Fix bogus error message when estimating floor/ceiling from bracketed …

…images. Also add improve the estimation itself a bit.
EatTheFuture · Feb 14, 2024 · d5552e0 · d5552e0
1 parent b09ec31
commit d5552e0
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Showing 2 changed files with 28 additions and 5 deletions.
diff --git a/src/bin/lut_maker/main.rs b/src/bin/lut_maker/main.rs
@@ -382,7 +382,7 @@ impl AppMain {
                     let histogram_sets =
                         bracket_images_to_histogram_sets(&*bracket_image_sets.lock());
 
-                    if histogram_sets.len() < 2 {
+                    if histogram_sets.iter().all(|hs| hs[0].len() < 2 || hs[1].len() < 2 || hs[2].len() < 2) {
                         status.lock_mut().log_warning(format!(
                             "Not enough valid images to estimate floor.  Check that you have at least one dark image or at least two bracketed exposure images with exposure Exif data.",
                         ));
@@ -396,6 +396,9 @@ impl AppMain {
                             return;
                         }
                         for i in 0..3 {
+                            if histograms[i].len() < 2 {
+                                continue;
+                            }
                             let norm = 1.0 / (histograms[i][0].0.buckets.len() - 1) as f32;
                             if let Some((f, _)) = estimate_sensor_floor_ceiling(&histograms[i]) {
                                 if let Some(ref mut floor) = floor[i] {
@@ -444,7 +447,7 @@ impl AppMain {
                     .set_progress(format!("Estimating sensor ceiling"), 0.0);
 
                 let histogram_sets = bracket_images_to_histogram_sets(&*bracket_image_sets.lock());
-                if histogram_sets.len() < 2 {
+                if histogram_sets.iter().all(|hs| hs[0].len() < 2 || hs[1].len() < 2 || hs[2].len() < 2) {
                     status.lock_mut().log_warning(format!(
                         "Not enough valid images to estimate ceiling.  Check that you have at least two bracketed exposure images with exposure Exif data.",
                     ));
@@ -458,6 +461,9 @@ impl AppMain {
                         return;
                     }
                     for i in 0..3 {
+                        if histograms[i].len() < 2 {
+                            continue;
+                        }
                         let norm = 1.0 / (histograms[i][0].0.buckets.len() - 1) as f32;
                         if let Some((_, c)) = estimate_sensor_floor_ceiling(&histograms[i]) {
                             if let Some(ref mut ceiling) = ceiling[i] {

diff --git a/sub_crates/sensor_analysis/src/lib.rs b/sub_crates/sensor_analysis/src/lib.rs
@@ -108,6 +108,19 @@ pub fn estimate_sensor_floor_ceiling(histograms: &[(Histogram, f32)]) -> Option<
         .iter()
         .fold(&histograms[0], |a, b| if a.1 > b.1 { a } else { b });
 
+    let darkest_pixel = lowest_exposed
+        .0
+        .buckets
+        .iter()
+        .position(|c| *c > 0)
+        .unwrap_or(0) as f32;
+    let brightest_pixel = highest_exposed
+        .0
+        .buckets
+        .iter()
+        .rposition(|c| *c > 0)
+        .unwrap_or(highest_exposed.0.buckets.len() - 1) as f32;
+
     let mut sensor_floor = 0.0f32;
     let mut sensor_ceiling = (bucket_count - 1) as f32;
     for i in 0..histograms.len() {
@@ -116,7 +129,9 @@ pub fn estimate_sensor_floor_ceiling(histograms: &[(Histogram, f32)]) -> Option<
         let tmp_i = ((ratio * LOOSENESS) as usize).min(bucket_count * 3 / 4);
         if ratio >= 8.0 && tmp_i > 0 {
             let target_sum = histograms[i].0.sum_under(tmp_i);
-            sensor_floor = sensor_floor.max(lowest_exposed.0.find_sum_lerp(target_sum));
+            sensor_floor = sensor_floor
+                .max(lowest_exposed.0.find_sum_lerp(target_sum))
+                .max(darkest_pixel);
         }
 
         // Ceiling.
@@ -125,7 +140,9 @@ pub fn estimate_sensor_floor_ceiling(histograms: &[(Histogram, f32)]) -> Option<
         if ratio <= 0.125 && tmp_i < (bucket_count - 1) {
             let target_sum = histograms[i].0.sum_under(tmp_i);
             if target_sum > (total_samples / 2) {
-                sensor_ceiling = sensor_ceiling.min(highest_exposed.0.find_sum_lerp(target_sum));
+                sensor_ceiling = sensor_ceiling
+                    .min(highest_exposed.0.find_sum_lerp(target_sum))
+                    .min(brightest_pixel);
             }
         }
     }
@@ -134,7 +151,7 @@ pub fn estimate_sensor_floor_ceiling(histograms: &[(Histogram, f32)]) -> Option<
     // Otherwise return the result, appropriately snapped to image
     // quantization.
     if ((sensor_ceiling - sensor_floor) / bucket_count as f32) >= 0.8 {
-        Some((sensor_floor.floor(), sensor_ceiling.ceil()))
+        Some((sensor_floor, sensor_ceiling.ceil()))
     } else {
         // Failed basic sanity check.
         None