t start_j = 0;
+    for (uint32_t i = 0; i < pixels.size(); ++i) {
         L[i] = i;
-        uint16_t ai = i;
-        for (uint16_t j = start_j; j < i; ++j) {
+        uint32_t ai = i;
+        for (uint32_t j = start_j; j < i; ++j) {
             if (is_adjacent(pixels[i], pixels[j])) {
                 ai = make_union(ai, find_root(j));
             } else if (is_far_enough(pixels[j], pixels[i])) {
@@ -70,7 +72,7 @@ std::vector<DiffractionSpot> StrongPixelSet::sparseccl() {
     }
 
     // second scan: transitive closure
-    for (unsigned int i = 0; i < L.size(); ++i) {
+    for (uint32_t i = 0; i < L.size(); ++i) {
         if (L[i] == i) {
             L[i] = labels++;
         } else {
@@ -80,7 +82,7 @@ std::vector<DiffractionSpot> StrongPixelSet::sparseccl() {
 
     std::vector<DiffractionSpot> spots(labels);
 
-    for (unsigned int i = 0; i < L.size(); i++)
+    for (uint32_t i = 0; i < L.size(); i++)
         spots[L[i]].AddPixel(pixels[i].col, pixels[i].line, pixels[i].counts);
 
     return spots;
@@ -88,7 +90,8 @@ std::vector<DiffractionSpot> StrongPixelSet::sparseccl() {
 
 
 void StrongPixelSet::FindSpotsImage(const SpotFindingSettings &settings, std::vector<DiffractionSpot> &spots) {
-    if (!pixels.empty()) {
+    // Avoid spot finding, when more than 65536 strong pixel count (will be super slow)
+    if (!pixels.empty() && (strong_pixel_count < UINT16_MAX)) {
         for (const auto &spot: sparseccl()) {
             if ((spot.PixelCount() <= settings.max_pix_per_spot)
                 && (spot.PixelCount() >= settings.min_pix_per_spot)) {
@@ -100,7 +103,8 @@ void StrongPixelSet::FindSpotsImage(const SpotFindingSettings &settings, std::ve
 
 void StrongPixelSet::FindSpots(const DiffractionExperiment &experiment, const SpotFindingSettings &settings,
                                std::vector<DiffractionSpot> &spots, uint16_t module_number) {
-    if (!pixels.empty()) {
+    // Avoid spot finding, when more than 65536 strong pixel count (will be super slow)
+    if (!pixels.empty() && (strong_pixel_count < UINT16_MAX)) {
         for (const auto &spot: sparseccl()) {
             if ((spot.PixelCount() <= settings.max_pix_per_spot)
                 && (spot.PixelCount() >= settings.min_pix_per_spot)) {
@@ -114,13 +118,14 @@ void StrongPixelSet::FindSpots(const DiffractionExperiment &experiment, const Sp
 
 void StrongPixelSet::ReadFPGAOutput(const DiffractionExperiment & experiment,
                                     const DeviceOutput &output) {
-    strong_pixel_count += output.spot_finding_result.strong_pixel_count;
-
     // Too many strong pixels will kill performance in data processing, so protection is needed
     // Also if there are no strong pixels, there is no point in looking for them
     if ((output.spot_finding_result.strong_pixel_count == 0) ||
-        (output.spot_finding_result.strong_pixel_count > max_strong_pixel_per_module))
+        (output.spot_finding_result.strong_pixel_count > max_strong_pixel_per_module)) {
+        // If max strong pixel per module condition kicks-in, still report correct strong pixel count
+        strong_pixel_count = output.spot_finding_result.strong_pixel_count;
         return;
+    }
 
     auto pixel_depth = experiment.GetByteDepthImage();
     auto out_ptr = (uint32_t *) output.spot_finding_result.strong_pixel;
diff --git a/image_analysis/spot_finding/StrongPixelSet.h b/image_analysis/spot_finding/StrongPixelSet.h
index c878f5f4..06e05018 100644
--- a/image_analysis/spot_finding/StrongPixelSet.h
+++ b/image_analysis/spot_finding/StrongPixelSet.h
@@ -17,7 +17,7 @@ struct strong_pixel {
 
 class StrongPixelSet {
     std::vector<strong_pixel> pixels;
-    std::vector<uint16_t> L;
+    std::vector<uint32_t> L;
 
     static const constexpr size_t max_strong_pixel_per_module = 4000;
     static const constexpr uint32_t xpixel = RAW_MODULE_COLS;
@@ -25,8 +25,8 @@ class StrongPixelSet {
 
     uint32_t strong_pixel_count;
 
-    uint16_t find_root(uint16_t e);
-    uint16_t make_union(uint16_t e1, uint16_t e2);
+    uint32_t find_root(uint32_t e);
+    uint32_t make_union(uint32_t e1, uint32_t e2);
     std::vector<DiffractionSpot> sparseccl();
 public:
     void ReadFPGAOutput(const DiffractionExperiment& experiment,