diff --git a/cspuz_rs/src/solver/ndarray.rs b/cspuz_rs/src/solver/ndarray.rs
index 185f0c83..f7fb6480 100644
--- a/cspuz_rs/src/solver/ndarray.rs
+++ b/cspuz_rs/src/solver/ndarray.rs
@@ -2,6 +2,7 @@ use super::traits::{ArrayShape, Item, Operand, PropagateBinary, PropagateTernary
 use crate::items::Arrow;
 use crate::solver::traits::BoolArrayLike;
 use crate::solver::traits::IntArrayLike;
+use crate::solver::BoolExprArray1D;
 use std::ops::{Bound, Not, RangeBounds};
 
 use cspuz_core::csp::BoolExpr as CSPBoolExpr;
@@ -599,46 +600,67 @@ where
     Self: Operand<Shape = (usize, usize), Value = CSPBoolExpr>,
 {
     pub fn conv2d_and(&self, filter: (usize, usize)) -> NdArray<(usize, usize), CSPBoolExpr> {
-        self.conv2d_impl(filter, CSPBoolExpr::And)
+        conv2d_impl(self, filter, |parts| {
+            CSPBoolExpr::And(parts.into_iter().map(Box::new).collect())
+        })
     }
 
     pub fn conv2d_or(&self, filter: (usize, usize)) -> NdArray<(usize, usize), CSPBoolExpr> {
-        self.conv2d_impl(filter, CSPBoolExpr::Or)
+        conv2d_impl(self, filter, |parts| {
+            CSPBoolExpr::Or(parts.into_iter().map(Box::new).collect())
+        })
     }
 
-    fn conv2d_impl<F>(&self, filter: (usize, usize), op: F) -> NdArray<(usize, usize), CSPBoolExpr>
-    where
-        F: Fn(Vec<Box<CSPBoolExpr>>) -> CSPBoolExpr,
-    {
-        let orig = self.as_ndarray();
-        let (h, w) = orig.shape;
-        let (fh, fw) = filter;
-        assert!(h >= fh);
-        assert!(w >= fw);
+    pub fn conv2d_count_true(&self, filter: (usize, usize)) -> NdArray<(usize, usize), CSPIntExpr> {
+        conv2d_impl(self, filter, |parts| {
+            let array = BoolExprArray1D::from_raw(parts);
+            array.count_true().data.0
+        })
+    }
+}
 
-        let mut data = vec![];
-        for y in 0..=(h - fh) {
-            for x in 0..=(w - fw) {
-                let mut part = vec![];
-                for dy in 0..fh {
-                    for dx in 0..fw {
-                        part.push(Box::new(orig.data[(y + dy) * w + (x + dx)].clone()));
-                    }
+fn conv2d_impl<A, I, O, F>(
+    array: &NdArray<(usize, usize), A>,
+    filter: (usize, usize),
+    op: F,
+) -> NdArray<(usize, usize), O>
+where
+    A: Clone,
+    I: Clone,
+    O: Clone,
+    NdArray<(usize, usize), A>: Operand<Shape = (usize, usize), Value = I>,
+    F: Fn(Vec<I>) -> O,
+{
+    let orig = array.as_ndarray();
+    let (h, w) = orig.shape;
+    let (fh, fw) = filter;
+    assert!(h >= fh);
+    assert!(w >= fw);
+
+    let mut data = vec![];
+    for y in 0..=(h - fh) {
+        for x in 0..=(w - fw) {
+            let mut part = vec![];
+            for dy in 0..fh {
+                for dx in 0..fw {
+                    part.push(orig.data[(y + dy) * w + (x + dx)].clone());
                 }
-                data.push(op(part));
             }
+            data.push(op(part));
         }
+    }
 
-        NdArray {
-            shape: (h - fh + 1, w - fw + 1),
-            data,
-        }
+    NdArray {
+        shape: (h - fh + 1, w - fw + 1),
+        data,
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::super::Solver;
+    use cspuz_core::csp::BoolExpr as CSPBoolExpr;
+    use cspuz_core::csp::IntExpr as CSPIntExpr;
 
     #[test]
     fn test_ndarray_add_0d_0d() {
@@ -938,4 +960,76 @@ mod tests {
             assert_eq!(model.get(b), -3);
         }
     }
+
+    #[test]
+    fn test_ndarray_conv2d_and() {
+        let mut solver = Solver::new();
+        let a = &solver.bool_var_2d((4, 5));
+        let b = a.conv2d_and((2, 2));
+
+        assert_eq!(b.shape(), (3, 4));
+        for y in 0..3 {
+            for x in 0..4 {
+                let expected = CSPBoolExpr::And(vec![
+                    Box::new(a.at((y, x)).data.0.expr()),
+                    Box::new(a.at((y, x + 1)).data.0.expr()),
+                    Box::new(a.at((y + 1, x)).data.0.expr()),
+                    Box::new(a.at((y + 1, x + 1)).data.0.expr()),
+                ]);
+                assert_eq!(&expected, &b.at((y, x)).data.0);
+            }
+        }
+    }
+
+    #[test]
+    fn test_ndarray_conv2d_or() {
+        let mut solver = Solver::new();
+        let a = &solver.bool_var_2d((4, 5));
+        let b = a.conv2d_or((2, 2));
+
+        assert_eq!(b.shape(), (3, 4));
+        for y in 0..3 {
+            for x in 0..4 {
+                let expected = CSPBoolExpr::Or(vec![
+                    Box::new(a.at((y, x)).data.0.expr()),
+                    Box::new(a.at((y, x + 1)).data.0.expr()),
+                    Box::new(a.at((y + 1, x)).data.0.expr()),
+                    Box::new(a.at((y + 1, x + 1)).data.0.expr()),
+                ]);
+                assert_eq!(&expected, &b.at((y, x)).data.0);
+            }
+        }
+    }
+
+    #[test]
+    fn test_ndarray_conv2d_count_true() {
+        let mut solver = Solver::new();
+        let a = &solver.bool_var_2d((4, 5));
+        let b = a.conv2d_count_true((2, 2));
+
+        assert_eq!(b.shape(), (3, 4));
+        for y in 0..3 {
+            for x in 0..4 {
+                let expected = {
+                    let mut terms = vec![];
+                    for dy in 0..2 {
+                        for dx in 0..2 {
+                            terms.push((
+                                Box::new(
+                                    a.at((y + dy, x + dx))
+                                        .data
+                                        .0
+                                        .expr()
+                                        .ite(CSPIntExpr::Const(1), CSPIntExpr::Const(0)),
+                                ),
+                                1,
+                            ));
+                        }
+                    }
+                    CSPIntExpr::Linear(terms)
+                };
+                assert_eq!(&expected, &b.at((y, x)).data.0);
+            }
+        }
+    }
 }